Addendum to: Combined Constraints on First Generation Leptoquarks

TL;DR

This paper analyzes how recent CMS data on lepton flavor universality violation impacts constraints on first-generation leptoquarks, identifying which representations are favored or excluded based on interference effects and experimental bounds.

Contribution

It provides updated constraints on first-generation leptoquark representations considering recent CMS results, highlighting which models are compatible or disfavored.

Findings

Certain leptoquark representations are favored by CMS excess.

Some representations require large couplings excluded by other data.

Others do not improve the fit over the Standard Model.

Abstract

In this addendum to arXiv:2101.07811 we discuss the implications of the recent CMS analysis of lepton flavour universality violation in non-resonant di-lepton pairs for first generation leptoquarks. As CMS finds more electron events than expected from background, this analysis prefers the LQ representations $\tilde{S}_1, S_2, S_3, \tilde{V}_1, V_2\,(\kappa_2^{RL}\ne 0)$ and $V_3$ which lead to constructive interference with the SM. In principle the excess could also be (partially) explained by the representations $\tilde{S}_2, V_1\,(\kappa_1^R\ne 0), V_2\,(\kappa_2^{LR}\ne 0), \tilde{V}_2$ which are interfering destructively, as this would still lead to the right effect in bins with high invariant mass where the new physics contribution dominates. However, in these cases large couplings would be required which are excluded by other observables. The representations $S_1, V_1\, (\kappa_1^{L} \ne 0)$ cannot improve the fit to the CMS data compared to the SM.