$D_{(s)}(2S)$ and $D^{*}_{(s)}(2S)$ production in nonleptonic $B_{(s)}$ weak decays

TL;DR

This paper investigates the production of radially excited heavy mesons in nonleptonic B meson decays using the covariant light-front approach, predicting sizable branching ratios detectable by current experiments.

Contribution

It provides new theoretical predictions for branching ratios of B decays to excited mesons, comparing different models and highlighting channels with large, observable rates.

Findings

Many decay channels have branching ratios between 10^{-5} and 10^{-3}.

Predictions align with RQM and RIQM models but are larger than Bethe-Salpeter results.

Decay polarization fractions are predominantly longitudinal, around 90%.

Abstract

Recently, many new excited states of heavy mesons have been discovered in recent experiments, including radially excited states. The production processes of these states from the $B_{(s)}$ meson have drawn significant interest. In this paper, we use the covariant light-front approach to study the nonleptonic $B_{(s)}$ meson decays to the first radially excited states $D_{(s)}(2S)$ and $D^{*}_{(s)}(2S)$. Our results reveal that many channels exhibit large branching ratios in the range $10^{-5}\sim 10^{-4}$, even up to $10^{-3}$ for individual channels, which are detectable by current experiments. Our predictions for the decays $B_{(s)}\to D^{(*)}_{(s)}(2S)(\pi,\rho,K^{(*)})$ are larger than those given by the Bethe-Salpeter (BS) equation method, but agree well with the relativistic quark mode (RQM) and the relativistic independent quark model (RIQM) calculations. For comparison, we also present the branching ratios of the decays $B_{(s)}\to D^{(*)}_{(s)}(1S)(\pi,\rho,K^{(*)})$, which are comparable with other theoretical results and the data. Although the branching ratios of the decays $B_{(s)} \to D^{*}_{(s)}(1S)(\rho,K^*)$ are much larger than those of the decays $B_{(s)} \to D^{*}_{(s)}(2S)(\rho,K^*)$, the polarization properties between them are similar, that is, the longitudinal polarization fractions are dominant and can amount roughly to $90\%$.