LUMINOSITY SPECTRUM MEASUREMENT IN FUTURE E(-) LINEAR COLLIDERS USINGLARGE-ANGLE BHABHA EVENTS()E()

In future e(+)e(-) linear colliders, the colliding energy cannot be mo nochromatic due to the large effect of beam-beam interactions before e (+)e(-) collisions. The luminosity must have a continuous spectrum whi ch distributes around the nominal energy and has a long tail toward th e low-energy region. An accurate measurement of the luminosity spectru m is indispensable for a precise experiment at high-luminosity e(+)e(- ) linear colliders. It has been found that the luminosity spectrum can be determined by measuring the acollinearity angle of Bhabha events b y a tracking device with good angular resolution. The beam parameters, i.e. the beam-energy spread, the topological beam size and the number of particles in a beam bunch, can be also extracted from the measured luminosity spectrum by a likelihood fitting. (C) 1998 Elsevier Scienc e B.V. All rights reserved.