http://dx.doi.org/10.1063/1.4909561by Vidaña, Isaac (Centro de Física Computacional, Department of Physics, University of Coimbra,
PT-3004-516 Coimbra (Portugal)) Read MoreCollapse

[en]

In this lecture I will briefly review some of the effects of hyperons on the properties
of neutron and proto-neutron stars. In particular, I will revise the problem of the
strong softening of the EoS, and the consequent reduction of the maximum mass, induced
by the presence of hyperons, a puzzle which has become more intringuing and difficult
to solve due the recent measurements of the unusually high masses of the millisecond
pulsars PSR J1903+0327 (1.667±0.021M_{⊙}), PSR J1614–2230
(1.97±0.04M_{⊙}), and PSR J0348+0432 (2.01±0.04M_{⊙}).
Finally, I will also examine the role of hyperons on the cooling properties of newly
born neutron stars and on the so-called r-mode instability$$$$

http://dx.doi.org/10.1088/1475-7516/2014/12/039by Xu, Xun-Jie; He, Hong-Jian (Institute of Modern Physics and Center for High Energy Physics, Tsinghua University,
Beijing 100084 (China)); Rodejohann, Werner (Max-Planck-Institut für Kernphysik, Postfach 103980, D-69029 Heidelberg (Germany)), E-mail: xunjie.xu@gmail.com, E-mail: hjhe@tsinghua.edu.cn, E-mail: werner.rodejohann@mpi-hd.mpg.de Read MoreCollapse

[en]

The recent IceCube observation of ultra-high-energy astrophysical neutrinos has begun
the era of neutrino astronomy. In this work, using the unitarity of leptonic mixing
matrix, we derive nontrivial unitarity constraints on the flavor composition of astrophysical
neutrinos detected by IceCube. Applying leptonic unitarity triangles, we deduce these
unitarity bounds from geometrical conditions, such as triangular inequalities. These
new bounds generally hold for three flavor neutrinos, and are independent of any experimental
input or the pattern of lepton mixing. We apply our unitarity bounds to derive general
constraints on the flavor compositions for three types of astrophysical neutrino sources
(and their general mixture), and compare them with the IceCube measurements. Furthermore,
we prove that for any sources without ν_{τ} neutrinos, a detected
ν_{μ} flux ratio < 1/4 will require the initial flavor composition
with more ν_{e} neutrinos than ν_{μ} neutrinos$$$$

by Laletin, M.N.; Belitskij, K.M. (NIYaU MIFI, Moscow (Russian Federation)); Kouvaris, C. (Univ. of Southern Denmark, Odense (Denmark)); Khlopov, M.Yu. (NIYaU MIFI, Moscow (Russian Federation); APC Lab., Paris (France)), E-mail: mnlaletin@mail.ru fromActual problems of physics and technology. III International youth scientific school-conference.
Book of abstractsRead MoreCollapse

http://dx.doi.org/10.1088/1475-7516/2014/05/036by Comelli, D. (INFN — Sezione di Ferrara, I-35131 Ferrara (Italy)); Nesti, F. (Gran Sasso Science Institute, viale Crispi 7, I-67100 L'Aquila (Italy)); Pilo, L. (Dipartimento di Scienze Fisiche e Chimiche, Università di L'Aquila, I-67010
L'Aquila (Italy)), E-mail: comelli@fe.infn.it, E-mail: fabrizio.nesti@aquila.infn.it, E-mail: luigi.pilo@aquila.infn.it Read MoreCollapse

[en]

We study the cosmological FRW flat solutions generated in general massive gravity
theories. Such a model are obtained adding to the Einstein General Relativity action
a peculiar non derivative potentials, function of the metric components, that induce
the propagation of five gravitational degrees of freedom. This large class of theories
includes both the case with a residual Lorentz invariance as well as the case with
rotational invariance only. It turns out that the Lorentz-breaking case is selected
as the only possibility. Moreover it turns out that that perturbations around strict
Minkowski or dS space are strongly coupled. The upshot is that even though dark energy
can be simply accounted by massive gravity modifications, its equation of state w_{eff}
has to deviate from -1. Indeed, there is an explicit relation between the strong coupling
scale of perturbations and the deviation of w_{eff} from -1. Taking into account
current limits on w_{eff} and submillimiter tests of the Newton's law
as a limit on the possible strong coupling scale, we find that it is still possible
to have a weakly coupled theory in a quasi dS background. Future experimental improvements
on short distance tests of the Newton's law may be used to tighten the deviation
of w_{eff} form -1 in a weakly coupled massive gravity theory$$$$

http://dx.doi.org/10.1088/1475-7516/2014/10/006by Staykov, Kalin V.; Yazadjiev, Stoytcho S. (Department of Theoretical Physics, Faculty of Physics, Sofia University, Sofia 1164
(Bulgaria)); Doneva, Daniela D.; Kokkotas, Kostas D. (Theoretical Astrophysics, Eberhard Karls University of Tübingen, Tübingen
72076 (Germany)), E-mail: kalin.v.staikov@gmail.com, E-mail: daniela.doneva@uni-tuebingen.de, E-mail:
yazad@phys.uni-sofia.bg, E-mail: kostas.kokkotas@uni-tuebingen.de Read MoreCollapse

[en]

In the present paper we investigate self-consistently slowly rotating neutron and
strange stars in R-squared gravity with Lagrangian f(R) = R + aR^{2},
where a is a parameter. For this purpose we first derive the equations describing
the structure of the slowly rotating compact stars in f(R)-gravity and then simultaneously
solve numerically the exterior and the interior problem. The structure of the slowly
rotating neutron stars is studied for two different hadronic equations of state and
a strange matter equation of state. The moment of inertia and its dependence on the
stellar mass and the R-squared gravity parameter a is also examined in details. The
numerical results show that the neutron star moment of inertia can be up to 30% larger
compared to the corresponding general relativistic models. This is much higher than
the change in the maximum mass induced by R-squared gravity and is beyond the EOS
uncertainty. In this way the future observations of the moment of inertia of compact
stars could allow us to distinguish between general relativity and f(R) gravity, and
more generally to test the strong field regime of gravity$$$$

http://dx.doi.org/10.1088/1475-7516/2014/08/031by Leinson, Lev B. (Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radiowave Propagation
of the Russian Academy of Science (IZMIRAN), 142190 Troitsk, Moscow (Russian Federation)), E-mail: leinson@yandex.ru Read MoreCollapse

[en]

Direct Chandra observations of a surface temperature of isolated neutron star in Cassiopeia
A (Cas A NS) and its cooling scenario which has been recently simultaneously suggested
by several scientific teams put stringent constraints on poorly known properties of
the superfluid neutron star core. It was found also that the thermal energy losses
from Cas A NS are approximately twice more intensive than it can be explained by the
neutrino emission. We use these unique data and well-defined cooling scenario to estimate
the strength of KSVZ axion interactions with neutrons. We speculate that enlarged
energy losses occur owing to emission of axions from superfluid core of the neutron
star. If the axion and neutrino losses are comparable we find c_{n}^{2}m_{a}^{2}∼ 5.7× 10^{-6} eV^{2},
where m_{a} is the axion mass, and c_{n} is the effective Peccei-Quinn
charge of the neutron. (Given the QCD uncertainties of the hadronic axion models,
the dimensionless constant c_{n} could range from -0.05 to 0.14.)$$$$

An ^{60}Fe anomaly was detected with accelerator mass spectrometry (AMS) -
a very sensitive method to measure extremely low isotopic ratios - in a 2 Myr old
layer of a ferromanganese crust. This signal is assumed to be of supernova origin
and might be linked to the observation of our solar system being located in a region
of thin, hot interstellar medium. This region, called the Local Bubble, was presumably
formed by multiple supernova explosions starting ∝14 Myr ago. Calculations suggest
that at least one of these supernovae occured close enough to the solar system to
leave a detectable ^{60}Fe trace on Earth. New AMS measurements are performed
in deep-sea sediments from the Pacific Ocean. An international collaboration of different
AMS facilities searches for signatures of the long-lived radionuclides ^{26}Al,
^{53}Mn, and ^{60}Fe in a time range from 1.7 to 3.1 Myr. Magnetostratigraphic
dating of the samples is confirmed by measurements of the cosmogenic radionuclide
^{10}Be. All ^{10}Be and ^{26}Al measurements are finished,
^{53}Mn and ^{60}Fe is in progress. First results are presented and
discussed.$$$$

Four gamma-ray sources have been associated with binary systems in our Galaxy: the
micro-quasar Cygnus X-3 and the gamma-ray binaries LS I +61 degrees 303, LS 5039 and
PSR B1259-63. These systems are composed of a massive companion star and a compact
object of unknown nature, except in PSR B1259-63 where there is a young pulsar. I
propose a comprehensive theoretical model for the high-energy gamma-ray emission and
variability in gamma-ray emitting binaries. In this model, the high-energy radiation
is produced by inverse Compton scattering of stellar photons on ultra-relativistic
electron-positron pairs injected by a young pulsar in gamma-ray binaries and in a
relativistic jet in micro-quasars. Considering anisotropic inverse Compton scattering,
pair production and pair cascade emission, the TeV gamma-ray emission is well explained
in LS 5039. Nevertheless, this model cannot account for the gamma-ray emission in
LS I +61 degrees 303 and PSR B1259-63. Other processes should dominate in these complex
systems. In Cygnus X-3, the gamma-ray radiation is convincingly reproduced by Doppler-boosted
Compton emission of pairs in a relativistic jet. Gamma-ray binaries and micro-quasars
provide a novel environment for the study of pulsar winds and relativistic jets at
very small spatial scales. (author)$$$$

According to the Big Bang model, ordinary matter would play a second role in the universe
compared to 2 mysterious components: dark matter and dark energy. Although the nature
of both components is unknown, observational hints for their existence pile up but
the direct detection of both has been unsuccessful so far. New ways have been explored
to do without the concepts of dark matter and dark energy. This document that is divided
into 3 parts presents the observational data that back the idea of dark matter and
dark energy, the experimental effort made worldwide to detect dark matter particles,
and the other ways to explain universe expansion$$$$

55 KB - http://www.iaea.org/inis/collection/NCLCollectionStore/_Public/41/123/41123607.pdf - Text Version by Bedran, Maria Luiza (Universidade Federal de Juiz de Fora (UJFJ), MG (Brazil)); Sociedade Brasileira de Fisica (SBF), Sao Paulo, SP (Brazil) Read MoreCollapse