Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userMeasurement of the isospin asymmetry in $B to K^{(*)}mu^+mu^-$ decays
110
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
The isospin asymmetries of $B to K^{(*)}mu^+mu^-$ decays and the partial branching fractions of $B^0 to K^0mu^+mu^-$ and $B^+ to K^{*+}mu^+mu^-$ are measured as a function of the di-muon mass squared $q^2$ using an integrated luminosity of 1.0 fb$^{-1}$ collected with the LHCb detector. The $B to Kmu^+mu^-$ isospin asymmetry integrated over $q^2$ is negative, deviating from zero with over 4 $sigma$ significance. The $B to K^{*}mu^+mu^-$ decay measurements are consistent with the Standard Model prediction of negligible isospin asymmetry. The observation of the decay $B^0 to K^0_{rmscriptscriptstyle S}mu^+mu^-$ is reported with 5.7 $sigma$ significance. Assuming that the branching fraction of $B^0 to K^0mu^+mu^-$ is twice that of $B^0 to K^0_{rmscriptscriptstyle S}mu^+mu^-$, the branching fractions of $B^0 to K^0mu^+mu^-$ and $B to K^{*+}mu^+mu^-$ are found to be ($0.31^{+0.07}_{-0.06}) times 10^{-6}$ and ($1.16pm0.19) times 10^{-6}$, respectively.
rate research
Read More
A measurement of the $CP$ asymmetry in $B^+ rightarrow K^+ mu^+ mu^-$ decays is presented using $pp$ collision data, corresponding to an integrated luminosity of 1.0${,fb}^{-1}$, recorded by the LHCb experiment during 2011 at a centre-of-mass energy of 7 TeV. The measurement is performed in seven bins of $mu^+ mu^-$ invariant mass squared in the range ${0.05<q^{2}<22.00{mathrm{GeV^2/}c^4}}$, excluding the ${J/psi}$ and $psi{(2S)}$ resonance regions. Production and detection asymmetries are corrected for using the $B^+ rightarrow J/psi K^+$ decay as a control mode. Averaged over all the bins, the $CP$ asymmetry is found to be ${{cal A}_{CP} = 0.000pm 0.033{(stat.)} pm0.005 {(syst.)} pm 0.007{}(J/psi K^+)}$, where the third uncertainty is due to the $CP$ asymmetry of the control mode. This is consistent with the Standard Model prediction.
The isospin asymmetries of $B to Kmu^+mu^-$ and $B to K^{*}mu^+mu^-$ decays and the partial branching fractions of the $B^0 to K^0mu^+mu^-$, $B^+ to K^+mu^+mu^-$ and $B^+ to K^{*+}mu^+mu^-$ decays are measured as functions of the dimuon mass squared, $q^2$. The data used correspond to an integrated luminosity of 3$~$fb$^{-1}$ from proton-proton collisions collected with the LHCb detector at centre-of-mass energies of 7$,$TeV and 8$,$TeV in 2011 and 2012, respectively. The isospin asymmetries are both consistent with the Standard Model expectations. The three measured branching fractions, while individually consistent, all favour lower values than their respective Standard Model predictions.
A measurement of the CP asymmetry in B0 -> K*0 mu+ mu- decays is presented, based on 1.0fb-1 of pp collision data recorded by the LHCb experiment during 2011. The measurement is performed in six bins of invariant mass squared of the mu+ mu- pair, excluding the J/psi and psi(2S) resonance regions. Production and detection asymmetries are removed using the B0 -> J/Psi K*0 decay as a control mode. The integrated CP asymmetry is found to be -0.072 +- 0.040 (stat.) +- 0.005 (syst.), consistent with the Standard Model.
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.
A search is performed for the lepton number violating decay $B^{+}to h^- mu^+ mu^+$, where $h^-$ represents a $K^-$ or a $pi^-$, using data from the LHCb detector corresponding to an integrated luminosity of $36pb^{-1}$. The decay is forbidden in the Standard Model but allowed in models with a Majorana neutrino. No signal is observed in either channel and limits of $B(B^{+} to K^- mu^+ mu^+) < 5.4times 10^{-8}$ and $B(B^{+} to pi^- mu^+ mu^+) < 5.8times 10^{-8}$ are set at the 95% confidence level. These improve the previous best limits by factors of 40 and 30, respectively.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
