19,597 research outputs found
Quantum polynomial functors from e-Hecke pairs
We define a new category of quantum polynomial functors extending the quantum polynomials introduced by Hong and Yacobi. We show that our category has many properties of the category of Hong and Yacobi and is the natural setting in which one can define composition of quantum polynomial functors. Throughout the paper we highlight several key differences between the theory of classical and quantum polynomial functors
Hadronization via Coalescence
We review the quark coalescence model for hadronization in relativistic heavy
ion collisions and show how it can explain the observed large baryon to meson
ratio at intermediate transverse momentum and scaling of the elliptic flows of
identified hadrons. We also show its predictions on higher-order anisotropic
flows and discuss how quark coalescence applied to open- and hidden-charm
mesons can give insight to charm quark interactions in the quark-gluon plasma
and production in heavy ion collisions.Comment: 6 pages, 4 figures, Proceedings of 20th Winter Workshop on Nuclear
Dynamics, Trelawny Beach, Jamaica, March 15--20, 200
Gamma-ray Luminosity and Photon Index Evolution of FSRQ Blazars and Contribution to the Gamma-ray Background
We present the redshift evolutions and distributions of the gamma-ray
luminosity and photon spectral index of flat spectrum radio quasar (FSRQ) type
blazars, using non-parametric methods to obtain the evolutions and
distributions directly from the data. The sample we use for analysis consists
of almost all FSRQs observed with a greater than approximately 7 sigma
detection threshold in the first year catalog of the Fermi Gamma-ray Space
Telescope's Large Area Telescope, with redshfits as determined from optical
spectroscopy by Shaw et al. We find that FSQRs undergo rapid gamma-ray
luminosity evolution, but negligible photon index evolution, with redshift.
With these evolutions accounted for we determine the density evolution and
luminosity function of FSRQs, and calculate their total contribution to the
extragalactic gamma-ray background radiation, resolved and unresolved, which is
found to be 16(+10/-4)%, in agreement with previous studies.Comment: 9 pages, 10 figures, Accepted to Ap
Cryptanalysis of group-based key agreement protocols using subgroup distance functions
We introduce a new approach for cryptanalysis of key agreement protocols
based on noncommutative groups. This approach uses functions that estimate the
distance of a group element to a given subgroup. We test it against the
Shpilrain-Ushakov protocol, which is based on Thompson's group F
Effect of resonance decays on hadron elliptic flows
The influence of resonance decays on the elliptic flows of stable hadrons is
studied in the quark coalescence model. Although difference between the
elliptic flow of pions from resonance decays, except the rho meson, and that of
directly produced pions is appreciable, those for other stable hadrons are
small. Since there are more pions from the decays of rho mesons than from other
resonances, including resonance decays can only account partially the deviation
of final pion elliptic flow from the observed scaling of hadron elliptic flows,
i.e., the hadron elliptic flow per quark is the same at same transverse
momentum per quark. The remaining deviation can be explained by including the
effect due to the quark momentum distribution inside hadrons.Comment: 13 pages and 5 figures, version pubblished in PRC, updated references
and figure
Parker-Jeans Instability of Gaseous Disks Including the Effect of Cosmic Rays
We use linear analysis to examine the effect of cosmic rays (CRs) on the
Parker-Jeans instability of magnetized self-gravitating gaseous disks. We adopt
a slab equilibrium model in which the gravity (including self-gravity) is
perpendicular to the mid-plane, the magnetic field lies along the slab. CR is
described as a fluid and only along magnetic field lines diffusion is
considered. The linearised equations are solved numerically. The system is
susceptible to Parker-Jeans instability. In general the system is less unstable
when the CR diffusion coefficient is smaller (i.e., the coupling between the
CRs and plasma is stronger). The system is also less unstable if CR pressure is
larger. This is a reminiscence of the fact that Jeans instability and Parker
instability are less unstable when the gas pressure is larger (or temperature
is higher). Moreover, for large CR diffusion coefficient (or small CR
pressure), perturbations parallel to the magnetic field are more unstable than
those perpendicular to it. The other governing factor on the growth rate of the
perturbations in different directions is the thickness of the disk or the
strength of the external pressure on the disk. In fact, this is the determining
factor in some parameter regimes.Comment: 19pages, 14figures submitted to Ap
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