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Register a new userMeasurement of form-factor independent observables in the decay $B^{0} to K^{*0} mu^+ mu^-$
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We present a measurement of form-factor independent angular observables in the decay mbox{$B^0to K^{*}(892)^{0}mu^+ mu^-$}. The analysis is based on a data sample corresponding to an integrated luminosity of 1.0fb$^{-1}$, collected by the LHCb experiment in $pp$ collisions at a center-of-mass energy of 7TeV. Four observables are measured in six bins of the dimuon invariant mass squared, $q^2$, in the range $0.1<q^2<19.0$GeV$^{2}$/c$^{4}$. Agreement with Standard Model predictions is found for 23 of the 24 measurements. A local discrepancy, corresponding to $3.7$ Gaussian standard deviations, is observed in one $q^2$ bin for one of the observables. Considering the 24 measurements as independent, the probability to observe such a discrepancy, or larger, in one is $0.5%$.
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We analyse the results recently presented on the $B^{+} to K^{*+} mu^+ mu^-$ angular observables by the LHCb Collaboration which show indications for New Physics beyond the Standard Model. Within a model-independent analysis, we compare the fit results with the corresponding results for the angular observables in $B^{0} to K^{*0} mu^+ mu^-$.
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.
The angular distribution and differential branching fraction of the decay $B^{0} to K^{*0} mu^{+}mu^{-}$ are studied using a data sample, collected by the LHCb experiment in $pp$ collisions at $sqrt{s}=7,{rm TeV}$, corresponding to an integrated luminosity of $1.0,{rm fb}^{-1}$. Several angular observables are measured in bins of the dimuon invariant mass squared, $q^{2}$. A first measurement of the zero-crossing point of the forward-backward asymmetry of the dimuon system is also presented. The zero-crossing point is measured to be $q_{0}^{2} = 4.9 pm 0.9 ,{rm GeV}^{2}/c^{4}$, where the uncertainty is the sum of statistical and systematic uncertainties. The results are consistent with the Standard Model predictions.
A search is presented for hidden-sector bosons, $chi$, produced in the decay ${B^0!to K^*(892)^0chi}$, with $K^*(892)^0!to K^{+}pi^{-}$ and $chi!tomu^+mu^-$. The search is performed using $pp$-collision data corresponding to 3.0 fb$^{-1}$ collected with the LHCb detector. No significant signal is observed in the accessible mass range $214 leq m({chi}) leq 4350$ MeV, and upper limits are placed on the branching fraction product $mathcal{B}(B^0!to K^*(892)^0chi)timesmathcal{B}(chi!tomu^+mu^-)$ as a function of the mass and lifetime of the $chi$ boson. These limits are of the order of $10^{-9}$ for $chi$ lifetimes less than 100 ps over most of the $m(chi)$ range, and place the most stringent constraints to date on many theories that predict the existence of additional low-mass bosons.
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