• Nuclear, Particle, Astroparticle and Cosmology (NUPAC) Seminars

January 20, 2026 2:00 PM
PAIS 3205

Host:

Sally Seidel

Presenter:

Andrew Gentry (UNM)

Measurements of rare decays of heavy-flavor hadrons, such as the neutral B meson, have the potential to reveal subtle variations from Standard Model predictions, providing indirect signals of physics Beyond the Standard Model. The ATLAS experiment at the Large Hadron Collider is one of just a few experiments where large numbers of B mesons are produced and detected. A new measurement is underway of the branching ratio of the rare decay of a neutral B meson to K-short plus two muons using ATLAS data. Prior studies of that decay and several others also involving the transition of a b-quark to an s-quark and two leptons have revealed tension with Standard Model predictions. This tension is primarily driven by measurements made by LHCb. Therefore, it is critical for other experiments to confirm or contradict these results. The recent progress on this project will be covered, including work on background simulations, machine learning techniques for background discrimination, and fitting of the B-candidate invariant mass distribution.

Several next-generation experiments, including proposed high-energy colliders, will need innovative detector technology to achieve their goals. Silicon detectors have for decades been a primary workhorse for collider physics experiments, and developments in this area continue. Silicon detectors typically have an unwanted insensitive area at the periphery due to processing limitations. Active Edge silicon sensors have already been shown to be a viable way to reduce the insensitive area, but fabrication of Active Edge technology has thus far proven difficult. A feasibility study of a new process that could greatly simplify the fabrication of Active Edge sensors will be discussed.

Microwave annealing has been shown previously to be a successful method for reducing defects in some semiconductor devices. However, until now, no studies have been performed of its potential for removing defects in irradiated devices. A study is underway of the effect of microwave annealing on both irradiated and unirradiated MOS devices. Results demonstrating both improvement of device performance prior irradiation, and partial reversal of radiation damage, will be shown.