@article{10272/21167,
year = {2022},
month = {1},
url = {http://hdl.handle.net/10272/21167},
abstract = {Analyses of the pion valence-quark distribution
function (DF), uπ (x; ζ ), which explicitly incorporate the
behaviour of the pion wave function prescribed by quantum chromodynamics (QCD), predict uπ (x  1; ζ ) ∼
(1 − x)β(ζ ), β(ζ  m p) > 2, where m p is the proton mass.
Nevertheless, more than forty years after the first experiment
to collect data suitable for extracting the x  1 behaviour
of uπ , the empirical status remains uncertain because some
methods used to fit existing data return a result for uπ that
violates this constraint. Such disagreement entails one of the
following conclusions: the analysis concerned is incomplete;
not all data being considered are a true expression of qualities
intrinsic to the pion; or QCD, as it is currently understood,
is not the theory of strong interactions. New, precise data are
necessary before a final conclusion is possible. In developing these positions, we exploit a single proposition, viz. there
is an effective charge which defines an evolution scheme
for parton DFs that is all-orders exact. This proposition has
numerous corollaries, which can be used to test the character
of any DF, whether fitted or calculated},
organization = {We are grateful for constructive comments from
K.-L. Cai, O. Denisov, F. de Soto, T. Frederico, J. Friedrich, C. Mezrag,
V. Mokeev, W.-D. Nowak, C. Quintans, G. Salmè and J. Segovia. Work
supported by: National Natural Science Foundation of China (Grant
nos. 12135007, 11805097); Helmholtz-Zentrum Dresden-Rossendorf
High Potential Programme; Spanish Ministry of Science and Innovation (MICINN) (Grant nos. PID2020-113334GB, PID2019-107844GBC22); Generalitat Valenciana (Grant no. Prometeo/2019/087); Junta
de Andalucía (Grant nos. P18-FR-5057, UHU-1264517, UHU EPIT2021); and STRONG-2020 “The strong interaction at the frontier of
knowledge: fundamental research and applications” which received
funding from the European Union’s Horizon 2020 research and innovation programme (grant no. 824093},
publisher = {Springer},
title = {Concerning pion parton distributions},
doi = {10.1140/epja/s10050-021-00658-7},
author = {Cui, Zhu-Fang and Ding, M. and Morgado Chávez, José Manuel and Raya, Khépani and Binosi, Daniele and Chang, L. and Papavassiliou, J. and Roberts, Craig D. and Rodríguez Quintero, José and Schmidt, S. M.},
}