Electromagnetic transitions of $(b{\bar c})$ bound system

TL;DR

This paper predicts electromagnetic transition form factors and decay widths for various $B_c$ meson states using a relativistic quark model, aiding future experimental identification and understanding of the $B_c$ meson family.

Contribution

It provides novel predictions of transition form factors and decay widths for $B_c$ mesons within a relativistic quark model, including excited states, consistent with other theoretical approaches.

Findings

Predicted decay widths align with Bethe-Salpeter model results.

Provided transition form factors for ground and excited $B_c$ states.

Suggested experimental relevance for LHCb and $Z^0$ factory measurements.

Abstract

We study electromagnetic transitions: $B_c^*(ns)\to B_c(ns) e^+ e^-$, $B_c^*(ns)\to B_c(n^{\prime}s) e^+ e^-$ and $B_c(ns)\to B^*_c(n^{\prime}s) e^+ e^-$ in the relativistic independent quark (RIQ) model based on a flavor-independent potential in the scalar-vector harmonic form. The transition form factors for energetically possible transitions involving $B_c$ - and $B_c^*$- mesons in ground as well as orbitally excited states are predicted in their respective kinematic range. Our predictions on decay width for the allowed and hindered transitions are found compatible with those of the model calculations based on Bethe-Salpeter approach. Predictions in this sector would not only provide more information about members of the $B_c$-family including mass splitting between vector mesons and corresponding pseudoscalar counterparts but give hints for experimental determination of unknown masses of other excited $B_c$ - and ground state of $B_c^*$-meson, which is expected at LHCb and $Z^0$ factory in near future.