We search for single-photon decays of the Υ(1S) resonance, Υ→γ+invisible, where the invisible state is either a particle of definite mass, such as a light Higgs boson A0, or a pair of dark matter particles, χχ̅ . Both A0 and χ are assumed to have zero spin. We tag Υ(1S) decays with a dipion transition Υ(2S)→π+π-Υ(1S) and look for events with a single energetic photon and significant missing energy. We find no evidence for such processes in the mass range mA0≤9.2 GeV and mχ≤4.5 GeV in the sample of 98×106 Υ(2S) decays collected with the BABAR detector and set stringent limits on new physics models that contain light dark matter states.
Search for Production of Invisible Final States in Single-Photon Decays of Υ(1S)
LO VETERE, MAURIZIO;MONGE, MARIA ROBERTA;PATRIGNANI, CLAUDIA;TOSI, SILVANO;
2011-01-01
Abstract
We search for single-photon decays of the Υ(1S) resonance, Υ→γ+invisible, where the invisible state is either a particle of definite mass, such as a light Higgs boson A0, or a pair of dark matter particles, χχ̅ . Both A0 and χ are assumed to have zero spin. We tag Υ(1S) decays with a dipion transition Υ(2S)→π+π-Υ(1S) and look for events with a single energetic photon and significant missing energy. We find no evidence for such processes in the mass range mA0≤9.2 GeV and mχ≤4.5 GeV in the sample of 98×106 Υ(2S) decays collected with the BABAR detector and set stringent limits on new physics models that contain light dark matter states.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.