The NIST Reference on Constants, Units and Uncertainty

Fundamental Physical Constants
Constants
Topics:
Values
Energy
Equivalents
Searchable
Bibliography
Background
Constants
Bibliography
Constants,
Units &
Uncertainty
home page
[skip navigation]
proton-neutron mass ratio
 $m_{\rm p}/m_{\rm n}$
 Numerical value  0.998 623 478 12
 Standard uncertainty  0.000 000 000 49
  Relative standard uncertainty  4.9 x 10-10
 Concise form  0.998 623 478 12(49)    
 
Click here for correlation coefficient of this constant with other constants
Source: 2018 CODATA     
recommended values 		 Definition of
uncertainty 		      Correlation coefficient with
any other constant

 
Go to a new search