The Origin of the Matter-Antimatter Asymmetry

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					The Origin of the Matter-
 Antimatter Asymmetry:
       Will we ever know?




       Michael Dine
       SLAC Conference on Heavy Flavor Physics
       at High Luminosity e+e- Colliders
                             May, 2003
          The Asymmetry
• From Nucleosynthesis:
  WB h2 = 0.0214§ 0.002
• From CMBR:
  WBh2 = 0.0224§ 0.0009
        Sakharov Conditons
• Violation of Baryon Number at the level of
  the fundamental laws
• An Arrow of Time
• CP Violation
u       e+ e+
    X
u   X     d^c
                po
d
X

    X
        MW=0



MW=gf
[Cline,Joyce and Kainulainen, 1998]
    h
N
N

        l l
VV


         f
     f
Scalar in condensate
         PROSPECTS
   Cosmology and Microphysics
• Nucleosynthesis: we can calculate the dark matter
  density from our knowledge of microphysics.
• Dark Matter: We might calculate the dark matter
  density in the future if supersymmetry is
  discovered, and the properties of superparticles
  measured (esp. masses – linear collider); or if we
  discover axions. Both scenarios require
  (plausible) assumptions about the early universe.
• Inflation: probably requires theoretical as well as
  observational input (string theory?).
Baryogenesis: we have narrowed
     the possibilities, but:
• With neutrino mass, we may have encountered a
  basic clue to the origin of the matter-antimatter
  asymmetry. Measurements plus theoretical
  developments will be necessary to a calculation of
  the asymmetry.
• Discovery of supersymmetry would open up new
  possibilities (coherent production, electroweak
  baryogenesis). But theory as well as experiment
  will be necessary.
• In either case, further theoretical progress will
  surely require more theoretical input on the
  questions of flavor and CP violation.