A
bstract
Space-time parity can solve the strong CP problem and introduces a spontaneously broken SU(2)
R
gauge symmetry. We investigate the possibility of baryogenesis from a first-order SU(2)
R
...phase transition similar to electroweak baryogenesis. We consider a model with the minimal Higgs content, for which the strong CP problem is indeed solved without introducing extra symmetry beyond parity. Although the parity symmetry seems to forbid the SU(2)
R
anomaly of the
B
−
L
symmetry, the structure of the fermion masses can allow for the SU(2)
R
sphaleron process to produce non-zero
B
−
L
asymmetry of Standard Model particles so that the wash out by the SU(2)
L
sphaleron process is avoided. The setup predicts a new hyper-charged fermion whose mass is correlated with the SU(2)
R
symmetry breaking scale and hence with the SU(2)
R
gauge boson mass, and depending on the origin of CP violation, with an electron electric dipole moment. In a setup where CP violation and the first-order phase transition are assisted by a singlet scalar field, the singlet can be searched for at future colliders.
A
bstract
We propose a framework where a phase transition associated with a gauge symmetry breaking that occurs (not far) above the electroweak scale sets a stage for baryogenesis similar to the ...electroweak baryogenesis in the Standard Model. A concrete realization utilizes the breaking of SU(2)
R
×
U(1)
X
→
U(1)
Y
. New chiral fermions charged under the extended gauge symmetry have nonzero lepton numbers, which makes the
B − L
symmetry anomalous. The new lepton sector contains a large flavor-dependent CP violation, similar to the Cabibbo-Kobayashi-Maskawa phase, without inducing sizable electric dipole moments of the Standard Model particles. A bubble wall dynamics associated with the first-order phase transition and SU(2)
R
sphaleron processes generate a lepton asymmetry, which is transferred into a baryon asymmetry via the ordinary electroweak sphaleron process. Unlike the Standard Model electroweak baryogenesis, the new phase transition can be of the strong first order and the new CP violation is not significantly suppressed by Yukawa couplings, so that the observed asymmetry can be produced. The model can be probed by collider searches for new particles and the observation of gravitational waves. One of the new leptons becomes a dark matter candidate. The model can be also embedded into a left-right symmetric theory to solve the strong CP problem.
A
bstract
Rotations of an axion field in field space provide a natural origin for an era of kination domination, where the energy density is dominated by the kinetic term of the axion field, preceded ...by an early era of matter domination. Remarkably, no entropy is produced at the end of matter domination and hence these eras of matter and kination domination may occur even after Big Bang Nucleosynthesis. We derive constraints on these eras from both the cosmic microwave background and Big Bang Nucleosynthesis. We investigate how this cosmological scenario affects the spectrum of possible primordial gravitational waves and find that the spectrum features a triangular peak. We discuss how future observations of gravitational waves can probe the viable parameter space, including regions that produce axion dark matter by the kinetic misalignment mechanism or the baryon asymmetry by axiogenesis. For QCD axion dark matter produced by the kinetic misalignment mechanism, a modification to the inflationary gravitational wave spectrum occurs above 0.01 Hz and, for high values of the energy scale of inflation, the prospects for discovery are good. We briefly comment on implications for structure formation of the universe.
A
bstract
We consider two copies of the Standard Model, interchanged by an exact parity symmetry,
P
. The observed fermion mass hierarchy is described by suppression factors
ϵ
n
i
for charged fermion
...i
, as can arise in Froggatt-Nielsen and extra-dimensional theories of flavor. The corresponding flavor factors in the mirror sector are
ϵ
′
n
i
, so that spontaneous breaking of the parity
P
arises from a single parameter ϵ′/ϵ, yielding a tightly constrained version of Minimal Mirror Twin Higgs, introduced in our previous paper. Models are studied for simple values of
n
i
, including in particular one with SU(5)-compatibility, that describe the observed fermion mass hierarchy. The entire mirror quark and charged lepton spectrum is broadly predicted in terms of ϵ′/ϵ, as are the mirror QCD scale and the decoupling temperature between the two sectors. Helium-, hydrogen- and neutron-like mirror dark matter candidates are constrained by self-scattering and relic ionization. In each case, the allowed parameter space can be fully probed by proposed direct detection experiments. Correlated predictions are made as well for the Higgs signal strength and the amount of dark radiation.
Higgs Parity, strong CP and dark matter Dunsky, David; Hall, Lawrence J.; Harigaya, Keisuke
The journal of high energy physics,
07/2019, Letnik:
2019, Številka:
7
Journal Article
Recenzirano
Odprti dostop
A
bstract
An exact spacetime parity replicates the SU(2) × U(1) electroweak interaction, the Higgs boson
H
, and the matter of the Standard Model. This “Higgs Parity” and the mirror electroweak ...symmetry are spontaneously broken at scale
v
′ = 〈
H
′ 〉 ≫ 〈
H
〉, yielding the Standard Model below
v
′ with a quartic coupling that essentially vanishes at
v
′:
λ
SM
(
v
′) ∼ 10
−3
. The strong CP problem is solved as Higgs parity forces the masses of mirror quarks and ordinary quarks to have opposite phases. Dark matter is composed of mirror electrons,
e
′, stabilized by unbroken mirror electromagnetism. These interact with Standard Model particles via kinetic mixing between the photon and the mirror photon, which arises at four-loop level and is a firm prediction of the theory. Physics below
v
′, including the mass and interaction of
e
′ dark matter, is described by
one fewer parameter
than in the Standard Model. The allowed range of
m
e
′
is determined by uncertainties in (
α
s
, m
t
, m
h
), so that future precision measurements of these will be correlated with the direct detection rate of
e
′ dark matter, which, together with the neutron electric dipole moment, will probe the entire parameter space.
Axiogenesis with a heavy QCD axion Co, Raymond T.; Gherghetta, Tony; Harigaya, Keisuke
The journal of high energy physics,
10/2022, Letnik:
2022, Številka:
10
Journal Article
Recenzirano
Odprti dostop
A
bstract
We demonstrate that the observed cosmological excess of matter over anti-matter may originate from a heavy QCD axion that solves the strong CP problem but has a mass much larger than that ...given by the Standard Model QCD strong dynamics. We investigate a rotation of the heavy QCD axion in field space, which is transferred into a baryon asymmetry through weak and strong sphaleron processes. This provides a strong cosmological motivation for heavy QCD axions, which are of high experimental interest. The viable parameter space has an axion mass
m
a
between 1 MeV and 10 GeV and a decay constant
f
a
<
10
5
GeV, which can be probed by accelerator-based direct axion searches and observations of the cosmic microwave background.
A
bstract
Generating axion dark matter through the kinetic misalignment mechanism implies the generation of large asymmetries for Standard Model fermions in the early universe. Even if these ...asymmetries are washed out at later times, they can trigger a chiral plasma instability in the early universe. Similarly, a direct coupling of the axion with the hypercharge gauge field can trigger a tachyonic instability. These instabilities produce helical magnetic fields, which are preserved until the electroweak phase transition. At the electroweak phase transition, these become a source of baryon asymmetry, which can be much more efficient than the original axiogenesis proposal. We discuss constraints on axion dark matter production from the overproduction of the baryon asymmetry as well as a minimal, albeit fine-tuned setup, where both the correct dark matter abundance and baryon asymmetry can be achieved. For a given axion decay constant, this leads to a sharp prediction for the mass of the radial direction of the Peccei Quinn field, which is a soft mass scale in supersymmetric theories.
A
bstract
The strong CP problem is solved in Parity symmetric theories, with the electroweak gauge group containing SU(2)
L
× SU(2)
R
broken by the minimal set of Higgs fields. Neutrino masses may be ...explained by adding the same number of gauge singlet fermions as the number of generations. The neutrino masses vanish at tree-level and are only radiatively generated, leading to larger couplings of right-handed neutrinos to Standard Model particles than with the tree-level seesaw mechanism. We compute these radiative corrections and the mixing angles between left- and right-handed neutrinos. We discuss sensitivities to these right-handed neutrinos from a variety of future experiments that search for heavy neutral leptons with masses from tens of MeV to the multi-TeV scale.
PDF
