Search for new phenomena with large jet multiplicities and missing transverse momentum using large-radius jets and flavour-tagging at ATLAS in 13 TeV $pp$ collisions

TL;DR

This paper reports a search for new particles producing many jets and missing energy in 13 TeV proton-proton collisions, using ATLAS data, but finds no evidence for physics beyond the Standard Model.

Contribution

It introduces a novel analysis strategy combining large-radius jets and flavour-tagging to enhance sensitivity to supersymmetric models.

Findings

No significant excess observed over Standard Model predictions.

Limits set on gluino masses in various supersymmetric models.

Analysis demonstrates the effectiveness of jet multiplicity and flavour-tagging techniques.

Abstract

A search is presented for particles that decay producing a large jet multiplicity and invisible particles. The event selection applies a veto on the presence of isolated electrons or muons and additional requirements on the number of b-tagged jets and the scalar sum of masses of large-radius jets. Having explored the full ATLAS 2015-2016 dataset of LHC proton-proton collisions at $\sqrt{s}=13~\mathrm{TeV}$, which corresponds to 36.1 fb$^{-1}$ of integrated luminosity, no evidence is found for physics beyond the Standard Model. The results are interpreted in the context of simplified models inspired by R-parity-conserving and R-parity-violating supersymmetry, where gluinos are pair-produced. More generic models within the phenomenological minimal supersymmetric Standard Model are also considered.