13,369 research outputs found
Quenching of light hadrons at RHIC in a collisional energy loss scenario
We evaluate the nuclear suppression factor, for light hadrons
by taking into account the collisional energy loss. We show that in the
measured domain of RHIC the elastic process is the dominant mechanism for
the partonic energy loss.Comment: 4 pages with 3 figures, Quark Matter 2008 Proceeding
Experimental determination of the state-dependent enhancement of the electron-positron momentum density in solids
The state-dependence of the enhancement of the electron-positron momentum
density is investigated for some transition and simple metals (Cr, V, Ag and
Al). Quantitative comparison with linearized muffin-tin orbital calculations of
the corresponding quantity in the first Brillouin zone is shown to yield a
measurement of the enhancement of the s, p and d states, independent of any
parameterizations in terms of the electron density local to the positron. An
empirical correction that can be applied to a first-principles state-dependent
model is proposed that reproduces the measured state-dependence very well,
yielding a general, predictive model for the enhancement of the momentum
distribution of positron annihilation measurements, including those of angular
correlation and coincidence Doppler broadening techniques
Fermi surface of an important nano-sized metastable phase: AlLi
Nanoscale particles embedded in a metallic matrix are of considerable
interest as a route towards identifying and tailoring material properties. We
present a detailed investigation of the electronic structure, and in particular
the Fermi surface, of a nanoscale phase ( AlLi) that has so far been
inaccessible with conventional techniques, despite playing a key role in
determining the favorable material properties of the alloy (Al\nobreakdash-9
at. %\nobreakdash-Li). The ordered precipitates only form within the
stabilizing Al matrix and do not exist in the bulk; here, we take advantage of
the strong positron affinity of Li to directly probe the Fermi surface of
AlLi. Through comparison with band structure calculations, we demonstrate
that the positron uniquely probes these precipitates, and present a 'tuned'
Fermi surface for this elusive phase
A Semi-automatic Search for Giant Radio Galaxy Candidates and their Radio-Optical Follow-up
We present results of a search for giant radio galaxies (GRGs) with a
projected largest linear size in excess of 1 Mpc. We designed a computational
algorithm to identify contiguous emission regions, large and elongated enough
to serve as GRG candidates, and applied it to the entire 1.4-GHz NRAO VLA Sky
survey (NVSS). In a subsequent visual inspection of 1000 such regions we
discovered 15 new GRGs, as well as many other candidate GRGs, some of them
previously reported, for which no redshift was known. Our follow-up
spectroscopy of 25 of the brighter hosts using two 2.1-m telescopes in Mexico,
and four fainter hosts with the 10.4-m Gran Telescopio Canarias (GTC), yielded
another 24 GRGs. We also obtained higher-resolution radio images with the Karl
G. Jansky Very Large Array for GRG candidates with inconclusive radio
structures in NVSS.Comment: 4 pages, 1 figure, to appear in the proceedings of The Universe of
Digital Sky Surveys, Naples, Italy, Nov 25-28, 2014; Astrophysics and Space
Science, eds. N.R. Napolitano et a
Associated hyperon-kaon production via neutrino-nucleus scattering
We present the investigation of the neutrino-induced strangeness associated
production on nuclei in the relativistic plane wave impulse approximation
(RPWIA) framework at the intermediate neutrino energies. In this study, the
elementary hadronic weak amplitudes are embedded inside the nuclear medium for
the description of the exclusive channels of neutrino-nucleus interactions.
These amplitudes are extracted using a model-dependent evaluation of the
hadronic vertex using the Born term approximation in which the application of
the Cabibbo V-A theory and SU(3) symmetry are assumed to be valid. The nuclear
effects are included via the bound state wavefunctions of the nucleon obtained
from the relativistic mean field (RMF) models. Two kinematics settings are used
to examine various distributions of the differential cross section in the rest
frame of the target nuclei. The numerical results are obtained for the
neutrino-induced charged-current (CC) \,-production on bound
neutrons in and orbitals of C. The angular
distributions are forward peaked under both kinematic settings, whereas under
the quasifree setting the cross sections tend mimic the missing momentum
distribution of the bound nucleon inside the nucleus.Comment: This article is submitted to International Journal of Modern Physics
E (nuclear physics) and accepted on 31 October 20l
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