Selection effects for the theta angle of QCD

Contatto di riferimento: Barbara Simoni

Partecipanti: Dr. Lorenzo Ubaldi: SISSA - Trieste

Abstract: After a brief introduction to the strong CP problem, I review the common lore that there is no anthropic argument to select a tiny value of the QCD theta angle. Then I examine a recent proposal that connects the theta-dependent QCD vacuum energy to the cosmological constant. I argue that, even in this case, selection effects do not favor a small value of theta.