Charmless B decays in modes with similar tree and penguin contributions

TL;DR

This paper discusses how charmless B decays, influenced by tree and penguin amplitudes, exhibit CP asymmetries that vary across phase space, with recent LHCb analyses providing experimental insights.

Contribution

It analyzes the interplay of tree and penguin contributions in charmless B decays and discusses recent LHCb measurements of CP asymmetries and angular distributions.

Findings

CP asymmetries vary across the Dalitz plot in three-body decays.

LHCb observed CP asymmetries in $B^ op o \pi^ op \pi^+\pi^-$ and $B^ op o \pi^ op ext{K}^+ ext{K}^-$ decays.

Angular analysis of $B^0 o \phi K^*(892)^0$ provides insights into decay dynamics.

Abstract

Charmless $B$ decays are dominated by contributions from the short distance amplitudes from tree level and penguin loop-level amplitudes. The Tree contribution presents a weak phase $\gamma$. The relationship between these two amplitudes can generated a CP asymmetry depending from the relative amount among them in a particular decay. In multi-body charmless $B$ decays, these relative contribution can change along the phase space, given a non isotropic distribution of CP asymmetries in the Dalitz plot. Two recent LHCb analyses involving charmless multi-body B decays are discussed: the obsevation of CP asymmetries in the phase space of the three-body decays $B^\pm \to \pi^\pm \pi^+ \pi^-$ and $B^\pm \to \pi^\pm K^+ K^-$; and the angular analysis of the $B^0 \to \phi K^*(892)^0$ decay.