Issue |
EPJ Web Conf.
Volume 164, 2017
5th International Conference on New Frontiers in Physics
|
|
---|---|---|
Article Number | 01007 | |
Number of page(s) | 7 | |
Section | Plenary | |
DOI | https://doi.org/10.1051/epjconf/201716401007 | |
Published online | 05 December 2017 |
https://doi.org/10.1051/epjconf/201716401007
COMPASS results on proton longitudinal spin structure function g1 and quark fragmentation functions
IRFU, CEA Saclay, Université Paris-Saclay, France
Published online: 5 December 2017
We present a few recent highlights from the COMPASS experiment at CERN, related to the nucleon spin and structure: the proton spin structure function g1 p(x) measured using 200 GeV polarized muons, together with a QCD fit of g1 world data; pion and kaon multiplicities in DIS in view of constraining quark fragmentation functions.
The statistical precision on g1p is improved by a factor of ~2 at low x. A reevaluation of the Bjorken sum rule based on COMPASS data alone confirms its validation within 9% accuracy. An NLO QCD fit to g1 world data leads to a value of the quark spin contribution to the nucleon spin ΔΣ, between 0.26 and 0.36 at Q2= 3 (GeV/c)2, the size of the uncertainty being driven by the unknown shape of the polarized parton distributions.
The results on pion and kaon multiplicities produced in DIS of muons off an isoscalar target constitute an impressive data set of more than 400 points in π and 400 in K, covering a large kinematical domain in (x, z, Q2), which will be used in future NLO QCD fits to extract quark fragmentation functions into π and K. A LO fit is performed to extract the favoured and unfavoured quark fragmentation functions into pions.
© The Authors, published by EDP Sciences, 2017
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (http://creativecommons.org/licenses/by/4.0/).
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.