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تسجيل مستخدم جديدObservation of the decay $B_c rightarrow J/psi K^+ K^- pi^+ $
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The decay $B_crightarrow J/psi K^+ K^- pi^+$ is observed for the first time, using proton-proton collisions collected with the LHCb detector corresponding to an integrated luminosity of 3fb$^{-1}$. A signal yield of $78pm14$ decays is reported with a significance of 6.2 standard deviations. The ratio of the branching fraction of $B_c rightarrow J/psi K^+ K^- pi^+$ decays to that of $B_c rightarrow J/psi pi^+$ decays is measured to be $0.53pm 0.10pm0.05$, where the first uncertainty is statistical and the second is systematic.
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The decay $overline{B}_s^0 rightarrow psi(2S) K^+ pi^-$ is observed using a data set corresponding to an integrated luminosity of $3.0fb^{-1}$ collected by the LHCb experiment in $pp$ collisions at centre-of-mass energies of 7 and 8 TeV. The branchin
g fraction relative to the $B^0rightarrow psi(2S) K^+ pi^-$ decay mode is measured to be begin{equation} frac{{cal B}(overline{B}^0_s rightarrow psi(2S) K^+ pi^-)}{{cal B}(B^0 rightarrow psi(2S) K^+ pi^-)} = 5.38 pm 0.36 (stat) pm 0.22 (syst) pm 0.31 , (f_s/f_d) , %, onumber end{equation} where $f_s/f_d$ indicates the uncertainty due to the ratio of probabilities for a $b$ quark to hadronise into a $B_s^0$ or $B^0$ meson. Using an amplitude analysis, the fraction of decays proceeding via an intermediate $K^*(892)^0$ meson is measured to be $0.645 pm 0.049 (stat) pm 0.049 (syst)$ and its longitudinal polarisation fraction is $0.524 pm 0.056 (stat) pm 0.029 (syst)$. The relative branching fraction for this component is determined to be begin{equation} frac{{cal B}(overline{B}^0_s rightarrow psi(2S) K^*(892)^0)}{{cal B}(B^0 rightarrow psi(2S) K^*(892)^0)} = 5.58 pm 0.57 (stat) pm 0.40 (syst) pm 0.32 , (f_s/f_d) , %. onumber end{equation} In addition, the mass splitting between the $B_s^0$ and $B^0$ mesons is measured as begin{equation} M(B^0_s) - M(B^0) = 87.45 pm 0.44 (stat) pm 0.07 (syst) MeV/c^2. onumber end{equation}
Decays of the form $B^{0}_{(s)}rightarrow J/psi K_{{rm S}}^{0} h^+ h^{left(primeright) -}$ ($h^{(prime)} = K, pi$) are searched for in proton-proton collision data corresponding to an integrated luminosity of $1.0 , {rm fb}^{-1}$ recorded with the LH
Cb detector. The first observation of the $B^{0}_{s}rightarrow J/psi K_{{rm S}}^{0} K^{pm} pi^{mp}$ decay is reported, with significance in excess of 10 standard deviations. The $B^{0}rightarrow J/psi K_{{rm S}}^{0} K^{+} K^{-}$ decay is also observed for the first time. The branching fraction of $B^{0}rightarrow J/psi K_{{rm S}}^{0} pi^{+} pi^{-}$ is determined, to significantly better precision than previous measurements, using $B^0 rightarrow J/psi K_{{rm S}}^{0}$ as a normalisation channel. Branching fractions and upper limits of the other $B^{0}_{(s)}rightarrow J/psi K_{{rm S}}^{0} h^+ h^{left(primeright) -}$ modes are determined relative to that of the $B^{0}rightarrow J/psi K_{{rm S}}^{0} pi^{+} pi^{-}$ decay.
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.
Evidence is presented for the decay $B_c+rightarrow J/psi 3pi^+2pi^-$ using proton-proton collision data, corresponding to an integrated luminosity of 3fb$^{-1}$, collected with the LHCb detector. A signal yield of $32pm8$ decays is found with a sign
ificance of 4.5 standard deviations. The ratio of the branching fraction of the $B_c^+rightarrow J/psi 3pi^+ 2pi^-$ decay to that of the $B_c^+ rightarrow J/psi pi^+$ decay is measured to be $$ frac{Br (B_c^+ rightarrow J/psi 3pi^+2pi^)}{Br (B_c^+ rightarrow J/psi pi^+)} = 1.74pm0.44pm0.24, $$ where the first uncertainty is statistical and the second is systematic.
One of the most intriguing puzzles in hadron spectroscopy are the numerous charmonium-like states observed in the last decade, including charged states that are manifestly exotic. Over the years, the experiment $BABAR$ has extensively studied those i
n B meson decays, initial state radiation processes and two photon reactions. We report in this paper a new study on some of those states, performed using the entire data sample collected by $BABAR$ in $e^+e^-$ collisions, at center of mass energies near 10.58 GeV/c$^2$. The study of the process $B rightarrow J/psi phi K$ will be presented, and the search for the resonant states X(4140) and X(4270) in their decays to $J/psi phi$, will be highlighted.
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