Explicit estimate of charm rescattering in $B^0 \to K^0 \bar{\ell} \ell$

Fuente: arXiv
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Main Authors: Isidori, Gino, Polonsky, Zachary, Tinari, Arianna
Format: Preprint
Published: 2024
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author Isidori, Gino
Polonsky, Zachary
Tinari, Arianna
author_facet Isidori, Gino
Polonsky, Zachary
Tinari, Arianna
contents We analyze $B^0 \to K^0 \bar{\ell}\ell$ long-distance contributions induced by the rescattering of a pair of charmed and charmed-strange mesons. We present an explicit estimate of these contributions using an effective description in terms of hadronic degrees of freedom, supplemented by data on the $B^0 \to D^*D_s (D^*_sD)$ transition in order to reproduce the corresponding discontinuity in the $B^0 \to K^0 \bar{\ell}\ell$ amplitude. The $D^* D_s (D^*_s D) K$ vertex is estimated using heavy-hadron chiral perturbation theory, obtaining an accurate description of the whole rescattering process in the low-recoil (or high-$q^2$) limit. We also present an extrapolation to the whole kinematical region introducing hadronic form factors. The explicit estimate of the leading $D^*D_s (D^*_sD)$ intermediate state leads to a long-distance amplitude which does not exceed a few percent relative to the short-distance one. The consequences of this result for the extraction of the short-distance coefficient $C_9$ are discussed.
format Preprint
id arxiv_https___arxiv_org_abs_2405_17551
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Explicit estimate of charm rescattering in $B^0 \to K^0 \bar{\ell} \ell$
Isidori, Gino
Polonsky, Zachary
Tinari, Arianna
High Energy Physics - Phenomenology
We analyze $B^0 \to K^0 \bar{\ell}\ell$ long-distance contributions induced by the rescattering of a pair of charmed and charmed-strange mesons. We present an explicit estimate of these contributions using an effective description in terms of hadronic degrees of freedom, supplemented by data on the $B^0 \to D^*D_s (D^*_sD)$ transition in order to reproduce the corresponding discontinuity in the $B^0 \to K^0 \bar{\ell}\ell$ amplitude. The $D^* D_s (D^*_s D) K$ vertex is estimated using heavy-hadron chiral perturbation theory, obtaining an accurate description of the whole rescattering process in the low-recoil (or high-$q^2$) limit. We also present an extrapolation to the whole kinematical region introducing hadronic form factors. The explicit estimate of the leading $D^*D_s (D^*_sD)$ intermediate state leads to a long-distance amplitude which does not exceed a few percent relative to the short-distance one. The consequences of this result for the extraction of the short-distance coefficient $C_9$ are discussed.
title Explicit estimate of charm rescattering in $B^0 \to K^0 \bar{\ell} \ell$
topic High Energy Physics - Phenomenology
url https://arxiv.org/abs/2405.17551