ISSN - 00319007, EISSN - 10797114, Physical Review Letters, 2007, vol. 98, p. -
Search for invisible decay of the Υ(1S)
We report results of a search for the invisible decay of the Υ(1S) via the Υ(3S)→π+π-Υ(1S) transition using a data sample of 2.9fb-1 at the Υ(3S) resonance. The data were collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. No signal is found, and an upper limit for the branching fraction at the 90% confidence level is determined to be B(Υ(1S)→invisible)<2.5×10-3. © 2007 The American Physical Society.