Download Common problem against B and L genesis and its possible resolution

Common problem against B and L genesis and
its possible resolution
M. Yoshimura
• Introduction
• 3 conditions for B asymmetry generation
• Sources of B non-conservation at finite T
GUT, electroweak
・ Scenario of original B-genesis
・ Thermal L-genesis and general remarks
・ Possible nightmare: gravitino problem
・ Way out
• Conclusion
Why are we (as a form of matter) here ?
• Despite that the law of microphysics is almost
matter-antimatter symmetric, and
• Despite that in the early universe antimatter
production is energetically possible and
equilibrium must have been established by the
laws of gravity and thermodynamics, and
• Despite that matter-antimatter pair annihilation is
very effective
Mystery of our existence:
Generation of B-asymmetry
• Key quantity
 nB 
 
 n after annihilation
Observation
 BB
 O 1  

 B  B before annihilation
nB
n
10

 O 10  6.1  0.3(WMAP )
imply 1 excess of B out of 1010 pairs
Is imbalance for matter a hint on some symmetry violation ?
Absence of antimatter and problem with
symmetric cosmology
ñ
•
10
Observational evidence against symmetric cosmology
He
 106
He
ñ
near earth
Annual Variation of P /P Ratio
-3
Y. Asaoka et al., Phys. Rev. Lett., in press.
BESS(97)
BESS(99)
BESS(00)
/
tio
a
r
P
P
10
p/p Ratio
-4
low energy p spectrum
No evidence of

from
N  N  
0
10
-5
Bieber et al, 1999
10, ( ) ~ 1997
solar min. at positive phase
70, ( ) ~ 1999
solar max. at positive phase
•
70, ( ) ~ 2000
Theoretical problem with B-symmetric cosmology
nB nB
O[100]


n n mN m pl  v
much smaller than observed
solar max. at negative phase
10
 10
18
NN
10 10
No working model of domain separation
-6
10
-1
mN
@T 
50
1
10
Kinetic Energy (GeV)
How to produce the asymmetry：
3 conditions
in the early universe
Necessary ingredients
B
CP
out of equilibrium
Need of arrow of time
without suppression of inverse process,
B =  B    B   0
Sources of B nonconservation
• GUT
• Electroweak at high T: leading to L to B
conversion @ 200GeV  T  1012 GeV
• SUSY （Affleck-Dine mechanism)
Electroweak baryon nonconservation
Electroweak damping
Gauge and Higgs
Electroweak baryon noncnoservation
suppressed at T=0 by
e 137
enhanced at finite T by barrier crossing
Can destroy preexisting B and L while keeping B-L
Mechanism due to level crossing of fermions caused by nontrivial gauge
and higgs configuration of sphaleron and alike
Baryogenesis in standard model
• B
unsuppressed
  o[1]W T
4
e
 M sp / T
at finite T
@T
M sp  O[TeV ]
• CP
KM phase
• Out of equilibrium: 1st order phase transition via
bubble formation
Difficulties of EW B-genesis
・Out of equilibrium condition requires a large
radiative correction to the Higgs potential to
obtain a strong 1st order phase transition, but
experimental Higgs mass bound > 115 GeV
excludes this possibility
• Magnitude too small due to KM phase alone
nB
 o[1021  1025 ]
n
Electroweak redistribution of B and L
8ng  4nH
28

B  a  ( B  L), a 
22ng  13nH 79
200GeV  T  1012 GeV
For standard model of 3 generations
B-L conserved and never washed out.
Original B-generation does not survive, but
redistributed
Opens a new possibility of L-genesis
GUT generation of B with B-L
nonconservation
B  0
@ GUT
e.g.
H X  qq, ql
and its conjugate
• SO(10) model is OK with constraint on neutrino
masses
• SU(5) is excluded
Out of equilibrium condition:
case of heavy particle decay
X  qq, ql
• One way decay, no inverse decay
H  (  mX )
1.6 NT 2
H 
m pl
@ T  mX
Otherwise, Boltzmann suppression by
Typically leading to
nX  exp(mX / T )
mX  O[0.01] mpl  10 GeV
15
Need for high unification scale
Reheating after inflation
TRH  mX
In GUT view,
• We are here,
because matter that makes up us is
ultimately unstable !
But,
lifetime of proton typically
30
10 years
age of universe
L genesis and B conversion
• L-genesis of amount L
first and
electroweak conversion into B, via
28
B   L
79
For standard model of 3 generations
Interesting in view of possible connection to
observed neutrino masses
Neutrino physics
Cosmic rays
• Neutrino oscillation
Neutrinos
Neutrinos
Upward
 Evidence of
neutrino mass!
Downward
Cosmic rays
Likely mechanism of small neutrino
mass generation
• Seesaw mechanism Heavy Majorana type of
masses of neutrino partner, independent of standard
theory of particle physics, generates a tiny lefthanded neutrino masses and mixing a la
Neutrino mass via seesaw
m

mq , l
2
M new physics
• Necessarily violates lepton number conservation
Thermal L genesis
Fukugita-Yanagida
• Minimal extention of standard model with seesaw
Right-handed Majorana decay
 R  lH , l H
CP asymmetry with neutrino mass matrix
m  mD M m
†
M1 m
3 M1 Im(mD m mD *)11
 O[ 2  ]
1 
†
2
v
16 v
(mD mD )11
M1

M2
= CP phase
M3
1
For 3 R-Majoranas
T
D
Great impacts on neutrino masses
and thermal history of universe
With hierarchy of masses, dependence on 3 parameters Giudice et al
1 , M 1 ,
(hh† )11
m 
M1
• Connection to neutrino masses
heaviest neutrino (WMAP 0.23eV)
m3  0.13eV
M  5 108 GeV lightest R-neutrino
1
• Reheat temperature
TRH  M1
Delicacy of CP： Quantum interference
Baryon excess from a pair of particle and
antiparticle process, e.g.
X X
g1 f1  g 2 f 2    
2
 g
*
1
f1  g 2 f 2    
*
 4 Im( g1 g 2 ) Im( f1 f 2 )    
*
Im( g1 g2 )  0
*
Im( f1 f 2 )  0
*
*
CP violation
Rescattering phase
Interference computed by Landau-Cutkovsky rule
q
＝
2
Gravitino problem: a possible nightmare
both for GUT B- and L-genesis
• Superpartner of graviton
m3/ 2  O[TeV ]
mass
3
m
m
lifetime
  O[ 3/ 2 ]  O[(105 sec)1 ( 3/ 2 )3 ]
m pl
2
TeV
• Usual estimate of gravitino abundance and constraint
from nucleosynthesis, including hadronic decay
n3 / 2
 2 TRH
 O[10 ]
s
m pl
TRH  106  108 GeV
Possible to produce heavy
NR , H X
？
My favorite scenario for resolution
• Both baryon asymmetry and gravitino
abundance was diluted before
thermalization period after its violent, initial
production stage during preheating
Preheating: new understanding of entropy
production before thermalization stage
• Non-perturbative effect of parametric
resonance, leading to
Complicated high energy phase of reheating,
i.e. preheating、
may be used for dilution of gravitino
bundance
Common to copious non-thermal production
of R-Majorana neutrino for L-genesis
Theory of particle production with chaotic
potential
• Inflaton field oscillation given by
 (t )   0 cos(m t ) (spatially homogeneous, periodic)
0
m pl m  1013 GeV
Interaction by
g 
2

Producing a pair of
particles
.
For each momentum
mode of massive particle
a .
2
2
k  3 k  (k  m  g0 cos(m t ))k  0
a
2
g0
k  g0

1
..
h
m
2
m
2
Non-perturbative effect of parametric
resonance, producing large mass particles
・n-th band contribution like
  
n
• Large mass production possible if
with large n
m
n
 m  m
2
2
• Perturbative Born decay;
from E-conservation
m 
m
2
Preheating stage and gravitino abundance
• e.g. B-generation during preheating and
gravitino abundance lowed by perturbative estimate is possible
Summary on B – L genesis
• (B-L) genesis is a great hint on physics beyond
the standard model, linking the micro and the
macro worlds
• B-genesis still alive, waiting for nucleon decay
• L-genesis interesting due to its possible
connection to the neutrino sector and lepton
flavor violation
• Watch out gravitino overproduction
• Some new idea necessary for relation to low
energy CP violation in K and B systems