Non-Perturbative Approaches to Hadron Interactions in Quantum
Chromodynamics
ABSTRACT
2011 National Grants
Mechanical Engineering
Quantum chromodynamics (QCD) is the theory that explains the dynamics and interactions of quarks, which are one of the
fundamental particles of matter, in terms of gluon exchanges. Quarks, which carry one of the three color charges (red, green
or blue), cannot exist as free particles. However, quarks combine so as to form colorless hadrons (mesons as quark—antiquark and baryons as three quark states) such as the proton and the neutron or those that can be observed via high-energy
and nuclear physics experiments. The hadronic sector is composed of light u, d, s and heavy c, b, t quark flavors. The
lightest quarks u and d have masses of the order of a few MeV, whereas the strange (s) quark has a mass around 150 MeV.
As compared to the typical hadron mass scale (~1 GeV), one can assume an approximate SU(3) symmetry [flavor-SU(3)]
between the u, d and s quarks. The interactions of hadrons have long been studied both theoretically and experimentally
as they provide key answers with regard to fundamental structure of matter and the symmetries of nature. One important
issue in LHC is to understand the QCD background. While there are some model-dependent approaches in the literature,
hadronic interactions are in principle explained by QCD. Such a first-principles description of the hadron-hadron interaction,
however, is highly complicated, particularly at low energy, where QCD is a non-perturbative theory. Two of the approaches
that are commonly used in this framework are the methods of QCD sum rules and lattice QCD. The QCD sum rules method
is a powerful tool to extract qualitative and quantitative information about hadron properties. For this reason it has been
extensively applied in the literature to analyze various problems. In this method one uses an analytical technique to match
the behaviors of hadrons at high and low energies. This matching then allows us to obtain the characteristic properties of
hadrons as obtained directly from QCD. The information obtained though this method has long been used as an input for
other theoretical approaches and experimental efforts. Lattice QCD is another approach which offers a method of calculating
hadronic observables. It allows us to obtain information about hadron properties starting from first principles and without
making any model-dependent assumptions. In this technique, QCD is formulated on a space-time lattice and the resulting
equations are solved numerically on a computer. Lattice QCD has proved to be rather successful in predicting the spectral
properties of mesons and baryons, as well as the parameters characterizing their interactions. The goal of this project is
to determine the spectrum and the interactions of octet and decuplet baryons. In particular, we aim to concentrate on the
axial and the electromagnetic charges together with the form factors of baryons. For this purpose we are going to utilize the
method of QCD sum rules and lattice QCD. A determination of these parameters will provide precious information about
the structure of baryons and will allow us to explore the strangeness sector and to check whether flavor-SU(3) is a good
symmetry of nature or not. Our work will be compared and provide input to other theoretical approaches and to experimental
efforts.
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Doç. Dr.
Güray Erkol
DEPARTMENT
Mechanical Engineering
CONTACT
[email protected]
FUNDING SCHEME
TÜBİTAK 1001
START DATE
01.01.2011
DURATION
36 months
OZU BUDGET
280,730.00 TL