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 the βy∗ (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.
@article{arxiv.physics/0011075,
title = {Novel Method of Measuring Electron Positron Colliding Beam Parameters},
author = {D. Cinabro and K. Korbiak and R. Ehrlich and S. Henderson and N. Mistry},
journal= {arXiv preprint arXiv:physics/0011075},
year = {2009}
}