A peaking structure in the J/ÏÏ mass spectrum near threshold is observed in B ±âJ/ÏÏK± decays, produced in pp collisions at âs=7 TeV collected with the CMS detector at the LHC. The data sample, selected on the basis of the dimuon decay mode of the J/Ï, corresponds to an integrated luminosity of 5.2 fb-1. Fitting the structure to an S-wave relativistic Breit-Wigner lineshape above a three-body phase-space nonresonant component gives a signal statistical significance exceeding five standard deviations. The fitted mass and width values are m = 4148.0 ± 2.4 (stat.) ± 6.3 (syst.)MeV and Î=28-11+15(stat.)±19(syst.)MeV, respectively. Evidence for an additional peaking structure at higher J/ÏÏ mass is also reported. © 2014 The Authors.
Observation of a peaking structure in the J/ÏÏ mass spectrum from B±âJ/ÏÏK± decays
ALBERGO, Sebastiano Francesco;CHIORBOLI, MASSIMILIANO;COSTA, Salvatore;GIORDANO, FERDINANDO;POTENZA, Renato Carlo;TRICOMI, Alessia Rita;TUVE', Cristina Natalina;
2014-01-01
Abstract
A peaking structure in the J/ÏÏ mass spectrum near threshold is observed in B ±âJ/ÏÏK± decays, produced in pp collisions at âs=7 TeV collected with the CMS detector at the LHC. The data sample, selected on the basis of the dimuon decay mode of the J/Ï, corresponds to an integrated luminosity of 5.2 fb-1. Fitting the structure to an S-wave relativistic Breit-Wigner lineshape above a three-body phase-space nonresonant component gives a signal statistical significance exceeding five standard deviations. The fitted mass and width values are m = 4148.0 ± 2.4 (stat.) ± 6.3 (syst.)MeV and Î=28-11+15(stat.)±19(syst.)MeV, respectively. Evidence for an additional peaking structure at higher J/ÏÏ mass is also reported. © 2014 The Authors.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.