Sensitivity of $W$-boson measurements to low-mass right-handed neutrinos

TL;DR

This paper investigates how measurements of W-boson properties at colliders can constrain low-mass right-handed neutrinos, revealing potential inconsistencies and proposing improved measurement strategies at the LHC.

Contribution

It introduces a novel analysis using effective field theory to connect W-boson measurements with right-handed neutrino interactions and highlights the potential for improved sensitivity at the LHC.

Findings

Inconsistencies between Tevatron and LHC measurements suggest new physics constraints.

LHC can enhance sensitivity by analyzing the helicity angle at high transverse momentum W bosons.

Current measurements place bounds on right-handed neutrino interactions with electroweak bosons.

Abstract

A low-mass right-handed neutrino could interact with electroweak bosons via mixing, a mediator particle, or loop corrections. Using an effective field theory, we determine constraints on these interactions from $W$-boson measurements at hadron colliders. Due to the difference in the initial states at the Tevatron and the LHC, $W$-boson decays to a right-handed neutrino would artificially increase the mass measured at the Tevatron while only affecting the difference between $W^+$ and $W^-$ mass measurements at the LHC. Measurements from CDF and the LHC are used to infer the corresponding parameter values, which are found to be inconsistent between the two. The LHC experiments can improve sensitivity to these interactions by measuring the cosine of the helicity angle using $W$ bosons produced with transverse momentum above $\approx 50$ GeV.