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arXiv · 2410.06737

Inclusive rare $\Lambda_b$ decays to photon

Francesco Loparco
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Abstract

Inclusive $H_b \to X_s \, \gamma$ decays, with $H_b$ a beauty baryon, are treated exploiting an expansion up to the third order in the inverse of the $b$ quark mass $m_b$ and to LO in $\alpha_s$, keeping the dependence on the hadron spin. Double distribution $\frac{d^2\Gamma}{dy \, d \cos \theta_P}$ is computed for polarized baryons, with $y = 2 \, E_\gamma / m_b$, $E_\gamma$ the photon energy and $\theta_P$ the angle between the baryon spin vector and the photon momentum in the $H_b$ rest-frame. Modifications to the photon polarization asymmetry can probe effects of physics beyond the Standard Model. A systematic method to treat the singular terms in the photon energy spectrum obtained by the OPE is proposed.

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Francesco Loparco. 2024-10-09. Inclusive rare $\Lambda_b$ decays to photon. https://arxiv.org/abs/2410.06737

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