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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
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SEQUENCE:0
UID:UW-Physics-Event-1635
DTSTART:20091210T220000Z
DURATION:PT1H0M0S
DTSTAMP:20260428T091712Z
LAST-MODIFIED:20091130T182435Z
LOCATION:5310 Chamberlin
SUMMARY:Dark Energy and Dark Matter from Gravitational Symmetry Breaki
 ng\, NPAC (Nuclear/Particle/Astro/Cosmo) Forum\, Andre Fuzfa\, GAMASCO
 \, University of Namur (FUNDP)  and  LUTH\, Observatory of Paris.
DESCRIPTION:Coupling dark matter (DM) to dark energy (DE) is one of th
 e most promising way to build a unified description of the invisible s
 ector of cosmology. However\, such DM-DE couplings make the mass of th
 e DM particles varying\, therefore breaking the universality of free f
 all (Galileo's equivalence principle). Doing so\, the strong equivalen
 ce principle\, stating the universality of gravitational binding energ
 y\, does not hold anymore\, particularly where DM is profuse like in t
 he large-scale universe. Such mass-varying DM particles therefore cons
 titute an Abnormally Weighting type of Energy (AWE Hypothesis) and the
 ir cosmological abundance induces modifications of gravity on large-sc
 ales\, modifications that can explain cosmic acceleration. I will pres
 ent here how this AWE hypothesis can be naturally achieved in terms of
  the explicit symmetry breaking of a global U(1) symmetry in particle 
 physics. In this context\, the U(1)-charged complex scalar usually spl
 its into a mass-varying pseudo-Nambu-Goldstone boson (axion-like DM pa
 rticles) while the vacuum expectation value of the complex scalar has 
 to be stabilised\, usually through the use of the potential (spontaneo
 us symmetry breaking mechanism). We show here that the cosmological re
 laxation toward the equivalence principle can play this crucial stabil
 ising role and explain in addition the observed cosmic acceleration.  
 Stabilisation of the new scalar is achieved through non-minimal gravit
 ational couplings. We will show several remarkable cosmological predic
 tions of this idea and emphasize some interesting applications on neut
 rino physics for the gravitational symmetry breaking of lepton number 
 symmetry.
URL:https://www.physics.wisc.edu/events/?id=1635
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