The littlest Higgs is a cruiserweight

Abstract

We study the exact (one-loop) effective potential of the littlest Higgs model and determine the dependence of physical quantities, such as the vacuum expectation value v_W and mass m_h of the Higgs boson, on the fundamental parameters of the Lagrangian--masses, couplings of new states, the fundamental scale f of the sigma model, and the coefficients of operators quadratically sensitive to the cutoff of the theory. On the one hand, we show that it is possible to have the electroweak ground state and a relatively large cutoff Λ= 4πf with f in the 2 TeV range without requiring unnaturally small coefficients for quadratically divergent quantities, and with only moderate cancellations between the contribution of different sectors to the effective potential of the Higgs. On the other hand, this cannot be achieved while at the same time keeping m_h close to its (bantamweight) current lower bound of 114.4 GeV. The natural expectation for m_h is O(f), mainly because of large logarithmically divergent contributions to the effective potential of the top-quark sector. Even a fine-tuning at the level of O(10^{-2}) in the coefficients of the quadratic divergences is not enough to produce small physical Higgs masses, and the natural expectation is in the 800 GeV range (cruiserweight) for f \sim 2 TeV. We conclude that the littlest Higgs model is a solution of the little hierarchy problem, in the sense that it stabilizes the electroweak symmetry breaking scale to be a factor of 100 less than the cutoff of the theory, but this requires a quite large physical mass for the Higgs, and hence precision electroweak studies should be redone accordingly. We also study finite temperature corrections.

18 pages, 9 figures, RevTex4. Final version accepted for publication in Phys. Rev. D

References in corpus (35)

• Big Bang Nucleosynthesis (in "The Review of Particle Properties" 2004)
• The Minimal Composite Higgs Model
• Electroweak symmetry breaking from dimensional deconstruction
• The Littlest Higgs
• The Minimal Moose for a Little Higgs
• Higgs as a Holographic Pseudo-Goldstone Boson
• TeV Symmetry and the Little Hierarchy Problem
• Phenomenology of the Little Higgs Model
• Little Hierarchy, Little Higgses, and a Little Symmetry
• Little Higgses from an Antisymmetric Condensate
• Big Corrections from a Little Higgs
• Variations of Little Higgs Models and their Electroweak Constraints
• The Little Higgs from a Simple Group
• Constraining the Littlest Higgs
• One-loop Radiative Corrections to the rho Parameter in the Littlest Higgs Model
• The Simplest Little Higgs
• A "Littlest Higgs" Model with Custodial SU(2) Symmetry
• The Low-Energy Structure of Little Higgs Models
• Little Higgs and Custodial SU(2)
• Introducing the Little Higgs
• How Can a Heavy Higgs Boson be Consistent with the Precision Electroweak Measurements?
• A Simple Model of two Little Higgses
• Little-Higgs corrections to precision data after LEP2
• Implications for New Physics from Fine-Tuning Arguments: I. Application to SUSY and Seesaw Cases
• Unitarity of Little Higgs Models Signals New Physics of UV Completion
• Little Higgs Models and Precision Electroweak Data
• Implications for New Physics from Fine-Tuning Arguments: II. Little Higgs Models
• Symmetry Nonrestoration at High Temperature in Little Higgs Models
• The Littlest Higgs in Anti-de Sitter Space
• Little Technicolor
• Fermion Masses and Mixings in the Little Flavon Model
• The little flavons
• Phenomenology of the little flavon model
• A heavy Higgs boson from flavor and electroweak symmetry breaking unification
• Flavor and electroweak symmetry breaking at the TeV scale

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• Radiative corrections to the Higgs potential in the LH model
• Composite Higgs Models with a Hidden Sector
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