Study of same-sign W boson scattering and anomalous couplings in events with one tau lepton from pp collisions at $\sqrt{s}$ = 13 TeV

TL;DR

This paper measures the cross section of same-sign W boson scattering involving a tau lepton at 13 TeV and searches for signs of new physics through effective field theory operators, using CMS data.

Contribution

It provides the first measurement of same-sign WW scattering with a tau lepton and explores potential beyond Standard Model effects via EFT frameworks.

Findings

Measured cross section is 1.44 times the SM prediction.

Set limits on anomalous couplings using EFT operators.

Analyzed 138 fb$^{-1}$ of CMS data at 13 TeV.

Abstract

A first study is presented of the cross section for the scattering of same-sign W boson pairs via the detection of a $\tau$ lepton. The data from proton-proton collisions at the center-of-mass energy of 13 TeV were collected by the CMS detector at the LHC, and correspond to an integrated luminosity of 138 fb$^{-1}$. Events were selected that contain two jets with large pseudorapidity and large invariant mass, one $\tau$ lepton, one light lepton (e or $\mu$), and significant missing transverse momentum. The measured cross section for electroweak same-sign WW scattering is 1.44 $^{+0.63}_{-0.56}$ times the standard model prediction. In addition, a search is presented for the indirect effects of processes beyond the standard model via the effective field theory framework, in terms of dimension-6 and dimension-8 operators.