3,407 research outputs found
Electric Dipole Moments of Leptons in the Presence of Majorana Neutrinos
We calculate the two-loop diagrams that give a non-zero contribution to the
electric dipole moment d_l of a charged lepton l due to possible Majorana
masses of neutrinos. Using the example with one generation of the Standard
Model leptons and two heavy right-handed neutrinos, we demonstrate that the
non-vanishing result for d_l first appears in order O(m_l m_\nu^2 G_F^2), where
m_\nu is the mass of the light neutrino and the see-saw type relation is
imposed. This effect is beyond the reach of presently planned experiments.Comment: 13 page
Stellar explosions powered by the Blandford-Znajek mechanism
In this letter we briefly describe the first results of our numerical study
on the possibility of magnetic origin of relativistic jets of long duration
gamma ray bursters within the collapsar scenario. We track the collapse of
massive rotating stars onto a rotating central black hole using axisymmetric
general relativistic magnetohydrodynamic code that utilizes a realistic
equation of state of stellar matter, takes into account the cooling associated
with emission of neutrinos, and the energy losses due to dissociation of
nuclei. The neutrino heating is not included. We describe the solution for one
particular model where the progenitor star has magnetic field G. The
solution exhibits strong explosion driven by the Poynting-dominated jets whose
power exceeds . The jets originate mainly from the
black hole and they are powered via the Blandford-Znajek mechanism. The full
details of the simulations together with the results of parameter study will be
presented elsewhere. A number of simulation movies can be downloaded from
http://www.maths.leeds.ac.uk/~serguei/research/movies/anim.htmlComment: minor revision, accepted by MNRAS Letters, simulation movies can be
downloaded from
http://www.maths.leeds.ac.uk/~serguei/research/movies/anim.htm
Pion photoproduction off the proton in a gauge-invariant chiral unitary framework
We investigate pion photoproduction off the proton in a manifestly
gauge-invariant chiral unitary extension of chiral perturbation theory. In a
first step, we consider meson-baryon scattering taking into account all
next-to-leading order contact interactions. The resulting low-energy constants
are determined by a fit to s-wave pion-nucleon scattering and the low-energy
data for the reaction pi- p --> eta n. To assess the theoretical uncertainty,
we perform two different fit strategies. Having determined the low-energy
constants, we then analyse the data on the s-wave multipole amplitudes E0+ of
pion and eta photoproduction. These are parameter-free predictions, as the two
new low-energy constants are determined by the neutron and proton magnetic
moments.Comment: 23 pages, 17 figure
Modified intra prediction unit size selection algorithm for H.265/ HEVC compression systems
With the increased computational complexity of H.265/HEVC video compression fast decision on prediction unit size is essential for real-time coding applications. In this paper we provide an overview of existing intra prediction unit size decision algorithms and present our modification of one of the selection algorithms with improved compression performance
A direct empirical proof of the existence of dark matter
We present new weak lensing observations of 1E0657-558 (z=0.296), a unique
cluster merger, that enable a direct detection of dark matter, independent of
assumptions regarding the nature of the gravitational force law. Due to the
collision of two clusters, the dissipationless stellar component and the
fluid-like X-ray emitting plasma are spatially segregated. By using both
wide-field ground based images and HST/ACS images of the cluster cores, we
create gravitational lensing maps which show that the gravitational potential
does not trace the plasma distribution, the dominant baryonic mass component,
but rather approximately traces the distribution of galaxies. An 8-sigma
significance spatial offset of the center of the total mass from the center of
the baryonic mass peaks cannot be explained with an alteration of the
gravitational force law, and thus proves that the majority of the matter in the
system is unseen.Comment: Accepted for publication in ApJ
A modification for the calculation of water depth profiles in oil‐treated skin by in vivo confocal Raman microscopy
In this study, an extended calculation method for the determination of the water profiles in oil-treated skin is proposed, which is based on the calculation of the ratio between the Raman band intensities of water (3350-3550 cm−1) and keratin Amide I at 1650 cm−1. The proposed method is compared with the conventional method based on the ratio of the Raman band intensities of water (3350-3550 cm−1) and keratin at 2930 cm−1. The conventional method creates artifacts in the depth profiles of the water concentration in oil-treated skin, showing a lower amount of water in the upper and intermediate layers of the stratum corneum, which is due to the superposition of oil- and keratin-related Raman bands at 2930 cm−1. The proposed extended method shows no artifacts and has the potential to determine the water depth profiles after topical application of formulations on the skin
Formation of bound states of electrons in spherically symmetric oscillations of plasma
We study spherically symmetric oscillations of electrons in plasma in the
frame of classical electrodynamics. Firstly, we analyze the electromagnetic
potentials for the system of radially oscillating charged particles. Secondly,
we consider both free and forced spherically symmetric oscillations of
electrons. Finally, we discuss the interaction between radially oscillating
electrons through the exchange of ion acoustic waves. It is obtained that the
effective potential of this interaction can be attractive and can transcend the
Debye-Huckel potential. We suggest that oscillating electrons can form bound
states at the initial stages of the spherical plasma structure evolution. The
possible applications of the obtained results for the theory of natural
plasmoids are examined.Comment: 9 pages in LaTeX2e, no figures; paper was significantly modified, 2
new references added, some inessential mathematics was removed, many typos
were corrected; final variant to be published in Physica Script
Pairing of charged particles in a quantum plasmoid
We study a quantum spherically symmetric object which is based on radial
plasma oscillations. Such a plasmoid is supposed to exist in a dense plasma
containing electrons, ions, and neutral particles. The method of creation and
annihilation operators is applied to quantize the motion of charged particles
in a self-consistent potential. We also study the effective interaction between
oscillating particles owing to the exchange of a virtual acoustic wave, which
is excited in the neutral component of plasma. It is shown that this
interaction can be attractive and result in the formation of ion pairs. We
discuss possible applications of this phenomenon in astrophysical and
terrestrial plasmas.Comment: 17 pages, no figures, two columns, LaTeX2e; paper was significantly
revised; title was changed; 16 new references were included; the discussion
on ion-acoustic waves was added to Sec. 2; Secs. 3 and 4 were shortened; a
more detailed discussion was added to Sec. 7; accepted for publication to
J.Phys.
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