The resonant π+γπ+π0\pi^+\gamma\to\pi^+\pi^0 amplitude from Quantum Chromodynamics

Jul 23, 2015
5 pages
Published in:
  • Phys.Rev.Lett. 115 (2015) 242001
  • Published: Dec 8, 2015
e-Print:
Report number:
  • JLAB-THY-15-2106,
  • DAMTP-2015-40

Citations per year

2015201820212024202502468101214
Abstract: (arXiv)
We present the first ab initio calculation of a radiative transition of a hadronic resonance within quantum chromodynamics (QCD). We compute the amplitude for πππγ\pi\pi \to \pi\gamma^\star, as a function of the energy of the ππ\pi\pi pair and the virtuality of the photon, in the kinematic regime where ππ\pi\pi couples strongly to the unstable ρ\rho resonance. This exploratory calculation is performed using a lattice discretization of QCD with quark masses corresponding to mπ400m_\pi \approx 400~MeV. We obtain a description of the energy dependence of the transition amplitude, constrained at 48 kinematic points, that we can analytically continue to the ρ\rho pole and identify from its residue the ρπγ\rho \to \pi\gamma^\star form factor.
Note:
  • V2, version accepted for publication in PRL. More references added
  • quark: mass
  • pi pi
  • photon pi
  • quantum chromodynamics
  • kinematics
  • rho(770)
  • star
  • energy dependence
  • form factor
  • lattice