论文标题
使用手性对称性和$ΔI= 1/2 $规则的欧米茄重子的罕见三体衰减的估计值
Estimates for rare three-body decays of the Omega baryon using chiral symmetry and the $ΔI = 1/2$ rule
论文作者
论文摘要
我们使用SU（3）手性扰动理论研究了欧米茄重子的罕见三体衰变，这是低能量下量子染色体动力学的成功有效现场理论。在领先顺序，我们计算衰减$ω^ - \至ξππ$的分支级分，用于所有可能组合的液体组合。对于一个通道，我们发现理论和实验之间的杂音顺序差异。已知这种张力存在于非相关性极限中，我们确认它仍然存在于相对论计算中。相当独立于低能量常数的值，我们为这些三体欧米茄衰变的分支分数建立了下限，这重申了理论和实验之间的差距。我们指出，这种差异与$ΔI= 1/2 $选择规则紧密相关。反过来，这意味着三体衰减构成了审查选择规则的有趣工具。使用近代的订单计算，我们还提供了衰减$ω^ - \至ξ^0μ^ - \barν_μ$的预测。我们表明，完全差异的分布将提供从解剖到八位骨baryon的轴向矢量过渡中所需的低能常数。由于所有这些罕见的三体欧米茄衰变的数据都稀少（完全差异数据不存在），因此我们建议在跑步和即将进行的实验中重新测量它们，例如Besiii，LHCB，Belle-II和Panda。
We study rare three-body decays of the Omega baryon using SU(3) chiral perturbation theory, the successful effective field theory of quantum chromodynamics at low energies. At leading order, we calculate the branching fractions of the decay $Ω^- \to Ξππ$ for all possible combinations of pions. For one channel we find an order-of-magnitude discrepancy between theory and experiment. This tension is known to exist in the non-relativistic limit, and we confirm that it remains in the relativistic calculation. Fairly independent of the values of the low-energy constants we establish lower limits for the branching fractions of these three-body Omega decays, which reaffirm the gap between theory and experiment. We point out that this discrepancy is closely tied to the $ΔI =1/2$ selection rule. In turn, this means that the three-body decays constitute an interesting tool to scrutinize the selection rule. Using next-to-leading order calculations we also provide predictions for the decay $Ω^- \to Ξ^0 μ^- \barν_μ$. We show that fully-differential distributions will provide access to low-energy constants needed in the axial-vector transitions from a decuplet to octet baryon. Since data for all of these rare three-body Omega decays are scarce (fully differential data are nonexistent), we recommend that they be remeasured at running and upcoming experiments, such as BESIII, LHCb, Belle-II, and PANDA.
