Thompson Rivers University

Science Seminar Series: Exotic Hadrons and QCD Sum Rules

Dr. Robin Kleiv of TRU’s physics department presents Exotic Hadrons and QCD Sum Rules as part of the Science Seminar Series.

What the talk is about

In this talk Dr. Kleiv gives an overview of hadronic physics and QCD sum rules, and discusses recent and current research he is involved in.


Protons and neutrons are held together inside atomic nuclei by the strong nuclear force, which, on a more fundamental level, binds quarks together inside protons and neutrons themselves.

The strong nuclear force is described in terms of quantum chromodynamics (QCD),  within which interactions between quarks are mediated by the exchange of particles called gluons. Bound states of quarks and gluons are called hadrons. Examples are the proton and neutron, each of which is composed of three quarks. However, more unusual hadrons are permitted to exist by QCD, including those composed of four quarks (tetraquarks or meson molecules), gluons only (glueballs), and both quarks and gluons (hybrids).

Such so-called exotic hadrons have not yet been conclusively identified experimentally although there are a number of tantalizing candidates.

My collaborators and I utilize a technique called QCD sum rules to calculate the physical properties of hadrons, helping to ascertain the identities of several recently observed, possibly exotic hadrons.

This work complements current and future experimental efforts aimed at discovering new particles.