Indications of the CMSSM Mass Scale from Precision Electroweak Data

TL;DR

This paper analyzes how current electroweak precision measurements constrain the CMSSM supersymmetry scale, highlighting the impact of recent top quark mass updates and implications for future collider experiments.

Contribution

It provides a global chi^2 fit of the CMSSM parameter space incorporating recent top quark mass measurements and cosmological data, refining the expected supersymmetry mass scale.

Findings

Preference for relatively light supersymmetric masses.

Good prospects for detection at LHC and ILC.

Sensitivity of results to future top quark mass measurements.

Abstract

We discuss the sensitivities of present-day electroweak precision data to the possible scale of supersymmetry within the constrained minimal supersymmetric extension of the Standard Model (CMSSM). Our analysis is based on M_W, sin^2 theta_eff, (g-2)_mu, BR(b -> s gamma), and the lightest MSSM Higgs boson mass, M_h. We display the impact of the recent reduction in m_t from 178.0 +- 4.3 GeV to 172.7 +- 2.9 GeV on the interpretation of the precision observables. We show the currently preferred values of the CMSSM mass scale m_{1/2} based on a global chi^2 fit, assuming that the lightest supersymmetric particle (LSP) is a neutralino, and fixing m_0 so as to obtain the cold dark matter density allowed by WMAP and other cosmological data for specific values of A_0, tan beta and mu > 0. The recent reduction in m_t reinforces previous indications for relatively light soft supersymmetry-breaking masses, offering good prospects for the LHC and the ILC, and in some cases also for the Tevatron. Finally, we discuss the sensitivity of the global chi^2 function to possible future evolution in the experimental central value of m_t and its error.