Precision physics with pile-up insensitive observables

TL;DR

This paper demonstrates that soft drop jet grooming is theoretically robust and effective for precision measurements at the LHC, even under high pile-up conditions, enabling more accurate comparisons between theory and experimental data.

Contribution

It provides a detailed theoretical analysis of soft drop jet grooming, showing it is free of non-global logarithms and suitable for high-precision QCD calculations at NNLL accuracy.

Findings

Soft drop jet mass calculated at NNLL+NNLO accuracy.

Method is ultra-local and pile-up insensitive.

Enables precise theory-data comparisons regardless of pile-up.

Abstract

To deepen the search for beyond the Standard Model physics, the Large Hadron Collider is pushing to higher and higher luminosity. At high luminosity, precision physics becomes increasingly difficult due to contamination from additional proton collisions per bunch crossing called pile-up. In recent years, many methods have been developed to cull this excess mostly low-energy radiation away from important signal regions, but it has been unclear if these methods were amenable to systematically-improvable theoretical understanding. In this paper, it is shown that one such method, soft drop jet grooming, has excellent theoretical properties: it is ultra-local, depending on only radiation within a jet, and it is free of non-global logarithms. Calculations of the soft drop jet mass and related observables are presented at next-to-next-to-leading logarithmic accuracy matched to next-to-next-to-leading fixed-order in perturbative Quantum Chromodynamics. Once measured at the Large Hadron Collider, precision comparisons between theory and data can be made, essentially independent of the amount of pile-up contamination.