Evaluating decay Rates and Asymmetries of $Lambda_b$ into Light Baryons in LFQM

In this work we calculate the branching ratios of semi-leptonic and non-leptonic decays of $Lambda_b$ into light baryons ($p$ and $Lambda$), as well as the measurable asymmetries which appear in the processes, in the light front quark model (LFQM). In the calculation, we adopt the diquark picture and discuss the justifiability of applying the picture in our case. Our result on the branching ratio of $Lambda_btoLambda+J/psi$ is in good agreement with data. More predictions are made in the same model and the results will be tested in the future experiments which will be conducted at LHCb and even ILC.

Interpretation of the $f_{D_s}$ puzzle in SM and beyond

The recent measurement on the decay constant of $D_s$ shows a discrepancy between theory and experiment. We study the leptonic and semileptonic decays of $D$ and $D_s$ simultaneously within the standard model by employing a lightfront quark model. There is space by tuning phenomenological parameters which can explain the $f_{D_s}$ puzzle and do not contradict other experiments on the semileptonic decays. We also investigate the leptonic decays of D and $D_{s}$ with a new physics scenario, unparticle physics. The unparticle effects induce a constructive interference with the standard model contribution. The nontrivial phase in unparticle physics could produce direct CP violation which may distinguish it from other new physics scenarios.