Lattice QCD calculation of $D_s^{*}$ radiative decay using the 2+1 Wilson Clover fermion

Author:

Yu Meng, Jin-Long Dang, Chuan Liu, Zhaofeng Liu, Tinghong Shen, Haobo Yan, Ke-Long Zhang

Keyword:

High Energy Physics - Lattice, High Energy Physics - Lattice (hep-lat), High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph)

journal:

date:

2024-01-24 00:00:00

Abstract

We perform a lattice calculation on the radiative decay of $D_s^*$ using the 2+1 Wilson Clover gauge ensembles generated by CLQCD collaboration. The radiative transition $D_s^*\rightarrow D_s\gamma$ and Dalitz decay $D_s^*\rightarrow D_s e^+e^-$ are studied respectively. After a continuum extrapolation using three lattice spacings, we obtain $\Gamma(D_s^*\rightarrow D_s \gamma)=0.0549(54)$ keV, which is consistent with previous lattice calculations but with much improved precision. The Dalitz decay rate is also calculated for the first time and the ratio with the radiative transition is found to be $R_{ee}=0.624(3)\%$. A total decay width of $D_s^*$ can then be determined as 0.0587(54) keV taking into account the experimental branching fraction. Combining with the most recent experimental measurement on the branching fraction of the purely leptonic decay $D_s^{+,*}\rightarrow e^+\nu_e$, we obtain $f_{D_s^*}|V_{cs}|=(190.5^{+55.1}_{-41.7_{\textrm{stat.}}}\pm 12.6_{\textrm{syst.}})$ MeV, with a significantly improved systematic uncertainty compared to $42.7_{\textrm{syst.}}$ obtained using previous lattice prediction of total decay width $0.070(28)$ keV as input.

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