Gravitino or axino dark matter with reheat temperature as high as 1016 GeV
Received: December
Gravitino or axino dark matter with reheat temperature as high as 10
G 0 1 3 7
V 0 1 3 7
Raymond T. Co 0 1 3 4 6 7
Francesco D'Eramo 0 1 2 3 5 7
Lawrence J. Hall 0 1 3 4 6 7
0 1156 High Street, Santa Cruz, CA 95064 , U.S.A
1 1 Cyclotron Rd. , Berkeley, CA 94720 , U.S.A
2 Santa Cruz Institute for Particle Physics
3 366 LeConte Hall MC 7300 , Berkeley, CA 94720 , U.S.A
4 Theoretical Physics Group, Lawrence Berkeley National Laboratory
5 Department of Physics, University of California Santa Cruz
6 Berkeley Center for Theoretical Physics, Department of Physics, University of California
7 Open Access , c The Authors
A new scheme for lightest supersymmetric particle (LSP) dark matter is introduced and studied in theories of TeV supersymmetry with a QCD axion, a, and a high reheat temperature after in ation, TR. A large overproduction of axinos (a~) and gravitinos (G~) from scattering at TR, and from freeze-in at the TeV scale, is diluted by the late decay of a saxion condensate that arises from in ation. The two lightest superpartners are ~a, with mass of order the TeV scale, and G~ with mass m3=2 anywhere between the keV and TeV scales, depending on the mediation scale of supersymmetry breaking. Dark matter contains both warm and cold components: for G~ LSP the warm component arises from a~ ! G~a, while for a~ LSP the warm component arises from G~ ! a~a. The free-streaming scale for the warm component is predicted to be of order 1 Mpc (and independent of m3=2 in the case of G~ LSP). TR can be as high as 1016 GeV, for any value of m3=2, solving the gravitino problem. The PQ symmetry breaking scale VPQ depends on TR and m3=2 and can be anywhere in the range (1010 1016) GeV. Detailed predictions are made for the lifetime of the neutralino LOSP decaying to a~+h=Z and G~ +h=Z= , which is in the range of (10 1 over much of parameter space. For an axion misalignment angle of order unity, the axion contribution to dark matter is sub-dominant, except when VPQ approaches 1016 GeV.
Contents
1 Introduction
2 Saxion cosmology 2.1 2.2 2.3
3 Axino and gravitino production
Freeze-in production of axinos
UV production of axinos
UV production of gravitinos
3.4 Freeze-in production of gravitinos
4 Axino and gravitino as the lightest superpartners Warm dark matter from NLSP decays Displaced signals at colliders Axion dark radiation
5 Results for high scale or \gravity" mediation
High reheat temperature after in ation: TR & 1010 GeV
Low reheat temperature after in ation: TR . 1010 GeV
Field equations
The DFSZ0 theory
5.2 The DFSZ+ theory
The DFSZ0 theory
6.2 The DFSZ+ theory
6 Results for low scale or \gauge" mediation A Axion supermultiplet interactions A.1 Color anomaly A.2 Supersymmetric interactions
A.3 SUSY breaking interactions
B Decay widths
B.1 Saxion decays
B.2 Neutralino and chargino decays to axinos
B.3 Gravitino decays
B.4 Axino and neutralino decays to gravitinos
C Free streaming of warm DM component
Introduction
CP -violating phase
to zero. In this case dark matter could be axions produced by the
misalignment mechanism, with VPQ of order 1012 GeV a motivated possibility.
axions. The axion, a, must be promoted to a super eld
A =
and the saxion, s, and the axino, a~, both play central roles in cosmology.
the PQ symmetry forbids the
term of the minimal supersymmetric standard model
(MSSM). At the scale VPQ, PQ breaking induces the
axion supermultiplet with the MSSM Higgs super elds
term as well as a coupling of the
WDFSZ =
HuHd + q
A HuHd + : : : ;
VPQ
In order to make this distinction sharper, we de ne two di erent types of theories:
source for axino production is the IR dominated freeze-in;
o quarks and gluons.
appendix A.
m3/2 = 100 GeV
m3/2 = 10 GeV
m3/2 = 1 GeV
m3/2 = 100 MeV
m3/2 = 100 GeV
m3/2 = 10 GeV
m3/2 = 1 GeV
m3/2 = 100 MeV
VPQ (GeV)
VPQ (GeV)
= 1 TeV,
= 2 and q
. For UV production in
portions of the lines refer to a freeze-in contribution smaller (larger) than 50%.
but we nd this contribution sub-dominant to the ones mentioned above.
misalignment angle is selected by an anthropic requirement.
in ation, and not restoring it afterwards. We de ne the saxion
eld so that today the
term, the vacuum value sI is either VPQ or of order the cuto of the eld theory, M
for dark matter:
VPQ [18, 19].2 If sI & 1013 GeV or sI
M , this saxion condensate comes to dominates
only for the restricted case of sI
VPQ . 1013 GeV, when the saxion condensate never
1012 GeV. However, as we have already mentioned, this case of low VPQ has a serious
MD era that has important consequences for dark matter abundance.
In KSVZ [20, 21] axion theories the MSSM
term is not forbidden by PQ symmetry
very low reheat temperature of the saxion3 TRs; for example, TRs
GeV{MeV for VPQ
1016) GeV, respectively. The decay of the saxion condensate has crucial implications
together [26].
For VPQ > 1013 GeV, the entropy is released after the axion condensate starts to
value of fa needed for axion dark matt (...truncated)