Related papers: Fourth generation effect on $\Lambda_b$ decays
CP-violating effects in decays of B mesons offer a wide spectrum of probes for testing the phase structure of the quark-flavour sector of the Standard Model. After a brief discussion of the picture emerging from the current LHC data, the…
The vector-like quark model is one of the extensions of the standard model (SM) of particle physics. The simplest version of this model introduces a vector-like singlet quark which can mix with SM quarks and give rise to new contributions…
These lectures present the phenomenology of B meson decays and their impact on our understanding of CP violation in the quark sector, with an emphasis on measurements made at the e+e- B factories. Some of the relevant theoretical ideas such…
We investigate the rare decay $\Lambda_b \to \Lambda \gamma$ which receives both short and long distance contributions. We estimate the long distance contributions and find them very small. The form factors are obtained from $\Lambda_c \to…
Purely baryonic weak decays of heavy baryons are investigated within the framework of the Skyrme model. These decays belong to a new class of unobserved decay channels, which would help us to test the standard model, particularly potential…
The semileptonic transition of $\Lambda_b$ baryon is studied using the Hypercentral constituent quark model. The six-dimensional hyperradial $Schr\ddot{o}dinger$ equation is solved in the variational approach to get masses and wavefunctions…
We analyze in the four-generation model the first measurement of the branching ratio of rare kaon decay $K^+\to\pi^+\nu\bar{nu}$, along with the other processes of $K_L-K_S$ mass difference $\Delta m_K$, CP-violating parameter $\epsilon_K,…
If the Higgs-like particle at 126 GeV is the standard model Higgs boson, then SM4, the simplest four generation extension of the SM, is inconsistent with the most recent LHC data. However, 4G variations (BSM4) are possible if the new…
Within the Standard Model, we investigate the weak decays of $\Lambda_b \to \Lambda + \gamma$ and $\Lambda_b \to \Lambda + l^{+} l^{-}$ with the light-cone sum rules approach. The higher twist distribution amplitudes of $\Lambda$ baryon to…
We give a description of why the existence of a fourth generation is likely to provide enough CP violation for baryogenesis, and trace how this observation came about. We survey the current experimental and theoretical pursuits and outline…
Stimulated by the newly observed $\Lambda_b(6146)^0$ and $\Lambda_b(6152)^0$ resonances, we investigate the strong decays of the low-lying singly bottom baryons within the quark pair creation model. Considering their masses and decay modes,…
The polarization of $\Lambda_b$ baryon has been measured in ALEPH, OPAL and DELPHI experiments. A significant loss on the transfer of the $b$ quark polarization to the $\Lambda_b$ baryon polarization has been noticed. This implies that the…
We conduct a systematic study of the impact of new physics in quark-level $b \to c \bar{c} s$ transitions on $B$-physics, in particular rare $B$-decays and $B$-meson lifetime observables. We find viable scenarios where a sizable effect in…
We study the decays of heavy chiral (t', b') quarks in a four-generation extension of the Standard Model. If the difference between the t' and b' masses is smaller than the W mass, as favored by precision electroweak measurements, then the…
The search for the effects of heavy fermions in the extension of the Standard Model with a fourth generation is part of the experimental program of the Tevatron and LHC experiments. Besides being directly produced, these states affect…
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 study the rare decays of B meson. We want to constraint the NSIs by using these reactions. We show that there is a strong dependence of these reactions on new physics parameter. We include second and third generation of quarks in the…
We study the scalar leptoquark effects on the rare semileptonic decays of $\Lambda_b$ baryon, governed by the quark level transition $b \to s l^+ l^-$. We estimate the branching ratios, forward-backward asymmetries, lepton polarization…
Recent rate measurements of B_s mesons and Lambda_b baryons produced in sqrt{s} = 1.96 TeV proton-antiproton and Upsilon(5S) electron-positron collisions are reviewed, including the first observations of six new decay modes: B_s -> D_s^+…
Within the framework of perturbative QCD approach based on $k_T$ factorization, we studied 40 $B_c \to DS$ decay modes in the leading order and leading power, where "S" stands for the light scalar meson. Under two different scenarios (S1…