IN-PERSON
Zhangqier Wang
Measurements of B(s)-> μ+μ- decays properties in proton-proton collisions at 13 TeV
Abstract:
Rare B meson decays proceeding via flavour-changing neutral currents allow precision tests of the Standard Model and provide a sensitive probe for potential beyond-the-Standard-Model contributions. I will present new measurements of the Bs → μ+μ− branching fraction and effective lifetime, as well as results of a search for the B0 → μ+μ− decay. The analysis is based on pp collision data collected by the CMS experiment at sqrt(s)=13 TeV during the LHC Run 2, corresponding to an integrated luminosity of 140 fb−1. The measured branching fraction of the Bs-> μ+μ- decays and the effective Bs lifetime are the most precise to date. No evidence for the B0-> μμ decay has been found. All results are found to be consistent with the standard model predictions.
time: 4:00 p.m.
place: Kolker Room (26-414)
IN-PERSON/VIRTUAL
No Speaker Scheduled
Abstract:
time: 4:00 p.m.
place: Kolker Room (26-414)
IN-PERSON/VIRTUAL
No Speaker Scheduled
Abstract:
time: 4:00 p.m.
place: Kolker Room (26-414)
IN-PERSON
Matthew Schwartz
Measuring αs from jet mass
Abstract:
One of the key parameters in the Standard Model is the strong coupling constant αs. It has been extracted from data in numerous ways, from lattice QCD to top quark cross sections, with remarkable consistency. There is, however, some small tension between low-energy extractions using lattice QCD or decay rates and high-energy extractions using colliders. On the high-energy side, one powerful observable at colliders for measuring αs is the mass of jets. Progress has been made on precision predictions of the jet mass and both e+e- colliders and hadron colliders. At e+e- colliders, jet mass is often measured through the heavy jet mass, which has some unusual properties contrasting it with other event shapes like thrust. In particular, it manifests a left Sudakov shoulder which must be understood before αs can be extracted. At hadron colliders, jet mass suffers from contamination due to underlying events and pileups. A remedy is to use the soft-drop jet mass. This talk will overview recent progress on the Sudakov shoulder effect and computations of the soft drop jet mass, and discuss prospects for improving the high-energy measurements of αs.
time: 4:00 p.m.
place: Kolker Room (26-414)
IN-PERSON/VIRTUAL
No Speaker Scheduled
Abstract:
time: 4:00 p.m.
place: Kolker Room (26 -414)
IN-PERSON
Jaco de Swart
How Dark Matter Came to Matter
Abstract:
In 1974, two independent research groups in the U.S. and Estonia concluded the existence of missing mass: a yet-unseen type of matter distributed throughout the universe. Their conclusion formed the foundation of today's dark matter research. This talk is about how this conclusion was established: the history of the dark matter problem. I address how in the 1960s the radial constancy of galaxies' rotational velocity was observed. As early as the 1930s it was known that the masses of galaxies did not add up to make sense of the dynamics of galaxy clusters. I show that, although both observations are in hindsight considered evidence for the existence of dark matter, only in 1974 were these results put together as a single consistent problem. It was then that dark matter came to matter.
time: 4:00 p.m.
place: Kolker Room (26-414)
IN-PERSON
Austin Schneider
From PeV to Mev: Neutrinos across the energy scale
Abstract:
Neutrinos have a history of showing us the unexpected; and anomalous results from the Liquid Scintillator Neutrino Detector, MiniBooNE, the Bhaskan Experiment on Sterile Transitions, and others show us that this story is still evolving to this day. In this talk I will discuss how the outlook of sterile neutrino oscillations and beyond standard model neutrino physics has evolved in recent years, using examples from my own work. We will cover results across a wide range of energy scales, from multi-PeV observations with the IceCube South Pole Neutrino Observatory to the upcoming Coherent CAPTAIN Mills - 200 experiments operating at the MeV scale, which are united by the physics that can be probed.
time: 4:00 p.m.
place: Kolker Room (26-414)
IN-PERSON
Paul Romatschke
Transport at Strong Coupling -- a Field Theory Approach
Abstract:
Transport properties are hard to calculate from the first principles for any value of the coupling. At strong coupling, it's generally considered impossible except for field theories with known gravity duals. In this talk, I will review large N approaches to simple scalar and fermion field theories and show that they allow for the determination of exact transport coefficients at strong coupling, directly from the field theory. As an example, I calculate the (large N exact) infinite coupling value of eta/s in the 3d O(N) model.
time: 4:00 p.m.
place: Kolker Room (26-414)
IN-PERSON
Gordan Krnjaic
Dial M for Muons
Abstract:
The longstanding muon g-2 anomaly is perhaps the largest discrepancy in fundamental physics and could become the first laboratory discovery of physics beyond the Standard Model of particles and interactions. In this talk, I will review what it means to measure a magnetic dipole moment, categorize the different theoretical possibilities for new particles that resolve the anomaly, and present a road map for how to discover the new particles responsible (even in a worst-case "nightmare" scenario). A decisive probe of the underlying new physics will involve a combination of rare particle decay searches, new muon beam fixed-target experiments, and possibly even a future muon collider.
time: 4:00 p.m.
place: Kolker Room (26-414)
IN-PERSON
Roxanne Springer
Probing fundamental symmetries using low-energy few-nucleon interactions
Abstract:
QCD is both a feature and a bug when it comes to understanding symmetries of the standard model or looking beyond the standard model. Few-nucleon interactions at low energies provide a relatively well controlled environment for probing the interplay between QCD and tiny symmetry-violating effects. Using effective field theories and approximate symmetries, such as the simplification that occurs in the large-number-of -colors limit of QCD, provide a systematic way to encode a suite of observables in
just a few operators and their associated low-energy-coefficients. It is particularly useful
to study the hierarchy of NN interactions that determine the leading edge of precision measurements in order to guide future experiments and further theoretical efforts.
time: 4:00 p.m.
place: Kolker Room (26-414)
IN-PERSON
Caroline Robin
Quantum Information for the Nuclear Many-Body Problem
Abstract:
In the past years increasing effort has been devoted to re-examining quantum many-body systems from a quantum information point of view. In particular, there has been renewed interest in understanding the phenomenon of entanglement due to its essential role in quantum computing and potential guidance in formulating the many-body problem. While extensive investigations of this topic have been performed in condensed matter and quantum chemistry, the exploration of entanglement in nuclear physics has only recently begun.
In this talk, we discuss the characterization of entanglement in nuclear systems and investigate entanglement properties of light nuclei obtained in the context of nuclear structure calculations with effective model spaces. We study how entanglement rearranges into more localized structures when the Hamiltonian is transformed into an effective one and how these patterns can indicate the emergence of physical phenomena [1].
In the second part of the talk, we investigate how entanglement localization can be exploited to design efficient quantum computations of nuclear systems. We develop a “Hamiltonian-Learning Variational Quantum Eigensolver” (HL-VQE) procedure to simultaneously determine the Hamiltonian and ground-state wave function ineffective model spaces [2]. As a test case, we apply this procedure to the Lipkin-Meshkov-Glick model [3] with a real quantum computer.
time: 4:00 p.m.
place: Kolker Room (26-414)
IN-PERSON/VIRTUAL
Abby Vieregg
Using Radio Detectors to Discover the Highest Energy Neutrinos
Abstract:
The detection of high energy astrophysical neutrinos is an important step toward
understanding the most energetic cosmic accelerators. IceCube, a large optical
detector at the South Pole, has observed the first astrophysical neutrinos and
identified at least one potential source. However, the best sensitivity at the
highest energies comes from detectors that look for coherent radio Cherenkov
emission from neutrino interactions. I will give an overview of the state of
current experimental efforts, including recent results, and then discuss a suite
of new experiments designed to discover neutrinos at the highest energies and push
the energy threshold for radio detection down to overlap with the energy range
probed by IceCube, thus covering the full astrophysical energy range out to the
highest energies, and opening up new phase space for discovery. These include
ground-based experiments such as RNO-G and IceCube-Gen2, as well as the
balloon-borne experiment PUEO.
time: 4:00 p.m.
place: Kolker Room (26-414)
IN-PERSON
Nick Hutzler
Fundamental science with polyatomic molecules
Abstract:
The extra degrees of freedom of polyatomic molecules allow the combination of multiple features which are incongruous in simpler systems, and enable design and tuning of molecules for desired applications. We will discuss experimental progress toward using polyatomic molecules for CP-violation searches, which benefit from the ability to combine photon cycling with high polarizability through parity doublets and the ability to control electromagnetic interactions, as well as the ability to include a wide range of nuclei, including radioactive species. We will also discuss theoretical progress toward developing new motifs for engineering molecules with photon cycling centers with distinctly different properties than those previously developed, and which offer new opportunities and directions for fundamental and quantum science.
time: 4:00 p.m.
place: Kolker Room (26-414)
