Abstract
Various methods are used in the literature for predicting the lightest CP-even Higgs boson mass in the Minimal Supersymmetric Standard Model (MSSM). Fixed-order diagrammatic calculations capture all effects at a given order and yield accurate results for scales of supersymmetric (SUSY) particles that are not separated too much from the weak scale. Effective field theory calculations allow a resummation of large logarithmic contributions up to all orders and therefore yield accurate results for a high SUSY scale. A hybrid approach, where both methods have been combined, is implemented in the computer code FeynHiggs. So far, however, at large scales sizeable differences have been observed between FeynHiggs and other pure EFT codes. In this work, the various approaches are analytically compared with each other in a simple scenario in which all SUSY mass scales are chosen to be equal to each other. Three main sources are identified that account for the major part of the observed differences. Firstly, it is shown that the scheme conversion of the input parameters that is commonly used for the comparison of fixed-order results is not adequate for the comparison of results containing a series of higher-order logarithms. Secondly, the treatment of higher-order terms arising from the determination of the Higgs propagator pole is addressed. Thirdly, the effect of different parametrizations in particular of the top Yukawa coupling in the non-logarithmic terms is investigated. Taking into account all of these effects, in the considered simple scenario very good agreement is found for scales above 1 TeV between the results obtained using the EFT approach and the hybrid approach of FeynHiggs.
Highlights
The properties of the Higgs boson that has been discovered by the ATLAS and CMS collaborations at the CERN Large Hadron Collider [1,2] are compatible with those predicted for the Higgs boson of the Standard Model (SM) at the present level of accuracy
In the following we will discuss the differences between the various approaches. It is obvious from the discussion of the previous section that the diagrammatic fixed-order result and the pure effective field theory (EFT) result differ by higher-order logarithmic terms that are contained in the EFT result but not in the diagrammatic fixed-order result as well as by non-logarithmic terms that are contained in the diagrammatic fixed-order result but not in the pure EFT result
In particular we have compared pure EFT calculations with the hybrid approach, in which an explicit Feynman-diagrammatic fixed-order result is combined with the leading higher-order contributions obtained from EFT methods
Summary
The properties of the Higgs boson that has been discovered by the ATLAS and CMS collaborations at the CERN Large Hadron Collider [1,2] are compatible with those predicted for the Higgs boson of the Standard Model (SM) at the present level of accuracy. Despite this apparent success of the SM, there are several open questions that cannot be answered by the SM and ask for extended or alternative theoretical concepts. Two parameters are required to describe the Higgs sector at the tree level (conventionally chosen as tan β and the mass MA of the CP-odd Higgs particle); masses and couplings, are substantially affected by higher-order contributions
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