000168646 001__ 168646
000168646 005__ 20190509132410.0
000168646 0247_ $$2doi$$a10.5075/epfl-thesis-5192
000168646 02470 $$2urn$$aurn:nbn:ch:bel-epfl-thesis5192-5
000168646 02471 $$2nebis$$a6575820
000168646 037__ $$aTHESIS
000168646 041__ $$aeng
000168646 088__ $$a5192
000168646 245__ $$aVacuum Stability in Supersymmetric Effective Theories
000168646 269__ $$a2011
000168646 260__ $$bEPFL$$c2011$$aLausanne
000168646 300__ $$a156
000168646 336__ $$aTheses
000168646 520__ $$aThe main topics discussed in this thesis are  supersymmetric low-energy effective theories and  metastability conditions in generic non-renormalizable models  with global and local supersymmetry. In the first part we discuss the conditions under which  the low-energy expansion in space-time derivatives preserves  supersymmetry implying that heavy multiplets can be more  efficiently integrated out directly at the superfield level.  These conditions translate into the requirements that also  fermions and auxiliary fields should be small compared to the  heavy mass scale. They apply not only to the matter sector,  but also to the gravitational one if present, and imply in  that case that the gravitino mass should be small. We finally  give a simple prescription to integrate out heavy chiral and  vector superfields consisting respectively in imposing  stationarity of the superpotential and of the Kähler  potential; the procedure holds in the same form both for  global and local supersymmetry. In the second part we study general criteria for the  existence of metastable vacua which break global  supersymmetry in models with local gauge symmetries. In  particular we present a strategy to define an absolute upper  bound on the mass of the lightest scalar field which depends  on the geometrical properties of the Kähler target  manifold. This bound can be saturated by properly tuning the  superpotential and its positivity therefore represents a  necessary and sufficient condition for the existence of  metastable vacua. It is derived by looking at the subspace of  all those directions in field space for which an arbitrary  supersymmetric mass term is not allowed and scalar masses are  controlled by supersymmetry-breaking splitting effects. This  subspace includes not only the direction of supersymmetry  breaking, but also the directions of gauge symmetry breaking  and the lightest scalar is in general a linear combination of  fields spanning all these directions. Our purpose is to show  that the largest value for the lightest mass is in general  achieved when the lightest scalar is a combination of the  Goldstone and the Goldstino partners. We conclude by computing the effects induced by the  integration of heavy multiplets on the light masses. In  particular we focus on the sGoldstino partners and we show  that heavy chiral multiplets induce a negative  level-repulsion effect that tends to compromise vacuum  stability, whereas heavy vector multiplets in general induce  a positive-definite contribution. Our results find application in the context of  string-inspired supergravity models, where metastability  conditions can be used to discriminate among different  compactification scenarios and supersymmetric effective  theories can be used to face the problem of moduli  stabilization.
000168646 6531_ $$aStandard Model
000168646 6531_ $$aSupersymmetry Breaking
000168646 6531_ $$aHidden Sector
000168646 6531_ $$aModuli
000168646 6531_ $$aSupergravity
000168646 6531_ $$aEffective Field Theories
000168646 6531_ $$aVacuum Stability
000168646 700__ $$0244580$$g182167$$aBrizi, Leonardo
000168646 720_2 $$aScrucca, Claudio$$edir.$$g181759$$0244581
000168646 8564_ $$uhttps://infoscience.epfl.ch/record/168646/files/EPFL_TH5192.pdf$$zTexte intégral / Full text$$s1094462$$yTexte intégral / Full text
000168646 909C0 $$xU11777$$0252314$$pGR-SC
000168646 909CO $$pthesis-bn2018$$pDOI$$pSB$$ooai:infoscience.tind.io:168646$$qDOI2$$qGLOBAL_SET$$pthesis
000168646 918__ $$dEDPY$$cITP$$aSB
000168646 919__ $$aGR-SC
000168646 920__ $$b2011
000168646 970__ $$a5192/THESES
000168646 973__ $$sPUBLISHED$$aEPFL
000168646 980__ $$aTHESIS