Mon, 02 Feb 2015

12:00 - 13:00
Fisher Room of NAPL

BRST Cohomology, Extraordinary Invariants and the Zen Splitting of SUSY

John Dixon
(visiting Oxford)
Abstract

The chiral scalar superfield has interesting BRST cohomology, but the relevant cohomology objects all  have spinor indices. So they cannot occur in an action. They need to be coupled to a chiral dotted spinor superfield. Until now, this has been very problematic, since no sensible action for a chiral dotted spinor superfield was known.  The most obvious such action contains higher derivatives and tachyons.

Now,  a sensible  action has been found. When coupled to the cohomology, this action removes the supersymmetry charge from the theory while maintaining the rigidity and power of supersymmetry.The simplest example of this phenomenon has exactly the fermion content of the Leptons or the Quarks.  The mechanism has the potential to get around the cosmological constant problem, and also the problem of the sum rules of spontaneously broken supersymmetry.

Thu, 25 Oct 2007
16:15
Fisher Room of NAPL

New Searches for sub-gravitational forces

Jay Wacker
(SLAC)
Abstract

I will describe how atom interferometry can be used to set limits on beyond the Standard Model forces.

Thu, 14 Jun 2007
16:15
Fisher Room of NAPL

Using Spin to Distinguish Models at the LHC

Jennie Smillie
(Cambridge)
Abstract
 

If new particles are produced at the LHC, it is vital that we can extract as much information as possible from them about the underlying theory.  I will discuss some recent work on extracting spin information from invariant mass distributions of new particles.  I will then introduce the Kullback-Leibler method of quantifying our ability to distinguish different scenarios.  

Thu, 07 Jun 2007
16:15
Fisher Room of NAPL

F-term hybrid inflation followed by modular inflation

Constantinos Pallis
(Manchester)
Abstract
 

We consider two-stage inflationary models in which a superheavy scale F-term hybrid inflation is followed by an intermediate scale modular inflation. We confront these models with the restrictions on the power spectrum of density perturbations P_R and the spectral index n_s from the recent data within the power-law cosmological model with cold dark matter and a cosmological constant. We show that these restrictions can be met provided that the number of e-foldings N_HI* of the pivot scale k*=0.002/Mpc during hybrid inflation is appropriately restricted. The additional e-foldings required for solving the horizon and flatness problems can be naturally generated by the subsequent modular inflation realized by a string axion.
   

Thu, 31 May 2007
16:15
Fisher Room of NAPL

TBA

Jeff Forshaw
(Manchester)
Thu, 24 May 2007
16:15
Fisher Room of NAPL

TBA

Francesco Riva
(Oxford)
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