New computations on scattering amplitudes illuminate quark and gluon particle interactions

A transatlantic team of researchers has provided the first calculation of the full relativistic scattering amplitude for a three-hadron system of particles, which lies at the core of outstanding questions in quantum chromodynamics. The analytical and computational methods developed in this work pave the way for future calculations in more complicated systems involving multiparticle and nuclear systems. The researchers’ findings, which support the GlueX experiment at Thomas Jefferson National Accelerator Laboratory and other programs around the world, were published in the January 2021 issue of Physical Review Letters as an Editor’s Suggestion.

The majority of visible matter in the universe is composed of quarks and gluons. Experiments at particle and nuclear physics labs around world  investigate the mass, spin, and structure of single hadrons—particles composed of quarks and gluons—as well as multihadron systems using scattering amplitudes to reconstruct and discern the internal structure of hadrons. The determination of scattering amplitudes involving two particles is fairly well established, but challenges remain for three-particle systems. The team’s work addresses challenges associated with constructing amplitudes that obey fundamental properties and symmetries consistent with relativity and quantum mechanics.

Recently in Physical Review D, the team presented the first computation of the decays of an exotic meson, a state in which the gluon degrees of freedom are manifest. This additional research predicts the existence of such a state and provides the rates for decay particle pairs. Future calculations will probe the internal structure of states of quarks and gluons through the computation of matrix elements.

This research:

Hansen, M.T., R.A. Briceño, R.G. Edwards, C.E. Thomas, and D.J. Wilson. “Energy-Dependent π+π+π+ Scattering Amplitude from QCD.” Physical Review Letters (January 2021).


Additional research:

Woss, A.J., J.J. Dudek, R.G Edwards, C.E. Thomas, and D.J. Wilson. “Decays of an exotic 1−+ hybrid meson resonance in QCD.” Physical Review D (March 2021).