arXiv subjects
Publications and source records attributed to Thomas Appelquist.
We argue that a strongly first order electroweak phase transition is natural in the presence of strong symmetry-breaking interactions, such as technicolor. We demonstrate this using an effective linear scalar theory of the symmetry-breaking sector.
We estimate the CP-violating $WWγ$ and $WWZ$ anomalous form factors, arising from CP-violating interactions in extended technicolor theories, and discuss their future experimental detectability. The electric dipole moment of the $W$ boson is found to be as large as ${\cal O}(10^{-21}) \; \mbox{$e$ cm}$. We connect the CP-odd $WWγ$ and $WWZ$ couplings to the corresponding CP-violating electroweak chiral lagrangian operators. The electric dipole moments of the neutron and the electron in technicolor theories are estimated to be as large as ${\cal O}(10^{-26}) \; \mbox{$e$ cm}$ and ${\cal O}(10^{-29}) \; \mbox{$e$ cm}$ respectively. We also suggest the potential to observe large CP-violating technicolor effects in the decay $t \rightarrow b + W^+$.
We investigate the chiral phase transition in 2+1 dimensional QED. Previous gap equation and lattice Monte-Carlo studies of symmetry breaking have found that symmetry breaking ceases to occur when the number of fermion flavors exceeds a critical value. Here we focus on the order of the transition. We find that there are no light scalar degrees of freedom present as the critical number of flavors is approached from above (in the symmetric phase). Thus the phase transition is not second order, rendering irrelevant the renormalization group arguments for a fluctuation induced transition. However, the order parameter vanishes continuously in the broken phase, so this transition is also unlike a conventional first order phase transition.
An extended technicolor model is constructed. Quark and lepton masses, spontaneous CP violation, and precision electroweak measurements are discussed. Dynamical symmetry breaking is analyzed using the concept of the BIG MAC.
Using Big Bang Nucleosynthesis limits on the number of light neutrinos we derive a cosmological lower bound of $\approx 2$ TeV on the scale of extended technicolor interactions (or any other new interactions) for the third family in models where heavy gauge bosons couple to both left and right-handed neutrinos.
We describe how isospin splitting and techniquark-technilepton splitting in one-family technicolor models can reduce the predicted value of the electroweak radiative correction parameter S, without making a large contribution to the T parameter.
We consider the relation between the breakdown scale of chiral perturbation theory, $Λ_χ$, for large values of $N$ (flavor), and the scale associated with ``new" physical thresholds. This question is addressed using both the linear $σ$ model and an asymptotically-free gauge theory to describe the high energy dynamics. It is suggested that the massive physical threshold could be well above $Λ_χ$.
It is shown that a technicolor theory containing a color-octet technipion, usually denoted by $P^{0'}_{8}$, will give rise to an enhancement of $t \bar t$ production at the Tevatron, LHC and SSC, via the process $gg \rightarrow P^{0'}_{8} \rightarrow t \bar t$. The relevant cross-sections are computed taking into account the large lower bound on the top mass coming from the "top search" experiments at LEP and CDF. At the LHC and SSC, the signal is found to be comparable to the QCD background, making the process quite accesible.