A possible solution to the strong CP problem

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5 Citations (Scopus)


We point out that the long-standing strong CP problem may be resolved by an anthropic argument. The key ideas are: (i) to allow explicit breaking(s) of the Peccei-Quinn symmetry which reduces the strong CP problem to the cosmological constant problem, and (ii) to conjecture that the probability distribution of the vacuum energy has a mild pressure towards higher values. The cosmological problems of the (s)axion with a large Peccei-Quinn scale are absent in our mechanism, since the axion acquires a large mass from the explicit breaking.

Original languageEnglish
Pages (from-to)711-725
Number of pages15
JournalProgress of Theoretical Physics
Issue number4
Publication statusPublished - 2009 Apr


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