PT Journal AU LHCb Collaboration (Aaij, Rea Garcia Martin, LM Henry, L Martinez-Vidal, F Oyanguren, A Remon Alepuz, C Ruiz Vidal, J Sanchez Mayordomo, C TI Evidence for an etac(1S)pi- resonance in B0 etac(1S)K+pi- decays SO European Physical Journal C JI Eur. Phys. J. C PY 2018 BP 1019 EP 23pp VL 78 IS 12 DI 10.1140/epjc/s10052-018-6447-z LA English AB A Dalitz plot analysis of /30 ric(1S)K+7decays is performed using data samples of pp collisions collected with the LHCb detector at centre -of -mass energies of./7 = 7, 8 and 13 TeV, corresponding to a total integrated luminosity of 4.7 fb-1. A satisfactory description of the data is obtained when including a contribution representing an exotic qc (1 S).7-- resonant state. The significance of this exotic resonance is more than three standard deviations, while its mass and width are 4096 20 is MeV and 152 +58 -P6 MeV, respectively. The spin -parity assignments JP = 0+ and JP = 1- are both consistent with the data. In addition, the first measurement of the B -> ric(1S)K+71-branching fraction is performed and gives B(B -> = (5.73 0.24 0.13 0.66) x 10-4, where the first uncertainty is statistical, the second systematic, and the third is due to limited knowledge of external branching fractions. ER