Search NASA⌕ Search

SEARCH · Search NASA

Results for “Hadronization”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,423 records · Page 79
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Shadowing effects on J/ψ and Υ production at energies available at the CERN Large Hadron Collider

Proton-nucleus collisions have been used as a intermediate baseline for the determination of cold medium effects. They lie between proton-proton collisions in vacuum and nucleus-nucleus collisions which are expected to be dominated by hot matter effects. Modifications of the quark densities in nuclei relative to those of the proton are well established although those of the gluons in the nucleus are not well understood. We focus on the effect of these on quarkonium production in proton-lead collisions at the LHC at a center of mass energy of 5.02 TeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

Centrality dependence of high energy jets in p + Pb collisions at energies available at the CERN Large Hadron Collider

We investigate the recently measured centrality dependence of high energy jets in proton-lead collisions at the LHC. Here, we hypothesize that events with jets of very high energy (a few hundred GeV) are characterized by a suppressed number of soft particles, thus shifting these events into more peripheral bins. This naturally results in the suppression (enhancement) of the nuclear modification factor, R p A, in central (peripheral) collisions. Our calculations suggest that a moderate suppression of the order of 20%, for 10 3 GeV jets, can quantitatively reproduce the experimental data. Finally, we further extract the suppression factor as a function of jet energy and test our conjecture using available R p A data for various centralities.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

Measurement of the higher-order anisotropic flow coefficients for identified hadrons in Au + Au collisions at s N N = 200 GeV

In this paper, measurements of the anisotropic flow coefficients v 2 {Ψ 2 }, v 3 {Ψ 3 }, v 4 {Ψ 4 }, and v 4 {Ψ 2 } for identified particles (π ± , K ± , and p + ¯p) at midrapidity, obtained relative to the event planes Ψ m at forward rapidities in Au + Au collisions at s N N = 200 GeV , are presented as a function of collision centrality and particle transverse momenta p T . The v n coefficients show characteristic patterns consistent with hydrodynamical expansion of the matter produced in the collisions. For each harmonic n, a modified valence quark-number N q scaling [plotting v n {Ψ m }/(N q ) n/2 versus transverse kinetic energies (KE T )/N q ] is observed to yield a single curve for all the measured particle species for a broad range of KE T . A simultaneous blast-wave model fit to the observed v n {Ψ m }(p T ) coefficients and published particle spectra identifies radial flow anisotropies ρ n {Ψ m } and spatial eccentricities s n {Ψ m } at freeze-out. Finally, these are generally smaller than the initial-state participant-plane geometric eccentricities ε n {Ψ PP m } as also observed in the final eccentricity from quantum interferometry measurements with respect to the event plane.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2016

Rapidity and centrality dependence of particle production for identified hadrons in Cu + Cu collisions at s NN = 200 GeV

The BRAHMS collaboration has measured transverse momentum spectra of pions, kaons, protons, and antiprotons at rapidities 0 and 3 for Cu+Cu collisions at s NN = 200 GeV. As the collisions become more central the collective radial flow increases while the temperature of kinetic freeze-out decreases. The temperature is lower and the radial flow weaker at forward rapidity. Pion and kaon yields with transverse momenta between 1.5 and 2.5 GeV/c are suppressed for central collisions relative to scaled p + p collisions. This suppression, which increases as the collisions become more central, is consistent with jet quenching models and is also present with comparable magnitude at forward rapidity. At such rapidities, initial state effects may also be present and persistence of the meson suppression to high rapidity may reflect a combination of jet quenching and nuclear shadowing. In conclusion, the ratio of protons to mesons increases as the collisions become more central and is largest at forward rapidities.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2017

Vector-boson-tagged jet production in heavy ion collisions at energies available at the CERN Large Hadron Collider [Vector boson-tagged jet production in heavy ion collisions at the LHC]

Here, vector-boson-tagged jet production in collisions of heavy nuclei opens new opportunities to study parton shower formation and propagation in strongly interacting matter. It has been argued to provide a golden channel that can constrain the energy loss of jets in the quark-gluon plasma created in heavy ion reactions. We present theoretical results for isolated-photon-tagged and Z 0 -boson-tagged jet production in Pb + Pb collisions with √s NN = 5.02TeV at the LHC. Specifically, we evaluate the transverse momentum imbalance x JV distribution and nuclear modification factor I AA of tagged jets and compare our theoretical calculations to recent experimental measurements by ATLAS and CMS collaborations. Our analysis, which includes both collisional and radiative energy losses, sheds light on their relative importance versus the strength of jet-medium interactions and helps quantify the amount of out-of-cone radiation of predominantly prompt quark-initiated jets.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗