Wasikul Islam, a postdoctoral researcher with Sau Lan Wu’s group
For this award, postdocs write a short article that describes their research for the general public. Interested postdocs apply to submit an article, then receive guidelines and editorial assistance to improve accessibility. Approved articles are posted on the WISL website, and the author receives a $250 award.
Islam’s article, “Navigating Anomalies in the Pursuit of New Physics” shares how particle physicists study the fundamental building blocks of the universe, exploring the complex behaviors of subatomic particles that shape our world.
“As a postdoctoral researcher, my journey is not limited to research alone,” Islam says in the article. “It comes with an important responsibility to share the wonders and experiences of scientific research with diverse communities.”
The dual mission of the Wisconsin Initiative for Science Literacy is to promote literacy in science, mathematics and technology among the general public and to attract future generations to careers in research, teaching and public service. WISL is directed by Professor Bassam Z. Shakhashiri of the University of Wisconsin-Madison Chemistry Department. Programs draw on the concepts developed by Dr. Shakhashiri during many years of innovative work in science education.
Federal physics advisory panel — including Profs. Bose and Cranmer — announces particle physics recommendations
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Earlier this year, physics professors Tulika Bose and Kyle Cranmer were selected to serve on the Particle Physics Project Prioritization Panel, or P5, a group of High Energy Physics experts that advises the Department of Energy Office of Science and the National Science Foundation’s Division of Physics on high energy and particle physics matters.
One recommendation is to move forward with a planned expansion of the IceCube Neutrino Observatory, an international scientific collaboration operated by the UW–Madison at the South Pole. Other recommendations include support for a separate neutrino experiment based in Illinois (the Deep Underground Neutrino Experiment, or DUNE); continuing investment in the Large Hadron Collider in Switzerland and the Rubin Observatory in Chile; and expanding involvement in the Cherenkov Telescope Array (CTA), a ground-based very-high-energy gamma ray observatory. UW–Madison physicists have leading roles in all of these research efforts.
Additional recommendations include the development of a next generation of ground-based telescopes to observe the cosmic microwave background and a direct dark matter detector experiment, among others.
Wasikul Islam honored with UW Postdoc Association Excellence in Service Award
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Wasikul Islam, a postdoc in Sau Lan Wu’s group, was recognized by the UW–Madison Postdoc Association with an Excellence in Service Award. He was nominated for his science outreach activities, promotion of basic sciences, volunteering and mentorship to undergrad Physics students through various non-profit organizations including the American Physical Society.
The Postdoc Excellence Awards recognize current postdocs on the UW-Madison campus that contribute their time, knowledge, energy, and enthusiasm to mentoring, teaching, and service. They were established to encourage and reward excellence, innovation, and effectiveness in the mentoring, teaching, and service of UW-Madison postdocs. The 2023 winners were honored at the Celebration of Postdoc Excellence on May 19.
Wasikul Islam receives his award at the 2023 Celebration of Postdoc Excellence, held May 19.
Department of Energy grant to train students at the interface of high energy physics and computer science
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To truly understand our physical world, scientists look to the very small, subatomic particles that make up everything. Particle physics generally falls under the discipline of high energy physics (HEP), where higher and higher energy collisions — tens of teraelectronvolts, or about ten trillion times the energy of visible light — lead to the detection and characterization of particles and how they interact.
These collisions also lead to the accumulation of inordinate amounts of data, and HEP is increasingly becoming a field where researchers must be experts in both particle physics and advanced computing technologies. HEP graduate students, however, rarely enter graduate school with backgrounds in both fields.
Physicists from UW–Madison, Princeton University, and the University of Massachusetts-Amherst are looking to address the science goals of the HEP experiments by training the next generation of software and computing experts with a 5-year, ~$4 million grant from the U.S. Department of Energy (DOE) Office of Science, known as Training to Advance Computational High Energy Physics in the Exascale Era, or TAC-HEP.
“The exascale era is upon us in HEP and the complexity, computational needs and data volumes of current and future HEP experiments will increase dramatically over the next few years. A paradigm shift in software and computing is needed to tackle the data onslaught,” says Tulika Bose, a physics professor at UW–Madison and TAC-HEP principal investigator. “TAC-HEP will help train a new generation of software and computing experts who can take on this challenge head-on and help maximize the physics reach of the experiments.”
Tulika Bose
In total, DOE announced $10 million in funding today for three projects providing classroom training and research opportunities in computational high energy physics to train the next generation of computational scientists and engineers needed to deliver scientific discoveries.
At UW–Madison, TAC-HEP will annually fund four-to-six two-year training positions for graduate students working on a computational HEP research project with Bose or physics professors Keith Bechtol, Kevin Black, Kyle Cranmer, Sridhara Dasu, or Brian Rebel. Their research must broadly fit into the categories of high-performance software and algorithms, collaborative software infrastructure, or hardware-software co-design.
Bose’s research group, for example, focuses on proton-proton collisions in the Compact Muon Solenoid (CMS) at the CERN Large Hadron Collider (LHC). The high luminosity run of the LHC, starting in 2029, will bring unprecedented physics opportunities — and computing challenges, challenges that TAC-HEP graduate students will tackle firsthand.
“The annual data volume will increase by 30 times while the event reconstruction time will increase by nearly 25 times, requiring modernization of the software and computing infrastructure to handle the demands of the experiments,” Bose says. “Novel algorithms using modern hardware and accelerators, such as Graphics Processing Units, or GPUs, will need to be exploited together with a transformation of the data analysis process.”
TAC-HEP will incorporate targeted coursework and specialized training modules that will enable the design and development of coherent hardware and software systems, collaborative software infrastructure, and high-performance software and algorithms. Structured R&D projects, undertaken in collaboration with DOE laboratories (Fermilab and Brookhaven National Lab) and integrated within the program, will provide students from all three participating universities with hands-on experience with cutting-edge computational tools, software and technology.
The training program will also include student professional development including oral and written science communication and cohort-building activities. These components are expected to help build a cohort of students with the goal of increasing recruitment and retention of a diverse group of graduate students.
“Future high energy physics discoveries will require large accurate simulations and efficient collaborative software,” said Regina Rameika, DOE Associate Director of Science for High Energy Physics. “These traineeships will educate the scientists and engineers necessary to design, develop, deploy, and maintain the software and computing infrastructure essential for the future of high energy physics.
Higgs @ Ten: UW–Madison physicists’ past and future roles
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Ten years ago, on July 4, 2012, the CMS and ATLAS collaborations at the Large Hadron Collider (LHC) at CERN — including many current and former UW–Madison physicists — announced they had discovered a particle that was consistent with predictions of the Higgs boson.
In the ten years since, scientists have confirmed the finding was the Higgs boson, but its discovery opened more avenues of discovery than it closed. Now, with the LHC back up and running, delivering proton collisions at unprecedented energies, high energy physicists are ready to investigate even more properties of the particle.
The Higgs discovery was published in Physics Letters B and received the cover
“The Higgs plays an incredibly important role in particle physics,” says Kevin Black, who previously worked on ATLAS before joining the UW–Madison physics department and is now part of CMS. “But for being such a fundamental particle, for giving mass to all elementary particles, for being deeply connected to flavor physics and why we have different generations of matter particles — we know a relatively small amount about it.”
Finding the Higgs particle had been one of the main goals of the LHC. The particle was first theorized by physicist Peter Higgs (amongst others, but his name was forever associated with it) in the 1960s.
“The basic idea was that if you just had electromagnetic and strong interactions, then the theory would have been fine if you just put a mass in by hand for the elementary particles,” explains Black. “The weak interaction spoils that, and it was a big question at the time of whether or not the whole structure of particle physics and of quantum field theory were actually going to be consistent.”
Higgs and others realized that there was a way to make it happen if they introduced a new field, which then became the Higgs field and the Higgs particle, that can interact with all other matter and give particles their mass. The Higgs particle, however, eluded experimental observation, leaving a gap in the Standard Model. In retrospect, one of the difficulties was that the mass of the Higgs — around 125 GeV — was much larger than the technology at the time could reach experimentally.
In earlier generations of experiments, UW–Madison physicist Sau Lan Wu participated in searches using the ALEPH experiment that placed a strong lower bound on the mass of the Higgs boson. Also at UW–Madison, Duncan Carlsmith, Matthew Herndon and their groups participated in searches at the CDF experiment that placed an upper bound on the mass of the Higgs boson and saw evidence of Higgs production in the region of mass where it was finally discovered.
Wesley Smith shows the electronics of the trigger system which led to the discovery of the Higgs Boson. Smith led the team that designed and developed the trigger system.
This research set the stage for the experiments that were perfectly designed to discover the Higgs boson: the world’s most powerful hadron collider, the LHC, and the most capable pair of high energy collider experiments ever built, CMS and ATLAS.
The UW–Madison CMS group had three major projects: the trigger project led by Wesley Smith (now emeritus faculty), and the end cap muon system led by Don Reeder (now emeritus faculty) and Dick Loveless (now emeritus scientist), and a computing project led by Sridhara Dasu, who is current head of the group. Having made essential detector contributions, the UW–Madison CMS group, including Herndon, moved on to Higgs hunting and the discoveries. The group, now bolstered by the addition of Black and Tulika Bose to the physics department faculty, continues the work of understanding the Higgs Boson thoroughly.
The UW–Madison ATLAS group, founded and led by Wu, is an important leader of Higgs physics. The group is fortunate to attract another important leader of ATLAS, Higgs physicist Kyle Cranmer, who recently joined UW–Madison as physics department faculty and the director of the American Family Data Science Institute.
Both CMS and ATLAS announced the discovery, made separately but concurrently, in 2012. When it was first discovered, it conformed to expected energies and momentum of the Higgs, but finding it in this rare decay mode was unexpected, so LHC scientists called it the Higgs-like particle for a while.
The UW–Madison ATLAS group at CERN at the time of the Higgs discovery all celebrated with printouts of the data confirming 5sigma. | Provided by Sau Lan Wu
At 3:00pm [on June 25, 2012], there was a commotion in the Wisconsin corridor on the ground floor of CERN Building 32. My graduate student Haichen Wang was saying loudly, ‘Haoshuang is going to announce the Higgs discovery!’ Our first reaction was that it was a joke; thus when we entered Haoshuang’s office, we all had smiles on our faces. Those smiles suddenly became much bigger when we got to look at the result of Haoshuang’s combination: It showed the 5.08s close to the Higgs mass of 125GeV/c2. Pretty soon, cheers were ringing down the Wisconsin corridor.
ATLAS had a discovery!”
The Higgs-like announcement from ten years ago has since been confirmed to be the Higgs particle. Several years later, Dasu’s group’s work saw the Higgs decay into the tau, and provided the first evidence of the particle coupling to matter particles, not just to bosons.
Sau Lan Wu and other Higgs scientists were featured on the cover of the New York Times for a story about the chase for the Higgs boson.
On the ten-year anniversary, both ATLAS and CMS collaborations published summaries of their findings to date and future directions. Experimental questions still being addressed include continuing to measure higher-precision interactions between the Higgs and particles it has already been observed to interact with, and detecting previously-unobserved interactions between the Higgs and other particles.
“One big question that immediately comes to my mind is the mass problem. The breakthrough generated by the Higgs discovery was that elementary particles acquire their masses through the Higgs particle,” Wu writes in her Physics Today essay. “A deeper question that needs to be answered is how to explain the values of the individual masses of the elementary particles. In my mind, this mass problem remains a big topic to be explored in the years to come.”
“Another one of the big things that we’re looking for in future data is to understand Higgs potential,” Black says. “Right now, by measuring the mass, we’ve only measured right around its ground state, and that has great implications for the stability of our universe.”
Also on the ten-year anniversary, CERN announced that the LHC — which had been shut down for three years to work on upgrades — was ready to again start delivering proton collisions at an unprecedented energy of 13.6 TeV in its third round of runs. It is expected that the ATLAS and CMS detectors will record more collisions in this upcoming run than in the previous two combined.
The LHC program is scheduled to run through 2040, and the UW–Madison scientists who are part of the CMS and ATLAS collaborations will almost certainly continue to play key roles in future discoveries.
UW–Madison’s current CMS collaboration members include Kevin Black, Tulika Bose, Sridhara Dasu, and Matthew Herndon, and their research groups. Current ATLAS collaboration members include Kyle Cranmer and Sau Lan Wu and their research groups.
Brian Rebel promoted to full professor
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Brian Rebel
The Department of Physics is happy to announce that Professor Brian Rebel has been promoted to full professor.
Rebel is a high energy experimentalist whose research focuses on accelerator-based neutrino physics. He joined the department as an associate professor with a joint appointment at Fermilab in 2018, where he is now a senior scientist.
“Professor Rebel is a leader in neutrino science, making major contributions to DUNE experiments and having published recently on four different neutrino collaborations,” says Mark Eriksson, physics department chair. “The department is thrilled about his promotion to full professor.”
Rebel has established himself as a leader in the Long-Baseline Neutrino Facility (LBNF) and Deep Underground Neutrino Experiment (DUNE). DUNE is an international experiment for neutrino science and proton decay studies that consists of two neutrino detectors — one near Fermilab in Illinois, and one in South Dakota. The experiment will be installed in LBNF, which will produce the neutrino beam. Rebel is currently the DUNE Anode Plane Assembly (APA) consortium manager, and has previously led Fermilab’s DUNE Science Group.
Since 2005, Rebel has also been involved in Fermilab’s NOvA experiment, which uses precision measurements to investigate the flavor oscillations of neutrinos that are not predicted by the Standard Model. He is currently serving as the co-convener of the analysis group searching for oscillations of active neutrino flavors into a sterile neutrino.
Rebel is currently training three graduate students and two postdoctoral scholars, and expects to graduate his first UW–Madison doctoral student soon. Additionally, he supervised several trainees at Fermilab before he came to UW–Madison. He has enjoyed teaching both introductory physics as well as physics courses for non-majors, and is an effective and engaging teacher.
Congrats, Prof. Rebel, on this well-deserved recognition!
Sau Lan Wu honored with named planet
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The International Astronomical Union (IAU) has named a minor planet ‘Saulanwu’ after UW–Madison physics professor Sau Lan Wu.
The planet (177770) ‘Saulanwu’ (=2005 JE163) was discovered on May 8, 2005 at Mt Lemmon observatory in southern Arizona by a NASA funded project, the Catalina Sky Survey. More details about the planet can be found from NASA’s JPL website, including a sketch of the planet’s orbit, which is in the asteroid belt between Mars and Jupiter. Minor planet ‘Saulanwu’ is about two kilometers in diameter, and it takes four years to orbit the sun once. This planet is relatively stable, dynamically, and is expected to remain in our cosmos for millions of years to come.
Wu was nominated for this honor by astronomer Gregory J. Leonard from the University of Arizona’s Department of Planetary Sciences.
Keith Bechtol selected to Department of Energy Early Career Research Program
The funding will allow Bechtol and his group to first work on commissioning the Vera C. Rubin Observatory in preparation for the Legacy Survey of Space and Time (LSST), then they will transition to data collection and analysis for their cosmology research.
“We are anticipating that LSST will catalog more stars, more galaxies and more solar system objects during its first year of operations than all previous telescopes combined,” Bechtol says.
Rubin Observatory’s telescope will have an eight-meter diameter mirror and a ten square degree field of view. The 3.2-billion-pixel camera will collect an image every 30 seconds. All told, LSST will amass around 10 terabytes of data every night.
Bechtol has leadership roles for building and commissioning the observatory as well as with the Dark Energy Science Collaboration (DESC), the international science collaboration that will make high accuracy measurements of fundamental cosmological parameters using LSST data. At least seven other collaborations have formed around different science areas to analyze the data. Rubin Observatory is preparing to serve the LSST data to many thousands of scientists in the US, Chile, and at international partner institutions around the world.
“DESC will use LSST data to address several outstanding physics questions, such as: Why are the distances between galaxies growing at an accelerating rate? What is the fundamental nature of dark matter? What is the absolute mass scale of neutrinos? How did the universe begin and what were the initial conditions?” Bechtol says.
Bechtol will receive around $150,000 per year for five years to cover summer salary and research expenses. The research expenses will be used mostly to cover the analyses after the data collection starts. However, because there cannot be useful data without the initial commissioning and science validation steps — and because the Observatory is still a couple of years away from first light — the DOE award is also supporting Bechtol’s efforts during the commissioning phase to accelerate the realization of DESC science goals.
“For me, the most important thing about this award is that it will provide more opportunity for students and postdocs to directly contribute to this ambitious experiment. Turning on a new experiment of this scale and complexity doesn’t happen every day,” Bechtol says. “For my research group to be able to participate firsthand in the commissioning, seeing first light, and contributing to the first cosmology results is so valuable from a career development perspective. We are training the next generation of experiment builders.”
The DOE early career program is open to untenured, tenure-track professors at a U.S. academic institution (or a full-time employee at a DOE national laboratory) who received a PhD within the past 10 years. Research topics are required to fall within one of the DOE Office of Science’s eight major program offices, including high energy physics, the program through which Bechtol’s award was made.
Sridhara Dasu named a member of the International Committee on Future Accelerators
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High energy physicist Sridhara Dasu was recently named a member of the International Committee for Future Accelerators (ICFA), a term he’ll serve for three years. ICFA was created to facilitate international collaboration in the construction and use of accelerators for high energy physics. The Committee has 16 members, selected primarily from the regions most deeply involved in high-energy physics. Dasu will be representing the United States on the committee.
Study of high-energy particles leads PhD student Alex Wang to Department of Energy national lab
In 2012, scientists at CERN’s Large Hadron Collider announced they had observed the Higgs boson particle, verifying many of the theories of physics that rely on its existence.
Alex Wang
Since then, scientists have continued to search for the properties of the Higgs boson and for related particles, including an extremely rare case where two Higgs boson particles appear at the same time, called di-Higgs production.
“We’ve had some searches for di-Higgs right now, but we don’t see anything significant yet,” said Alex Wang, a PhD student in experimental high energy physics at UW–Madison. “It could be because it doesn’t exist, which would be interesting. But it also could just be because, according to the Standard Model theory, it’s very rare.”
Wang will have a chance to aid in the search for di-Higgs production in more ways than one. Starting in November, he will spend a year at the SLAC National Accelerator Laboratory as an awardee in the Department of Energy Office of Science Graduate Student Research Program.
The program funds outstanding graduate students to pursue thesis research at Department of Energy (DOE) laboratories. Students work with a DOE scientist on projects addressing societal challenges at the national and international scale.
At the SLAC National Accelerator Laboratory, Wang will primarily work on hardware for a planned upgrade of the ATLAS detector, one of the many detectors that record properties of collisions produced by the Large Hadron Collider. Right now, ATLAS collects an already massive amount of data, including some events related to the Higgs boson particle. However, Higgs boson events are extremely rare.
In the future, the upgraded High-Luminosity Large Hadron Collider (HL-LHC) will enable ATLAS to collect even more data and help physicists to study particles like the Higgs boson in more detail. This will make it more feasible for researchers to look for extremely rare events such as di-Higgs production, Wang said. The ATLAS detector itself will also be upgraded to adjust for the new HL-LHC environment.
“I’m pretty excited to go there because SLAC is essentially where they’ll be assembling the innermost part of the ATLAS detector for the future upgrade,” Wang said. “So, I think it’s going to be a really central place in the future years, at least for this upgrade project.”
Increasing the amount of data a sensor collects can also cause problems, such as radiation damage to the sensors and more challenges sorting out meaningful data from background noise. Wang will help validate the performance of some of the sensors destined for the upgraded ATLAS detector.
“I’m also pretty excited because for the data analysis I’m doing right now, it’s mainly working in front of a computer, so it will be nice to have some experience working with my hands,” Wang said.
At SLAC, he will also spend time searching for evidence of di-Higgs production.
Wang’s thesis research at UW–Madison also revolves around the Higgs boson particle. He sifts through data from the Large Hadron Collider to tease out which events are “signals” related to the Higgs boson, versus events that are “backgrounds” irrelevant to his work.
One approach Wang uses is to predict how many signal events researchers expect to see, and then determine if the number of events recorded in the Large Hadron Collider is consistent with that prediction.
“If we get a number that’s consistent with our predictions, then that supports the existing model of physics that we have,” Wang said. “But for example, if you see that the theory predicts we’d have 10 events, but in reality, we see 100 events, then that could be an indication that there’s some new physics going on. So that would be a potential for discoveries.”
The Department of Energy formally approved the U.S. contribution to the High-Luminosity Large Hadron Collider accelerator upgrade project earlier this year. The HL-LHC is expected to start producing data in 2027 and continue through the 2030s. Depending on what the future holds, Wang may be able to use data from the upgraded ATLAS detector to find evidence of di-Higgs production. If that happens, he also will have helped build the machine that made it possible.
