Aishwarya Bhatta
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Research Subjects
Research Interests
Aishwarya Bhatta has a total of 10 co-authors. Here are the top co-authors by number of shared publications:
- Rukmani Mohanta
University of Hyderabad
9 shared publications - Atasi Ray
School of Physics, University of Hyderabad, Hyderabad 500046, India
2 shared publications - Purushottam Sahu
Indian Institute of Technology Bombay
2 shared publications Rukmani Mohanta
University of Hyderabad
2 shared publications- Shivaramakrishna Singirala
University of Hyderabad
2 shared publications - Sudhanwa Patra
Indian Institute of Technology Bhilai
2 shared publications
Latest Publications
- Open Access
- 3 October 2025
- Published by American Physical Society (APS) in Physical Review D
- Vol. 112 (7)
Unraveling new physics effects in transitions with a model-independent perspectiveMotivated by recent anomalies in observables associated with flavor-changing neutral current transitions, specifically b → s ℓ + ℓ − processes, we present a comprehensive analysis of lepton flavor-violating (LFV) decay modes mediated by b → s ℓ 1 ℓ 2 transitions with ℓ 1 ≠ ℓ 2 . While such LFV processes are forbidden within the standard model, they naturally arise in several of its extensions, including models featuring additional vectorlike fermions and extra Z ′ bosons. Employing the most general effective Hamiltonian for b → s ℓ 1 ℓ 2 transitions, we derive the angular distributions of the relevant decay modes. Adopting a model-independent framework, we systematically study the LFV decays B → K * ℓ 1 ℓ 2 , B s → ϕ ℓ 1 ℓ 2 , B → K 2 * ℓ 1 ℓ 2 , and Λ b → Λ ℓ 1 ℓ 2 . Although LFV mesonic decays have been widely explored, the corresponding baryonic decays remain comparatively underinvestigated. We provide bounds on the branching ratio ( B ), forward-backward asymmetry ( A F B ), and longitudinal lepton polarization fraction ( F L ). Furthermore, considering the projected sensitivities of the LHCb upgrade and Belle II experiments, we estimate upper limits for these observables, offering promising avenues for probing new physics in these LFV channels.
- 3 October 2025
- Published by American Physical Society (APS) in Physical Review D
- Vol. 112 (7)
Open AccessUnraveling new physics effects in transitions with a model-independent perspectiveMotivated by recent anomalies in observables associated with flavor-changing neutral current transitions, specifically b → s ℓ + ℓ − processes, we present a comprehensive analysis of lepton flavor-violating (LFV) decay modes mediated by b → s ℓ 1 ℓ 2 transitions with ℓ 1 ≠ ℓ 2 . While such LFV processes are forbidden within the standard model, they naturally arise in several of its extensions, including models featuring additional vectorlike fermions and extra Z ′ bosons. Employing the most general effective Hamiltonian for b → s ℓ 1 ℓ 2 transitions, we derive the angular distributions of the relevant decay modes. Adopting a model-independent framework, we systematically study the LFV decays B → K * ℓ 1 ℓ 2 , B s → ϕ ℓ 1 ℓ 2 , B → K 2 * ℓ 1 ℓ 2 , and Λ b → Λ ℓ 1 ℓ 2 . Although LFV mesonic decays have been widely explored, the corresponding baryonic decays remain comparatively underinvestigated. We provide bounds on the branching ratio ( B ), forward-backward asymmetry ( A F B ), and longitudinal lepton polarization fraction ( F L ). Furthermore, considering the projected sensitivities of the LHCb upgrade and Belle II experiments, we estimate upper limits for these observables, offering promising avenues for probing new physics in these LFV channels.
- Open Access
- 14 July 2025
- Published by Stichting SciPost in SciPost Physics Proceedings
- No. 16,p. 012
Implications of new physics in $\Lambda_b \to \Lambda_c \ell \nu_{\ell}$ decay processesSeveral indications of lepton non universality ratios, R{(D^*)} R ( D * ) , R{(J/\Psi)} R ( J / Ψ ) and the measurements on hadronic and \tau τ longitudinal polarizations in b \to c \ell \bar{\nu_{\tau}} b → c ℓ ν τ ‾ processes have attracted a lot of attentions. By considering the most general effective Lagrangian, we carry out a model independent analysis of the semileptonic \Lambda_b Λ b decays, to inspect the nature of new physics. We constraint the new physics parameter space by using the chi square fitting. We study the implications of constrained new couplings on the observable such as branching fractions, forward-backward asymmetries, lepton non universality parameter and \Lambda_c Λ c and lepton longitudinal polarization fractions of the decay modes.
- 14 July 2025
- Published by Stichting SciPost in SciPost Physics Proceedings
- No. 16,p. 012
Open AccessImplications of new physics in $\Lambda_b \to \Lambda_c \ell \nu_{\ell}$ decay processesSeveral indications of lepton non universality ratios, R{(D^*)} R ( D * ) , R{(J/\Psi)} R ( J / Ψ ) and the measurements on hadronic and \tau τ longitudinal polarizations in b \to c \ell \bar{\nu_{\tau}} b → c ℓ ν τ ‾ processes have attracted a lot of attentions. By considering the most general effective Lagrangian, we carry out a model independent analysis of the semileptonic \Lambda_b Λ b decays, to inspect the nature of new physics. We constraint the new physics parameter space by using the chi square fitting. We study the implications of constrained new couplings on the observable such as branching fractions, forward-backward asymmetries, lepton non universality parameter and \Lambda_c Λ c and lepton longitudinal polarization fractions of the decay modes.
- 17 July 2024
- Published by Springer Nature
- p. 102-106
Implications of New Physics in Semileptonic $b \rightarrow c \tau \bar{\nu }$ Transitions- 17 July 2024
- Published by Springer Nature
- p. 102-106
Implications of New Physics in Semileptonic $b \rightarrow c \tau \bar{\nu }$ Transitions- 10 October 2023
- Published by World Scientific Pub Co Pte Ltd in International Journal of Modern Physics A
- Vol. 38 (28)
Delving into new physics in semileptonic b→cτν̄ transitions
In recent times, there have been several observations suggesting deviations from lepton universality in semileptonic decays of [ ] mesons. These deviations have been noticed both in the neutral-current transitions ([ ]) and charged-current transitions ([ ]). Motivated by these intriguing findings, we investigate the semileptonic decays involving the quark-level transitions of [ ]. To explore the presence of new physics, we adopt a model-independent approach and analyze the processes [ ], [ ] and [ ], where [ ] represent the four lightest excited charm mesons. Considering a comprehensive effective Hamiltonian, we perform a global fit using various sets of new coefficients and incorporate measurements of [ ], [ ], [ ], [ ], as well as the upper limit on the branching ratio of [ ]. Subsequently, we examine the impact of constrained new couplings on the branching ratios, forward–backward asymmetry parameters, lepton nonuniversality (LNU) ratios, as well as lepton and hadron polarization asymmetries in these decay modes.
- 10 October 2023
- Published by World Scientific Pub Co Pte Ltd in International Journal of Modern Physics A
- Vol. 38 (28)
Delving into new physics in semileptonic b→cτν̄ transitions
In recent times, there have been several observations suggesting deviations from lepton universality in semileptonic decays of [ ] mesons. These deviations have been noticed both in the neutral-current transitions ([ ]) and charged-current transitions ([ ]). Motivated by these intriguing findings, we investigate the semileptonic decays involving the quark-level transitions of [ ]. To explore the presence of new physics, we adopt a model-independent approach and analyze the processes [ ], [ ] and [ ], where [ ] represent the four lightest excited charm mesons. Considering a comprehensive effective Hamiltonian, we perform a global fit using various sets of new coefficients and incorporate measurements of [ ], [ ], [ ], [ ], as well as the upper limit on the branching ratio of [ ]. Subsequently, we examine the impact of constrained new couplings on the branching ratios, forward–backward asymmetry parameters, lepton nonuniversality (LNU) ratios, as well as lepton and hadron polarization asymmetries in these decay modes.
- Open AccessDelving into new physics in semileptonic $b \to c τ\bar ν$ transitionsRecently, several indications of lepton non-universality observables have been perceived in semileptonic $B$ meson decay processes, both in the neutral-current ($b \to s ll $) and charged-current ($b \to c l \bar \nu_l$) transitions. Influenced by these fascinating quotients, we examine the semileptonic decays involving the $b \to c l \bar \nu_l$ quark level transitions. We execute it through a model independent analysis in order to probe the nature of new physics. Taking into consideration the most general effective Hamiltonian, we scrutinize $\Lambda_b \to \Lambda_c \tau \bar \nu_\tau$, $ B_c^+ \to \eta_c \tau^+ \nu_\tau$, and $ B \to D^{**} \tau \bar \nu_\tau$ (where $D^{**} = \{D^*_0, D_1^*, D_1, D_2^*\}$ are the four lightest excited charm mesons) processes, in the presence of new physics. We perform a global fit to different sets of new coefficients, making use of the measurements on $R_{D}$, $R_{D^{*}}$, $R_{J/\psi}$, $P_{\tau}^{D^*}$ and the upper limit on Br($B_c^+ \to \tau^+ \nu_\tau$). We then inspect the effect of constrained new couplings on the branching ratios, forward-backward asymmetry parameters, lepton non-universality ratios (LNU), lepton and hadron polarization asymmetries of these decay modes.Open AccessDelving into new physics in semileptonic $b \to c τ\bar ν$ transitionsRecently, several indications of lepton non-universality observables have been perceived in semileptonic $B$ meson decay processes, both in the neutral-current ($b \to s ll $) and charged-current ($b \to c l \bar \nu_l$) transitions. Influenced by these fascinating quotients, we examine the semileptonic decays involving the $b \to c l \bar \nu_l$ quark level transitions. We execute it through a model independent analysis in order to probe the nature of new physics. Taking into consideration the most general effective Hamiltonian, we scrutinize $\Lambda_b \to \Lambda_c \tau \bar \nu_\tau$, $ B_c^+ \to \eta_c \tau^+ \nu_\tau$, and $ B \to D^{**} \tau \bar \nu_\tau$ (where $D^{**} = \{D^*_0, D_1^*, D_1, D_2^*\}$ are the four lightest excited charm mesons) processes, in the presence of new physics. We perform a global fit to different sets of new coefficients, making use of the measurements on $R_{D}$, $R_{D^{*}}$, $R_{J/\psi}$, $P_{\tau}^{D^*}$ and the upper limit on Br($B_c^+ \to \tau^+ \nu_\tau$). We then inspect the effect of constrained new couplings on the branching ratios, forward-backward asymmetry parameters, lepton non-universality ratios (LNU), lepton and hadron polarization asymmetries of these decay modes.
- Open AccessInvestigating $ Υ(ns) \to τ^+ τ^- $ decay in the Leptoquark scenarioSeveral measurements on $R_D, R_{D^*}$, and $R_{J/ \psi}$ by the BaBar, Belle, and LHCb experiments show significant deviations from their Standard Model (SM) predictions, which illustrate the fact that the concept of lepton flavor universality (LFU) is violated in semileptonic $B$ meson as well as leptonic $\Upsilon(ns)(n=1,2,3)$ decays. Recently BaBar experiment announced that at $1.8\sigma$ level, $R_\Upsilon(3s)= {\rm Br}(\Upsilon(3s) \to \tau \bar{\tau})/{\rm Br}(\Upsilon(3s) \to \mu \bar{\mu})$ shows an acceptance with the SM. These fascinating findings point towards the possible implication of new physics in the $b \to c \tau \bar{\nu}$ transitions, which in turn, creates a new direction to look for new physics in $b \bar{b} \to \tau \bar{\tau} $ process. Thereby, the new physics contributions to the $b \to c \tau \bar{\nu}$ process would inevitably alter the $b \bar{b} \to \tau \bar{\tau} $ transitions. Here we conduct a $\chi^{2}$ fit to constraining the new parameters by using the measured values of $ R_D$, $R{_D*}$, $ R_{J/ \psi}$, $ R_{X_C}$, $F_L (D^*)$ and $P_{\tau} (D^*)$. In this context, we investigate the effect of constrained new physics couplings on the branching ratios and LFU parameters $R_{\Upsilon(ns)}$ through leptoquark models such as $S_3, \tilde{S_1}, \tilde{R_2}, U_1, U_3 $ and $ V_2$.Open AccessInvestigating $ Υ(ns) \to τ^+ τ^- $ decay in the Leptoquark scenarioSeveral measurements on $R_D, R_{D^*}$, and $R_{J/ \psi}$ by the BaBar, Belle, and LHCb experiments show significant deviations from their Standard Model (SM) predictions, which illustrate the fact that the concept of lepton flavor universality (LFU) is violated in semileptonic $B$ meson as well as leptonic $\Upsilon(ns)(n=1,2,3)$ decays. Recently BaBar experiment announced that at $1.8\sigma$ level, $R_\Upsilon(3s)= {\rm Br}(\Upsilon(3s) \to \tau \bar{\tau})/{\rm Br}(\Upsilon(3s) \to \mu \bar{\mu})$ shows an acceptance with the SM. These fascinating findings point towards the possible implication of new physics in the $b \to c \tau \bar{\nu}$ transitions, which in turn, creates a new direction to look for new physics in $b \bar{b} \to \tau \bar{\tau} $ process. Thereby, the new physics contributions to the $b \to c \tau \bar{\nu}$ process would inevitably alter the $b \bar{b} \to \tau \bar{\tau} $ transitions. Here we conduct a $\chi^{2}$ fit to constraining the new parameters by using the measured values of $ R_D$, $R{_D*}$, $ R_{J/ \psi}$, $ R_{X_C}$, $F_L (D^*)$ and $P_{\tau} (D^*)$. In this context, we investigate the effect of constrained new physics couplings on the branching ratios and LFU parameters $R_{\Upsilon(ns)}$ through leptoquark models such as $S_3, \tilde{S_1}, \tilde{R_2}, U_1, U_3 $ and $ V_2$.
- Open Access
- 7 November 2022
- Published by Springer Nature in Journal of High Energy Physics
- Vol. 2022 (11) , 1-40
Flavour anomalies and dark matter assisted unification in SO(10) GUT
With the recent experimental hint of new physics from flavor physics anomalies, combined with the evidence from neutrino masses and dark matter, we consider a minimal extension of SM with a scalar leptoquark and a fermion triplet. The scalar leptoquark with couplings to leptons and quarks can explain lepton flavor non-universality observables RK, $$ {R}_{K^{\left(\ast \right)}} $$ , $$ {R}_{D^{\left(\ast \right)}} $$ and RJ/ψ. Neutral component of fermion triplet provides current abundance of dark matter in the Universe. The interesting feature of the proposal is that the minimal addition of these phenomenologically rich particles (scalar leptoquark and fermion triplet) assist in realizing the unification of the gauge couplings associated with the strong and electroweak forces of standard model when embedded in the non-supersymmetric SO(10) grand unified theory. We discuss on unification mass scale and the corresponding proton decay constraints while taking into account the GUT threshold corrections.- 7 November 2022
- Published by Springer Nature in Journal of High Energy Physics
- Vol. 2022 (11) , 1-40
Open AccessFlavour anomalies and dark matter assisted unification in SO(10) GUT
With the recent experimental hint of new physics from flavor physics anomalies, combined with the evidence from neutrino masses and dark matter, we consider a minimal extension of SM with a scalar leptoquark and a fermion triplet. The scalar leptoquark with couplings to leptons and quarks can explain lepton flavor non-universality observables RK, $$ {R}_{K^{\left(\ast \right)}} $$ , $$ {R}_{D^{\left(\ast \right)}} $$ and RJ/ψ. Neutral component of fermion triplet provides current abundance of dark matter in the Universe. The interesting feature of the proposal is that the minimal addition of these phenomenologically rich particles (scalar leptoquark and fermion triplet) assist in realizing the unification of the gauge couplings associated with the strong and electroweak forces of standard model when embedded in the non-supersymmetric SO(10) grand unified theory. We discuss on unification mass scale and the corresponding proton decay constraints while taking into account the GUT threshold corrections. - Open AccessFlavour anomalies and dark matter assisted unification in $SO(10)$ GUTWith the recent experimental hint of new physics from flavor physics anomalies, combined with the evidence from neutrino mass and dark matter, we consider a minimal extension of SM with a scalar leptoquark and a fermion triplet. The scalar leptoquark with couplings to leptons and quarks can explain lepton flavor non-universality observables $R_K$, $R_{K^{(*)}}$, $R_{D^{(*)}}$ and $R_{J/\psi}$. Neutral component of fermion triplet provides current abundance of dark matter in the Universe. The interesting feature of the proposal is that the minimal addition of these phenomenologically rich particles (scalar leptoquark and fermion triplet) assist in realizing the unification of the gauge couplings associated with the strong and electroweak forces of standard model when embedded in the non-supersymmetric $SO(10)$ grand unified theory. We discuss on unification mass scale and the corresponding proton decay constraints while taking into account the GUT threshold corrections.Open AccessFlavour anomalies and dark matter assisted unification in $SO(10)$ GUTWith the recent experimental hint of new physics from flavor physics anomalies, combined with the evidence from neutrino mass and dark matter, we consider a minimal extension of SM with a scalar leptoquark and a fermion triplet. The scalar leptoquark with couplings to leptons and quarks can explain lepton flavor non-universality observables $R_K$, $R_{K^{(*)}}$, $R_{D^{(*)}}$ and $R_{J/\psi}$. Neutral component of fermion triplet provides current abundance of dark matter in the Universe. The interesting feature of the proposal is that the minimal addition of these phenomenologically rich particles (scalar leptoquark and fermion triplet) assist in realizing the unification of the gauge couplings associated with the strong and electroweak forces of standard model when embedded in the non-supersymmetric $SO(10)$ grand unified theory. We discuss on unification mass scale and the corresponding proton decay constraints while taking into account the GUT threshold corrections.
- 6 October 2022
- Published by Springer Nature
- p. 9-13
Model Independent Analysis of $B \rightarrow K_1 \mu ^+ \mu ^- $ Decay Processes- 6 October 2022
- Published by Springer Nature
- p. 9-13
Model Independent Analysis of $B \rightarrow K_1 \mu ^+ \mu ^- $ Decay Processes- Open AccessExploring the role of new physics in $b \to u τ\bar ν$ decaysThe recent measurements on $R_D$, $R_{D^*}$ and $R_{J/\psi}$ by three pioneering experiments, BaBar, Belle and LHCb, indicate that the notion of lepton flavour universality is violated in the weak charged-current processes, mediated through $b \to c \ell \bar \nu_\ell$ transitions. These intriguing results, which delineate a tension with their standard model predictions at the level of $(2-3)\sigma$ have triggered many new physics propositions in recent times, and are generally attributed to the possible implication of new physics in $ b \to c \tau \bar \nu$ transition. This, in turn, opens up another avenue, i.e., $ b \to u \tau \bar \nu$ processes, to look for new physics. Since these processes are doubly Cabibbo suppressed, the impact of new physics could be significant enough, leading to sizeable effects in some of the observables. In this work, we investigate in detail the role of new physics in $B \to (\pi,\rho,\omega)\tau \bar \nu$ and $B_s \to (K,K^*) \tau \bar \nu$ processes considering a model independent approach. In particular, we focus on the standard observables like branching fraction, lepton flavour non-universality (LNU) parameter, forward-backward asymmetry and polarization asymmetries. We find significant deviations in some of these observables, which can be explored by the currently running experiments LHCb and Belle-II. We also briefly comment on the impact of scalar leptoquark $R_2(3,2,7/6)$ and vector leptoquark $U_1(3,1,2/3)$ on these decay modes.Open AccessExploring the role of new physics in $b \to u τ\bar ν$ decaysThe recent measurements on $R_D$, $R_{D^*}$ and $R_{J/\psi}$ by three pioneering experiments, BaBar, Belle and LHCb, indicate that the notion of lepton flavour universality is violated in the weak charged-current processes, mediated through $b \to c \ell \bar \nu_\ell$ transitions. These intriguing results, which delineate a tension with their standard model predictions at the level of $(2-3)\sigma$ have triggered many new physics propositions in recent times, and are generally attributed to the possible implication of new physics in $ b \to c \tau \bar \nu$ transition. This, in turn, opens up another avenue, i.e., $ b \to u \tau \bar \nu$ processes, to look for new physics. Since these processes are doubly Cabibbo suppressed, the impact of new physics could be significant enough, leading to sizeable effects in some of the observables. In this work, we investigate in detail the role of new physics in $B \to (\pi,\rho,\omega)\tau \bar \nu$ and $B_s \to (K,K^*) \tau \bar \nu$ processes considering a model independent approach. In particular, we focus on the standard observables like branching fraction, lepton flavour non-universality (LNU) parameter, forward-backward asymmetry and polarization asymmetries. We find significant deviations in some of these observables, which can be explored by the currently running experiments LHCb and Belle-II. We also briefly comment on the impact of scalar leptoquark $R_2(3,2,7/6)$ and vector leptoquark $U_1(3,1,2/3)$ on these decay modes.