Study of $B_c^+\to J/\psi D_s^+$ and $B_c^+\to J/\psi D_s^{*+}$ decays in $pp$ collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector

The collaboration
JHEP 08 (2022) 087, 2022.

Abstract (data abstract)
A study of the $B_c^+\to J/\psi D_s^+$ and $B_c^+\to J/\psi D_s^{*+}$ decays using 139\,fb$^{-1}$ of integrated luminosity collected with the ATLAS detector from $\sqrt{s} = 13$\,TeV $pp$ collisions at the LHC is presented. The ratios of the branching fractions of the two decays to the branching fraction of $B_c^+\to J/\psi \pi^+$ decay channel are measured: $\mathcal B(B_c^+\to J/\psi D_s^+)/\mathcal B(B_c^+\to J/\psi \pi^+) = 2.76\pm 0.33\pm 0.29\pm 0.16$, $\mathcal B(B_c^+\to J/\psi D_s^{*+})/\mathcal B(B_c^+\to J/\psi \pi^+) = 5.33\pm0.61\pm 0.67\pm 0.32$. Here the first error is statistical, the second is systematic, and the third is due to uncertainty on the $D_s^+\to\phi(K^+ K^-)\pi^+$ decay branching fraction. The ratio between the branching fractions of the two decays is found to be $\mathcal B(B_c^+\to J/\psi D_s^{*+})/\mathcal B(B_c^+\to J/\psi D_s^+) = 1.93\pm0.24 \pm 0.09$. For the $B_c^+\to J/\psi D_s^{*+}$ decay, the transverse polarisation fraction, $\Gamma_{\pm\pm}/\Gamma$, is measured to be $0.70\pm0.10\pm 0.04$. The precision of the measurements exceeds that of all previous studies of these decays.

• #### Table 1

Results of Eqs. 6-9 and Tables 4 and 5.

10.17182/hepdata.126990.v1/t1

Measured values of $R_{D_s^+/\pi^+}$, $R_{D_s^{*+}/\pi^+}$, $R_{D_s^{*+}/D_s^+}$ ratios of branching fractions, fraction of transverse polarization $\Gamma_{\pm\pm}/\Gamma$ with their statistical uncertainties and...

• #### Table 2

Results of Table 1.

10.17182/hepdata.126990.v1/t2

Parameters of the $B_c^+\to J/\psi D_s^+$ and $B_c^+\to J/\psi D_s^{*+}$ signals obtained with the unbinned extended maximum-likelihood fit to the...

• #### Table 3

Results of Table 2.

10.17182/hepdata.126990.v1/t3

Parameters of the $B_c^+\to J/\psi \pi^+$ signal obtained with the unbinned extended maximum-likelihood fit. Only the statistical uncertainties are included....

• #### Table 4

Results of Table 3.

10.17182/hepdata.126990.v1/t4

Summary of the total efficiencies. Quoted uncertainties correspond to statistical uncertainties of the simulated samples used. For the \$B_c^+\to J/\psi...

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