Aad, G.ATLAS Collaboration,2016-11-012016-11-012014Physical Review Letters, 2014; 113(21):212004-1-212004-181079-71141079-7114http://hdl.handle.net/2440/102102A search for excited states of the B+/- c meson is performed using 4.9fb -1 of 7 TeV and 19.2fb -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/psi pi +/-. The state appears in the m(B+/- c pi+pi -)- m(B+/- c)-2m(pi +/-) mass difference distribution with a significance of 5.2 standard deviations. The mass of the observed state is 6842+/-4+/-5MeV, 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 B+/- c meson, B+/- c(2S).en© 2014 CERN, for the ATLAS Collaboration. This article is available under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.ATLAS CollaborationJournal article003001890810.1103/PhysRevLett.113.2120040003457458000022-s2.0-849798422802-s2.0-84915745663162047