<p>We investigate the contribution of the charm-anticharm (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>c</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover></math>) asymmetry of the proton eigenstate obtained from QCD lattice gauge to the asymmetry of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>D</mi><mo>+</mo></msup><mo>,</mo><msup><mi>D</mi><mo>−</mo></msup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>D</mi><mn>0</mn></msup><mo>,</mo><msup><mover accent="true"><mi>D</mi><mo stretchy="false">¯</mo></mover><mn>0</mn></msup></math> mesons produced in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><mi>p</mi></math> collisions at large Feynman variables <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>x</mi></math>. It is shown that an important tool for establishing the intrinsic charm (IC) content of the proton is the charm hadron-antihadron asymmetry formed in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><mi>p</mi></math> collisions. Predictions for the asymmetry as a function of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>x</mi></math> for different IC probabilities are presented. We show that the interference of the intrinsic <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mo stretchy="false">|</mo><mi>u</mi><mi>u</mi><mi>d</mi><mi>c</mi><mover accent="true"><mrow><mi>c</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover><mo stretchy="false">⟩</mo></mrow></math> Fock state with the standard contribution from the perturbative QCD evolution leads to a large <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>D</mi><mo>+</mo></msup><msup><mi>D</mi><mo>−</mo></msup></math> asymmetry at large Feynman <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>x</mi></math>.</p>

JINR

G.I. Lykasov

M.N. Sorokovikov

United States

S.J. Brodsky

Intrinsic charm and the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>D</mi><mo>+</mo></msup><mo>−</mo><msup><mi>D</mi><mo>−</mo></msup></math> asymmetry produced in proton-proton collisions

In this work, a new set of parton distribution functions taking into account the intrinsic charm (IC) contribution is presented. We focus on the impact of the European Muon Collaboration (EMC) measurements on the large <math><mi>x</mi></math> charm structure function as the strongest evidence for the intrinsic charm when combined with the HERA, SLAC, and BCDMS data. The main goal of this paper is the simultaneous determination of the intrinsic charm probability <math><mrow><msub><mrow><mi>P</mi></mrow><mrow><mi>c</mi><mrow><mover><mrow><mi>c</mi></mrow><mrow><mo>¯</mo></mrow></mover><mo>/</mo><mi>p</mi></mrow></mrow></msub></mrow></math> and strong coupling <math><msub><mi>α</mi><mi>s</mi></msub></math>. This allows us to study the interaction of these two quantities as well as the influence on the PDFs in the presence of IC contributions. By considering <math><msub><mi>α</mi><mi>s</mi></msub></math> which can be fix or free parameter from our QCD analysis, we find that although there is not a significant change in the extracted central value of PDFs and their uncertainties, the obtained value of <math><msub><mi>P</mi><mrow><mi>c</mi><mrow><mover><mi>c</mi><mo>¯</mo></mover><mo>/</mo><mi>p</mi></mrow></mrow></msub></math> change by factor 7.8%. The extracted value of <math><msub><mi>P</mi><mrow><mi>c</mi><mrow><mover><mi>c</mi><mo>¯</mo></mover><mo>/</mo><mi>p</mi></mrow></mrow></msub></math> in the present QCD analysis is consistent with the recent reported upper limit of 1.93%, which is obtained for the first time from LHC measurements. We show the intrinsic charm probability is sensitive to the strong coupling constant and also the charm mass. The extracted value of the strong coupling constant <math><mrow><msub><mrow><mi>α</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>(</mo><msubsup><mrow><mi>M</mi></mrow><mrow><mi>Z</mi></mrow><mrow><mn>2</mn></mrow></msubsup><mo>)</mo><mo>=</mo><mn>0.1191</mn><mo>±</mo><mn>0.0008</mn></mrow></math> at NLO is in good agreement with the world average value and available theoretical models.

Iran

H. Abdolmaleki

A. Khorramian

Parton distribution functions and constraints on the intrinsic charm content of the proton using the Brodsky-Hoyer-Peterson-Saka approach

Establishing an explicit connection between the long distance physics of confinement and the dynamical interactions of quarks and gluons at short distances has been a long-sought goal of quantum chromodynamics. Using holographic QCD, we derive a direct analytic relation between the scale Îº which determines the masses of hadrons and the scale Îs which controls the predictions of perturbative QCD at very short distances. The resulting prediction Îs=0.341Â±0.032Â GeV in the MSâ¾ scheme agrees well with the experimental average 0.339Â±0.016Â GeV . We also derive a relation between Îs and the QCD string tension Ï . This connection between the fundamental hadronic scale underlying the physics of quark confinement and the perturbative QCD scale controlling hard collisions can be carried out in any renormalization scheme.

A. Deur

Costa Rica

G.F. de Teramond

Connecting the hadron mass scale to the fundamental mass scale of quantum chromodynamics

We present a review of the state of the art of our understanding of the intrinsic charm and bottom content of the nucleon. We discuss theoretical calculations, constraints from global analyses, and collider observables sensitive to the intrinsic heavy quark distributions. A particular emphasis is put on the potential of a high energy and high luminosity fixed target experiment using the LHC beams (AFTER@LHC) to search for intrinsic charm.