Helmholtz-Institut für Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Universität Bonn, Bonn, Germany.
Phys Rev Lett. 2012 Aug 10;109(6):062001. doi: 10.1103/PhysRevLett.109.062001.
The issue of chiral extrapolations in heavy quarkonium systems is discussed. We show that the light quark mass dependence of the properties of heavy quarkonia is not always suppressed. For quarkonia close to an open flavor threshold, even a nonanalytic chiral extrapolation is needed. Both these nontrivial facts are demonstrated to appear in the decay widths of the hindered M1 transitions between the first radially excited and ground state P-wave charmonia. The results at a pion mass of about 500 MeV could deviate from the value at the physical pion mass by a factor of two. Our findings show the necessity of performing chiral extrapolations for lattice simulations of heavy quarkonium systems. Furthermore, lattice calculations of these transitions would also provide a definite answer to the role of coupled-channel effects in heavy quarkonium physics due to virtual heavy mesons.
讨论了重夸克偶素系统中的手征外推问题。我们表明，重夸克偶素性质的轻夸克质量依赖性并不总是被抑制。对于接近开放味道阈值的夸克偶素，甚至需要非解析手征外推。这两个非平凡的事实都被证明出现在第一径向激发和基态 P 波魅夸克偶素之间受阻 M1 跃迁的衰变宽度中。在约 500 MeV 的π介子质量下的结果可能偏离物理π介子质量的两倍。我们的发现表明，对于重夸克偶素系统的晶格模拟，进行手征外推是必要的。此外，由于虚拟重介子，这些跃迁的晶格计算也将为重夸克偶素物理中耦合通道效应的作用提供明确的答案。
