[e.sub.8] Mass limit (TeV) Proton colliders LHC 14 LHC 136 TeV, 500 TeV, 10 [fb.sup.-1] [ab.sup.-1] Electron colliders ILC 1 PWFA-LC 10 TeV, 10 TeV, 500 [fb.sup.-1] [fb.sup.-1] Electron-proton
colliders LHC x SppC LHC x SppC 11.78 TeV, 36.9 TeV, 10 1 [fb.sup.-1] [fb.sup.-1] Note: Table made from bar graph.
The maximum number of genuine electron-proton coincidences never amounted to more than a few per minute.
The second peak centred near channel 74 derives from genuine electron-proton coincidences.
Adopting the procedure recommended by the Particle Data Group  to deduce upper limits for Poisson processes when only a small number of events has been observed, this may be expressed in terms of the triple coincidence rate [N.sub.T] and the electron-proton coincidence rate [N.sub.D],
With an improved geometry approaching 4[pi] solid angle for proton detection we expect to improve the observed rate of electron-proton coincidence detection by two orders of magnitude .
However, VLEPP will be built at Serpukhov, so as to give the opportunity for eventually building connections to UNK and obtaining high-energy electron-proton
and positron-proton collisions.
The precision of the Electron-proton
coincidence given by (2) is smaller than 0.02%.
The experiment will make use of the existing apparatus for the NIST proton-trap lifetime experiment, which can provide substantial background reduction by providing an electron-proton coincidence trigger.
Initial measurements of the electron-proton coincidence rate while the proton-trap lifetime apparatus was last installed on NG-6 showed a total rate of 0.2 [s.sup.-1] with low backgrounds.
Optimization tests of the electron-proton coincidence setup are currently in progress using the cold neutron beam.
Let ep denote both electron-proton
and positron-proton interaction.
coincidence events are counted as a function of the neutron spin state to extract a measurement of D.