Measurement of the diffractive structure function in deep inelastic scattering at HERA

Zeitschrift für Physik C Particles and Fields 68:4 (1995) 569-584

Authors:

M Derrick, D Krakauer, S Magill, D Mikunas, B Musgrave, J Repond, R Stanek, RL Talaga, H Zhang, R Ayad, G Bari, M Basile, L Bellagamba, D Boscherini, A Bruni, G Bruni, P Bruni, G Cara Romeo, G Castellini, M Chiarini, L Cifarelli, F Cindolo, A Contin, M Corradi, I Gialas, P Giusti, G Iacobucci, G Laurenti, G Levi, A Margotti, T Massam, R Nania, C Nemoz, F Palmonari, A Polini, G Sartorelli, R Timellini, Y Zamora Garcia, A Zichichi, A Bargende, J Crittenden, K Desch, B Diekmann, T Doeker, M Eckert, L Feld, A Frey, M Geerts, G Geitz, M Grothe, H Hartmann, H Heinloth, E Hilger, HP Jakob, UF Katz, SM Mari, A Mass, S Mengel, J Mollen, E Paul, C Rembser, D Schramm, J Stamm, R Wedemeyer, S Campbell-Robson, A Cassidy, N Dyce, B Foster, S George, R Gilmore, GP Heath, HF Heath, TJ Llewellyn, CJS Morgado, DJP Norman, JA O'Mara, RJ Tapper, SS Wilson, R Yoshida, RR Rau, M Arneodo, M Capua, A Garfagnini, L Iannotti, M Schioppa, G Susinno, A Bernstein, A Caldwell, N Cartiglia, JA Parsons, S Ritz, F Sciulli, PB Straub, L Wai, S Yang, Q Zhu, P Borzemski, J Chwastowski, A Eskreys, K Piotrzkowski

Abstract:

This paper presents an analysis of the inclusive properties of diffractive deep inelastic scattering events produced in ep interactions at HERA. The events are characterised by a rapidity gap between the outgoing proton system and the remaining hadronic system. Inclusive distributions are presented and compared with Monte Carlo models for diffractive processes. The data are consistent with models where the pomeron structure function has a hard and a soft contribution. The diffractive structure function is measured as a function of xℙ, the momentum fraction lost by the proton, of β, the momentum fraction of the struck quark with respect to xℙ, and of Q2 in the range 6.3·10-4

Measurement of the proton structure function F 2 at low x and low Q 2 at HERA

Zeitschrift fur Physik C-Particles and Fields 69:1 (1995) 607-620

Authors:

M Derrick, D Krakauer, S Magill, D Mikunas, B Musgrave, J Repond, R Stanek, RL Talaga, H Zhang, G Bari, M Basile, L Bellagamba, D Boscherini, A Bruni, G Bruni, P Bruni, G Cara Romeo, G Castellini, M Chiarini, L Cifarelli, F Cindolo, A Contin, M Corradi, I Gialas, P Giusti, G Iacobucci, G Laurenti, G Levi, A Margotti, T Massam, R Nania, C Nemoz, F Palmonari, A Polini, G Sartorelli, R Timellini, Y Zamora Garcia, A Zichichi, A Bornheim, J Crittenden, K Desch, B Diekmann, T Doeker, M Eckert, L Feld, A Frey, M Geerts, M Grothe, H Hartmann, K Heinloth, L Heinz, E Hilger, HP Jakob, UF Katz, S Mengel, J Mollen, E Paul, M Pfeiffer, C Rembser, D Schramm, J Stamm, R Wedemeyer, S Campbell-Robson, A Cassidy, WN Cottingham, N Dyce, B Foster, S George, ME Hayes, GP Heath, HF Heath, CJS Morgado, JA O'Mara, D Piccioni, DG Roff, RJ Tapper, R Yoshida, RR Rau, M Arneodo, R Ayad, M Capua, A Garfagnini, L Iannotti, M Schioppa, G Susinno, A Bernstein, A Caldwell, N Cartiglia, JA Parsons, S Ritz, F Sciulli, PB Straub, L Wai, S Yang, Q Zhu, P Borzemski, J Chwastowski, A Eskreys, K Piotrzkowski, M Zachara

Abstract:

We report on a measurement of the proton structure function F 2 in the range 3.5×10-5≤x≤4×10-3 and 1.5 GeV2≤Q 2≤15GeV2 at the ep collider HERA operating at a centre-of-mass energy of √s=300GeV. The rise of F 2 with decreasing x observed in the previous HERA measurements persists in this lower x and Q 2 range. The Q 2 evolution of F 2, even at the lowest Q 2 and x measured, is consistent with perturbative QCD. © 1996 Springer-Verlag.

Measurement of αsfrom jet rates in deep inelastic scattering at HERA

Physics Letters B 363:3 (1995) 201-216

Authors:

M Derrick, D Krakauer, S Magill, D Mikunas, B Musgrave, J Repond, R Stanek, RL Talaga, H Zhang, R Ayad, G Bari, M Basile, L Bellagamba, D Boscherini, A Bruni, G Bruni, P Bruni, G Cara Romeo, G Castellini, M Chiarini, L Cifarelli, F Cindolo, A Contin, M Corradi, I Gialas, P Giusti, G Iacobucci, G Laurenti, G Levi, A Margotti, T Massam, R Nania, C Nemoz, F Palmonari, A Polini, G Sartorelli, R Timellini, Y Zamora Garcia, A Zichichi, A Bargende, A Bornheim, J Crittenden, K Desch, B Diekmann, T Doeker, M Eckert, L Feld, A Frey, M Geerts, M Grothe, H Hartmann, K Heinloth, E Hilger, HP Jakob, UF Katz, S Mengel, J Mollen, E Paul, M Pfeiffer, C Rembser, D Schramm, J Stamm, R Wedemeyer, S Campbell-Robson, A Cassidy, WN Cottingham, N Dyce, B Foster, S George, ME Hayes, GP Heath, HF Heath, CJS Morgado, JA O'Mara, D Piccioni, DG Roff, RJ Tapper, R Yoshida, RR Rau, M Arneodo, M Capua, A Garfagnini, L Iannotti, M Schioppa, G Susinno, A Bernstein, A Caldwell, N Cartiglia, JA Parsons, S Ritz, F Sciulli, PB Straub, L Wai, S Yang, Q Zhu, P Borzemski, J Chwastowski, A Eskreys, K Piotrzkowski, M Zachara

Abstract:

Jet production in deep inelastic scattering for 120 < Q2< 3600 GeV2has been studied using data from an integrated luminosity of 3.2 pb-1collected with the ZEUS detector at HERA. Jets are identified with the JADE algorithm. A cut on the angular distribution of parton emission in the γ*-parton centre-of-mass system minimises the experimental and theoretical uncertainties in the determination of the jet rates. The jet rates, when compared to O(αs2) perturbative QCD calculations, allow a precise determination of αs(Q) in three Q2-intervals. The values are consistent with a running of ifαs(Q), as expected from QCD. Extrapolating to Q = MZ0αs(MZ0) = 0.117 ± 0.005 (stat)-0.005+0.004(systexp) ± 0.007 (systtheory). © 1995.

Measurement of the proton structure function F2 from the 1993 HERA data

Zeitschrift für Physik C Particles and Fields 65:3 (1995) 379-398

Authors:

M Derrick, D Krakauer, S Magill, B Musgrave, J Repond, J Schlereth, R Stanek, RL Talaga, J Thron, F Arzarello, R Ayad, G Bari, M Basile, L Bellagamba, D Boscherini, A Bruni, G Bruni, P Bruni, G Cara Romeo, G Castellini, M Chiarini, L Cifarelli, F Cindolo, F Ciralli, A Contin, S D'Auria, F Frasconi, P Giusti, G Iacobucci, G Laurenti, G Levi, A Margotti, T Massam, R Nania, C Nemoz, F Palmonari, A Polini, G Sartorelli, R Timellini, Y Zamora Garcia, A Zichichi, A Bargende, J Crittenden, K Desch, B Diekmann, T Doeker, L Feld, A Frey, M Geerts, G Geitz, M Grothe, H Hartmann, D Haun, K Heinloth, E Hilger, HP Jakob, UF Katz, SM Mari, A Mass, S Mengel, J Mollen, E Paul, C Rembser, R Schattevoy, JL Schneider, D Schramm, J Stamm, R Wedemeyer, S Campbell-Robson, A Cassidy, N Dyce, B Foster, S George, R Gilmore, GP Heath, HF Heath, TJ Llewellyn, CJS Morgado, DJP Norman, JA O'Mara, RJ Tapper, SS Wilson, R Yoshida, RR Rau, M Arneodo, L Iannotti, M Schioppa, G Susinno, A Bernstein, A Caldwell, I Gialas, JA Parsons, S Ritz, F Sciulli, PB Straub, L Wai, S Yang, P Borzemski, J Chwastowski, A Eskreys

Abstract:

The ZEUS detector has been used to measure the proton structure function F2. During 1993 HERA collided 26.7 GeV electrons on 820 GeV protons. The data sample corresponds to an integrated luminosity of 0.54 pb-1, representing a twenty fold increase in statistics compared to that of 1992. Results are presented for 7

Exclusive ϱ0 production in deep inelastic electron-proton scattering at HERA

Physics Letters B 356:4 (1995) 601-616

Authors:

M Derrick, D Krakauer, S Magill, D Mikunas, B Musgrave, J Repond, R Stanek, RL Talaga, H Zhang, R Ayad, G Bari, M Basile, L Bellagamba, D Boscherini, A Bruni, G Bruni, P Bruni, G Cara Romeo, G Castellini, M Chiarini, L Cifarelli, F Cindolo, A Contin, M Corradi, I Gialas, P Giusti, G Iacobucci, G Laurenti, G Levi, A Margotti, T Massam, R Nania, C Nemoz, F Palmonari, A Polini, G Sartorelli, R Timellini, Y Zamora Garcia, A Zichichi, A Bargende, J Crittenden, K Desch, B Diekmann, T Doeker, M Eckert, L Feld, A Frey, M Geerts, M Grothe, H Hartmann, K Heinloth, E Hilger, HP Jakob, UF Katz, SM Mari, S Mengel, J Mollen, E Paul, M Pfeiffer, C Rembser, D Schramm, J Stamm, R Wedemeyer, S Campbell-Robson, A Cassidy, N Dyce, B Foster, S George, R Gilmore, GP Heath, HF Heath, TJ Llewellyn, CJS Morgado, DJP Norman, JA O'Mara, RJ Tapper, SS Wilson, R Yoshida, RR Rau, M Arneodo, M Capua, A Garfagnini, L Iannotti, M Schioppa, G Susinno, A Bernstein, A Caldwell, N Cartiglia, JA Parsons, S Ritz, F Sciulli, PB Straub, L Wai, S Yang, Q Zhu, P Borzemski, J Chwastowski, A Eskreys, K Piotrzkowski, M Zachara

Abstract:

The exclusive production of ρ{variant}0mesons in deep inelastic electron-proton scattering has been studied using the ZEUS detector. Cross sections have been measured in the range 7 < Q2< 25 GeV2for λ*p centre of mass (c.m.) energies 40 to 130 GeV. The λ*p → ρ{variant}0p cross section exhibits a Q-(4.2±0.8-0.5+1.4)dependence and both longitudinally and transversely polarised ρ{variant}0's are observed. The λ*p → ρ{variant}0p cross section rises strongly with increasing c.m. energy, when compared with NMC data at lower energy, which cannot be explained by production through soft pomeron exchange. The data are compared with perturbative QCD calculations where the rise in the cross section reflects the increase in the gluon density at low x. © 1995.