engleski

Observation of B-s(0) mesons and measurement of the B-s(0)/B+ yield ratio in PbPb collisions at root S-NN=5.02 TeV

The B-s(0) and B+ production yields are measured in PbPb collisions at a center-of-mass energy per nucleon pair of 5.02 TeV. The data sample, collected with the CMS detector at the LHC, corresponds to an integrated luminosity of 1.7 nb(-1). The mesons are reconstructed in the exclusive decay channels B-s(0) -> J/psi (mu(+)mu(-))phi(K+K-) and B+ -> J/psi(mu(+)mu(-))K+ in the transverse momentum range 7-50 GeV/c and absolute rapidity 0-2.4. The B-s(0) meson is observed with a statistical significance in excess of five standard deviations for the first time in nucleus-nucleus collisions. The measurements are performed as functions of the transverse momentum of the B mesons and of the PbPb collision centrality. The ratio of production yields of B-s(0) and B+ is measured and compared to theoretical models that include quark recombination effects.

High energy physics ; Experimental particle physics ; LHC ; CMS ; p p: scattering ; p p: colliding beams ; B: decay ; tau: hadronic decay ; interaction: gauge ; interaction: model ; transverse momentum: missing-energy ; new physics: search for ; mass spectrum: transverse ; black hole: quantum ; vector boson: mass ; W': leptonic decay ; sensitivity ; leptoquark: coupling ; CERN LHC Coll ; leptoquark: mass: lower limit ; anomaly ; channel cross section: upper limit ; effective field theory ; Higgs

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