Inclusive cross sections, charge ratio and double-helicity asymmetries for $π^+$ and $π^-$ production in $p$$+$$p$ collisions at $\sqrt{s}$=200 GeV
A. Adare, C. Aidala, N. N. Ajitanand, Y. Akiba, R. Akimoto, H. Al-Ta'ani, J. Alexander, K. R. Andrews, A. Angerami, K. Aoki, N. Apadula, E. Appelt, Y. Aramaki, … 展开作者
A. Adare, C. Aidala, N. N. Ajitanand, Y. Akiba, R. Akimoto, H. Al-Ta'ani, J. Alexander, K. R. Andrews, A. Angerami, K. Aoki, N. Apadula, E. Appelt, Y. Aramaki, R. Armendariz, E. C. Aschenauer, E. T. Atomssa, T. C. Awes, B. Azmoun, V. Babintsev, M. Bai, B. Bannier, K. N. Barish, B. Bassalleck, A. T. Basye, S. Bathe, V. Baublis, C. Baumann, A. Bazilevsky, R. Belmont, J. Ben-Benjamin, R. Bennett, D. S. Blau, J. S. Bok, K. Boyle, M. L. Brooks, D. Broxmeyer, H. Buesching, V. Bumazhnov, G. Bunce, S. Butsyk, S. Campbell, P. Castera, C. -H. Chen, C. Y. Chi, M. Chiu, I. J. Choi, J. B. Choi, R. K. Choudhury, P. Christiansen, T. Chujo, O. Chvala, V. Cianciolo, Z. Citron, B. A. Cole, Z. Conesa del Valle, M. Connors, M. Csanád, T. Csörgő, S. Dairaku, A. Datta, G. David, M. K. Dayananda, A. Denisov, A. Deshpande, E. J. Desmond, K. V. Dharmawardane, O. Dietzsch, A. Dion, M. Donadelli, O. Drapier, A. Drees, K. A. Drees, J. M. Durham, A. Durum, L. D'Orazio, Y. V. Efremenko, T. Engelmore, A. Enokizono, H. En'yo, S. Esumi, B. Fadem, D. E. Fields, M. Finger, M. Finger,, F. Fleuret, S. L. Fokin, J. E. Frantz, A. Franz, A. D. Frawley, Y. Fukao, T. Fusayasu, C. Gal, I. Garishvili, F. Giordano, A. Glenn, X. Gong, M. Gonin, Y. Goto, R. Granier de Cassagnac, N. Grau, S. V. Greene, M. Grosse Perdekamp, T. Gunji, L. Guo, H. -Å. Gustafsson, J. S. Haggerty, K. I. Hahn, H. Hamagaki, J. Hamblen, R. Han, J. Hanks, C. Harper, K. Hashimoto, E. Haslum, R. Hayano, X. He, T. K. Hemmick, T. Hester, J. C. Hill, R. S. Hollis, W. Holzmann, K. Homma, B. Hong, T. Horaguchi, Y. Hori, D. Hornback, S. Huang, T. Ichihara, R. Ichimiya, H. Iinuma, Y. Ikeda, K. Imai, M. Inaba, A. Iordanova, D. Isenhower, M. Ishihara, M. Issah, D. Ivanischev, Y. Iwanaga, B. V. Jacak, J. Jia, X. Jiang, D. John, B. M. Johnson, T. Jones, K. S. Joo, D. Jouan, J. Kamin, S. Kaneti, B. H. Kang, J. H. Kang, J. S. Kang, J. Kapustinsky, K. Karatsu, M. Kasai, D. Kawall, A. V. Kazantsev, T. Kempel, A. Khanzadeev, K. M. Kijima, B. I. Kim, D. J. Kim, E. -J. Kim, Y. -J. Kim, Y. K. Kim, E. Kinney, Á. Kiss, E. Kistenev, D. Kleinjan, P. Kline, L. Kochenda, B. Komkov, M. Konno, J. Koster, D. Kotov, A. Král, G. J. Kunde, K. Kurita, M. Kurosawa, Y. Kwon, G. S. Kyle, R. Lacey, Y. S. Lai, J. G. Lajoie, A. Lebedev, D. M. Lee, J. Lee, K. B. Lee, K. S. Lee, S. H. Lee, S. R. Lee, M. J. Leitch, M. A. L. Leite, X. Li, S. H. Lim, L. A. Linden Levy, H. Liu, M. X. Liu, B. Love, D. Lynch, C. F. Maguire, Y. I. Makdisi, A. Manion, V. I. Manko, E. Mannel, Y. Mao, H. Masui, M. McCumber, P. L. McGaughey, D. McGlinchey, C. McKinney, N. Means, M. Mendoza, B. Meredith, Y. Miake, T. Mibe, A. C. Mignerey, K. Miki, A. Milov, J. T. Mitchell, Y. Miyachi, A. K. Mohanty, H. J. Moon, Y. Morino, A. Morreale, D. P. Morrison, S. Motschwiller, T. V. Moukhanova, T. Murakami, J. Murata, S. Nagamiya, J. L. Nagle, M. Naglis, M. I. Nagy, I. Nakagawa, Y. Nakamiya, K. R. Nakamura, T. Nakamura, K. Nakano, J. Newby, M. Nguyen, M. Nihashi, R. Nouicer, A. S. Nyanin, C. Oakley, E. O'Brien, C. A. Ogilvie, M. Oka, K. Okada, A. Oskarsson, M. Ouchida, K. Ozawa, R. Pak, V. Pantuev, V. Papavassiliou, B. H. Park, I. H. Park, S. K. Park, S. F. Pate, L. Patel, H. Pei, J. -C. Peng, H. Pereira, D. Yu. Peressounko, R. Petti, C. Pinkenburg, R. P. Pisani, M. Proissl, M. L. Purschke, H. Qu, J. Rak, I. Ravinovich, K. F. Read, K. Reygers, V. Riabov, Y. Riabov, E. Richardson, D. Roach, G. Roche, S. D. Rolnick, M. Rosati, S. S. E. Rosendahl, J. G. Rubin, B. Sahlmueller, N. Saito, T. Sakaguchi, V. Samsonov, S. Sano, M. Sarsour, T. Sato, M. Savastio, S. Sawada, K. Sedgwick, R. Seidl, R. Seto, D. Sharma, I. Shein, T. -A. Shibata, K. Shigaki, H. H. Shim, M. Shimomura, K. Shoji, P. Shukla, A. Sickles, C. L. Silva, D. Silvermyr, C. Silvestre, K. S. Sim, B. K. Singh, C. P. Singh, V. Singh, M. Slunečka, T. Sodre, R. A. Soltz, W. E. Sondheim, S. P. Sorensen, I. V. Sourikova, P. W. Stankus, E. Stenlund, S. P. Stoll, T. Sugitate, A. Sukhanov, J. Sun, J. Sziklai, E. M. Takagui, A. Takahara, A. Taketani, R. Tanabe, Y. Tanaka, S. Taneja, K. Tanida, M. J. Tannenbaum, S. Tarafdar, A. Taranenko, E. Tennant, H. Themann, D. Thomas, M. Togawa, L. Tomášek, M. Tomášek, H. Torii, R. S. Towell, I. Tserruya, Y. Tsuchimoto, K. Utsunomiya, C. Vale, H. W. van Hecke, E. Vazquez-Zambrano, A. Veicht, J. Velkovska, R. Vértesi, M. Virius, A. Vossen, V. Vrba, E. Vznuzdaev, X. R. Wang, D. Watanabe, K. Watanabe, Y. Watanabe, Y. S. Watanabe, F. Wei, R. Wei, J. Wessels, S. N. White, D. Winter, C. L. Woody, R. M. Wright, M. Wysocki, Y. L. Yamaguchi, R. Yang, A. Yanovich, J. Ying, S. Yokkaichi, J. S. Yoo, Z. You, G. R. Young, I. Younus, I. E. Yushmanov, W. A. Zajc, A. Zelenski, S. Zhou
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381 authors, 13 pages, 8 figures, 4 tables, 2009 data. Submitted to Phys. Rev. D. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.html
We present the midrapidity charged pion invariant cross sections and the ratio of $π^-$-to-$π^+$ production ($5<p_T<13$ GeV/$c$), together with the double-helicity asymmetries ($5<p_T<12$ GeV/$c$) in polarized $p$$+$$p$ collisions at $\sqrt{s} = 200$ GeV. The cross section measurements are consistent with perturbative calculations in quantum chromodynamics within large uncertainties in the calculation due to the choice of factorization, renormalization, and fragmentation scales. However, the theoretical calculation of the ratio of $π^-$-to-$π^+$ production when considering these scale uncertainties overestimates the measured value, suggesting further investigation of the uncertainties on the charge-separated pion fragmentation functions is needed. Due to cancellations of uncertainties in the charge ratio, direct inclusion of these ratio data in future parameterizations should improve constraints on the flavor dependence of quark fragmentation functions to pions. By measuring charge-separated pion asymmetries, one can gain sensitivity to the sign of $ΔG$ through the opposite sign of the up and down quark helicity distributions in conjunction with preferential fragmentation of positive pions from up quarks and negative pions from down quarks. The double-helicity asymmetries presented are sensitive to the gluon helicity distribution over an $x$ range of $\sim$0.03--0.16.
Measurement of Collins asymmetries in inclusive production of pion pairs in e^+e^- collisions at BABAR
我们在质心能量接近10.6 GeV的情况下,对包含过程e^+e^-> qqbar --> pi pi X中的柯林斯不对称性进行了初步测量。我们使用BABAR实验收集的468 fb^(-1)的数据样本,并考虑强子事件中相对喷流中产生的带电π介子对。我们证实了非零柯林斯效应所观察到的先前的实验,我们研究的柯林斯不对称性作为一个函数的π分数能量和横动量,并作为一个函数的极角的分析轴。
Helicity-dependent parton distribution functions at next-to-next-to-leading order accuracy from inclusive and semi-inclusive deep-inelastic scattering data
Transverse-spin-dependent azimuthal asymmetries of pion and kaon pairs produced in muon-proton and muon-deuteron semi-inclusive deep inelastic scattering
Transverse momentum dependence of the quark helicity distributions and the Cahn effect in double-spin asymmetry $A_{LL}$ in Semi Inclusive DIS
在半包含深度非弹性散射的LO QCD部分子模型$\ell N \to \ell h X$中,利用未积分的夸克分布和碎裂函数,研究了双夸克自旋不对称性$A_{LL}$对$\bfP_{hT}$的依赖性.我们包括1/Q的运动学修正,诱导方位调制的不对称性,类似于在非极化SIDIS的卡恩效应。我们表明,$A_{LL}$和加权DSA $A_{LL}^{\cosϕ_h}$的研究允许提取的横向动量依赖的未积分螺旋度分布函数$g_{1L}^q(x,k_\perp)$ [或$Δq(x, k_\perp)]$。预测,基于一些模型的未知功能,给出了正在进行的COMPASS,HERMES和JLab实验。
Inclusive cross section and double helicity asymmetry for π^0 production in p+p collisions at sqrt(s)=200 GeV: Implications for the polarized gluon distribution in the proton
The gluon spin contribution to the proton spin from the double helicity asymmetry in inclusive pi^0 production in polarized p+p collisions at sqrt(s)=200 GeV