Publications associated with TORCH

Measurement of CP violation in B-0 -> J/psi K-S(0) and B-0 -> psi(2S) K-S(0) decays

Journal of High Energy Physics Springer Verlag 2017 (2017) 1-18

R Aaij, B Adeva, M Bjørn, M Adinolfi, SF Cheung, T Evans, BRG Cazon, T Hadavizadeh, N Harnew, TH Hancock, J Jalocha, D Hill, N Jurik, M John, S Malde, A Nandi, H Pullen, A Rollings, G Veneziano, M Vesterinen, G Wilkinson

A measurement is presented of decay-time-dependent CP violation in the decays B 0 → J/ψ K S 0 and B 0 → ψ(2S)K S 0 , where the J/ψ is reconstructed from two electrons and the ψ(2S) from two muons. The analysis uses a sample of pp collision data recorded with the LHCb experiment at centre-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb −1 . The CP -violation observables are measured to beC(B0→J/ψKS0)=0.12±0.07±0.02,S(B0→J/ψKS0)=0.83±0.08±0.01,C(B0→ψ(2S)KS0)=−0.05±0.10±0.01,S(B0→ψ(2S)KS0)=0.84±0.10±0.01,where C describes CP violation in the direct decay, and S describes CP violation in the interference between the amplitudes for the direct decay and for the decay after B 0 − B¯ 0 oscillation. The first uncertainties are statistical and the second are systematic. The two sets of results are compatible with the previous LHCb measurement using B 0 → J/ψ K S 0 decays, where the J/ψ meson was reconstructed from two muons. The averages of all three sets of LHCb results areC(B0→[cc¯]KS0)=−0.017±0.029,S(B0→[cc¯] KS0)=0.760±0.034,under the assumption that higher-order contributions to the decay amplitudes are negligible. The uncertainties include statistical and systematic contributions.[Figure not available: see fulltext.].

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