Virtual and real processes, the K\"all\'en function, and the relation to dilogarithms

TL;DR

This paper explores the connection between the K"allén function, which differentiates virtual and real processes with massive particles, and dilogarithms that appear in loop calculations in particle physics.

Contribution

It clarifies the relationship between the K"allén function and dilogarithms, providing a simpler way to analyze virtual and real processes involving massive particles.

Findings

The K"allén function effectively distinguishes virtual from real processes.

Dilogarithms naturally arise in loop calculations for these processes.

The paper offers a new perspective on analyzing particle interactions.

Abstract

We enlighten relations between the K\"all\'en function, allowing in a simple way to distinguish between virtual and real processes involving massive particles, and the dilogarithms occurring as results of loop calculations for such kind of processes.