ausblenden:
Schlagwörter:
High Energy Physics - Experiment, hep-ex
MPINP:
LHCb - Abteilung Hinton
Zusammenfassung:
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/$c$.