18,227 research outputs found
Discriminating hadronic and quark stars through gravitational waves of fluid pulsation modes
We investigate non-radial oscillations of hadronic, hybrid and pure
self-bound strange quark stars with maximum masses above the mass of the
recently observed massive pulsars PSR J1614-2230 and PSR J0348-0432 with . For the hadronic equation of state we employ different
parametrizations of a relativistic mean-field model and for quark matter we use
the MIT bag model including the effect of strong interactions and color
superconductivity. We find that the first pressure mode for strange quark stars
has a very different shape than for hadronic and hybrid stars. For strange
quarks stars the frequency of the p1 mode is larger than 6 kHz and diverge at
small stellar masses, but for hadronic and hybrid stars it is in the range 4-6
kHz. This allows an observational identification of strange stars even if extra
information such as the mass, the radius or the gravitational redshift of the
object is unavailable or uncertain. Also, we find as in previous works that the
frequency of the g-mode associated with the quark-hadron discontinuity in a
hybrid star is in the range 0.4-1 kHz for all masses. Thus, compact objects
emitting gravitational waves above 6 kHz should be interpreted as strange quark
stars and those emitting a signal within 0.4-1 kHz should be interpreted as
hybrid stars.Comment: 7 pages, 5 figure
Reply to Comments of Steuernagel on the Afshar's Experiment
We respond to criticism of our paper "Paradox in Wave-Paricle Duality for
Non-Perturbative Measurements". We disagree with Steuernagel's derivation of
the visibility of the Afshar experiment. To calculate the fringe visibility,
Steuernagel utilizes two different experimental situations, i.e. the wire grid
in the pattern minima and in the pattern maxima. In our assessment, this
proceduere cannot lead to the correct result for the complementarity properties
of wave-particle in one particular experimental set-up
Structure-dependent radiative corrections to phi -> K^+K^-/K_LK_S decays
Current predictions for the ratio of phi -> K^+K^-/K_LK_S decay rates exceed
the corresponding experimental value in about five standard deviations. By far,
the dominant sources of isospin breaking to this ratio are the phase-space
(52%) and the electromagnetic radiative (4.3%, computed within scalar QED)
corrections. Here we estimate the effects of the electromagnetic structure of
kaons and other model-dependent contributions into the radiative corrections.Comment: 8 pages, Latex, 2 .eps figure
Long-distance radiative corrections to the di-pion tau lepton decay
We evaluate the model-dependent piece of O(alpha) long-distance radiative
corrections to tau^- \to \pi^- \pi^0\nu_{\tau} decays by using a meson
dominance model. We find that these corrections to the di-pion invariant mass
spectrum are smaller than in previous calculations based on chiral perturbation
theory. The corresponding correction to the photon inclusive rate is tiny
(-0.15%) but it can be of relevance when new measurements reach better
precision.Comment: 4 pages, 2 figures. An estimate of the shift produced in the
evaluation of the h.v.p. contribution to the muon anomalous magnetic moment
is added. Version to appear in Phys. Rev.
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