We investigate the decays <InlineEquation ID="IEq4"> <EquationSource Format="MATHML"><math display="inline"> <msubsup> <mi>B</mi> <mi>c</mi> <mo>−</mo> </msubsup> </math></EquationSource> <EquationSource Format="TEX">$ {B}_c^{-} $</EquationSource> </InlineEquation> → <InlineEquation ID="IEq5"> <EquationSource Format="MATHML"><math display="inline"> <msup> <mover accent="true"> <mi>D</mi> <mo stretchy="true">¯</mo> </mover> <mrow> <mfenced close=")" open="("> <mo>∗</mo> </mfenced> <mn>0</mn> </mrow> </msup> <msup> <mi>ℓ</mi> <mo>−</mo> </msup> <msub> <mover accent="true"> <mi>ν</mi> <mo stretchy="true">¯</mo> </mover> <mi>ℓ</mi> </msub> </math></EquationSource> <EquationSource Format="TEX">$ {\overline{D}}^{\left(\ast \right)0}{\ell}^{-}{\overline{\nu}}_{\ell } $</EquationSource> </InlineEquation> and <InlineEquation ID="IEq6"> <EquationSource Format="MATHML"><math display="inline"> <msubsup> <mi>B</mi> <mi>c</mi> <mo>−</mo> </msubsup> </math></EquationSource> <EquationSource Format="TEX">$ {B}_c^{-} $</EquationSource> </InlineEquation> → D(∗)−ℓ+ℓ− within the Standard Model (SM), employing perturbative QCD (pQCD) form factors that are sensitive to the wave functions of Bc and D(∗) mesons. Using lattice QCD inputs for B → D(∗) and Bc → D transitions, we extract the shape parameters of the meson wave functions and estimate the q2-dependence of Bc → D∗ form factors via heavy quark spin symmetry. We present predictions for branching fractions, lepton flavor violating observables, and perform a detailed angular analysis of the cascade decay <InlineEquation ID="IEq7"> <EquationSource Format="MATHML"><math display="inline"> <msubsup> <mi>B</mi> <mi>c</mi> <mo>−</mo> </msubsup> </math></EquationSource> <EquationSource Format="TEX">$ {B}_c^{-} $</EquationSource> </InlineEquation> → D∗−(→ D0π−)ℓ+ℓ−, providing SM expectations for several angular observables.

Study of form factors and observables in $ {B}_c^{-} $ → $ {\overline{D}}^{\left(\ast \right)0}{\ell}^{-}{\overline{\nu}}_{\ell } $ and $ {B}_c^{-} $ → D^(∗)−ℓ⁺ℓ⁻ decays

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2026年4月14日

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Utsab Dey,
Soumitra Nandi

摘要

We investigate the decays $B_{c}^{-}$ $ {B}_c^{-} $ → ${\bar{D}}^{(*) 0} ℓ^{-} {\bar{ν}}_{ℓ}$ $ {\overline{D}}^{\left(\ast \right)0}{\ell}^{-}{\overline{\nu}}_{\ell } $ and $B_{c}^{-}$ $ {B}_c^{-} $ → D^(∗)−ℓ⁺ℓ⁻ within the Standard Model (SM), employing perturbative QCD (pQCD) form factors that are sensitive to the wave functions of B_c and D^(∗) mesons. Using lattice QCD inputs for B → D^(∗) and B_c → D transitions, we extract the shape parameters of the meson wave functions and estimate the q²-dependence of B_c → D^∗ form factors via heavy quark spin symmetry. We present predictions for branching fractions, lepton flavor violating observables, and perform a detailed angular analysis of the cascade decay $B_{c}^{-}$ $ {B}_c^{-} $ → D^∗−(→ D⁰π⁻)ℓ⁺ℓ⁻, providing SM expectations for several angular observables.

Study of form factors and observables in \( {B}_c^{-} \) → \( {\overline{D}}^{\left(\ast \right)0}{\ell}^{-}{\overline{\nu}}_{\ell } \) and \( {B}_c^{-} \) → D(∗)−ℓ+ℓ− decays

摘要

Study of form factors and observables in \( {B}_c^{-} \) → \( {\overline{D}}^{\left(\ast \right)0}{\ell}^{-}{\overline{\nu}}_{\ell } \) and \( {B}_c^{-} \) → D^(∗)−ℓ⁺ℓ⁻ decays