The Standard Model Prediction for the Rare Decay $B \to X_s ν\bar ν$

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Fael, Matteo, Jenkins, Jack, Lunghi, Enrico, Polonsky, Zachary
Format: Preprint
Published: 2025
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866914214139920384
author Fael, Matteo
Jenkins, Jack
Lunghi, Enrico
Polonsky, Zachary
author_facet Fael, Matteo
Jenkins, Jack
Lunghi, Enrico
Polonsky, Zachary
contents We present updated and comprehensive Standard Model predictions for the inclusive rare decay $B \to X_s ν\barν$. Using a state-of-the-art determination of the short-distance coefficient, including NLO QCD and electroweak effects, and implementing a consistent treatment of heavy-quark masses and power corrections within the kinetic scheme, we compute the total decay rate and the neutrino invariant mass spectrum. We incorporate all known perturbative contributions in the heavy quark limit up to $\mathcal{O}(α_s^3)$, evaluate non-perturbative corrections through the Heavy Quark Expansion up to $1/m_b^3$, and include estimates of four-quark operator matrix elements from HQET sum rules. We obtain the Standard Model branching ratios $\text{Br}(B^0 \to X_sν\barν) = (3.35 \pm 0.10)\times 10^{-5} $ and $ \text{Br}(B^+ \to X_sν\barν) = (3.62 \pm 0.11)\times 10^{-5}, $ representing a significant improvement in both central value and precision compared to previous determinations. We also provide predictions for partial rates with kinematic cuts relevant to Belle II. Our results are timely in view of recent measurements of $B \to Kν\barν$ and the first upper limits on inclusive $B \to X_sν\barν$, and they offer a robust baseline for future searches for physics beyond the Standard Model in $b\to sν\barν$ transitions.
format Preprint
id arxiv_https___arxiv_org_abs_2512_19138
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The Standard Model Prediction for the Rare Decay $B \to X_s ν\bar ν$
Fael, Matteo
Jenkins, Jack
Lunghi, Enrico
Polonsky, Zachary
High Energy Physics - Phenomenology
High Energy Physics - Experiment
We present updated and comprehensive Standard Model predictions for the inclusive rare decay $B \to X_s ν\barν$. Using a state-of-the-art determination of the short-distance coefficient, including NLO QCD and electroweak effects, and implementing a consistent treatment of heavy-quark masses and power corrections within the kinetic scheme, we compute the total decay rate and the neutrino invariant mass spectrum. We incorporate all known perturbative contributions in the heavy quark limit up to $\mathcal{O}(α_s^3)$, evaluate non-perturbative corrections through the Heavy Quark Expansion up to $1/m_b^3$, and include estimates of four-quark operator matrix elements from HQET sum rules. We obtain the Standard Model branching ratios $\text{Br}(B^0 \to X_sν\barν) = (3.35 \pm 0.10)\times 10^{-5} $ and $ \text{Br}(B^+ \to X_sν\barν) = (3.62 \pm 0.11)\times 10^{-5}, $ representing a significant improvement in both central value and precision compared to previous determinations. We also provide predictions for partial rates with kinematic cuts relevant to Belle II. Our results are timely in view of recent measurements of $B \to Kν\barν$ and the first upper limits on inclusive $B \to X_sν\barν$, and they offer a robust baseline for future searches for physics beyond the Standard Model in $b\to sν\barν$ transitions.
title The Standard Model Prediction for the Rare Decay $B \to X_s ν\bar ν$
topic High Energy Physics - Phenomenology
High Energy Physics - Experiment
url https://arxiv.org/abs/2512.19138