The Origin of the Matter-
Will we ever know?
SLAC Conference on Heavy Flavor Physics
at High Luminosity e+e- Colliders
• From Nucleosynthesis:
WB h2 = 0.0214§ 0.002
• From CMBR:
WBh2 = 0.0224§ 0.0009
• Violation of Baryon Number at the level of
the fundamental laws
• An Arrow of Time
• CP Violation
u e+ e+
u X d^c
[Cline,Joyce and Kainulainen, 1998]
Scalar in condensate
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
• 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.