

A082726


Continued fraction expansion of current estimate of the finestructure constant alpha.


2




OFFSET

0,2


COMMENTS

The estimate is continually changing.
The term a(7) is today known to be in between 15 and 17, but most likely equal to 16.
The value refers to the zeroenergy limit of the coupling constant. At higher energies the value increases; e.g. at the energy 90 GeV of the Zboson, it is about 1/128.
a(7) is believed to be 17 or 18 according to the revised 2014 CODATA value.  Charles R Greathouse IV, Sep 13 2017


LINKS

Table of n, a(n) for n=0..6.
NIST, finestructure constant
NIST, inverse finestructure constant
Wikipedia, Finestructure constant.


FORMULA

alpha = e^2*c*mu/2h, where e ~ 1.602e19 is the elementary charge, c = 299792458 m/s the speed of light, mu = pi*4e7 H/m the vacuum permeability, and h ~ 6.626e34 Planck's constant.


EXAMPLE

CODATA 2014: alpha = 0.007 297 352 5664(17) = 1 / 137.035 999 139(31), where values in parentheses indicate uncertainty in the preceding 2 digits.


CROSSREFS

Cf. A005600.
Sequence in context: A091510 A134885 A259680 * A189998 A138358 A138329
Adjacent sequences: A082723 A082724 A082725 * A082727 A082728 A082729


KEYWORD

nonn,cofr,hard,more


AUTHOR

N. J. A. Sloane, May 21 2003


STATUS

approved



