Physics impact of a precise determination of the top quark mass at an e⁺e⁻linear collider

Abstract

At a prospective e + e − Linear Collider (LC) a very precise determination of the top quark mass with an accuracy of δm t 100 MeV will be possible. This is to be compared with the envisaged accuracy of δm t = 1-2 Gev at the Tevatron and the LHC. We discuss the physics impact of such a precise determination of m t , focusing on the Standard Model (SM) and its minimal supersymmetric extension (MSSM). In particular, we show the importance of a precise knowledge of m t for electroweak precision observables, and for Higgs physics and the scalar top sector of the MSSM. Taking the mSUGRA model as a specific example, we furthermore demonstrate the importance of a precise m t value for the prediction of sparticle masses and for constraints on the parameter space allowed by the relic density. The uncertainty in m t also significantly affects the reconstruction of the supersymmetric high scale theory. We find that going from hadron collider to LC accuracy in m t leads to an improvement of the investigated quantities by up to an order of magnitude.

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“…For definiteness, we will usem = 10 9 GeV, while M g is let free. Now we focus on the comparison for M W and sin 2 θ eff predictions from different models [15,16]. Our results agree with previous ones for the SM and the MSSM predictions given in [14].…”

“…We focus on the comparison of Split SUSY predictions with the SM and MSSM predictions, by considering the present data and the prospective experimental precision at the next generation of colliders. Even if the regions of parameter space allowed by colliders constraints is expected to be allowed by precision electroweak constraints in Split SUSY [10,12], an analysis of these two observables, which are very precisely determined by experiments [15,16], has not yet been done, and could provide extra information about the compatibility and/or similarities and differences between Split SUSY predictions on these two EW precision observables and the SM and MSSM predictions. A few more words are in order with respect the recent analysis in Refs.…”

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