T. Appelquist and S. Selipsky, Phys. Lett. B400 (1997) 364, hep-ph/9702404.  Home/Search   Document Not in Database   Summary   Related Articles   Check

.... N c f ) no light degrees of freedom are formed as N f N c f . Thus the transition is continuous but not conventionally second order. The validity of the approach is considered by estimating higher order terms in both the fi function and the anomalous dimension of the mass operator. In Ref. [33], it was noted that single instanton effects in a theory with an infrared fixed point seem capable of triggering a chiral phase transition at similarly large values of N f =N . A detailed computation was carried only out for an SU(2) gauge theory but the analysis indicated that this could be the ....

T. Appelquist and S. Selipsky, Phys. Lett. B400 (1997) 364, hep-ph/9702404.

....of N f is of theoretical interest, but is unlikely to shed direct light on the physics of the real world. There remains the possibility, however, that if technicolor is the correct 3 framework for electroweak symmetry breaking, the transition could be physically relevant. In a recent letter [10], it was pointed out that in an SU(2) technicolor theory, a single family of techniquarks (N f = 8) leads to an infrared fixed point near the critical coupling for the chiral phase transition. This can provide a natural origin [11] for walking technicolor [12] and has other interesting ....

....light degrees of freedom (other than quarks and gluons) exist in the symmetric phase Within this general picture, it is important to describe the spectrum of resonances in more detail. If, for example, a near critical theory is the basis for a technicolor theory of electroweak symmetry breaking [10], then the the light scale Sigma(0) will correspond to the electroweak scale and the spectrum of resonances at this scale will have a direct impact on precision electroweak measurements. In particular, the S parameter [30] will depend sensitively on this spectrum. An especially interesting ....

T. Appelquist, J. Terning, and L.C.R. Wijewardhana, Phys. Rev. Lett. 79 (1997) 2767, hep-ph/9706238.

....ff increases. At some critical value of N f (N c f ) there will be a phase transition to the chirally asymmetric and confined phase. It is an important problem in the study of gauge field theories to determine N c f and to characterize the nature of the phase transition. In a recent letter [4], we suggested that the phase transition takes place at a large enough value of N c f so that the infrared fixed point ff reliably exists and governs the phase transition. The transition was then analyzed using the ladder expansion of a gap equation, or equivalently the CJT effective potential ....

....be shown that when the coupling exceeds this critical value, the CJT effective potential [5] becomes unstable at the origin, indicating that a chirally asymmetric solution is energetically favored and therefore represents the ground state of the theory. Setting ff equal to ff c gives an estimate [4] of the critical number of flavors N c f = N 100N 2 Gamma 66 25N 2 Gamma 15 ; 14) above which there is no chiral symmetry breaking. Note that the ratio N c f =N is predicted to be very close to 4 for all N . We next discuss the critical behavior at this transition. Since the ....

T. Appelquist, J. Terning, and L.C.R. Wijewardhana, Phys. Rev. Lett. 77 (1996) 1214 hep-ph/9602385.

....QCD in perturbation theory for F below and sufficiently close to 33=2. Presumably such fixed point behavior persists as F is reduced down to some critical value F crit . Assuming that chiral symmetry breaking 1 marks the end of the fixed point regime, Appelquist, Wijewardhana, and I estimated [7] this critical value to be F crit 4N c = 12. Lattice Monte Carlo studies [9] suggest that F crit 8. Whatever the precise value of F crit is, for F in the range F crit F 33=2 it seems worthwhile to consider a generalized t Hooft problem: is there a gauge theory coupled to composite ....

T. Appelquist, J. Terning, and L.C.R. Wijewardhana, Phys. Rev. Lett. 77 (1996) 1214, hep-ph/9602385.

....models are incompatible with the experimental values of S and T [10] or corrections to the Zb b vertex [11] due to the difficulties inherent in performing reliable calculations in a strongly interacting theory. An attempt in this direction was made recently by Appelquist and Terning [12]. They constructed an ETC model and used it to produce a wide range of fermion masses. They also argued how the model could be compatible with experimental constraints such as the value of S, FCNC and small neutrino masses. In this paper, we will begin by demonstrating the existence of two ....

.... Q = T 3L Y=2) is given by Y = QR T PS 15 , where T PS 15 = diag(1=3; 1=3; 1=3; Gamma1) is a generator of the SU(4)PS Pati Salam group which implements quark lepton unification (For details regarding the motivation for the choice of the gauge group and fermion representation content see [12]) At the Pati Salam breaking scale (taken to be around 1000 TeV ) a condensate is assumed to form in the channel (5; 1; 4; 1) Gamma1 Theta (5; 1; 1; 1) 0 (1; 1; 4; 1) Gamma1 . This channel (h 3 7 i 6= 0) is not the most attractive Channel (MAC) 13] Instead, new physics is presumed to ....

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T. Appelquist and J. Terning, YCTP-P21-93 BUHEP-93-23, hep-ph/9311320

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