Events During the Week of March 1st through March 8th, 2026
Sunday, March 1st, 2026
- Graduate Program Event
- Ice Skating Social
- Time: 1:30 pm - 3:00 pm
- Place: Bakke Recreation and Wellbeing Center: Sub-Zero Ice Rink (1976 Observatory Drive | Madison, WI 53706)
- Abstract: The Physics Department will be hosting an ice skating social on Sunday, March 1, 1:30pm-3:00pm at the Sub-Zero Ice Rink in Bakke Recreation & Wellbeing Center.
- Host: Alice Kwok
Monday, March 2nd, 2026
- Theory Seminar (High Energy/Cosmology)
- BSM Light Mediator Opportunities from On-Going SM Experiments
- Time: 1:00 pm - 2:30 pm
- Place: Chamberlin 5280
- Speaker: Isaac R. Wang, Fermilab
- Abstract: Light mediators are a type of well-motivated particles. Their masses and couplings can vary in different theories. In this talk, I investigate several new experiments mainly motivated by SM that are sensitive to BSM light mediators, with the example of dark photon and neutrino self-interaction mediator. We found that the MUonE, Hyper-K, IceCube, and GRAND experiments are sensitive to these mediators in a wide range of parameter space.
- Host: Joshua Foster
Tuesday, March 3rd, 2026
- No events scheduled
Wednesday, March 4th, 2026
- Thesis Defense
- Hunting heavy di-Higgs resonances in bbtautau final states and commissioning of GPUs for the CMS High-Level Trigger.
- Time: 1:00 pm - 3:00 pm
- Place: Chamberlin 5280
- Speaker: Ganesh Parida
- Abstract: This thesis presents a search for heavy resonances decaying to pairs of Higgs bosons and the commissioning of GPU-based reconstruction for the CMS high-level trigger system.
The physics search targets massive, narrow-width resonances in the 1 to 4.5 TeV mass range that decay to Higgs boson pairs in the b bbar tau+ tau- final state, using proton-proton collision data at sqrt(s) = 13 TeV recorded by the CMS experiment during 2016 to 2018, corresponding to an integrated luminosity of 138 fb^-1. Such resonances are predicted by beyond-the-Standard-Model theories, which aim to address shortcomings in our current understanding of fundamental particles and their interactions.
The analysis targets final states where one Higgs boson decays into a pair of bottom quarks and the other into a pair of tau leptons: X -> HH -> b bbar tau+ tau-. It uses a single large-radius jet to reconstruct the H -> b bbar decay, while the H -> tau+ tau- decay products can either be contained within a single large-radius jet or appear as two isolated tau leptons. The reconstruction and identification of physics objects used in the analysis are enhanced using advanced machine learning techniques, including a graph convolutional neural network for merged b bbar jets and a convolutional neural network for tau+ tau- identification.
The observed data are consistent with Standard Model background expectations. Upper limits at 95% confidence level are set on the production cross section for resonant HH production for masses between 1 and 4.5 TeV. This analysis sets the most sensitive limits to date on X -> HH -> b bbar tau+ tau- decays in the mass range of 1.4 to 4.5 TeV.
The second component of the thesis describes the commissioning and validation of GPU-based reconstruction at the CMS high-level trigger for Run 3 data-taking. To address increasing computational demands arising from higher instantaneous luminosity and increasing event complexity, parallelizable reconstruction algorithms for the hadron calorimeter, electromagnetic calorimeter, and pixel tracker were offloaded to GPUs. Dedicated physics validation was required to ensure that the GPU-offloaded algorithms produce physics results consistent with CPU-based reconstruction within acceptable tolerances. The final trigger configuration seamlessly utilizes GPU hardware when available while maintaining backward compatibility with CPU-only configuration, establishing a foundation for meeting the computational challenges of the high-luminosity LHC era. - Host: Tulika Bose
Thursday, March 5th, 2026
- R. G. Herb Condensed Matter Seminar
- Dynamical breaking of inversion symmetry, strong second harmonic generation, and ferroelectricity with nonlinear phonons
- Time: 10:00 am - 11:00 am
- Place: 5310 Chamberlin Hall
- Speaker: Egor Kiselev , MPIPKS
- Abstract: I will show how crystalline inversion symmetry can be dynamically broken by optical phonons with generic, hardening Kerr-like non-linearities. The symmetry-broken state is reached through a dynamical phase transition that can be accessed by driving close to half the phonon resonance. After going through an instability, the system settles to a steady state with inversion-symmetry breaking phonon trajectories and strong second harmonic generation. The time averaged positions of the atoms are displaced relative to equilibrium, resulting in a rectification of the driving signal. This leads to a dynamical dipolar, ferroelectric response that shows features like hysteresis and memory effects, known from equilibrium ferroelectrics.
- Host: Elio König
- Astronomy Colloquium
- TBD
- Time: 3:30 pm - 4:30 pm
- Place: 4421 Sterling Hall
- Speaker: Director Julianne Dalcanton, Flatiron Institute/CCA
- Abstract: TBD
- Host: Michael Maseda
Friday, March 6th, 2026
- Physics Department Colloquium
- Title to be announced
- Time: 3:30 pm - 4:30 pm
- Place: Chamberlin 2241
- Speaker: David B. Kaplan, University of Washington
- Host: Daniel Chung