Rare B Decays with a HyperCP Particle of Spin One

TL;DR

This paper explores the implications of a hypothetical light spin-one particle, potentially explaining HyperCP's observed events, by analyzing its effects on B meson decays and deriving experimental bounds on its properties.

Contribution

It systematically studies the effects of a light spin-one particle with vector and axial-vector couplings on B decays, providing new bounds and guiding future experimental searches.

Findings

Bounds on the particle's couplings derived from current data

Upper limits established for various B decay branching ratios

Guidance for experimental searches for the new particle

Abstract

In light of recent experimental information from the CLEO, BaBar, KTeV, and Belle collaborations, we investigate some consequences of the possibility that a light spin-one particle is responsible for the three Sigma^+ -> p mu^+ mu^- events observed by the HyperCP experiment. In particular, allowing the new particle to have both vector and axial-vector couplings to ordinary fermions, we systematically study its contributions to various processes involving b-flavored mesons, including B-Bbar mixing as well as leptonic, inclusive, and exclusive B decays. Using the latest experimental data, we extract bounds on its couplings and subsequently estimate upper limits for the branching ratios of a number of B decays with the new particle. This can serve to guide experimental searches for the particle in order to help confirm or refute its existence.