35 research outputs found
On the Wilson loop in the dual representation within the dual Higgs model with dual Dirac strings
The vacuum expectation value of the Wilson loop in the dual representation is
calculated in the dual Higgs model with dual Dirac strings. It is shown that
the averaged value of the Wilson loop in the dual representation obeys the
area-law falloff. Quantum fluctuations of the dual-vector and the Higgs field
around Abrikosov flux lines induced by dual Dirac strings in a dual
superconducting vacuum and string shape fluctuations are taken into account.Comment: 9 pages, latex, no figure
In-medium pion weak decay constants
In nuclear matter, the pion weak decay constant is separated into the two
components corresponding to the time and space components of the
axial-vector current. Using QCD sum rules, we compute the two decay constants
from the pseudoscalar-axial vector correlation function in the matter . It is found that the sum rule for
satisfies the in-medium Gell-Mann--Oakes--Renner (GOR) relation precisely while
the sum rule does not. The sum rule contains the non-negligible
contribution from the dimension 5 condensate in addition to the
in-medium quark condensate. Using standard set of QCD parameters and ignoring
the in-medium change of the pion mass, we obtain MeV at the nuclear
saturation density. The prediction for depends on values of the dimension
5 condensate and on the Borel mass. However, the OPE constrains that , which does not agree with the prediction from the in-medium chiral
perturbation theory. Depending on the value of the dimension 5 condensate,
at the saturation density is found to be in the range MeV
at the Borel mass GeV.Comment: 19 pages including two postscript figures, substantially revise
Geotomography with solar and supernova neutrinos
We show how by studying the Earth matter effect on oscillations of solar and
supernova neutrinos inside the Earth one can in principle reconstruct the
electron number density profile of the Earth. A direct inversion of the
oscillation problem is possible due to the existence of a very simple analytic
formula for the Earth matter effect on oscillations of solar and supernova
neutrinos. From the point of view of the Earth tomography, these oscillations
have a number of advantages over the oscillations of the accelerator or
atmospheric neutrinos, which stem from the fact that solar and supernova
neutrinos are coming to the Earth as mass eigenstates rather than flavour
eigenstates. In particular, this allows reconstruction of density profiles even
over relatively short neutrino path lengths in the Earth, and also of
asymmetric profiles. We study the requirements that future experiments must
meet to achieve a given accuracy of the tomography of the Earth.Comment: 35 pages, 7 figures; minor textual changes in section
Some constraints on the Yukawa parameters in the neutrino modification of the Standard Model (nuMSM) and CP-violation
The equations connecting elements of the Yukawa matrix to elements of the
active neutrino mass matrix in the \nu MSM theory (an extension of the Standard
Model by a singlet of three right-handed neutrinos) was analyzed, and explicit
relations for the ratio of the Yukawa matrix elements through elements of the
active neutrino mass matrix were obtained. This relation can be used for
getting more accurate constraints on the model parameters. Particularly, with
the help of the obtained results we investigated CP-violating phase in the \nu
MSM theory. We demonstrate that even in the case when elements of the active
neutrino mass matrix are real the baryon asymmetry can be generated also.Comment: 14 pages, 2 figures, many clarifications and references adde
The Effective Action For Brane Localized Gauge Fields
The low energy effective action including gauge field degrees of freedom on a
non-BPS p=2 brane embedded in a N=1, D=4 target superspace is obtained through
the method of nonlinear realizations of the associated super-Poincare
symmetries. The invariant interactions of the gauge fields and the brane
excitation modes corresponding to the Nambu-Goldstone degrees of freedom
resulting from the broken space translational symmetry and the target space
supersymmetries are determined. Brane localized matter field interactions with
the gauge fields are obtained through the construction of the combined gauge
and super-Poincare covariant derivatives for the matter fields.Comment: 12 pages, no figure
Radiative Corrections to Neutrino Mixing and CP Violation in the Minimal Seesaw Model with Leptogenesis
Radiative corrections to neutrino mixing and CP violation are analyzed in the
minimal seesaw model with two heavy right-handed neutrinos. We find that
textures of the effective Majorana neutrino mass matrix are essentially stable
against renormalization effects. Taking account of the
Frampton-Glashow-Yanagida ansatz for the Dirac neutrino Yukawa coupling matrix,
we calculate the running effects of light neutrino masses, lepton flavor mixing
angles and CP-violating phases for both (normal mass hierarchy) and
(inverted mass hierarchy) cases in the standard model and in its
minimal supersymmetric extension. Very instructive predictions for the
cosmological baryon number asymmetry via thermal leptogenesis are also given
with the help of low-energy neutrino mixing quantities.Comment: 21 pages, 6 figures; more references adde
Extrinsic CPT Violation in Neutrino Oscillations in Matter
We investigate matter-induced (or extrinsic) CPT violation effects in
neutrino oscillations in matter. Especially, we present approximate analytical
formulas for the CPT-violating probability differences for three flavor
neutrino oscillations in matter with an arbitrary matter density profile. Note
that we assume that the CPT invariance theorem holds, which means that the CPT
violation effects arise entirely because of the presence of matter. As special
cases of matter density profiles, we consider constant and step-function matter
density profiles, which are relevant for neutrino oscillation physics in
accelerator and reactor long baseline experiments as well as neutrino
factories. Finally, the implications of extrinsic CPT violation on neutrino
oscillations in matter for several past, present, and future long baseline
experiments are estimated.Comment: 47 pages, 7 figures, RevTeX4. Final version to be published in Phys.
Rev.
Exact 2-point function in Hermitian matrix model
J. Harer and D. Zagier have found a strikingly simple generating function for
exact (all-genera) 1-point correlators in the Gaussian Hermitian matrix model.
In this paper we generalize their result to 2-point correlators, using Toda
integrability of the model. Remarkably, this exact 2-point correlation function
turns out to be an elementary function - arctangent. Relation to the standard
2-point resolvents is pointed out. Some attempts of generalization to 3-point
and higher functions are described.Comment: 31 pages, 1 figur
Probing the seesaw mechanism with neutrino data and leptogenesis
In the framework of the seesaw mechanism with three heavy right-handed
Majorana neutrinos and no Higgs triplets we carry out a systematic study of the
structure of the right-handed neutrino sector. Using the current low-energy
neutrino data as an input and assuming hierarchical Dirac-type neutrino masses
, we calculate the masses and the mixing of the heavy neutrinos.
We confront the inferred properties of these neutrinos with the constraints
coming from the requirement of a successful baryogenesis via leptogenesis. In
the generic case the masses of the right-handed neutrinos are highly
hierarchical: ; the lightest mass is GeV and the generated baryon-to-photon ratio is
much smaller than the observed value. We find the special cases which
correspond to the level crossing points, with maximal mixing between two
quasi-degenerate right-handed neutrinos. Two level crossing conditions are
obtained: (1-2 crossing) and (2-3
crossing), where and are respectively the 11-entry and the
12-subdeterminant of the light neutrino mass matrix in the basis where the
neutrino Yukawa couplings are diagonal. We show that sufficient lepton
asymmetry can be produced only in the 1-2 crossing where GeV, GeV and .Comment: 30 pages, 2 eps figures, JHEP3.cls, typos corrected, note (and
references) added on non-thermal leptogenesi
Seesaw mechanism, baryon asymmetry and neutrinoless double beta decay
A simplified but very instructive analysis of the seesaw mechanism is here
performed. Assuming a nearly diagonal Dirac neutrino mass matrix, we study the
forms of the Majorana mass matrix of right-handed neutrinos, which reproduce
the effective mass matrix of left-handed neutrinos. As a further step, the
important effect of a non diagonal Dirac neutrino mass matrix is explored. The
corresponding implications for the baryogenesis via leptogenesis and for the
neutrinoless double beta decay are reviewed. We propose two distinct models
where the baryon asymmetry is enhanced.Comment: 21 pages, RevTex. Revise