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

October 6, 2026 2:00 PM
PAIS 3205

Host:

Sally Seidel

Presenter:

Saheed Oyeniran (UNM)

The Standard Model describes known particle interactions with remarkable precision, but it does not explain the observed matter-antimatter asymmetry of the Universe. One way to search for physics beyond the SM is to measure flavor-changing processes whose SM amplitudes are suppressed or highly constrained. My dissertation follows this precision-flavor strategy. The central project is a time-dependent angular analysis of B_s⁰ → J/ψ φ with the ATLAS detector, aimed at measuring the CP-violation phase φ_s, the decay-width difference ΔΓ_s, the average decay width Γ_s, and related B_s⁰ to anti-B_s⁰ mixing parameters. Because the SM expectation for φ_s is small, a statistically significant deviation could indicate new virtual contributions to B_s⁰ mixing. The dissertation then extends the heavy-flavor program toward future facilities through studies of B_c⁺ production at FCC-ee and the possible extraction of CKM element V_cb from leptonic/semi-leptonic decay channels with potential sensitivity to new physics. The remaining projects address the detector foundation required for these measurements: radiation-induced leakage current in the ATLAS Pixel Detector B-Layer and Transient Current Technique (TCT) characterization of 3D trench silicon sensors for future tracking systems. Together, these projects connect current ATLAS flavor measurements, future collider opportunities, radiation-damage monitoring, and next-generation silicon detector R&D, all in the search for physics beyond the Standard Model.