particle accelerator – Polkinghorne http://polkinghorne.org/ Tue, 22 Feb 2022 00:16:45 +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 particle accelerator – Polkinghorne http://polkinghorne.org/ 32 32 The Absolutely Incredible Theory of Almost Everything https://polkinghorne.org/the-absolutely-incredible-theory-of-almost-everything/ Sat, 15 Jan 2022 08:00:00 +0000 https://polkinghorne.org/the-absolutely-incredible-theory-of-almost-everything/ How does our world work at the subatomic level? The standard model. What a boring name for the most accurate scientific theory known to human beings. More than a quarter of the Nobel Prizes in Physics of the last century are direct inputs or direct results of the Standard Model. Still, its name suggests that […]]]>

How does our world work at the subatomic level?

The standard model. What a boring name for the most accurate scientific theory known to human beings.

More than a quarter of the Nobel Prizes in Physics of the last century are direct inputs or direct results of the Standard Model. Still, its name suggests that if you can afford a few extra bucks a month, you should buy the upgrade. As a theoretical physicist, I would prefer The Absolutely Incredible Theory of almost anything. That’s what the standard model really is.

Many remember the enthusiasm of scientists and the media over the 2012 discovery of the Higgs boson. But this high-profile event didn’t come out of nowhere — it capped a five-decade unbeaten streak for the standard model. All fundamental forces except gravity are included. All attempts to overthrow it to demonstrate in the laboratory that it needs substantial reworking – and there have been many over the past 50 years – have failed.

In short, the standard model answers this question: what is it all made of and how does it fit together?

The smallest building blocks

You know, of course, that the world around us is made of molecules, and molecules are made of atoms. Chemist Dmitri Mendeleev discovered in the 1860s how to arrange all of the atoms – aka the elements – in the periodic table that you probably studied in college. But there are 118 different chemical elements. There’s antimony, arsenic, aluminum, selenium… and 114 others.

Periodic table

But these elements can be broken down further. Credit: Ruben Vera Koster

Physicists like simple things. We want to boil things down to their essence, a few basics. More than a hundred chemical elements is not simple. The ancients believed that everything was made up of only five elements: earth, water, fire, air and ether. Five is much simpler than 118. It’s also wrong.

In 1932, scientists knew that all these atoms were made up of only three particles: neutrons, protons and electrons. Neutrons and protons are tightly bound in the nucleus. Electrons, thousands of times lighter, whirl around the nucleus at speeds close to the speed of light. The physicists Planck, Bohr, Schroedinger, Heisenberg and their friends had invented a new science – quantum mechanics – to explain this movement.

It would have been a satisfying place to stop. Just three particles. Three is even easier than five. But how to hold together? Negatively charged electrons and positively charged protons are bound by electromagnetism. But the protons are all packed into the nucleus, and their positive charges should powerfully push them away. Neutrons can’t help.

What binds these protons and these neutrons? “Divine intervention” a man told me on a Toronto street corner; he had a pamphlet, I could read all about it. But this scenario seemed to pose a lot of problems, even for a divine being – to keep an eye on every one of the 108° protons and neutrons in the universe and bend them to his will.

Expand the Particle Zoo

Meanwhile, nature has cruelly refused to limit its particle zoo to just three. Really four, because you would have to count the photon, the particle of light described by Einstein. Four changed to five when Anderson measured electrons with a positive charge – positrons – hitting Earth from space. At least Dirac had predicted these first antimatter particles. Five became six when the pawn, which Yukawa believed would hold the core together, was found.

Then came the muon – 200 times heavier than the electron, but otherwise a twin. “Who ordered this? II Rabi joked. That sums it all up. Number seven. Not only not simple, redundant.

In the 1960s, there were hundreds of “fundamental” particles. Instead of the neatly organized periodic table, there were only long lists of baryons (heavy particles like protons and neutrons), mesons (like Yukawa pions) and leptons (light particles like the electron and the elusive neutrinos) – with no organization and no guiding principles.

Into this breach has slipped the standard model. It wasn’t an overnight flash of brilliance. No Archimedes jumped out of a bathtub shouting “eureka”. Instead, there was a series of crucial ideas from a few key people in the mid-1960s that turned this quagmire into a simple theory, and then five decades of experimental verification and theoretical elaboration.

Standard model of elementary particles

The standard model of elementary particles provides a list of ingredients for everything around us. Credit: National Fermi Accelerator Laboratory

Quarks. They come in six varieties which we call flavors. Like ice cream, except it’s not as tasty. Instead of vanilla, chocolate and so on, we have high, low, weird, charm, low and high. In 1964, Gell-Mann and Zweig taught us the recipes: mix and match three quarks to get a baryon. Protons are two ups and one down quark bound together; neutrons are two lows and one high. Choose a quark and an antiquark to get a meson. A pion is an up or down quark bound to an anti-up or an anti-down. All the material of our daily life is composed only of quarks, anti-quarks and electrons.

Simple. Well, it’s simple, because keeping those quarks bound is a feat. They are so closely related to each other that you never find a single quark or antiquark. The theory of this binding, and the particles called gluons (laughs) that are responsible for it, is called quantum chromodynamics. It is an essential piece of the standard model, but mathematically difficult, even posing an unsolved problem of basic mathematics. We physicists do our best to calculate with it, but we are still learning how.

The other aspect of the standard model is “a lepton model”. It’s the name of Steven Weinberg’s landmark 1967 paper that brought together quantum mechanics with the essential knowledge of how particles interact and organized the two into a single theory. He incorporated the familiar electromagnetism, associated it with what physicists called “the weak force” that causes certain radioactive decays, and explained that they were different aspects of the same force. It incorporated the Higgs mechanism to give mass to fundamental particles.

Since then, the Standard Model has predicted the results of experiment after experiment, including the discovery of several varieties of quarks and W and Z bosons, heavy particles that are to weak interactions what the photon is to electromagnetism. The possibility that neutrinos are not massless was overlooked in the 1960s, but slipped easily into the Standard Model in the 1990s, a few decades later.

CERN particle accelerator Higgs boson decay SM

3D view of an event recorded at the CERN particle accelerator showing the expected characteristics of the decay of the SM Higgs boson into a pair of photons (dashed yellow lines and green towers). Credit: McCauley, Thomas; Taylor, Lucas; for the CMS CERN collaboration

Discovering the Higgs boson in 2012, long predicted by the Standard Model and long sought after, was a thrill but not a surprise. It was yet another crucial victory for the Standard Model over the dark forces that particle physicists have repeatedly warned were looming on the horizon. Concerned that the Standard Model did not adequately embody their expectations of simplicity, worried about its mathematical consistency, or anticipating the possible need to incorporate the force of gravity, physicists made numerous proposals for theories beyond of the norm. Model. These go by exciting names like Grand Unified Theories, Supersymmetry, Technicolor, and String Theory.

Unfortunately, at least for their proponents, theories beyond the Standard Model have not yet successfully predicted a new experimental phenomenon or an experimental divergence from the Standard Model.

After five decades, far from needing an upgrade, the Standard Model deserves to be celebrated as an absolutely incredible theory of almost everything.

Written by Glenn Starkman, Distinguished University Professor of Physics, Case Western Reserve University.

This article first appeared in The Conversation.The conversation

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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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Wobbling in the history of particle physics – now. Powered by Northrop Grumman https://polkinghorne.org/wobbling-in-the-history-of-particle-physics-now-powered-by-northrop-grumman/ Mon, 18 Oct 2021 07:00:00 +0000 https://polkinghorne.org/wobbling-in-the-history-of-particle-physics-now-powered-by-northrop-grumman/ Particle physics is the quest to discover the fundamental components of the universe by analyzing, cataloging and measuring the particles that combine to create everything. It’s no easy task – the variety and variability of these physical firmaments makes them an ever-changing puzzle that can seem completely impenetrable until a new secret is unlocked. Now, […]]]>

Particle physics is the quest to discover the fundamental components of the universe by analyzing, cataloging and measuring the particles that combine to create everything. It’s no easy task – the variety and variability of these physical firmaments makes them an ever-changing puzzle that can seem completely impenetrable until a new secret is unlocked.

Now, new research on the muon – a small electron-like particle 200 times heavier than its negatively charged cousin – could pave the way for the particle’s next pivot: oscillations.

Standard operation procedure

To help make sense of the universe and how it works, scientists created the Standard Model. It was not an easy task either. As SciTechDaily notes, while the electron was discovered in 1897, the last element in the current framework – the Higgs boson – wasn’t confirmed until 2012.

The model makes it possible to reconcile three of the four fundamental forces: electromagnetism, the strong nuclear force and the weak nuclear force. It also highlights the role of quarks and leptons as the building blocks of all matter, including the familiar trio of protons, neutrons and electrons. Work on the Standard Model has shown that photons play a role in the transport of electromagnetism, while the strong force relies on gluons to ensure the stability of atomic nuclei and the weak force exploits W and Z bosons. to drive the powerful nuclear processes that keep stars burning for billions of years. year.

However, despite its usefulness, the standard model has a blind spot: gravity. While the model does an excellent job of describing which particles underlie the other three fundamental forces, gravity is conspicuously absent. This is because scientists have never been able to link a specific particle to the creation and distribution of gravity. While it plays a vital role in the workings of our universe – whether it’s counteracting the expansive tendencies of nuclear reactions within our sun or keeping our feet firmly planted on planet Earth – this apparently appealing operation simple has historically resisted deep understanding.

But new muon measurements could change all that.

Crack the code

What is important to remember from scientists – and particle physicists in particular – is that they are never satisfied with the status quo. Although the Standard Model provides a starting point for understanding the universe, obvious shortcomings in the current framework mean there is still work to be done. In practice, this work involves finding new approaches to potentially breaking the model by conducting experiments, taking measurements, and then comparing the results to what the model predicts.

The challenge? For years, the model has found the right answers, much to the frustration of physicists who know something is missing. Repeated experiments using different particle approaches have produced precise measurement after precise measurement – ​​so far. Recent follow-up work on earlier muon experiments using more advanced equipment suggests a crack in the current model and raises hope that scientists may finally have found the key to a new revolution in particle physics.

Meet the muon

So what exactly is a muon? Think electron, but heavier. Much heavier – 200 times heavier, in fact. As Science Daily notes, muons and electrons “are essentially tiny magnets with their own magnetic field.” However, unlike electrons, muons are much less stable, existing only a few millionths of a second before decaying. It is also difficult to observe muons, even during their brief stay here, because the vacuum they occupy is not empty.

“It’s your cappuccino-foam version of a vacuum, where there are virtual particles appearing and disappearing all the time,” Lawrence Gibbons, who led the Cornell team involved in the new research, told Science Daily. “And that turns out to affect the strength of a muon’s magnetic field.”

Through work at CERN in 1959, followed by more precise experiments in 1966 and 1969, and then another round at Brookhaven National Laboratory in 1999, the researchers finally found something: a disconnect between the observed magnetic measurements and predicted when the muons made their way into this void. New efforts at Fermilab with more precise and advanced equipment have confirmed these findings – and could pave the way for a much more massive muon impact.

Let’s Get Physics-al

Work at CERN, Brookhaven and Fermilab all focus on the same thing: the g-2 value of the muon, which represents the amount it “wobbles” via vacuum interactions. As Jessica Esquivel, a particle physicist at Fermilab, notes, this oscillation is called the precession frequency.

“When muons enter a magnetic field, they precess or spin like a top,” she told Vox.

To measure precession, efforts at Fermilab used a powerful particle accelerator – capable of creating 20 times more muons than those previously used at CERN – to shoot an intense beam of muons into highly sensitive detectors, which measured their precession frequency. As the Standard Model predicts, this precession occurs when muons collide with virtual particles, which Esquivel describes as “a kind of ghosting of real particles.”

“We have photons going in and out and they’re just kind of like there, but not really there,” she told Vox. However, despite this recurring strangeness, these virtual particles have a physical impact on muon oscillations.

But this is where it gets really weird: Experiments at Fermilab confirm that muons flicker more than they should, according to the Standard Model. Even more exciting? Scientists don’t know why.

Stumbling our way forward

The lack of certainty here is what makes these experimental results so interesting. According to the Standard Model, g-2 muon values ​​are explainable using actual particle interactions and should produce predictable results. However, Fermilab’s efforts suggest that something else is causing this additional oscillation – something outside the current functional framework, as Esquivel and his colleagues told Vox.

And while there have been discussions about this “breaking” of the Standard Model before, it’s more about filling in the details where the data was clearly missing. Esquivel likens it to adding elements to the periodic table.

“Even back then,” she tells Vox, “they had places where they knew an item had to go, but they hadn’t been able to see it yet. That’s basically where we are now. In practice, this movement of muons opens the door to a multitude of potential operations on the particles.This unexpected oscillation could be caused by an interaction with dark matter or long-predicted dark energy particles, or it could help establish a particle-based link with the peripheral fourth fundamental gravitational force.

Esquivel simply explains the impact of this measurement of movement: “It’s once in a lifetime. We are looking for new physics and we are so close that we can taste it. A meal of muons, an extra oscillation – it happens!

Being at the forefront of change, especially in space, physics and engineering, has been part of the Northrop Grumman culture for generations. Click here to search for jobs in these areas of scientific innovation.

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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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University receives 6 million euros for experimental particle physics https://polkinghorne.org/university-receives-6-million-euros-for-experimental-particle-physics/ Mon, 06 Sep 2021 07:00:00 +0000 https://polkinghorne.org/university-receives-6-million-euros-for-experimental-particle-physics/ © CERN/M. Hoch The German government has allocated 6.25 million euros of funds for research on experimental particle physics over the next three years, the University of Hamburg announced on Monday (August 30, 2021). The funds will benefit research by Hamburg-based scientists at the European Particle Physics Laboratory (CERN) in Geneva. The focus is on […]]]>

© CERN/M. Hoch

The German government has allocated 6.25 million euros of funds for research on experimental particle physics over the next three years, the University of Hamburg announced on Monday (August 30, 2021). The funds will benefit research by Hamburg-based scientists at the European Particle Physics Laboratory (CERN) in Geneva. The focus is on particle collisions at the Large Hadron Collider, the most powerful particle accelerator in the world.

Research at CERN

“The funds will provide tremendous support for our particle physics research at the Large Hadron Collider,” said Professor Peter Schleper, who leads the research at the University of Hamburg in Geneva. The funds allow the university’s working group to continue its activities in the Compact Muon Solenoid (CMS) experiment at CERN, where collisions of heavy atoms are studied with a particle detector and unearth so far unknown particles. In 2012, the discovery of the Higgs particle, known as the “God particle”, proved to be CMS’s greatest success to date.

University of Hamburg seeks new insights into particle physics

“We want to study the Higgs particle in more detail and address pressing questions about dark matter. CMS data offer fascinating possibilities,” said Professor Johannes Haller from the Institute for Experimental Physics at the University of Hamburg. Next spring, a new data collection period will begin at the Large Hadron Collider, which could provide particularly interesting insights into the smallest building blocks of matter. Hamburg-based scientists are already developing components for the reconstruction of the Large Hadron Collider scheduled for 2025, which will further increase the performance of the particle accelerator.

The German Ministry of Education and Research funds the participation of German researchers in the CMS experiment as part of a Germany-wide research program involving the University of Hamburg, the Deutsches Elektronen- Synchrotron (DESY), the RWTH University of Aachen, the Karlsruhe Institute of Technology and the CASUS Institute in Görlitz.

tn/sb/pb

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Muons don’t fit the standard model of particle physics https://polkinghorne.org/muons-dont-fit-the-standard-model-of-particle-physics/ Fri, 16 Apr 2021 07:00:00 +0000 https://polkinghorne.org/muons-dont-fit-the-standard-model-of-particle-physics/ Share this Item You are free to share this article under the Attribution 4.0 International License. Fundamental particles called muons behave in ways that scientists’ best theory to date, the Standard Model of particle physics, does not predict, the researchers report. The discovery comes from early results from the Muon g-2 experiment at the US […]]]>

Fundamental particles called muons behave in ways that scientists’ best theory to date, the Standard Model of particle physics, does not predict, the researchers report.

The discovery comes from early results from the Muon g-2 experiment at the US Department of Energy’s Fermi National Accelerator Laboratory.

“This experience is a bit like a detective novel.”

This historic result confirms a discrepancy that has plagued researchers for decades.

The strong evidence that muons deviate from the Standard Model calculation could hint at some exciting new physics. The muons in this experiment act as a window into the subatomic world and could interact with as yet unknown particles or forces.

“This experiment is a bit like a detective novel,” says team member David Hertzog, a University of Washington physics professor and founding spokesperson for the experiment. “We analyzed data from the inaugural Muon g-2 test at Fermilab and discovered that the Standard Model alone cannot explain what we found. Something else, perhaps beyond the standard model, may be required. »

A muon is about 200 times more massive than its cousin the electron. They occur naturally when cosmic rays hit the Earth’s atmosphere. Fermilab’s particle accelerators can produce large numbers of them. Like electrons, muons act as if they have a small internal magnet. In a strong magnetic field, the direction of the muon magnet precedes, or “wobbles,” much like the axis of a spinning top. The strength of the internal magnet determines the muon’s precession rate in an external magnetic field and is described by a number known as the g-factor. This number can be calculated with ultra-high precision.

As muons flow through the Muon g-2 magnet, they also interact with a “quantum foam” of subatomic particles that appear and disappear. Interactions with these short-lived particles affect the value of the g-factor, causing muon precession to accelerate or slightly slow down. The standard model predicts with great accuracy what the value of this “abnormal magnetic moment” should be. But if the quantum foam contains additional forces or particles not accounted for by the Standard Model, it would further alter the g-factor of the muon.

Hertzog, then at the University of Illinois, was a lead scientist in the previous experiment at Brookhaven National Laboratory. This attempt ended in 2001 and offered clues that the behavior of the muon did not conform to the Standard Model. The new measurement from the Muon g-2 experiment at Fermilab strongly agrees with the value found at Brookhaven and deviates from theory with the most accurate measurement to date.

The accepted theoretical values ​​for the muon are:

  • g-factor: 2.00233183620(86)
  • abnormal magnetic moment: 0.00116591810(43)

The new experimental global mean results announced today by the Muon g-2 collaboration are:

  • g-factor: 2.00233184122(82)
  • abnormal magnetic moment: 0.00116592061(41)

The combined results from Fermilab and Brookhaven show a difference with theoretical predictions at a significance of 4.2 sigma, a little short of the 5 sigma – or 5 standard deviations – that scientists prefer as a claim of discovery. But it’s still compelling evidence of new physics. The probability that the results are a statistical fluctuation is approximately 1 in 40,000.

“This result from the first run of the Fermilab Muon g-2 experiment is arguably the most anticipated result in particle physics in recent years,” says Martin Hoferichter, assistant professor at the University of Bern and member of the theoretical collaboration that predicts the value of the standard model. “After almost a decade, it’s great to see this massive effort finally come to fruition.”

The Fermilab experiment, which is underway, reuses the main component of the Brookhaven experiment, a superconducting magnetic storage ring 50 feet in diameter. In 2013, it was transported 3,200 miles by land and sea from Long Island to suburban Chicago, where scientists were able to take advantage of Fermilab’s particle accelerator and produce the states’ most intense muon beam. -United. Over the next four years, researchers mounted the experiment; tuned and calibrated an incredibly uniform magnetic field; developed new techniques, instruments and simulations; and thoroughly tested the entire system.

The Muon g-2 experiment sends a beam of muons into the storage ring, where they circulate thousands of times at near the speed of light. Detectors lining the ring allow scientists to determine how fast muons “wobble”.

Many Fermilab sensors and detectors have been built at the University of Washington, such as instruments to measure the muon beam as it enters the storage ring and to detect the telltale particles that appear when the muons decay . Dozens of scientists – including professors, postdoctoral researchers, technicians, graduate students and undergraduates – worked to assemble these sensitive instruments, then set them up and monitor them at Fermilab.

“The outlook for the new result has triggered a coordinated theoretical effort to provide our experimental colleagues with a robust and consensus prediction of the Standard Model,” says Hoferichter. “Future runs will motivate further refinements, to enable a conclusive statement whether physics beyond the Standard Model lurks in the muon’s anomalous magnetic moment.”

In its first year of operation, 2018, the Fermilab experiment collected more data than all previous muon g-factor experiments combined. The Muon g-2 collaboration has now completed the analysis of the movement of more than 8 billion muons from this first period.

Analysis of data from the second and third cycles of the experiment is in progress; the fourth is in progress and a fifth is planned. Combining the results from all five tests will give scientists an even more precise measurement of the muon’s ‘wobble’, revealing with greater certainty whether new physics is lurking in the quantum foam.

“So far, we’ve analyzed less than 6% of the data the experiment will eventually collect,” says Fermilab scientist Chris Polly, who is a co-spokesperson for the current experiment and was a graduate student. of the University of Illinois under Hertzog during the Brookhaven Experiment. “While these early results tell us there is an intriguing difference to the standard model, we will learn much more over the next two years.”

“With these exciting results, our team, especially our students, are excited to push hard on analyzing the remaining data and taking future data to achieve our ultimate goal of accuracy,” says Peter Kammel, research professor of physics at the University of Washington.

An article on the research appears in Physical examination letters. Hertzog will present the findings at a University of Washington Physics Department Symposium on April 12.

The Muon g-2 experiment is an international collaboration between Fermilab in Illinois and more than 200 scientists from 35 institutions in seven countries.

Source: University of Washington

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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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Have we just discovered new physics? These theoretical physicists don’t think so https://polkinghorne.org/have-we-just-discovered-new-physics-these-theoretical-physicists-dont-think-so/ Mon, 12 Apr 2021 07:00:00 +0000 https://polkinghorne.org/have-we-just-discovered-new-physics-these-theoretical-physicists-dont-think-so/ When the results of an experiment don’t match the predictions made by the best theory of the day, something is wrong. Fifteen years ago, physicists from Brookhaven National Laboratory discovered something puzzling. Muons – a type of subatomic particle – were moving in unexpected ways that did not match theoretical predictions. Was the theory wrong? […]]]>

When the results of an experiment don’t match the predictions made by the best theory of the day, something is wrong.

Fifteen years ago, physicists from Brookhaven National Laboratory discovered something puzzling. Muons – a type of subatomic particle – were moving in unexpected ways that did not match theoretical predictions. Was the theory wrong? Was the experiment interrupted? Or, temptingly, was this evidence of new physics?

Since then, physicists have been trying to solve this mystery.

A group of Fermilab addressed the experimental component and on April 7, 2021, published the results confirming the original measurement. But my colleagues and I took a different approach.

I am a theoretical physicist and the spokesperson and one of the two coordinators of the Budapest-Marseille-Wuppertal partnership. This is a large-scale collaboration of physicists who tried to see if the old theoretical prediction was incorrect. We used a new method to calculate how muons interact with magnetic fields.

My team’s theoretical prediction is different from the original theory and matches both old experimental evidence and new Fermilab data. If our calculation is correct, it resolves the gap between theory and experiment and would suggest that there is not an undiscovered force of nature.

Our result was published in the journal Nature on April 7, 2021, the same day as the new experimental results.