Theoretical uncertainties in sparticle mass predictions from computational tools

TL;DR

The paper evaluates the current theoretical uncertainty in MSSM sparticle mass predictions by comparing four public spectrum calculators and relating differences to expected experimental accuracies at the LHC and a future Linear Collider. It shows that the theoretical uncertainty is comparable to LHC statistical errors and generally larger than LC precision, with the size of the uncertainty depending strongly on SUSY-breaking scenarios and parameter choices. Two tricky regions, large $\tan\beta$ and the focus-point regime, exhibit especially large disparities due to Yukawa coupling treatments and RG running; the study also assesses how these theoretical errors propagate into fits of high-scale SUSY-breaking parameters using LHC data and LC-relevant observables. The findings underscore the necessity of multi-code cross-checks when interpreting collider data and mapping TeV-scale measurements onto high-scale SUSY-breaking theories, and they highlight ongoing progress in reducing theory uncertainties through higher-order corrections.

Abstract

We estimate the current theoretical uncertainty in sparticle mass predictions by comparing several state-of-the-art computations within the minimal supersymmetric standard model (MSSM). We find that the theoretical uncertainty is comparable to the expected statistical errors from the Large Hadron Collider (LHC), and significantly larger than those expected from a future e+e- Linear Collider (LC). We quantify the theoretical uncertainty on relevant sparticle observables for both LHC and LC, and show that the value of the error is significantly dependent upon the supersymmetry (SUSY) breaking parameters. We also present the theoretical uncertainty induced in fundamental-scale SUSY breaking parameters when they are fitted from LHC measurements. Two regions of the SUSY parameter space where accurate predictions are particularly difficult are examined in detail: the large tan(beta) and focus point regimes.