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Event Number 3304
Friday, February 28th, 2014
 Theory Seminar (High Energy/Cosmology)
 Pure Gravity Mediation
 Time: 2:00 pm
 Place: 5280 Chamberlin Hall
 Speaker: Jason Evans, University of Minnesota
 Abstract: If low energy supersymmetry is realized in nature, the apparent discovery of a Higgs boson with mass around 125 GeV suggests a supersymmetric mass spectrum in the TeV or multiTeV range. MultiTeV scalar masses are a necessary component of supersymmetric models with pure gravity mediation or in any model with strong moduli stabilization. The simplest model of pure gravity mediation contains only two free parameters: the gravitino mass and $tan beta$. Scalar masses are universal at some high energy renormalization scale and gaugino masses are determined through anomalies and depend on the gravitino mass and the gauge couplings. This theory requires a relatively large graviton mass (m_{3/2} gtrsim 300 TeV) and a limited range in tan beta simeq 1.72.5. By allowing for nonunversalities in the Higgs soft masses, the allowed range in tan beta is greatly increased which then permits smallers values of m_{3/2} and makes detection of the gluino at the LHC possible. Furthermore, if one adopts a noscale or partial noscale structure for the K"ahler manifold, sfermion masses may vanish at the tree level. It is usually assumed that the leading order anomaly mediated contribution to scalar masses appears at 2loops. However, there are at least two possible sources for 1loop scalar masses. These may arise if PauliVillars fields are introduced as messengers of supersymmetry breaking. We consider the consequences of a spectrum in which the scalar masses associated with the third generation are heavy (order $m_{3/2}$) with 1loop scalar masses for the first two generations. A similar spectrum is expected to arise in GUT models based on $E_7/SO(10)$ where the first two generations of scalars act as pseudoNambuGoldstone bosons. Explicit breaking of this symmetry by the gauge couplings then generates oneloop masses for the first two generations. In particular, we show that it may be possible to reconcile the $g_mu  2$ discrepancy with potentially observable scalars and gauginos at the LHC.
 Host: Jordi SalvadÃ³ Serra
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