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Register a new userFirst study of the CP-violating phase and decay-width difference in $B_s^0topsi(2S)phi$ decays
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A time-dependent angular analysis of $B_s^0topsi(2S)phi$ decays is performed using data recorded by the LHCb experiment. The data set corresponds to an integrated luminosity of 3.0invfb collected during Run 1 of the LHC. The CP-violating phase and decay-width difference of the $B_s^0$ system are measured to be $phi_s = 0.23^{+0.29}_{-0.28} pm 0.02$ rad and $DeltaGamma_s = 0.066^{+0.041}_{-0.044} pm 0.007$ ps$^{-1}$, respectively, where the first uncertainty is statistical and the second systematic. This is the first time that $phi_s$ and $DeltaGamma_s$ have been measured in a decay containing the $psi(2S)$ resonance.
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A first flavour-tagged measurement of the time-dependent CP-violating asymmetry in $B_s^0 to phiphi$ decays is presented. In this decay channel, the CP-violating weak phase arises due to CP violation in the interference between $B_s^0$-$bar{B}_s^0$ mixing and the $b to s bar{s} s $ gluonic penguin decay amplitude. Using a sample of $pp$ collision data corresponding to an integrated luminosity of $1.0; fb^{-1}$ and collected at a centre-of-mass energy of $7 rm TeV$ with the LHCb detector, $880 B_s^0 to phiphi$ signal decays are obtained. The CP-violating phase is measured to be in the interval [-2.46, -0.76] rm rad$ at 68% confidence level. The p-value of the Standard Model prediction is 16%.
Using decays to $phi$-meson pairs, the inclusive production of charmonium states in $b$-hadron decays is studied with $pp$ collision data corresponding to an integrated luminosity of $3.0fb^{-1}$, collected by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. Denoting by $B_Cequiv B(bto CX)times B(Ctophiphi)$ the inclusive branching fraction of a $b$ hadron to a charmonium state $C$ that decays into a pair of $phi$ mesons, ratios $R^{C1}_{C2}equiv B_{C1}/B_{C2}$ are determined as $R^{chi_{c0}}_{eta_c(1S)}=0.147pm0.023pm0.011$, $R^{chi_{c1}}_{eta_c (1S)}=0.073pm0.016pm0.006$, $R^{chi_{c2}}_{eta_c (1S)}=0.081pm0.013pm0.005$, $R^{chi_{c1}}_{chi_{c0}}=0.50pm0.11pm0.01$, $R^{chi_{c2}}_{chi_{c0}}=0.56pm0.10pm0.01$ and $R^{eta_c (2S)}_{eta_c(1S)}=0.040pm0.011pm0.004$. Here and below the first uncertainties are statistical and the second systematic. Upper limits at $90%$ confidence level for the inclusive production of $X(3872)$, $X(3915)$ and $chi_{c2}(2P)$ states are obtained as $R^{X(3872)}_{chi_{c1}}<0.34$, $R^{X(3915)}_{chi_{c0}}<0.12$ and $R^{chi_{c2}(2P)}_{chi_{c2}}<0.16$. Differential cross-sections as a function of transverse momentum are measured for the $eta_c(1S)$ and $chi_c$ states. The branching fraction of the decay $B_s^0rightarrowphiphiphi$ is measured for the first time, $B(B_s^0tophiphiphi)=(2.15pm0.54pm0.28pm0.21_{B})times 10^{-6}$. Here the third uncertainty is due to the branching fraction of the decay $B_s^0tophiphi$, which is used for normalization. No evidence for intermediate resonances is seen. A preferentially transverse $phi$ polarization is observed. The measurements allow the determination of the ratio of the branching fractions for the $eta_c(1S)$ decays to $phiphi$ and $pbar{p}$ as $B(eta_c(1S)tophiphi)/B(eta_c(1S)to pbar{p})=1.79pm0.14pm0.32$.
The time-dependent CP asymmetry in B_s^0to J/psi K^+K^- decays is measured using $pp$ collision data at sqrt{s}=7TeV, corresponding to an integrated luminosity of 1.0fb^-1, collected with the LHCb detector. The decay time distribution is characterised by the decay widths Gamma_L and Gamma_H of the light and heavy mass eigenstates of the B_s^0--bar{B}_s^0 system and by a CP-violating phase phi_s. In a sample of 27,617 B_s^0to J/psi K^+K^- decays, where the dominant contribution comes from B_s^0to J/psiphi decays, these parameters are measured to be phi_s = 0.07 pm 0.09 (stat) pm 0.01 (syst) rad, Gamma_s equiv (Gamma_L+Gamma_H)/2 = 0.663 pm 0.005 (stat) pm 0.006 (syst) ps^-1, DeltaGamma_s equiv Gamma_L -Gamma_H = 0.100 pm 0.016 (stat) pm 0.003 (syst) & ps^-1, corresponding to the single most precise determination of phi_s, DeltaGamma_s and Gamma_s. The result of performing a combined analysis with B_s^{0} to J/psi pi^+pi^- decays gives phi_s = 0.01 pm 0.07 (stat) pm 0.01 (syst) rad, Gamma_s = 0.661 pm 0.004 (stat) pm 0.006 (syst) ps^-1, DeltaGamma_s = 0.106 pm 0.011 (stat) pm 0.007 (syst) & ps^-1. All measurements are in agreement with the Standard Model predictions.
A measurement of the decay time dependent CP-violating asymmetry in $B_s^0 to phiphi$ decays is presented, along with measurements of the $T$-odd triple-product asymmetries. In this decay channel, the CP-violating weak phase arises from the interference between $B_s^0$-$bar{B}_s^0$ mixing and the loop-induced decay amplitude. Using a sample of proton-proton collision data corresponding to an integrated luminosity of $3.0, fb^{-1}$ collected with the LHCb detector, a signal yield of approximately 4000 $B_s^0 to phiphi$ decays is obtained. The CP-violating phase is measured to be ${phi_s =-0.17pm0.15mathrm{,(stat)}pm0.03mathrm{,(syst)}}$ rad. The triple-product asymmetries are measured to be ${A_U=-0.003pm0.017mathrm{,(stat)}pm0.006mathrm{,(syst)}}$ and ${A_V=-0.017pm0.017mathrm{,(stat)}pm0.006mathrm{,(syst)}}$. Results are consistent with the hypothesis of CP conservation.
A flavour-tagged decay-time-dependent amplitude analysis of $B_s^0to(K^+pi^-)(K^-pi^+)$ decays is presented in the $K^{pm}pi^{mp}$ mass range from 750 to 1600 MeV$/c^2$. The analysis uses $pp$ collision data collected with the LHCb detector at centre-of-mass energies of $7$ and $8$ TeV, corresponding to an integrated luminosity of $3.0$ fb$^{-1}$. Several quasi-two-body decay modes are considered, corresponding to $K^{pm}pi^{mp}$ combinations with spin 0, 1 and 2, which are dominated by the $K_0^*(800)^0$ and $K_0^*(1430)^0$, the $K^*(892)^0$ and the $K_2^*(1430)^0$ resonances, respectively. The longitudinal polarisation fraction for the $B_s^0to K^*(892)^0overline{K}^*(892)^0$ decay is measured as $f_L=0.208 pm 0.032 pm 0.046$, where the first uncertainty is statistical and the second is systematic. The first measurement of the mixing-induced $CP$-violating phase, $phi_s^{doverline{d}}$, in $bto doverline{d}s$ transitions is performed, yielding a value of $phi_s^{doverline{d}}=-0.10$ $pm$ $0.13$ (stat) $pm$ $0.14$ (syst) rad.
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