Search for beautiful tetraquarks in the $\Upsilon(1S)\mu\mu$ invariant-mass spectrum

TL;DR

This study searches for exotic tetraquark states composed of four bottom quarks in the $
$ spectrum using LHCb data, but finds no evidence and sets upper limits on production rates.

Contribution

First search for $X_{b\overline{b}b\overline{b}}$ tetraquarks in the $
\mu\mu$ spectrum with comprehensive LHCb data, establishing upper limits on their production.

Findings

No significant excess observed.

Upper limits set on production cross-section times branching fraction.

Constraints provided within specific kinematic fiducial volume.

Abstract

The $\Upsilon(1S)\mu^+\mu^-$ invariant-mass distribution is investigated for a possible exotic meson state composed of two $b$ quarks and two $\overline{b}$ quarks, $X_{b\overline{b}b\overline{b}}$. The analysis is based on a data sample of $pp$ collisions recorded with the LHCb detector at centre-of-mass energies $\sqrt{s} =$ 7, 8 and 13 TeV, corresponding to an integrated luminosity of 6.3 fb$^{-1}$. No significant excess is found, and upper limits are set on the product of the production cross-section and the branching fraction as functions of the mass of the $X_{b\overline{b}b\overline{b}}$ state. The limits are set in the fiducial volume where all muons have pseudorapidity in the range $[2.0,5.0]$, and the $X_{b\overline{b}b\overline{b}}$ state has rapidity in the range $[2.0,4.5]$ and transverse momentum less than 15 GeV/$c$.