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Register a new userFirst evidence for the two-body charmless baryonic decay $B^0 to p bar{p}$
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The results of a search for the rare two-body charmless baryonic decays $B^0 to p bar{p}$ and $B_s^0 to p bar{p}$ are reported. The analysis uses a data sample, corresponding to an integrated luminosity of 0.9 fb$^{-1}$, of $pp$ collision data collected by the LHCb experiment at a centre-of-mass energy of 7 TeV. An excess of $B^0 to p bar{p}$ candidates with respect to background expectations is seen with a statistical significance of 3.3 standard deviations. This is the first evidence for a two-body charmless baryonic $B^0$ decay. No significant $B_s^0 to p bar{p}$ signal is observed, leading to an improvement of three orders of magnitude over previous bounds. If the excess events are interpreted as signal, the 68.3% confidence level intervals on the branching fractions are {eqnarray} cal{B}(B^0 to p bar{p}) & = & (1.47 ,^{+0.62}_{-0.51} ,^{+0.35}_{-0.14}) times 10^{-8} ,, *{0.3cm} cal{B}(B_s^0 to p bar{p}) & = & (2.84 ,^{+2.03}_{-1.68} ,^{+0.85}_{-0.18}) times 10^{-8} ,, {eqnarray} where the first uncertainty is statistical and the second is systematic.
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A search for the rare two-body charmless baryonic decay $B^+ to p barLambda$ is performed with $pp$ collision data, corresponding to an integrated luminosity of $3,mbox{fb}^{-1}$, collected by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. An excess of $B^+ to p barLambda$ candidates with respect to background expectations is seen with a statistical significance of 4.1 standard deviations, and constitutes the first evidence for this decay. The branching fraction, measured using the $B^+ to K^0_{mathrm S} pi^+$ decay for normalisation, is begin{eqnarray} mathcal{B}(B^+ to p barLambda) & = & ( 2.4 ,^{+1.0}_{-0.8} pm 0.3 ) times 10^{-7} ,, onumber end{eqnarray} where the first uncertainty is statistical and the second systematic.
The first observation of the decay of a $B^0$ meson to a purely baryonic final state, $B^0 to p bar{p}$, is reported. The proton-proton collision data sample used was collected with the LHCb experiment at center-of-mass energies of 7 and 8 TeV and corresponds to an integrated luminosity of 3.0 fb$^{-1}$. The branching fraction is determined to be $${cal B}(B^0 to p bar{p}) = ( 1.25 pm 0.27 pm 0.18 ) times 10^{-8} ,$$ where the first uncertainty is statistical and the second systematic. The decay mode $B^0 to p bar{p}$ is the rarest decay of the $B^0$ meson observed to date. The decay $B_s^0 to p bar{p}$ is also investigated. No signal is seen and the upper limit ${cal B}(B_s^0 to p bar{p}) < 1.5 times 10^{-8}$ at 90% confidence level is set on the branching fraction.
We report a search for the charmless baryonic decay $B^0to pbar{p}pi^0$ with a data sample corresponding to an integrated luminosity of 711~$rm fb^{-1}$ containing $(772pm 10)times 10^6$ $B^0bar{B}^0$ pairs. The data was collected by the Belle experiment running on the $Upsilon(4S)$ resonance at the KEKB $e^+e^-$ collider. We measure a branching fraction $mathcal{B}(B^0to pbar{p}pi^0)= (5.0pm1.8pm0.6 )times 10^{-7}$, where the first uncertainty is statistical and the second is systematic. The signal has a significance of 3.1 standard deviations and constitutes the first evidence for this decay mode. We also search for the intermediate two-body decays $B^{0}toDelta^+bar{p}$ and $B^0tobar{Delta}^-p$, and set an upper limit on the branching fraction: $mathcal{B}(B^0to Delta^+bar{p})+mathcal{B}(B^0tobar{Delta}^-p)<1.6times10^{-6}$ at 90% confidence level.
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.
An amplitude analysis of flavour-untagged $B_s^0 to J/psi p bar{p}$ decays is performed using a sample of $797pm31$ decays reconstructed with the LHCb detector. The data, collected in proton-proton collisions between 2011 and 2018, correspond to an integrated luminosity of 9 $text{fb}^{-1}$. Evidence for a new structure in the $J/psi p$ and $J/psi bar{p}$ systems with a mass of $4337 ^{+7}_{-4} ^{+2}_{-2}~text{MeV}$ and a width of $29 ^{+26}_{-12} ^{+14}_{-14}~text{MeV}$ is found, where the first uncertainty is statistical and the second systematic, with a significance in the range of 3.1 to 3.7 $sigma$, depending on the assigned $J^P$ hypothesis.
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