Triple-collinear splittings with massive particles

TL;DR

This paper derives compact formulas for triple-collinear splittings involving massive particles, crucial for high-precision collider predictions, extending known massless results to include mass effects.

Contribution

It provides the first detailed analysis and explicit expressions for triple-collinear splitting amplitudes with massive particles, enhancing precision in collider calculations.

Findings

Expressions agree with massless limits

Quantify mass effects in observables

Essential for high-precision collider frameworks

Abstract

We analyze in detail the most singular behaviour of processes involving triple-collinear splittings with massive particles in the quasi-collinear limit, and present compact expressions for the splitting amplitudes and the corresponding splitting kernels at the squared-amplitude level. Our expressions fully agree with well-known triple-collinear splittings in the massless limit, which are used as a guide to achieve the final expressions. These results are important to quantify dominant mass effects in many observables, and constitute an essential ingredient of current high-precision computational frameworks for collider phenomenology.