# Stephon Alexander : Observing the string: The cosmic matter-antimatter asymmetry from string theory and the universality of the Green-Schwarz mechanism

One of the most fundamental unresolved questions in particle physics and cosmology is the origin of the cosmic baryon asymmerty, a necessary ingredient for galaxy formation. There are three known conditions for baryogesis, the Sakharov conditions: (1) Baryon number violation; (2) CP, C violation; (3) (1) & (2) must simulatneously occur out of equilibrium with the rest of the universe. Over the last 25 years it has been a challenge to realize these conditions and the precise number (n/s \sim 6.04 \times 10^{-10}) for baryon asymmetry within the framework of the standard model of particle physics and cosmology. In this seminar we show that the baryon asymmetry can be generated, unifying all three Sakharov conditions, during the epoch of cosmic inflation. The Sakharov conditions are realized in one physical proccess, the quantum generation of elliptically polarized gravitons. We further, show that this mechanism is realized concretely and in a compactification independent manner in superstring theory. We construct a Heterotic model of this inflationary baryogenesis mechanism and observationally constrain(postdict) the string length scale from a cosmological observable. Key to this result is the universality of the model independent axion and the Green-Schwarz mechanism. We report on future work w.r.t a heterotic version of the KKLT mechanism via. geometric transistion.

**Category**: String Theory**Duration**: 01:09:49**Date**: October 14, 2004 at 2:45 PM**Views**: 28-
**Tags:**seminar, String Theory Seminar

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