11,503 research outputs found
The small behavior of the gluon structure function from total cross sections
Within a QCD-based eikonal model with a dynamical infrared gluon mass scale
we discuss how the small behavior of the gluon distribution function at
moderate is directly related to the rise of total hadronic cross
sections. In this model the rise of total cross sections is driven by
gluon-gluon semihard scattering processes, where the behavior of the small
gluon distribution function exhibits the power law . Assuming that the scale is proportional to the
dynamical gluon mass one, we show that the values of obtained in this
model are compatible with an earlier result based on a specific nonperturbative
Pomeron model. We discuss the implications of this picture for the behavior of
input valence-like gluon distributions at low resolution scales.Comment: 19 pages, 3 figures; revised version; to appear in Int. J. Mod. Phys.
A QCD sum rule calculation of the decay width
To understand the nature of the , recently observed in the mass
spectrum of the system by the D0 Collaboration, we have
investigated, in a previous work, a scalar tetraquark (diquak-antidiquark)
structure for it, within the two-point QCD sum rules method. The result found
for its mass agrees well with the experimental value. Encouraged by this
finding we now extend our calculations to obtain the decay width of
to using the three-point QCD sum rule. We obtain a value of
(20.4\pm8.7)\MeV, which, on comparing with the experimental value of
21.9\pm6.4 (\mbox{sta})^{+5.0}_{-2.5}(\mbox{syst}) \MeV/c^2, reinforces the
scalar four quark nature of .Comment: Minor modifications made. Some new discussions and references adde
Comments on "Wall-plug (AC) power consumption of a very high energy e+/e- storage ring collider" by Marc Ross
The paper arXiv:1308.0735 questions some of the technical assumptions made by
the TLEP Steering Group when estimating in arXiv:1305.6498 the power
requirement for the very high energy e+e- storage ring collider TLEP. We show
that our assumptions are based solidly on CERN experience with LEP and the LHC,
as well accelerators elsewhere, and confirm our earlier baseline estimate of
the TLEP power consumption.Comment: 6 page
TLEP, first step in a long-term vision for HEP
The discovery of H(126) has renewed interest in circular e+e- colliders that
can operate as Higgs factories, which benefit from three unique
characteristics: i) high luminosity and reliability, ii) the availability of
several interaction points, iii) superior beam energy accuracy. TLEP is an e+e-
storage ring of 80-km circumference that can operate with very high luminosity
from the Z peak (90 GeV) to the top quark pair threshold (350 GeV). It can
achieve transverse beam polarization at the Z peak and WW threshold, giving it
unparalleled accuracy on the beam energy. A preliminary study indicates that an
80 km tunnel could be constructed around CERN. Such a tunnel would allow a 100
TeV proton-proton collider to be established in the same ring (VHE-LHC),
offering a long term vision.Comment: This is a contribution to the the Snowmass process 2013: Frontier
Capabilitie
Spatial Variation in Erosion Rates in Mars Equatorial Regions Inferred from Ejecta Retention of 1-3 Km Diameter Craters
The modification of impact craters has long been used to infer the geomorphic forcing on Mars [1], as well as estimate the spatial and temporal variability of this erosion and gradation [e.g., 2]. Here, we studied the population of small primary craters (1-3 km) to understand differences in ejecta retention across equatorial Mars. Specifically, we evaluated whether craters in our study population had observable ejecta deposits (defined on the basis of distinct tone or texture with respect to their surroundings).This is a proxy for the resurfacing rate because only relatively fresh craters retain their ejecta deposits. More broadly, this is part of a larger project we are undertaking [3] to examine crater morphometry and other characteristics from CTX-derived digital terrain models (DTMs), augmented by qualitative observations
X, Y and Z States
Many new states in the charmonium mass region were recently discovered by
BaBar, Belle, CLEO-c, CDF, D0, BESIII, LHCb and CMS Collaborations. We use the
QCD Sum Rule approach to study the possible structure of some of these states.Comment: Contribution for the proceedings of the "XII Quark Confinement and
the Hadron Spectrum - CONF12" conferenc
Elastic scattering and the proton form factor
We compute the differential and the total cross sections for scattering
using the QCD pomeron model proposed by Landshoff and Nachtmann. This model is
quite dependent on the experimental electromagnetic form factor, and it is not
totally clear why this form factor gives good results even at moderate
transferred momentum. We exchange the eletromagnetic form factor by the
asymptotic QCD proton form factor determined by Brodsky and Lepage (BL) plus a
prescription for its low energy behavior dictated by the existence of a
dynamically generated gluon mass. We fit the data with this QCD inspired form
factor and a value for the dynamical gluon mass consistent with the ones
determined in the literature. Our results also provide a new determination of
the proton wave function at the origin, which appears in the BL form factor.Comment: 10 pages, 2 figures. Submitted to Physics Letters B. Submitted to
Phys. Lett.
Fruit sector strategic management: An exploration of agro-food chain actors' perception of market sustainability of apple innovation
The fresh fruit industry is a highly dynamic sector in the food market. Fresh fruit chain actors have to adapt to the changing market environment in order to face upcoming challenges. The objective of this study is to analyze the market sustainability of red-fleshed apples (RFA) by exploring consumers' and fresh fruit industry experts' and stakeholders' opinions in Italy and New Zealand. The study was carried out in Italy and New Zealand from December 2018 to June 2019 including 778 consumers and 29 expert and stakeholder interviews. Results show a promising market potential of RFA. Innovative attributes and nutritional value of RFA are the most important factors that push consumers' interest and willingness to buy RFA. New Zealand consumers and women show a higher appreciation of RFA. The nutritional value of the fruit can be a strategic marketing management attribute especially for health-conscious consumers. However, experts think the market for RFA will develop slowly, and will remain a niche product. Some stakeholders are skeptical about consumer RFA appreciation, and fear that RFA are too radical a novelty on the market. The RFA may be perceived as not natural. There is the need to coordinate food chain stakeholders' management practices on RFA. This allows to mitigate risks, set food standards acceptable for all chain stakeholders, and make sustainable economic investment on innovation
Evaluation of Ca-Based Sorbents for Gaseous HCl Emissions Adsorption
The problem of acid gas exhaust emissions treatment has not been fully resolved at present. Dry adsorption of acid gases with alkaline sorbents is currently being investigated, to improve solid sorbents. In this study, 5 types of hydrated lime were characterised and tested. The sorption capacities were measured by means of a system consisting of a feed line (HCl/N2), a thermostatic reactor and a water absorber. The physical characteristics of sorbent samples were also compared. Analyses conducted with scanning electronic microscopy revealed that sample C1 showed uniform particle distribution. Samples C2 and C3 showed the co-presence of fine and coarse particles. Sample C4 showed very fine particles with agglomeration phenomena. In sample C5, fibrous elements were found. Energy dispersive spectrometry (EDS) analyses showed a similar composition of the samples, with the exception of the presence of Mg in some of them. After 30 min of testing, the following differences in sorption capacities with respect to C1 (3.59 mg g−1) were found: C2, −20%; C3, −13%; C4, −17%; C5, −3%. Higher sorption capacities were associated with more uniform particle size distributions. Conversely, agglomeration of fine particles may have adversely affected the performance of sorbents
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