Novel method of measuring electron positron colliding beam parameters

Through the simultaneous measurement of the transverse size as a function of longitudinal position, and the longitudinal distribution of luminosity, we are able to measure βy* (the vertical envelope function at the collision point), vertical emittance, and bunch length of colliding beams at the Cornell Electron–positron Storage Ring (CESR). This measurement is possible due to the significant “hourglass” effect at CESR and the excellent tracking resolution of the CLEO detector.