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Full-Text Articles in Quantum Physics
Relativistic, Model-Independent, Multichannel 2 → 2 Transition Amplitudes In A Finite Volume, Raúl A. Briceño, Maxwell T. Hansen
Relativistic, Model-Independent, Multichannel 2 → 2 Transition Amplitudes In A Finite Volume, Raúl A. Briceño, Maxwell T. Hansen
Physics Faculty Publications
We derive formalism for determining 2+𝓙 → 2 infinite-volume transition amplitudes from finite-volume matrix elements. Specifically, we present a relativistic, model-independent relation between finite-volume matrix elements of external currents and the physically observable infinite-volume matrix elements involving two-particle asymptotic states. The result presented holds for states composed of two scalar bosons. These can be identical or nonidentical and, in the latter case, can be either degenerate or nondegenerate. We further accommodate any number of strongly coupled two-scalar channels. This formalism will, for example, allow future lattice QCD calculations of the ρ-meson form factor, in which the unstable nature of …
𝜋𝜋 → 𝜋𝛾* Amplitude And The Resonant 𝜌 → 𝜋𝛾* Transition From Lattice Qcd, Raúl A. Briceño, Jozef J. Dudek, Robert G. Edwards, Christian J. Shultz, Christopher E. Thomas, David J. Wilson
𝜋𝜋 → 𝜋𝛾* Amplitude And The Resonant 𝜌 → 𝜋𝛾* Transition From Lattice Qcd, Raúl A. Briceño, Jozef J. Dudek, Robert G. Edwards, Christian J. Shultz, Christopher E. Thomas, David J. Wilson
Physics Faculty Publications
We present a determination of the P-wave 𝜋𝜋 → 𝜋𝛾⋆ transition amplitude from lattice quantum chromodynamics. Matrix elements of the vector current in a finite volume are extracted from three-point correlation functions, and from these we determine the infinite-volume amplitude using a generalization of the Lellouch-Lüscher formalism. We determine the amplitude for a range of discrete values of the 𝜋𝜋 energy and virtuality of the photon and observe the expected dynamical enhancement due to the ρ resonance. Describing the energy dependence of the amplitude, we are able to analytically continue into the complex energy plane and from the residue …