The NMSSM Close to the R-symmetry Limit and Naturalness in h ---> aa Decays for m(a) < 2m(b)

Nov, 2006
29 pages
Published in:
  • Phys.Rev.D 75 (2007) 075019
e-Print:
Report number:
  • UCD-2006-16

Citations per year

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Abstract:
Dominant decay of a SM-like Higgs boson into particles beyond those contained in the minimal supersymmetric standard model has been identified as a natural scenario to avoid fine tuning in electroweak symmetry breaking while satisfying all LEP limits. In the simplest such extension, the next-to-minimal supersymmetric model, the lightest CP-even Higgs boson can decay into two pseudoscalars. In the scenario with least fine tuning the lightest CP-even Higgs boson has mass of order 100 GeV. In order to escape LEP limits it must decay to a pair of the lightest CP-odd Higgs bosons with Br(h -> aa)>.7 and m_a<2m_b (so that a -> \tau^+ \tau^- or light quarks and gluons). The mass of the lightest CP-odd Higgs boson is controlled by the soft-trilinear couplings, A_\lambda(m_Z) and A_\kappa(m_Z). We identify the region of parameter space where this situation occurs and discuss how natural this scenario is. It turns out that in order to achieve m_a < 2 m_b with A_\lambda(m_Z), A_\kappa(m_Z) of order the typical radiative corrections, the required tuning of trilinear couplings need not be larger than 5-10 %. Further, the necessity for this tuning can be eliminated in specific SUSY breaking scenarios. Quite interestingly, Br(h -> aa) is typically above 70 % in this region of parameter space and thus an appropriately large value requires no additional tuning.
  • 12.60.Jv
  • 14.80.Cp
  • 14.80.Ly
  • Higgs particle: hadronic decay
  • Higgs particle: branching ratio
  • pseudoscalar particle: pair production
  • Higgs particle: leptonic decay
  • tau: pair production
  • Higgs particle: mass
  • grand unified theory