English

Measurement of Upper Limits for Upsilon to gamma + Resonance Decays

High Energy Physics - Experiment 2007-05-23 v3

Abstract

Motivated by concerns regarding possible two-body contributions to the recently-measured inclusive Υ\Upsilon(nS)γ+X\to\gamma+X direct photon spectrum, we report on a preliminary new study of exclusive radiative decays of the Υ\Upsilon resonances into two-body final states Rγ{\cal R}\gamma, with R{\cal R} some resonant hadronic state decaying into four or more charged particles. Such two-body processes are not explicitly addressed in the extant theoretical frameworks used to calculate the inclusive direct photon spectrum. Using data collected from the CLEO III detector at the Cornell Electron Storage Ring, we present upper limits for such Υ(1S)\Upsilon({\rm 1S}), Υ(2S)\Upsilon({\rm 2S}), and Υ(3S)\Upsilon({\rm 3S}) two-body decays as a function of the recoil mass MRM_{\cal R}. Additionally, we place upper limits on the cross-section for R{\cal R} production via radiative return for center-of-mass energies just below the Υ(1S)\Upsilon({\rm 1S}), Υ(2S)\Upsilon({\rm 2S}), and Υ(3S)\Upsilon({\rm 3S}) energies. The results presented in this document are preliminary.

Keywords

Cite

@article{arxiv.hep-ex/0607054,
  title  = {Measurement of Upper Limits for Upsilon to gamma + Resonance Decays},
  author = {J. Rosner and CLEO Collaboration},
  journal= {arXiv preprint arXiv:hep-ex/0607054},
  year   = {2007}
}

Comments

13 pages postscript,also available through http://www.lepp.cornell.edu/public/CONF/, Contributed to ICHEP06