179 research outputs found
Corrigan-Ramond Extension of QCD at Nonzero Baryon Density
We investigate the Corrigan-Ramond extension of one massless flavor Quantum
Chromo Dynamics at nonzero quark chemical potential. Since the extension
requires the fermions to transform in the two index antisymmetric
representation of the gauge group, one finds that the number of possible
channels is richer than in the 't Hooft limit. We first discuss the diquark
channels and show that for a number of colors larger than three a new diquark
channel appears. We then study the infinite number of color limit and show that
the Fermi surface is unstable to the formation of the
Deryagin-Grigoriev-Rubakov chiral waves. We discover, differently from the 't
Hooft limit, the possibility of a colored chiral wave breaking the color
symmetry as well as translation invariance.Comment: RevTeX, 14 pages, 2 figure
High Energy Positrons and Gamma Radiation from Decaying Constituents of a two-component Dark Atom Model
We study a two component dark matter candidate inspired by the Minimal
Walking Technicolor model. Dark matter consists of a dominant SIMP-like dark
atom component made of bound states between primordial helium nuclei and a
doubly charged technilepton, and a small WIMP-like component made of another
dark atom bound state between a doubly charged technibaryon and a technilepton.
This scenario is consistent with direct search experimental findings because
the dominant SIMP component interacts too strongly to reach the depths of
current detectors with sufficient energy to recoil and the WIMP-like component
is too small to cause significant amount of events. In this context a
metastable technibaryon that decays to , and can in principle explain the observed positron excess by AMS-02 and
PAMELA, while being consistent with the photon flux observed by FERMI/LAT. We
scan the parameters of the model and we find the best possible fit to the
latest experimental data. We find that there is a small range of parameter
space that this scenario can be realised under certain conditions regarding the
cosmic ray propagation and the final state radiation. This range of parameters
fall inside the region where the current run of LHC can probe, and therefore it
will soon be possible to either verify or exclude conclusively this model of
dark matter.Comment: 11 pages, 4 figures, invited contribution to the special issue
"Composite dark matter" of International Journal of Modern Physics D. arXiv
admin note: text overlap with arXiv:1411.365
Boson Stars from Self-Interacting Dark Matter
We study the possibility that self-interacting bosonic dark matter forms
star-like objects. We study both the case of attractive and repulsive
self-interactions, and we focus particularly in the parameter phase space where
self-interactions can solve well standing problems of the collisionless dark
matter paradigm. We find the mass radius relations for these dark matter
bosonic stars, their density profile as well as the maximum mass they can
support.Comment: 12 pages, 6 figures; references adde
Gapless phases of color-superconducting matter
We discuss gapless color superconductivity for neutral quark matter in beta
equilibrium at zero as well as at nonzero temperature. Basic properties of
gapless superconductors are reviewed. The current progress and the remaining
problems in the understanding of the phase diagram of strange quark matter are
discussed.Comment: 8 pages, 2 figures. Plenary talk at Strangeness in Quark Matter 2004
(SQM2004), Cape Town, South Africa, 15-20 September 2004. Minor correction
Photons in gapless color-flavor-locked quark matter
We calculate the Debye and Meissner masses of a gauge boson in a material
consisting of two species of massless fermions that form a condensate of Cooper
pairs. We perform the calculation as a function of temperature, for the cases
of neutral Cooper pairs and charged Cooper pairs, and for a range of parameters
including gapped quaisparticles, and ungapped quasiparticles with both
quadratic and linear dispersion relations at low energy.
Our results are relevant to the behavior of photons and gluons in the gapless
color-flavor-locked phase of quark matter. We find that the photon's Meissner
mass vanishes, and the Debye mass shows a non-monotonic temperature dependence,
and at temperatures of order the pairing gap it drops to a minimum value of
order sqrt(alpha) times the quark chemical potential. We confirm previous
claims that at zero temperature an imaginary Meissner mass can arise from a
charged gapless condensate, and we find that at finite temperature this can
also occur for a gapped condensate.Comment: 22 pages, LaTeX; expanded discussion of temperature dependenc
Analysis of CrIS-ATMS Data Using an AIRS Science Team Version 6 - Like Retrieval Algorithm
CrIS/ATMS is flying on NPP and is scheduled to fly on JPSS-1. CrIS/ATMS has roughly equivalent capabilities to AIRS/AMSU. The AIRS Science Team Version 6 retrieval algorithm is currently producing very high quality level-3 Climate Data Records (CDR's) that will be critical for understanding climate processes AIRS CDRs should eventually cover the period September 2002 through at least 2020. CrIS/ATMS is the only scheduled follow on to AIRS AMSU. I have been asked by Ramesh Kakar if CrIS/ATMS can be counted on to adequately continue the AIRS/AMSU CDRs beyond 2020, or is something better needed? This research is being done to answer that question. A minimum requirement to obtain a yes answer is that CrIS/ATMS be analyzed using an AIRS Version 6 - like algorithm. NOAA is currently generating CrIS/ATMS products using 2 algorithms: IDPS and NUCAP
Retrieved Products from Simulated Hyperspectral Observations of a Hurricane
This research uses GCM derived products, with 1 km spatial resolution and sampled every 10 minutes, over a moving area following the track of a simulated severe Atlantic storm. Model products were aggregated over sounder footprints corresponding to 13 km in LEO, 2 km in LEO, and 5 km in GEO sampled every 72 minutes. We simulated radiances for instruments with AIRS-like spectral coverage, spectral resolution, and channel noise, using these aggregated products as the truth, and analyzed them using a slightly modified version of the operational AIRS Version-6 retrieval algorithm. Accuracy of retrievals obtained using simulated AIRS radiances with a 13 km footprint was similar to that obtained using real AIRS data. Spatial coverage and accuracy of retrievals are shown for all three sounding scenarios. The research demonstrates the potential significance of flying Advanced AIRS-like instruments on future LEO and GEO missions
Linear confinement without dilaton in bottom-up holography for walking technicolour
In PRD78(2008)055005 [arXiv:0805.1503 [hep-ph]] and PRD79(2009)075004
[arXiv:0809.1324 [hep-ph]], we constructed a holographic description of walking
technicolour theories using both a hard- and a soft-wall model. Here, we show
that the dilaton field becomes phenomenologically irrelevant for the spectrum
of spin-one resonances once a term is included in the Lagrangian that mixes the
Goldstone bosons and the longitudinal components of the axial vector mesons. We
show how this mixing affects our previous results and we make predictions about
how this description of technicolour can be tested.Comment: 7 pages, no figure
Cris-atms Retrievals Using an AIRS Science Team Version 6-like Retrieval Algorithm
CrIS is the infrared high spectral resolution atmospheric sounder launched on Suomi-NPP in 2011. CrISATMS comprise the IRMW Sounding Suite on Suomi-NPP. CrIS is functionally equivalent to AIRS, the high spectral resolution IR sounder launched on EOS Aqua in 2002 and ATMS is functionally equivalent to AMSU on EOS Aqua. CrIS is an interferometer and AIRS is a grating spectrometer. Spectral coverage, spectral resolution, and channel noise of CrIS is similar to AIRS. CrIS spectral sampling is roughly twice as coarse as AIRSAIRS has 2378 channels between 650 cm-1 and 2665 cm-1. CrIS has 1305 channels between 650 cm-1 and 2550 cm-1. Spatial resolution of CrIS is comparable to AIRS
Recent results from the STAR spin program at RHIC
The STAR experiment uses polarized p+p collisions at RHIC to determine the
contributions to the spin of the proton from gluon spin and from orbital
angular momentum of the quarks and gluons. Selective STAR measurements of the
longitudinal double spin asymmetry for inclusive jet and inclusive hadron
production are presented here. In addition, we report measurements of the
transverse spin asymmetry for di-jet production at mid-rapidity and the
transverse single-spin asymmetry for forward pi0 productionComment: 4 pages, 5 figures, presented at GHP06 conferenc
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