Jonathan D. Moreno to Give Milchberg Lecture on April 4

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Category: Department News

Published: Friday, March 17 2023 01:40

Jonathan D. Moreno,  the David and Lyn Silfen University Professor at the University of Pennsylvania, will give the third Irving and Renee Milchberg Endowed Lecture at 4 p.m. in room 1410 of the John S. Toll Physics Bldg. The talk is free and open to the public, with refreshments served at 3:30 p.m. 

Moreno's talk will address Bioethics and the Rules-Based International Order.   Jonathan Moreno. Credit: University of Pennsylvania

Moreno, an elected member of the National Academy of Medicine, studies medical ethics and health policy, the history and sociology of science, and philosophy. He received  his Ph.D. in philosophy from Washington University in St. Louis and was an Andrew W. Mellon post-doctoral fellow. His book The Body Politic: The Battle Over Science in America was a Kirkus Reviews Best Book of the Year and a Scientific American Book Club selection. More recently, he wrote Everybody Wants to Go to Heaven but Nobody Wants to Die: Bioethics and the Transformation of Healthcare in America with former Penn President Amy Gutmann.

Moreno received the 2018 Lifetime Achievement Award of the American Society for Bioethics and Humanities. 

The abstract for his April 4 lecture can be found here.

The Irving and Renee Milchberg Endowed Lectureship was established by Prof. Howard Milchberg and his wife Rena, to remember Howard's parents, who survived the Holocaust and the distortions of truth that accompanied and facilitated it.  Milchberg’s mother and father, who died in 2017 and 2014, respectively, never received formal education, but Milchberg describes them as “remarkably open-minded and tolerant” and as “wide-ranging thinkers and skeptics.” 

Manuel Franco Sevilla Receives Junior Faculty Award

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Category: Department News

Published: Tuesday, February 21 2023 05:07

Manuel Franco Sevilla has received the 2022 Junior Faculty Award from the Board of Visitors of the College of Computer, Mathematics and Natural Sciences in recognition of his “exceptional accomplishments that have raised the profile and prestige of the college”.

Franco Sevilla is a particle physicist doing research at CERN’s Large Hadron Collider’s beauty (LHCb) experiment, which employs “beauty” (or “b”) hadrons produced in high-energy collisions of protons to study the fundamental laws of our Universe.Manuel Franco Sevilla

His research focuses on measurements that test lepton universality, a fundamental assumption within the Standard Model of particle physics that states that the interactions of all charged leptons (electrons, muons, and taus) differ only because of their different masses. His thesis in 2012 saw the first hints of possible lepton universality violation, and since then, several measurements in experiments across the world have found similar hints. He has covered this topic in multiple international forums and in reviews for Nature and Review of Modern Physics.

Additionally, Franco Sevilla works on the Upstream Tracker (UT), a new silicon tracker that is a crucial part of LHCb’s ongoing upgrade to achieve data taking rates five times larger than previously possible. Together with Professor Hassan Jawahery, he co-led the development and production of the readout electronics for the UT, a total of over 600 main boards and 3,000 ancillary ones. This immense effort included contributions from an electronics engineer, three postdocs, four graduate students and the recruitment and training of a group of 12 undergraduate students who were instrumental during the testing and assembly phases of the project.

Last year Franco Sevilla was named deputy project leader of the UT and spent the second half of 2022 at CERN coordinating the assembly and installation of this subdetector into the LHCb experiment, an effort that involved a team of over 25 engineers, technicians, postdocs, and students as well as other CERN resources such as survey, transportation, or radiation protection teams. Some pictures of theses activities are shown below.

Shining a light on LHCb's Upstream Tracker silicon sensors to measure whether their dark current increases—a sign that the sensors are properly connected to the high voltage circuit.

Transporting the last stave of the Upstream Tracker (UT).

The last stave being installed into the UT.

The team that installed the last UT stave on December 10, 2022.

The cutout on the inner staves as it is being laser surveyed to make sure it will not impact the beam pipe that carries LHC's protons.

Half of the UT being transported to the LHCb cavern.

Half of the UT being lowered 100 meters underground into the LHCb cavern.

Half of the UT at the bottom of the LHCb shaft.

The LHCb experimental cavern.

Half of the UT being lifted above the LHCb experiment to install it on the other side of the beam pipe.

One half of the UT being pushed into position.

The staves of half of the UT in position around the beam pipe that carries LHC's protons.

The team that cabled up the UT during CERN's Christmas closure.

After the UT installation, a break on the 25th of December at the Alps. Mont Blanc can be seen on the background.

(Possibly) Breaking the Standard Model, One Lepton-universality-violating Decay at a Time

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Category: Research News

Published: Thursday, February 09 2023 02:53

Physicists in general, and high energy physicists in particular, like to "break" things. It can be useful to prove again that a well established theory is true, especially if you are probing a yet-untested prediction of the venerable theory. But proving that the theory is wrong--or at least not completely true--that is where the fun is. This is why a series of measurements of b hadron decays that seemingly break the Standard Model (SM) of particle physics is garnering so much excitement.

You see, the SM is the most well established theory of them all, the only one with predictions corroborated to the 11th digit (see the anomalous magnetic moment of the electron). It was fully fleshed out in the 70's, and since then it has racked up success after success. Its crowning achievement came in 2012 when the long-predicted Higgs boson was finally confirmed to be alive and well. Despite this resiliency, the SM is not the end of it all. It can't explain why the mass of the Higgs is so low, what the nature of dark matter is, or why there is so much more matter than antimatter in the universe. Finding answers to these questions will thus require breaking, or extending, the SM.

Enter Lepton Flavor Universality (LFU) violation. LFU is a fundamental assumption within the SM involving the three lepton flavors: electron, muon, and tau. All SM interactions other than the Higgs are assumed to be flavor universal, and this has been shown to be true in numerous measurements. Since 2012, however, an intriguing pattern has emerged in decays of b hadrons (particles with a b quark inside) to final states with a c quark, a tau lepton τ, and a neutrino ν. When results involving a tau lepton and a neutrino are compared to decays involving a muon or an electron and a neutrino, they tend to be higher than we'd expect from SM calculations. This is shown in the nearby figure by all the measurements keeping their distance from the theoretical predictions in blue. Measurements that measured the two LFU quantities RD and RD* are shown as Artistic representation of a proton-proton collision resulting in a B meson that subsequently decays to a charmed D0 or D* meson, a tau lepton, as well as a smaller antineutrino. Credit: Greg Stewart, SLAC National Accelerator Laboratory/BaBar and Manuel Franco Sevilla.ellipses while measurements of RD* alone are shown as markers with uncertainties.

And the first of these new results was just submitted to Physical Review Letters  Professor Hassan Jawahery and Dr. Phoebe Hamilton, together with Dr. Greg Ciezarek from CERN, measured for the first time RD and RD* simultaneously at LHCb. The uncertainties are still large, so it is hard to say whether the discrepancy will be proven true. But this result sets the stage for another meaThe results reflect analysis of two years of data by Phoebe Hamilton and Hassan Jawahery and their CERN collaborator, Greg Ciezarek.surement based on the same techniques that uses a data sample more than 6 times larger. This work, carried out by the all-UMD team Professor Manuel Franco Sevilla, Dr. Hamilton, Dr. Christos Hadjivasiliou, Yipeng Sun, and Alex Fernez, is now fairly advanced. So stay tuned, there's potential for SM-breaking ahead!

 --Manuel Franco Sevilla

James J. Griffin, 1930-2022

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Category: Department News

Published: Sunday, February 05 2023 10:37

Professor Emeritus James J. Griffin died on December 13, 2022.

Griffin earned his Ph.D. in theoretical physics at Princeton University in 1956 and then accepted a Fulbright Scholarship to the Institute for Theoretical Physics in Copenhagen. Following a National Science Foundation Fellowship at the University of Birmingham and an appointment as a Visiting Lecturer at the University of Wisconsin, he joined UMD as an assistant professor in 1966. He was promoted to associate professor and full professor in 1968 and 1973, respectively. In the 1968-69 academic year, Griffin served as Associate Chair of the UMD Department of Physics and Astronomy.

Griffin studied nuclear structure and heavy ions, and was perhaps best known for his publication, “The statistical model of intermediate structure,” which appeared in Physical Review Letters.  He received a John Simon Guggenheim Foundation Fellowship to work at the Lawrence Berkeley Laboratory in 1972-73. In 1975, he received an Alexander von Humboldt Foundation Senior Scientist Fellowship and worked at the Justus Liebig University in Giessen and the Hahn Meitner Institute for Nuclear Research in Berlin.   

During his career, Griffin also enjoyed visiting positions at Los Alamos National Laboratory, Oak Ridge National Laboratory, the University of California in Berkeley, and several institutions in France and Germany. He was an invited guest lecturer in Germany, Canada, Poland, China, Israel, Japan, France and Romania. 

A memorial is planned for the spring. If you'd like to be notified when it is scheduled, please contact This email address is being protected from spambots. You need JavaScript enabled to view it..

Shining a light on LHCb's Upstream Tracker silicon sensors to measure whether their dark current increases—a sign that the sensors are properly connected to the high voltage circuit.

Transporting the last stave of the Upstream Tracker (UT).

The last stave being installed into the UT.

The team that installed the last UT stave on December 10, 2022.

The cutout on the inner staves as it is being laser surveyed to make sure it will not impact the beam pipe that carries LHC's protons.

Half of the UT being transported to the LHCb cavern.

Half of the UT being lowered 100 meters underground into the LHCb cavern.

Half of the UT at the bottom of the LHCb shaft.

The LHCb experimental cavern.

Half of the UT being lifted above the LHCb experiment to install it on the other side of the beam pipe.

One half of the UT being pushed into position.

The staves of half of the UT in position around the beam pipe that carries LHC's protons.

The team that cabled up the UT during CERN's Christmas closure.

After the UT installation, a break on the 25th of December at the Alps. Mont Blanc can be seen on the background.