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Register a new userEvidence for $B^+ rightarrow h_c K^+$ and observation of $eta_c(2S) to p bar{p} pi^+ pi^-$
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A search for the decays $B^+ rightarrow h_c K^+$ and $B^0 rightarrow h_c K_S^0$ is performed. Evidence for the decay $B^+ rightarrow h_c K^+$ is found; its significance is $4.8sigma$. No evidence is found for $B^0 rightarrow h_c K_S^0$. The branching fraction for $B^+ rightarrow h_c K^+$ is measured to be $(3.7^{+1.0}_{-0.9}{}^{+0.8}_{-0.8}) times 10^{-5}$; the upper limit for the $B^0 rightarrow h_c K_S^0$ branching fraction is $1.4 times 10^{-5}$ at $90%$ C.L. In addition, a study of the $p bar{p} pi^+ pi^-$ invariant mass distribution in the channel $B^+ to (p bar{p} pi^+ pi^-) K^+$ results in the first observation of the decay $eta_c(2S) to p bar{p} pi^+ pi^-$ with $12.1sigma$ significance. The analysis is based on the 711 $mathrm{fb}^{-1}$ data sample collected by the Belle detector at the asymmetric-energy $e^+ e^-$ collider KEKB at the $Upsilon(4S)$ resonance.
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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 decays $B^+rightarrow J/psi 3pi^+ 2pi^-$ and $B^+rightarrow psi(2S) pi^+pi^+pi^-$ are observed for the first time using a data sample corresponding to an integrated luminosity of $3.0fb^{-1}$, collected by the LHCb experiment in proton-proton collisions at the centre-of-mass energies of 7 and 8 TeV. The branching fractions relative to that of $B^+ rightarrow psi(2S)K^+$ are measured to be begin{eqnarray*} frac {mathcal{B}left(B^+rightarrow J/psi 3pi^+ 2pi^- right)} {mathcal{B}left(B^+ rightarrow psi(2S)K^+ right)} & = & left(1.88pm0.17pm0.09right)times10^{-2}, frac {mathcal{B}left(B^+rightarrow psi(2S) pi^+pi^+pi^- right)} {mathcal{B}left(B^+ rightarrow psi(2S)K^+ right)} & = & left(3.04pm0.50pm0.26right)times10^{-2}, end{eqnarray*} where the first uncertainties are statistical and the second are systematic.
The ratios of the branching fractions of the decays $Lambda_{c}^{+} rightarrow p pi^{-} pi^{+}$, $Lambda_{c}^{+} rightarrow p K^{-} K^{+}$, and $Lambda_{c}^{+} rightarrow p pi^{-} K^{+}$ with respect to the Cabibbo-favoured $Lambda_{c}^{+} rightarrow p K^{-} pi^{+}$ decay are measured using proton-proton collision data collected with the LHCb experiment at a 7 TeV centre-of-mass energy and corresponding to an integrated luminosity of 1.0 fb$^{-1}$: begin{align*} frac{mathcal{B}(Lambda_{c}^{+} rightarrow p pi^{-} pi^{+})}{mathcal{B}(Lambda_{c}^{+} rightarrow p K^{-} pi^{+})} & = (7.44 pm 0.08 pm 0.18),%, frac{mathcal{B}(Lambda_{c}^{+} rightarrow p K^{-} K^{+})}{mathcal{B}(Lambda_{c}^{+} rightarrow p K^{-} pi^{+})} &= (1.70 pm 0.03 pm 0.03),%, frac{mathcal{B}(Lambda_{c}^{+} rightarrow p pi^{-} K^{+})}{mathcal{B}(Lambda_{c}^{+} rightarrow p K^{-} pi^{+})} & = (0.165 pm 0.015 pm 0.005 ),%, end{align*} where the uncertainties are statistical and systematic, respectively. These results are the most precise measurements of these quantities to date. When multiplied by the world-average value for $mathcal{B}(Lambda_{c}^{+} rightarrow p K^{-} pi^{+})$, the corresponding branching fractions are begin{align*} mathcal{B}(Lambda_{c}^{+} rightarrow p pi^{-} pi^{+}) &= (4.72 pm 0.05 pm 0.11 pm 0.25) times 10^{-3}, mathcal{B}(Lambda_{c}^{+} rightarrow p K^{-} K^{+}) &= (1.08 pm 0.02 pm 0.02 pm 0.06) times 10^{-3}, mathcal{B}(Lambda_{c}^{+} rightarrow p pi^{-} K^{+}) &= (1.04 pm 0.09 pm 0.03 pm 0.05) times 10^{-4}, end{align*} where the final uncertainty is due to $mathcal{B}(Lambda_{c}^{+} rightarrow p K^{-} pi^{+})$.
We report the study of OK and SK using a $772 times 10^6$ $Bbar{B}$ pair data sample recorded on the $Upsilon({rm 4S})$ resonance with the Belle detector at KEKB. The following branching fractions are measured: $mathcal{B}$(OKPHSP) $=$ $(4.22^{+0.45}_{-0.44}pm 0.51)times10^{-6}$, $mathcal{B}$(SKPHSP) $=$ $(3.81^{+0.39}_{-0.37} pm 0.45)times 10^{-6}$, $mathcal{B}$(ETACD+c.c.) $=$ $(2.91^{+0.37}_{-0.35}pm 0.36)times 10^{-3}$ and $mathcal{B}$(PLPHI) $=$ $(8.18 pm 2.15 pm 0.79)times10^{-7}$, where c.c. denotes the corresponding charge-conjugation process. The intermediate resonance decays are excluded in the four-body decay measurements. We also found evidences for $mathcal{B}$(ETACS+c.c.) $=$ $(3.59 pm 1.52 pm 0.47) times 10^{-3}$ and $mathcal{B}$(LLKO) $=$ $(2.30 pm 0.65 pm 0.25) times 10^{-6}$. No significant signals are found for JPSIS+c.c. and LLKS ; we set the 90% confidence level upper limits on their decay branching fractions as $< 1.85times10^{-3}$ and $< 2.14times10^{-6}$, respectively.
A Dalitz plot analysis of $B^0 to eta_c(1S) K^+pi^-$ decays is performed using data samples of $pp$ collisions collected with the LHCb detector at centre-of-mass energies of $sqrt{s}=7,~8$ and $13$ TeV, corresponding to a total integrated luminosity of $4.7~text{fb}^{-1}$. A satisfactory description of the data is obtained when including a contribution representing an exotic $eta_c(1S) pi^-$ resonant state. The significance of this exotic resonance is more than three standard deviations, while its mass and width are $4096 pm 20~^{+18}_{-22}$ MeV and $152 pm 58~^{+60}_{-35}$ MeV, respectively. The spin-parity assignments $J^P=0^+$ and $J^{P}=1^-$ are both consistent with the data. In addition, the first measurement of the $B^0 to eta_c(1S) K^+pi^-$ branching fraction is performed and gives $displaystyle mathcal{B}(B^0 to eta_c(1S) K^+pi^-) = (5.73 pm 0.24 pm 0.13 pm 0.66) times 10^{-4}$, where the first uncertainty is statistical, the second systematic, and the third is due to limited knowledge of external branching fractions.
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