Theoretical corrections of and

Xin-Xin Long; Shu-Min Zhao; Ming-Yue Liu; Xi Wang; Yi-Tong Wang; Zhong-Jun Yang; Xing-Xing Dong; Tai-Fu Feng

doi:10.1140/epjc/s10052-023-12091-9

2024 Impact factor 4.8

Particles and Fields

Open Access

Eur. Phys. J. C (2023) 83: 920
https://doi.org/10.1140/epjc/s10052-023-12091-9

Regular Article - Theoretical Physics

Theoretical corrections of $R_{D}$ and $R_{D^{}}$ $R_{D^}$

Xin-Xin Long¹^,2^,3, Shu-Min Zhao¹^,2^,3^b, Ming-Yue Liu¹^,2^,3, Xi Wang¹^,2^,3, Yi-Tong Wang¹^,2^,3, Zhong-Jun Yang⁴, Xing-Xing Dong¹^,2^,3 and Tai-Fu Feng¹^,2^,3^,4

¹ Department of Physics, Hebei University, 071002, Baoding, China
² Key Laboratory of High-precision Computation and Application of Quantum Field Theory of Hebei Province, 071002, Baoding, China
³ Research Center for Computational Physics of Hebei Province, 071002, Baoding, China
⁴ Department of Physics, Chongqing University, 401331, Chongqing, China

^b zhaosm@hbu.edu.cn

Received: 30 June 2023
Accepted: 27 September 2023
Published online: 12 October 2023

Abstract

$R_{D^{(*)}}$ $R_{D^{(*)}}$ is the ratio of branching ratio $\bar{B} \to D^{(*)} τ {\bar{ν}}_{τ}$ $\overline{B} \rightarrow D^{(*)}\tau \overline{\nu }_{\tau }$ to $\bar{B} \to D^{(*)} l {\bar{ν}}_{l} (l = e, μ)$ $\overline{B} \rightarrow D^{(*)}l\overline{\nu }_{l}~(l=e,~\mu )$ . There is a gap of 2 $σ_{\exp}$ $\sigma _{exp}$ or more between its experimental value and the prediction under the standard model (SM). People extend the MSSM with the local gauge group $U {(1)}_{X}$ $$U(1)_X$$ to obtain the $U {(1)}_{X}$ SSM. Compared with MSSM, $U {(1)}_{X}$ SSM has more superfields and effects. In $U {(1)}_{X}$ SSM, we research the semileptonic decays $\bar{B} \to D^{(*)} l {\bar{ν}}_{l}$ $\overline{B} \rightarrow D^{(*)}l\overline{\nu }_{l}$ and calculate $R_{D^{(*)}}$ $R_{D^{(*)}}$ . The numerical results of $R_{D^{(*)}}$ $R_{D^{(*)}}$ are further corrected under $U {(1)}_{X}$ $$U(1)_X$$ SSM, which are much better than the SM predictions. After correction, the theoretical value of $R_{D^{(*)}}$ $R_{D^{(*)}}$ can reach one $σ_{\exp}$ $\sigma _{exp}$ range of the averaged experiment central value.

© The Author(s) 2023

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