Anomalies in the production of multiple leptons at the LHC

TL;DR

This paper reports significant discrepancies between observed multi-lepton events at the LHC and Standard Model predictions, suggesting potential new physics or mismodeling issues in current simulations.

Contribution

It presents evidence of anomalies in multi-lepton production at the LHC that challenge existing SM predictions, highlighting areas for further investigation.

Findings

Significant discrepancies in multi-lepton final states

Anomalies persist across different phase-space regions

Current SM modeling tools cannot fully explain the discrepancies

Abstract

Based on a number of features from proton-proton collisions taken during Run 1 data taking period at the LHC, a boson with a mass around the Electro-Weak scale was postulated such that a significant fraction of its decays would comprise the Standard Model (SM) Higgs boson and an additional scalar, $S$. One of the phenomenological implications of a simplified model, where $S$ is treated a SM Higgs boson, is the anomalous production of high transverse momentum leptons. A combined study of Run 1 and Run 2 data is indicative of very significant discrepancies between the data and SM Monte Carlos in a variety of final states involving multiple leptons with and without $b$-quarks. These discrepancies appear in corners of the phase-space where different SM processes dominate, indicating that the potential mismodeling of a particular SM process is unlikely to explain them. Systematic uncertainties from the prediction of SM processes evaluated with currently available tools seem unable to explain away these discrepancies. The internal consistency of these anomalies and their interpretation in the framework of the original hypothesis is quantified.