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Register a new userEvidence for CP violation in $B^+to p overline p K^+$ decays
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Three-body $B^+to p overline p K^+$ and $B^+to p overline p pi^+$ decays are studied using a data sample corresponding to an integrated luminosity of 3.0 $fb^{-1}$ 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 $B^+to p overline p K^+$ 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 $poverline p$ rest frame yield $A_{mathrm{FB}}(p overline p K^+,~m_{poverline p}<2.85mathrm{,Gekern -0.1em V!/}c^2)=0.495pm0.012~(mathrm{stat})pm0.007~(mathrm{syst})$ and $A_{mathrm{FB}}(poverline p pi^+,~m_{poverline p}<2.85mathrm{,Gekern -0.1em V!/}c^2)=-0.409pm0.033~(mathrm{stat})pm0.006~(mathrm{syst})$. In addition, the branching fraction of the decay $B^+tokern 0.1emoverline{kern -0.1emLambda}(1520)p$ is measured to be $mathcal{B}(B^+ to kern 0.1emoverline{kern -0.1emLambda}(1520)p)=(3.15pm0.48~(mathrm{stat})pm0.07~(mathrm{syst})pm0.26~(mathrm{BF}))times 10^{-7}$, where BF denotes the uncertainty on secondary branching fractions.
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The results of searches for $B^{0}_{(s)} rightarrow J/{psi} p overline{p}$ and $B^{+} to J/{psi} p overline{p} {pi}^{+}$ decays are reported. The analysis is based on a data sample, corresponding to an integrated luminosity of 1.0 fb$^{-1}$ of $pp$ collisions, collected with the LHCb detector. An excess with 2.8$,sigma$ significance is seen for the decay $B^{0}_{s} to J/{psi} p overline{p}$ and an upper limit on the branching fraction is set at the 90 % confidence level: ${cal B}(B^{0}_{s} to J/{psi} p overline{p}) < 4.8 times 10^{-6}$, which is the first such limit. No significant signals are seen for $B^{0} to J/{psi} p overline{p}$ and $B^{+} to J/{psi} p overline{p} {pi}^{+}$ decays, for which the corresponding limits are set: ${cal{B}}(B^{0} to J/{psi} p overline{p}) < 5.2 times 10^{-7}$, which significantly improves the existing limit; and ${cal{B}}(B^{+} to J/{psi} p overline{p} {pi}^{+}) < 5.0 times 10^{-7}$, which is the first limit on this branching fraction.
We analyze the partial rate asymmetry in $B^{pm} to P {bar P} pi^{pm}$ decays ($ P = pi^+, K ^+, pi^0, eta$) which results from the interference of the nonresonant decay amplitude and the resonant amplitude for $B^{pm} to chi_{c0} pi^{pm} $ followed by the decay $chi_{c0} to P {bar P} $. The CP violating phase $gamma$ can be extracted from the measured asymmetry. We find that the partial rate asymmetry for $B^pm to pi^+ pi^- pi^pm$ is $0.33~sin gamma$, while for $B^pm to K^+ K^-pi^pm$ it amounts $0.45~ sin gamma$.
A search for $C!P$ violation in $Lambda^0_b to p K^-$ and $Lambda^0_b to p pi^-$ decays is presented using a sample of $pp$ collisions collected with the LHCb detector and corresponding to an integrated luminosity of 3.0 fb$^{-1}$. The $C!P$-violating asymmetries are measured to be $A_{mathrm{CP}}^{pK^-} = -0.020 pm 0.013pm 0.019$ and $A_{mathrm{CP}}^{ppi^-} = -0.035 pm 0.017 pm 0.020 $, and their difference $A_{mathrm{CP}}^{pK^-}-A_{mathrm{CP}}^{ppi^-} = 0.014 pm 0.022 pm 0.010$, where the first uncertainties are statistical and the second systematic. These are the most precise measurements of such asymmetries to date.
Decays of $B^0$ and $B_{s}^0$ mesons to the charmless baryonic final states $p overline{p} h^+ h^{prime-}$, where $h$ and $h^prime$ each denote a kaon or a pion, are searched for using the LHCb detector. The analysis is based on a sample of proton-proton collision data collected at center-of-mass energies of $7$ and $8,$TeV, corresponding to an integrated luminosity of $3,$fb$^{-1}$. Four-body charmless baryonic $B_{s}^0$ decays are observed for the first time. The decays $B^0_{s}to p overline{p} K^+ K^-$, $B^0_{s}to p overline{p} K^pm pi^mp$, $B^0to p overline{p} K^pm pi^mp$ and $B^0to p overline{p} pi^+pi^-$ are observed with a significance greater than $5$ standard deviations; evidence at $4.1$ standard deviations is found for the $B^0to p overline{p} K^+ K^-$ decay and an upper limit is set on the branching fraction for $B^0_{s}to p overline{p} pi^+ pi^-$. Branching fractions in the kinematic region $m(p overline{p})<2850,$MeV$/c^2$ are measured relative to the $B^0 to J/psi (to p overline{p}) K^*(892)^0$ channel.
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