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Simulation of U + U Collision. C. Nepali, G. Fai, D. Keane. Center for Nuclear Research, Department of Physics Kent State University. Y. X. b. HYDRO limits. STAR white paper. Introduction and Motivation. U + U Collision.
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Simulation of U + U Collision C. Nepali, G. Fai, D. Keane Center for Nuclear Research, Department of Physics Kent State University
Y X b HYDRO limits STAR white paper Introduction and Motivation
U + U Collision => P. F. Kolb, J. Sollfrank and U. Heinz, Phys. Rev. C 62, 054909 (2000) => E. V. Shuryak, Phys. Rev. C 61, 034905 (2000) => B. A. Li, Phys. Rev. C 61, 021903 (2000) => U. W. Heinz and A. Kuhlman, Phys. Rev. Lett. 94, 132301 (2005). => A. J. Kuhlman and U. Heinz, arXiv:nucl-th/0506088
Z' X',Y' Z θp Beam direction Y φp X Monte-Carlo Glauber Calculation Uranium has dominant quadrupole deformed shape. A = 238 Rsp = 1.19 A1/3 – 1.61 A-1/3 R = Rsp [ 0.91 + 0.27 cos2θ ] A. Bohr and B. R. Mottelson, Nuclear Structure, Vol. II. φp,φt => [ 0, 2π ] θp, θt => [ 0, π/2 ]
Nucleon distribution => fm Wounded nucleon => Inter-nucleon distance => rij≥ 0.4 fm Nucleon-nucleon cross-section at 200 GeV = 4.2 fm2 with x = 0.17 and k = 2.165 at 200 GeV
PHOBOS, Phys. Rev. C 65, 061901 (2002) Collision Geometry
Ideal tip-tip collision (b = 0 fm, θp= θt = 0) => Ideal body-body collision (b = 0 fm, θp= θt = π/2, φp = φt = 0) => Au + Au (at b = 0 fm) = 29.5 fm-2 Tip-tip => θp and θt≤ 10o or 20o , b ≤ 1 or 2 fm. Body-body => θp and θt≥ 70o or 80o , b ≤ 1 or 2 fm, (φp-10o) ≤φt ≤ (φp+10o) Agrees with U. Heinz and A. Kuhlman, Phys. Rev. Lett. 94, 132301 (2005)
Values of and percentage of the event class in U + U collisions relative to the number of events in the top 3% of . } Au + Au top 3% top 1% zdc cut
No smearing With smearing Smearing In real experiments, there is a fluctuation due to detector resolution and ZDC background.
top 3%, θp and θt≤ 10o, b ≤ 1 fm top 3%, θp and θt≤ 10o, b ≤ 1 fm
top 5%, θp and θt≤ 20o, b ≤ 2 fm top 3%, θp and θt≤ 20o, b ≤ 2 fm
} Top 3% } Au + Au top 3% top 1% zdc cut Tip-tip => } U + U top 3% top 1% zdc cuts
Possible solution => polarized uranium beam D. Fick, Ann, Rev. Nucl. Part. Sci. 31, 53, 1981 Conclusion No smearing => separation possible With smearing => difficult to separate