Anatomy of real intermediate state-subtraction scheme

Author:

Kalle Ala-Mattinen, Matti Heikinheimo, Kimmo Kainulainen, Kimmo Tuominen

Keyword:

High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), Cosmology and Nongalactic Astrophysics (astro-ph.CO)

journal:

HIP-2023-14/TH

date:

2023-09-27 16:00:00

Abstract

We study the origin of the real intermediate state subtraction problem and compare its different solutions. We show that the ambiguity in subtraction schemes arises from the on-shell approximation for the 2-point functions that reduces the Schwinger-Dyson equations to the Boltzmann limit. We also suggest a new subtraction scheme which, unlike the earlier definitions, never leads to negative scattering rates. This scheme also quantifies the validity of the on-shell limit in terms of an effective one-particle weight function $R(\Delta )$, where $\Delta$ measures the region around the resonance associated with the real state.

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