| Decay Mode | Experiment | Reference | Upper Limit @ 90% C.L. | Luminosity |
| (10-8) | (fb-1 @ ϒ(4S)) (unless otherwise mentioned) | |||
| τ- → e- γ | Belle | Phys.Lett.B666:16,2008 | 12 | 535 |
| BaBar | Phys.Rev.Lett.104:021802,2010 | 3.3 | 470 @ ϒ(4S), 31 @ ϒ(3S), 15 @ ϒ(2S) | |
| τ- → μ- γ | Belle | Phys.Lett.B666:16,2008 | 4.5 | 535 |
| BaBar | Phys.Rev.Lett.104:021802,2010 | 4.4 | 470 @ ϒ(4S), 31 @ ϒ(3S), 15 @ ϒ(2S) |
♦ τ- → l- + P0 (where P0 = π0, η, η’, Ks)
| Decay Mode | Experiment | Reference | Upper Limit @ 90% C.L. | Luminosity |
| (10-8) | (fb-1 @ ϒ(4S)) (unless otherwise mentioned) | |||
| τ- → e- π0 | Belle | Blois 2010 | 2.2 | 802 @ ϒ(4S), 99 @ ϒ(5S) |
| BaBar | Phys.Rev.Lett.98:061803,2008 | 13 | 339 | |
| τ- → μ- π0 | Belle | Blois 2010 | 2.7 | 802 @ ϒ(4S), 99 @ ϒ(5S) |
| BaBar | Phys.Rev.Lett.98:061803,2008 | 11 | 339 | |
| τ- → e- η | Belle | Blois 2010 | 4.4 | 802 @ ϒ(4S), 99 @ ϒ(5S) |
| BaBar | Phys.Rev.Lett.98:061803,2008 | 16 | 339 | |
| τ- → μ- η | Belle | Blois 2010 | 2.3 | 802 @ ϒ(4S), 99 @ ϒ(5S) |
| BaBar | Phys.Rev.Lett.98:061803,2008 | 15 | 339 | |
| τ- → e- η’ | Belle | Blois 2010 | 3.6 | 802 @ ϒ(4S), 99 @ ϒ(5S) |
| BaBar | Phys.Rev.Lett.98:061803,2008 | 24 | 339 | |
| τ- → μ- η’ | Belle | Blois 2010 | 3.8 | 802 @ ϒ(4S), 99 @ ϒ(5S) |
| BaBar | Phys.Rev.Lett.98:061803,2008 | 14 | 339 | |
| τ- → e- Ks | Belle | Phys.Lett.B692:4-9,2010 | 2.6 | 671 |
| BaBar | Phys.Rev.D79:012004,2009 | 3.3 | 469 | |
| τ- → μ- Ks | Belle | Phys.Lett.B692:4-9,2010 | 2.3 | 671 |
| BaBar | Phys.Rev.D79:012004,2009 | 4.0 | 469 |
♦ τ- → l- + S ( where S is a scalar meson)
| Decay Mode | Experiment | Reference | Upper Limit @ 90% C.L. | Luminosity |
| (10-8) | (fb-1 @ ϒ(4S)) | |||
| τ- → e- f0(980) | Belle | Phys.Lett.B672:317,2009 | 3.2 (incl. Br(f0→π+π-)) | 671 |
| τ- → μ- f0(980) | Belle | Phys.Lett.B672:317,2009 | 3.4 (incl. Br(f0→π+π-)) | 671 |
♦ τ- → l- + V0 (where V0 is a vector boson)
| Decay Mode | Experiment | Reference | Upper Limit @ 90% C.L. | Luminosity |
| (10-8) | (fb-1 @ ϒ(4S)) (unless otherwise mentioned) | |||
| τ- → e- ρ0 | Belle | Phys.Lett.B699:251-257,2011 | 1.8 | 782 @ ϒ(4S), 72 @ ϒ(5S) |
| BaBar | Phys.Rev.Lett.103:021801,2009 | 4.6 | 451 | |
| τ- → μ- ρ0 | Belle | Phys.Lett.B699:251-257,2011 | 1.2 | 782 @ ϒ(4S), 72 @ ϒ(5S) |
| BaBar | Phys.Rev.Lett.103:021801,2009 | 2.6 | 451 | |
| τ- → e- K* | Belle | Phys.Lett.B699:251-257,2011 | 3.2 | 782 @ ϒ(4S), 72 @ ϒ(5S) |
| BaBar | Phys.Rev.Lett.103:021801,2009 | 5.9 | 451 | |
| τ- → μ- K* | Belle | Phys.Lett.B699:251-257,2011 | 7.2 | 782 @ ϒ(4S), 72 @ ϒ(5S) |
| BaBar | Phys.Rev.Lett.103:021801,2009 | 17 | 451 | |
| τ- → e- K* | Belle | Phys.Lett.B699:251-257,2011 | 3.4 | 782 @ ϒ(4S), 72 @ ϒ(5S) |
| BaBar | Phys.Rev.Lett.103:021801,2009 | 4.6 | 451 | |
| τ- → μ- K* | Belle | Phys.Lett.B699:251-257,2011 | 7.0 | 782 @ ϒ(4S), 72 @ ϒ(5S) |
| BaBar | Phys.Rev.Lett.103:021801,2009 | 7.3 | 451 | |
| τ- → e- φ | Belle | Phys.Lett.B699:251-257,2011 | 3.1 | 782 @ ϒ(4S), 72 @ ϒ(5S) |
| BaBar | Phys.Rev.Lett.103:021801,2009 | 3.1 | 451 | |
| τ- → μ- φ | Belle | Phys.Lett.B699:251-257,2011 | 8.4 | 782 @ ϒ(4S), 72 @ ϒ(5S) |
| BaBar | Phys.Rev.Lett.103:021801,2009 | 19 | 451 | |
| τ- → e- ω | Belle | Phys.Lett.B699:251-257,2011 | 4.8 | 782 @ ϒ(4S), 72 @ ϒ(5S) |
| BaBar | Phys.Rev.Lett.100:071802,2008 | 11 | 384 | |
| τ- → μ- ω | Belle | Phys.Lett.B699:251-257,2011 | 4.7 | 782 @ ϒ(4S), 72 @ ϒ(5S) |
| BaBar | Phys.Rev.Lett.100:071802,2008 | 10 | 384 |
♦ τ- → l- l+ l-
| Decay Mode | Experiment | Reference | Upper Limit @ 90% C.L. | Luminosity |
| (10-8) | (fb-1 @ ϒ(4S)) | |||
| τ- → e- e+ e- | Belle | Phys.Lett.B687:139-143,2010 | 2.7 | 782 |
| BaBar | Phys.Rev.D81:111101(R),2010 | 2.9 | 468 | |
| τ- → μ- e+ e- | Belle | Phys.Lett.B687:139-143,2010 | 1.8 | 782 |
| BaBar | Phys.Rev.D81:111101(R),2010 | 2.2 | 468 | |
| τ- → e- μ+ μ- | Belle | Phys.Lett.B687:139-143,2010 | 2.7 | 782 |
| BaBar | Phys.Rev.D81:111101(R),2010 | 3.2 | 468 | |
| τ- → μ- μ+ μ- | Belle | Phys.Lett.B687:139-143,2010 | 2.1 | 782 |
| BaBar | Phys.Rev.D81:111101(R),2010 | 3.3 | 468 | |
| τ- → e- μ+ e- | Belle | Phys.Lett.B687:139-143,2010 | 1.5 | 782 |
| BaBar | Phys.Rev.D81:111101(R),2010 | 1.8 | 468 | |
| τ- → μ- e+ μ- | Belle | Phys.Lett.B687:139-143,2010 | 1.7 | 782 |
| BaBar | Phys.Rev.D81:111101(R),2010 | 2.6 | 468 |
♦ τ- → l- h+ h'-, l- h0 h0, h- l+ h'-
♦ τ- → Λ + h- (where h = π, K)
| Decay Mode | Experiment | Reference | Upper Limit @ 90% C.L. | Luminosity |
| (10-8) | (fb-1 @ ϒ(4S)) | |||
| τ- → Λ π- | Belle | Phys.Lett.B632:51,2006 | 7.2 | 154 |
| Babar | Nucl.Phys.Proc.Suppl.169:186-191,2007 | 5.8 | 237 | |
| τ- → Λ π- | Belle | Phys.Lett.B632:51,2006 | 14 | 154 |
| Babar | Nucl.Phys.Proc.Suppl.169:186-191,2007 | 5.9 | 237 | |
| τ- → Λ K- | Babar | Nucl.Phys.Proc.Suppl.169:186-191,2007 | 15 | 237 |
| τ- → Λ K- | Babar | Nucl.Phys.Proc.Suppl.169:186-191,2007 | 7.2 | 237 |