A
bstract
SU(2)
L
×
SU(2)
R
gauge symmetry requires three right-handed neutrinos (
N
i
), one of which,
N
1
, can be sufficiently stable to be dark matter. In the early universe,
W
R
exchange with ...the Standard Model thermal bath keeps the right-handed neutrinos in thermal equilibrium at high temperatures.
N
1
can make up all of dark matter if they freeze-out while relativistic and are mildly diluted by subsequent decays of a long-lived and heavier right-handed neutrino,
N
2
. We systematically study this parameter space, constraining the symmetry breaking scale of SU(2)
R
and the mass of
N
1
to a triangle in the (
v
R
, M
1
) plane, with
v
R
= (10
6
−
3
×
10
12
) GeV and
M
1
= (2 keV–1 MeV). Much of this triangle can be probed by signals of warm dark matter, especially if leptogenesis from
N
2
decay yields the observed baryon asymmetry. The minimal value of
v
R
is increased to 10
8
GeV for doublet breaking of SU(2)
R
, and further to 10
9
GeV if leptogenesis occurs via
N
2
decay, while the upper bound on
M
1
is reduced to 100 keV. In addition, there is a component of hot
N
1
dark matter resulting from the late decay of
N
2
→ N
1
ℓ
+
ℓ
−
that can be probed by future cosmic microwave background observations. Interestingly, the range of
v
R
allows both precision gauge coupling unification and the Higgs Parity understanding of the vanishing of the Standard Model Higgs quartic at scale
v
R
. Finally, we study freeze-in production of
N
1
dark matter via the
W
R
interaction, which allows a much wider range of (
v
R
,
M
1
).
Lepto-axiogenesis Co, Raymond T.; Fernandez, Nicolas; Ghalsasi, Akshay ...
The journal of high energy physics,
1/3, Letnik:
2021, Številka:
3
Journal Article
Recenzirano
Odprti dostop
A
bstract
We propose a baryogenenesis mechanism that uses a rotating condensate of a Peccei-Quinn (PQ) symmetry breaking field and the dimension-five operator that gives Majorana neutrino masses. The ...rotation induces charge asymmetries for the Higgs boson and for lepton chirality through sphaleron processes and Yukawa interactions. The dimension-five interaction transfers these asymmetries to the lepton asymmetry, which in turn is transferred into the baryon asymmetry through the electroweak sphaleron process. QCD axion dark matter can be simultaneously produced by dynamics of the same PQ field via kinetic misalignment or parametric resonance, favoring an axion decay constant
f
a
≲ 10
10
GeV, or by conventional misalignment and contributions from strings and domain walls with
f
a
∼ 10
11
GeV. The size of the baryon asymmetry is tied to the mass of the PQ field. In simple supersymmetric theories, it is independent of UV parameters and predicts the supersymmtry breaking mass scale to be
O
(10
−
10
4
) TeV, depending on the masses of the neutrinos and whether the condensate is thermalized during a radiation or matter dominated era. The high supersymmetry breaking mass scale may be free from cosmological and flavor/CP problems. We also construct a theory where TeV scale supersymmetry is possible. Parametric resonance may give warm axions, and the radial component of the PQ field may give signals in rare kaon decays from mixing with the Higgs and in dark radiation.
Axion misalignment driven to the hilltop Co, Raymond T.; Gonzalez, Eric; Harigaya, Keisuke
The journal of high energy physics,
05/2019, Letnik:
2019, Številka:
5
Journal Article
Recenzirano
Odprti dostop
A
bstract
The QCD axion serves as a well-motivated dark matter candidate and the misalignment mechanism is known to reproduce the observed abundance with a decay constant
f
a
≃
O
(10
12
) GeV for a ...misalignment angle
θ
mis
≃
O
(1). While
f
a
≪ 10
12
GeV is of great experimental interest, the misalignment mechanism requires the axion to be very close to the hilltop, i.e.
θ
mis
≃
π
. This particular choice of
θ
mis
has been understood as fine-tuning the initial condition. We offer a dynamical explanation for
θ
mis
≃
π
in a class of models. The axion dynamically relaxes to the minimum of the potential by virtue of an enhanced mass in the early universe. This minimum is subsequently converted to a hilltop because the CP phase of the theory shifts by
π
when one contribution becomes subdominant to another with an opposite sign. We demonstrate explicit and viable examples in supersymmetric models where the higher dimensional Higgs coupling with the inflaton naturally achieves both criteria. Associated phenomenology includes a strikingly sharp prediction of 3 × 10
9
GeV ≲
f
a
≲ 10
10
GeV and the absence of isocurvature perturbation.
The domain wall problem of the Peccei–Quinn mechanism can be solved if the Peccei–Quinn symmetry is explicitly broken by a small amount. Domain walls decay into axions, which may account for dark ...matter of the universe. This scheme is however strongly constrained by overproduction of axions unless the phase of the explicit breaking term is tuned. We investigate the case where the universe is matter-dominated around the temperature of the MeV scale and domain walls decay during this matter dominated epoch. We show how the viable parameter space is expanded.
A
bstract
The vanishing of the Higgs quartic coupling at a high energy scale may be explained by Intermediate Scale Supersymmetry, where supersymmetry breaks at (10
9
-10
12
) GeV. The possible range ...of supersymmetry breaking scales can be narrowed down by precise measurements of the top quark mass and the strong coupling constant. On the other hand, nuclear recoil experiments can probe Higgsino or sneutrino dark matter up to a mass of 10
12
GeV. We derive the correlation between the dark matter mass and precision measurements of standard model parameters, including supersymmetric threshold corrections. The dark matter mass is bounded from above as a function of the top quark mass and the strong coupling constant. The top quark mass and the strong coupling constant are bounded from above and below respectively for a given dark matter mass. We also discuss how the observed dark matter abundance can be explained by freeze-out or freeze-in during a matter-dominated era after inflation, with the inflaton condensate being dissipated by thermal effects.
Axion misalignment driven to the bottom Co, Raymond T.; Gonzalez, Eric; Harigaya, Keisuke
The journal of high energy physics,
05/2019, Letnik:
2019, Številka:
5
Journal Article
Recenzirano
Odprti dostop
A
bstract
Several theoretical motivations point to ultralight QCD axions with large decay constants
f
a
≃
O
10
16
−
10
17
GeV
, to which experimental proposals are dedicated. This regime is known to ...face the problem of overproduction of axion dark matter from the misalignment mechanism unless the misalignment angle
θ
mis
is as small as
O
10
−
3
−
10
−
4
, which is generally considered a fine-tuning problem. We investigate a dynamical explanation for a small
θ
mis
. The axion mass arises from strong dynamics and may be sufficiently enhanced by early dynamics so as to overcome Hubble friction and drive the field value to the bottom of the potential long before the QCD phase transition. Together with an approximate CP symmetry in the theory, this minimum is very closely related to today’s value and thus
θ
mis
can automatically be well under unity. Owing to such efficient relaxation, the isocurvature perturbations are essentially damped. As an existence proof, using supersymmetric theories we illustrate that the Higgs coupling with the inflaton energy can successfully achieve this axion damping in a consistent inflationary cosmology.
Higgs Parity grand unification Hall, Lawrence J.; Harigaya, Keisuke
The journal of high energy physics,
11/2019, Letnik:
2019, Številka:
11
Journal Article
Recenzirano
Odprti dostop
A
bstract
The vanishing of the Higgs quartic coupling of the Standard Model at high energies may be explained by spontaneous breaking of Higgs Parity. Taking Higgs Parity to originate from the ...Left-Right symmetry of the SO(10) gauge group, leads to a new scheme for precision gauge coupling unification that is consistent with proton decay. We compute the relevant running of couplings and threshold corrections to allow a precise correlation among Standard Model parameters. The scheme has a built-in solution for obtaining a realistic value for
m
b
/m
τ
, which further improves the precision from gauge coupling unification, allowing the QCD coupling constant to be predicted to the level of 1% or, alternatively, the top quark mass to 0.2%. Future measurements of these parameters may significantly constrain the detailed structure of the theory. We also study an SO(10) embedding of quark and lepton masses, showing how large neutrino mixing is compatible with small quark mixing, and predict a normal neutrino mass hierarchy. The strong CP problem may be explained by combining Higgs Parity with space-time parity.
A
bstract
Axion-like particles (ALPs) can be naturally lighter than the electroweak scale. We consider an ALP that couples to the Standard Model Higgs to achieve the strong first-order electroweak ...phase transition. We discuss the two-field dynamics of the phase transition and the associated computation in detail and identify the viable parameter space. The ALP mass can be from the MeV to GeV scale. Baryon asymmetry can be explained by local baryogenesis without violating the current electron and atom electric dipole moment bound in most of the viable parameter space. The viable parameter space can be probed through Higgs exotic decay, rare kaon decay, the electron and atomic electric dipole moment, and the effective number of neutrinos in the cosmic microwave background in the future. The gravitational-wave signal is too weak to be detected.
A
bstract
We consider the transfer of a U(1) charge density between Bose-Einstein condensates of complex scalar fields coupled to a thermal bath, focusing on the case of a homogeneous Affleck-Dine ...field transmitting the charge stored in its angular motion to an axion field. We demonstrate that in the absence of additional symmetries this charge transfer, aided by cosmic expansion as well as the thermal effective potential of the Affleck-Dine field, can be very efficient. The charge redistribution between the scalar fields becomes possible if the interactions with the thermal bath break the original U(1)
×
U(1) symmetry down to a single U(1) symmetry; the charge distribution between the two fields is then determined by minimizing the free energy. We discuss implications for cosmological setups involving complex scalars, with applications to axion dark matter, baryogenesis, kination domination, and gravitational wave production.
PDF
