1,541 research outputs found
Relativistic diffusive motion in random electromagnetic fields
We show that the relativistic dynamics in a Gaussian random electromagnetic
field can be approximated by the relativistic diffusion of Schay and Dudley.
Lorentz invariant dynamics in the proper time leads to the diffusion in the
proper time. The dynamics in the laboratory time gives the diffusive transport
equation corresponding to the Juettner equilibrium at the inverse temperature
\beta^{-1}=mc^{2}. The diffusion constant is expressed by the field strength
correlation function (Kubo's formula).Comment: the version published in JP
Exploring the neutrino mass matrix at M_R scale
We discuss the neutrino mass matrix which predicts zero or small values of
|V_{13}| in MSSM and found the inequality, sin^2 2theta_{12} <= sin^2
2theta_sol, where sin^2 2theta_{12} is the mixing angle at M_R scale and sin^2
2theta_{sol} is the value determined by the solar neutrino oscillation. This
constraint says that the model which predicts a larger value of tan^2
theta_{sol} at M_R than the experimental value is excluded. In particular, the
bi-maximal mixing scheme at M_R scale is excluded, from the experimental value
tan^2 theta_sol<1. In this model, |V_{13}| and a Dirac phase at m_Z are induced
radiatively and turn out to be not small. The effective neutrino mass is
expected to be of order 0.05 eV.Comment: revtex4, 20 pages, 6 figure
Linearized Kompaneetz equation as a relativistic diffusion
We show that Kompaneetz equation describing photon diffusion in an
environment of an electron gas, when linearized around its equilibrium
distribution, coincides with the relativistic diffusion discussed in recent
publications. The model of the relativistic diffusion is related to soluble
models of imaginary time quantum mechanics. We suggest some non-linear
generalizations of the relativistic diffusion equation and their astrophysical
applications (in particular to the Sunyaev-Zeldovich effect).Comment: 12 page
Tri-Bimaximal Mixing from Twisted Friedberg-Lee Symmetry
We investigate the Friedberg-Lee (FL) symmetry and its promotion to include
the symmetry, and call that the twisted FL symmetry.Based on the
twisted FL symmetry, two possible schemes are presented toward the realistic
neutrino mass spectrum and the tri-bimaximal mixing.In the first scheme, we
suggest the semi-uniform translation of the FL symmetry.The second one is based
on the permutation family symmetry.The breaking terms, which are twisted
FL symmetric, are introduced.Some viable models in each scheme are also
presented.Comment: 14 pages, no figure. v2: 16 pages, modified some sentences, appendix
added, references added. v3: 14 pages, composition simplified, accepted
version in EPJ
Energy and entropy of relativistic diffusing particles
We discuss energy-momentum tensor and the second law of thermodynamics for a
system of relativistic diffusing particles. We calculate the energy and entropy
flow in this system. We obtain an exact time dependence of energy, entropy and
free energy of a beam of photons in a reservoir of a fixed temperature.Comment: 14 pages,some formulas correcte
Why is TeV-scale a geometric mean of neutrino mass and GUT-scale?
Among three typical energy scales, a neutrino mass scale ( 0.1
eV), a GUT scale ( GeV), and a TeV-scale (
TeV), there is a fascinating relation of . The TeV-scale, , is a new physics scale beyond the standard
model which is regarded as supersymmetry in this letter. We suggest a simple
supersymmetric neutrinophilic Higgs doublet model, which realizes the above
relation dynamically as well as the suitable through a tiny vacuum
expectation value of neutrinophilic Higgs without additional scales other than
and . A gauge coupling unification, which is an excellent
feature in the supersymmetric standard model, is preserved automatically in
this setup.Comment: 7 page
Quantifying peripheral sympathetic activations during sleep by means of an automatic method for pulse wave amplitude drop detection
TeV-scale seesaw from a multi-Higgs model
We suggest new simple model of generating tiny neutrino masses through a
TeV-scale seesaw mechanism without requiring tiny Yukawa couplings. This model
is a simple extension of the standard model by introducing extra one Higgs
singlet, and one Higgs doublet with a tiny vacuum expectation value.
Experimental constraints, electroweak precision data and no large flavor
changing neutral currents, are satisfied since the extra doublet only has a
Yukawa interaction with lepton doublets and right-handed neutrinos, and their
masses are heavy of order a TeV-scale. Since active light neutrinos are
Majorana particles, this model predicts a neutrinoless double beta decay.Comment: 21 pages, 8 figure
Oscillating Positive Airway Pressure Versus CPAP for the Treatment of Obstructive Sleep Apnea
Although continuous positive airway pressure (CPAP) is the most effective therapy for obstructive sleep apnea (OSA), it is not always well tolerated by the patients. Previous physiological studies showed that pressure oscillations applied to the pharynx could activate upper airway muscles, but it is not clear whether these pressure oscillations could be tolerated during sleep in OSA patients. The aim of this study was to assess the tolerance of oscillating positive airway pressure (O-PAP) (a CPAP device delivering high-frequency pressure oscillations to the upper airway) compared to CPAP. Fourteen OSA patients currently on CPAP [age 59.9 ± 10.1 years old, BMI 34.8 ± 7.2 kg/m(2), initial apnea-hypopnea index (AHI): 58.7 ± 25.2 events/h] used O-PAP or CPAP on two consecutive nights under polysomnography, in a single-blind randomized crossover design to assess sleep quality. A subtherapeutic pressure (70% of the optimal titrated pressure) was applied in both conditions and the residual AHI with each technique was also compared. There was no difference in measured or perceived sleep quality between the two treatment modalities (sleep efficiency 90.0% versus 88.1%, p = 0.54). Despite the small sample, we also found a trend toward a decrease in residual respiratory events with O-PAP compared to CPAP (median AHI 14.3 versus 20.5/h, p = 0.194). The good tolerance of O-PAP and the positive trend toward a reduction in residual AHI should stimulate further research on the effects of O-PAP in OSA patients
Suzaku Observation of Two Ultraluminous X-Ray Sources in NGC 1313
Two ultraluminous X-ray sources (ULXs) in the nearby Sb galaxy NGC 1313,
named X-1 and X-2, were observed with Suzaku on 2005 September 15. During the
observation for a net exposure of 28~ks (but over a gross time span of 90~ks),
both objects varied in intensity by about 50~%. The 0.4--10 keV X-ray
luminosity of X-1 and X-2 was measured as
and , respectively, with the former the
highest ever reported for this ULX. The spectrum of X-1 can be explained by a
sum of a strong and variable power-law component with a high energy cutoff, and
a stable multicolor blackbody with an innermost disk temperature of
keV. These results suggest that X-1 was in a ``very high'' state, where the
disk emission is strongly Comptonized. The absorber within NGC 1313 toward X-1
is suggested to have a subsolar oxygen abundance. The spectrum of X-2 is best
represented, in its fainter phase, by a multicolor blackbody model with the
innermost disk temperature of 1.2--1.3 keV, and becomes flatter as the source
becomes brighter. Hence X-2 is interpreted to be in a slim-disk state. These
results suggest that the two ULXs have black hole masses of a few tens to a few
hundreds solar masses.Comment: accepted for publication in PAS
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