Probing new physics in semileptonic Σb and Ωb decays

Abstract

Recently, several hints of lepton nonuniversality have been observed in the semileptonic B meson decays in terms of both in the neutral current (b → sll) and charged current (b → clν l) transitions. Motivated by these inspiring results, we perform the analysis of the baryon decays Σ b → Σ c lν l and Ω b → Ω c lν l ðl ¼ e; μ; τÞ which are mediated by b → clν l transitions at the quark level, to scrutinize the nature of new physics (NP) in the model independent method. We first use the experimental measurements of BðB → D ðÃÞ lν l Þ, R D ðÃÞ and R J=ψ to constrain the NP coupling parameters in a variety of scenarios. Using the constrained NP coupling parameters, we report numerical results on various observables related to the processes Σ b → Σ c lν l and Ω b → Ω c lν l , such as the branching ratios, the ratio of branching fractions, the lepton side forward-backward asymmetries, the hadron and lepton longitudinal polarization asymmetries and the convexity parameter. We also provide the q 2 dependency of these observables and we hope that the corresponding numerical results in this work will be testified by future experiments.

Investigation of the effects of some new physics models in semileptonic Ξ b and Ω b decays

“…For Ω b → Ω c lν l decay, we only consider the effect of the aforementioned four NP models in this work. The SM central values of various observables for this process have been given in our previous work [79]. By comparing our results with those of [79], it is found that the P τ L of Ω b → Ω c τ ντ is positive, while all the P l L for the Ξ b → Ξ c lν l process are negative.…”

“…The SM central values of various observables for this process have been given in our previous work [79]. By comparing our results with those of [79], it is found that the P τ L of Ω b → Ω c τ ντ is positive, while all the P l L for the Ξ b → Ξ c lν l process are negative. Furthermore, all the P Ω c L are positive, while the P Ξ c L are negative.…”

“…R Ξ c is increasing with q 2 over the whole recoil region and R Ξ c → 0.65 when q 2 → q 2 max . After comparing the figure with figure 3 of [79], it is found that there are some similarities to a certain extent between P e(μ) L and C l F . Indeed, for the process Ω b → Ω c l νl the total differential decay rate for e mode is maximum at q 2 min and minimum at q 2 max .…”