Measurement of the low-x behaviour of the photon structure function F-2(gamma)

Abbiendi, G Ackerstaff, K Ainsley, C Akesson, PF Alexander, G Allison, J Anderson, KJ Arcelli, S Asai, S Ashby, SF Axen, D Azuelos, G Bailey, I Ball, AH Barberio, E Barlow, RJ Baumann, S Bechtluft, J Behnke, T Bell, KW Bella, G Bellerive, A Bentvelsen, S Bethke, S Biebel, O Bloodworth, IJ Bock, P Bohme, J Boeriu, O Bonacorsi, D Boutemeur, M Braibant, S Bright-Thomas, P Brigliadori, L Brown, RM Burckhart, HJ Cammin, J Capiluppi, P Carnegie, RK Carter, AA Carter, JR Chang, CY Charlton, DG Ciocca, C Clarke, PEL Clay, E Cohen, I Cooke, OC Couchman, J Couyoumtzelis, C Coxe, RL Cuffiani, M Dado, S Dallavalle, GM Dallison, S de Roeck, A Dervan, P Desch, K Dienes, B Dixit, MS Donkers, M Dubbert, J Duchovni, E Duckeck, G Duerdoth, IP Estabrooks, PG Etzion, E Fabbri, F Fanti, M Feld, L Ferrari, P Fiedler, F Fleck, L Ford, M Frey, A Furtjes, A Futyan, DI Gagnon, P Gary, JW Gaycken, G Geich-Gimbel, C Giacomelli, G Giacomelli, P Glenzinski, D Goldberg, J Grandi, C Graham, K Gross, E Grunhaus, J Gruwe, M Gunther, PO Hajdu, C Hanson, GG Hansroul, M Hapke, M Harder, K Harel, A Hargrove, CK Harin-Dirac, M Hauke, A Hauschild, M Hawkes, CM Hawkings, R Hemingway, RJ Hensel, C Herten, G Heuer, RD Hildreth, MD Hill, JC Hocker, A Hoffman, K Homer, RJ Honma, AK Horvath, D Hossain, KR Howard, R Huntemeyer, P Igo-Kemenes, P Ishii, K Jacob, FR Jawahery, A Jeremie, H Jones, CR Jovanovic, P Junk, TR Kanaya, N Kanzaki, J Karapetian, G Karlen, D Kartvelishvili, V Kawagoe, K Kawamoto, T Keeler, RK Kellogg, RG Kennedy, BW Kim, DH Klein, K Klier, A Kobayashi, T Kobel, M Kokott, TP Komamiya, S Kowalewski, RV Kress, T Krieger, P von Krogh, J Kuhl, T Kupper, M Kyberd, P Lafferty, GD Landsman, H Lanske, D Lauber, J Lawson, I Layter, JG Leins, A Lellouch, D Letts, J Levinson, L Liebisch, R Lillich, J List, B Littlewood, C Lloyd, AW Lloyd, SL Loebinger, FK Long, GD Losty, MJ Lu, J Ludwig, J Macchiolo, A Macpherson, A Mader, W Mannelli, M Marcellini, S Marchant, TE Martin, AJ Martin, JP Martinez, G Mashimo, T Mattig, P McDonald, WJ McKenna, J McMahon, TJ McPherson, RA Meijers, F Mendez-Lorenzo, P Merritt, FS Mes, H Michelini, A Mihara, S Mikenberg, G Miller, DJ Mohr, W Montanari, A Mori, T Nagai, K Nakamura, I Neal, HA Nisius, R O'Neale, SW Oakham, FG Odorici, F Ogren, HO Oh, A Okpara, A Oreglia, MJ Orito, S Pasztor, G Pater, JR Patrick, GN Patt, J Pfeifenschneider, P Pilcher, JE Pinfold, J Plane, DE Poli, B Polok, J Pooth, O Przybycien, M Quadt, A Rembser, C Rick, H Robins, SA Rodning, N Roney, JM Rosati, S Roscoe, K Rossi, AM Rozen, Y Runge, K Runolfsson, O Rust, DR Sachs, K Saeki, T Sahr, O Sarkisyan, EKG Sbarra, C Schaile, AD Schaile, O Scharff-Hansen, P Schmitt, S Schroder, M Schumacher, M Schwick, C Scott, WG Seuster, R Shears, TG Shen, BC Shepherd-Themistocleous, CH Sherwood, P Siroli, GP Skuja, A Smith, AM Snow, GA Sobie, R Soldner-Rembold, S Spagnolo, S Sproston, M Stahl, A Stephens, K Stoll, K Strom, D Strohmer, R Surrow, B Talbot, SD Tarem, S Taylor, RJ Teuscher, R Thiergen, M Thomas, J Thomson, MA Torrence, E Towers, S Trefzger, T Trigger, I Trocsanyi, Z Tsur, E Turner-Watson, MF Ueda, I Vannerem, P Verzocchi, M Voss, H Vossebeld, J Waller, D Ward, CP Ward, DR Ward, JJ Watkins, PM Watson, AT Watson, NK Wells, PS Wengler, T Wermes, N Wetterling, D White, JS Wilson, GW Wilson, JA Wyatt, TR Yamashita, S Zacek, V Zer-Zion, D

G. Abbiendi et al., Measurement of the low-x behaviour of the photon structure function F-2(gamma), EUR PHY J C, 18(1), 2000, pp. 15-39

74

INGLESE

Article

Physics

EUROPEAN PHYSICAL JOURNAL C

1434-6044 → ACNP

18

1

2000

15 - 39

ISI

1434-6044(200012)18:1<15:MOTLBO>2.0.ZU;2-1

The photon structure function F-2(gamma)(x, Q(2)) has been measured using d ata taken by the OPAL detector at e(+)e(-) centre-of-mass energies of 91 Ge V, 183 GeV and 189 GeV, in Q(2) ranges of 1.5-30.0 GeV2 (LEP1), and 7.0-30. 0 GeV2 (LEP2), probing lower values of x than ever before. Since previous O PAL analyses, new Monte Carlo models and new methods, such as multi-variabl e unfolding, have been introduced, reducing significantly the model depende nt systematic errors in the measurement. The results do not conclusively pr ove, but are completely consistent with, the presence of a rise in F-2(gamm a) at low-x as expected from QCD.