Search for New Physics in the Rare Decays B0(s)→µ+µ− and Development of High-Precision Timing Detectors

Author

• Josef Daniel Sorenson, University of New MexicoFollow

Publication Date

Spring 5-16-2026

Abstract

The measurement of the B0→µ+µ− and B0s→µ+µ− branching ratios may imply

contributions from possible flavor changing new physics. The measurement of these

branching ratios using the ATLAS complete Run 2 (2015-2018) datasets is presented.

A boosted decision tree is trained to discriminate between the dominant combinatorial

background and the rare signal events. The reference channel yield is extracted using

improved procedures and systematic evaluation. Future hadron colliders, that could

extend the study, including the High-Luminosity LHC (HL-LHC), will have higher

instantaneous luminosity resulting in higher pileup background and radiation damage.

To ensure high quality data taking in the HL-LHC and future colliders, precision

timing resolution at the track and hit level has been explored. Gamma and proton

irradiation studies on Low Gain Avalanche Detectors (LGADs) have been undertaken

to assess their performance in the HL-LHC environment. Prototype low jitter readout

electronics fabricated in the 28 nm CMOS node have been characterized and their

performance assessed for detectors at future colliders.

Degree Name

Physics

Level of Degree

Doctoral

Department Name

Physics & Astronomy

First Committee Member (Chair)

Sally Seidel

Second Committee Member

Alessandro Cerri

Third Committee Member

Maurice Garcia-Sciveres

Fourth Committee Member

Dinesh Loomba

Fifth Committee Member

Francis-Yan Cyr-Racine

Language

English

Keywords

B Mesons, Silicon Detectors, Radiation Damage, Readout Electronics

Document Type

Dissertation

Recommended Citation

Sorenson, Josef Daniel. "Search for New Physics in the Rare Decays B0(s)→µ+µ− and Development of High-Precision Timing Detectors." (2026). https://digitalrepository.unm.edu/phyc_etds/365