https://doi.org/10.1140/epja/i2012-12091-8
Letter
On gauge invariant nucleon spin decomposition
1
Institute of Modern Physics, Chinese Academy of Sciences, 730000, Lanzhou, China
2
Research Center for Hadron and CSR Physics, Lanzhou University and Institute of Modern Physics of CAS, 730000, Lanzhou, China
3
Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, 141980, Dubna, Moscow region, Russia
* e-mail: dmipak@gmail.com
Received:
6
March
2012
Revised:
28
May
2012
Accepted:
29
May
2012
Published online:
25
June
2012
A non-uniqueness problem of gauge invariant separation of quark and gluon contributions to nucleon spin is considered. We show that there is a wide number of gauge invariant spin decompositions, and each of them reduces to the canonical one in a special gauge. A class of physical gauge equivalent nucleon spin decompositions is selected by requirements of consistence with helicity notion described within the E(2) little group representation theory and with the gluon helicity Δg measured in the experiment.
© SIF, Springer-Verlag Berlin Heidelberg, 2012
