Scattering amplitudes from finite-volume spectral functions

John Bulava*, Maxwell T. Hansen

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Abstrakt

A novel proposal is outlined to determine scattering amplitudes from finite-volume spectral functions. The method requires extracting smeared spectral functions from finite-volume Euclidean correlation functions, with a particular complex smearing kernel of width ϵ which implements the standard iϵ prescription. In the L→∞ limit these smeared spectral functions are therefore equivalent to Minkowskian correlators with a specific time ordering to which a modified Lehmann-Symanzik-Zimmermann reduction formalism can be applied. The approach is presented for general m→n scattering amplitudes (above arbitrary inelastic thresholds) for a single-species real scalar field, although generalization to arbitrary spins and multiple coupled channels is likely straightforward. Processes mediated by the single insertion of an external current are also considered. Numerical determination of the finite-volume smeared spectral function is discussed briefly and the interplay between the finite volume, Euclidean signature, and time-ordered iϵ prescription is illustrated perturbatively in a toy example.

OriginalsprogEngelsk
Artikelnummer034521
TidsskriftPhysical Review D
Vol/bind100
Udgave nummer3
Antal sider20
ISSN2470-0010
DOI
StatusUdgivet - 1. aug. 2019

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