LINAC-LHC ep COLLIDER OPTIONS

We describe various parameter scenarios for a linac-ring ep collider based on LHC and an independent electron linac. Luminosities between 1031 and 1033 cm−2s−1 can be achieved with a s.c. linac, operated either pulsed or in cw mode with optional recirculation, at a total electric wall-plug power of order 20 MW. Higher luminosities of several 1033 cm−2s−1 can be reached by investing more electric power or by energy recovery. Finally, merits of a linac-ring ep collider are discussed. SCENARIOS Colliding the LHC 7-TeV protons with a 25–140 GeV e ± beam would both extend the discovery reach of the LHC, and enable precision physics with LHC data [1, 2]. e+p collisions are desirable in addition to e−p. One way to realize such ep collider is by installing a new lepton ring in the LHC tunnel, implying a new lepton injector too [3, 4]. The THERA study [5] inspired looks at an alter-native LHC-based “QCD Explorer ” colliding LHC protons with electrons delivered by a linac [6]. Possible linac-ring scenarios include a n.c. linac, a pulsed s.c. linac, and a cw s.c. linac with or without energy recovery in various configurations, as shown in Fig. 1. LHC sc or nc pulsed linac LHC sc cw lina