7,006 research outputs found
Vector Meson Production in Coherent Hadronic Interactions: An update on predictions for RHIC and LHC
In this letter we update our predictions for the photoproduction of vector
mesons in coherent and collisions at RHIC and LHC energies using the
color dipole approach and the Color Glass Condensate (CGC) formalism. In
particular, we present our predictions for the first run of the LHC at half
energy and for the rapidity dependence of the ratio between the and
cross sections at RHIC energies.Comment: 4 pages, 3 figure
Signals for New Spin-1 Resonances in Electroweak Gauge Boson Pair Production at the LHC
The mechanism of electroweak symmetry breaking (EWSB) will be directly
scrutinized soon at the CERN Large Hadron Collider (LHC). We analyze the LHC
potential to look for new vector bosons associated with the EWSB sector. We
present a possible model independent approach to search for these new spin--1
resonances. We show that the analyses of the processes pp --> l^+ l^- Emiss_T,
l^\pm j j Emiss_T, l^\pm l^+ l^- Emiss_T, and l^+ l^- j j (with l=e or \mu and
j=jet) have a large reach at the LHC and can lead to the discovery or exclusion
of many EWSB scenarios such as Higgsless models.Comment: 10 pages, 11 figure
Quarkonium+ production in coherent hadron - hadron interactions at LHC energies
In this paper we study the ( and )
production in coherent hadron - hadron interactions at LHC energies.
Considering the ultrarelativistic protons as a source of photons, we estimate
the cross section using the
non-relativistic QCD (NRQCD) factorization formalism and considering different
sets of values for the matrix elements. Our results for the total cross sections and rapidity distributions at
and 14 TeV demonstrate that the experimental analysis of the
production at LHC is feasible.Comment: 6 pages, 3 figures, 1 table. Improved version with a new figure.
Version to be published in European Physical Journal
Fractal analysis of weld defect patterns obtained by radiographic tests
This paper presents a fractal analysis of radiographic patterns obtained from
specimens with three types of inserted welding defects: lack of fusion, lack of
penetration, and porosity. The study focused on patterns of carbon steel beads
from radiographs of the International Institute of Welding (IIW). The
radiographs were scanned using a greyscale with 256 levels, and the fractal
features of the surfaces constructed from the radiographic images were
characterized by means of Hurst, detrended-fluctuation, and minimal-cover
analyses. A Karhunen-Loeve transformation was then used to classify the curves
obtained from the fractal analyses of the various images, and a study of the
classification errors was performed. The obtained results indicate that fractal
analyses can be an effective additional tool for pattern recognition of weld
defects in radiographic tests.Comment: 7 pages, 2 figures. To appear AIP Conference Proceedings - QNDE 200
GHIGLS: HI mapping at intermediate Galactic latitude using the Green Bank Telescope
This paper introduces the data cubes from GHIGLS, deep Green Bank Telescope
surveys of the 21-cm line emission of HI in 37 targeted fields at intermediate
Galactic latitude. The GHIGLS fields together cover over 1000 square degrees at
9.55' spatial resolution. The HI spectra have an effective velocity resolution
about 1.0 km/s and cover at least -450 < v < +250 km/s. GHIGLS highlights that
even at intermediate Galactic latitude the interstellar medium is very complex.
Spatial structure of the HI is quantified through power spectra of maps of the
column density, NHI. For our featured representative field, centered on the
North Ecliptic Pole, the scaling exponents in power-law representations of the
power spectra of NHI maps for low, intermediate, and high velocity gas
components (LVC, IVC, and HVC) are -2.86 +/- 0.04, -2.69 +/- 0.04, and -2.59
+/- 0.07, respectively. After Gaussian decomposition of the line profiles, NHI
maps were also made corresponding to the narrow-line and broad-line components
in the LVC range; for the narrow-line map the exponent is -1.9 +/- 0.1,
reflecting more small scale structure in the cold neutral medium (CNM). There
is evidence that filamentary structure in the HI CNM is oriented parallel to
the Galactic magnetic field. The power spectrum analysis also offers insight
into the various contributions to uncertainty in the data. The effect of 21-cm
line opacity on the GHIGLS NHI maps is estimated.Comment: Accepted for publication in The Astrophysical Journal, 2015 July 16.
32 pages, 21 figures (Fig. 10 new). Minor revisions from review, particularly
Section 8 and Appendix C; results unchanged. Additional surveys added and
made available; new Appendix B. Added descriptions of available FITS files
and links to four illustrative movies on enhanced GHIGLS archive
(www.cita.utoronto.ca/GHIGLS/
Multi-q Pattern Classification of Polarization Curves
Several experimental measurements are expressed in the form of
one-dimensional profiles, for which there is a scarcity of methodologies able
to classify the pertinence of a given result to a specific group. The
polarization curves that evaluate the corrosion kinetics of electrodes in
corrosive media are an application where the behavior is chiefly analyzed from
profiles. Polarization curves are indeed a classic method to determine the
global kinetics of metallic electrodes, but the strong nonlinearity from
different metals and alloys can overlap and the discrimination becomes a
challenging problem. Moreover, even finding a typical curve from replicated
tests requires subjective judgement. In this paper we used the so-called
multi-q approach based on the Tsallis statistics in a classification engine to
separate multiple polarization curve profiles of two stainless steels. We
collected 48 experimental polarization curves in aqueous chloride medium of two
stainless steel types, with different resistance against localized corrosion.
Multi-q pattern analysis was then carried out on a wide potential range, from
cathodic up to anodic regions. An excellent classification rate was obtained,
at a success rate of 90%, 80%, and 83% for low (cathodic), high (anodic), and
both potential ranges, respectively, using only 2% of the original profile
data. These results show the potential of the proposed approach towards
efficient, robust, systematic and automatic classification of highly non-linear
profile curves.Comment: 12 pages, 7 figure
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