Dalitz Plot Analysis of the Decay B0(B0bar) --> K+/- pi-/+ pi0

TL;DR

This paper presents a detailed Dalitz plot analysis of B0 meson decays to K pi pi0, measuring branching fractions, phases, and CP asymmetries, providing insights into decay dynamics and CP violation in charmless B decays.

Contribution

The study provides the first detailed amplitude analysis of B0 --> K pi pi0 decays, including measurements of intermediate resonant contributions and CP asymmetries, with a large data sample from BABAR.

Findings

Measured the inclusive branching fraction BF(B0 --> K+ pi- pi0)=(35.7-1.5+2.6 +/-2.2) x 10^-6.

Observed B0 --> K^{*0}(892) pi^0 decay with BF=(3.6_{-0.8}^{+0.7} +/-0.4) x 10^-6, significant at 5.6 sigma.

Also measured BF(B0 --> D^0bar pi^0)=(2.93 +/- 0.17 +/-0.18) x 10^-4.

Abstract

We report a Dalitz-plot analysis of the charmless hadronic decays of neutral B mesons to K^+/- pi^-/+ pi^0. With a sample of (231.8+/-2.6) 10^6 Upsilon(4S) to B Bbar decays collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC, we measure the magnitudes and phases of the intermediate resonant and nonresonant amplitudes for B0 and B0bar decays and determine the corresponding CP-averaged branching fractions and charge asymmetries. The inclusive branching fraction and CP-violating charge asymmetry are measured to be BF(B0 --> K+ pi^- pi0)=(35.7-1.5+2.6 +/-2.2)10^(-6), and A_CP=-0.030+0.045-0.051 +/-0.055 where the first errors are statistical and the second systematic. We observe the decay B0 --> K^{*0}(892) pi^0 with the branching fraction BF(B0 --> K^{*0}(892) pi^0)=(3.6_{-0.8}^{+0.7} +/-0.4) 10^{-6}. This measurement differs from zero by 5.6 standard deviations (including the systematic uncertainties). The selected sample also contains B0 --> D^0bar pi^0 decays where D^0bar --> K+ pi-, and we measure BF(B0 --> D0bar pi^0)=(2.93 +/- 0.17 +/-0.18) 10^{-4}.