Persistent fine-tuning in supersymmetry and the NMSSM

Dec, 2005
10 pages
e-Print:
Report number:
  • HUTP-05-A0052

Citations per year

20062009201220152017024681012
Abstract:
We examine the use of modified Higgs sectors to address the little hierarchy problem of supersymmetry. Such models reduce weak-scale fine-tuning by allowing lighter stops, but they retain some fine-tuning independent of the Higgs. The modified Higgs sector can also introduce model-dependent tunings. We consider the model-independent constraints on naturalness from squark, gluino, chargino and neutralino searches, as well as the model-dependent tuning in the PQ- and R-symmetric limits of the NMSSM, where cascade decays or additional quartic interactions can hide a Higgs without relying on heavy stops. Obtaining viable electroweak symmetry breaking requires a tuning of 110\sim 1-10% in the PQ limit. A large A-term is also necessary to make charginos sufficiently heavy, and this introduces an additional weak-scale tuning of 10\sim 10%. The R-symmetric limit requires large marginal couplings, a large singlet soft mass, and a tuning of 510\sim 5-10% to break electroweak symmetry. Hiding MSSM-like Higgs states below 112\approx 112 GeV requires additional tunings of A-terms at the 110\sim 1-10% level. Thus, although the NMSSM has rich discovery potential, it suffers from a unique fine-tuning problem of its own.
Note:
  • 10 pages, 6 figures, 2 tables Report-no: HUTP-05/A0052
  • supersymmetry
  • hierarchy
  • Higgs particle: heavy
  • Higgs particle: mass
  • Z0: mass
  • sparticle: heavy
  • electroweak interaction: symmetry breaking
  • strong interaction: CP
  • R parity
  • Higgs particle: cascade decay
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