We search for single-photon decays of the Upsilon(1S) resonance, Upsilon gamma + 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, chichi. Both A⁰ and chi are assumed to have zero spin. We tag Upsilon(1S) decays with a dipion transition Upsilon(2S) pi⁺pi⁻Upsilon(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 m(A⁰) ≤ 9.2 GeV and m(chi) ≤ 4.5 GeV in the sample of 98 * 10⁶ Upsilon(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 Upsilon(1S).
PALANO, Antimo;PAPPAGALLO, MARCO IGNAZIO;
2011-01-01
Abstract
We search for single-photon decays of the Upsilon(1S) resonance, Upsilon gamma + 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, chichi. Both A⁰ and chi are assumed to have zero spin. We tag Upsilon(1S) decays with a dipion transition Upsilon(2S) pi⁺pi⁻Upsilon(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 m(A⁰) ≤ 9.2 GeV and m(chi) ≤ 4.5 GeV in the sample of 98 * 10⁶ Upsilon(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.
