Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userRare B0_(s) -> mu+mu- decays
144
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
This review summarizes the current experimental results on rare B0_(s) -> mu+mu- decays of the Tevatron experiments CDF and D0, and the LHC experiments ATLAS, CMS and LHCb. The experimental branching fraction upper limits for the B0_s -> mu+mu- are already quite close to the branching fraction predicted by the Standard Model, and the first observation of the B0_s -> mu+mu- decay is expected soon. The rare decays B0_(s) -> mu+mu- are highly suppressed in the Standard Model, and therefore accurate measurements of these branching fractions provide complementary constraints to the free parameters of various extensions of the Standard Model.
rate research
Read More
oindent A search for the decays $B^0_{s}rightarrow mu^+ mu^- mu^+ mu^-$ and $B^0 rightarrow mu^+ mu^- mu^+ mu^-$ is performed using data, corresponding to an integrated luminosity of 1.0ensuremath{{,fb}^{-1}}xspace, collected with the LHCb detector in 2011. The number of candidates observed is consistent with the expected background and, assuming phase-space models of the decays, limits on the branching fractions are set: {${ensuremath{cal B}xspace}(B^0_{s}rightarrow mu^+ mu^- mu^+ mu^-) < 1.6 (1.2) times 10^{-8}$} and {${ensuremath{cal B}xspace}(B^0 rightarrow mu^+ mu^- mu^+ mu^-)< 6.6 (5.3) times 10^{-9}$} at 95,% (90,%) confidence level. In addition, limits are set in the context of a supersymmetric model which allows for the $B^0_{(s)}$ meson to decay into a scalar ($S$) and pseudoscalar particle ($P$), where $S$ and $P$ have masses of 2.5 GeV and 214.3 MeV, respectively, both resonances decay into $mu^+mu^-$. The branching fraction limits for these decays are {${ensuremath{cal B}xspace}(ensuremath{B^0_{s}rightarrow SP}xspace) < 1.6 (1.2) times 10^{-8}$} and {${ensuremath{cal B}xspace}(ensuremath{B^0rightarrow SP}xspace)< 6.3 (5.1) times 10^{-9}$} at 95% (90%) confidence level.
A search for the decays Bs -> mu+ mu- and B0 -> mu+ mu- is performed with 0.37 fb^-1 of pp collisions at sqrt{s} = 7 TeV collected by the LHCb experiment in 2011. The upper limits on the branching fractions are BR (Bs -> mu+ mu-) < 1.6 x 10^-8 and BR(B0 -> mu+ mu-) < 3.6 x 10^-9 at 95% confidence level. A combination of these results with the LHCb limits obtained with the 2010 dataset leads to BR (Bs -> mu+ mu-) < 1.4 x 10^-8 and BR (B0 -> mu+ mu-) < 3.2 x 10^-9 at 95% confidence level.
A search for Bs -> mu+ mu- and B0 -> mu+ mu- decays is performed using 1.0 fb^-1 of pp collision data collected at sqrt{s}=7 TeV with the LHCb experiment at the Large Hadron Collider. For both decays the number of observed events is consistent with expectation from background and Standard Model signal predictions. Upper limits on the branching fractions are determined to be BR(Bs -> mu+ mu-) < 4.5 (3.8) x 10^-9 and BR(B0 -> mu+ mu-) < 1.0 (0.81) x 10^-9 at 95% (90%) confidence level.
A search for non-resonant D+(s) to pi+mu+mu- and D+(s) to pi-mu+mu+ decays is performed using proton-proton collision data, corresponding to an integrated luminosity of 1.0 fb-1, at sqrt(s) = 7 TeV recorded by the LHCb experiment in 2011. No signals are observed and the 90% (95%) confidence level (CL) limits on the branching fractions are B(D+ to pi+mu+mu-) < 7.3 (8.3) x 10-8, B(Ds+ to pi+mu+mu-) < 4.1 (4.8) x 10-7, B(D+ to pi-mu+mu+) < 2.2 (2.5) x 10-8, B(Ds+ to pi-mu+mu+) < 1.2 (1.4) x 10-7. These limits are the most stringent to date.
First observations of the rare decays $B^+rightarrow K^+pi^+pi^-mu^+mu^-$ and $B^+rightarrow phi K^+mu^+mu^-$ are presented using data corresponding to an integrated luminosity of $3.0,{fb}^{-1}$, collected by the LHCb experiment at centre-of-mass energies of $7$ and $8mathrm{,TeV}$. The branching fractions of the decays are begin{eqnarray*} mathcal{B}(B^+rightarrow K^+pi^+pi^-mu^+mu^-) &=& (4.36,^{+0.29}_{-0.27},mathrm{(stat)}pm 0.21,mathrm{(syst)}pm0.18,mathrm{(norm)})times10^{-7}, mathcal{B}(B^+rightarrowphi K^+mu^+mu^-) &=& (0.82 ,^{+0.19}_{-0.17},mathrm{(stat)},^{+0.10}_{-0.04},mathrm{(syst)}pm0.27,mathrm{(norm)}) times10^{-7},end{eqnarray*} where the uncertainties are statistical, systematic, and due to the uncertainty on the branching fractions of the normalisation modes. A measurement of the differential branching fraction in bins of the invariant mass squared of the dimuon system is also presented for the decay $B^+rightarrow K^+pi^+pi^-mu^{+}mu^{-}$.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
