Production of excited doubly heavy baryons at the super-Z factory

Juan-Juan Niu; Jing-Bo Li; Huan-Yu Bi; Hong-Hao Ma

doi:10.1140/epjc/s10052-023-11958-1

2023 Impact factor 4.2

Particles and Fields

Open Access

Eur. Phys. J. C (2023) 83: 822
https://doi.org/10.1140/epjc/s10052-023-11958-1

Regular Article - Theoretical Physics

Production of excited doubly heavy baryons at the super-Z factory

Juan-Juan Niu¹^,2, Jing-Bo Li¹, Huan-Yu Bi³^,4 and Hong-Hao Ma¹^,2^d

¹ Department of Physics, Guangxi Normal University, 541004, Guilin, China
² Guangxi Key Laboratory of Nuclear Physics and Technology, Guangxi Normal University, 541004, Guilin, China
³ Center for High Energy Physics, Peking University, 100871, Beijing, China
⁴ School of Physics, Peking University, 100871, Beijing, China

^d mahonghao@pku.edu.cn

Received: 23 June 2023
Accepted: 24 August 2023
Published online: 14 September 2023

Abstract

In the framework of nonrelativistic QCD, the excited doubly heavy baryons are thoroughly studied via the channel $e^{+} e^{-} \to ⟨ Q Q^{'} ⟩ [n] \to Ξ_{Q Q^{'}} + \bar{Q^{'}} + \bar{Q}$ $e^{+} e^{-}\rightarrow \langle QQ^{\prime }\rangle [n] \rightarrow \Xi _{QQ^{\prime }} +\bar{Q^{\prime }} +{\bar{Q}}$ , which takes place at the collision energy Z-pole. $Q^{(')}$ $Q^{(\prime )}$ represents b or c quark for the production of $Ξ_{cc}$ $\Xi _{cc}$ , $Ξ_{bc}$ $\Xi _{bc}$ , and $Ξ_{bb}$ $\Xi _{bb}$ , respectively. All of the intermediate diquark states $⟨ Q Q^{'} ⟩ [n]$ $\langle QQ'\rangle [n]$ in P-wave, $⟨ c c ⟩ {[^{1} P_{1}]}_{\bar{3}}$ $\langle cc\rangle [^{1}P_{1}]_{{\bar{\textbf{3}}}}$ , $⟨ c c ⟩ {[^{3} P_{J}]}_{6}$ $\langle cc\rangle [^{3}P_{J}]_{{\textbf{6}}}$ , $⟨ b c ⟩ {[^{1} P_{1}]}_{\bar{3} / 6}$ $\langle bc\rangle [^{1}P_{1}]_{{\bar{\textbf{3}}}/ {\textbf{6}}}$ , $⟨ b c ⟩ {[^{3} P_{J}]}_{\bar{3} / 6}$ $\langle bc\rangle [^{3}P_{J}]_{{\bar{\textbf{3}}}/ {\textbf{6}}}$ , $⟨ b b ⟩ {[^{1} P_{1}]}_{\bar{3}}$ $\langle bb \rangle [^{1}P_{1}]_{{\bar{\textbf{3}}}}$ , and $⟨ b b ⟩ {[^{3} P_{J}]}_{6}$ $\langle bb\rangle [^{3}P_{J}]_{{\textbf{6}}}$ with $J = 0$ $$J=0$$ , 1, or 2, are taken into account. The cross sections and differential distributions, including the transverse momentum, rapidity, angular, and invariant mass, are discussed for the excited baryons production. We find that the contributions of $⟨ c c ⟩$ $\langle cc \rangle$ , $⟨ b c ⟩$ $\langle bc \rangle$ , and $⟨ b b ⟩$ $\langle bb \rangle$ in P-wave are found to be 3.97 $%$ $\%$ , 5.08 $%$ $\%$ , and 5.89 $%$ $\%$ , respectively, compared to S-wave. Supposing that all excited states can decay into the ground state 100%, the total events $N_{Ξ_{cc}} = 8.48 \times 10^{4 - 6}$ $N_{\Xi _{cc}}=8.48 \times 10^{4-6}$ , $N_{Ξ_{bc}} = 2.26 \times 10^{5 - 7}$ $N_{\Xi _{bc}}=2.26\times 10^{5-7}$ , and $N_{Ξ_{bb}} = 4.12 \times 10^{3 - 5}$ $N_{\Xi _{bb}}=4.12 \times 10^{3-5}$ would be produced at the Super-Z Factory with a high luminosity up to $L ≃ 10^{34 - 36} {cm}^{- 2} s^{- 1}$ ${{\mathcal {L}}} \simeq 10^{34-36}\textrm{cm}^{-2} \textrm{s}^{-1}$ .

© The Author(s) 2023

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