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Register a new userMeasurement of the $K^+rightarrow{mu^+}{ u_{mu}}{gamma}$ decay form factors in the OKA experiment
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A precise measurement of the vector and axial-vector form factors difference $F_V-F_A$ in the $K^+rightarrow{mu^+}{ u_{mu}}{gamma}$ decay is presented. About 95K events of $K^+rightarrow{mu^+}{ u_{mu}}{gamma}$ are selected in the OKA experiment. The result is $F_V-F_A=0.134pm0.021(stat)pm0.027(syst)$. Both errors are smaller than in the previous $F_V-F_A$ measurements.
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By analyzing 2.93 fb$^{-1}$ of data collected at $sqrt s=3.773$ GeV with the BESIII detector, we measure the absolute branching fraction ${mathcal B}(D^{+}rightarrowbar K^0mu^{+} u_{mu})=(8.72 pm 0.07_{rm stat.} pm 0.18_{rm sys.})%$, which is consistent with previous measurements within uncertainties but with significantly improved precision. Combining the Particle Data Group values of ${mathcal B}(D^0to K^-mu^+ u_mu)$, ${mathcal B}(D^{+}rightarrowbar K^0 e^{+} u_{e})$, and the lifetimes of the $D^0$ and $D^+$ mesons with the value of ${mathcal B}(D^{+}rightarrowbar K^0 mu^{+} u_{mu})$ measured in this work, we determine the following ratios of partial widths: $Gamma(D^0to K^-mu^+ u_mu)/Gamma(D^{+}rightarrowbar K^0mu^{+} u_{mu})=0.963pm0.044$ and $Gamma(D^{+}rightarrowbar K^0 mu^{+} u_{mu})/Gamma(D^{+}rightarrowbar K^0 e^{+} u_{e})=0.988pm0.033$.
We report the first measurement of the absolute branching fraction for $Lambda^+_{c}rightarrow Lambda mu^+ u_{mu}$. This measurement is based on a sample of $e^+e^-$ annihilation data at a center-of-mass energy of $sqrt{s}=4.6$ GeV collected with the BESIII detector at the BEPCII storage rings. The sample corresponds to an integrated luminosity of 567 pb$^{-1}$. The branching fraction is determined to be $mathcal B({Lambda^+_crightarrow Lambda mu^+ u_{mu}})=(3.49pm0.46({rm stat})pm0.27({rm syst}))%$. In addition, we calculate the ratio $mathcal{B}(Lambda^+_crightarrow Lambda mu^+ u_{mu})/mathcal{B}(Lambda^+_crightarrow Lambda e^+ u_{e})$ to be $0.96pm0.16({rm stat})pm0.04({rm syst})$.
The direct $C!P$ asymmetries of the decays $B^0 rightarrow K^{*0} mu^+ mu^-$ and $B^+ rightarrow K^{+} mu^+ mu^-$ are measured using $pp$ collision data corresponding to an integrated luminosity of 3.0$mbox{fb}^{-1}$ collected with the LHCb detector. The respective control modes $B^0 rightarrow J/psi K^{*0}$ and $B^+ rightarrow J/psi K^{+}$ are used to account for detection and production asymmetries. The measurements are made in several intervals of $mu^+ mu^-$ invariant mass squared, with the $phi(1020)$ and charmonium resonance regions excluded. Under the hypothesis of zero $C!P$ asymmetry in the control modes, the average values of the asymmetries are begin{align} {cal A}_{C!P}(B^0 rightarrow K^{*0} mu^+ mu^-) &= -0.035 pm 0.024 pm 0.003, cr {cal A}_{C!P}(B^+ rightarrow K^{+} mu^+ mu^-) &= phantom{-}0.012 pm 0.017 pm 0.001, end{align} where the first uncertainties are statistical and the second are due to systematic effects. Both measurements are consistent with the Standard Model prediction of small $C!P$ asymmetry in these decays.
We present an angular analysis of the $B^{+}rightarrow K^{ast+}(rightarrow K_{S}^{0}pi^{+})mu^{+}mu^{-}$ decay using 9$,mbox{fb}^{-1}$ of $pp$ collision data collected with the LHCb experiment. For the first time, the full set of CP-averaged angular observables is measured in intervals of the dimuon invariant mass squared. Local deviations from Standard Model predictions are observed, similar to those in previous LHCb analyses of the isospin-partner $B^{0}rightarrow K^{ast0}mu^{+}mu^{-}$ decay. The global tension is dependent on which effective couplings are considered and on the choice of theory nuisance parameters.
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