Critical constraints on chiral hierarchies

Oct, 1992
10 pages
Published in:
  • Phys.Rev.Lett. 70 (1993) 1587-1590
e-Print:
Report number:
  • BUHEP-92-35,
  • HUTP-92-A058

Citations per year

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Abstract:
We consider the constraints that critical dynamics places on models with a top quark condensate or strong extended technicolor (ETC). These models require that chiral-symmetry-breaking dynamics at a high energy scale plays a significant role in electroweak symmetry breaking. In order for there to be a large hierarchy between the scale of the high energy dynamics and the weak scale, the high energy theory must have a second order chiral phase transition. If the transition is second order, then close to the transition the theory may be described in terms of a low-energy effective Lagrangian with composite ``Higgs'' scalars. However, scalar theories in which there are more than one Φ 4\Phi~4 coupling can have a {\it first order} phase transition instead, due to the Coleman-Weinberg instability. Therefore, top-condensate or strong ETC theories in which the composite scalars have more than one Φ 4\Phi~4 coupling cannot always support a large hierarchy. In particular, if the Nambu--Jona-Lasinio model solved in the large-NcN_c limit is a good approximation to the high-energy dynamics, then these models will not produce acceptable electroweak symmetry breaking.
  • phi**n model: 4
  • critical phenomena: hierarchy
  • symmetry breaking: chiral
  • electroweak interaction: symmetry breaking
  • symmetry breaking: electroweak interaction
  • symmetry: U(N) x U(N)
  • top: condensation
  • model: technicolor