685544
Strongly Coupled Electroweak Symmetry Breaking: Implications of Models
We discuss the phenomenology of models of dynamical electroweak symmetry breaking which attempt to generate the observed fermion mass spectrum. After briefly describing the variety of and constraints on proposed models, we concentrate on the signatures of colored pseudo-Nambu-Goldstone bosons and resonances at existing and proposed colliders. These particles provide a possibly unique signature: strongly produced resonances associated with electroweak symmetry breaking.
124131390
HOW TO POPULARIZE PARTICLE PHYSICS
This article reviews why efforts to popularize particle physics are so important, offers advice on maximizing the impact and minimizing the effort involved in your own outreach endeavors, and supplies examples of existing effective programs. Readers are urged to make the 2005 World Year of Physics a focus of their current efforts in education and public outreach.
7764904
Limits on noncommuting extended technicolor.
Using precision electroweak data, we put limits on noncommuting extended technicolor models. We conclude that these models are viable only if the ETC interactions are strong. Interestingly, these models predict a pattern of deviations from the standard model which can fit the data significantly better than the standard model does, even after taking into account the extra parameters involved. {copyright} {ital 1996 The American Physical Society.}
18592130
Thinking About Top: Looking Outside The Standard Model ∗
The top quark is by far the heaviest known fermion [1]. In consequence, experiment is just beginning to explore its properties, and some of them may yet prove to be distinctly non-standard. The very size of the top quark’s mass even hints at the possibility of a special role for top in electroweak symmetry breaking. This talk examines the top quark in the context of physics beyond the standard model, and discusses how Run II can help elucidate the true nature of top.
396910
Coloron Phenomenology
A flavor-universal extension of the strong interactions was recently proposed in response to the apparent excess of high-ET jets in the inclusive jet spectrum measured at the Tevatron. This paper studies the color octet of massive gauge bosons (‘colorons’) that is present in the low-energy spectrum of the model’s Higgs phase. Constraints from searches for new particles decaying to dijets and from measurements of the weak-interaction ρ parameter imply that the colorons must have masses greater than 870-1000 GeV. The implications of recent Tevatron data and the prospective input from future experiments are also discussed. e-mail address: simmons@bu.edu A flavor-universal coloron model [1] was recently proposed to explain the apparent excess of high-ET jets in the inclusive jet spectrum measured by CDF [2]. This model is a flavor-universal variant of the coloron model of Hill and Parke [3] which can accommodate the jet excess without contradicting other experimental data. It involves a minimal extension of the standard description of the strong interactions, including the addition of one gauge interaction and a scalar multiplet, but no new fermions. Furthermore, the flavor-universal coloron model of the strong interactions can be grafted onto the standard one-Higgs-doublet model of electroweak physics, yielding a simple, complete, and renormalizable theory. The model serves as a useful baseline with which to compare both the data and other candidate explanations of the jet excess. The latter include such diverse physics as modified parton distribution functions [4], higher-order contributions from gluon resummation [5], phenomenological models of quark substructure [2], new strongly-coupled Z ′ gauge bosons [6], quark resonances [7], non-standard triplegauge vertices [8], and light gluinos [9]. This letter explores the phenomenology of the Higgs phase of the model, in which an octet of strongly-interacting massive gauge bosons (colorons) is present in the low-energy spectrum. Previous work on this model has considered effects on the inclusive jet spectrum [1] and the dijet spectrum and angular distributions [10] in the approximation where coloron exchange is treated as a four-fermion contact interaction. The four-fermion approximation is appropriate for heavy colorons and conveniently allows the model’s effects to be represented in terms of a single parameter: the coefficient of the contact interaction. The present work goes beyond the four-fermion approximation by including propagating colorons of finite width. This allows us to investigate the phenomenology of colorons too light to be welldescribed by contact interactions at Tevatron energies. It also enables us to explore the separate dimensions of the coloron parameter space (mass and mixing angle) independently. We begin by reviewing the main features of the model, in both the Higgs and confining phases. Then, focusing on the Higgs phase, we discuss the effect that the presence of colorons strongly coupled to quarks will have on partonic scattering cross-sections. In section 3, we show what limits may already be placed on the mass and mixing angle of the colorons. Next, we discuss how further experiments can probe the model at higher coloron masses. Our conclusions appear in section 5.
119418089
Phenomenology of a technicolor model with heavy scalar doublet
Abstract Rather than having a light scalar both break SU(2) × U(1) and give mass to the fermions, as in the standard model, it is possible to use technicolor to do the first while a heavy (∼ 10 TeV) scalar does the second. The impact of such a heavy scalar on FCNC in the Kaon and B-meson systems is explored here.
88510456
Experimental study of β -delayed proton decay of Al 23 for nucleosynthesis in novae
The {beta}-delayed {gamma} and proton decay of {sup 23}Al has been studied with an alternative detector setup at the focal plane of the momentum achromat recoil separator MARS at Texas A and M University. We could detect protons down to an energy of 200 keV and determine the corresponding branching ratios. Contrary to results of previous {beta}-decay studies, no strong proton intensity from the decay of the isobaric analog state (IAS) of the {sup 23}Al ground state at E{sub x}=7803 keV in {sup 23}Mg was observed. Instead we assign the observed low-energy group E{sub p,c.m.}=206 keV to the decay from a state that is 16 keV below the IAS. We measured both proton and gamma branches from the decay of this state at E{sub x}=7787 keV in {sup 23}Mg, which is a very rare case in the literature. Combining our data with its measured lifetime, we determine its resonance strength to be {omega}{gamma}=1.4{sub -0.4}{sup +0.5} meV. The value is in agreement with older direct measurements, but disagrees with a recent direct measurement. This state is the most important resonance for the radiative proton capture {sup 22}Na(p,{gamma}){sup 23}Mg in some astrophysical environments, such as novae.
13920958
Development of large area polycrystalline diamond detectors for fast timing application of high-energy heavy-ion beams
We have studied the effects of electrode fabrication and detector capacitance on the time resolution of large area electronic grade polycrystalline chemical vapour deposited diamond sensors that are suitable for time of flight measurements of heavy ions at relativistic velocities. Sensors were prepared both in house, with Al or Au metal contacts, and commercially fabricated with Au/diamond-like carbon contacts. He, Ar and a mixture of Ne and O beams at 16.3, 33.5 and 21-23 MeV/u, respectively were used on these devices whilst arranged in transmission geometry. Signal processing only began over one meter away from the sensors. The present approach, where we have large-area/large capacitance multi-strip detectors with processing electronics at some distance from the target, is compatible with anticipated space limitations in particle- identification and tracking setups at existing and planned nuclear fragmentation facilities. In a systematic study under these conditions, we demonstrate that the time resolution is limited by detector capacitance and energy deposition in the sensors. An intrinsic time resolution σ = (44±5) ps was achieved for a diamond detector of ∼ 14 pF capacitance. We conclude that, once further refinements are made, a large area time of flight detection system using polycrystalline diamond detectors would be able to provide time resolutions better than 40 ps, approaching the requirement for particle-identification in relativistic fragmentation experiments, such as those at the facility for antiproton and ion research, FAIR. © 2012 IOP Publishing Ltd and Sissa Medialab srl.