high energy – Polkinghorne http://polkinghorne.org/ Thu, 17 Mar 2022 18:30:28 +0000 en-US hourly 1 https://wordpress.org/?v=5.9.3 https://polkinghorne.org/wp-content/uploads/2022/01/icon-2022-01-25T202759.511-150x150.png high energy – Polkinghorne http://polkinghorne.org/ 32 32 Brunel backed to play his part in the future of particle physics https://polkinghorne.org/brunel-backed-to-play-his-part-in-the-future-of-particle-physics/ Fri, 11 Mar 2022 12:05:58 +0000 https://polkinghorne.org/brunel-backed-to-play-his-part-in-the-future-of-particle-physics/ Brunel University London has been supported by funding from the Science and Technology Facilities Council (STFC) to play its part in the future of particle physics research. The university is one of 18 UK institutions to receive a share of a new £60million fund, which the STFC hopes will keep the UK at the forefront […]]]>

Brunel University London has been supported by funding from the Science and Technology Facilities Council (STFC) to play its part in the future of particle physics research.

The university is one of 18 UK institutions to receive a share of a new £60million fund, which the STFC hopes will keep the UK at the forefront of physics, answering some of the questions most fundamental scientists while supporting the next generation of particle physicists. .

The funding will allow Brunel to expand his work at the famous Large Hadron Collider at CERN, where researchers and university students have long worked on some of the biggest experiments in the world.

This work includes maintaining and operating the enormous Compact Muon Solenoid (CMS) Silicon Tracker, a detector that allows scientists to track the momentum of charged particles.

“The Silicon Tracker is at the heart of CERN’s CMS experiment and is one of the largest silicon devices ever built – it measures around 200 square meters. About the size of a tennis court,” said Professor Akram Khan, professor of experimental particle physics at Brunel.

“Its main function in life is to measure particle tracks. When you get a high-energy collision, you get secondary particles from those collisions – and we help determine the trajectory the particles are taking and where they’re coming from.

Using the Silicon Tracker, CERN scientists can track the position of a particle to about 10 microns, or about the width of a human hair.

The new STFC funding will also allow Brunel students and early career researchers to continue working with CERN, where they have already had the opportunity to work on some of the organization’s largest projects.

“Our students have the chance to work on really advanced technologies, such as the electronics of the trigger system. These are bespoke electronic devices that don’t exist anywhere else,” Prof Khan said.

“They may also be involved in testing algorithms, and sometimes developing and tweaking algorithms. But I think the important thing is to get the algorithms and hardware working in real time – they can really get your hands dirty!”

The STFC is one of the main research funding bodies in the UK, supporting particle physicists working in a variety of fields including dark matter, neutrinos and proton decay.

Announcing the funding, Professor Grahame Blair, Executive Director of Programs at STFC, said: “STFC continues to support the experimental particle physics community in the UK by answering fundamental questions about our universe.

“Grants are essential to support technicians, engineers and academics in their skills and expertise in the field, while encouraging career development in basic research with universities and international collaborators.

“This investment supports the UK physics community and enables the UK to remain a leader in the field of experimental particle physics.

Reported by:

Press office, media relations

+44 (0)1895 268965
press-office@brunel.ac.uk

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Beate Heinemann becomes the new director in charge of particle physics at DESY https://polkinghorne.org/beate-heinemann-becomes-the-new-director-in-charge-of-particle-physics-at-desy/ Tue, 07 Dec 2021 08:00:00 +0000 https://polkinghorne.org/beate-heinemann-becomes-the-new-director-in-charge-of-particle-physics-at-desy/ A professor of physics completes the board of directors of the Research Center First woman on the board of DESY: Beate Heinemann. Image: DESY / Angela Pfeiffer Beate Heinemann, DESY Principal Investigator and Professor of Physics at the University of Fribourg, will take over as Director of DESY’s High Energy Physics Division on February 1. […]]]>

A professor of physics completes the board of directors of the Research Center

First woman on the board of DESY: Beate Heinemann. Image: DESY / Angela Pfeiffer

Beate Heinemann, DESY Principal Investigator and Professor of Physics at the University of Fribourg, will take over as Director of DESY’s High Energy Physics Division on February 1. This was unanimously decided by DESY’s supervisory body, the Foundation Council, at its meeting on 7 December. Heinemann is the first female director in the history of DESY.

“Beate Heinemann is a real asset to the research centre,” says Dr. Volkmar Dietz of the Federal Ministry of Education and Research, Chairman of the Foundation Board. “With her international experience, vast knowledge, reputation and forward-looking ideas, she will certainly lead the field of particle physics research into the next exciting era. As the first female CEO, she will mark also the DESY story!”

Beate Heinemann is a true Hamburger, having grown up very close to DESY in Hamburg. She cut her teeth in particle physics experiments and at universities and research centers around the world. After completing her PhD at the University of Hamburg on an experiment at DESY’s HERA accelerator, she joined the CDF experiment at Fermilab near Chicago as a scientist at the University of Liverpool before becoming a professor at the ‘University of California at Berkeley working on the ATLAS experiment, a giant particle detector at CERN in Geneva. From 2013 to 2017, she was deputy spokesperson for the ATLAS experiment. She then returned to Germany to continue her research with ATLAS as a senior scientist at DESY and a professor at the University of Freiburg.

“I am very pleased that Beate Heinemann will join the management of DESY in the future”, says Helmut Dosch, Director of DESY. “His excellent expertise in particle physics and his experience in managing large international teams are perfectly suited to the many facets of fundamental research at DESY and the Helmholtz Association. We are proud to welcome him to the team and have looking forward to shaping the future with her.”

Heinemann succeeds Joachim Mnich, who joined European research center CERN as research director in early 2021, and Ties Behnke, who led the research division as interim director. At DESY, the particle physics division includes not only the particle physicists and technicians involved in the international experiments, but also theorists, the DESY computer department, the library and many service groups such as electronics development.

“DESY is a world-class laboratory and I am thrilled to be part of shaping its present and its future,” says Heinemann. “Many topics and projects are close to my heart – from fundamental research and developments in future technologies to sustainability and diversity. The next decade offers many exciting challenges, both scientifically and socially, and I look forward to the decisive contributions DESY will meet these challenges.”

We spoke to the new director and asked her about her plans and ideas.

What are your plans for your new research center?

As Director, you are not only responsible for your own division, but for DESY as a whole. DESY as a whole is close to my heart. First of all, I think it is very important that we maintain and further expand our pioneering role as a center for fundamental research for the study of matter.

We know that many of the major breakthrough developments and changes stem from basic research. This is why I think it should continue to be the basis of research at DESY – but we also have actions and a research mandate in application-oriented fields, for example climate, digitalization or health . DESY can contribute with all its research areas, for example through new accelerator technologies, new methods for developing detectors or new facilities for photon science. And we must also prioritize sustainability on campus.

Another topic close to my heart, both personally and through my new office, is diversity. DESY must remain a cosmopolitan and diverse laboratory, and there is still room for improvement in many areas, for example the number of women in leadership positions.

And what about your own research division?

Of course, I also have ideas for particle physics, which is based on several very strong pillars at DESY: we participate in international experiments, have our own very interesting experiments on campus, a strong theory group and we are pioneers of digital transformation with our IT sector. . Thanks to our cutting-edge research, we are also very attractive to young scientists who come to us from countries all over the world to do their PhD, postdoctoral research or take up a staff position. We must continue to evolve to stay at the international forefront and review our strategy for the next decade.

In our detector assembly facility here on campus, for example, we are building several core components for the upgrade of experiments as part of the LHC accelerator expansion. DESY has taken on a huge responsibility – it is important that we deliver!

But we can also be proud of the exciting experiments we carry out here at DESY in the framework of international collaboration. The ALPS II experiment will begin next year. ALPS searches for dark matter using small, elusive particles called axions, which also play a role in several other experiments that are on DESY’s wish and planning list. If they all came, which I will of course defend, DESY would be world-leading in the very dynamic field of axion research. The excellent infrastructure we have at DESY as a national research laboratory for particle physics plays a major role here.

We can also be very proud of our theory. It rightly enjoys an excellent reputation around the world, based in particular on the fact that our experts cover more than 60 orders of magnitude in physics – from string theory to cosmology. With the future Wolfgang Pauli Center, it will be even larger and more multidisciplinary.

In the next few years, the course will be set for the successor project to the LHC, namely the next big particle accelerator, the technology and location of which have not yet been chosen. It is very important to me that DESY also actively participates in the preparation of this project in order to maintain and expand its pioneering role.

These are just a few of my ideas and we should always be open to new ones. We have a lot of smart, creative people here, and you never know what spectacular proposition they’ll come up with next.

DESY aside – what are the things that are most important to you?

Above all, durability is very important to me. Our generation bears the responsibility now; we must act now and think climate in everything, both in research and in the development of the DESY campus and Science City Bahrenfeld.

Fundamental research is also close to my heart because not only is it extremely interesting, but it can also stimulate innovation. Take for example the mRNA vaccine, which is based on 20 years of basic research, or the accelerators, which were developed 100 years ago in particle physics and are now used worldwide to treat tumors.

But above all, I am still determined to find out how nature works and what laws of nature underlie it. In my opinion, we are now in the most exciting period in particle physics since the structure of the atom was first discovered and then understood in the early 20th century. In about forty years, physics has been completely revolutionized. At this moment, we are again entering a new energy scale, the electroweak force scale, which is closely related to the Higgs particle and gives us many questions. Studying this scale in detail now is extremely exciting and can also lead to groundbreaking discoveries that no one can even dream of today.

You were born in Hamburg and also studied here. What’s it like to become the first female director at DESY?

First of all, it is a great honor for me to be the first female director at DESY, having taken my first career steps at DESY during my university studies. In general, it is very, very important to me that women have the same opportunities and find the same conditions as men in all areas. In a modern society, we must make the most of everyone’s potential, regardless of gender, religion or social or ethnic origin.

And I’ve always stayed connected to Hamburg: I’m a big HSV fan! As the eldest of three siblings, my dad took me to the stadium from an early age, and to this day I still watch every game with him (although usually on the couch rather than in the stadium) .

DESY is one of the world’s leading particle accelerator centers and studies the structure and function of matter – from the interaction of tiny elementary particles and the behavior of new nanomaterials and vital biomolecules to the great mysteries of the universe. . The particle accelerators and detectors that DESY develops and builds at its sites in Hamburg and Zeuthen are unique research tools. They generate the most intense X-radiation in the world, accelerating particles to record energies and opening new windows on the universe. DESY is a member of the Helmholtz Association, Germany’s largest scientific association, and receives its funding from the German Federal Ministry of Education and Research (BMBF) (90%) and the German federal states of Hamburg and Brandenburg (10%).

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Particle physics experiment may have directly observed dark energy https://polkinghorne.org/particle-physics-experiment-may-have-directly-observed-dark-energy/ Fri, 29 Oct 2021 16:09:08 +0000 https://polkinghorne.org/particle-physics-experiment-may-have-directly-observed-dark-energy/ About 25 years ago, astrophysicists noticed something very interesting about the Universe. The fact that it was expanding had been known since the 1920s, thanks to the observation of Edwin Hubble. But thanks to the observations that astronomers made with the space observatory that bore his name (the The Hubble Space Telescope), they began to […]]]>

About 25 years ago, astrophysicists noticed something very interesting about the Universe. The fact that it was expanding had been known since the 1920s, thanks to the observation of Edwin Hubble. But thanks to the observations that astronomers made with the space observatory that bore his name (the The Hubble Space Telescope), they began to notice how the rate of cosmic expansion was accelerating!

This led to the theory that the Universe is filled with an invisible and mysterious force, known as dark energy (DE). Decades after its proposal, scientists are still trying to pin down this elusive force that accounts for about 70% of the Universe’s energy budget. According to a recent study by an international team of researchers, the XENON1T experiment may have already detected this elusive force, opening new possibilities for future ED research.

The research was led by Dr Sunny Vagnozzi, a researcher at the Kavli Institute of Cosmology (KICC) at the University of Cambridge, and Dr Luca Visinelli, a Fellowship for Innovation (FELLINI) researcher (who is maintained with the support of the Marie Bourse Sklodowska-Curie) at the National Institute of Nuclear Physics (INFN) in Frascati, Italy. They were joined by researchers from the Institute for Theoretical Physics (IPhT), the University of Cambridge and the University of Hawaii.

Both DM and DE are part of the Lambda Cold Dark Matter (LCDM) model of cosmology, which posits that the Universe is filled with cold, slow-moving (DM) particles that interact with normal matter via the force of gravity alone. Lambda represents DE, which is accelerating the expansion of the Universe. Since they are only discerned by observing their effect on the large-scale structure of the Universe, conventional thought holds that none of the forces interact with normal matter via electromagnetism or the weak or strong nuclear force. .

However, some DM theories posit that there is some level of interaction with visible matter, which researchers are actively testing. However, instead of more test results, astrophysicists and cosmologists still don’t know how DE fits into the physical laws that govern the Universe. Candidates so far include a modification of Einstein’s general relativity (GR), the presence of a new field, or a cosmological constant (CC). As Dr. Visinelli told Universe Today via email:

“For this reason, dark energy is perhaps even more mysterious than dark matter. We are seeing the effects of dark energy across a number of observations, starting with the seminal work on 1A supernovae in as standard candles. Assuming that dark energy is indeed a field, the quanta associated with it would be extremely light and carry very little energy. This is the reason why very little work has been done on this type of searches.

Their work is based on new research that goes beyond the standard LCDM model of cosmology to consider that DE interacts with light by affecting its properties (i.e. polarization, color, direction ). However, these interactions could be subject to screening mechanisms that prevent local experiments from detecting them. In this model, it is predicted that dark energy quanta can be produced in the Sun.

XENON1T detector

The XENON1T detector, shown below. Credit: XENOX Collaboration

As Dr. Vagnozzi explained, the possible connection between screening and dark energy first came to him when he was taking a shower one day:

“I remember it was June 20 and I was taking a shower and thinking about solar axions (without) explaining XENON, and I realized the obvious solution was screening, because that would stop production in the denser stars. Screening is usually associated with patterns of dark energy and/or altered gravity, and there has been the “click”.

“I immediately Whatsapped Luca and we immediately started working on it (and reached out to our other co-authors who are experts in filtered dark energy/modified gravity patterns).”

For the purposes of their study, the team led by Dr. Vagnozzi and Dr. Visinelli reviewed data published by the XENON Collaboration, a DM research team made up of 135 researchers from 22 institutions around the world. At the heart of their experiment is a 3,500 kg (7,715 lb) detector of ultra-radio-pure liquid xenon housed in a 10 m (32.8 ft) tank of water. Located at the INFN Laboratori Nazionali del Gran Sasso, XENON is also the most sensitive dark matter (DM) experiment ever performed.

In 2020, the Collaboration published the results of its experimental campaign (2016 to 2018), which showed an unexpected rate of electronic recoil events. According to the collaboration, this did not constitute a detection of DM but could be explained by a tiny residual quantity of tritium in the experiment, the existence of a new particle (such as the solar axion), or an unexplained property of the neutrinos.

Upper PMT Matrix

The upper PMT network with all the electrical cables. Credit: XENON Dark Matter Project

For the purposes of their study, however, the team led by Vagnozzi and Visinelli speculated that this may have been the first direct detection of DE. Said Vagnozzi:

“In our model, dark energy has special properties: its mass term is related to the density of the environment, so denser materials would shield the effects of dark energy, while denser environments light such as intergalactic space would allow for long range dark energy.

“In this model called the ‘chameleon’, quanta of dark energy are produced in the region of the Sun in which the electromagnetic field is strongest, the tachocline, which is the region in which the transport of energy to the interior of the Sun changes from radiative to convection.The high energy density of the electromagnetic radiation in the region allows a strong coupling with the chameleon field and its production.

If true, this would mean that experiments around the world currently focused on dark matter research could also be devoted to the hunt for dark energy. To that end, Dr. Vagnozzi and Dr. Visinelli hope that this study will spark interest in particle models of ED and that the search for these elusive particles can be conducted in parallel with ongoing DM research. At the very least, these experiments will test theories about ED that go beyond the LCDM model, helping scientists narrow down the list of candidates. Says Dr. Visinelli:

“Many other experiments designed for Dark Matter may also contain information about these chameleons, and we hope that the design of future setups for this research will be considered. An independent test using cosmological data crossed with the predictions of the chameleon model would also be necessary. As for us, we plan to refine our paper’s calculations using a solar model, study chameleon production in massive stars, and get in touch with experimentalists for updates.

Illustris dark matter simulation

Illustris simulation, showing the distribution of dark matter in 350 million by 300,000 light-years. Galaxies are represented by high density white dots (left) and normal baryonic matter (right). Credit: Markus Haider/Illustris

In a recent paper, Dr. Vagnozzi and Dr. Visinelli conducted a study to examine whether pure elastic scattering between dark energy and baryonic (aka normal) matter could leave a visible imprint in cosmological observations. They determined that this was not likely, at least when applied to observations sensitive to the linear evolution of cosmic structure, such as the cosmic microwave background (CMB) and large-scale structure clustering. at the linear level.

However, Dr. Vagnozzi also works with a Ph.D. student in Munich to extend this study and predict the implications of DE interaction with normal matter. Specifically, they want to examine the effect this would have on the nonlinear clustering of the large-scale structure of the Universe, as well as the structure of galaxies and galaxy clusters. Coupled with large-scale surveys, which will benefit from next-generation telescopes in the years to come, astronomers and cosmologists could be on the verge of shedding light on the “Dark Universe!”

Originally published on Universe Today.

To learn more about this research, read XENON1T Experiment May Have Detected Dark Energy.

Reference: “Direct Dark Energy Detection: XENON1T Excess and Future Prospects” by Sunny Vagnozzi, Luca Visinelli, Philippe Brax, Anne-Christine Davis and Jeremy Sakstein, September 15, 2021, Physical examination D.
DOI: 10.1103/PhysRevD.104.063023

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Particle physics | Podcasts | Naked scientists https://polkinghorne.org/particle-physics-podcasts-naked-scientists/ Tue, 12 Oct 2021 07:00:00 +0000 https://polkinghorne.org/particle-physics-podcasts-naked-scientists/ We’re going to change gears slightly to talk about another type of mysterious particle, called a neutrino. Like an electron, but with no electrical charge and very small mass, neutrinos are one of the most abundant particles in the universe. But, because they interact very little with matter, they are incredibly difficult to detect. Nevertheless, […]]]>

We’re going to change gears slightly to talk about another type of mysterious particle, called a neutrino. Like an electron, but with no electrical charge and very small mass, neutrinos are one of the most abundant particles in the universe. But, because they interact very little with matter, they are incredibly difficult to detect. Nevertheless, understanding them better could lead to some of the answers we seek; but that means researchers like Summer Blot sometimes have to go to extraordinary lengths to study them, as she told Eva Higginbotham…

Summer – So IceCube is the biggest neutrino telescope in the world, and it’s super cool. It is actually buried in the glacier at the south pole of Antarctica

Eva – How does it work?

Summer – So neutrinos that come from, say, extraterrestrial sources, or even neutrinos that are produced here on earth, sort of travel through our body, but they also travel through this glacier. And so what we did with IceCube is we buried about 5,000 sensors in the glacier. They start about 1,500 meters below the surface and then go down another thousand meters, and basically these sensors are a total of one cubic kilometer of ice. And what they do is they pick up the light signals that are produced when a neutrino naturally interacts in the glacier anyway

Eva – So you basically have a huge piece of ice in which you have light sensors that you use to pick up things coming from space?

Summer – Yeah. A cubic kilometer of ice to measure subatomic particles from many, many, many millions of light-years away.

Eva – How do you place the sensors at 1,500 meters or whatever in a glacier?

Summer – That’s a great question, yes. There was actually a special drill that was built to build IceCube. And it works by heating the water and then shooting it very quickly and in a very controlled way into the glacier. So basically you melt the ice, deploy your sensors in the hole you just melted, and then you leave the water in the hole and it kind of freezes, so your sensors are literally frozen in the glacier himself.

Eva – So what’s the point of doing that in a glacier?

Summer – So the advantage is that the glacier just provides an incredibly large amount of material for neutrinos to interact with. The advantage for us is that the properties, the optical properties of ice, are just such that the light signals that neutrinos produce when they’ve interacted in the glacier, they can travel very, very long distances before being absorbed by the ice itself. So that gives us the ability, with our sensors, to pick up more information, more and more of these light signals from neutrino interactions with each event that happens. So when the neutrino interacts in the ice and tears the nucleus apart, it produces a shower of secondary particles and they travel in the same direction as the initial neutrino, and they are the ones that produce this kind of bluish light. This is called Cherenkov radiation. And our sensors are essentially instrumenting a three-dimensional grid in the ice, and so we’re essentially sampling that light as it’s produced along the path of the secondary particles. Then we measure how much light was produced and when it was produced, that’s what our sensors tell us, and so we can kind of trace back and kind of trace back, okay, here there was a signal, and then after that there was a signal, and after that… And so you can kind of draw a line between that almost and say, ah, okay, so the neutrino must be coming from that direction over there, and kind of point to the sky and say, is there something over there?

Eva – What have we found so far?

Summer – I would say the most exciting thing is really that these neutrinos from outer space exist. So when we built IceCube we thought they were out there, we thought all of our theories were saying, yeah, those neutrinos should be out there, but we hadn’t actually discovered them until we built IceCube. And at this point, we’ve detected enough of these neutrinos that it’s pretty well established that they exist and that there are extraterrestrial sources of extremely high energy neutrinos. So what we still don’t know exactly, you know, how they are produced or where they are produced. And we now have some clues that they might be from certain types of galaxies with black holes in the center, and lots of dust and stuff, and star formation going on in those galaxies, but we don’t really detected enough neutrinos yet to say, definitely, yes, those neutrinos come from that type of source and that’s how they’re produced. The plan, what we hope to do, is to go from one cubic kilometer to eight cubic kilometers inside the ice and then build an even larger network on the surface. This would basically allow us to detect even more neutrinos at even higher energies and really start making, what I would say, much more precise measurements of neutrino production in these very extreme remote sources

Eva – And you went to IceCube?

Summer – Honestly, this is my favorite place on the planet. It’s really different from any place I’ve been before, both in terms of natural beauty, it’s just a very flat ice cap, but somehow there’s beauty in there – at least for me! But also in terms of the kind of frontier spirit of, you know, a hundred people at a time, at most, living in a kind of little station, all working together for this one goal

Eva – It almost looks like you could go into space. I wonder, what are you eating there? What food is there?

Summer – So there is a greenhouse, which during the winter can be used to grow fruits and vegetables. Otherwise, a lot of really, really amazing food because – actually, I think Anthony Bourdain did an episode once at the South Pole because the food is so good. It’s quite expensive to fly, well, let’s say anyone or anything, to the South Pole. Thus, the cost of food then becomes negligible. So sometimes you eat lobster for dinner. Sometimes it’s steak. Sometimes it’s a nice cheese platter, you know, it’s, it’s really good food!

Eva – It’s like going to a place so expensive that they only give you very expensive things to eat!

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UNM’s QuarkNet Workshop at Explora Helps Educators Understand Particle Physics : UNM Newsroom https://polkinghorne.org/unms-quarknet-workshop-at-explora-helps-educators-understand-particle-physics-unm-newsroom/ Tue, 28 Sep 2021 07:00:00 +0000 https://polkinghorne.org/unms-quarknet-workshop-at-explora-helps-educators-understand-particle-physics-unm-newsroom/ The role of science in our everyday world has perhaps never been more important than in the past 18 months as a pandemic gripped the world. With that in mind, teaching the next generation of scientists is mission critical, and nurturing that interest in K-12 students is a key area for realizing big gains. It’s […]]]>

The role of science in our everyday world has perhaps never been more important than in the past 18 months as a pandemic gripped the world. With that in mind, teaching the next generation of scientists is mission critical, and nurturing that interest in K-12 students is a key area for realizing big gains. It’s a mission that the National Science Foundation (NSF) and the University of New Mexico take seriously.

QuarkNet, a nonprofit collaboration dedicated to developing America’s tech workforce, is an NSF-funded partnership between Fermilab and the University of Notre Dame that provides science teachers with the means to further develop their skills and to bring real research experience to classrooms across the United States.

Through a nationwide network of QuarkNet Centers, including the University of New Mexico, NSF brings together science teachers and academic researchers in active research projects in contemporary physics with focused hands-on workshops covering a variety of topics. in physics. Teachers gain experience in actual scientific research, maximizing their talents and effectiveness in the classroom; researchers achieve educational impact from their research and engagement with their local communities; and students immerse themselves in meaningful scientific research, preparing them for post-secondary education and developing essential intellectual skills.

At a recent workshop held in Albuquerque at the Explora Science Center & Childen’s Museum, QuarkNet staff Shane Wood led a group of teachers who traveled from Grants, Durango, Ft. Wingate, Roswell, Laguna-Acoma School and several in Albuquerque, including Public Academy of the Performing Arts, Desert Ridge Middle School, and Escuela del Sol Montessori, through a series of activities and experiences designed to help teachers bring real-world research experience in their classrooms.

“Our mission is really to work with teachers who, in turn, work with students. From this process, I think there are a lot of potential gains that we see happening,” said Wood, who works at the University of Notre Dame where NSF funds for QuarkNet are allocated. “We work on everything from researching our future particle physicists, who may not have known about it until they learned about it in their high school physics class, to simply having an appreciation and an informed taxpayer.

“I think the fact that students and therefore society in general have a better understanding of how science works really allows us to have a more informed public. We really have many goals along these roads, but our main mission is to work with teachers to then bring 21st century research experiences into the classroom.

“The idea is to help teachers become more aware, comfortable and interested in particle physics. We were happy to offer this workshop to all teachers of science, technology and mathematics , and that is precisely because particle physics is not so well known.” – Professor Sally Seidel, UNM Department of Physics and Astronomy

UNM’s QuarkNet program is led by Professor Sally Seidel of the Department of Physics and Astronomy. Seidel’s research interests include particle physics instrumentation and high energy collider physics. She is currently working on the Atlas experiment in high energy physics at the Large Hadron Collider, the largest and most powerful particle accelerator in the world. Seidel has coordinated QuarkNet activities at UNM since proposing a center and became the 48th QuarkNet member in 2016.

Events at the recent QuarkNet Workshop held at Explora included a presentation given by Seidel titled “The Beauty of Particle Physics”, a basic introduction to particle physics also known as high-energy physics, which studies the most small building blocks of nature. This particular field of science is a way to learn what the universe was like just seconds after it was born, billions of years before life existed to see it first hand.

Other activities included mixing the particle game, an activity based on particle maps describing the fundamental particles and their characteristics to become familiar with the Standard Model. Another fun activity was Rolling with Rutherford where the probe and target are a number of balls lined up in a row. The activity consists of rolling another marble in the aligned area. The data then consists of calculating the diameter of the target balls to use indirect measurements to determine a parameter. Teachers also took part in a real-time experiment to visualize particle tracks in a portable cloud chamber detector. The workshop also included a presentation on the LHC and what happens there.

“The idea is to help teachers be more aware, comfortable and interested in particle physics. We were happy to bring this to all science, technology and math teachers, and that’s precisely because particle physics is not so well known,” said Seidel, who enjoys helping people understand the technological implications of particle physics. “People like Shane and I partner with community engagement events like this to engage teachers and build this science education to try to help people understand the scientific description of the world.”

Previous QuarkNet@UNM activities have included a guided behind-the-scenes technical tour of the Very Large Array, a science heritage history tour at Los Alamos, and a high school workshop with a variety of presentations where students must be teachers themselves.

Turtle Haste, who has participated in QuarkNet twice at Desert Ridge Middle School in Albuquerque, enjoyed the workshop and thinks mentoring young students in STEM fields is imperative.

“It is extremely important. We come from a generation where there is a lot of bias against women in science,” Haste said. “It took me a long time to find someone who would take me in no matter what and get me through it. If I hadn’t had that mentor, I probably would have ended up being a secretary for that period. But because I had someone like, ‘Hey, you know what? You get this, let’s go. So I think it’s really important to mentor young students.

The Quarknet@UNM program is open to all New Mexico middle and high school teachers interested in gaining research experience. For more information, visit QuarkNet@UNM.

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A particle physics experiment could have directly observed dark energy https://polkinghorne.org/a-particle-physics-experiment-could-have-directly-observed-dark-energy/ Wed, 22 Sep 2021 07:00:00 +0000 https://polkinghorne.org/a-particle-physics-experiment-could-have-directly-observed-dark-energy/ About 25 years ago, astrophysicists noticed something very interesting about the Universe. The fact that it was expanding had been known since the 1920s, thanks to the observation of Edwin Hubble. But thanks to the observations that astronomers made with the space observatory that bore his name (the The Hubble Space Telescope), they began to […]]]>

About 25 years ago, astrophysicists noticed something very interesting about the Universe. The fact that it was expanding had been known since the 1920s, thanks to the observation of Edwin Hubble. But thanks to the observations that astronomers made with the space observatory that bore his name (the The Hubble Space Telescope), they began to notice how the rate of cosmic expansion was accelerating!

This led to the theory that the Universe is filled with an invisible and mysterious force, known as dark energy (DE). Decades after its proposal, scientists are still trying to pin down this elusive force that accounts for about 70% of the Universe’s energy budget. According to a recent study by an international team of researchers, the XENON1T experiment may have already detected this elusive force, opening new possibilities for future ED research.

The research was led by Dr Sunny Vagnozzi, a researcher at the Kavli Institute of Cosmology (KICC) at the University of Cambridge, and Dr Luca Visinelli, a Fellowship for Innovation (FELLINI) researcher (who is maintained with the support of the Marie Bourse Sklodowska-Curie) at the National Institute of Nuclear Physics (INFN) in Frascati, Italy. They were joined by researchers from the Institute for Theoretical Physics (IPhT), the University of Cambridge and the University of Hawaii.

Both DM and DE are part of the Lambda Cold Dark Matter (LCDM) model of cosmology, which posits that the Universe is filled with cold, slow-moving (DM) particles that interact with normal matter via the force of gravity alone. Lambda represents DE, which accelerates the expansion of the Universe. Since they are only discerned by observing their effect on the large-scale structure of the Universe, conventional thought holds that none of the forces interact with normal matter via electromagnetism or the weak or strong nuclear force. .

However, some DM theories posit that there is some level of interaction with visible matter, which researchers are actively testing. However, instead of more test results, astrophysicists and cosmologists still don’t know how DE fits into the physical laws that govern the Universe. Candidates so far include a modification of Einstein’s general relativity (GR), the presence of a new field, or a cosmological constant (CC). As Dr. Visinelli told Universe Today via email:

“For this reason, dark energy is perhaps even more mysterious than dark matter. We are seeing the effects of dark energy across a number of observations, starting with the seminal work on 1A supernovae in as standard candles. Assuming that dark energy is indeed a field, the quanta associated with it would be extremely light and carry very little energy. This is the reason why very little work has been done on this type of searches.

Their work is based on new research that goes beyond the standard LCDM model of cosmology to consider that DE interacts with light by affecting its properties (i.e. polarization, color, direction ). However, these interactions could be subject to screening mechanisms that prevent local experiments from detecting them. In this model, it is predicted that dark energy quanta can be produced in the Sun.

The XENON1T detector, shown below. Credit: XENOX Collaboration.

As Dr. Vagnozzi explained, the possible connection between screening and dark energy first came to him when he was taking a shower one day:

“I remember it was June 20 and I was taking a shower and thinking about solar axions (without) explaining XENON, and I realized the obvious solution was screening, because that would stop production in the denser stars. The screening is usually associated with dark energy and/or altered gravity patterns, and it just clicked.

I immediately WhatsApped Luca and we started working on it immediately (and reached out to our other co-authors who are experts in dark energy/modified gravity patterns).

For the purposes of their study, the team led by Dr. Vagnozzi and Dr. Visinelli reviewed data published by the XENON Collaboration, a DM research team made up of 135 researchers from 22 institutions around the world. At the heart of their experiment is a 3,500 kg (7,715 lb) detector of ultra-radio-pure liquid xenon housed in a 10 m (32.8 ft) tank of water. Located at the INFN Laboratori Nazionali del Gran Sasso, XENON is also the most sensitive dark matter (DM) experiment ever performed.

In 2020, the Collaboration published the results of its experimental campaign (2016 to 2018), which showed an unexpected rate of electronic recoil events. According to the collaboration, this did not constitute a detection of DM but could be explained by a tiny residual quantity of tritium in the experiment, the existence of a new particle (such as the solar axion), or an unexplained property of the neutrinos.

The upper PMT network with all the electrical cables. Credit: XENON Dark Matter Project

However, for the purposes of their study, the team led by Vagnozzi and Visinelli speculated that this may have been the first direct detection of DE. Said Vagnozzi:

“In our model, dark energy has special properties: its mass term is related to the density of the environment, so denser materials would shield the effects of dark energy, while denser environments light such as intergalactic space would allow for long range dark energy.

“In this model called “chameleon”, dark energy quanta are produced in the region of the Sun in which the electromagnetic field is strongest, the tachocline, which is the region in which the transport of energy to the interior of the Sun goes from the radiative transition to the convection.The high energy density of the electromagnetic radiation in the region allows a strong coupling with the chameleon field and its production.

If true, this would mean that experiments around the world currently focused on dark matter research could also be devoted to the hunt for dark energy. To that end, Dr. Vagnozzi and Dr. Visinelli hope that this study will spark interest in particle models of ED and that the search for these elusive particles can be conducted in parallel with ongoing DM research. At the very least, these experiments will test theories about ED that go beyond the LCDM model, helping scientists narrow the list of candidates. Says Dr. Visinelli:

“Many other experiments designed for Dark Matter may also contain information about these chameleons, and we hope that the design of future setups for this research will be considered. An independent test using cosmological data crossed with the predictions of the chameleon model would also be necessary. As for us, we plan to refine our paper’s calculations using a solar model, study chameleon production in massive stars, and get in touch with experimentalists for updates.

Illustris simulation, showing the distribution of dark matter in 350 million by 300,000 light-years. Galaxies are represented by high density white dots (left) and normal baryonic matter (right). Credit: Markus Haider/Illustris

In a recent paper, Dr. Vagnozzi and Dr. Visinelli conducted a study to examine whether pure elastic scattering between dark energy and baryonic (aka normal) matter could leave a visible imprint in cosmological observations. They determined that this was not likely, at least when applied to observations sensitive to the linear evolution of cosmic structure, such as the cosmic microwave background (CMB) and large-scale structure clustering. at the linear level.

However, Dr. Vagnozzi also works with a Ph.D. student in Munich to extend this study and predict the implications of DE interaction with normal matter. Specifically, they want to examine the effect this would have on the nonlinear clustering of the large-scale structure of the Universe, as well as the structure of galaxies and galaxy clusters. Coupled with large-scale surveys, which will benefit from next-generation telescopes in the years to come, astronomers and cosmologists could be on the verge of shedding light on the “dark universe”!

Further reading: physical examination D

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Steven Weinberg obituary | Particle physics https://polkinghorne.org/steven-weinberg-obituary-particle-physics/ Mon, 02 Aug 2021 07:00:00 +0000 https://polkinghorne.org/steven-weinberg-obituary-particle-physics/ The American theoretical particle physicist Steven Weinberg, who died at the age of 88, was one of the leading figures of the 20th century in this field. In 1979, he won a Nobel Prize for his work uniting two of nature’s fundamental forces, which became a foundation of the Standard Model of particle physics, the […]]]>

The American theoretical particle physicist Steven Weinberg, who died at the age of 88, was one of the leading figures of the 20th century in this field. In 1979, he won a Nobel Prize for his work uniting two of nature’s fundamental forces, which became a foundation of the Standard Model of particle physics, the theory that describes all known particles and fundamental forces in the universe. .

From Weinberg’s prodigious work – in research, in his technical and popular books on quantum field theory and cosmology, and in scientific commentary articles – his work demonstrating that the transmutation of elements by the weak nuclear force is fundamentally related to electromagnetism constituted a truly remarkable breakthrough.

Following Peter Higgs’ discovery in 1964 that fundamental particles can, in theory, gain mass through the “Higgs mechanism”, he, Weinberg and others tried to find examples where this mechanism is used in the nature. These attempts initially focused on the strong force that binds atomic nuclei, but no consistent correspondence emerged, until 1967, while on his way to work at MIT (the Massachusetts Institute of Technology), Weinberg had an inspired thought: they had implemented the right idea. , but to the wrong problem.

Instead of the strong force, Weinberg realized that the mechanism could apply to the weak nuclear force, manifested by radioactivity. As a bonus, Weinberg realized that thanks to this application, he could describe in a single mathematical diagram both the phenomena of electromagnetism and the form of radioactivity which is the key to the creation of elements in stars. This idea would become the basis of the current standard model of particles and forces.

A viable quantum field theory of electromagnetism – quantum electrodynamics (QED) – had been known since 1947. The key to its consistency was that the photon – the basic particle of electromagnetic radiation – is massless. Weinberg’s marriage of weak and electromagnetic forces required the existence of analogues of the photon. These “W and Z bosons” were later discovered and confirmed to be very massive, as Weinberg had predicted.

There was a problem, however: being massive, they apparently undermined the mathematical coherence of the theory. Weinberg conjectured, but was unable to prove, that if the W and Z gained their masses through the Higgs mechanism, his extension of QED would indeed be a viable quantum theory of two forces.

Initially his paper had little impact, with one prominent scientist later describing the response: “Rarely has such a great achievement been so widely ignored.” Then, in 1971, a young Dutch student, Gerard ‘t Hooft, proved the model to be a complete and viable theory, winning himself a Nobel Prize in 1999 for this feat.

With the demonstration that Weinberg had indeed constructed a coherent relativistic quantum theory of electromagnetic and weak force fields, the predictions of which were soon confirmed in a variety of experiments, his seminal paper quickly became the most cited in all of theoretical physics. Its implications were so profound that they determined the direction of high-energy particle physics during the last decades of the 20th century. In what was to prove to be of momentous importance, his papers drew attention to a cornerstone of his theoretical construction – the necessary role of the ‘Higgs boson’. The search for this particle would take four decades; its discovery in 2012 was the final piece in a structure whose architectural design owed much to the genius of Weinberg.

Born in New York, Steven was the son of Jewish immigrants, Eva (née Israel) and Frederick Weinberg, a court stenographer. Steven’s love for science began in childhood with the gift of a chemistry set. He attended Bronx Science High School, which produced eight Nobel laureates, including Weinberg’s contemporary Sheldon Glashow, whose freelance work led him to share the 1979 prize with Weinberg and Abdus Salam. He earned a bachelor’s degree at Cornell University in 1954, and that year married Louise Goldwasser, whom he had met while a student; she became a law professor. After a year at what is now the Niels Bohr Institute in Copenhagen, Weinberg returned to the United States and Princeton University, where he earned a doctorate (1957).

After two years at Columbia University and six at Berkeley, in 1966 Weinberg joined Harvard University, first as a lecturer, and from 1973 as a professor of physics. Early in his Harvard stint, Weinberg had a joint appointment at MIT, and it was while driving there in his red Camarro that he had his weak nuclear force epiphany.

In 1982 he moved to the University of Texas at Austin, where he spent the rest of his career. He never retired and continued teaching until the spring of that year.

For decades, Weinberg’s ideas outside of his 1967 paper inspired new lines of research. His work on “effective field theories” redefined the direction of work in quantum field theory and influenced attempts to find a viable quantum theory of gravity. He was one of the founders of the concept of “chiral perturbation theory” as a mathematical approach to understanding aspects of the strong nuclear force.

In addition to these seminal research contributions, Weinberg wrote an influential text on gravitation, a masterful three-volume set of textbooks on quantum field theory, and authored the popular best-selling cosmology book The First Three Minutes (1977).

In 1992 he published Dreams of a Final Theory, which has become a classic discourse on the goal of fundamental physics at the dawn of the 21st century.

In his later years he became an authoritative historian of science, his gravity and wisdom making him a respected commentator on science policy as well as social issues, and making him one of the most respected figures in science. world.

He is survived by his wife, Louise, whom he married in 1954, their daughter, Elizabeth, and one granddaughter.

Steven Weinberg, theoretical physicist, born May 3, 1933; passed away on July 23, 2021

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Argonne aurora will accelerate particle physics discoveries at CERN https://polkinghorne.org/argonne-aurora-will-accelerate-particle-physics-discoveries-at-cern/ Thu, 22 Jul 2021 07:00:00 +0000 https://polkinghorne.org/argonne-aurora-will-accelerate-particle-physics-discoveries-at-cern/ July 22, 2021 – The U.S. Department of Energy’s (DOE) Argonne National Laboratory will house one of the nation’s first exascale supercomputers when Aurora arrives in 2022. To prepare code for the architecture and System-wide, 15 research teams are taking part in the Aurora Early Science program through the Argonne Leadership Computing Facility (ALCF), a […]]]>

July 22, 2021 – The U.S. Department of Energy’s (DOE) Argonne National Laboratory will house one of the nation’s first exascale supercomputers when Aurora arrives in 2022. To prepare code for the architecture and System-wide, 15 research teams are taking part in the Aurora Early Science program through the Argonne Leadership Computing Facility (ALCF), a DOE Office of Science user facility. With access to pre-production time on the supercomputer, these researchers will be among the first in the world to use an exascale machine for science.

Early philosophers first formulated the idea of ​​the atom around the fifth century BCE. And just when we thought we had understood its basic structure – protons, neutrons and electrons – theories and technologies emerged to prove us wrong. It turns out that there are still more fundamental particles, like quarks, bound together by aptly named gluons.

Physicists discovered many of these and other particles in the huge beasts of machinery we call colliders, helping to develop what we know today as the Standard Model of physics. But there are questions that keep nagging: is there something even more fundamental? Is the standard model all there is?

Determined to find out, the high-energy physics community is working to integrate ever larger colliders and more sophisticated detectors with exascale computing systems. Among them is Walter Hopkins, assistant physicist at Argonne National Laboratory and collaborator on the ATLAS experiment at CERN’s Large Hadron Collider (LHC), near Geneva, Switzerland.

In collaboration with researchers from Argonne and Lawrence Berkeley National Lab, Hopkins is leading an Aurora Early Science Program project through the ALCF to prepare software used in LHC simulations for exascale computing architectures, including the upcoming exascale machine d ‘Argonne, Aurora. With a trillion calculations per second, Aurora is at the frontier of supercomputing and at the height of the next particle physics challenge of gargantuan scale.

The project was started several years ago by physicist and Argonne Emeritus James Proudfoot, who saw the distinct advantages of exascale in enhancing the impact of such complex science.

Align the codes on the new architecture

The collisions produced in the LHC occur in one of the many detectors. The one the team is focusing on, ATLAS, witnesses billions of particle interactions every second and the new particle signatures these collisions create in their wake.

One type of code the team is focusing on, called event generators, simulates the underlying physical processes that occur at interaction points in the 17-mile-circumference collider ring. Aligning the physics produced by the software with that of the Standard Model helps researchers accurately simulate collisions and predict the types, trajectories and energies of residual particles.

Detecting physics in this way creates a mountain of data and requires equally significant computational time. And now CERN is upping the ante as it prepares to upgrade the LHC’s luminosity, enabling more particle interactions and a 20-fold increase in data output.

As the team looks to Aurora to handle this increase in its simulation needs, the machine is not without some challenges.

Workers inside ATLAS, one of several primary detectors at CERN’s Large Hadron Collider. ATLAS witnesses a billion particle interactions every second and the signatures of new particles created in proton-proton collisions at near light speed. (Picture: CERN)

Until recently, event generators ran on computer processors (central processing units). Although they work fast, a processor can usually only perform several operations at a time.

Aurora will feature both CPUs and GPUs (graphics processing units), the choice of gamers around the world. GPUs can handle many operations by breaking them up into thousands of smaller tasks spread across many cores, the engines that drive both types of units.

But it takes a lot of effort to move CPU-based simulations to GPUs efficiently, Hopkins notes. So making this move to prepare for both Aurora and the onslaught of new LHC data presents several challenges, which have become a central part of the team’s goal.

“We want to be able to use Aurora to help us meet these challenges,” says Hopkins, “but that forces us to study computing architectures that are new to us and our code base. For example, we focus on a generator used in ATLAS, called MadGraph, which runs on GPUs, which are more parallel and have different memory management requirements.

A particle interaction simulation code, MadGraph, has been written by an international team of high-energy physics theorists and meets the simulation needs of the LHC.

Simulation and AI support experimental work

The LHC has played an important role in bringing the predictions to fruition. Even more famously, the Standard Model predicted the existence of the Higgs boson, which imparts mass to all fundamental particles; ATLAS and its counterpart detector, CMS, confirmed the existence of Higgs in 2012.

But, as is often the case in science, big discoveries can lead to more substantial questions, many of which are not predicted by the Standard Model. Why does the Higgs have the mass it is? What is dark matter?

“The reason for this very large LHC upgrade is that we hope to find that needle in the haystack, that we will find an anomaly in the dataset that offers a hint of physics beyond the Standard Model,” says Hopkins. .

A combination of computing power, simulation, experience, and artificial intelligence (AI) will greatly aid this research by providing accuracy in both prediction and identification.

When the ATLAS detector witnesses these particle collisions, for example, it records them as electronic signals. These are reconstructed in the form of pixels of bursts of energy which can correspond to the passage of an electron.

“But just like in AI, where the canonical example identifies cats and dogs in images, we have algorithms that identify and reconstruct those electronic signals into electrons, protons, and other things,” says Taylor Childers, computer scientist at the ALCF, member of the team. .

Data reconstructed from real crash events is then compared to simulated data to look for differences in patterns. This is where the accuracy of the physical models comes in. If they perform well and the real and simulated data do not match, you continue to measure and eliminate anomalies until it is likely that you found that needle, that something that doesn’t fit the standard pattern.

The team is also using AI to quantify uncertainty, to determine the likelihood that they have correctly identified a particle.

Humans are able to identify particles to a limited extent – several parameters like moment and position could tell us that a certain particle is an electron. But base that characterization on 10 interrelated parameters, then that’s another story altogether.

“This is where artificial intelligence really shines, especially if these input parameters are correlated, like the momentum of the particles around an electron and the momentum of the electron itself,” says Hopkins. “These correlations are hard to deal with analytically, but because we have so much simulation data, we can teach artificial intelligence and it can tell us, it’s an electron with this probability because I have all this information from Entrance. “

Exascale computing and the way forward

In preparation for Aurora, the team continues to work on programming languages ​​for new architectures and code to run on Intel hardware that will be used on Aurora, as well as hardware from other vendors.

“Part of the R&D we do with our partner Intel is to make sure the hardware does what we expect it to do and does it efficiently,” says Childers. “Having a machine like Aurora will give us lots of computing power and lots of nodes to effectively reduce solution time, especially when we move to the upgraded LHC.”

The solution is an answer to a fundamental question: is there more beyond the standard model? — and one that could have repercussions unimaginable a hundred years from now, Hopkins notes.

“Basic research can give us knowledge that can lead to societal transformation, but if we don’t do research, it won’t lead anywhere,” he says.

The ALCF is a DOE Office of Science user facility.

Funding for this project was provided by the DOE Office of Science: Offices of High Energy Physics and Advanced Scientific Computing Research. ATLAS is an international collaboration supported by the DOE.

About the ALCF

The Argonne Leadership Computing Facility provides supercomputing capabilities to the scientific and engineering community to advance fundamental discovery and understanding across a wide range of disciplines. Supported by the Advanced Scientific Computing Research (ASCR) program of the U.S. Department of Energy’s (DOE) Office of Science, the ALCF is one of two DOE advanced computing facilities dedicated to open science.

Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation’s first national laboratory, Argonne conducts cutting-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state, and municipal agencies to help them solve their specific problems, advance American scientific leadership, and prepare the nation for a better future. With employees in more than 60 countries, Argonne is managed by UChicago Argonne, LLC for the US Department of Energy’s Office of Science.

The U.S. Department of Energy’s Office of Science is the largest supporter of basic physical science research in the United States and works to address some of the most pressing challenges of our time. For more information, visit https://​ener​gy​.gov/​s​c​ience.

Click here to find out more.


Source: JOHN SPIZZIRRI, ALCF

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Brookhaven Lab Appoints New Director of Nuclear and Particle Physics Branch https://polkinghorne.org/brookhaven-lab-appoints-new-director-of-nuclear-and-particle-physics-branch/ Thu, 15 Apr 2021 07:00:00 +0000 https://polkinghorne.org/brookhaven-lab-appoints-new-director-of-nuclear-and-particle-physics-branch/ Haiyan Gao, nuclear physicist and professor, will join the lab as associate lab director for nuclear and particle physics UPTON, NY – Haiyan Gao, currently the Henry W. Newson Professor Emeritus of Physics at Duke University, will join the U.S. Department of Energy’s Brookhaven National Laboratory as Associate Laboratory Director (ALD) for Nuclear Physics and […]]]>

Haiyan Gao, nuclear physicist and professor, will join the lab as associate lab director for nuclear and particle physics

UPTON, NY – Haiyan Gao, currently the Henry W. Newson Professor Emeritus of Physics at Duke University, will join the U.S. Department of Energy’s Brookhaven National Laboratory as Associate Laboratory Director (ALD) for Nuclear Physics and particles (NPP) from or around June 1, 2021.

Gao, who has a long background in nuclear physics, will help develop Brookhaven’s collective long-term vision for the next 10 years. She will also work throughout the lab and beyond to develop her emerging expertise at the future Electron-Ion Collider (EIC), a one-of-a-kind nuclear physics research facility to be built at the lab over the next decade after Brookhaven’s flagship nuclear physics facility, the Relativistic Heavy Ion Collider, completes its research mission.

“The Nuclear and Particle Physics Branch is internationally well-known in the fields of accelerator science, high-energy physics and nuclear physics,” Gao said. “I am very excited about the opportunity and the impact that I will be able to have in collaboration with many people at the Lab.”

Gao will replace ALD Deputy for High Energy Physics Dmitri Denisov, who became interim NPP ALD after Berndt Mueller left office last year to return to teaching and research full-time at Duke.

“We are delighted to welcome Haiyan to Brookhaven at such an exciting time for nuclear and particle physics,” said Brookhaven Laboratory Director Doon Gibbs. “His perspective and experience will be instrumental in advancing science here in the lab and beyond.”

Gao joins Brookhaven Lab as he develops the EIC in collaboration with scientists at the DOE’s Thomas Jefferson National Accelerator Facility. The EIC will offer scientists a deeper look at the building blocks of visible matter and the most powerful force in nature.

“What’s important in the end is that we really deliver the science,” she said.

The facility is one that the nuclear physics community has been campaigning for for many years, to work towards a more complete understanding of nucleons and atomic nuclei in quantum chromodynamics, the physical theory that describes strong interactions, Gao noted. . It will also allow scientists to discover new physics beyond the Standard Model of particle physics, Gao said.

“This facility also gives us a wonderful opportunity to train a highly motivated scientific and technical workforce in this country,” she added.

In addition to his expertise in nuclear physics, Gao has a keen interest in promoting diversity, equity and inclusion in science.

Gao obtained his doctorate. in physics from the California Institute of Technology in 1994. Since then, she has held several positions in the field, including as assistant physicist at Argonne National Laboratory and assistant and associate professor of physics at Massachusetts Institute of Technology.

While at Duke, Gao also served as the Founding Professor of Physics and Vice Chancellor for Academic Affairs at Duke Kunshan University in Kunshan, China, where she spent some of her childhood years.

Gao’s research interests at Duke have included the structure of the nucleon, the search for exotic states of quantum chromodynamics, fundamental studies of low-energy symmetry to search for new physics beyond the standard model of electroweak interactions, and the development of polarized targets.

She was elected a Fellow of the American Physical Society in 2007 and won the U.S. Department of Energy’s Best Junior Researcher Award in 2000.

Brookhaven National Laboratory is supported by the US Department of Energy’s Office of Science. The Office of Science is the largest supporter of basic physical science research in the United States and works to address some of the most pressing challenges of our time. For more information, visit https://energy.gov/science.

Follow @BrookhavenLab on Twitter or find us on Facebook.

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Is the Standard Model of Particle Physics really Kaput? https://polkinghorne.org/is-the-standard-model-of-particle-physics-really-kaput/ Thu, 15 Apr 2021 07:00:00 +0000 https://polkinghorne.org/is-the-standard-model-of-particle-physics-really-kaput/ Lately the internet has been flooded with stories about the Standard Model of particle physics having been broken. These stories stem from a recent experiment by physicists at Fermilab in Illinois, where a group of scientists discovered that muons “twerk.” Well, sort of. Don’t worry if you don’t know what a muon is, you’ll find […]]]>

Lately the internet has been flooded with stories about the Standard Model of particle physics having been broken.

These stories stem from a recent experiment by physicists at Fermilab in Illinois, where a group of scientists discovered that muons “twerk.” Well, sort of. Don’t worry if you don’t know what a muon is, you’ll find out in a moment, and if you don’t know what twerking is, try Googling Miley Cyrus.

Muons are electrically charged particles, which means that when placed in a magnetic field, they begin to spin. Their rotation frequency is determined by the muon’s interactions with other particles and forces – this is called its g-factor.

Just as the Earth oscillates on its axis as it spins, a muon’s axis of rotation also oscillates. Twenty years ago, scientists at Brookhaven National Laboratory first measured the g-factor and muon oscillation, and they found values ​​that did not match predictions made by the Standard Model. The Brookhaven data came in at 3 sigma, or three standard deviations.

Last week, Fermilab’s G-2 experiment, which is still ongoing, concluded that muons gliding around their magnetized ring were wobbling more than originally. The group’s conclusions reached the level of 4.2 sigma, which is very close to the magical 5 sigma which corresponds to a 1 in 3.5 million chance that the data is statistical chance. Physicists regard 5-sigma as irrefutable proof of a discovery.

The question then is, “What gives muons that extra push that makes them wobble?” One explanation is that they are pushed by virtual particles that appear and disappear due to quantum fluctuations.

Virtual particles appear in pairs – one of matter and one of antimatter. An example is an electron and its antimatter counterpart, a positron. If the muons are jostled around by virtual pairs of particles that are part of the standard model, so much the better, but what if the muons are affected by a pair of unknown virtual particles? This question is what keeps physicists awake at night.

What is the standard model?

The standard model of particle physics is the set of equations that describe the 17 known elementary particles. Elementary particles are particles that are not composed of other particles.

Prior to their discovery, the Standard Model predicted the existence and properties of W and Z bosons, the gluon, and top and charm quarks. The Standard Model also predicted the existence of the Higgs boson, which we will encounter in a minute.

The Standard Model began to take shape in 1897, when English physicist JJ Thomson discovered the electron, and it was not considered complete until 2012, when scientists at CERN’s Large Hadron Collider discovered the boson. of Higgs.

The graph below displays the particles composing the standard model. They are divided into fermions and bosons, with the 12 fermions being divided into six quarks and six antiquarks, and six leptons and antileptons.

The standard model of particle physics Source: Wikimedia Commons/Marcia Wendorf

Quarks

What sets quarks apart is that they have something called color charge, which causes them to interact via the strong force. Quarks can combine in two ways:

1. A quark and an antiquark, called meson.
2. Three quarks, called a baryon. The lightest baryons are the proton and the neutron.

Quarks also have electric charge and weak isospin, which means they can interact with each other through electromagnetism and weak interaction.

Standard model of elementary particles
Standard model of elementary particles Source: MissMJ, Cush/Wikimedia Commons

leptons

Leptons do not carry a color charge, so they do not respond to the strong force. Three of the leptons, the electron, the muon and the tau, carry an electric charge and thus interact electromagnetically with other particles. Three of the leptons, the neutrinos, carry no electrical charge, which means they only respond to the weak force. This makes them very difficult to detect.

Generations of Fermions

Just as generations of people are made up of grandparents, parents, and children, fermions also come in generations, with both members of a succeeding generation having greater mass than a previous generation.

In the table above, the first generation of quarks is made up of up and down quarks, the second generation is made up of charm and strange quarks, and the third generation is made up of top and bottom quarks.

First generation charged particles do not decay, which is a good thing since protons and neutrons are composed of at the top and down quarks, which are first-generation quarks. Second and third generation fermions decay, which means they have very short half-lives. A half-life is the time it takes for half of a sample to decay.

Last-generation fermions can only be observed in very high-energy environments, such as the Large Hadron Collider. Neutrinos invade our universe and the three generations do not decay. However, neutrinos are very difficult to detect because they almost never interact with matter.

gauge bosons

Our universe has four fundamental forces: electromagnetism, strong force, weak force and gravity. Now, for bad news, the standard model can’t account for gravity, so for now, we’ll ignore it.

The Standard Model explains the other three forces as resulting from particles exchanging other particles, the effect being that the force influences both particles. This is why gauge bosons are called force-mediator particles.

The electromagnetic force is transmitted between electrically charged particles by the photon, which has no mass. The weak force is transmitted between quarks and leptons by gauge bosons W+, W− and Z. These are massive particles, the Z boson being more massive than the W±.

Now get ready for a headache: the W± bosons act on either left-handed particles or right-handed antiparticles, while the electrically neutral Z boson interacts with both left-handed particles and antiparticles.

W± bosons carry an electric charge of +1 and -1, and they couple to the electromagnetic interaction, so when grouped with photons they collectively mediate what is called the electroweak interaction.

There are eight gluons which transmit the strong force among the six quarks. Gluons are massless, and because they themselves have a color charge, they can interact with each other.

The Higgs boson

The video of Peter Higgs, 83, taking out his handkerchief and wiping his eyes at the July 4, 2012 announcement at CERN that, finally, the Higgs boson had been discovered is truly moving. Higgs theorized the particle in 1964.

The Higgs boson generates the lepton, electron, muon and tau masses, and the quark masses. It does not generate mass for the photon and gluon, and since the Higgs boson itself is massive, that means it has to interact with itself.

Not only is the Higgs boson massive, with a mass of about 125 GeV/c2, or about 133 proton masses, but it decays almost immediately once created. This means that the Higgs can only be created and observed in a very high energy particle accelerator. Before it was observed at CERN, scientists at Fermilab were looking for the Higgs.

A year after the discovery of the Higgs boson, in 2013, Peter Higgs is finally honored with a Nobel Prize in Physics, alongside François Englert. On the day of the announcement, Higgs wanted to avoid media attention, so he walked out. He didn’t own a cell phone, so he only found out he had won the Nobel Prize when he met a neighbor.

Is the standard model really outdated?

Just last month, new scientist reported that Large Hadron Collider scientists found a deviation from the predicted rates at which particles containing the bottom quark decay into an electron and a muon. While the production of electrons and muons should be equal, this is not the case.

Other problems not explained by the standard model include:

  • Does the Higgs boson also give mass to neutrinos?
  • About 95% of the universe is not made of ordinary matter but consists of dark energy and dark matter that does not fit into the Standard Model.
  • The gluons that transmit the force of gravity have never been found.
  • Baryon asymmetry.
  • Neutrino oscillations and nonzero masses.
  • Why is the universe expanding faster and faster?
  • Why is the universe made up of more matter than antimatter?

The next two years will determine whether the Standard Model is still a correct representation of our universe, or whether it will need to be modified or abandoned altogether. Whatever happens, it’s going to be one hell of a ride.

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