一週間前になりますが、年度末３月３１日に新潟大学の谷本さんにセミナーをしていただきました。退官されてからも研究だけでなく社会的活動でもご活躍されている様子に、我々も頑張らねばと新年度心新たにしました。
タイトル：”Modular invariance and the strong CP problem”
概要：We present simple effective theory of quark masses, mixing and CP violation with the modular symmetry, which provides solution to the strong CP problem without the need for an axion. The vanishing of the strong CP-violating phase is ensured by assuming CP to be a fundamental symmetry of the Lagrangian of the theory. The CP symmetry is broken spontaneously by the vacuum expectation value (VEV) of the modulus τ. This provides the requisite large value of the CKM CP-violating phase while the strong CP phase remains zero or is tiny. Within the considered framework we discuss phenomenologically viable quark mass matrices. We also discuss cases in which the modulus VEV is close to the fixed points of modulus.
