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Anupama Bhol

Publications and source records attributed to Anupama Bhol.

5 recordsLinked to original sources
arXiv2021

$B_c \to D^{(*)}τ\bar ν_τ$ processes in an effective field theory approach

We present a compressive study on rare semileptonic $B_c \to D^{(*)}τ\bar ν_τ$ decays involving $b \to u τ\bar ν_τ$ quark level transitions in an effective field theory approach. We consider the presence of an additional (pseudo)vector and (pseudo)scalar type interactions which can be either complex or real and constrain the new couplings using the existing data on $R_{D^{(*)}}$, $R_{J/ψ}$, $R_π^l$, Br($B_{u,c} \to τ\bar ν_τ$) and Br($B \toπτ\bar ν_τ$) parameters. In order to segregate the sensitivity of new coefficients, we check the effects of these couplings on the branching ratios, lepton non-universality and various angular observables of $B_c \to D^{(*)}τ\bar ν_τ$ processes.

hep-ph↗
arXiv2020

Efficacy of scalar leptoquark on $B_s \to (K^{(*)}, D_s^{(*)}) τ\bar ν_τ$ decay modes

We scrutinize the impact of various relevant scalar leptoquarks on the physical observables associated with the rare semileptonic decay processes of $B_s$ meson involving $b \to (u, c) l\bar ν_l$ quark level transitions. We constrain the new parameter space consistent with the experimental limit on Br($B_{u,c} \to τν_l$), Br($B \to πτ\bar ν_τ$), $R_{D^{(*)}}, R_{J/ψ}$ and $R_π^l$ observables. Using the allowed parameter space, we compute the branching ratios, forward-backward asymmetries, lepton and hardon polarization asymmetries of $B_s \to (K^{(*)}, D_s^{(*)}) τ\bar ν_τ$ decay modes. Forbye, we look at the possibility of existence of lepton non-universality in these processes.

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arXiv2017

\large\bf $B_c \to (J/Ψ,\,η_c)τν$ semileptonic decays within Standard model and beyond

Deviations from the standard model prediction have been observed not only in $b \to c$ charged current interactions but also in $b \to s$ flavor changing neutral current interactions. In particular, the deviation observed in the measured ratio of branching fractions $R_D = \mathcal B(B \to Dτν)/\mathcal B(B \to D\,l\,ν)$ and $R_{D^{\ast}} =\mathcal B(B \to D^{\ast}τν)/\mathcal B(B \to D^{\ast}\,l\,ν)$, where $l = (e,\,μ)$, is more pronounced and the combined excess currently stands at $3.9σ$ level. If it persists and confirmed by future experiments, it would be a definite hint of new physics. In this context, we consider $B_c \to η_c\,l\,ν$ and $B_c \to J/Ψ\,l\,ν$ decays mediated via $b \to c\,l\,ν$ charged current interactions and employ the most general effective Lagrangian in the presence of new physics to give prediction on various observables such as ratio of branching ratio, tau polarization fraction, and forward backward asymmetry for these decay modes.

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arXiv2016

Model independent analysis of $b \to (c,\,u)\,τν$ leptonic and semileptonic decays

Latest measurement of the ratio of branching ratios $R_D = \mathcal B(B \to D\,τ\,ν)/\mathcal B(B \to D\,l\,ν)$ and $R_{D^{\ast}} = \mathcal B(B \to D^{\ast}\,τ\,ν)/\mathcal B(B \to D^{\ast}\,l\,ν)$, where $l$ is either an electron or muon, differs from the standard model expectation by $1.9σ$ and $3.3σ$, respectively. Similar tension has been observed in purely leptonic $B \to τν$ decays as well. In this context, we consider the most general effective Lagrangian in the presence of new physics and perform a model independent analysis to explore various new physics couplings. Motivated by the recently proposed new observables $R_D^τ = R_D/\mathcal B(B \to τν)$ and $R_{D^{\ast}}^τ = R_{D^{\ast}}/\mathcal B(B \to τν)$, we impose $2σ$ constraints coming from $R_D^τ$ and $R_{D^{\ast}}^τ$ in addition to the constraints coming from $R_D$, $R_{D^{\ast}}$, and $\mathcal B(B \to τν)$ to constrain the new physics parameter space. We study the impact of new physics on various observables related to $B_s \to (D_s,\,D^{\ast}_s)τν$ and $B \to πτν$ decay processes.

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arXiv2013

Effective theory approach to new physics in $b \to u$ and $b \to c$ leptonic and semileptonic decays

Recent measurements of exclusive $B^{-} \to τ^{-}\,ν$ and $B^0 \to π^{+}\,l^{-}\,\barν_l$ decays via the $b \to u\,l\,ν$ transition process differ from the standard model expectation and, if they persist in future $B$ experiments, will be a definite hint of the physics beyond the standard model. Similar hints of new physics have been observed in $b \to c$ semileptonic transition processes as well. BABAR measures the ratio of branching fractions of $B \to (D,\,D^{\ast})\,τ\,ν$ to the corresponding $B \to (D,\,D^{\ast})\,lν$, where $l$ represents either an electron or a muon, and finds $3.4σ$ discrepancy with the standard model expectation. In this context, we consider a most general effective Lagrangian for the $b \to u\,l\,ν$ and $b \to c\,l\,ν$ transition processes in the presence of new physics and perform a combined analysis of all the $b \to u$ and $b \to c$ semi-(leptonic) data to explore various new physics operators and their couplings. We consider various new physics scenarios and give predictions for the $B_c \to τν$ and $B \to πτν$ decay branching fractions. We also study the effect of these new physics parameters on the ratio of the branching ratios of $B \to πτν$ to the corresponding $B \to π\,l\,ν$ decays.

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