The Role of Gluon Depletion in J/psi Suppression

The depletion of gluons as the parton flux traverses a nucleus in a heavy-ion collision can influence the production rate of heavy-quark states. Thus the suppression of $J/\psi$ can be due to gluon depletion in the initial state in addition to nuclear and hadronic absorption in the final state. A formalism is developed to describe the depletion effect. It is shown that, without constraints from other experimental facts beside the $J/\psi$ suppression data in $pA$ and $AB$ collisions, it is not possible to determine the relative importance of depletion vs absorption. Possible relevance to the enhanced suppression seen in the $Pb - Pb$ data is mentioned but not studied.Comment: 12 pages + 2 figures (in ps file), LaTex, Submitted to Phys. Rev.

Balance functions revisited

The idea of glue clusters, i.e. short-range correlations in the quark-gluon plasma close to freeze-out, is used to estimate the width of balance functions in momentum space. A good agreement is found with the recent measurements of STAR collaboration for central $Au-Au$ collisions

Temporal, Spatial, and Genomic Analyses of Enterobacteriaceae Clinical Antimicrobial Resistance in Companion Animals Reveals Phenotypes and Genotypes of One Health Concern

BackgroundAntimicrobial resistance (AMR) is a globally important one health threat. The impact of resistant infections on companion animals, and the potential public health implications of such infections, has not been widely explored, largely due to an absence of structured population-level data.ObjectivesWe aimed to efficiently capture and repurpose antimicrobial susceptibility test (AST) results data from several veterinary diagnostic laboratories (VDLs) across the United Kingdom to facilitate national companion animal clinical AMR surveillance. We also sought to harness and genotypically characterize isolates of potential AMR importance from these laboratories.MethodsWe summarized AST results for 29,330 canine and 8,279 feline Enterobacteriaceae isolates originating from companion animal clinical practice, performed between April 2016 and July 2018 from four VDLs, with submissions from 2,237 United Kingdom veterinary practice sites.ResultsEscherichia coli (E. coli) was the most commonly isolated Enterobacteriaceae in dogs (69.4% of AST results, 95% confidence interval, CI, 68.7–70.0) and cats (90.5%, CI 89.8–91.3). Multi-drug resistance was reported in 14.1% (CI 13.5–14.8) of canine and 12.0% (CI 11.1–12.9) of feline E. coli isolates. Referral practices were associated with increased E. coli 3rd generation ≤ cephalosporin resistance odds (dogs: odds ratio 2.0, CI 1.2–3.4). We selected 95 E. coli isolates for whole genome analyses, of which seven belonged to sequence type 131, also carrying the plasmid-associated extended spectrum β-lactamase gene blaCTX–M–15. The plasmid-mediated colistin resistance gene mcr-9 was also identified for the first time in companion animals.ConclusionsLinking clinical AMR data with genotypic characterization represents an efficient means of identifying important resistance trends in companion animals on a national scale.</sec

Hadronic Structure in the Decay τ−→π−π0ντ\tau^{-}\to \pi^{-}\pi^{0}\nu_{\tau}

We report on a study of the invariant mass spectrum of the hadronic system in the decay tau- -> pi- pi0 nu_tau. This study was performed with data obtained with the CLEO II detector operating at the CESR e+ e- collider. We present fits to phenomenological models in which resonance parameters associated with the rho(770) and rho(1450) mesons are determined. The pi- pi0 spectral function inferred from the invariant mass spectrum is compared with data on e+ e- -> pi+ pi- as a test of the Conserved Vector Current theorem. We also discuss the implications of our data with regard to estimates of the hadronic contribution to the muon anomalous magnetic moment.Comment: 39 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

Vector meson dominance and the rho meson

We discuss the properties of vector mesons, in particular the rho^0, in the context of the Hidden Local Symmetry (HLS) model. This provides a unified framework to study several aspects of the low energy QCD sector. Firstly, we show that in the HLS model the physical photon is massless, without requiring off field diagonalization. We then demonstrate the equivalence of HLS and the two existing representations of vector meson dominance, VMD1 and VMD2, at both tree level and one loop order. Finally the S matrix pole position is shown to provide a model and process independent means of specifying the rho mass and width, in contrast to the real axis prescription currently used in the Particle Data Group tables.Comment: 18 pages, REVTE

Strange particle production in 158 and 40 AA GeV/cc Pb-Pb and p-Be collisions

Results on strange particle production in Pb-Pb collisions at 158 and 40 $A$ GeV/$c$ beam momentum from the NA57 experiment at CERN SPS are presented. Particle yields and ratios are compared with those measured at RHIC. Strangeness enhancements with respect to p-Be reactions at the same beam momenta have been also measured: results about their dependence on centrality and collision energy are reported and discussed.Comment: Contribution to the proceedings of the "Hot Quarks 2004" Conference, July 18-24 2004, New Mexico, USA, submitted to Journal of Physics G 7 pages, 5 figure

Results on cascade production in lead-lead interactions from the NA57 experiment

The NA57 experiment has been designed to study the production of strange and multi-strange particles in Pb-Pb and p-Be collisions at the CERN SPS. The predecessor experiment WA97 has measured an enhanced abundance of strange particles in Pb-Pb collisions relative to p-A reactions at 160 GeV/c per nucleon beam momentum. NA57 has extended the WA97 measurements to investigate the evolution of the strangeness enhancement pattern as a function of the beam energy and over a wider centrality range. In this paper, we report results on cascade production for about the 60% most central collisions at 160 GeV/c per nucleon

Determination of the number of wounded nucleons in Pb+Pb collisions at 158 A GeV/c

The charged particle multiplicity distributions measured by two experiments, WA97 and NA57, in Pb+Pb collisions at 158 A GeV/c have been analyzed in the framework of the wounded nucleon model (WNM). We obtain a good description of the data within the centrality range of our samples. This allows us to make use of the measured multiplicities to estimate the number of wounded nucleons of the collision