Radiative transitions of doubly charmed baryons in lattice QCD
Radiative transitions of doubly charmed baryons in lattice QCD
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DOI：
10.1103/physrevd.98.114505
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发表时间：
2018-07
影响因子：
5
通讯作者：
H. Bahtiyar;K. U. Can;G. Erkol;M. Oka;Toru T. Takahashi
中科院分区：
文献类型：
--
作者：
H. Bahtiyar;K. U. Can;G. Erkol;M. Oka;Toru T. Takahashi
计算了2+1味32^3 × 64$ PACS-CS晶格上双粲重子自旋32到自旋1/2的电磁跃迁.采用相对论性重夸克作用量来减小粲夸克观测量的系统误差。我们提取的磁偶极子，M1 $，和电四极，E2 $，过渡形式的因素。为了使一个可靠的估计M1 $的形状因子，我们进行了分析，包括激发态贡献的影响。我们发现$M1$跃迁占主导地位，轻自由度（$u/d$-或$s$-夸克）起主导作用。$E2$的形状因子，另一方面，被发现是可以忽略不计的小，这反过来，有最小的螺旋度和过渡振幅的影响。在此基础上，我们预测了$\Xi_{cc}^{\ast +，++}$和$\Omega_{cc}^{\ast +}$的衰变宽度和寿命。有限尺寸对这些集合体的影响预计在1%左右。在运动学和动力学因素的差异相对于$N\伽马\\三角洲$过渡进行了讨论，并与非晶格的决定，以及保持可能的系统的文物铭记。与$\Omega_c \gamma \rightarrow \Omega_c^\ast$跃迁作了比较，并讨论了与重夸克作用量选择有关的系统误差。我们在这里提出的结果是特别提示的实验设施，如LHCb，PANDA，贝儿II和BESIII寻找进一步的国家。
We evaluate the spin-$3/2 \to$ spin-$1/2$ electromagnetic transitions of the doubly charmed baryons on 2+1 flavor, $32^3 \times 64$ PACS-CS lattices with a pion mass of $156(9)$ MeV/c$^2$. A relativistic heavy quark action is employed to minimize the associated systematic errors on charm-quark observables. We extract the magnetic dipole, $M1$, and the electric quadrupole, $E2$, transition form factors. In order to make a reliable estimate of the $M1$ form factor, we carry out an analysis by including the effect of excited-state contributions. We find that the $M1$ transition is dominant and light degrees of freedom ($u/d$- or $s$-quark) play the leading role. $E2$ form factors, on the other hand, are found to be negligibly small, which in turn, have minimal effect on the helicity and transition amplitudes. We predict the decay widths and lifetimes of $\Xi_{cc}^{\ast +,++}$ and $\Omega_{cc}^{\ast +}$ based on our results. Finite size effects on these ensembles are expected to be around 1\%. Differences in kinematical and dynamical factors with respect to the $N\gamma\to\Delta$ transition are discussed and compared to non-lattice determinations as well keeping possible systematic artifacts in mind. A comparison to $\Omega_c \gamma \rightarrow \Omega_c^\ast$ transition and a discussion on systematic errors related to the choice of heavy quark action are also given. Results we present here are particularly suggestive for experimental facilities such as LHCb, PANDA, Belle II and BESIII to search for further states.