相关论文: Hints for a Low Bs --> mu+ mu- Rate and the Fourth…
We show that simultaneous precision measurement of the CP-violating phase in time-dependent Bs --> J/psi phi study and the Bs --> mu+ mu- rate, together with measuring m_t' by direct search at the LHC, would determine V_{t's}^*V_{t'b} and…
The weak decays of B_{c} --> D_{s}^{*}l^{+}l^{-} (l=mu,tau) are investigated in the Standard Model with fourth generation (SM4). Taking fourth generation quark mass m_{t'} of about 300 to 600 GeV with the CKM matrix elements…
We estimate the CP asymmetry A_{CP}(q^2) in the decays B --> X_s mu+ mu- and B --> X_d mu+ mu- in the standard model (SM) with an additional fourth generation. We use a parametrization that allows us to explore the complete parameter space…
The long-awaited $B_s\to \mu^+\mu^-$ mode has finally been observed at rate consistent with Standard Model, albeit lower by 1.2$\sigma$. There is some hint for New Physics in the rarer $B_d^0 \to \mu^+\mu^-$ decay, especially if the…
We investigate the recent CDF measurement of the Br(B_s --> mu+mu-) which shows excess over the Standard Model. We consider minimal supergravity motivated models (mSUGRA)/CMSSM and grand unified models, SU(5) and SO(10). In the grand…
We study D0-D0 mixing in the presence of a fourth generation of quarks. In particular, we calculate the size of the allowed CP violation which is found at the observable level well beyond anything possible with CKM dynamics. We calculate…
The very rare Bd0 --> mu+ mu- decay may be the last chance for New Physics in flavor sector at the LHC, before the 13 TeV run in 2015. Partially motivated by the known tension in sin(2beta/phi_1), enhancement beyond (3-4) x 10^-10 would…
Combining the measured B_s mixing with b \to s\ell^+\ell^- rate data, we find a sizable 4 generation t' quark effect is allowed, for example with m_{t'} \sim 300 GeV and V_{t's}^*V_{t'b} \sim 0.025 e^{\pm i 70^\circ}, which could underly…
The rare decays B_s -> \mu^+\mu^- and B -> K^{(*)}\mu^+\mu^- are sensitive to new particles and couplings via their interferences with the standard model contributions. Recently, the upper bound on B(B_s -> \mu^+\mu^-) has been improved…
We summarise the analyses that search for fourth generation quarks at the Central Muon Solenoid (CMS) experiment. Such particles provide a natural extension to the Standard Model (SM) and are still consistent with precision electroweak…
We investigate the influence of the fourth generation quarks on the branching ratio and the CP-asymmetry in B -->\pi \ell^+ \ell^- decay. Taking the |V_{t'd}V_{t'b}| ~ 0.001 with phase about 10 degree, which is consistent with the…
We extend our recent work and study implications of the Standard Model with four generations (SM4) for rare B and K decays. We again take seriously the several 2-3 $\sigma$ anomalies seen in B, $B_s$ decays and interpret them in the context…
A 4th generation could be consistent with the recently measured $\Delta m_{B_s}$ as well as ${\cal B}(b\to s\ell^+\ell^-)$, which are SM-like, but generate large $\sin2\Phi_{B_s} \simeq -0.5$ to -0.7. The sign is determined by the hint for…
The non-minimal flavour violating interactions of mirror quarks and new heavy gauge bosons in the Littlest Higgs model with T-parity (LHT) give rise to naturally large CP-violating effects in the B_s system. In view of a large new CP phase…
A search for the rare decays Bs->mu+mu- and B0->mu+mu- is performed using data collected in 2011 and 2012 with the LHCb experiment at the Large Hadron Collider. The data samples comprise 1.1 fb^-1 of proton-proton collisions at sqrt{s} = 8…
We calculate a number of observables related to particle-antiparticle mixing and the branching ratios for the most interesting rare and CP-violating K and B decays in the Standard Model (SM3) extended by a fourth generation of quarks and…
We investigate the influence of the fourth generation of quarks on the branching ratio, the CP-asymmetry and the polarization asymmetries in $B \rar \rho \ell^+ \ell^-$ decay. Taking $|V_{t'd}V_{t'b}|\sim 0.001$ with phase about $10^\circ$,…
A search for the rare decays B_s to mu+ mu- and B^0 to mu^+ mu^- is performed in pp collisions at sqrt(s) = 7 TeV, with a data sample corresponding to an integrated luminosity of 5 inverse femtobarns collected by the CMS experiment at the…
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…
Recently two hints for new physics have emerged: The B_s mixing phase phi_s and the rate of D_s -> (mu,tau) nu exposing a discrepancy of \sim 3 sigma and 3.8 sigma deviation from the Standard Model respectively. Moreover the difference of…