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European Network

The Transverse Structure of the Proton (Transnet)

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This is the Webpage of the European Network "The Transverse Structure of the Proton". The network consists of 8 participating nodes, divided over eight countries (see the map below the main directory).

This network is proposed to the European Commission for approval as an Marie Curie Initial Training Network (ITN) under call FP7-PEOPLE-2007-1-1-ITN. The network will be proposed for a a duration of 48 months. Further details on the ITN programme and other networks may be found at http://cordis.europe.eu/fp7/home_en.html.

Main Directory:

- Proposal NEW 
- General Information (A1)
- Information on Organisations (A2-forms) [Amsterdam, Bochum, Hamburg, Helsinki, Krakow, Palaiseau, Pavia, Torino]
- Requested Fellows (A4)
-Outline  Proposal  (Part B)
- Research Objectives

- Training Content

- Management

- Major Tasks:

- Distribution functions (DFs) and Fragmentation functions (FFs)
- Generalised Parton Distributions (GPDs)
- Gluon Phenomena


-Calendar: 

- Positions for Early Stage Researchers (ESRs)

- Reports

- Useful links 

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In the future we will provide information about the participating organizations upon clicking on the map:

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Latest News

The preprosal has been submitted on May 6, 2007.
At the end of July 2007 we have received the news that the preproposal has not been selected for further consideration in this round.

Abstract

In the programme we study aspects of the quark and gluon structure of hadrons and its implications in related fields. Quantum chromodynamics (QCD) is the theory that describes the strong interactions of quarks and gluons, the constituents of hadrons, such as the protons and neutrons (nucleons) that form all the atomic nuclei. Although the microscopic theory is known, its consequences are far from being understood; this is evident when it comes to understanding the outcome of experiments involving hadrons. In the proposed programme, early-stage researchers will be trained to solve outstanding open questions on the transverse structure of hadrons, where polarization and intrinsic motion of the constituents play a role. Experimental activities on hadron physics are done in worldwide collaborations at a number of large-scale and smaller-scale facilities in Europe, the USA and Japan. Theoretical activities are pursued in a large number of universities and research institutes. European physicists are key players in many of these collaborations. Right now, with the start of the Large Hadron Collider at CERN, physicists will be able to probe deeper into matter and forces than ever before and a transfer of knowledge and expertise in many areas is vital, one of them being the QCD structure of hadrons. This proposal intends to build and strengthen the interactions between experiment and theory through a well-structured programme of training and knowledge transfer activities. The early-stage researchers will work within groups that engage in research at the forefront of hadron physics covering a broad spectrum of research topics. The researchers will learn a variety of experimental, analytical, computational and theoretical research methods from experienced leading researchers in nuclear physics, particle physics and astrophysics; they will acquire skills that are important not only in state-of-the-art research but also in many other high technology sectors of our society.

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Research Objectives (see part B for details)

Quantum Chromo Dynamics (QCD) is the theory of the strong interactions, the force that is responsible for the binding of the elementary colored constituents, quarks and gluons, into observable hadrons and for the interactions between these hadrons. The framework of QCD is well-developed, but several open issues remain, such as the confinement and the quark and gluon structure of protons and neutrons, including their spin and orbital composition. A first feature in exploring the hadronic structure in terms of its elementary constituents is the necessity to use high energy scattering processes. This eliminates effectively all binding effects in one direction, the direction of motion. The resulting collinear free behavior of fast moving quarks and gluons is essential for understanding and interpreting experiments at high-energy hadron colliders such as the soon to be operational Large Hadron Collider (LHC) and is described with the help of non perturbative distribution and fragmentation functions. The high-energy scale not only defines the maximal mass of particles to be created or the smallest distance in the study of forces, but it also provides an expansion parameter. While the high-energy hadrons are boosted into pancakes in the longitudinal direction, sizes are not affected in the transverse directions. By selecting the right observables in high energy processes, e.g. azimuthal asymmetries, one can isolate and look at transverse momenta or transverse spin degrees of freedom; this allows the study of fundamental intrinsic properties and correlations of quark and gluons. The orbital motion of quarks inside a proton would be a striking example. Another interesting hadronic phenomenon is a strong increase with energy in the number of (soft) gluons, which may lead to new phenomena such as the formation of a color glass condensate. Finally, even in high energy processes, exclusive phenomena remain, including diffractive events. They investigate unique features of the structure of hadrons, in the framework of QCD, in terms of partonic correlation functions, generalized parton distributions or a color dipole picture. Progress is the result of the interplay between the experimental efforts at large and medium-scale facilities and the theoretical approaches based on models or lattice gauge calculations.


Training Content (see part B for details)

The network is focused on the study of the internal structure of protons and neutrons, and, in general, of hadrons. It combines different approaches, theoretical, phenomenological and experimental, in a field - hadron physics - for which a broad training programme including experimental and theoretical aspects is quite natural. It is here where the strength of the collaborating teams shows up. They have expertise in particle physics phenomenology and they will, organised around eight nodes, create a strong network, intermediating between experimentalists at large and medium-scale facilities and theoretical groups that use more mathematically or computationally oriented methods. The involvement of many of the participants in national training programmes enables them to use those excellent infrastructures in order to create a training environment for a European network of early-stage researchers (ESRs). The important added value from the network consists in the focused and coherent efforts that provide these early-stage researchers with skills that can be used worldwide in state-of-the-art research centres as well as in other high technology sectors of society, such as industrial research labs, medical imaging, information technology or finance.

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Management

Network coordinator:


Steering Committee:


Supervisory Board:


Coordinators of network partners

  1. Amsterdam: Piet Mulders (VU, Amsterdam), mulders@few.vu.nl
  2. Bochum: maxim.polyakov, maxim.polyakov@tp2.rub.de
  3. Hamburg: Markus Diehl, markus.diehl@desy.de
  4. Helsini: Paul Hoyer, paul.hoyer@helsinki.fi
  5. Krakow: Krzysztof Golec-Biernat, golec@ifj.edu.pl
  6. Palaiseau, Bernard Pire, bernard.pire@cpht.polytechnique.fr
  7. Pavia: Sigfrido Boffi, sigfrido.boffi@pv.infn.it
  8. Torino: Mauro Anselmino, mauro.anselmino@to.infn.it
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Major Tasks (see part B for details):

The project has been broken up into three main work tasks.

  • Distribution functions (DFs) and fragmentation functions (FFs)
  • In this work package the central point is the phenomenology of distribution functions (DFs) and fragmentation functions (FFs). They form the basic link between experiments and theory, appearing on the one hand in explicit expressions for observables and on the other hand having a well-defined definition in terms of quark and gluon fields in the QCD framework. Emphasis is on the rich structure in these functions if one includes the transverse momenta of partons as well as the spin degrees of freedom. The quantities are forward matrix elements of operators in contrast to the generalised parton distributions, which constitute off-forward matrix elements (link to WP-3). In applications at higher energies, one certainly needs a stronger emphasis on gluon DFs and FFs and their mixing with the quark functions (link to WP-4).
    (teams: Torino, Amsterdam, Bochum, Hamburg, Palaiseau, Pavia).

  • Generalised Parton Distributions (GPDs)
  • The DFs and FFs are the important issues in inclusive and semi-inclusive measurements (in the latter case identifying one or two particles in an inclusive background), but exclusive phenomena remain important even at very high energies. Experimental signatures are the production of identifiable electroweak particles (photons, W or Z-bosons) or the production of isolated (fast) hadrons, e.g. pions. Also here one can link the observables to well-defined matrix elements, in this case off-forward. These generalised parton distributions (GPDs) require more work in the stage of analysing data, because the number of variables involved is larger. But after the analysis the reward is a link to either DFs or to basic properties such as orbital angular momentum of partons, which cannot be accessed in any other way. Via other exclusive phenomena (such as diffraction) one has a natural link to gluons (WP-4).
    (teams: Bochum, Hamburg, Helsinki,Krakow, Palaiseau, Pavia, Torino)

  • Gluon Phenomena
  • Gluons merit a separate work package, because their self-coupling is one of the most distinctive properties of QCD. Not only are gluons an extension of the other work packages, but they dominate the dynamics of collisions at high energy. In particular, the growth of the number of gluons as 'seen' in high-energy experiments leads to the expectation that one will reach a regime of saturation at low momentum fractions x in the DFs, possibly accompanied by new phenomena such as a color glass condensate. For the latter, signatures at the LHC may require dedicated experimental efforts, e.g. polarimetry.
    (teams: Krakow, Amsterdam, Bochum, Hamburg, Helsinki)

    These three tasks represent three complementary ways to attack the problem of the short distance structure of hadronic matter. Collaboration of teams which have already made significant contributions to the field is mandatory to address such a challenging issue, and is the optimal place to train researchers entering in this area.

    Some publications (recent collaborative efforts or high-impact papers)

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    Reports

    No annual reports have yet been produced

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    Useful links

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    These pages are currently maintained by Marja Koopmans, secretary of  Theoretical Physics, Vrije Universiteit Amsterdam.
    Sent mail to: mkoopmans@few.vu.nl. Comments are appreciated.

    Last modified: Sunday May 6