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Title: Improved limit on invisible decays of positronium

Abstract

The results of a new search for positronium decays into invisible final states are reported. Convincing detection of this decay mode would be a strong evidence for new physics beyond the standard model (SM): for example, the existence of extra-dimensions, of milli-charged particles, of new light gauge bosons or of mirror particles. Mirror matter could be a relevant dark matter candidate. In this paper the setup and the results of a new experiment are presented. In a collected sample of about (6.31{+-}0.28)x10{sup 6} orthopositronium decays, no evidence for invisible decays in an energy [0,80] keV was found and an upper limit on the branching ratio of orthopositronium o-Ps{yields}invisible could be set: Br(o-Ps{yields}invisible)<4.2x10{sup -7}(90%C.L.) Our results provide a limit on the photon mirror-photon mixing strength {epsilon}{<=}1.55x10{sup -7}(90%C.L.) and rule out particles lighter than the electron mass with a fraction Q{sub x}{<=}3.4x10{sup -5} of the electron charge. Furthermore, upper limits on the branching ratios for the decay of parapositronium Br(p-Ps{yields}invisible){<=}4.3x10{sup -7}(90%C.L.) and the direct annihilation Br(e{sup +}e{sup -}{yields}invisible){<=}2.1x10{sup -8}(90%C.L.) could be set.

Authors:
; ; ; ;  [1]; ; ;  [2];  [3]
  1. ETH Zuerich, Zurich (Switzerland)
  2. Inst. Nucl. Research, INR Moscow (Russian Federation)
  3. Laboratoire Physique des Particules Annecy, LAPP (France)
Publication Date:
OSTI Identifier:
21010968
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 75; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevD.75.032004; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ANNIHILATION; BRANCHING RATIO; DECAY; ELECTRON-POSITRON INTERACTIONS; ELECTRONS; KEV RANGE; LIMITING VALUES; NONLUMINOUS MATTER; PARTICLE IDENTIFICATION; PHOTONS; POSITRONIUM; POSITRONS; REST MASS; STANDARD MODEL

Citation Formats

Badertscher, A., Crivelli, P., Fetscher, W., Gendotti, U., Rubbia, A., Gninenko, S. N., Postoev, V., Samoylenko, V., and Sillou, D. Improved limit on invisible decays of positronium. United States: N. p., 2007. Web. doi:10.1103/PHYSREVD.75.032004.
Badertscher, A., Crivelli, P., Fetscher, W., Gendotti, U., Rubbia, A., Gninenko, S. N., Postoev, V., Samoylenko, V., & Sillou, D. Improved limit on invisible decays of positronium. United States. doi:10.1103/PHYSREVD.75.032004.
Badertscher, A., Crivelli, P., Fetscher, W., Gendotti, U., Rubbia, A., Gninenko, S. N., Postoev, V., Samoylenko, V., and Sillou, D. Thu . "Improved limit on invisible decays of positronium". United States. doi:10.1103/PHYSREVD.75.032004.
@article{osti_21010968,
title = {Improved limit on invisible decays of positronium},
author = {Badertscher, A. and Crivelli, P. and Fetscher, W. and Gendotti, U. and Rubbia, A. and Gninenko, S. N. and Postoev, V. and Samoylenko, V. and Sillou, D.},
abstractNote = {The results of a new search for positronium decays into invisible final states are reported. Convincing detection of this decay mode would be a strong evidence for new physics beyond the standard model (SM): for example, the existence of extra-dimensions, of milli-charged particles, of new light gauge bosons or of mirror particles. Mirror matter could be a relevant dark matter candidate. In this paper the setup and the results of a new experiment are presented. In a collected sample of about (6.31{+-}0.28)x10{sup 6} orthopositronium decays, no evidence for invisible decays in an energy [0,80] keV was found and an upper limit on the branching ratio of orthopositronium o-Ps{yields}invisible could be set: Br(o-Ps{yields}invisible)<4.2x10{sup -7}(90%C.L.) Our results provide a limit on the photon mirror-photon mixing strength {epsilon}{<=}1.55x10{sup -7}(90%C.L.) and rule out particles lighter than the electron mass with a fraction Q{sub x}{<=}3.4x10{sup -5} of the electron charge. Furthermore, upper limits on the branching ratios for the decay of parapositronium Br(p-Ps{yields}invisible){<=}4.3x10{sup -7}(90%C.L.) and the direct annihilation Br(e{sup +}e{sup -}{yields}invisible){<=}2.1x10{sup -8}(90%C.L.) could be set.},
doi = {10.1103/PHYSREVD.75.032004},
journal = {Physical Review. D, Particles Fields},
number = 3,
volume = 75,
place = {United States},
year = {Thu Feb 01 00:00:00 EST 2007},
month = {Thu Feb 01 00:00:00 EST 2007}
}