Hadron Resonances from QCD
1 Department of Physics, Old Dominion University, Norfolk, VA 23529 , USA
2 Theory Center, Jefferson Lab, 12000 Jefferson Avenue, Newport News, VA 23606, USA
a e-mail: email@example.com
Published online: 25 March 2016
I describe how hadron-hadron scattering amplitudes are related to the eigenstates of QCD in a finite cubic volume. The discrete spectrum of such eigenstates can be determined from correlation functions computed using lattice QCD, and the corresponding scattering amplitudes extracted. I review results from the Hadron Spectrum Collaboration who have used these finite volume methods to study ππ elastic scattering, including the ρ resonance, as well as coupled-channel πK, ηK scattering. The very recent extension to the case where an external current acts is also presented, considering the reaction πγ* → ππ, from which the unstable ρ → πγ transition form factor is extracted. Ongoing calculations are advertised and the outlook for finite volume approaches is presented.
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