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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}
}
  • We establish improved upper limits on branching fractions for B{sup 0} decays to final states where the decay products are purely invisible (i.e., no observable final state particles) and for final states where the only visible product is a photon. Within the Standard Model, these decays have branching fractions that are below the current experimental sensitivity, but various models of physics beyond the Standard Model predict significant contributions for these channels. Using 471 million B{bar B} pairs collected at the {Upsilon} (4S) resonance by the BABAR experiment at the PEP-II e{sup +}e{sup -} storage ring at the SLAC National Acceleratormore » Laboratory, we establish upper limits at the 90% confidence level of 2.4 x 10{sup -5} for the branching fraction of B{sup 0} {yields} invisible and 1.7 x 10{sup -5} for the branching fraction of B{sup 0} {yields} invisible + {gamma}.« less
  • Cited by 5
  • We report the results of a new search for flavor-changing neutral-current decays of the b quark and present a 90%-confidence-level upper limit for the branching fraction for B..-->..l/sup +/l/sup -/X of 1.2 x 10/sup -3/.
  • The first limit on the branching ratio of the electric charge-nonconserving invisible muon decay Br({mu}{sup +}{yields}invisible)<5.2x10{sup -3} is obtained from the recently reported results on new determination of the Fermi constant from muon decays. The results of a feasibility study of a new proposed experiment for a sensitive search for this decay mode at the level of a few parts in 10{sup 11} are presented. Constrains on the {tau}{yields}invisible decay rate are discussed. These leptonic charge-nonconserving processes may hold in four-dimensional world in models with infinite extra dimensions, thus making their searches complementary to collider experiments probing new physics.
  • We search for invisible decays of the {Upsilon}(1S) meson using a sample of 91.4 x 10{sup 6} {Upsilon}(3S) mesons collected at the BABAR/PEP-II B Factory. We select events containing the decay {Upsilon}(3S) {yields} {pi}{sup +}{pi}{sup -} {Upsilon}(1S) and search for evidence of an undetectable {Upsilon}(1S) decay recoiling against the dipion system. We set an upper limit on the branching fraction {Beta}({Upsilon}(1S) {yields} invisible) < 3.0 x 10{sup ?4} at the 90% confidence level.