اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدStudies of the decays $B^+ to p bar p h^+$ and observation of $B^+ to kern 0.1embar{kern -0.1emLambda}(1520)p$
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Dynamics and direct $CP$ violation in three-body charmless decays of charged $B$ mesons to a proton, an antiproton and a light meson (pion or kaon) are studied using data, corresponding to an integrated luminosity of 1.0$ {,fb}^{-1}$, collected by the ${LHCb}$ experiment in $pp$ collisions at a center-of-mass energy of 7 TeV. Production spectra are determined as a function of Dalitz-plot and helicity variables. The forward-backward asymmetry of the light meson in the $pbar p$ rest frame is measured. No significant $CP$ asymmetry in $B^+ to p bar p K^+$ decay is found in any region of the Dalitz plane. We present the first observation of the decay $B^+ to kern 0.1embar{kern -0.1emLambda}(1520)(to K^+bar p)p$ near the $K^+bar p$ threshold and measure $mathcal{B}(B^+ to kern 0.1embar{kern -0.1emLambda}(1520)p)=(3.9^{+1.0}_{-0.9} (mathrm{stat})pm0.1 (mathrm{syst})pm0.3 (mathrm{BF}))times 10^{-7}$, where BF denotes the uncertainty on secondary branching fractions.
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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-pr
oton 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.
The branching fractions of the decay $B^{+} to p bar p K^{+}$ for different intermediate states are measured using data, corresponding to an integrated luminosity of $1.0 fb^{-1}$, collected by the LHCb experiment. The total branching fraction, its c
harmless component $(M_{pbar p} <2.85 {GeV/}c^{2})$ and the branching fractions via the resonant $cbar c$ states $eta_{c}(1S)$ and $psi(2S)$ relative to the decay via a $J/psi$ intermediate state are {align*} frac{{mathcal B}(B^{+} to p bar p K^{+})_{total}}{{mathcal B}(B^{+} to J/psi K^{+} to p bar p K^{+})}=& , 4.91 pm 0.19 , {(rm stat)} pm 0.14 , {(rm syst)}, frac{{mathcal B}(B^{+} to p bar p K^{+})_{M_{pbar p} <2.85 {GeV/}c^{2}}}{{mathcal B}(B^{+} to J/psi K^{+} to p bar p K^{+})}=& , 2.02 pm 0.10 , {(rm stat)}pm 0.08 , {(rm syst)}, frac{{mathcal B} (B^{+} to eta_{c}(1S) K^{+} to p bar p K^{+})}{{mathcal B}(B^{+} to J/psi K^{+} to p bar p K^{+})} = & , 0.578 pm 0.035 , {(rm stat)} pm 0.027 , {(rm syst)}, frac{{mathcal B} (B^{+} to psi(2S) K^{+} to p bar p K^{+})}{{mathcal B}(B^{+} to J/psi K^{+} to p bar p K^{+})}=& , 0.080 pm 0.012 , {(rm stat)} pm 0.009 , {(rm syst)}. {align*} Upper limits on the $B^{+}$ branching fractions into the $eta_{c}(2S)$ meson and into the charmonium-like states X(3872) and X(3915) are also obtained.
Using a data sample of $772 times 10^6$ BB pairs collected on the ${Upsilon}(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider, we report the observations of $B^0to p{bar p}pi^+pi^-$ and $B^+ to p{bar p}pi^+pi^0$.
We measure a decay branching fraction of $(0.83 pm 0.17 pm 0.17) times 10^-6$ in $B^0to p{bar p}pi^+pi^-$ for $M_{pi^+pi^-} < 1.22 GeV/c^2$ with a significance of 5.5 standard deviations. The contribution from $B0 to p{bar p}K^0$ is excluded. We measure a decay branching fraction of $(4.58 pm 1.17 pm 0.67) times 10^-6$ for $B^+ to p{bar p}pi^+pi^0$ with $M_{pi^+pi^0} < 1.3 GeV/c^2$ with a significance of 5.4 standard deviations. We study the difference of the $M_{p{bar p}}$ distributions in $B^0to p{bar p}pi^+pi^-$ and $B^+ to p{bar p}pi^+pi^0$.
The first observation of the decay $eta_{c}(2S) to p bar p$ is reported using proton-proton collision data corresponding to an integrated luminosity of $3.0rm , fb^{-1}$ recorded by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. The $
eta_{c}(2S)$ resonance is produced in the decay $B^{+} to [cbar c] K^{+}$. The product of branching fractions normalised to that for the $J/psi$ intermediate state, ${cal R}_{eta_{c}(2S)}$, is measured to be begin{align*} {cal R}_{eta_{c}(2S)}equivfrac{{mathcal B}(B^{+} to eta_{c}(2S) K^{+}) times {mathcal B}(eta_{c}(2S) to p bar p)}{{mathcal B}(B^{+} to J/psi K^{+}) times {mathcal B}(J/psito p bar p)} =~& (1.58 pm 0.33 pm 0.09)times 10^{-2}, end{align*} where the first uncertainty is statistical and the second systematic. No signals for the decays $B^{+} to X(3872) (to p bar p) K^{+}$ and $B^{+} to psi(3770) (to p bar p) K^{+}$ are seen, and the 95% confidence level upper limits on their relative branching ratios are % found to be ${cal R}_{X(3872)}<0.25times10^{-2}$ and ${cal R}_{psi(3770))}<0.10$. In addition, the mass differences between the $eta_{c}(1S)$ and the $J/psi$ states, between the $eta_{c}(2S)$ and the $psi(2S)$ states, and the natural width of the $eta_{c}(1S)$ are measured as begin{align*} M_{J/psi} - M_{eta_{c}(1S)} =~& 110.2 pm 0.5 pm 0.9 rm , MeV, M_{psi(2S)} -M_{eta_{c}(2S)} =~ & 52.5 pm 1.7 pm 0.6 rm , MeV, Gamma_{eta_{c}(1S)} =~& 34.0 pm 1.9 pm 1.3 rm , MeV. end{align*}
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 co
rresponds 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.
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