A search for excited states of the B c meson is performed using 4.9 fb−1 of 7 TeVand 19.2 fb−1 of 8 TeV pp collision data collected by the ATLAS experiment at the LHC. A new state is observed through its hadronic transition to the ground state, with the latter detected in the decay B c → J=ψπ. The state appears in the mðB c πþπ−Þ − mðB c Þ − 2mðπÞ mass difference distribution with a significance of 5.2 standard deviations. The mass of the observed state is 6842 4 5 MeV, where the first error is statistical and the second is systematic. The mass and decay of this state are consistent with expectations for the second S-wave state of the Bc meson, Bc ð2SÞ.
Observation of an excited B±c meson state with the ATLAS detector
CONTA, CLAUDIO;DONDERO, PAOLO;FRATERNALI, MARCO;LIVAN, MICHELE;NEGRI, ANDREA;REBUZZI, DANIELA MARCELLA;RIMOLDI, ADELE;
2014-01-01
Abstract
A search for excited states of the B c meson is performed using 4.9 fb−1 of 7 TeVand 19.2 fb−1 of 8 TeV pp collision data collected by the ATLAS experiment at the LHC. A new state is observed through its hadronic transition to the ground state, with the latter detected in the decay B c → J=ψπ. The state appears in the mðB c πþπ−Þ − mðB c Þ − 2mðπÞ mass difference distribution with a significance of 5.2 standard deviations. The mass of the observed state is 6842 4 5 MeV, where the first error is statistical and the second is systematic. The mass and decay of this state are consistent with expectations for the second S-wave state of the Bc meson, Bc ð2SÞ.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
