From: physics. nist. gov/constants Fundamental Physical Constants-Complete Listing Relative std Quantity Symbol Value Unit uncert. Il tau-electron mass ratio n/me3477.60(57) 16×10-4 tau-muon mass ratio i/ 168188(27) 1.6×10 tau-proton mass ratio m/mp1.89396(31) 1.6×10 tau-neutron mass ratio m/mn189135(31) 1.6×10 tau molar mass NAm M(),M11.90774(31)×10-3 kg mol-11.6×10- tau Compton wavelength h/mc ic 069770(11)×10-15 1.6×10-4 0.l11042(18)×10 15 Proton, p proton mass 1.67262158(13)×10-27kg 79×10-8 Ar (p)u(pr relative atomic mass times u) 1.00727646688(13) 1.3×10-10 nergy equivalent mDC 1.50327731(12)×10-10J .9 in mev 938.271998(38) Mev 4.0×10-8 proton-electron mass ratio m1p/me1836.1526675(39) 2.1×10-9 proton-muon mass ratio mp/m8.88024408(27) 30×10-8 proton-tau mass ratio mp/m:0.527994(86) 16×10-4 proton-neutron mass ratio mp/mn0.99862347855(58) 58×10=10 proton charge to mass quotient 957883408(38)×107 C kg 4.0×10-8 proton molar mass NAmp M(p),M1.00727646688(13)×10-3 kg mol-11.3×10-10 proton Compton wavelength h/mpc A 1.321409847(10)×10-15m 7.6×10-9 0.2103089089(16)×10~15m 7.6×10-9 proton magnetic moment 1410606633(58×10-26JT-14.1×10-8 to bohr magneton ratio p/B1.521032203(15)×10-3 1.0×10-8 to nuclear magneton ratio 2.792847337029) 10×10-8 proton g-factor 2up/uN 5.585694675(57) 10×10-8 Toton-neutron magnetic moment ratio 1.45989805(34) 2.4×10-7 shielded proton magnetic moment 1.410570399(59)×10-26JT-1 4.2×10-8 (H2O, sphere, 25C to bohr magneton ratio p/μB 1.520993132(16)×10-3 1.1 to nuclear magneton rati Hm/N2.792775597(31) 1.1×10=8 proton magnetic shielding correction I-un/u 25687(15)×10-6 5.7×10-4 (H2O, sphere,25°C) proton gyromagnetic ratio 2pp/h 26752222(11)×108 4.l×10-8 /2r 42.5774825(18) MHzT-14.1×10 shielded proton gyromagnetic ratio 2un/h Yp 267515341(11)×108 S-I T 4.2×10-8 (H2O, sphere,25°C) y/2x425763888(18) MHzT-14.2×10-8 Journal of Physical and Chemical Reference Data, Vol. 28, No. 6, 1999 and Reviews of Modern Physics, Vol. 72, No. 2, 2000From: physics.nist.gov/constants Fundamental Physical Constants — Complete Listing Relative std. Quantity Symbol Value Unit uncert. ur tau-electron mass ratio mτ/me 3 477.60(57) 1.6 × 10−4 tau-muon mass ratio mτ/mµ 16.8188(27) 1.6 × 10−4 tau-proton mass ratio mτ/mp 1.893 96(31) 1.6 × 10−4 tau-neutron mass ratio mτ/mn 1.891 35(31) 1.6 × 10−4 tau molar mass NAmτ M(τ), Mτ 1.907 74(31) × 10−3 kg mol−1 1.6 × 10−4 tau Compton wavelength h/mτc λC,τ 0.697 70(11) × 10−15 m 1.6 × 10−4 λC,τ/2π žC,τ 0.111 042(18) × 10−15 m 1.6 × 10−4 Proton, p proton mass mp 1.672 621 58(13) × 10−27 kg 7.9 × 10−8 in u, mp = Ar(p) u (proton relative atomic mass times u) 1.007 276 466 88(13) u 1.3 × 10−10 energy equivalent mpc2 1.503 277 31(12)× 10−10 J 7.9 × 10−8 in MeV 938.271 998(38) MeV 4.0 × 10−8 proton-electron mass ratio mp/me 1 836.152 6675(39) 2.1 × 10−9 proton-muon mass ratio mp/mµ 8.880 244 08(27) 3.0 × 10−8 proton-tau mass ratio mp/mτ 0.527 994(86) 1.6 × 10−4 proton-neutron mass ratio mp/mn 0.998 623 478 55(58) 5.8 × 10−10 proton charge to mass quotient e/mp 9.578 834 08(38) × 107 C kg−1 4.0 × 10−8 proton molar mass NAmp M(p), Mp 1.007 276 466 88(13)× 10−3 kg mol−1 1.3 × 10−10 proton Compton wavelength h/mpc λC,p 1.321 409 847(10)× 10−15 m 7.6 × 10−9 λC,p/2π žC,p 0.210 308 9089(16) × 10−15 m 7.6 × 10−9 proton magnetic moment µp 1.410 606 633(58) × 10−26 J T−1 4.1 × 10−8 to Bohr magneton ratio µp/µB 1.521 032 203(15) × 10−3 1.0 × 10−8 to nuclear magneton ratio µp/µN 2.792 847 337(29) 1.0 × 10−8 proton g-factor 2µp/µN gp 5.585 694 675(57) 1.0 × 10−8 proton-neutron magnetic moment ratio µp/µn −1.459 898 05(34) 2.4 × 10−7 shielded proton magnetic moment µ0 p 1.410 570 399(59) × 10−26 J T−1 4.2 × 10−8 (H2O, sphere, 25 ◦C) to Bohr magneton ratio µ0 p/µB 1.520 993 132(16) × 10−3 1.1 × 10−8 to nuclear magneton ratio µ0 p/µN 2.792 775 597(31) 1.1 × 10−8 proton magnetic shielding correction 1 − µ0 p/µp σ0 p 25.687(15) × 10−6 5.7 × 10−4 (H2O, sphere, 25 ◦C) proton gyromagnetic ratio 2µp/ γp 2.675 222 12(11) × 108 s−1 T−1 4.1 × 10−8 γp/2π 42.577 4825(18) MHz T−1 4.1 × 10−8 shielded proton gyromagnetic ratio 2µ0 p/ γ 0 p 2.675 153 41(11)× 108 s−1 T−1 4.2 × 10−8 (H2O, sphere, 25 ◦C) γ 0 p/2π 42.576 3888(18) MHz T−1 4.2 × 10−8 Neutron, n Page 4 Source: Peter J. Mohr and Barry N. Taylor, CODATA Recommended Values of the Fundamental Physical Constants: 1998, Journal of Physical and Chemical Reference Data, Vol. 28, No. 6, 1999 and Reviews of Modern Physics, Vol. 72, No. 2, 2000