Bottom-Up Reconstruction Scenarios for (un)constrained MSSM Parameters at the LHC

TL;DR

This paper develops bottom-up reconstruction methods for MSSM parameters at the LHC, using limited measurements and analytical relations, providing a complementary approach to traditional top-down fits.

Contribution

It introduces step-by-step analytical algorithms for MSSM parameter reconstruction from LHC data, including radiative corrections and comparison with top-down methods.

Findings

Reconstruction algorithms for MSSM parameters from limited LHC data.

Comparison between bottom-up and top-down parameter determinations.

Implementation of bottom-up RGE evolution in the SuSpect code.

Abstract

We consider some specific inverse problem or "bottom-up" reconstruction strategies at the LHC for both general and constrained MSSM parameters, starting from a plausibly limited set of sparticle identification and mass measurements, using mainly gluino/squark cascade decays, plus eventually the lightest Higgs boson mass. For the three naturally separated sectors of: gaugino/Higgsino, squark/slepton, and Higgs parameters, we examine different step-by-step algorithms based on rather simple, entirely analytical, inverted relations between masses and basic MSSM parameters. This includes also reasonably good approximations of some of the relevant radiative correction calculations. We distinguish the constraints obtained for a general MSSM from those obtained with universality assumptions in the three different sectors. Our results are compared at different stages with the determination from more standard "top-down" fit of models to data, and finally combined into a global determination of all the relevant parameters. Our approach gives complementary information to more conventional analysis, and is not restricted to the specific LHC measurement specificities. In addition, the bottom-up renormalization group evolution of general MSSM parameters, being an important ingredient in this framework, is illustrated as a new publicly available option of the MSSM spectrum calculation code "SuSpect".