Search for light Higgs bosons from supersymmetric cascade decays in pp collisions at $\sqrt{s}$ = 13 TeV

TL;DR

This paper reports a search for light Higgs bosons produced in supersymmetric cascade decays at the LHC, using CMS data, but finds no evidence and sets exclusion limits on certain mass ranges and production cross sections.

Contribution

It introduces a novel search strategy for light Higgs bosons in supersymmetric cascade decays using jet substructure techniques at 13 TeV.

Findings

No excess observed beyond SM background.

Excluded Higgs boson masses from 40 to 120 GeV for certain squark/gluino masses.

Set upper limits on production cross sections in the studied model.

Abstract

A search is reported for pairs of light Higgs bosons (H$_1$) produced in supersymmetric cascade decays in final states with small missing transverse momentum. A data set of LHC pp collisions collected with the CMS detector at $\sqrt{s}$ = 13 TeV and corresponding to an integrated luminosity of 138 fb$^{-1}$ is used. The search targets events where both H$_1$ bosons decay into $\mathrm{b\bar{b}}$ pairs that are reconstructed as large-radius jets using substructure techniques. No evidence is found for an excess of events beyond the background expectations of the standard model (SM). Results from the search are interpreted in the next-to-minimal supersymmetric extension of the SM, where a "singlino" of small mass leads to squark and gluino cascade decays that can predominantly end in a highly Lorentz-boosted singlet-like H$_1$ and a singlino-like neutralino of small transverse momentum. Upper limits are set on the product of the squark or gluino pair production cross section and the square of the $\mathrm{b\bar{b}}$ branching fraction of the H$_1$ in a benchmark model containing almost mass-degenerate gluinos and light-flavour squarks. Under the assumption of an SM-like H$_1$ $\to$ $\mathrm{b\bar{b}}$ branching fraction, H$_1$ bosons with masses in the range 40-120 GeV arising from the decays of squarks or gluinos with a mass of 1200 to 2500 GeV are excluded at 95% confidence level.