Measurements of at forward rapidity in collisions at GeV

=510GeVでの陽子-陽子衝突における前方の測定

Aidala, C.*; 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425名*

Aidala, C.*; Hasegawa, Shoichi; Imai, Kenichi; Nagamiya, Shoji; Sako, Hiroyuki; Sato, Susumu; Tanida, Kiyoshi; PHENIX Collaboration*; 425 of others*

We report the first measurement of the fraction of mesons coming from -meson decay () in collisions at GeV. The measurement is performed using the forward silicon vertex detector and central vertex detector at PHENIX, which provide precise tracking and distance-of-closest-approach determinations, enabling the statistical separation of due to -meson decays from prompt . The measured value of is for with transverse momenta GeV/ and rapidity . The measured fraction at PHENIX is compared to values measured by other experiments at higher center of mass energies and to fixed-order-next-to-leading-logarithm and color-evaporation-model predictions. The cross section per unit rapidity extracted from the obtained and the PHENIX inclusive cross section measured at 200 GeV scaled with color-evaporation-model calculations, at the mean hadron rapidity in 510 GeV collisions, is b. It is consistent with the fixed-order-next-to-leading-logarithm calculations.