CP Asymmetries in B->K pi, K*pi, rho K Decays

TL;DR

This paper analyzes CP asymmetries in B meson decays to K pi, K* pi, and rho K, showing larger potential asymmetries and proposing sum rules to test the Standard Model and search for new physics at future experiments.

Contribution

It introduces isospin sum rules for rate asymmetries in B decays and estimates their violations, providing a framework for precision tests of the Standard Model and new physics searches.

Findings

Ratios of tree and penguin amplitudes are larger in B->K*pi and B->rho K than in B->K pi.

CP asymmetries in B->K*pi and B->rho K can be significantly larger than in B->K pi.

Sum rule violations are small, around 1-2%, and can be tested at LHCb and future facilities.

Abstract

We show that ratios of tree and penguin amplitudes in B-> K*pi and B->rho K are two to three times larger than in B-> K pi. This allows for considerably larger CP asymmetries in the former processes than the 10% asymmetry measured in B0 -> K+pi-. We study isospin sum rules for rate asymmetries in B-> K pi, K*pi, rho K, estimating small violation from interference of tree and electroweak penguin amplitudes. The breaking of the K pi asymmetry sum rule is estimated to be one to two percent and negative. Violation of K*pi and rho K sum rules can be estimated from B->rho pi amplitudes using flavor SU(3), while breaking of a sum rule combining K*pi and rho K asymmetries can be measured directly in a Dalitz analysis of B0-> K+pi-pi0. The three sum rules can be tested at the LHCb and at a future Super Flavor Factory, providing precision searches for new Delta S =Delta I=1 operators in the low energy effective Hamiltonian.