2023/06/18 by Barik, Anjan Kumar, Dey, Atri, Samui, Tousik · 1 citation
#FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High Energy Physics - Phenomenology (hep-ph)
paper · doi:10.48550/arxiv.2306.10540
The search for lepton flavor violation (LFV) is a powerful probe to look for new physics beyond the Standard Model. We explored the possibility of searches for LFV Z boson couplings to electron and muon pairs at the upcoming electron-proton colliders, namely the Large Hadron Electron Collider (LHeC) and the Future Circular lepton-hadron Collider (FCC-eh). We employed the study via a single muon plus an associated jet channel to search for the LFV signal. We used a multivariate technique to obtain an improved signal-background analysis. By using the condition on nonobservation of any significant deviation of the signal over the expected background, we provide an upper limit on the LFV Z boson coupling and corresponding branching ratio (BR). We find that an upper limit of up to 1.13× 10-7 and 4.64 × 10-8 can be set on BR(Z→ e μ) at 95% confidence level (C.L.) with one year run of LHeC and FCC-eh, respectively, if the LFV coupling is governed by vector or axial-vector coupling. For tensor or axial-tensor coupling, these limits can be improved up to 2.34× 10-8 and 5.02× 10-9 for LHeC and FCC-eh machines, respectively, at 95% C.L. The projected numbers improve significantly over the existing limit of 2.62× 10-7 set by ATLAS.