2023/01/23 by Mathew Thomas Arun, Kuldeep Deka, Arun, Mathew Thomas +3 · 1 citation
Computer Science · Physics and Astronomy · #Computational Physics and Python Applications #Particle physics theoretical and experimental studies #Cosmology and Gravitation Theories
paper · pdf · doi:10.48550/arxiv.2301.09273
Precision observables are well known for constraining most of the Beyond Standard Model (BSM) scenarios tightly. We present here a simple and comprehensive fitting framework for various BSM scenarios to these observables. We start with the fit of S, T and V parameter and their correlations using the Electroweak Precision Observables (EWPO) including the recent mW measurement from CDF-II. Utilizing these observables, we also fit various New Physics (NP) scenarios consisting of different subsets of dimension-6 Standard Model Effective Field Theory (SMEFT) operators in the Warsaw basis out of a total of 10 appearing at tree level in EWPO. To further constrain these scenarios, we augment these observables with ΔCKM measurement using 1-loop matching of the Low Energy Effective Field Theory (LEFT) to SMEFT operators at the Z-pole. We show that the inclusion of ΔCKM constraint indeed results in stronger bounds on the SMEFT Wilson Coefficients. We also constrain the UV parameters of BSM extensions like Vectorlike leptons (VLL) and find out that such a minimal extension is in tension with the forward-backward asymmetry in b-sector (AbFB) and the recent measurement of MW. In order to lift the two blind directions, which one encounters while fitting all the 10 SMEFT WCs at tree-level, we also include the LEP-II observables pertaining to the WW production and present the results for the fits with and without ΔCKM constraint.