Experimental evidence for beam-beam disruption at the SLC

A significant luminosity enhancement from beam-beam disruption was observed for the first time during the 1997-98 run of the SLAC Linear Collider (SLC). Disruption, or pinch effect, is due to the decrease in effective beam size during collisions as each beam is focused by the field of the other beam. With beam intensities of 4.0 10/sup 10/ per bunch, bunch lengths of 1.1 mm, and horizontal and vertical beam sizes of /spl sigma//sub x/=1.5 /spl mu/m and /spl sigma//sub y/=0.65 /spl mu/m, the luminosity increase from disruption was more than 100%. Measured data rates as recorded by the SLD detector were in agreement with the theoretically calculated disruption enhancement.