Measurement of the CKM angle $\gamma$ from a combination of LHCb results

TL;DR

This paper combines multiple LHCb measurements of B meson decays to precisely determine the CKM angle gamma, achieving a value of approximately 72 degrees with systematic uncertainties considered.

Contribution

It provides the first comprehensive combination of various LHCb results to measure the CKM angle gamma, including both time-integrated and time-dependent decay analyses.

Findings

Measured gamma as (72.2^{+6.8}_{-7.3}) degrees.

Established a 95.5% confidence interval for gamma between 55.9 and 85.2 degrees.

Demonstrated consistency across different decay channels and analysis methods.

Abstract

A combination of measurements sensitive to the CKM angle $\gamma$ from LHCb is performed. The inputs are from analyses of time-integrated $B^{+}\rightarrow DK^+$, $B^{0} \rightarrow D K^{*0}$, $B^{0} \rightarrow D K^+ \pi^-$ and $B^{+} \rightarrow D K^+\pi^+\pi^-$ tree-level decays. In addition, results from a time-dependent analysis of $B_{s}^{0} \rightarrow D_{s}^{\mp}K^{\pm}$ decays are included. The combination yields $\gamma = (72.2^{+6.8}_{-7.3})^\circ$, where the uncertainty includes systematic effects. The 95.5% confidence level interval is determined to be $\gamma \in [55.9,85.2]^\circ$. A second combination is investigated, also including measurements from $B^{+} \rightarrow D \pi^+$ and $B^{+} \rightarrow D \pi^+\pi^-\pi^+$ decays, which yields compatible results.