2019/12/20(Fri)     11:00 -13:00    七樓研討室7th Floor(P7F)


Strong CP violation: from fact to fancy and back


Prof. Goran Senjanovic

International Centre for Theoretical Physics (ICTP), Italy


I demonstrate explicitly that there is no strong CP problem in the Standard Model—and thus there can be no solution to a non-existing problem. I go then through the most popular ‘solutions’ and show how they fare no better than the SM, but simply trade the small strong CP parameter for other ad-hoc assumed small terms. In particular, I focus on the PQ mechanism with the axion and discuss its pros and cons.