Measuring Higgs Branching Ratios and telling the SM from a MSSM Higgs Boson at the e+e- Linear Collider

An accurate determination of the Higgs decay branching ratios to bb, cc, gg, WW* and tau tau pairs is important for the study of the Higgs couplings and for determining its SM or MSSM nature in the mass range 100 GeV/c2 < M_H < 140 GeV/c^2. This measurement also represents an important benchmark for the optimisation of the detector design. The accuracy on the determination of the Higgs decay branching ratio to fermions and WW* pairs has been studied using the simulation of the detector designed for the TESLA e+e- linear collider at c.m. energy of 350 GeV and 500 GeV. The results are discussed in terms of the ability of discriminating between the SM and a MSSM neutral Higgs boson and of the predictivity on the A boson mass in the MSSM scenario.