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Informal Pizza SeminarWhy the Cosmological Constant May Be Small but NonzeroCliff BurgessMcGillI'll argue that an effective four-dimensional cosmological constant can naturally be of order 1/r4 in six-dimensional supergravity compactified on two dimensions having radius r, with supersymmetry broken on non-supersymmetric 3-branes (on one of which we live). In the scenario where the extra dimensions are sub-millimeter in size, this is the correct size to describe the recently-discovered dark energy. This mechanism therefore predicts a connection between the observed size of the cosmological constant, and potentially observable effects in sub-millimeter tests of gravity and at the Large Hadron Collider. I'll argue that quantum corrections to this small cosmological constant also remain small, if the branes have specific properties, and that the usual obstacles to this are evaded because the low-energy theory is six-dimensional right down to the cosmological constant scale. Finally, I'll present a potential realization of the mechanism in which these claims can be tested.
Tuesday, May 6th 2003, 13:00
Ernest Rutherford Physics Building, room 326 |