The super Pioneering High Energy Nuclear Interaction eXperiment (sPHENIX) at the Relativistic Heavy Ion Collider will perform high-precision measurements of jets and heavy flavor observables for a ...wide selection of nuclear collision systems, elucidating the microscopic nature of strongly interacting matter ranging from nucleons to the strongly coupled quark-gluon plasma. A prototype of the sPHENIX calorimeter system was tested at the Fermilab Test Beam Facility as experiment T-1044 in the spring of 2016. The electromagnetic calorimeter (EMCal) prototype is composed of scintillating fibers embedded in a mixture of tungsten powder and epoxy. The hadronic calorimeter (HCal) prototype is composed of tilted steel plates alternating with the plastic scintillator. Results of the test beam reveal the energy resolution for electrons in the EMCal is <inline-formula> <tex-math notation="LaTeX">2.8\%\oplus 15.5\%/\sqrt {E} </tex-math></inline-formula> and the energy resolution for hadrons in the combined EMCal plus HCal system is <inline-formula> <tex-math notation="LaTeX">13.5\%\oplus 64.9\%/\sqrt {E} </tex-math></inline-formula>. These results demonstrate that the performance of the proposed calorimeter system satisfies the sPHENIX specifications.
Using a relativistic hadron transport model, we investigate the utility of the elliptic flow excitation function as a probe for the stiffness of nuclear matter and for the onset of a possible ...quark-gluon-plasma (QGP) phase-transition at AGS energies 1 E_Beam 11 AGeV. The excitation function shows a strong dependence on the nuclear equation of state, and exhibits characteristic signatures which could signal the onset of a phase transition to the QGP.
We present the first excitation function of pi(-) intensity interferometry at Alternating Gradient Synchrotron (AGS) energies (2-8 A GeV). The sensitivity of the multidimensional correlation ...functions to the geometry and dynamics of the pion-emitting system provides a stringent test of transport models of heavy ion collisions. Detailed comparisons with a realistic transport model, both with and without an explicit nuclear mean field, suggest that the beam energy evolution in the reaction dynamics is different in the model than in the data. A significantly increased pi(-) emission time scale, which has been suggested as a signal of the onset of the transition to quark-gluon plasma, is not observed.
Two-pion correlation functions, measured as a function of azimuthal emission angle with respect to the reaction plane, provide novel information on the anisotropic shape and orientation of the ...pion-emitting zone formed in heavy ion collisions. We present the first experimental determination of this information, for semi-central Au
+
Au collisions at 2–6
A
GeV. The source extension perpendicular to the reaction plane is greater than the extension in the plane, and tilt of the pion source in coordinate space is found to be opposite its tilt in momentum space.
Directed flow measurements for Lambda hyperons are presented and compared to those for protons produced in the same Au+Au collisions (2A, 4A, and 6A GeV; b<5-6 fm). The measurements indicate that ...Lambda hyperons flow consistently in the same direction but with smaller magnitudes. A strong positive flow for Lambdas has been predicted in calculations which include the influence of the Lambda-nucleon potential. The experimental flow ratio Lambda/p is in qualitative agreement with expectations (approximately 2/3) from the quark counting rule at 2A GeV but is found to decrease with increasing beam energy.
PHENIX detector overview Ajitanand, N.N.; Akikawa, H.; Amirikas, R. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2003, Letnik:
499, Številka:
2
Journal Article
Recenzirano
Odprti dostop
The PHENIX detector is designed to perform a broad study of A–A, p–A, and p–p collisions to investigate nuclear matter under extreme conditions. A wide variety of probes, sensitive to all timescales, ...are used to study systematic variations with species and energy as well as to measure the spin structure of the nucleon. Designing for the needs of the heavy-ion and polarized-proton programs has produced a detector with unparalleled capabilities. PHENIX measures electron and muon pairs, photons, and hadrons with excellent energy and momentum resolution. The detector consists of a large number of subsystems that are discussed in other papers in this volume. The overall design parameters of the detector are presented.
An overview is given over recent measurement of flow and particle production in the energy range from 0.1 to 2 AGeV. Excitation functions for the directed sideward and the azimuthally symmetric ...transverse flow are presented and show the importance of flow phenomena in this incident energy regime. Rapidity density distributions are indicative of a system size dependence of the stopping process. The role of strange particles as a probe for the hot and dense phase of hadronic matter is discussed with respect to the production and propagation. The spectra of Kaons indicate an equilibration with the surrounding baryons during the expansion while their directed flow pattern is different from that of the nucleons.
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