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

February 24, 2026 2:00 PM
PAIS 3205

Host:

Sally Seidel

Presenter:

Hijas Farook (UNM)

The decays of neutral B mesons to oppositely charged muon pairs are a flavor changing neutral current process which is highly suppressed in the Standard Model. The experimental search for these decays is a compelling method to find New Physics indirectly. I will discuss the analysis technique that is used to statistically improve the uncertainties, and the philosophy and implementation of the search, concentrating on the branching ratio measurement using the Run 2 data collected by the ATLAS experiment at the Large Hadron Collider.

Secondly, the High Luminosity upgrade of the LHC will increase the number of interactions per bunch crossing, and this will improve the statistics of branching ratio measurements for channels such decays of neutral B mesons to oppositely charged muon pairs. But the increased number of particles associated with this additional luminosity adds to the radiation damage of the detectors, and this damage has important implications for data-taking operations, charged-particle track reconstruction, detector simulations, and physics analysis. Simulations and measurements of the leakage current in the ATLAS Pixel detector as a function of location in the detector, applied fluence, and time, using data collected in Run 2 (2015-2018), and partial Run 3 (2022-2026) of the Large Hadron Collider are presented.

Increased luminosity will also increase the complexity of reconstructing the events. I describe a new detector technology, AC-coupled Low Gain Avalanche Detectors, which improves the vertex identification capability to disambiguate nearly simultaneous interactions in the bunch crossing. Additionally, I present results from radiation hardness studies on these sensors.