The Q2 dependence of dijet cross sections in γp interactions at HERA

被引：24

作者：

Breitweg, J

Chekanov, S

Derrick, M

Krakauer, D

Magill, S

Musgrave, B

Pellegrino, A

Repond, J

Stanek, R

Yoshida, R

Mattingly, MCK

Abbiendi, G

Anselmo, F

Antonioli, P

Bari, G

Basile, M

Bellagamba, L

Boscherini, D

Bruni, A

Bruni, G

Romeo, GC

Castellini, G

Cifarelli, L

Cindolo, F

Contin, A

Coppola, N

Corradi, M

De Pasquale, S

Giusti, P

Iacobucci, G

Laurenti, G

Levi, G

Margotti, A

Massam, T

Nania, R

Palmonari, F

Pesci, A

Polini, A

Sartorelli, G

Garcia, YZ

Zichichi, A

Amelung, C

Bornheim, A

Brock, I

Coböken, K

Crittenden, J

Deffner, R

Hartmann, H

Heinloth, K

Hilger, E

机构：

[1] Argonne Natl Lab, Argonne, IL 60439 USA

[2] Andrews Univ, Berrien Springs, MI 49104 USA

[3] Univ Bologna, Bologna, Italy

[4] Ist Nazl Fis Nucl, I-40126 Bologna, Italy

[5] Univ Bonn, Inst Phys, D-5300 Bonn, Germany

[6] Univ Bristol, HH Wills Phys Lab, Bristol BS8 1TL, Avon, England

[7] Univ Calabria, Dept Phys, I-87036 Cosenza, Italy

[8] Ist Nazl Fis Nucl, Cosenza, Italy

[9] Chonnam Natl Univ, Kwangju 500757, South Korea

[10] Columbia Univ, Nevis Labs, Irvington, NY USA

[11] Inst Nucl Phys, Krakow, Poland

[12] Acad Min & Met, Fac Phys & Nucl Techniques, Krakow, Poland

[13] Jagiellonian Univ, Dept Phys, Krakow, Poland

[14] Deutsch Elekt Synchrotron DESY, Hamburg, Germany

[15] DESY Zeuthen, Zeuthen, Germany

[16] Univ Florence, Florence, Italy

[17] Ist Nazl Fis Nucl, I-50125 Florence, Italy

[18] Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy

[19] Univ Freiburg, Fak Phys, D-7800 Freiburg, Germany

[20] Univ Glasgow, Dept Phys & Astron, Glasgow, Lanark, Scotland

[21] Univ Hamburg, Inst Expt Phys 1, Hamburg, Germany

[22] Univ Hamburg, Inst Expt Phys 2, D-2000 Hamburg, Germany

[23] Univ London Imperial Coll Sci Technol & Med, High Energy Nucl Phys Grp, London, England

[24] Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA

[25] Forschungszentrum Julich, Inst Kernphys, Julich, Germany

[26] KEK, Inst Particle & Nucl Studies, Tsukuba, Ibaraki, Japan

[27] Korea Univ, Seoul 136701, South Korea

[28] Kyungpook Natl Univ, Taegu 702701, South Korea

[29] Univ Autonoma Madrid, Dept Fis Teor, Madrid, Spain

[30] McGill Univ, Dept Phys, Montreal, PQ, Canada

[31] Meiji Gakuin Univ, Fac Gen Educ, Yokohama, Kanagawa, Japan

[32] Moscow Engn Phys Inst, Moscow 115409, Russia

[33] Moscow MV Lomonosov State Univ, Inst Nucl Phys, Moscow, Russia

[34] NIKHEF H, NL-1009 DB Amsterdam, Netherlands

[35] Univ Amsterdam, Amsterdam, Netherlands

[36] Ohio State Univ, Dept Phys, Columbus, OH 43210 USA

[37] Univ Oxford, Dept Phys, Oxford, England

[38] Univ Padua, Dipartimento Fis, Padua, Italy

[39] Ist Nazl Fis Nucl, Padua, Italy

[40] Penn State Univ, Dept Phys, University Pk, PA 16802 USA

[41] Polytech Univ, Sagamihara, Kanagawa, Japan

[42] Univ Roma La Sapienza, Dipartimento Fis, I-00185 Rome, Italy

[43] Ist Nazl Fis Nucl, Rome, Italy

[44] Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England

[45] Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA

[46] Univ Siegen, Fachbereich Phys, D-5900 Siegen, Germany

[47] Tel Aviv Univ, Raymond & Beverly Sackler Fac Exact Sci, Sch Phys, IL-69978 Tel Aviv, Israel

[48] Univ Tokyo, Dept Phys, Tokyo 113, Japan

[49] Tokyo Metropolitan Univ, Dept Phys, Tokyo, Japan

[50] Univ Turin, Dipartimento Fis Sperimentale, Turin, Italy

来源：

PHYSICS LETTERS B | 2000年 / 479卷 / 1-3期

关键词：

D O I：

10.1016/S0370-2693(00)00311-7

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

The dependence of the photon structure on the photon virtuality, Q(2), is studied by measuring the reaction e(+) p --> e(+) + jet + jet + X at photon-proton centre-of-mass energies 134 < W < 223 GeV. Events have been selected in the Q(2) ranges approximate to 0 GeV2, 0.1-0.55 GeV2, and 1.5-4.5 GeV2, having two jets with transverse energy E-f(jet) > 5.5 GeV in Ihe Final state. The dijet cross section has been measured as a Function of the fractional momentum of the photon participating in the hard process, x(gamma)(OBS). The ratio of the dijet cross section with x(gamma)(OBS) < 0.75 to that with x(gamma)(OBS) > 0.75 decreases as Q(2) increases. The data are compared with the predictions of NLO pQCD and leading-order Monte Carlo programs using various parton distribution functions of the photon. The measurements can be interpreted in terms of a resolved photon component that falls with Q(2) but remains present at values of Q(2) up to 4.5 GeV2. However, none of the models considered gives a good description of the data. (C) 2000 Elsevier Science B.V. All rights reserved.

引用

页码：37 / 52

页数：16

共 60 条

[41] Radiatively generated parton distributions of real and virtual photons -: art. no. 054019 [J].