Excited doubly heavy baryons production via top-quark decays

Abstract

Within the framework of NRQCD, we calculate the production of excited doubly heavy baryons ${\Xi }_{bQ}$ through the semi-inclusive production process $t\to ⟨bQ⟩[n]\to {\Xi }_{bQ}+\bar{Q}+W^{+}$, where $Q=b$ or $c$ quark. The intermediate diquark state $⟨bQ⟩[n]$ is in the excited $P$-wave state, including ${[}^1{P}_1]$ and ${[}^3{P}_J]$ ($J=$0, 1 or 2) in both color antitriplet state $\overline{3}$ and color sixtuplet state $6$, that is, $⟨bc⟩{[}^1{P}_1{]}_{\overline{3}/6}$, $⟨bc⟩{[}^3{P}_J{]}_{\overline{3}/6}$, $⟨bb⟩{[}^1{P}_1{]}_{\overline{3}}$, and $⟨bb⟩{[}^3{P}_J{]}_6$. We find that the contributions from the P-wave states are about one order lower than the S-wave contributions, and this conclusion is consistent with others. We also analyze the invariant mass and angle differential distributions, and the theoretical uncertainty from the mass parameters and the renormalization scale. Finally, we can expect that about $1.14\times 10^{3-5}$ events of excited ${\Xi }_{bc}$ and $2.47\times 10^{1-3}$ events of excited ${\Xi }_{bb}$ can be produced per year at the LHC or HL-LHC with $\mathcal{L}$ =$10^{34-36}{\mathrm{cm}}^{-2}{\mathrm{s}}^{-1}$.

Comments: 11 pages, 5 figures, 7 tables. Some typos have been corrected and rewrite some sentences. arXiv admin note: text overlap with arXiv:1810.03834