Observation of hard scattering in photoproduction at HERA

Physics Letters B 297:3-4 (1992) 404-416

Authors:

M Derrick, D Krakauer, S Magill, B Musgrave, J Repond, K Sugano, R Stanek, RL Talaga, J Thron, F Arzarello, R Ayed, G Barbagli, G Bari, M Basile, L Bellagamba, D Boscherini, G Bruni, P Bruni, G Cara Romeo, G Castellini, M Chiarini, L Cifarelli, F Cindolo, F Ciralli, A Contin, S D'Auria, C Del Papa, F Frasconi, P Giusti, G Iacobucci, G Laurenti, G Levi, Q Lin, B Lisowski, G Maccarrone, A Margotti, T Massam, R Nania, C Nemoz, F Palmonari, G Sartorelli, R Timellini, Y Zamora Garcia, A Zichichi, A Bargende, F Barreiro, J Crittenden, H Dabbous, K Desch, B Diekmann, M Geerts, G Geitz, B Gutjahr, H Hartmann, J Hartmann, D Haun, K Heinloth, E Hilger, HP Jakob, S Kramarczyk, M Kückes, A Mass, S Mengel, J Mollen, H Müsch, E Paul, R Schattevoy, B Schneider, JL Schneider, R Wedemeyer, A Cassidy, DG Cussans, N Dyce, HF Fawcett, B Foster, R Gilmore, GP Heath, M Lancaster, TJ Llewellyn, J Malos, CJS Morgado, RJ Tapper, SS Wilson, RR Rau, A Bernstein, A Caldwell, I Gialas, JA Parsons, S Ritz, F Sciulli, PB Straub, L Wai, S Yang, T Barillari, M Schioppa, G Susinno, W Burkot, J Chwastowski, A Dwuraźny, A Eskreys

Abstract:

We report a study of electron proton collisions at very low Q2, corresponding to virtual photoproduction at centre of mass energies in the range 100-295 GeV. The distribution in transverse energy of the observed hadrons is much harder than can be explained by soft processes. Some of the events show back-to-back two-jet production at the rate and with the characteristics expected from hard two-body scattering. A subset of the two-jet events have energy in the electron direction consistent with that expected from the photon remnant in resolved photon processes. © 1992.

A measurement of σtot(γp) at S = 210 GeV

Physics Letters B 293:3-4 (1992) 465-477

Authors:

M Derrick, D Krakauer, S Magill, B Musgrave, J Repond, K Sugano, R Stanek, RL Talaga, J Thron, F Arzarello, R Ayed, G Barbagli, G Bari, M Basile, L Bellagamba, D Boscherini, G Bruni, P Bruni, GC Romeo, G Castellini, M Chiarini, L Cifarelli, F Cindolo, F Ciralli, A Contin, S D'Auria, C Del Papa, F Frasconi, P Giusti, G Iacobucci, G Laurenti, G Levi, Q Lin, B Lisowski, G Maccarrone, A Margotti, T Massam, R Nania, C Nemoz, F Palmonari, G Sartorelli, R Timellini, Y Zamora Garcia, A Zichichi, A Bargende, F Barreiro, J Crittenden, H Dabbous, K Desch, B Diekmann, M Geerts, G Geitz, B Gutjahr, H Hartmann, J Hartmann, D Haun, K Heinloth, E Hilger, HP Jakob, S Kramarczyk, M Kückes, A Mass, S Mengel, J Mollen, H Müsch, E Paul, R Schattevoy, B Schneider, JL Schneider, R Wedemeyer, A Cassidy, DG Cussans, N Dyce, HF Fawcett, B Foster, R Gilmore, GP Heath, M Lancaster, TJ Llewellyn, J Malos, CJS Morgado, RJ Tapper, SS Wilson, RR Rau, A Bernstein, A Caldwell, I Gialas, JA Parsons, S Ritz, F Sciulli, PB Straub, L Wai, S Yang, T Barillari, M Schioppa, G Susinno, W Burkot, J Chwastowski, A Dwuraźny, A Eskreys

Abstract:

The total photoproduction cross section is determined from a measurement of electroproduction with the ZEUS detector at HERA. The Q2 values of the virtual photons are in the range 10-7

1ST AND 2ND LEVEL TRIGGERS FOR THE SDC SILICON TRACKING DETECTOR

NUCL INSTRUM METH A 315:1-3 (1992) 436-442

Authors:

B FOSTER, GP HEATH, R NICKERSON

First and second level triggers for the SDC silicon tracking detector

Nuclear Inst. and Methods in Physics Research, A 315:1-3 (1992) 436-442

Authors:

B Foster, GP Heath, R Nickerson

Abstract:

Some preliminary design ideas for contributions to the first and second level trigger from the inner silicon tracker of SDC experiment at the Superconducting Super Collider (SSC) are outlined. At the first level it is possible to design a trigger which can recognise isolated tracks, measure their momentum and link these tracks to energy deposits in the electromagnetic calorimeter. This could therefore form a powerful isolated lepton trigger. At the second level we describe ideas for a general purpose trigger which is capable of recognising high transverse momentum tracks in both the barrel and end-cap. By means of a two-stage analysis it is possible to measure track momentum with the full precision of the silicon tracker. © 1992.

THE DESIGN, STATUS AND PERFORMANCE OF THE ZEUS CENTRAL TRACKING DETECTOR ELECTRONICS

NUCL INSTRUM METH A 315:1-3 (1992) 397-403

Authors:

DG CUSSANS, HF FAWCETT, B FOSTER, RS GILMORE, GP HEATH, TJ LLEWELLYN, J MALOS, CJS MORGADO, RJ TAPPER, DM GINGRICH, N HARNEW, P HALLAMBAKER, J NASH, T KHATRI, PD SHIELD, I MCARTHUR, S TOPPJORGENSEN, FF WILSON, D ALLEN, SA BAIRD, R CARTER, S GALAGADERA, MD GIBSON, RS HATLEY, M JEFFS, R MILBORROW, M MORISSEY, SPH QUINTON, DJ WHITE, J LANE, G NIXON, M POSTRANECKY, AK JAMDAGNI, C MARCOU, DB MILLER, L TOUDUP