Angular and Current-Target Correlations in Deep Inelastic Scattering at HERA

Correlations between charged particles in deep inelastic ep scattering have been studied in the Breit frame with the ZEUS detector at HERA using an integrated luminosity of 6.4 pb-1. Short-range correlations are analysed in terms of the angular separation between current-region particles within a cone centred around the virtual photon axis. Long-range correlations between the current and target regions have also been measured. The data support predictions for the scaling behaviour of the angular correlations at high Q2 and for anti-correlations between the current and target regions over a large range in Q2 and in the Bjorken scaling variable x. Analytic QCD calculations and Monte Carlo models correctly describe the trends of the data at high Q2, but show quantitative discrepancies. The data show differences between the correlations in deep inelastic scattering and e+e- annihilation.Comment: 26 pages including 10 figures (submitted to Eur. J. Phys. C

Plastisol Foaming Process. Decomposition of the Foaming Agent, Polymer Behavior in the Corresponding Temperature Range and Resulting Foam Properties

The decomposition of azodicarbonamide, used as foaming agent in PVC - plasticizer (1/1) plastisols was studied by DSC. Nineteen different plasticizers, all belonging to the ester family, two being polymeric (polyadipates), were compared. The temperature of maximum decomposition rate (in anisothermal regime at 5 K min-1 scanning rate), ranges between 434 and 452 K. The heat of decomposition ranges between 8.7 and 12.5 J g -1. Some trends of variation of these parameters appear significant and are discussed in terms of solvent (matrix) and viscosity effects on the decomposition reactions. The shear modulus at 1 Hz frequency was determined at the temperature of maximum rate of foaming agent decomposition, and differs significantly from a sample to another. The foam density was determined at ambient temperature and the volume fraction of bubbles was used as criterion to judge the efficiency of the foaming process. The results reveal the existence of an optimal shear modulus of the order of 2 kPa that corresponds roughly to plasticizer molar masses of the order of 450 ± 50 g mol-1. Heavier plasticizers, especially polymeric ones are too difficult to deform. Lighter plasticizers such as diethyl phthalate (DEP) deform too easily and presumably facilitate bubble collapse

Current trends in cannulation and neuroprotection during surgery of the aortic arch in Europe†‡

OBJECTIVES To conduct a survey across European cardiac centres to evaluate the methods used for cerebral protection during aortic surgery involving the aortic arch. METHODS All European centres were contacted and surgeons were requested to fill out a short, comprehensive questionnaire on an internet-based platform. One-third of more than 400 contacted centres completed the survey correctly. RESULTS The most preferred site for arterial cannulation is the subclavian-axillary, both in acute and chronic presentation. The femoral artery is still frequently used in the acute condition, while the ascending aorta is a frequent second choice in the case of chronic presentation. Bilateral antegrade brain perfusion is chosen by the majority of centres (2/3 of cases), while retrograde perfusion or circulatory arrest is very seldom used and almost exclusively in acute clinical presentation. The same pumping system of the cardio pulmonary bypass is most of the time used for selective cerebral perfusion, and the perfusate temperature is usually maintained between 22 and 26°C. One-third of the centres use lower temperatures. Perfusate flow and pressure are fairly consistent among centres in the range of 10-15 ml/kg and 60 mmHg, respectively. In 60% of cases, barbiturates are added for cerebral protection, while visceral perfusion still receives little attention. Regarding cerebral monitoring, there is a general tendency to use near-infrared spectroscopy associated with bilateral radial pressure measurement. CONCLUSIONS These data represent a snapshot of the strategies used for cerebral protection during major aortic surgery in current practice, and may serve as a reference for standardization and refinement of different approache

Angular and Current-target Correlations in Deep Inelastic Scattering at HERA

Correlations between charged particles in deep inelastic e+ p scattering have been studied in the Breit frame with the ZEUS detector at HERA using an integrated luminosity of 6.4pb-1. Short-range correlations are analysed in terms of the angular separation between current-region particles within a cone centred around the virtual photon axis. Long-range correlations between the current and target regions have also been measured. The data support predictions for the scaling behaviour of the angular correlations at high Q2 and for anti-correlations between the current and target regions over a large range in Q2 and in the Bjorken scaling variable x. Analytic QCD calculations and Monte Carlo models correctly describe the trends of the data at high Q2, but show quantitative discrepancies. The data show differences between the correlations in deep inelastic scattering and e+e- annihilation

Mean-field transport theory for the two-flavour NJL model

By making decomposition of the Wigner function simultaneously in both the spinor and the isospin spaces we derive a set of kinetic equations for the quark distribution functions and the spin densities. A detailed analysis of the consequences imposed by the chiral invariance on the form of the transport equations is presented.Comment: Revtex, 25 pages, no figure

PERFORMANCE OF THE FORWARD ELECTROMAGNETIC CALORIMETER (FEMC) FOR THE END CAPS OF THE DELPHI DETECTOR

none31We present the performance of the DELPHI lead glass calorimeter with vacuum phototriode readout. The behaviour of the counters in magnetic fields up to 1.1 T is discussed. Experimental results, obtained with an electron beam from 7 to 50 GeV/c, on noise, linearity, energy and position resolution are presented.noneChecchia P.; Galeazzi G.; Gasparini U.; Lippi I.; Mazzucato M.; Pegoraro M.; Pinori C.; Simonetto F.; Ventura L.; Zumerle G.; Lopez A.; Marco J.; Ruiz A.; Bianchi F.; Cirio R.; Gamba D.; Menichetti E.; Rinaudo G.; Romero A.; Castelli E.; Lanceri L.; Poropat P.; Ragazzon R.; Sessa M.; de Angelis A.; Scuri F.; Waldner F.; Ferrer A.; Gomez J. J.; Sebastia A.; Velasco J.Checchia, P.; Galeazzi, G.; Gasparini, Ugo; Lippi, I.; Mazzucato, M.; Pegoraro, M.; Pinori, C.; Simonetto, Franco; Ventura, L.; Zumerle, Gianni; Lopez, A.; Marco, J.; Ruiz, A.; Bianchi, F.; Cirio, R.; Gamba, D.; Menichetti, E.; Rinaudo, G.; Romero, A.; Castelli, E.; Lanceri, L.; Poropat, P.; Ragazzon, R.; Sessa, M.; de Angelis, A.; Scuri, F.; Waldner, F.; Ferrer, A.; Gomez, J. J.; Sebastia, A.; Velasco, J