Polarization of Lambda and (Lambda)over-bar in 920 GeV fixed-target proton-nucleus collisions
Polarization of Lambda and (Lambda)over-bar in 920 GeV fixed-target proton-nucleus collisions
复制标题
920 GeV 固定目标质子核碰撞中 Lambda 和 (Lambda)over-bar 的极化
DOI：
10.1016/j.physletb.2006.05.040
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发表时间：
2006
影响因子：
4.4
通讯作者：
U. Schwanke
中科院分区：
文献类型：
--
作者：
I. Abt;M. Adams;H. Albrecht;V. Amaral;A. Amorim;S. Aplin;V. Aushev;Y. Bagaturia;V. Balagura;M. Bargiotti;O. Barsukova;J. Bastos;C. Bauer;T. Bauer;A. Belkov;A. Belkov;A. Bertin;B. Bobchenko;M. Boecker;A. Bogatyrev;G. Bohm;M. Braeuer;M. Bruinsma;M. Bruschi;P. Buchholz;T. Buran;J. Carvalho;P. Conde;C. Cruse;M. Dam;K. M. Danielsen;M. Danilov;S. Castro;H. Deppe;X. Dong;H. Dreis;V. Egorytchev;K. Ehret;F. Eisele;D. Emeliyanov;S. Essenov;L. Fabbri;P. Faccioli;M. Feuerstack;J. Flammer;B. Fominykh;M. Funcke;L. Garrido;B. Giacobbe;J. Glaess;D. Goloubkov;Y. Goloubkov;A. Golutvin;I. Golutvin;I. Gorbounov;A. Gorišek;O. Gouchtchine;D. Goulart;S. Gradl;W. Gradl;Y. Guilitsky;J. Hansen;J. Hernández;W. Hofmann;T. Hott;W. Hulsbergen;U. Husemann;O. Igonkina;M. Ispiryan;T. Jagla;C. Jiang;H. Kapitza;S. Karabekyan;N. Karpenko;S. Keller;F. Khasanov;Y. Kiryushin;K. Knöpfle;H. Kolanoski;S. Korpar;S. Korpar;C. Krauss;P. Kreuzer;P. Križan;D. Kruecker;T. Kvaratskheliia;A. Lanyov;K. Lau;B. Lewendel;T. Lohse;R. Maenner;S. Masciocchi;I. Massa;L. Matchikhilian;G. medin;M. Medinnis;M. Mevius;A. Michetti;Y. Mikhailov;R. Mizuk;R. Mureşan;M. Negodaev;M. Noerenberg;S. Nowak;M. T. N. P. D. Vera;M. Ouchrif;F. Ould;C. Padilla;D. Peralta;R. Pernack;R. Pestotnik;M. Piccinini;M. Pleier;M. Poli;V. Popov;D. Pose;D. Pose;V. Pugatch;Y. Pylypchenko;J. Pyrlik;K. Reeves;D. Ressing;I. Riu;P. Robmann;V. Rybnikov;F. Sánchez;A. Sbrizzi;M. Schmelling;B. Schmidt;A. Schreiner;H. Schroeder;A. Schwartz;A. Schwarz;B. Schwenninger;B. Schwingenheuer;F. Sciacca;N. Semprini;S. Shuvalov;S. Shuvalov;L. Sözüer;S. Solunin;A. Somov;S. Somov;J. Spengler;R. Spighi;A. Spiridonov;A. Stanovnik;A. Stanovnik;M. Starič;C. Stegmann;M. Symalla;I. Tikhomirov;M. Titov;I. Tsakov;U. Uwer;C. Eldik;Y. Vassiliev;M. Villa;A. Vitale;I. Vukotic;H. Wahlberg;A. Walenta;M. Walter;J. Wang;D. Wegener;U. Werthenbach;H. Wolters;R. Wurth;A. Wurz;Y. Zaitsev;M. Zavertyaev;T. Zeuner;A. Zhelezov;Z. Zheng;R. Zimmermann;T. Živko;A. Zoccoli;A. Aleksandrov;J. Batista;F. Grimaldi;J. Kessler;S. Kupper;M. Nedden;S. Prystupa;H. Rick;I. Rostovtseva;L. Silva;H. S. Subramania;B. Lomonosov;M. Agari;I. Belotelov;S. Erhan;S. Erhan;A. Gellrich;M. Hohlmann;I. Kisel;E. Klinkby;R. Mankel;B. Petersen;U. Schwanke
用HERA-B光谱仪测量了s=41.6 GeV下pC和pW碰撞产生的Λ和Λ¯重子的偏振。测量结果涵盖了横向动量0.6 GeV/c<p⊥<1.2 GeV/c和费曼-x - 0.15<xF<0.01的运动学范围。两种不同目标的极化结果在统计误差范围内一致。在组合数据集中，xF≤−0.07时，与零的最大偏差为+0.054±0.029。在没有核效应的情况下，期望在xF=0处零极化。Λ的极化结果与先前测量的参数化一致，这些测量是在正xf值下进行的，其中Λ极化为负。Λ¯偏振测量结果与零一致。
A measurement of the polarization of Λ and Λ¯ baryons produced in pC and pW collisions at s=41.6 GeV has been performed with the HERA-B spectrometer. The measurements cover the kinematic range of 0.6 GeV/c<p⊥<1.2 GeV/c in transverse momentum and −0.15<xF<0.01 in Feynman-x. The polarization results from the two different targets agree within the statistical error. In the combined data set, the largest deviation from zero, +0.054±0.029, is measured for xF≲−0.07. Zero polarization is expected at xF=0 in the absence of nuclear effects. The polarization results for the Λ agree with a parametrization of previous measurements which were performed at positive xFvalues, where the Λ polarization is negative. Results of Λ¯ polarization measurements are consistent with zero.