Model independent extraction of the pole and Breit-Wigner resonance parameters

TL;DR

This paper introduces a modified Breit-Wigner formula capable of accurately describing broad resonances across a wide energy spectrum, linking traditional parameters to the pole residue phase.

Contribution

It presents a new, mathematically equivalent Breit-Wigner formulation that includes an additional resonance parameter related to the pole residue phase, applicable to broad resonances.

Findings

Successfully describes total cross sections for broad resonances

Links Breit-Wigner parameters to the pole residue phase

Applicable from light rho(770) to Z boson

Abstract

We show that a slightly modified Breit-Wigner formula can successfully describe the total cross section even for the broad resonances, from light rho(770) to the heavy Z boson. In addition to mass, width, and branching fraction, we include another resonance parameter that turns out to be directly related to the pole residue phase. The new formula has two mathematically equivalent forms: one with the pole, and the other with the Breit-Wigner parameters.