Polarization and cross section of midrapidity production in collisions at GeV

GeVでの陽子-陽子衝突における生成の断面積および偏極

Acharya, U.*; 長谷川 勝一   ; 今井 憲一*; 永宮 正治*; 佐甲 博之   ; 佐藤 進  ; 谷田 聖   ; PHENIX Collaboration*; 他344名*

Acharya, U.*; Hasegawa, Shoichi; Imai, Kenichi*; Nagamiya, Shoji*; Sako, Hiroyuki; Sato, Susumu; Tanida, Kiyoshi; PHENIX Collaboration*; 344 of others*

The PHENIX experiment has measured the spin alignment for inclusive decays in collisions at GeV at midrapidity. The angular distributions have been measured in three different polarization frames, and the three decay angular coefficients have been extracted in a full two-dimensional analysis. Previously, PHENIX saw large longitudinal net polarization at forward rapidity at the same collision energy. This analysis at midrapidity, complementary to the previous PHENIX results, sees no sizable polarization in the measured transverse momentum range of GeV/. The results are consistent with a previous one-dimensional analysis at midrapidity at GeV. The transverse-momentum-dependent cross section for midrapidity production has additionally been measured, and after comparison to world data we find a simple logarithmic dependence of the cross section on .