## November 14, 2003

### Stanford Old Home Week

We have both Keshav Dasgupta and Scott Thomas visiting from Stanford this week.

Keshav gave a very nice talk about $N=1$ supersymmetric compactifications of Heterotic strong theory with nonzero H-flux. We’re not talking about spacetimes of the form AdS4$\times$ Calabi-Yau, which have been the subject of much recent interest. Instead, we’re talking about spacetimes of the form $\mathbb{R}^{3,1}\times$ a non-Kahler complex 3-fold. As with other flux compactifications, most — if not all — of the moduli get fixed. Unfortunately, these non-Kahler geometries are very hard to study, and not a lot is known. Keshav et al managed to find a particular example where, through a chain of string dualities, one can actually say quite a bit.

Scott gave two talks, one about his work with Giddings on making blackholes at the LHC. If, in a theory with large extra dimensions, the fundamental Planck scale is quite low (in the TeV range), we might be on the verge of reaching those energies — and creating microscopic blackholes — in the next generation of accelerators. Needless to say, the experimental signature of the production and subsequent evaporation (with a lifetime $\sim 10^{-23}$ sec.) of TeV-scale black holes would be quite dramatic.

Scott, however, put a more pessimistic spin on the subject. As you go to higher center-of-mass energies, the multiplicity of particles in the final state of the evaporation of a microscopic black holes goes up, and the average energy per particle goes down. In the end, all you get is soft junk, which tells you virtually nothing about short distance physics.

Repent! The end of Particle Physics is nigh!

He also talked about some work in progress with Dimopoulos on models of inflation in which the inflaton is a moduli field parameterizing the space of vacua of an $N=1$ supersymmetric gauge theory near an infrared fixed point. If the field has a large anomalous dimension, the inflaton potential can be very flat in the neighbourhood of the CFT point. It sounds like a really neat idea.

Posted by distler at November 14, 2003 12:36 AM

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