Fundamental Physical Constants — Extensive Listing
Relative std.
Quantity Symbol Value Unit uncert.urh/me 7 .273 895 0972(33)× 10 −^4 m^2 s−^14. 5 × 10 −^10
Electroweak
Fermi coupling constant^3 GF/( ̄hc)^31 .166 3787(6)× 10 −^5 GeV−^25. 1 × 10 −^7
weak mixing angle^4 θW(on-shell scheme)
sin^2 θW=s^2 W≡ 1 −(mW/mZ)^2 sin^2 θW 0 .2223(21) 9. 5 × 10 −^3
Electron, e−
electron mass me 9 .109 383 56(11)× 10 −^31 kg 1. 2 × 10 −^8
5 .485 799 090 70(16)× 10 −^4 u 2. 9 × 10 −^11
energy equivalent mec^28 .187 105 65(10)× 10 −^14 J 1. 2 × 10 −^8
0 .510 998 9461(31) MeV 6. 2 × 10 −^9
electron-muon mass ratio me/mμ 4 .836 331 70(11)× 10 −^32. 2 × 10 −^8
electron-tau mass ratio me/mτ 2 .875 92(26)× 10 −^49. 0 × 10 −^5
electron-proton mass ratio me/mp 5 .446 170 213 52(52)× 10 −^49. 5 × 10 −^11
electron-neutron mass ratio me/mn 5 .438 673 4428(27)× 10 −^44. 9 × 10 −^10
electron-deuteron mass ratio me/md 2 .724 437 107 484(96)× 10 −^43. 5 × 10 −^11
electron-triton mass ratio me/mt 1 .819 200 062 203(84)× 10 −^44. 6 × 10 −^11
electron-helion mass ratio me/mh 1 .819 543 074 854(88)× 10 −^44. 9 × 10 −^11
electron to alpha particle mass ratio me/mα 1 .370 933 554 798(45)× 10 −^43. 3 × 10 −^11
electron charge to mass quotient −e/me − 1 .758 820 024(11)× 1011 Ckg−^16. 2 × 10 −^9
electron molar massNAme M(e),Me 5 .485 799 090 70(16)× 10 −^7 kg mol−^12. 9 × 10 −^11
Compton wavelengthh/mecλC 2 .426 310 2367(11)× 10 −^12 m 4. 5 × 10 −^10
λC/ 2 π=αa 0 =α^2 / 4 πR∞ λC 386 .159 267 64(18)× 10 −^15 m 4. 5 × 10 −^10
classical electron radiusα^2 a 0 re 2 .817 940 3227(19)× 10 −^15 m 6. 8 × 10 −^10
Thomson cross section (8π/3)re^2 σe 0 .665 245 871 58(91)× 10 −^28 m^21. 4 × 10 −^9
electron magnetic moment μe − 928 .476 4620(57)× 10 −^26 JT−^16. 2 × 10 −^9
to Bohr magneton ratio μe/μB − 1 .001 159 652 180 91(26) 2. 6 × 10 −^13
to nuclear magneton ratio μe/μN − 1838 .281 972 34(17) 9. 5 × 10 −^11
electron magnetic moment
anomaly|μe|/μB− 1 ae 1 .159 652 180 91(26)× 10 −^32. 3 × 10 −^10
electrong-factor−2(1 +ae) ge − 2 .002 319 304 361 82(52) 2. 6 × 10 −^13
electron-muon magnetic moment ratio μe/μμ 206 .766 9880(46) 2. 2 × 10 −^8
electron-proton magnetic moment ratio μe/μp − 658 .210 6866(20) 3. 0 × 10 −^9
electron to shielded proton magnetic
moment ratio (H 2 O, sphere, 25◦C) μe/μ′p − 658 .227 5971(72) 1. 1 × 10 −^8
electron-neutron magnetic moment ratio μe/μn 960 .920 50(23) 2. 4 × 10 −^7
electron-deuteron magnetic moment ratio μe/μd − 2143 .923 499(12) 5. 5 × 10 −^9
electron to shielded helion magnetic
moment ratio (gas, sphere, 25◦C) μe/μ′h 864 .058 257(10) 1. 2 × 10 −^8
electron gyromagnetic ratio 2 |μe|/ ̄hγe 1 .760 859 644(11)× 1011 s−^1 T−^16. 2 × 10 −^9
γe/ 2 π 28 024.951 64(17) MHz T−^16. 2 × 10 −^9
Muon,μ−
muon mass mμ 1 .883 531 594(48)× 10 −^28 kg 2. 5 × 10 −^8
0 .113 428 9257(25) u 2. 2 × 10 −^8
energy equivalent mμc^21 .692 833 774(43)× 10 −^11 J 2. 5 × 10 −^8
105 .658 3745(24) MeV 2. 3 × 10 −^8
muon-electron mass ratio mμ/me 206 .768 2826(46) 2. 2 × 10 −^8
muon-tau mass ratio mμ/mτ 5 .946 49(54)× 10 −^29. 0 × 10 −^5
muon-proton mass ratio mμ/mp 0 .112 609 5262(25) 2. 2 × 10 −^8