常用物理常数

1. Physical constants 1. PHYSICAL CONSTANTS Table 1.1. Reviewed 2000 by P.J. Mohr and B.N. Taylor (NIST). Based mainly on the \CODATA Recommended Values of the Fundamental Physical Constants: 1998" by P.J. Mohr and B.N. Taylor, J. Phys. Chem. Ref. Data 28, 1713 (1999) and Rev. Mod. Phys. 72, 351 (2000). The last group of constants (beginning with the Fermi coupling constant) comes from the Particle Data Group. The �gures in parentheses after the values give the 1-standard-deviation uncertainties in the last digits; the corresponding uncertainties in parts per billion (ppb) are given in the last column. This set of constants (aside from the last group) is recommended for international use by CODATA (the Committee on Data for Science and Technology). The full 1998 CODATA set of constants may be found at http://physics.nist.gov/constants Quantity Symbol, equation Value Uncertainty (ppb) speed of light in vacuum c 299 792 458 m s−1 exact� Planck constant h 6.626 068 76(52)�10−34 J s 78 Planck constant, reduced ~ � h=2� 1.054 571 596(82)�10−34 J s 78 = 6.582 118 89(26)�10−22 MeV s 39 electron charge magnitude e 1.602 176 462(63)�10−19 C = 4.803 204 20(19)�10−10 esu 39, 39 conversion constant ~c 197.326 960 2(77) MeV fm 39 conversion constant (~c)2 0.389 379 292(30) GeV2 mbarn 78 electron mass me 0.510 998 902(21) MeV=c2 = 9.109 381 88(72)�10−31 kg 40, 79 proton mass mp 938.271 998(38) MeV=c2 = 1.672 621 58(13)�10−27 kg 40, 79 = 1.007 276 466 88(13) u = 1836.152 667 5(39) me 0.13, 2.1 deuteron mass md 1875.612 762(75) MeV=c2 40 uni�ed atomic mass unit (u) (mass 12C atom)/12 = (1 g)/(NA mol) 931.494 013(37) MeV=c2 = 1.660 538 73(13)�10−27 kg 40, 79 permittivity of free space �0 = 1=�0c2 8.854 187 817 : : : �10−12 F m−1 exact permeability of free space �0 4� � 10−7 N A−2 = 12.566 370 614 : : : �10−7 N A−2 exact �ne-structure constant � = e2/4��0~c 7.297 352 533(27)�10−3 = 1=137:035 999 76(50)y 3.7,3.7 classical electron radius re = e2=4��0mec2 2.817 940 285(31)�10−15 m 11 (e− Compton wavelength)/2� −�e = ~=mec = re�−1 3.861 592 642(28)�10−13 m 7.3 Bohr radius (mnucleus =1) a1 = 4��0~2=mee2 = re�−2 0.529 177 208 3(19)�10−10 m 3.7 wavelength of 1 eV/c particle hc=e 1.239 841 857(49)�10−6 m 39 Rydberg energy hcR1 = mee4=2(4��0)2~2 = mec2�2=2 13.605 691 72(53) eV 39 Thomson cross section �T = 8�r2e/3 0.665 245 854(15) barn 22 Bohr magneton �B = e~=2me 5.788 381 749(43)�10−11 MeV T−1 7.3 nuclear magneton �N = e~=2mp 3.152 451 238(24)�10−14 MeV T−1 7.6 electron cyclotron freq./�eld !ecycl=B = e=me 1.758 820 174(71)�1011 rad s−1 T−1 40 proton cyclotron freq./�eld !pcycl=B = e=mp 9.578 834 08(38)�107 rad s−1 T−1 40 gravitational constantz GN 6.673(10)�10−11 m3 kg−1 s−2 1:5� 106 = 6.707(10)�10−39 ~c (GeV=c2)−2 1:5� 106 standard grav. accel., sea level gn 9.806 65 m s−2 exact Avogadro constant NA 6.022 141 99(47)�1023 mol−1 79 Boltzmann constant k 1.380 650 3(24)�10−23 J K−1 1700 = 8.617 342(15)�10−5 eV K−1 1700 molar volume, ideal gas at STP NAk(273.15 K)/(101 325 Pa) 22.413 996(39)�10−3 m3 mol−1 1700 Wien displacement law constant b = �maxT 2.897 768 6(51)�10−3 m K 1700 Stefan-Boltzmann constant � = �2k4=60~3c2 5.670 400(40)�10−8 W m−2 K−4 7000 Fermi coupling constant�� GF =(~c)3 1.166 39(1)�10−5 GeV−2 9000 weak-mixing angle sin2 b�(MZ) (MS) 0.23117(16)yy 7� 105 W� boson mass mW 80.419(56) GeV=c2 7� 105 Z0 boson mass mZ 91.1882(22) GeV=c2 2:4� 104 strong coupling constant �s(mZ) 0.1185(20) 1:7� 107 � = 3.141 592 653 589 793 238 e = 2.718 281 828 459 045 235 γ = 0.577 215 664 901 532 861 1 in � 0:0254 m 1 �A � 0:1 nm 1 barn � 10−28 m2 1 G � 10−4 T 1 dyne � 10−5 N 1 erg � 10−7 J 1 eV = 1:602 176 462(63)� 10−19 J 1 eV/c2 = 1:782 661 731(70)� 10−36 kg 2:997 924 58� 109 esu = 1 C kT at 300 K = [38:681 686(67)]−1 eV 0 �C � 273:15 K 1 atmosphere � 760 Torr � 101 325 Pa � The meter is the length of the path traveled by light in vacuum during a time interval of 1/299 792 458 of a second. y At Q2 = 0. At Q2 � m2W the value is approximately 1/128.z Absolute lab measurements of GN have been made only on scales of 1 mm to 1 m.�� See the discussion in Sec. 10, \Electroweak model and constraints on new physics." yy The corresponding sin2 � for the e�ective angle is 0.23147(16).