4,778 research outputs found
A linear moose model with pairs of degenerate gauge boson triplets
The possibility of the existence of a strongly interacting electroweak
symmetry breaking sector, as opposed to the weakly interacting light Higgs of
the Standard Model, is not yet ruled out by experiments. In this paper we make
an extensive study of a deconstructed model (or ``moose'' model) providing a
possible effective description of such a strong symmetry breaking sector, and
show its compatibility with experimental data for a wide portion of the model
parameters space. The model is a direct generalization of the previously
proposed D-BESS model.Comment: Latex file, 17 pages, 2 figures, published versio
Analysis of Narrow s-channel Resonances at Lepton Colliders
The procedures for studying a single narrow s-channel resonance or nearly
degenerate resonances at a lepton collider, especially a muon collider, are
discussed. In particular, we examine four methods for determining the
parameters of a narrow s-channel resonance: scanning the resonance, measuring
the convoluted cross section, measuring the Breit-Wigner area, and sitting on
the resonance while varying the beam energy resolution. This latter procedure
is new and appears to be potentially very powerful. Our focus is on computing
the errors in resonance parameters resulting from uncertainty in the beam
energy spread. Means for minimizing these errors are discussed. The discussion
is applied to the examples of a light SM-Higgs, of the lightest pseudogoldstone
boson of strong electroweak breaking, and of the two spin-1 resonances of the
Degenerate BESS model (assuming that the beam energy spread is less than their
mass splitting). We also examine the most effective procedures for nearly
degenerate resonances, and apply these to the case of Degenerate BESS
resonances with mass splitting of order the beam energy spread.Comment: 63 pages, 16 figure
A Strong Electroweak Sector at Future mu^+ mu^- Colliders
We discuss the prospects for detecting at a muon collider the massive new
vector resonances V and light pseudo-Nambu-Goldstone bosons P of a typical
strongly interacting electroweak sector (as represented by the BESS model).
Expected sensitivities to V's at a high energy collider are evaluated and the
excellent prospects for discovering P's via scanning at a low energy collider
are delineated.Comment: LaTeX, uses aipproc.cls, aipproc.sty, 10 pages, 6 figures, presented
at the Workshop on Physics at the First Muon Collider, Fermilab, November
1997, to appear in the Proceedings, some references added and minor changes
in the tex
The Lightest Pseudo-Goldstone Boson at Future e+e- Colliders
In a class of models of dynamical symmetry breaking not ruled out by the
available data, the lightest neutral pseudo-Nambu-Goldstone boson P0 contains
only down-type techniquarks and charged technileptons. Its mass scale is
naturally determined by the b-quark and therefore it is likely to be light. As
the presence of pseudo-Nambu-Goldstone bosons in models of dynamical symmetry
breaking is a quite general feature, the search of the P0 at colliders is an
interesting opportunity of putting limits on or discovering a dynamical
electroweak symmetry breaking scenario. In this note we discuss the prospects
for discovering and studying the P0 at future e+e- and gamma-gamma colliders.Comment: 15 pages, 8 figures, LaTeX (epsfig), Proceedings of the Second
ECFA/DESY Study on Physics Studies for a Future Linear Collide
Indirect sensitivity to ZâČs in high-energy e+eâ collisions: standard vs. composite study
We compare the phenomenology of two models, the so-called âminimal Z'â and an effective model an SM-like Higgs is realised as a composite state of a new strong interaction, at a multi-TeV linear collider in the hypothesis that the new physics is at a scale beyond the direct reach of the machine
A New Technique for Determining the Properties of a Narrow -channel Resonance at a Muon Collider
We explore an alternative to the usual procedure of scanning for determining
the properties of a narrow -channel resonance. By varying the beam energy
resolution while sitting on the resonance peak, the width and branching ratios
of the resonance can be determined. The statistical accuracy achieved is
superior to that of the usual scan procedure in the case of a light SM-like
Higgs boson with \mh>130\gev or for the lightest pseudogoldstone boson of a
strong electroweak breaking model if \mpzero>150\gev.Comment: 4 pages, 1 figur
Integration of biocontrol agents and food-grade additives for enhancing protection of stored apples from Penicillium expansum.
Forty-nine compounds currently used as additives in foods were tested in combination with three biocontrol agents, the yeasts Rhodotorula glutinis, Cryptococcus laurentii, and the yeastlike fungus Aureobasidium pullulans, to increase their antagonistic activity against Penicillium expansum, the causal agent of blue mold on apples. Twelve additives dramatically improved the antagonistic activity of one or more of the tested biocontrol agents. In a two-way factorial experiment with these selected additives the percentage of P. expansum rots on apples was significantly influenced by the antagonist and the additive as well as by their interaction. The combination of the biocontrol agents and some additives resulted in a significantly higher activity with respect to the single treatments applied separately, producing additive or synergistic effects. Some of the selected additives combined with a low yeast concentration (106 cells per ml) had comparable or higher efficacy than the biocontrol agents applied alone at a 100-fold higher concentration (10(8) cells per ml). Some organic and inorganic calcium salts, natural gums, and some antioxidants displayed the best results. In general, the effect of each additive was specific to the biocontrol isolate used in the experiments. Possible mechanisms involved in the activity of these beneficial additives and their potential application in effective formulations of postharvest biofungicides are discussed
Modified spontaneous symmetry breaking pattern by brane-bulk interaction terms
We show how translational invariance can be broken by the vacuum that drives
the spontaneous symmetry breaking of extra-dimensional extensions of the
Standard Model, when delta-like interactions between brane and bulk scalar
fields are present. We explicitly build some examples of vacuum configurations,
which induce the spontaneous symmetry breaking, and have non trivial profile in
the extra coordinate.Comment: 13 pages, two figure
A Lower Bound on List Size for List Decoding
A q-ary error-correcting code C â {1,2,...,q}n is said to be list decodable to radius Ï with list size L if every Hamming ball of radius Ï contains at most L codewords of C. We prove that in order for a q -ary code to be list-decodable up to radius (1-1/q)(1- Δ)n, we must have L = Ω(1/ Δ2) . Specifically, we prove that there exists a constant cq > 0 and a function fq such that for small enough Δ > 0, if C is list-decodable to radius (1-1/q)(1- Δ)n with list size cq/ Δ2, then C has at most fq( Δ) codewords, independent of n . This result is asymptotically tight (treating q as a constant), since such codes with an exponential (in n ) number of codewords are known for list size L = O(1/ Δ2). A result similar to ours is implicit in Blinovsky ( Problems of Information Transmission, 1986) for the binary (q=2) case. Our proof is simpler and works for all alphabet sizes, and provides more intuition for why the lower bound arises.Engineering and Applied Science
W' production at the LHC in the 4-site Higgsless model
We study the phenomenology of the 4-site Higgsless model, based on the
gauge symmetry, at present
colliders. The model predicts the existence of two neutral and four charged
extra gauge bosons, Z1,Z2,W1,W2. In this paper, we focus on the charged gauge
sector. We first derive limits on W1,W2-boson masses and couplings to SM
fermions from direct searches at the Tevatron. We then estimate at the 7 TeV
LHC the exclusion limits with the actual L=1 fb-1 and the discovery potential
with the expected L=10 fb-1. In contrast to the minimal (or 3-site) Higgsless
model which predicts almost fermiophobic extra gauge bosons, the
next-to-minimal (or 4-site) Higgsless model recovers sizeable W1,W2-boson
couplings to ordinary matter, expressing the non-fermiophobic multiresonance
inner nature of extra-dimensional theories. Owing to this feature, we find that
in one year from now the new heavy gauge bosons, W1 and W2, could be discovered
in the final state with an electron and large missing transverse energy at the
7 TeV LHC for W1,W2-boson masses in the TeV region, depending on model
parameters.Comment: 28 pages, references adde
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