Beschreibung:
<jats:p>We review strategies to unveil the primordial
large-<jats:inline-formula><jats:alternatives><jats:tex-math>x</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>x</mml:mi></mml:math></jats:alternatives></jats:inline-formula>
structure of the nucleons as well as the pion from hard-scattering
experiments. Ideas are presented for learning about the
<jats:inline-formula><jats:alternatives><jats:tex-math>x\to 1</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>x</mml:mi><mml:mo>→</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:math></jats:alternatives></jats:inline-formula>
limit of nonperturbative QCD dynamics at energy scales of order 1 GeV
from collider experiments at much higher scales. The behavior of parton
distributions at <jats:inline-formula><jats:alternatives><jats:tex-math>x\to 1</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>x</mml:mi><mml:mo>→</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:math></jats:alternatives></jats:inline-formula>
predicted by the quark counting rules and other low-energy theoretical
approaches is contrasted with phenomenological PDFs. Polynomial mimicry
of PDF parametrizations is one of many factors that influence the
apparent power of the <jats:inline-formula><jats:alternatives><jats:tex-math>(1-x)</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mo stretchy="false" form="prefix">(</mml:mo><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi><mml:mo stretchy="false" form="postfix">)</mml:mo></mml:mrow></mml:math></jats:alternatives></jats:inline-formula>
falloff. We discuss implications of the mimicry for the
large-<jats:inline-formula><jats:alternatives><jats:tex-math>x</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>x</mml:mi></mml:math></jats:alternatives></jats:inline-formula>
falloff of the pion PDFs.</jats:p>