Performance of reconstruction and identification of $\tau$ leptons decaying to hadrons and $\nu_\tau$ in pp collisions at $\sqrt{s}=$ 13 TeV

TL;DR

This paper presents an improved algorithm by the CMS Collaboration for reconstructing and identifying tau leptons decaying to hadrons and neutrinos in 13 TeV proton-proton collisions, demonstrating high efficiency and low misidentification rates.

Contribution

The paper introduces significant enhancements to tau lepton reconstruction and identification algorithms, including better pi0 reconstruction and boosted tau detection, validated with 13 TeV collision data.

Findings

High efficiency for genuine tau identification

Low misidentification rates for jets, electrons, muons

Performance closely matches Monte Carlo simulations

Abstract

The algorithm developed by the CMS Collaboration to reconstruct and identify $\tau$ leptons produced in proton-proton collisions at $\sqrt{s}=$ 7 and 8 TeV, via their decays to hadrons and a neutrino, has been significantly improved. The changes include a revised reconstruction of $\pi^0$ candidates, and improvements in multivariate discriminants to separate $\tau$ leptons from jets and electrons. The algorithm is extended to reconstruct $\tau$ leptons in highly Lorentz-boosted pair production, and in the high-level trigger. The performance of the algorithm is studied using proton-proton collisions recorded during 2016 at $\sqrt{s}=$ 13 TeV, corresponding to an integrated luminosity of 35.9 fb$^{-1}$. The performance is evaluated in terms of the efficiency for a genuine $\tau$ lepton to pass the identification criteria and of the probabilities for jets, electrons, and muons to be misidentified as $\tau$ leptons. The results are found to be very close to those expected from Monte Carlo simulation.