Observation of hard scattering in photoproduction events with a large rapidity gap at HERA

Events with a large rapidity gap and total transverse energy greater than 5 GeV have been observed in quasi-real photoproduction at HERA with the ZEUS detector. The distribution of these events as a function of the $\gamma p$ centre of mass energy is consistent with diffractive scattering. For total transverse energies above 12 GeV, the hadronic final states show predominantly a two-jet structure with each jet having a transverse energy greater than 4 GeV. For the two-jet events, little energy flow is found outside the jets. This observation is consistent with the hard scattering of a quasi-real photon with a colourless object in the proton.Comment: 19 pages, latex, 4 figures appended as uuencoded fil

A Simplified Suction System for an HLFC Leading Edge Box of an A320 Fin

Wind tunnel and flight tests have clearly demonstrated the potential of hybrid laminar flow control (HLFC) for drag reduction. Additional weight and costs of the suction system reduce the efficiency of the HLFC technology. Within the EC funded ALTTA programme a drastically simplified suction system has been proposed. Characteristic of this system is one single suction duct, the leading edge box itself, a double sheet suction surface with suction velocity control by orifices in the inner sheet and a constant speed suction pump directly with the leading edge box. The system is optimised for the design conditions of the aircraft at cruise. Investigations at design and off-design conditions reveal that the simplified system would operate as required within sufficient ranges of all parameters investigated