Neutral pion decays probe new physics beyond the standard model

Dobroliubov, M.I.; Ignatiev, A. Yu.

doi:10.1016/0550-3213(88)90334-3

Cited by 20 publications

(17 citation statements)

References 14 publications

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“…Therefore, a positive result in the direct search for these decay modes could be interpreted unambiguously as the discovery of a new light spin 1 particle, in contrast with other experiments searching for light weakly interacting particles in rare K, π or µ decays [5,6].…”

Section: Introductionmentioning

confidence: 99%

“…If the mass M X is of the order of the pion mass, an effective search could be conducted for this new vector boson in the radiative decays of neutral pseudoscalar mesons P → γ + X, where P = π 0 , η, or η ′ , because the decay rate of P → γ + any new particles with spin 0 or 1 2 proves to be negligibly small [5]. Therefore, a positive result in the direct search for these decay modes could be interpreted unambiguously as the discovery of a new light spin 1 particle, in contrast with other experiments searching for light weakly interacting particles in rare K, π or µ decays [5,6].…”

Section: Introductionmentioning

confidence: 99%

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Search for a new gauge boson in π0 decays

et al. 1998

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A search was made for a new light gauge boson X which might be produced in π 0 → γ + X decay from neutral pions generated by 450-GeV protons in the CERN SPS neutrino target. The X's would penetrate the downstream shielding and be observed in the NOMAD detector via the Primakoff effect, in the process of X → π 0 conversion in the external Coulomb field of a nucleus. With 1.45×10 18 protons on target, 20 candidate events with energy between 8 and 140 GeV were found from the analysis of neutrino data. This number is in agreement with the expectation of 18.1±2.8 background events from standard neutrino processes. A new 90 % C.L. upper limit on the branching ratio Br(π 0 → γ + X) < (3.3 to 1.9)×10 −5 for X masses ranging from 0 to 120 MeV/c 2 is obtained.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Search for a new gauge boson in π0 decays

et al. 1998

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“…If this is the case, it would suggest the existence of X bosons with J P of either 0 + or 1 − to conserve angular momentum and parity, consistent with the conclusion of the (g − 2) considerations outlined above. While theoretical limits have been placed on the decay π 0 → γ + X [52], a potential π 0 → 2X, X → e + e − channel was not considered, and the fraction of apparent π 0 → e + e − e + e − decays that may proceed through X-boson intermediaries is unknown. It is interesting in this regard that a significant peak at about 10 MeV/c 2 in the e + e − spectrum from η decay has been reported by the CLEO Collaboration ( Fig.…”

Section: Discussionmentioning

confidence: 99%

A Reevaluation of Evidence for Light Neutral Bosons in Nuclear Emulsions

Boer¹,

Fields

2011

Int. J. Mod. Phys. E

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Electron-positron pair-production data obtained by bombardment of emulsion detectors with either cosmic rays or projectiles with masses between one and 207 amu and kinetic energies between 18 GeV and 32 TeV have been re-analysed using a consistent and conservative model of the background from electromagnetic pair conversion. The combined data yield a spectrum of putative neutral bosons decaying to e + e − pairs, with masses between 3 and 20 MeV/c 2 and femtosecond lifetimes. The statistical significance against background for these "X-bosons" varies between 2 and 8 σ. The cross-section for direct production of X-bosons increases slowly with projectile energy, remaining over 1,000 times smaller than the pion production cross-section. * Deceased

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“…Using Eqs. (5,6) we can determine the 90% C.L. exclusion regions in the (M V ; χ) plane from the results of the NO-MAD [22] and PS191 [20] experiments, which are shown in Fig.…”

Section: Many Extensions Of the Standard Model (Sm) Such Asmentioning

confidence: 99%

Stringent limits on theπ0→γX,X→e+e−decay from neutrino experiments and constraints on new l

Gninenko

2012

Phys. Rev. D

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We report new limits on the 0 ! X decay of the neutral pion into a photon and a new gauge boson X followed by the decay X ! e þ e À . If this process exists, one would expect a flux of high energy X's produced from 0 's generated by the proton beam in a neutrino target. The X's would then penetrate the downstream shielding and be observed in a neutrino detector via their decays. Using bounds from the NOMAD and PS191 neutrino experiments at CERN that searched for an excess of e þ e À pairs from heavy neutrino decays, stringent limits on the branching ratio as small as Brð 0 ! XÞ & 10 À15 are obtained. These limits are several orders of magnitude smaller than the previous experimental and cosmological bounds. The obtained results are used to constrain models, where the X interacts with quarks and leptons, or it is a new vector boson mixing with photons that transmits interaction between our world and hidden sectors consisting of SUð3Þ C Â SUð2Þ L Â Uð1Þ Y singlet fields.

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Neutral pion decays probe new physics beyond the standard model

Cited by 20 publications

References 14 publications

Search for a new gauge boson in π0 decays

Search for a new gauge boson in π0 decays

A Reevaluation of Evidence for Light Neutral Bosons in Nuclear Emulsions

Stringent limits on theπ0→γX,X→e+e−decay from neutrino experiments and constraints on new l

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