Evidence for CP Violation in B[superscript +] → p[bar over p]K[superscript +] Decays

• Main Authors: Counts, Ian Thomas Hunt (Contributor), Ilten, Philip James (Contributor), Williams, Michael (Contributor)
• Other Authors: Massachusetts Institute of Technology. Department of Physics (Contributor), Massachusetts Institute of Technology. Laboratory for Nuclear Science (Contributor)
• Format: Article
• Language: English
• Published: American Physical Society, 2014-10-09T16:13:12Z.
• Subjects: Article
• Online Access: Get fulltext

Three-body B[superscript +] → p[bar over p]K[superscript +] and B[superscript +] → p[bar over p]π[superscript +] decays are studied using a data sample corresponding to an integrated luminosity of 3.0  fb[superscript −1] collected by the LHCb experiment in proton-proton collisions at center-of-mass energies of 7 and 8 TeV. Evidence of CP violation in the B[superscript +] → p[bar over p]K[superscript +] decay is found in regions of the phase space, representing the first measurement of this kind for a final state containing baryons. Measurements of the forward-backward asymmetry of the light meson in the p[bar over p] rest frame yield A[subscript FB](p[bar over p]K[superscript +], m[subscript p[bar over p]] < 2.85  GeV/c[superscript 2]) = 0.495 ± 0.012  (stat) ± 0.007  (syst) and A[subscript FB](p[bar over p]π[superscript +], m[subscript p[bar over p]] < 2.85  GeV/c[superscript 2]) = −0.409 ± 0.033  (stat) ± 0.006  (syst). In addition, the branching fraction of the decay B[superscript +] → [bar over Λ] (1520)p is measured to be B(B[superscript +] → [bar over Λ] (1520)p) = (3.15 ± 0.48  (stat) ± 0.07  (syst) ± 0.26  (BF)) × 10[superscript −7], where BF denotes the uncertainty on secondary branching fractions.
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