From Quarks to Hadrons: Deep-Inelastic Scattering and Parton Model

The complex phenomenology of strong interacting particles had led in 1964 to the hypothesis of quarks, which was confirmed beginning of the 1970s by electron scattering off the quarks. The lecture starts from the properties of the quarks as Dirac particles, and the observable cross sections are linked to quark distribution functions, from which follows their determination by the experiment. Focus is on recent experiments, as electron scattering at DESY and myon scattering at CERN, in which the spin structure and correlations between kinematic parameters of the bound quarks are studied. The goal of the lecture is to give an insight to the quark-gluon structure of the nucleons.

With successful paticipation of the lecture, the students have

1. an overview over quark distribution functions,
2. on the theoretically formulated sum rules for the distribution functions and their experimental tests,
3. as well as an insight in more complex correlation functions, e.g. for transverse degrees of freedom.

 It may also prepare a productive and competent work within such a complex experiment.

Successful participation in a particle and quantum physics module, whose concepts will however be recapitulated.

The lecture is thematically structured, leading from general properties of bound particles to effective quantities, with analogies to atomic physics. By frequent encouragement of feedback, the students are motivated to explore the line of thought themselves, and scientific argumentation is exercised. In dedicated exercises, the understanding of the mathematical relations are deepened by using the program package "root", which is either only presented or offered to be reproduced on the student's laptops, upon interest. Important scientific developments are highlighted by a detailed study of original literature.

Slides, smartboard, moodle

Thomas, Weise: The Structure of the Nucleon, esp. chapter 4
Povh: Particles and Nuclei
Halzen, Martin: Quarks and Leptons

There will be an oral exam of about 30 minutes duration. Therein the achievement of the competencies given in section learning outcome is tested exemplarily at least to the given cognition level using comprehension questions and sample calculations.

For example an assignment in the exam might be:

• How was proven experimentally that there is scattering off quarks, and what are the relevant kinematic quantities?
• Which sum rule gives, by its violation, indications for a more complex interaction of the quarks than the usual structure functions assume?
• Which kind of measurement enables to explore the relation of form factors and structure functions, in how far are they two different ways to look at the same object?