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Title: Production of K{sup +} and of K{sup -} mesons in heavy-ion collisions from 0.6A to 2.0A GeV incident energy

Abstract

This paper summarizes the yields and the emission patterns of K{sup +} and of K{sup -} mesons measured in inclusive C+C, Ni+Ni, and Au+Au collisions at incident energies from 0.6A to 2.0A GeV using the Kaon Spectrometer KaoS at GSI. For Ni+Ni collisions at 1.5A and at 1.93A GeV as well as for Au+Au at 1.5A GeV, detailed results are presented of the multiplicities, of the inverse slope parameters, and of the anisotropies in the angular emission patterns as a function of the collision centrality. When comparing transport-model calculations to the measured K{sup +} production yields, an agreement is only obtained for a soft nuclear equation of state (compression modulus K{sub N}{approx_equal}200 MeV). The production of K{sup -} mesons at energies around 1A to 2A GeV is dominated by the strangeness-exchange reaction K{sup -}N<-->{pi}Y (Y={lambda},{sigma}) which leads to a coupling between the K{sup -} and K{sup +} yields. However, both particle species show distinct differences in their emission patterns suggesting different freeze-out conditions for K{sup +} and K{sup -} mesons.

Authors:
;  [1]; ; ;  [2];  [3]; ; ;  [4]; ; ; ; ; ; ;  [2];  [5];  [3]; ; more »;  [6];  [6];  [7] « less
  1. Technische Universitaet Darmstadt, D-64289 Darmstadt (Germany)
  2. Gesellschaft fuer Schwerionenforschung, D-64220 Darmstadt (Germany)
  3. (Germany)
  4. Phillips-Universitaet, D-35037 Marburg (Germany)
  5. Uniwersytet Jagiellonski, PL-30059 Krakow (Poland)
  6. Forschungszentrum Dresden-Rossendorf, D-01314 Dresden (Germany)
  7. (Germany) (and others)
Publication Date:
OSTI Identifier:
20991032
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 75; Journal Issue: 2; Other Information: DOI: 10.1103/PhysRevC.75.024906; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ANISOTROPY; EMISSION; EQUATIONS OF STATE; FREEZING OUT; GEV RANGE 01-10; HEAVY ION REACTIONS; MEV RANGE 100-1000; POTASSIUM IONS; SPECTROMETERS; STRANGENESS-EXCHANGE REACTIONS; TRANSPORT THEORY

Citation Formats

Foerster, A., Oeschler, H., Uhlig, F., Lang, S., Schmah, A., Technische Universitaet Darmstadt, D-64289 Darmstadt, Boettcher, I., Kohlmeyer, B., Menzel, M., Brill, D., Koczon, P., Laue, F., Mang, M., Schwab, E., Senger, P., Speer, J., Debowski, M., Forschungszentrum Dresden-Rossendorf, D-01314 Dresden, Dohrmann, F., Naumann, L., Scheinast, W., Grosse, E., and Technische Universitaet Dresden, D-01062 Dresden. Production of K{sup +} and of K{sup -} mesons in heavy-ion collisions from 0.6A to 2.0A GeV incident energy. United States: N. p., 2007. Web. doi:10.1103/PHYSREVC.75.024906.
Foerster, A., Oeschler, H., Uhlig, F., Lang, S., Schmah, A., Technische Universitaet Darmstadt, D-64289 Darmstadt, Boettcher, I., Kohlmeyer, B., Menzel, M., Brill, D., Koczon, P., Laue, F., Mang, M., Schwab, E., Senger, P., Speer, J., Debowski, M., Forschungszentrum Dresden-Rossendorf, D-01314 Dresden, Dohrmann, F., Naumann, L., Scheinast, W., Grosse, E., & Technische Universitaet Dresden, D-01062 Dresden. Production of K{sup +} and of K{sup -} mesons in heavy-ion collisions from 0.6A to 2.0A GeV incident energy. United States. doi:10.1103/PHYSREVC.75.024906.
Foerster, A., Oeschler, H., Uhlig, F., Lang, S., Schmah, A., Technische Universitaet Darmstadt, D-64289 Darmstadt, Boettcher, I., Kohlmeyer, B., Menzel, M., Brill, D., Koczon, P., Laue, F., Mang, M., Schwab, E., Senger, P., Speer, J., Debowski, M., Forschungszentrum Dresden-Rossendorf, D-01314 Dresden, Dohrmann, F., Naumann, L., Scheinast, W., Grosse, E., and Technische Universitaet Dresden, D-01062 Dresden. Thu . "Production of K{sup +} and of K{sup -} mesons in heavy-ion collisions from 0.6A to 2.0A GeV incident energy". United States. doi:10.1103/PHYSREVC.75.024906.
@article{osti_20991032,
title = {Production of K{sup +} and of K{sup -} mesons in heavy-ion collisions from 0.6A to 2.0A GeV incident energy},
author = {Foerster, A. and Oeschler, H. and Uhlig, F. and Lang, S. and Schmah, A. and Technische Universitaet Darmstadt, D-64289 Darmstadt and Boettcher, I. and Kohlmeyer, B. and Menzel, M. and Brill, D. and Koczon, P. and Laue, F. and Mang, M. and Schwab, E. and Senger, P. and Speer, J. and Debowski, M. and Forschungszentrum Dresden-Rossendorf, D-01314 Dresden and Dohrmann, F. and Naumann, L. and Scheinast, W. and Grosse, E. and Technische Universitaet Dresden, D-01062 Dresden},
abstractNote = {This paper summarizes the yields and the emission patterns of K{sup +} and of K{sup -} mesons measured in inclusive C+C, Ni+Ni, and Au+Au collisions at incident energies from 0.6A to 2.0A GeV using the Kaon Spectrometer KaoS at GSI. For Ni+Ni collisions at 1.5A and at 1.93A GeV as well as for Au+Au at 1.5A GeV, detailed results are presented of the multiplicities, of the inverse slope parameters, and of the anisotropies in the angular emission patterns as a function of the collision centrality. When comparing transport-model calculations to the measured K{sup +} production yields, an agreement is only obtained for a soft nuclear equation of state (compression modulus K{sub N}{approx_equal}200 MeV). The production of K{sup -} mesons at energies around 1A to 2A GeV is dominated by the strangeness-exchange reaction K{sup -}N<-->{pi}Y (Y={lambda},{sigma}) which leads to a coupling between the K{sup -} and K{sup +} yields. However, both particle species show distinct differences in their emission patterns suggesting different freeze-out conditions for K{sup +} and K{sup -} mesons.},
doi = {10.1103/PHYSREVC.75.024906},
journal = {Physical Review. C, Nuclear Physics},
number = 2,
volume = 75,
place = {United States},
year = {Thu Feb 15 00:00:00 EST 2007},
month = {Thu Feb 15 00:00:00 EST 2007}
}
  • Azimuthal distributions of {pi}{sup +}, K{sup +}, and K{sup -} mesons have been measured in Au+Au reactions at 1.5A GeV and Ni+Ni reactions at 1.93A GeV. In semicentral collisions at midrapidity, {pi}{sup +} and K{sup +} mesons are emitted preferentially perpendicular to the reaction plane in both collision systems. In contrast for K{sup -} mesons in Ni+Ni reactions, an in-plane elliptic flow was observed for the first time at these incident energies.
  • We present the first spin alignment measurements for the K*{sup 0}(892) and (1020) vector mesons produced at midrapidity with transverse momenta up to 5 GeV/c at {radical}s{sub NN} = 200 GeV at RHIC. The diagonal spin-density matrix elements with respect to the reaction plane in Au+Au collisions are {rho}{sub 00} = 0.32 {+-} 0.04 (stat) {+-} 0.09 (syst) for the K*{sup 0} (0.8 < p{sub T} < 5.0 GeV/c) and {rho}{sub 00} = 0.34 {+-} 0.02 (stat) {+-} 0.03 (syst) for the {phi} (0.4 < p{sub T} < 5.0 GeV/c) and are constant with transverse momentum and collision centrality. Themore » data are consistent with the unpolarized expectation of 1/3 and thus no evidence is found for the transfer of the orbital angular momentum of the colliding system to the vector-meson spins. Spin alignments for K*{sup 0} and {phi} in Au+Au collisions were also measured with respect to the particle's production plane. The {phi} result, {rho}{sub 00} = 0.41 {+-} 0.02 (stat) {+-} 0.04 (syst), is consistent with that in p+p collisions, {rho}{sub 00} = 0.39 {+-} 0.03 (stat) {+-} 0.06 (syst), also measured in this work. The measurements thus constrain the possible size of polarization phenomena in the production dynamics of vector mesons.« less
  • We present the first spin alignment measurements for the K*{sup 0}(892) and {phi}(1020) vector mesons produced at midrapidity with transverse momenta up to 5 GeV/c at {radical}(s{sub NN})=200 GeV at RHIC. The diagonal spin-density matrix elements with respect to the reaction plane in Au+Au collisions are {rho}{sub 00}=0.32{+-}0.04 (stat) {+-} 0.09 (syst) for the K*{sup 0} (0.8<p{sub T}<5.0 GeV/c) and {rho}{sub 00}=0.34{+-}0.02 (stat) {+-} 0.03 (syst) for the {phi} (0.4<p{sub T}<5.0 GeV/c) and are constant with transverse momentum and collision centrality. The data are consistent with the unpolarized expectation of 1/3 and thus no evidence is found for the transfermore » of the orbital angular momentum of the colliding system to the vector-meson spins. Spin alignments for K*{sup 0} and {phi} in Au+Au collisions were also measured with respect to the particle's production plane. The {phi} result, {rho}{sub 00}=0.41{+-}0.02 (stat) {+-} 0.04 (syst), is consistent with that in p+p collisions, {rho}{sub 00}=0.39{+-}0.03 (stat) {+-} 0.06 (syst), also measured in this work. The measurements thus constrain the possible size of polarization phenomena in the production dynamics of vector mesons.« less
  • Inclusive {ital K}{sup +} production cross sections in the collision {sup 96}Ar+{sup 48}Ti at {ital E}{sub beam}=92 MeV/nucleon are calculated in the framework of a cooperative mechanism which had earlier been successful in explaining the subthreshold pion production cross sections. The calculated total cross section is 162 pb which is in agreement with the recent experimental evaluation {sigma}{sub {ital K}}{sup +}=(240{plus minus}150) pb. Our work appears to imply that like other subthreshold particles, subthreshold kaon productions also are governed mainly by phase space constraints.