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Register a new userFirst observation of the decays $bar{B}^0_{(s)}to D_s^+K^-pi^+pi^-$ and $bar{B}^0_sto D_{s1}(2536)^+pi^-$
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The first observation of the decays $bar{B}^0_{s}to D_s^+K^-pi^+pi^-$ and $bar{B}^0to D_s^+K^-pi^+pi^-$ are reported using an integrated luminosity of 1.0 fb$^{-1}$ recorded by the LHCb experiment. The branching fractions, normalized with respect to $bar{B}^0_{s}to D_s^+pi^-pi^+pi^-$ and $bar{B}^0_{s}to D_s^+K^-pi^+pi^-$, respectively, are measured to be {br(bar{B}^0_{s}to D_s^+K^-pi^+pi^-)overbr(bar{B}^0_{s}to D_s^+pi^-pi^+pi^-)} &= (5.2pm0.5pm0.3)times10^{-2}, {br(bar{B}^0to D_s^+K^-pi^+pi^-)overbr(bar{B}^0_{s}to D_s^+K^-^pi^+pi^-)} &= 0.54pm0.07pm0.07, where the first uncertainty is statistical and the second is systematic. The $bar{B}^0_{s}to D_s^+K^-pi^+pi^-$ decay is of particular interest as it can be used to measure the weak phase $gamma$. First observation of the $bar{B}^0_sto D_{s1}(2536)^+pi^-, D_{s1}^+to D_s^+pi^-pi^+$ decay is also presented, and its branching fraction relative to $bar{B}^0_{s}to D_s^+pi^-pi^+pi^-$ is found to be {br(bar{B}^0_sto D_{s1}(2536)^+pi^-, D_{s1}^+to D_s^+pi^-pi^+)overbr(bar{B}^0_{s}to D_s^+pi^-pi^+pi^-)} &= (4.0pm1.0pm0.4)times10^{-3}.
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First observations of the Cabibbo suppressed decays B0bar -->D+ K- pi+ pi- and B- --> D0 K- pi+ pi- are reported using 35 pb^{-1} of data collected with the LHCb detector. Their branching fractions are measured with respect to the corresponding Cabibbo favored decays, from which we obtain B(B0bar --> D+ K- pi+ pi-)/B(B0bar --> D+ pi- pi+ pi-)=(5.9pm1.1pm0.5) x 10^{-2} and B(B- --> D0 K- pi+ pi-)/B(B- --> D0 pi- pi+ pi-)=(9.4pm1.3pm0.9) x 10^{-2}, where the uncertainties are statistical and systematic, respectively. The B- --> D0 K- pi+ pi- decay is particularly interesting, as it can be used in a similar way to B- --> D0 K- to measure the CKM phase gamma.
A search for previously unobserved decays of beauty baryons to the final states $K^0_{rmscriptscriptstyle S} p pi^{-}$ and $K^0_{rmscriptscriptstyle S}p K^{-}$ is reported. The analysis is based on a data sample corresponding to an integrated luminosity of $1.0,$fb$^{-1}$ of $pp$ collisions. The $Lambda^0_{b} rightarrow overline{kern -0.2em K}^0_{rmscriptscriptstyle S}p pi^{-}$ decay is observed with a significance of $8.6,sigma$, with branching fraction begin{eqnarray*} {cal{B}}(Lambda^0_{b} rightarrow overline{kern -0.2em K}^0 p pi^{-}) & = & left(1.26 pm 0.19 pm 0.09 pm 0.34 pm 0.05 right) times 10^{-5} ,, end{eqnarray*} where the uncertainties are statistical, systematic, from the ratio of fragmentation fractions $f_{Lambda}/f_{d}$, and from the branching fraction of the $B^0 rightarrow K^0_{rmscriptscriptstyle S}pi^{+}pi^{-}$ normalisation channel, respectively. A first measurement is made of the $CP$ asymmetry, giving begin{eqnarray*} A_{C/!P} (Lambda^0_{b} rightarrow overline{kern -0.2em K}^0 p pi^{-}) & = & 0.22 pm 0.13mathrm{,(stat)} pm 0.03mathrm{,(syst)} , . end{eqnarray*} No significant signals are seen for $Lambda^0_{b} rightarrow K^0_{rmscriptscriptstyle S}p K^{-}$ decays, $Xi^{0}_{b}$ decays to both the $K^0_{rmscriptscriptstyle S}p pi^{-}$ and $K^0_{rmscriptscriptstyle S}p K^{-}$ final states, and the $Lambda^0_{b} rightarrow D^{-}_{s} (rightarrow K^0_{rmscriptscriptstyle S} K^{-}) p$ decay, and upper limits on their branching fractions are reported.
Within the quasi-two-body decay model, we study the localized $CP$ violation and branching fraction of the four-body decay $bar{B}^0rightarrow [K^-pi^+]_{S/V}[pi^+pi^-]_{V/S} rightarrow K^-pi^+pi^-pi^+$ when $K^-pi^+$ and $pi^-pi^+$ pair invariant masses are $0.35<m_{K^-pi^+}<2.04 , mathrm{GeV}$ and $0<m_{pi^-pi^+}<1.06, mathrm{GeV}$, with the pairs being dominated by the $bar{K}^*_0(700)^0$, $bar{K}^*(892)^0$, $bar{K}^*(1410)^0$, $bar{K}^*_0(1430)$ and $bar{K}^*(1680)^0$, and $f_0(500)$, $rho^0(770)$ , $omega(782)$ and $f_0(980)$ resonances, respectively. When dealing with the dynamical functions of these resonances, $f_0(500)$, $rho^0(770)$, $f_0(980)$ and $bar{K}^*_0(1430)$ are modeled with the Bugg model, Gounaris-Sakurai function, Flatt$acute{mathrm{e}}$ formalism and LASS lineshape, respectively, while others are described by the relativistic Breit-Wigner function. Adopting the end point divergence parameters $rho_Ain[0,0.5]$ and $phi_Ain[0,2pi]$, our predicted results are $mathcal{A_{CP}}(bar{B}^0rightarrow K^-pi^+pi^+pi^-)in[-0.383,0.421]$ and $mathcal{B}(bar{B}^0rightarrow K^-pi^+pi^+pi^-)in[7.36,199.69]times10^{-8}$ based on the hypothetical $qbar{q}$ structures for the scalar mesons in the QCD factorization approach. Meanwhile, we calculate the $CP$ violating asymmetries and branching fractions of the two-body decays $bar{B}^0rightarrow SV(VS)$ and all the individual four-body decays $bar{B}^0rightarrow SV(VS) rightarrow K^-pi^+pi^-pi^+$, respectively. Our theoretical results for the two-body decays $bar{B}^0rightarrow bar{K}^*(892)^0$$f_0(980)$, $bar{B}^0rightarrow bar{K}^*_0(1430)^0$$omega(782)$, $bar{B}^0rightarrow bar{K}^*(892)^0f_0(980)$, $bar{B}^0rightarrowbar{K}^*_0(1430)^0rho$,
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 $B^+ to p{bar p}pi^+pi^0$.
First observations of the $B^0_s rightarrow psi(2S) eta$, $B^0 rightarrow psi(2S) pi^+ pi^-$ and $B^0_s rightarrow psi(2S) pi^+ pi^-$ decays are made using a dataset corresponding to an integrated luminosity of 1.0~$fb^{-1}$ collected by the LHCb experiment in proton-proton collisions at a centre-of-mass energy of $sqrt{s}=7$ TeV. The ratios of the branching fractions of each of the $psi(2S)$ modes with respect to the corresponding $J/psi$ decays are [ frac{mathcal{B}(B^0_s rightarrow psi(2S) eta) }{mathcal{B}(B^0_s rightarrow J/psi eta)} =0.83pm0.14,(stat)pm0.12,(syst)pm0.02,(mathcalB}), ] [ frac{mathcal{B}(B^0 rightarrow psi(2S) pi^+ pi^-)}{mathcal{B}(B^0 rightarrow J/psi pi^+ pi^-)} =0.56pm0.07,(stat)pm0.05,(syst)pm0.01,(mathcal{B}), ] [ frac{mathcal{B}(B^0_s rightarrow psi(2S) pi^+ pi^-)}{mathcal{B}(B^0_s rightarrow J/psi pi^+ pi^-)} =0.34pm0.04,(stat)pm0.03,(syst)pm0.01,(mathcal{B}), ] where the third uncertainty corresponds to the uncertainties of the dilepton branching fractions of the $J/psi$ and $psi(2S)$ meson decays.
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