Proton Spin Puzzle Solved By Supercomputer


  • NEW SPIN ON AN OLD PHYSICS PROBLEM


    Scientists in a research group led by Constantia Alexandrou, professor of physics at the University of Cyprus and the Cyprus Institute, made a crucial step towards solving a three-decades-old puzzle: They have successfully deciphered the total angular momentum (spin) of the nucleon, determining how it's shared among its constituents. CSCS supercomputer Piz Daint provided the necessary computational resources.


    Read more at: https://phys.org/news/2017-10-proton-puzzle.html#jCp


    And


    https://futurism.com/researche…ades-old-physics-mystery/

  • I worry that this might be a little bit of curve fitting together with wishful thinking to make the spin come out to 1/2, especially the sea quark/gluon contribution. (And on inspection I note that the bars for the individual contributions do not cleanly add up to the total, so there's something subtle going on in the graphs.) Has anyone read the paper and gotten a sense of whether this is the case or not?

  • Eric wrote "little bit of curve fitting together with wishful thinking to make the spin come out to 1/2, especially the sea quark/gluon contribution"

    From the ArXiv paper"

    "All results that will be presented in this work are computed on the latest European Twisted Mass Collaboration (ETMC) gauge field ensemble"

    I don't think there is wishful curve fitting but there are ...lots of assumptions...unchallenged. plenty of renormalisation..

    I am sure Cyprus could fit something to Kozima's newer TNCF model if they put their supercomputer on to it.