661 research outputs found
Cronin effect and energy conservation constraints in pA collisions at LHC and RHIC
We evaluate the Cronin effect in pA collisions at the CERN LHC and at RHIC in
the framework of Glauber-Eikonal model of initial state multiparton
interactions. Taking carefully into account all kinematical constraints of each
multi-parton interaction process we obtain a softening of the spectrum of
produced partons, improving in this way the agreement of the model with the
recent measurements of pi0 production in d+Au collisions at sqrt{s}=200 AGeV.Comment: Proceeding of 34th International Symposium on Multiparticle dynamics
(ISMD), Sonoma California, 26th-1st Aug 2004, to be published in Acta Phisica
Polonica
Hard Inelastic Interactions at Parton and Hadron Level
In the study of multiple scattering of partons in hadron-hadron collisions
the possibility of a hard inelastic process at the parton level is included in
its simplest possible way, including the transition.
The specific physical process to which the treatment is applied is the
inelastic collision of a nucleon with a heavy nucleusComment: 4 pages, talk given at XXXI International Symposium on Multiparticle
Dynamics, Sept 1-7, 2001, Datong China. URL http://ismd31.ccnu.edu.cn
Entanglement, Superselection Rules and Supersymmetric Quantum Mechanics
In this paper we show that the energy eigenstates of supersymmetric quantum
mechanics (SUSYQM) with non definite "fermion" number are entangled states.
They are "physical states" of the model provided that observables with odd
number of spin variables are allowed in the theory like it happens in the
Jaynes-Cummings model. Those states generalize the so called "spin spring"
states of the Jaynes-Cummings model which have played an important role in the
study of entanglement.Comment: 2 words added in the title, a section (IV) added in the text, a new
author joined the projec
Least-action principle and path-integral for classical mechanics
In this paper we show how the equations of motion of a superfield, which
makes its appearance in a path-integral approach to classical mechanics, can be
derived without the need of the least-action principleComment: to appear IN PHYS.REV.D (Brief Report
Fractional momentum correlations in multiple production of W bosons and of b-anti_b pairs in high energy pp collisions
Multiple parton collisions will represent a rather common feature in pp
collisions at the LHC, where regimes with very large momentum transfer may be
studied and events rare in lower energy accelerators might occur with a
significant rate. A reason of interest in large p_t regimes is that,
differently from low p_t, evolution will induce correlations in x in the
multiparton structure functions. We have estimated the cross section of
multiple production of W bosons with equal sign, where the correlations in x
induced by evolution are particularly relevant, and the cross section of
b-bar_b b-bar_b production, where the effects of evolution are much smaller.
Our result is that, in the case of multiple production of W bosons, the terms
with correlations may represent a correction of the order of 40% of the cross
sections, for pp collisions at 1 TeV c.m. energy, and a correction of the order
of 20% at 14 TeV. In the case of b-bar_b pairs the correction terms are of the
order of 10-15% at 1 TeV and of the order of 5% at 14 TeV.Comment: Submitted to Phys. Rev.
Insights on surface analysis techniques to study glass primary packaging
During the forming process of a vial by tubing glass, temperatures of up to 1200â—¦C are applied to adjust the glass viscosity. This process causes the release of volatile components such as alkali borates. Consequently, the percentage of sodium and boron measured on the inner surface of the vial can be higher than that measured on the corresponding glass tube. This study aimed to characterize the inner surface of two different borosilicate glass tubes of type I before and after the vial forming process at the nanoscale level. Quantitative elemental analysis of the surface along the vertical axis of glass tubes and vials was performed by X-ray photoelectron spectroscopy, whereas the topographical investigation was carried out by scanning electron microscopy (SEM). In the near-bottom region of a vial, which is usually the area most prone to corrosion, the SEM micrographs showed the appearance of bulges on the surface. The latter were then analyzed by time-of-flight secondary ion mass spectrometry to characterize their molecular composition. The purpose of this work is to identify possible new strategies for faster identification of factors that eventually influence chemical resistance of pharmaceutical glasses and to provide useful information needed to improve industrial processes
High-speed and high-resolution 2D and 3D elemental imaging of corroded ancient glass by laser ablation-ICP-MS
In this work, laser ablation-inductively coupled plasma-mass spectrometry was used to investigate for the first time glass weathering mechanisms using high-resolution 2D and 3D elemental maps of altered layers of ancient glass. Roman archaeological glass shards, displaying several corrosion indicators, were studied using multiple raster-scanning ablation with high depth and lateral resolution. The concentration gradients of different elements were captured (in their variations from the surface to the bulk of pristine glass) by multiple ablations on degraded regions of interest to observe the dissolution of the glass network due to the hydration and leaching processes that occur during its alteration. The results indicated an enrichment of silicon and a depletion of alkaline/alkaline earth element concentration in the first few microns of depth under the surface area suggesting that a de-alkalinisation phenomenon occurs on the glass surface when ancient items have been buried under soil for extended timeframes. The layer-by-layer elemental distribution revealed also how the composition of the archaeological glass changes from the bulk to the surface, shedding light on the leaching behaviour of glass constituents during the alteration process
Consolidation and coating treatments for glass in the cultural heritage field: A review
Consolidation and coating treatments are two types of interventions that form part of the active con- servation actions developed for historical and archaeological glass over the years. While thermoplastic and thermosetting resins are widely adopted by conservators worldwide, issues related to the toxicity and the material compatibility of these products remains unsolved. To address these issues, effort s have been made to develop new formulations that can functionally replace or exhibit performance advantages with respect to these canonical polymeric materials. In this review, we discuss the main classes of ma- terials applied thus far for protection and consolidation aims in the cultural heritage glass field, starting from the beginning of the 19th century and continuing until present days. We also assess the potential of hybrid organic-inorganic materials and full inorganic materials as alternative solutions to the limita- tions of organic materials in application. Finally, we provide our perspectives on future directions for the development of consolidation products that meet the specific requirements of the cultural heritage field
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