Evidence for CP violation in $B^{+}\to p\bar{p}{K}^{+}$ decays

Three-body $B^{+}\to p\bar{p}{K}^{+}$ and $B^{+}\to p\bar{p}{\pi }^{+}$ decays are studied using a data sample corresponding to an integrated luminosity of 3.0 $f{b}^{-1}$ 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 $B^{+}\to p\bar{p}{K}^{+}$ 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 $p\bar{p}$ rest frame yield $A_{$\mathrm{F}\mathrm{B}$}(p \overline p K^+,~m_{p\overline p}<2.85\mathrm{,Ge\kern -0.1em V!/}c^2)=0.495\pm0.012~($\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t}$)\pm0.007~($\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t}$)$and$A_{$\mathrm{F}\mathrm{B}$}(p\overline p \pi^+,~m_{p\overline p}<2.85\mathrm{,Ge\kern -0.1em V!/}c^2)=-0.409\pm0.033~($\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t}$)\pm0.006~($\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t}$)$. In addition, the branching fraction of the decay $B^+\to\kern 0.1em\overline{\kern -0.1em\Lambda}(1520)p$ismeasuredtobe$$\mathcal{B}$(B^+ \to \kern 0.1em\overline{\kern -0.1em\Lambda}(1520)p)=(3.15\pm0.48~($\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t}$)\pm0.07~($\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t}$)\pm0.26~($\mathrm{B}\mathrm{F}$))\times 10^{-7}$, where BF denotes the uncertainty on secondary branching fractions.