The study of light invisible particles in Bc decays

Abstract

In this paper, we study the light scalar and pseudoscalar invisible particles in the flavor changing neutral current processes of the Bc meson. Effective operators are introduced to describe the couplings between quarks and light invisible particles. The Wilson coefficients are extracted from the experimental results of the B and D mesons, which are used to predict the upper limits of the branching fractions of the similar decay processes for the Bc meson. The hadronic transition matrix element is calculated with the instantaneously approximated Bethe-Salpeter method. The upper limits of the branching fractions when mχ taking different values are presented. It is found that at some region of mχ, the channel Bc → Ds(*)χχ has the largest upper limit which is of the order of 10−6, and for Bc → Ds*χχ†, the largest value of the upper limits can achieve the order of 10−5. Other decay modes, such as Bc → D(*)χχ(†) and Bc → B(*)χχ(†), are also considered.