有限尺寸夸克-双夸克模型中多重重子的谱与无轻子衰变
Spectra and nonleptonic decays of multiply heavy baryons in a finite-size quark-diquark model
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中文总结 AI 辅助
本研究在有限尺寸夸克-双夸克模型中计算多重重子质量谱与无轻子衰变，质量与格点QCD差异小于1.5%，并揭示b→c衰变宽度因重叠和CKM层级减小约两个数量级。
中文摘要 AI 辅助
我们在非相对论夸克-双夸克模型中研究了基态双重和三重重子的质量谱及两体无轻子弱衰变。为考虑双夸克的有限尺寸，我们利用质量加权组分坐标和不同的成对自旋-自旋耦合，将卷积夸克-双夸克相互作用推广到不等质量双夸克情形。由此得到的薛定谔方程提供了重子质量和波函数，并一致地用于衰变计算。预测质量与现有格点QCD结果的差异小于1.5%，且我们计算的Ω_cc^+质量与近期LHCb观测一致。计算出的超精细劈裂系统地略小于格点值，表明自旋相关相互作用存在残余不确定性。在因子化近似下，我们评估了伴随π或K介子发射的c→s和b→c跃迁。在领头非相对论阶，矢量贡献在3/2^+→1/2^+跃迁中消失，而矢量和轴矢贡献均进入3/2^+→3/2^+通道。b→c空间重叠显著小于对应的c→s重叠。结合Cabibbo-Kobayashi-Maskawa层级，这使相应的b→c宽度减小约两个数量级。在3/2^+→1/2^+粲跃迁中，领头|k|^3依赖性增强了对K介子发射的抑制。在能量释放更大的底跃迁中，较小的相对相空间差异使比值接近由Cabibbo-Kobayashi-Maskawa矩阵元和介子衰变常数决定的标度。这些结果为未来多重重子研究提供了基准估计，并量化了有限尺寸夸克-双夸克框架内反冲动力学的作用。
英文摘要
We investigate the mass spectra and two-body nonleptonic weak decays of ground-state doubly and triply heavy baryons in a nonrelativistic quark-diquark model. To account for the finite size of the diquark, we generalize the convoluted quark-diquark interaction to unequal-mass diquarks using mass-weighted constituent coordinates and distinct pairwise spin-spin couplings. The resulting Schr{ö}dinger equations provide the baryon masses and wave functions used consistently in the decay calculation. The predicted masses differ from existing lattice QCD results by less than $1.5\%$, and our calculated mass of $Ω_{cc}^{+}$ is consistent with recent LHCb observations. The calculated hyperfine splittings are systematically slightly smaller than the lattice values, indicating a residual uncertainty in the spin-dependent interaction. Within the factorization approximation, we evaluate the $c\to s$ and $b\to c$ transitions with pion or kaon emission. At leading nonrelativistic order, the vector contribution vanishes for the $3/2^+\to1/2^+$ transitions, while both vector and axial contributions enter the $3/2^+\to3/2^+$ channels. The $b\to c$ spatial overlaps are substantially smaller than their $c\to s$ counterparts. Together with the Cabibbo-Kobayashi-Maskawa hierarchy, this reduces the corresponding $b \to c$ width by approximately two orders of magnitude. In the $3/2^+\to1/2^+$ charm transitions, the leading $|\bm{k}|^3$ dependence enhances the suppression of kaon emission. In bottom transitions with a larger energy release, the smaller relative phase-space difference brings the ratios close to the scaling determined by the Cabibbo-Kobayashi-Maskawa elements and meson decay constants. These results provide benchmark estimates for future studies of multiply heavy baryons and quantify the role of recoil dynamics within the finite-size quark-diquark framework.
发表机构
- College of Physics, Chengdu University of Technology（成都理工大学物理学院）
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