Inner structure of QED and its gauge invariant angular momenta: A new viewpoint to the final resolution of the nucleon spin crisis

2011 ◽  
Vol 84 (4) ◽  
Author(s):  
Bao-Hua Zhou ◽  
Yong-Chang Huang
2014 ◽  
Vol 29 (09) ◽  
pp. 1430012 ◽  
Author(s):  
Masashi Wakamatsu

Is gauge-invariant complete decomposition of the nucleon spin possible? Although it is a difficult theoretical question which has not reached a complete consensus yet, a general agreement now is that there are at least two physically inequivalent gauge-invariant decompositions (I) and (II) of the nucleon. In these two decompositions, the intrinsic spin parts of quarks and gluons are just common. What discriminate these two decompositions are the orbital angular momentum parts. The orbital angular momenta of quarks and gluons appearing in the decomposition (I) are the so-called "mechanical" orbital angular momenta, while those appearing in the decomposition (II) are the generalized (gauge-invariant) "canonical" ones. By this reason, these decompositions are also called the "mechanical" and "canonical" decompositions of the nucleon spin, respectively. A crucially important question is which decomposition is more favorable from the observational viewpoint. The main objective of this concise review is to try to answer this question with careful consideration of recent intensive researches on this problem.


2012 ◽  
Vol 27 (31) ◽  
pp. 1230032 ◽  
Author(s):  
Y. M. CHO ◽  
MO-LIN GE ◽  
PENGMING ZHANG

We clarify the on-going confusion on the long-standing gauge invariance problem of the nucleon spin decomposition to the spin and angular momentum of quarks and gluons. We provide two gauge-invariant decompositions of nucleon spin which have different physical meanings, using the gauge independent Abelian decomposition. The first one is based on the assumption that all (binding and valence) gluons contribute to the nucleon spin, but the second one is based on the assumption that only the binding gluons (and the quarks) contribute to it.


2014 ◽  
Vol 25 ◽  
pp. 1460031
Author(s):  
MASASHI WAKAMATSU

We argue against the rapidly spreading idea of gauge-invariant-extension (GIE) approach in the nucleon spin decomposition problem, which implies the existence of infinitely many gauge-invariant decomposition of the nucleon spin.


Author(s):  
Emel Altas

Recently, it was shown that the conserved charges of asymptotically anti-de Sitter spacetimes can be written in an explicitly gauge-invariant way in terms of the linearized Riemann tensor and the Killing vectors. Here, we employ this construction to compute the mass and angular momenta of the [Formula: see text]-dimensional Kerr-AdS black holes, which is one of the most remarkable Einstein metrics generalizing the four-dimensional rotating black hole.


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