A search for excited states of the Bc+/- meson is performed using 4.9 inv. fb of 7 TeV and 19.2 inv. fb 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 Bc+/- -> J/psi pi+/-. The state appears in the m(Bc+/- pi+ pi-) - m(Bc+/-) - 2m(pi+/-) 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, Bc(2S).
Observation of an Excited Bc+- Meson State with the ATLAS Detector
GORINI, Edoardo;PRIMAVERA, Margherita;SPAGNOLO, Stefania Antonia;VENTURA, Andrea
2014-01-01
Abstract
A search for excited states of the Bc+/- meson is performed using 4.9 inv. fb of 7 TeV and 19.2 inv. fb 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 Bc+/- -> J/psi pi+/-. The state appears in the m(Bc+/- pi+ pi-) - m(Bc+/-) - 2m(pi+/-) 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, Bc(2S).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
