A comment on gravitational waves and the scale of supersymmetry breaking

          @misc{ pirsa_PIRSA:10060017,
            doi = {10.48660/10060017},
            url = {https://pirsa.org/10060017},
            author = {Westphal, Alexander},
            keywords = {},
            language = {en},
            title = {A comment on gravitational waves and the scale of supersymmetry breaking},
            publisher = {Perimeter Institute},
            year = {2010},
            month = {jun},
            note = {PIRSA:10060017 see, \url{https://pirsa.org}}
          }
          

Abstract

It has been suggested, by Kallosh and Linde, that a generic bound on inflation in string theory keeps the Hubble scale of inflation $H$ smaller than the gravitino mass, $m_{3/2}$. Given that models with low-energy supersymmetry have $m_{3/2}$ smaller than a TeV, this is a severe constraint, and would suggest that one is forced to choose between high-scale inflation and low-scale supersymmetry. The bound arises by considering possible decompactification instabilities of the extra (compactified) dimensions of string theory, during the inflationary epoch. I explain the arguments that give rise to such a bound, and describe recent work with T. He and A. Westphal exhibiting large-field chaotic inflation models in string-inspired supergravities that have $H >> m_{3/2}$ but avoid decompactification. I conclude that even within the framework of string theory, high-scale inflation and low-energy supersymmetry may well be compatible.