Free Meson Seminars
The meson spectrum of large-N QCD
by Prof. Gunnar Bali (Universitat Regensburg)
Thursday, February 14, 2013
from
to
(Asia/Kolkata)
at Colaba Campus ( AG69 )
at Colaba Campus ( AG69 )
Description |
QCD is the quantum field theory of the strong interactions. It is based on an SU(N) gauge symmetry with the number of colours N=3, coupled to fermions in the fundamental representations. In the limit of infinite N this theory simplifies. For instance all physical amplitudes are given by a subset of only planar Feynman diagrams. Moreover, keeping the number of fermion flavours fixed (the so-called 't Hooft limit), the effect of sea quarks can be neglected, reducing QCD to a quenched but unitary model. In this limit the spectrum consists of stable glueballs and mesons. Nevertheless this limit is still non-perturbative and far from trivial. Phenomenologically, it is a good starting point to investigations of strong decays, e.g., within the framework of effective field theories. From the theoretical side, the large-N limit of strongly coupled (SUSY-)QCD is conjectured to be dual to classical supergravity in an anti-de-Sitter background (AdS/QCD correspondence), allowing for non-perturbative calculations, preserving the rotational symmetry. I will summarize recent results from our lattice simulations of the meson spectrum and decay constants in the large-N limit of QCD and compare these to real world QCD as well as to phenomenological and string theory expectations. |