Resolved $1/m_b$ contributions to $\bar B \to X_{s,d} \ell^+\ell^-$ and $\bar B \to X_s \gamma$

TL;DR

This paper reanalyzes nonperturbative resolved contributions to certain B meson decays, reducing uncertainties in some cases and clarifying discrepancies with previous analyses.

Contribution

It provides a systematic reanalysis of resolved contributions using new estimates, leading to reduced uncertainties in $ar B o X_{s,d} \, \ell^+\ell^-$ decays and explaining differences with prior work.

Findings

Significant reduction of uncertainties in $\bar B \to X_{s,d} \, \ell^+\ell^-$ decays.

Less reduction of uncertainties in $\bar B \to X_s \gamma$ compared to previous analysis.

Identification of reasons for discrepancies with earlier studies.

Abstract

In view of the importance of the nonperturbative resolved contributions for the overall uncertainties of the two inclusive penguin decays $\bar B \to X_s \gamma$ and $\bar B \to X_{s,d} \ell^+\ell^-$ we reanalyse these contributions using new estimates of moments of the subleading shape functions and of other input parameters. Within a systematic approach we find a significant reduction of the nonperturbative uncertainties in the inclusive decay $\bar B \to X_{s,d} \ell^+\ell^-$, but a much less pronounced reduction in the inclusive decay $\bar B \to X_s \gamma$ compared to a recent analysis on the resolved contributions to the inclusive decay $\bar B \to X_s \gamma$. We identify the reasons for this discrepancy.