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.
Publication Source (Journal or Book title)
Physics Letters B
Derrick, M., Krakauer, D., Magill, S., Musgrave, B., Repond, J., Sugano, K., Stanek, R., Talaga, R., Thron, J., Arzarello, F., Ayed, R., Barbagli, G., Bari, G., Basile, M., Bellagamba, L., Boscherini, D., Bruni, G., Bruni, P., Cara Romeo, G., Castellini, G., Chiarini, M., Cifarelli, L., Cindolo, F., Ciralli, F., Contin, A., D'Auria, S., Del Papa, C., Frasconi, F., Giusti, P., Iacobucci, G., Laurenti, G., Levi, G., & Lin, Q. (1992). Observation of hard scattering in photoproduction at HERA. Physics Letters B, 297 (3-4), 404-416. https://doi.org/10.1016/0370-2693(92)91280-M