Prospect for measuring the CP phase in the hττ coupling at the LHC
Journal
Physical Review D - Particles, Fields, Gravitation and Cosmology
Journal Volume
91
Journal Issue
7
Date Issued
2015
Author(s)
Askew A
Jaiswal P
Okui T
Prosper H.B
Sato N.
Abstract
The search for a new source of CP violation is one of the most important endeavors in particle physics. A particularly interesting way to perform this search is to probe the CP phase in the hττ coupling, as the phase is currently completely unconstrained by all existing data. Recently, a novel variable Θ was proposed for measuring the CP phase in the hττ coupling through the τ±→π±π0ν decay mode. We examine two crucial questions that the real LHC detectors must face, namely, the issue of neutrino reconstruction and the effects of finite detector resolution. For the former, we find strong evidence that the collinear approximation is the best for the Θ variable. For the latter, we find that the angular resolution is actually not an issue even though the reconstruction of Θ requires resolving the highly collimated π±'s and π0's from the τ decays. Instead, we find that it is the missing transverse energy resolution that significantly limits the LHC reach for measuring the CP phase via Θ. With the current missing energy resolution, we find that with ∼1000fb-1 the CP phase hypotheses Δ=0° (the standard model value) and Δ=90° can be distinguished, at most, at the 95% confidence level. © 2015 American Physical Society.
Type
journal article