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Register a new userMeasurement of the branching fraction and $C!P$ asymmetry in $B^{+}rightarrow J/psi rho^{+}$ decays
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The branching fraction and direct $C!P$ asymmetry of the decay $B^{+}rightarrow J/psi rho^{+}$ are measured using proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7 and 8 TeV, corresponding to a total integrated luminosity of 3$mbox{fb}^{-1}$. The following results are obtained: begin{align} mathcal{B}(B^{+}rightarrow J/psi rho^{+}) &= (3.81 ^{+0.25}_{-0.24} pm 0.35) times 10^{-5}, onumber mathcal{A}^{C!P} (B^{+}rightarrow J/psi rho^{+}) &= -0.045^{+0.056}_{-0.057} pm 0.008, onumber end{align} where the first uncertainties are statistical and the second systematic. Both measurements are the most precise to date.
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Using $pp$ collision data collected by LHCb at center-of-mass energies $sqrt{s}$ = 7 TeV and 8 TeV, corresponding to an integrated luminosity of 3 fb$^{-1}$, the ratio of the branching fraction of the $B_c^+ rightarrow psi(2S)pi^+$ decay relative to that of the $B_c^+ rightarrow J/psipi^+$ decay is measured to be 0.268 $pm$ 0.032 (stat) $pm$ 0.007 (syst) $pm$ 0.006 (BF). The first uncertainty is statistical, the second is systematic, and the third is due to the uncertainties on the branching fractions of the $J/psi rightarrow mu^+mu^-$ and $psi(2S) rightarrow mu^+mu^-$ decays. This measurement is consistent with the previous LHCb result, and the statistical uncertainty is halved.
Using a sample of $1.31 times 10^{9}$ $J/psi$ events collected with the BESIII detector at the BEPCII collider, we study the decays of $J/psi rightarrow K_S K_L$ and $K_S K_S$. The branching fraction of$J/psirightarrow K_S K_L$ is determined to be ${cal B}(J/psi rightarrow K_S K_L)=(1.93pm0.01~(rm{stat.})pm0.05~(rm{syst.}))times10^{-4}$, which significantly improves on previous measurements. No clear signal is observed for the $J/psi rightarrow K_S K_S$ process, and the upper limit at the 95% confidence level for its branching fraction is determined to be ${cal B}(J/psi rightarrow K_S K_S)<1.4times10^{-8}$, which improves on the previous searches by two orders in magnitude and reaches the order of the Einstein-Podolsky-Rosen expectation.
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 measure the branching fraction and time-dependent $CP$-violating asymmetry for $B^0to J/psipi^0$ decays using a data sample of 711 ${rm fb^{-1}}$ collected on the $Upsilon(4S)$ resonance by the Belle experiment running at the KEKB $e^+e^-$ collider. The branching fraction is measured to be $mathcal{B}(B^0to J/psipi^0) = [1.62,pm 0.11~({rm stat}) pm0.07~({rm syst})]times 10^{-5}$, which is the most precise measurement to date. The measured $CP$ asymmetry parameters are $mathcal{S} = -0.59,pm 0.19~({rm stat}) pm 0.03~({rm syst})$ and $mathcal{A} = -0.15,pm 0.14~({rm stat}),^{+0.04}_{-0.03}~({rm syst})$. The mixing-induced $CP$ asymmetry ($mathcal{S}$) differs from the case of no $CP$ violation by 3.0 standard deviations, and the direct $CP$ asymmetry ($mathcal{A}$) is consistent with zero.
A search for the decay $B^0_srightarrow J/psi K^{*0}$ with $K^{*0} rightarrow K^-pi^+$ is performed with 0.37 fb$^{-1}$ of $pp$ collisions at $sqrt{s}$ = 7 TeV collected by the LHCb experiment, finding a $Bs to Jpsi K^-pi^+$ peak of $114 pm 11$ signal events. The $K^-pi^+$ mass spectrum of the candidates in the $B^0_s$ peak is dominated by the $K^{*0}$ contribution. Subtracting the non-resonant $K^-pi^+$ component, the branching fraction of BsJpsiKst is $(4.4_{-0.4}^{+0.5} pm 0.8) times 10^{-5}$, where the first uncertainty is statistical and the second systematic. A fit to the angular distribution of the decay products yields the Kst polarization fractions $f_L = 0.50 pm 0.08 pm 0.02$ and $f_{||} = 0.19^{+0.10}_{-0.08} pm 0.02$.
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