全粲双粲重子产生过程Ξ_{bc}→H_{cc}+X中的超精细混合与末态自旋再分布

中文摘要 AI 辅助

本工作研究超精细混合对 inclusive 弱衰变Ξ_{bc}→H_{cc}+X的影响，该过程被提议作为寻找 beauty-charmed 重子的有用道。从 inclusive 重 diquark 框架出发，我们包含标量与轴矢量bc组态间的混合，并将末态双粲系统分解为J_f=1/2和J_f=3/2自旋区域。在最小标量到轴矢量流模型中，我们发现各自旋区域内标量与轴矢量分量间的干涉很大，但在对基态ccq自旋多重态的两个成员求和后相互抵消，即Γ_{AS}^{1/2}=-Γ_{AS}^{3/2}。因此，当包含来自自旋激发态Ξ_{cc}^{*}区域的 feed-down 时，inclusive 分支比仍接近原始估计值。然而，直接的基态贡献具有强自旋选择性：Ξ_{bc}^{(1)}主要衰变为J_f=1/2的Ξ_{cc}道，而Ξ_{bc}^{(2)}主要衰变为J_f=3/2的Ξ_{cc}^{*}道。我们还在混合角、标量流归一化和反冲形状选择的变化下检验上述结论的稳定性，发现超精细混合隐藏在总 inclusive 率中，但可通过末态自旋组成揭示出来。

英文摘要

In this work, we study the effect of hyperfine mixing on the inclusive weak transition $Ξ_{bc}\to H_{cc}+X$, which has been proposed as a useful channel for searching for beauty-charmed baryons. Starting from the inclusive heavy-diquark framework, we include mixing between the scalar and axial-vector $bc$ configurations and decompose the final doubly charmed system into the $J_f=1/2$ and $J_f=3/2$ spin sectors. Within a minimal scalar-to-axial transition model, and for a benchmark scalar-channel normalization of order unity at zero recoil, we find that the interference between the scalar and axial components is large in the separate spin sectors but cancels after summing over the two members of the adopted ground-state $ccq$ spin multiplet, $Γ_{AS}^{1/2}=-Γ_{AS}^{3/2}$. Consequently, the spin-summed inclusive rate is less sensitive to hyperfine mixing than the direct ground-state contribution, provided feed-down from the spin-excited $Ξ_{cc}^{*}$ partner is experimentally unresolved. For a scalar-channel normalization of order unity, the direct contribution can be strongly spin selective: $Ξ_{bc}^{(1)}$ dominantly feeds the $J_f=1/2$ $Ξ_{cc}$ channel, whereas $Ξ_{bc}^{(2)}$ dominantly feeds the $J_f=3/2$ $Ξ_{cc}^{*}$ sector. We test this pattern for several convention-matched literature admixtures and for a separately labeled decay-interference diagnostic angle, together with the dependence on the scalar-to-axial normalization and recoil-shape choice. The cancellation of the spin-summed interference is a consequence of baryon spin recoupling within the spectator and common-multiplet assumptions, whereas the magnitude of the spin selectivity is conditional on the magnitude and relative phase of the scalar-to-axial transition.

发表机构

• National Center for Physics（国家物理中心）

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