The differential branching fraction of the rare decay $Lambda^{0}_{b} rightarrow Lambda mu^+mu^-$ is measured as a function of $q^{2}$, the square of the dimuon invariant mass. The analysis is performed using proton-proton collision data, correspondi
ng to an integrated luminosity of $3.0 mbox{ fb}^{-1}$, collected by the LHCb experiment. Evidence of signal is observed in the $q^2$ region below the square of the $J/psi$ mass. Integrating over $15 < q^{2} < 20 mbox{ GeV}^2/c^4$ the branching fraction is measured as $dmathcal{B}(Lambda^{0}_{b} rightarrow Lambda mu^+mu^-)/dq^2 = (1.18 ^{+ 0.09} _{-0.08} pm 0.03 pm 0.27) times 10^{-7} ( mbox{GeV}^{2}/c^{4})^{-1}$, where the uncertainties are statistical, systematic and due to the normalisation mode, $Lambda^{0}_{b} rightarrow J/psi Lambda$, respectively. In the $q^2$ intervals where the signal is observed, angular distributions are studied and the forward-backward asymmetries in the dimuon ($A^{l}_{rm FB}$) and hadron ($A^{h}_{rm FB}$) systems are measured for the first time. In the range $15 < q^2 < 20 mbox{ GeV}^2/c^4$ they are found to be $A^{l}_{rm FB} = -0.05 pm 0.09 mbox{ (stat)} pm 0.03 mbox{ (syst)}$ and $A^{h}_{rm FB} = -0.29 pm 0.07 mbox{ (stat)} pm 0.03 mbox{ (syst)}$.
The differential branching fraction of the decay $Lambda_b^0rightarrowLambdamu^+mu^-$ is measured as a function of the square of the dimuon invariant mass, $q^2$. A yield of $78pm12$ $Lambda_b^0rightarrowLambdamu^+mu^-$ decays is observed using data,
corresponding to an integrated luminosity of 1.0,fb$^{-1}$, collected by the LHCb experiment at a centre-of-mass energy of 7,TeV. A significant signal is found in the $q^2$ region above the square of the $J/psi$ mass, while at lower-$q^2$ values upper limits are set on the differential branching fraction. Integrating the differential branching fraction over $q^2$, while excluding the $J/psi$ and $psi(2S)$ regions, gives a branching fraction of $BF($Lambda_b^0rightarrowLambdamu^+mu^-$)=(0.96pm 0.16statpm 0.13systpm 0.21 (mathrm{norm}))times 10^{-6}$, where the uncertainties are statistical, systematic and due to the normalisation mode, $$Lambda_b^0rightarrow J/psiLambda$, respectively.
The decays Bs0 --> Ds(*)+ Ds(*)- are reconstructed in a data sample corresponding to an integrated luminosity of 6.8 fb-1 collected by the CDF II detector at the Tevatron pbar{p} collider. All decay modes are observed with a significance of more than
10 sigma, and we measure the Bs0 production rate times Bs0 --> Ds(*)+ Ds(*)- branching ratios relative to the normalization mode B0 --> Ds+ D- to be $0.183 pm 0.021 pm 0.017$ for Bs0 --> Ds+ Ds-, $0.424 pm 0.046 pm 0.035$ for Bs0 --> Ds*+- Ds-+, $0.654 pm 0.072 pm 0.065$ for Bs0 --> Ds*+ Ds*-, and $1.261 pm 0.095 pm 0.112$ for the inclusive decay Bs0 --> Ds(*)+ Ds(*)-, where the uncertainties are statistical and systematic. These results are the most precise single measurements to date and provide important constraints for indirect searches for non-standard model physics in Bs0 mixing.
We briefly discuss measurements of CP violation in Bs --> J/psi phi decay. Both the phenomenology of Bs mixing and the importance of the measurement to searches for new physics, as well as technical details and issues with the analysis are included.
While current results are consistent with the standard model, even large contributions from new physics cannot be excluded.
We present improved bounds on the CP-violating phase beta_s^{Jpsiphi} and on the decay-width difference DeltaGamma of the neutral B_s^0 meson system obtained by the CDF experiment at the Tevatron collider . We use 6500 B_s^0 --> J/psi phi decays coll
ected by the dimuon trigger and reconstructed in a sample corresponding to integrated luminosity of 5.2 fb-1. Besides exploiting a two-fold increase in statistics with respect to the previous measurement, several improvements have been introduced in the analysis including a fully data-driven flavour-tagging calibration and proper treatment of possible S-wave contributions.
In past few years the flavor physics made important transition from the work on confirmation the standard model of particle physics to the phase of search for effects of a new physics beyond standard model. In this paper we review current state of th
e physics of b-hadrons with emphasis on results with a sensitivity to new physics.
Since 2003 several states in the charmonium mass region were discovered. While in the conventional c c-bar spectrum some states are missing, the number of states observed up to now is larger than empty spaces in the c c-bar spectrum. This, together w
ith other difficulties to explain observed states as a c c-bar mesons triggered discussions on a possible exotic interpretations. In this proceedings we present current experimental status from B-factories of the so called X, Y and Z states.
