arXiv 1710.066432017-10-18hep-lat

具有单个轻夸克味的拓扑磁化率

Topological susceptibility with a single light quark flavour

Julien Frison, Ryuichiro Kitano, Norikazu Yamada

备注：: 8 pages, 3 figures, Presented at Lattice2017, the 35th International Symposium on Lattice Field Theory at Granada, Spain (18-24 June 2017)
DOI：: 10.1051/epjconf/201817514017

摘要：

解决强CP问题的一个历史建议是在保持$m_d$有限的同时，将上夸克质量取为零。然后假设$θ$角变得无关紧要，即拓扑磁化率消失。然而，夸克质量的定义是依赖于图式的，并且识别$m_u=0$点并不简单，特别是对于类威尔逊费米子。更具体地说，据我们所知，没有理论论据保证拓扑磁化率在PCAC质量消失时完全消失。我们将介绍我们最近的进展经验检查这个属性使用$N_f=1+2$味道的三叶草费米子，其中最轻的费米子被调谐非常接近$m^{PCAC}_u$ =0和其他两个的质量保持的物理$m_s$的数量级。这种选择确实预期会放大由$m_u\not=m_d$引起的任何未知的非微扰效应。对几个$β$重复模拟，这些结果虽然是初步的，但给出了关于在连续极限中发生的情况的提示。

英文摘要：

One of the historical suggestions to tackle the strong CP problem is to take the up quark mass to zero while keeping $m_d$ finite. The $θ$ angle is then supposed to become irrelevant, i.e. the topological susceptibility vanishes. However, the definition of the quark mass is scheme-dependent and identifying the $m_u=0$ point is not trivial, in particular with Wilson-like fermions. More specifically, up to our knowledge there is no theoretical argument guaranteeing that the topological susceptibility exactly vanishes when the PCAC mass does. We will present our recent progresses on the empirical check of this property using $N_f=1+2$ flavours of clover fermions, where the lightest fermion is tuned very close to $m^{PCAC}_u$=0 and the mass of the other two is kept of the order of magnitude of the physical $m_s$. This choice is indeed expected to amplify any unknown non-perturbative effect caused by $m_u\not=m_d$. The simulation is repeated for several $β$s and those results, although preliminary, give a hint about what happens in the continuum limit.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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英文摘要：

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