| Decay | Limit at 90% CL x106 | Experiment | Reference |
|---|
|
| γγ | 26.0 | CLEO II | T.E. Coan et al., Phys. Rev. Lett. 90 (2003) 101801 |
| 3.8 | BESIII | M. Ablikim et al., Phys. Rev. D91 (2015) 112015 |
| 2.2 | BaBar | J.P. Lees et al., Phys. Rev. D85 (2012) 091107 |
| 0.85 | Belle | N.K. Nisar et al., Phys. Rev. D93 (2016) 051102 |
|
| e+e- | 220.0 | CLEO | P. Haas et al., Phys. Rev. Lett. 60 (1988) 1614 |
| 170.0 | Argus | H. Albrecht et al., Phys. Lett. B209 (1988) 380 |
| 130.0 | Mark3 | J. Adler et al., Phys. Rev. D37 (1988) 2023 |
| 13.0 | CLEO II | A. Freyberger et al., Phys. Rev. Lett. 76 (1996) 3065 |
| 8.19 | E789 | D. Pripstein et al., Phys. Rev. D61 (2000) 032005 |
| 6.2 | E791 | E.M. Aitala et al., Phys. Lett. B462 (1999) 401 |
| 1.2 | BaBar | B. Aubert et al., Phys. Rev. Lett. 93 (2004) 191801 |
| 0.079 | Belle | M. Petric et al., Phys. Rev. D81 (2010) 091102R |
|
| μ+μ- | 70.0 | Argus | H. Albrecht et al., Phys. Lett. B209 (1988) 380 |
| 44.0 | E653 | K. Kodama et al., Phys. Lett. B345 (1995) 85 |
| 34.0 | CLEO II | A. Freyberger et al., Phys. Rev. Lett. 76 (1996) 3065 |
| 15.6 | E789 | D. Pripstein et al., Phys. Rev. D61 (2000) 032005 |
| 5.2 | E791 | E.M. Aitala et al., Phys. Lett. B462 (1999) 401 |
| 2.0 | HERAb | I. Abt et al., Phys. Lett. B596 (2004) 173 |
| 1.3 | BaBar | B. Aubert et al., Phys. Rev. Lett. 93 (2004) 191801 |
| 0.21 | CDF | T. Aaltonen et al., Phys. Rev. D82 (2010) 091105R |
| 0.14 | Belle | M. Petric et al., Phys. Rev. D81 (2010) 091102R |
| 0.0062 | LHCb | R. Aaij et al., Phys.Lett. B725 (2013) 15 |
|
| π0e+e- | 45.0 | CLEO II | A. Freyberger et al., Phys. Rev. Lett. 76 (1996) 3065 |
|
| π0μ+μ- | 540.0 | CLEO II | A. Freyberger et al., Phys. Rev. Lett. 76 (1996) 3065 |
| 180.0 | E653 | K. Kodama et al., Phys. Lett. B345 (1995) 85 |
|
| ηe+e- | 110.0 | CLEO II | A. Freyberger et al., Phys. Rev. Lett. 76 (1996) 3065 |
|
| ημ+μ- | 530.0 | CLEO II | A. Freyberger et al., Phys. Rev. Lett. 76 (1996) 3065 |
|
| π+π-e+e- | 370.0 | E791 | E.M. Aitala et al., Phys. Rev. Lett. 86 (2001) 3969 |
|
| ρ0e+e- | 450.0 | CLEO | P. Haas et al., Phys. Rev. Lett. 60 (1988) 1614 |
| 124.0 | E791 | E.M. Aitala et al., Phys. Rev. Lett. 86 (2001) 3969 |
| 100.0 | CLEO II | A. Freyberger et al., Phys. Rev. Lett. 76 (1996) 3065 |
|
| π+π-μ+μ- | 30.0 | E791 | E.M. Aitala et al., Phys. Rev. Lett. 86 (2001) 3969 |
| 0.55 | LHCb | R. Aaij et al., Phys.Lett. B728 (2014) 234 |
|
| ρ0μ+μ- | 810.0 | CLEO | P. Haas et al., Phys. Rev. Lett. 60 (1988) 1614 |
| 490.0 | CLEO II | A. Freyberger et al., Phys. Rev. Lett. 76 (1996) 3065 |
| 230.0 | E653 | K. Kodama et al., Phys. Lett. B345 (1995) 85 |
| 22.0 | E791 | E.M. Aitala et al., Phys. Rev. Lett. 86 (2001) 3969 |
|
| ωe+e- | 180.0 | CLEO II | A. Freyberger et al., Phys. Rev. Lett. 76 (1996) 3065 |
|
| ωμ+μ- | 830.0 | CLEO II | A. Freyberger et al., Phys. Rev. Lett. 76 (1996) 3065 |
|
| K+K-e+e- | 315.0 | E791 | E.M. Aitala et al., Phys. Rev. Lett. 86 (2001) 3969 |
|
| φe+e- | 59.0 | E791 | E.M. Aitala et al., Phys. Rev. Lett. 86 (2001) 3969 |
| 52.0 | CLEO II | A. Freyberger et al., Phys. Rev. Lett. 76 (1996) 3065 |
|
| K+K-μ+μ- | 33.0 | E791 | E.M. Aitala et al., Phys. Rev. Lett. 86 (2001) 3969 |
|
| φμ+μ- | 410.0 | CLEO II | A. Freyberger et al., Phys. Rev. Lett. 76 (1996) 3065 |
| 31.0 | E791 | E.M. Aitala et al., Phys. Rev. Lett. 86 (2001) 3969 |
|
| K0e+e- | 1700.0 | Mark3 | J. Adler et al., Phys. Rev. D40 (1989) 906 |
| 110.0 | CLEO II | A. Freyberger et al., Phys. Rev. Lett. 76 (1996) 3065 |
|
| K0μ+μ- | 670.0 | CLEO II | A. Freyberger et al., Phys. Rev. Lett. 76 (1996) 3065 |
| 260.0 | E653 | K. Kodama et al., Phys. Lett. B345 (1995) 85 |
|
| K-π+e+e- | 385.0 | E791 | E.M. Aitala et al., Phys. Rev. Lett. 86 (2001) 3969 |
|
| K*0(892)e+e- | 140.0 | CLEO II | A. Freyberger et al., Phys. Rev. Lett. 76 (1996) 3065 |
| 47.0 | E791 | E.M. Aitala et al., Phys. Rev. Lett. 86 (2001) 3969 |
|
| K-π+μ+μ- | 360.0 | E791 | E.M. Aitala et al., Phys. Rev. Lett. 86 (2001) 3969 |
|
| K*0(892)μ+μ- | 1180.0 | CLEO II | A. Freyberger et al., Phys. Rev. Lett. 76 (1996) 3065 |
| 24.0 | E791 | E.M. Aitala et al., Phys. Rev. Lett. 86 (2001) 3969 |
|
| π+π-π0μ+μ- | 810.0 | E653 | K. Kodama et al., Phys. Lett. B345 (1995) 85 |
|
| μ±e∓ | 270.0 | CLEO | P. Haas et al., Phys. Rev. Lett. 60 (1988) 1614 |
| 120.0 | Mark3 | J. Becker et al., Phys. Lett. B193 (1987) 147 |
| 100.0 | Argus | H. Albrecht et al., Phys. Lett. B209 (1988) 380 |
| 19.0 | CLEO II | A. Freyberger et al., Phys. Rev. Lett. 76 (1996) 3065 |
| 17.2 | E789 | D. Pripstein et al., Phys. Rev. D61 (2000) 032005 |
| 8.1 | E791 | E.M. Aitala et al., Phys. Lett. B462 (1999) 401 |
| 0.81 | BaBar | B. Aubert et al., Phys. Rev. Lett. 93 (2004) 191801 |
| 0.26 | Belle | M. Petric et al., Phys. Rev. D81 (2010) 091102R |
| 0.016 | LHCb | R. Aaij et al., Phys.Lett. B754 (2016) 167 |
|
| π0e±μ∓ | 86.0 | CLEO II | A. Freyberger et al., Phys. Rev. Lett. 76 (1996) 3065 |
|
| ηe±μ∓ | 100.0 | CLEO II | A. Freyberger et al., Phys. Rev. Lett. 76 (1996) 3065 |
|
| π+π-e±μ∓ | 15.0 | E791 | E.M. Aitala et al., Phys. Rev. Lett. 86 (2001) 3969 |
|
| ρ0e±μ∓ | 66.0 | E791 | E.M. Aitala et al., Phys. Rev. Lett. 86 (2001) 3969 |
| 49.0 | CLEO II | A. Freyberger et al., Phys. Rev. Lett. 76 (1996) 3065 |
|
| ωe±μ∓ | 120.0 | CLEO II | A. Freyberger et al., Phys. Rev. Lett. 76 (1996) 3065 |
|
| K+K-e±μ∓ | 180.0 | E791 | E.M. Aitala et al., Phys. Rev. Lett. 86 (2001) 3969 |
|
| φe±μ∓ | 47.0 | E791 | E.M. Aitala et al., Phys. Rev. Lett. 86 (2001) 3969 |
| 34.0 | CLEO II | A. Freyberger et al., Phys. Rev. Lett. 76 (1996) 3065 |
|
| K0e±μ∓ | 100.0 | CLEO II | A. Freyberger et al., Phys. Rev. Lett. 76 (1996) 3065 |
|
| K-π+e±μ∓ | 550.0 | E791 | E.M. Aitala et al., Phys. Rev. Lett. 86 (2001) 3969 |
|
| K*0(892)e±μ∓ | 100.0 | CLEO II | A. Freyberger et al., Phys. Rev. Lett. 76 (1996) 3065 |
| 83.0 | E791 | E.M. Aitala et al., Phys. Rev. Lett. 86 (2001) 3969 |
|
| π∓π∓e±e± | 112.0 | E791 | E.M. Aitala et al., Phys. Rev. Lett. 86 (2001) 3969 |
|
| π∓π∓μ±μ± | 29.0 | E791 | E.M. Aitala et al., Phys. Rev. Lett. 86 (2001) 3969 |
|
| K∓π∓e±e± | 206.0 | E791 | E.M. Aitala et al., Phys. Rev. Lett. 86 (2001) 3969 |
|
| K∓π∓μ±μ± | 390.0 | E791 | E.M. Aitala et al., Phys. Rev. Lett. 86 (2001) 3969 |
|
| K∓K∓e±e± | 152.0 | E791 | E.M. Aitala et al., Phys. Rev. Lett. 86 (2001) 3969 |
|
| K∓K∓μ±μ± | 94.0 | E791 | E.M. Aitala et al., Phys. Rev. Lett. 86 (2001) 3969 |
|
| π∓π∓e±μ± | 79.0 | E791 | E.M. Aitala et al., Phys. Rev. Lett. 86 (2001) 3969 |
|
| K∓π∓e±μ± | 218.0 | E791 | E.M. Aitala et al., Phys. Rev. Lett. 86 (2001) 3969 |
|
| K∓K∓e±μ± | 57.0 | E791 | E.M. Aitala et al., Phys. Rev. Lett. 86 (2001) 3969 |
|
| p\,e- | 10.0 | CLEO | P. Rubin et al., Phys. Rev. D79 (2009) 097101 |
|
| pe+ | 11.0 | CLEO | P. Rubin et al., Phys. Rev. D79 (2009) 097101 |