SemiCharmTag: a tool for Semileptonic Charm tagging

TL;DR

SemiCharmTag is a new tool designed to improve charm semileptonic decay lepton identification and background rejection in LHCb dimuon Drell-Yan measurements, enhancing signal purity and efficiency.

Contribution

It introduces a novel secondary vertex tagging method and background rejection strategy specifically for charm semileptonic decay lepton selection in high-energy proton-proton collisions.

Findings

Achieved a fourfold signal-to-background improvement at 81% efficiency.

Constructed unbiased charm decay muon samples with 21.4% efficiency.

Validated the method using full simulations at 13.6 TeV.

Abstract

A method for selecting and/or rejecting leptons from charm semileptonic decays based on the tagging of the secondary vertex using a hadron track is introduced. The method is developed for dimuon Drell-Yan measurements in LHCb using full simulations in proton-proton collisions at $\sqrt{s}=13.6$ TeV. We focus on the invariant mass range between 2.9 and 5 GeV/$c^2$ with single muon transverse momentum larger than 1 GeV/$c$. A novel strategy is detailed for background rejection, achieving an improvement of the signal over background of a factor $\sim 4$ at an efficiency of 81% with minimal bias on the Drell-Yan signal properties. Moreover, a second approach is presented for the construction of unbiased background-pure samples of single muons from charm decays, achieving a charm efficiency of 21.4% at a Drell-Yan efficiency of 1.1%.