Probing exotic leptons through oblique parameters
TL;DR: In this paper, it was shown that the oblique electroweak parameter S receives a small positive contribution when sterile neutrinos or vector doublet leptons mix with their sequential counterparts.
About: This article is published in Physics Letters B.The article was published on 1992-12-17 and is currently open access. It has received 1 citations till now. The article focuses on the topics: Electroweak interaction & Sterile neutrino.
Summary (1 min read)
Contents
- The solid state 13C-NMR spectra of some carbides Daniel T. Haworth Department of Chemistry, Marquette University, Milwaukee, WI Charles A. Wilkie Department of Chemistry, Marquette University, Milwaukee, WI The utility of NMR spectroscopy to the study of liquids or solids dissloved in liquids is well known.
- This technique has been used infrequently to studies in the solid state.
- The 13C-NMR of ebony and ivory have been studied by the magic angle technique.
EXPERIMENTAL
- The following carbides were used as received from the supplier: CaC2 (Fischer Scientific), Al4C3 (A. D. MacKay), SiC, B4Si, Mn23C6 (Cerac/Pure, Inc.).
- The 13C-NMR spectra were obtained on a JEOL FX-60 spectrometer operating in the external lock mode.
- TMS was used as an external referency by tube substitution.
- The spectra were integrated by cutting and weighing xerox copies of the spectra.
DISCUSSION
- The different structural types of carbides used in this study were: ionic, CaC2 and Al4C3; interstitial, Mn23C6 and covalent, SiC and B4C.
- Calcium carbide structure consists of discrete Ca 2+ and C22- ions in the lattice structure, whereas AI4C3 has carbon atoms in its structure.
- The high field resonance is in a region where non-aromatic carbons are expected and is assigned as the carbide carbon.
- This indicates a graphite impurity of 3-7% in the CaC2.
- Silicon carbide and diamond have the same structure yet the chemical shift of SiC is about 65 ppm downfield from the diamond carbon resonance.
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TL;DR: The possibility that, by the strong four-Fermi interaction, massive vectorlike fields undergo condensation and break electroweak symmetry is examined and the model becomes almost the same as the standard model at a low energy scale and predicts a heavy Higgs boson.
Abstract: In order to build realistic models in which electroweak symmetry is dynamically broken we should explain the smallness of the Peskin-Takeuchi {ital S} and {ital T} parameters. In accordance with the decoupling theorem, these parameters must be suppressed by SU(2){sub {ital L}}{times}U(1){sub {ital Y}} invariant masses. From this fact we can expect that if fermions with large SU(2){sub {ital L}}{times}U(1){sub {ital Y}} invariant masses undergo condensation and break electroweak symmetry, the {ital S} and {ital T} parameters can be small. It is intersting that not only the {ital S} but also the {ital T} parameter can become small even if there exists a large isospin violation in fermion condensation. In this paper we examine the possibility that, by the strong four-Fermi interaction, massive vectorlike fields undergo condensation and break electroweak symmetry. The model becomes almost the same as the standard model at a low energy scale and predicts a heavy Higgs boson. Moreover, we discuss a model in which the four-Fermi interaction can be induced by massive gauge boson exchange. In this model, the masses of ordinary matter fermions (quark and lepton) are enhanced.
21 citations
References
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TL;DR: It is shown that an integral {ital S} over the spectral function of spin-1 states of the Higgs sector is constrained by precision weak-interaction measurements.
Abstract: We show that an integral S over the spectral function of spin-1 states of the Higgs sector is constrained by precision weak-interaction measurements. Current data exclude large technicolor models; asymmetry measurements at the CERN ${\mathit{e}}^{+}$${\mathit{e}}^{\mathrm{\ensuremath{-}}}$ collider LEP and the SLAC Linear Collider will soon provide more stringent limits on Higgs-boson strong interactions.
1,541 citations
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290 citations
TL;DR: Effects of physics beyond the standard model on electroweak observables are studied using the Peskin-Takeuchi isospin-conserving, {ital S} and -breaking, and - Breaking, parametrization of new'' quantum loop corrections.
Abstract: Effects of physics beyond the standard model on electroweak observables ares studied using the Peskin-Takeuchi isospin-conserving, S, and -breaking, T, parametrization of ``new'' quantum loop corrections Experimental constraints on S and T are presented Atomic parity-violating experiments are shown to be particularly sensitive to S with existing data giving S=-27\ifmmode\pm\else\textpm\fi{}20\ifmmode\pm\else\textpm\fi{}11 That constraint has important implications for generic technicolor models which predict S\ensuremath{\simeq}01${\mathit{N}}_{\mathit{T}}$${\mathit{N}}_{\mathit{D}}$ (${\mathit{N}}_{\mathit{T}}$ is the number of technicolors, ${\mathit{N}}_{\mathit{D}}$ is the number of technidoublets)
270 citations