Exploration for Degradation of Λ Polarization Produced in Relativistic Nucleus Nucleus Collisions

YE YunXiu; CHEN Zhi; RUAN TuNan; SHEN Ji; LV HaiJiang; DONG WeiJiang; SA BenHao; TAI An

Chinese Physics C> 2000, Vol. 24> Issue(2) : 125-130

Exploration for Degradation of Λ Polarization Produced in Relativistic Nucleus Nucleus Collisions

Department of Modern Physics, Univsity of Science and Technology of China, Hefei 230026, China2 CCAST World Laboratory, Beijing 100080, China3 China Institute of Atomic Energy, Beijing 102413, China4 Institute of High Energy Physics, The Chinese Academy of Sciences, Beijing 100039, China

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Abstract：
The degradation of Λ transverse polarization produced in S+Pb central collisions at energy 200 GeV per nucleon has been studied in detail. The S+Pb central collision events have been generated using Monte-Carlo generator——LUCIAE at 200 GeV per nucleon. The various factors degrading Λ transverse polarization have been analysed quantitatively. The ratios of Λ′s produced from rescattering, secondary production and decays of Σ, Ξ hyperons to the total measurable Λ′s in experiment have been investigeted and the degradation effect of these Λ on the total polarization has been determined. The simulation and calculation show that above three factors decrease the Λ transverse polarization strongly, however, can not eliminate the polarization completely when the Λ′s are assumed to be produced from hadronic gas in the final state. To explan the experimental data of vanished Λ polarization, it probably needs to consider new mechanisms of Λ production, including a weak effect of QGP formation.

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[1]

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YE YunXiu, CHEN Zhi, RUAN TuNan, SHEN Ji, LV HaiJiang, DONG WeiJiang, SA BenHao and TAI An. Exploration for Degradation of Λ Polarization Produced in Relativistic Nucleus Nucleus Collisions[J]. Chinese Physics C, 2000, 24(2): 125-130.

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Received: 1998-12-17
Revised: 1900-01-01

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通讯作者: 陈斌, bchen63@163.com

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沈阳化工大学材料科学与工程学院沈阳 110142

Exploration for Degradation of Λ Polarization Produced in Relativistic Nucleus Nucleus Collisions

Corresponding author: YE YunXiu,

Department of Modern Physics, Univsity of Science and Technology of China, Hefei 230026, China2 CCAST World Laboratory, Beijing 100080, China3 China Institute of Atomic Energy, Beijing 102413, China4 Institute of High Energy Physics, The Chinese Academy of Sciences, Beijing 100039, China

Received Date: 1998-12-17

Accepted Date: 1900-01-01

Available Online: 2000-02-05

Abstract: The degradation of Λ transverse polarization produced in S+Pb central collisions at energy 200 GeV per nucleon has been studied in detail. The S+Pb central collision events have been generated using Monte-Carlo generator——LUCIAE at 200 GeV per nucleon. The various factors degrading Λ transverse polarization have been analysed quantitatively. The ratios of Λ′s produced from rescattering, secondary production and decays of Σ, Ξ hyperons to the total measurable Λ′s in experiment have been investigeted and the degradation effect of these Λ on the total polarization has been determined. The simulation and calculation show that above three factors decrease the Λ transverse polarization strongly, however, can not eliminate the polarization completely when the Λ′s are assumed to be produced from hadronic gas in the final state. To explan the experimental data of vanished Λ polarization, it probably needs to consider new mechanisms of Λ production, including a weak effect of QGP formation.

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Exploration for Degradation of Λ Polarization Produced in Relativistic Nucleus Nucleus Collisions

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