37 research outputs found
To what extent is Gluon Confinement an empirical fact?
Experimental verifications of Confinement in hadron physics have established
the absence of charges with a fraction of the electron's charge by studying the
energy deposited in ionization tracks at high energies, and performing Millikan
experiments with charged droplets at rest. These experiments test only the
absence of particles with fractional charge in the asymptotic spectrum, and
thus "Quark" Confinement. However what theory suggests is that Color is
confined, that is, all asymptotic particles are color singlets. Since QCD is a
non-Abelian theory, the gluon force carriers (indirectly revealed in hadron
jets) are colored. We empirically examine what can be said about Gluon
Confinement based on the lack of detection of appropriate events, aiming at an
upper bound for high-energy free-gluon production.Comment: 14 pages, 12 figures, version accepted at Few Body Physic
Non-Perturbative QCD Treatment of High-Energy Hadron-Hadron Scattering
Total cross-sections and logarithmic slopes of the elastic scattering
cross-sections for different hadronic processes are calculated in the framework
of the model of the stochastic vacuum. The relevant parameters of this model, a
correlation length and the gluon condensate, are determined from scattering
data, and found to be in very good agreement with values coming from completely
different sources of information. A parameter-free relation is given between
total cross-sections and slope parameters, which is shown to be remarkably
valid up to the highest energies for which data exist.Comment: 60 pages, Heidelberg preprin
Measurement of and between 3.12 and 3.72 GeV at the KEDR detector
Using the KEDR detector at the VEPP-4M collider, we have measured
the values of and at seven points of the center-of-mass
energy between 3.12 and 3.72 GeV. The total achieved accuracy is about or
better than at most of energy points with a systematic uncertainty of
about . At the moment it is the most accurate measurement of in
this energy range
Stable Acidic Water Oxidation with a Cobalt Iron Lead Oxide Catalyst Operating via a Cobalt Selective Self Healing Mechanism
The instability and expense of anodes for water electrolyzers with acidic electrolytes can be overcome through the implementation of a cobalt-iron-lead oxide electrocatalyst, [Co–Fe–Pb]Ox, that is self-healing in the presence of dissolved metal precursors. However, the latter requirement is pernicious for the membrane and especially the cathode half-reaction since Pb2+ and Fe3+ precursors poison the state-of-the-art platinum H2 evolving catalyst. To address this, we demonstrate the invariably stable operation of [Co–Fe–Pb]Ox in acidic solutions through a cobalt-selective self-healing mechanism without the addition of Pb2+ and Fe3+ and investigate the kinetics of the process. Soft X-ray absorption spectroscopy reveals that low concentrations of Co2+ in the solution stabilize the catalytically active Co(Fe) sites. The highly promising performance of this system is showcased by steady water electrooxidation at 80±1 °C and 10 mA cm−2, using a flat electrode, at an overpotential of 0.56±0.01 V on a one-week timescale.</p
Antifungal Thiazolidines: Synthesis and Biological Evaluation of Mycosidine Congeners
Novel derivatives of Mycosidine (3,5-substituted thiazolidine-2,4-diones) are synthesized by Knoevenagel condensation and reactions of thiazolidines with chloroformates or halo-acetic acid esters. Furthermore, 5-Arylidene-2,4-thiazolidinediones and their 2-thioxo analogs containing halogen and hydroxy groups or di(benzyloxy) substituents in 5-benzylidene moiety are tested for antifungal activity in vitro. Some of the synthesized compounds exhibit high antifungal activity, both fungistatic and fungicidal, and lead to morphological changes in the Candida yeast cell wall. Based on the use of limited proteomic screening and toxicity analysis in mutants, we show that Mycosidine activity is associated with glucose transport. This suggests that this first-in-class antifungal drug has a novel mechanism of action that deserves further study. © 2022 by the authors. Licensee MDPI, Basel, Switzerland
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Multiplicity of Charged Secondaries in Interactions of Protons in an Emulsion at 400-GeV/c
The preliminary results on multiplicities of charged secondaries in proton-nucleus interactions at 400 Gev/c are presented. Multiplicity of produced particles is consistent in the first approximation with the KNO scaling hypothesis for hadron-nucleus interactions. The relations between different moments of multiplicity distribution in proton-nucleons interactions at high energies are discussed too
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Coherent Production of Charged Particles on Nuclei by 400-GeV/c Protons
Topological cross sections {delta}{sub coh}{sup (n)} (n = 1,3,5 and 7) of coherent diffractive dissociation of 400 Gev/c protons on nuclei of photoemulsion elements have been measured. Topological cross sections increase in the energy range from 20 to 400 Gev/c. This growth is the most noticeable for multiprong topologies. The total cross section of diffractive coherent production also increases from 8 to 25 mb/nucleus in this energy range. The increasing of the average multiplicity of charged particles in reaction of coherent proton dissociates is consistent with the logarithmic law <n>{sub coh} = (90.25 {+-} 0.05) inp. + (1.3 {+-} 0.25)