Feeding of the elliptic flow by hard partons

We propose that in nuclear collisions at the LHC the elliptic flow may get a contribution from leading hard and semihard partons which deposit energy and momentum into the hydrodynamic bulk medium. The crucial effect is that these partons induce wakes which interact and merge if they come together. The contribution to the integrated elliptic flow is estimated with the help of a toy model to about 25% of the observed value and shows strong event-by-event fluctuations.Comment: 9 pages, 3 figure

ДІАГНОСТИКА ЕНДОТЕЛІАЛЬНОЇ ДИСФУНКЦІЇ У ХВОРИХ НА АУТОІМУННИЙ ТИРЕОЇДИТ ЗА НАЯВНОСТІ АТЕРОСКЛЕРОТИЧНОГО УРАЖЕННЯ СУДИН

Поширеність аутоімунного тиреоїдиту(АІТ) в Україні за останні 10 років зросла на 68 %.АІТ є найчастішою причиною гіпотиреозу (70–80 % випадків). Ендотеліальна дисфункція (ЕД),що формується в умовах запального процесу, насьогодні розцінюється як основний патогенетич-ний чинник формування атеросклеротичногоураження судин, яке є морфологічною основоюішемічної хвороби серця (ІХС). Тому пошук пока-зових маркерів ЕД як при АІТ, так і при атероскле-розі (АС), є актуальним для оптимізації діагности-ки, оцінки перебігу та ефективності лікувальнихзаходів

Measurement of shower development and its Moli\`ere radius with a four-plane LumiCal test set-up

A prototype of a luminometer, designed for a future e+e- collider detector, and consisting at present of a four-plane module, was tested in the CERN PS accelerator T9 beam. The objective of this beam test was to demonstrate a multi-plane tungsten/silicon operation, to study the development of the electromagnetic shower and to compare it with MC simulations. The Moli\`ere radius has been determined to be 24.0 +/- 0.6 (stat.) +/- 1.5 (syst.) mm using a parametrization of the shower shape. Very good agreement was found between data and a detailed Geant4 simulation.Comment: Paper published in Eur. Phys. J., includes 25 figures and 3 Table

Fast hadron freeze-out generator, part II: noncentral collisions

The fast Monte Carlo procedure of hadron generation developed in our previous work is extended to describe noncentral collisions of nuclei. We consider different possibilities to introduce appropriate asymmetry of the freeze-out hyper-surface and flow velocity profile. For comparison with other models and experimental data we demonstrate the results based on the standard parametrizations of the hadron freeze-out hyper-surface and flow velocity profile assuming either a common chemical and thermal freeze-out or the chemically frozen evolution from chemical to thermal freeze-out. The C++ generator code is written under the ROOT framework and is available for public use at http://uhkm.jinr.ru/Comment: 27 pages including 7 figures as EPS-files; prepared using LaTeX package for publication in Physical Review

Bose-Einstein correlations of same-sign charged pions in the forward region in pp collisions at √s=7 TeV

Bose-Einstein correlations of same-sign charged pions, produced in protonproton collisions at a 7 TeV centre-of-mass energy, are studied using a data sample collected by the LHCb experiment. The signature for Bose-Einstein correlations is observed in the form of an enhancement of pairs of like-sign charged pions with small four-momentum difference squared. The charged-particle multiplicity dependence of the Bose-Einstein correlation parameters describing the correlation strength and the size of the emitting source is investigated, determining both the correlation radius and the chaoticity parameter. The measured correlation radius is found to increase as a function of increasing charged-particle multiplicity, while the chaoticity parameter is seen to decreas

Journal Staff

We present the first measurements of the differential cross section d sigma/dp(T)(gamma) for the production of an isolated photon in association with at least two b-quark jets. The measurements consider photons with rapidities vertical bar y(gamma)vertical bar < 1.0 and transverse momenta 30 < p(T)(gamma) < 200 GeV. The b-quark jets are required to have p(T)(jet) > 15 GeVand vertical bar y(jet)vertical bar < 1.5. The ratio of differential production cross sections for gamma + 2 b-jets to gamma + b-jet as a function of p(T)(gamma) is also presented. The results are based on the proton-antiproton collision data at root s = 1.96 TeV collected with the D0 detector at the Fermilab Tevatron Collider. The measured cross sections and their ratios are compared to the next- to- leading order perturbative QCD calculations as well as predictions based on the k(T)- factorization approach and those from the sherpa and pythia Monte Carlo event generators