Z-Boson Decays in a Strong Electromagnetic Field

TL;DR

This paper calculates how a strong electromagnetic field influences Z-boson decay probabilities, revealing that intense fields can significantly alter decay widths and enable processes like t-quark production that are forbidden in vacuum.

Contribution

It provides exact analytic expressions for Z-boson decay widths in arbitrary electromagnetic fields, including the effects of all known charged fermion generations.

Findings

Field-induced corrections are within 2% for weak fields.

Decay width oscillates and decreases with increasing field strength.

Strong fields enable t-quark production in Z-boson decay.

Abstract

The probability of Z-boson decay to a pair of charged fermions in a strong electromagnetic field, is calculated. On the basis of a method that employs exact solutions to relativistic wave equations for charged particles, analytic expressions for the partial decay widths of Z-boson are obtained at an arbitrary value the external-field strength. The total Z-boson decay width in an intense electromagnetic field, is calculated by summing these results over all known generations of charged leptons and quarks. It is found that, in the region of relatively weak fields, the field-induced corrections to the standard Z-boson decay width in a vacuum do not exceed 2%. As the external-field strength increases, the total decay width develops oscillations against the background of its gradual decrease to the absolute-minimum point. In the region of strong fields the total decay width of Z-boson grows monotonically. In this case the t-quark-production process, which is forbidden in the absence of an external field, begins contributing significantly to the total decay width of the Z-boson.