103 research outputs found
Natural PQ symmetry in the 3-3-1 model with a minimal scalar sector
In the framework of a 3-3-1 model with a minimal scalar sector we make a
detailed study concerning the implementation of the PQ symmetry in order to
solve the strong CP problem. For the original version of the model, with only
two scalar triplets, we show that the entire Lagrangian is invariant under a
PQ-like symmetry but no axion is produced since an U(1) subgroup remains
unbroken. Although in this case the strong CP problem can still be solved, the
solution is largely disfavored since three quark states are left massless to
all orders in perturbation theory. The addition of a third scalar triplet
removes the massless quark states but the resulting axion is visible. In order
to become realistic the model must be extended to account for massive quarks
and invisible axion. We show that the addition of a scalar singlet together
with a Z_N discrete gauge symmetry can successfully accomplish these tasks and
protect the axion field against quantum gravitational effects. To make sure
that the protecting discrete gauge symmetry is anomaly free we use a discrete
version of the Green-Schwarz mechanism.Comment: 18 pages, 1 figure, 3 table
Search for Cosmic Axions using an Optical Interferometer
A high finesse optical cavity can be used to search for cosmic axions in the
mass range 10^{-6}< m_a <10^{-4} eV. Either a two-arm or a single-arm cavity is
suitable and in either case the signal as resonant sidebands imposed on the
carrier. Assuming for the local axion density the usual figure of 500 MeV/cm^3
[8], the KSVZ axion line [4] g/m_a = 0.4 Gev^{-2}, can be reached over the full
mass range in a one year search.Comment: 4 pages, 2 figur
Inflating with the QCD Axion
We show that the QCD axion can drive inflation via a series of tunneling
events. For axion models with a softly broken symmetry, the axion
potential has a series of local minima and may be modeled by a tilted
cosine. Chain inflation results along this tilted cosine: the field tunnels
from an initial minimum near the top of the potential through a series of ever
lower minima to the bottom. This results in sufficient inflation and reheating.
QCD axions, potentially detectable in current searches, may thus simultaneously
solve problems in particle physics and provide inflation.Comment: 5 pages, 1 figure, revised for submission to PR
QCD Sum Rule Calculation of Twist-3 Contributions to Polarized Nucleon Structure Functions
Using the framework of QCD sum rules we predict the twist-3 contribution to
the second moment of the polarized nucleon structure function . As the
relevant local operator depends explicitely on the gluon field, we employ a
recently studied interpolating nucleon current which contains three quark field
and one gluon field operator. Despite the fact that our calculation is based on
the analysis of a completely different correlation function, our estimates are
consitent with those of Balitsky, Braun and Kolesnichenko who used a
three-quark current.Comment: 16pp. , 2 figures (uuencoded eps-files), LateX. Some misprints
corrected, results unchange
Constraints on the axion-electron coupling for solar axions produced by Compton process and bremsstrahlung
The search for solar axions produced by Compton () and bremsstrahlung-like () processes has
been performed. The axion flux in the both cases depends on the axion-electron
coupling constant. The resonant excitation of low-lying nuclear level of
was looked for: Tm Tm
Tm (8.41 keV). The Si(Li) detector and
Tm target installed inside the low-background setup were used to detect
8.41 keV -rays. As a result, a new model independent restriction on the
axion-electron and the axion-nucleon couplings was obtained:
. In model of hadronic
axion this restriction corresponds to the upper limit on the axion-electron
coupling and on the axion mass eV (90%
c.l.). The limits on axion mass are 105 eV and 1.3 keV for
DFSZ- and KSVZ-axion models, correspondingly (90% c.l.).Comment: 7 pages, 4 figure
Neutrino masses and the scalar sector of a B-L extension of the standard model
We consider an electroweak model based on the gauge symmetry SU(2)_L X
U(1)_Y' X U(1)_B-L which has right-handed neutrinos with different exotic B-L
quantum numbers. Because of this particular feature we are able to write Yukawa
terms, and right-handed neutrino mass terms, with scalar fields that can
develop vacuum expectation values belonging to different energy scales. We make
a detailed study of the scalar and the Yukawa neutrino sectors to show that
this model is compatible with the observed solar and atmospheric neutrino mass
scales and the tribimaximal mixing matrix.We also show that there are dark
matter candidates if a Z_2 symmetry is included.Comment: 23 pages, 2 tables, version to be published in Phys. Rev.
Detailed design of a resonantly-enhanced axion-photon regeneration experiment
A resonantly-enhanced photon-regeneration experiment to search for the axion
or axion-like particles is described. This experiment is a shining light
through walls study, where photons travelling through a strong magnetic field
are (in part) converted to axions; the axions can pass through an opaque wall
and convert (in part) back to photons in a second region of strong magnetic
field. The photon regeneration is enhanced by employing matched Fabry-Perot
optical cavities, with one cavity within the axion generation magnet and the
second within the photon regeneration magnet. Compared to simple single-pass
photon regeneration, this technique would result in a gain of (F/pi)^2, where F
is the finesse of each cavity. This gain could feasibly be as high as 10^(10),
corresponding to an improvement in the sensitivity to the axion-photon
coupling, g_(agg), of order (F/pi)^(1/2) ~ 300. This improvement would enable,
for the first time, a purely laboratory experiment to probe axion-photon
couplings at a level competitive with, or superior to, limits from stellar
evolution or solar axion searches. This report gives a detailed discussion of
the scheme for actively controlling the two Fabry-Perot cavities and the laser
frequencies, and describes the heterodyne signal detection system, with limits
ultimately imposed by shot noise.Comment: 10 pages, 5 figure
Electromagnetic detection of axions
Photon-to-axion conversions in the static electromagnetic fields are
reconsidered in detail by using the Feynman diagram techniques. The
differential cross sections are presented for the conversions in the presence
of the electric field of the flat condenser as well as in the magnetic field of
the solenoid. Based on our results a laboratory experiment for the production
and the detection of the axions is described. This experiment will exploit the
axion decay constant as well as the axion mass.Comment: 7 pages, latex, no figures, to appear in Phys. Lett.
Phase transition in a supersymmetric axion model
In a supersymmetric axion model where the scale for both supersymmetry
breaking and Peccei-Quinn symmetry breaking is around GeV, we find
that there is a reasonable parameter space for a strongly first order phase
transition at the scale.Comment: 5 pages, 1 figur
Light Sterile Neutrinos in the Supersymmetric U(1)' Models and Axion Models
We propose the minimal supersymmetric sterile neutrino model (MSSNM) where
the sterile neutrino masses are about 1 eV, while the active neutrino masses
and the mixings among the active and sterile neutrinos are generated during
late time phase transition. All the current experimental neutrino data include
the LSND can be explained simultaneously, and the constraints on the sterile
neutrinos from the big bang nucleosynthesis and large scale structure can be
evaded. To realize the MSSNM naturally, we consider the supersymmetric
intermediate-scale U(1)' model, the low energy U(1)' model with a secluded
U(1)'-breaking sector, and the DFSZ and KSVZ axion models. In these models, the
problem can be solved elegantly, and the 1 eV sterile neutrino masses can
be generated via high-dimensional operators. For the low energy U(1)' model
with a secluded U(1)'-breaking sector, we also present a scenario in which the
masses and mixings for the active and sterile neutrinos are all generated
during late time phase transition.Comment: RevTex4, 19 pages, References adde
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