Search for beautiful tetraquarks in the ϒ(1S)μ + μ − invariant-mass spectrum

The Υ(1S)µ +µ − invariant-mass distribution is investigated for a possible exotic meson state composed of two b quarks and two b quarks, Xbbbb . The analysis is based on a data sample of pp collisions recorded with the LHCb detector at centre-of-mass energies √ 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 Xbbbb state. The limits are set in the fiducial volume where all muons have pseudorapidity in the range [2.0, 5.0], and the Xbbbb state has rapidity in the range [2.0, 4.5] and transverse momentum less than 15 GeV/c. Keywords: B physics, Exotics, Hadron-Hadron scattering (experiments), Heavy quark production