175 research outputs found
Le colporteur, [electronic resource] : histoire morale et critique, par M. de Chevrier.
No full textThe imprint is false; probably printed on the continent.In this 228p. edition the word "an" in the imprint is not capitalized and the double rule begins under the "h" of "chez".Weller = BrusselsMartin, Mylne & Frautschi,Electronic reproduction.English Short Title Catalog,Reproduction of original from "Department of Special Collections, Kenneth Spencer Research Library, University of Kansas"
Search for charged Higgs bosons in e+e- collisions at energies up to sqrt(s) = 209GeV
No full textA search for charged Higgs bosons produced in pairs is performed with data collected at centre-of-mass energies ranging from 189 to 209 GeV by ALEPH at LEP, corresponding to a total luminosity of 629 invpb. The three final states taunutaunu, taunucs and cscs are considered. No evidence for a signal is found and lower limits are set on the mass M_H+ as a function of the branching fraction B(H to taunu). In the framework of a two-Higgs-doublet model, and assuming B(H+ to taunu + B(H+ to cs) = 1 charged Higgs bosons with masses below 79.3 Gev/c2 are excluded at 95% confidence level independently of the branching ratios
Statistical Bootstrap Model of Hadrons
No full textThe hadron is considered to be a compound with two or more constituents circulating freely in a box of radius ≈10^-13 cm. The density of hadron levels, ρ (m), is estimated from the number of states in the box (statistical condition) and is also required to be consistent with the spectrum of constituents, which are assumed to be the hadrons themselves (bootstrap condition). This type of model was first considered by Hagedorn, who obtained a solution of form ρ m∼cm^ae^(bm) with a=-5/2 which satisfied the bootstrap condition asymptotically to within a power of m. We obtain a solution with a<-5/2 which satisfies the bootstrap condition exactly in the high-mass limit. The constituents in the box are distributed with probability P(n)=(ln2)^(n-1)/(n-1)!; i.e., an average high-mass resonance decays (in the first generation of its decay chain) to two hadrons (69% probability) or three (24% probability). We also review briefly the thermodynamic applications of this model to high-energy scattering and astrophysics
Finite Element Simulations of Shape Memory Alloy Actuators in Adaptive Structures
No full textShape memory alloys possess an inherent actuation capability that makes them attractive as actuators in adaptive structures, especially in applications in which their large strains, high specific work output and potential for structural integration are beneficial. However, the requisite extensive physical testing has slowed development of potential applications and highlighted the need for a simulation tool for feasibility studies. In this study, such a tool has been developed by implementing the Müller-Achenbach-Seelecke shape memory alloy model into a commercial finite element code. The material model is described with particular emphasis on its ability to predict actuatoric performance and suitability for use in the context of a displacement-based finite element framework. The interaction between the material model and the solution algorithm for the global finite element equations is thoroughly investigated with respect to the effect of solution parameters on convergence, computational cost and accuracy. Finally, simulations of several flexible structures actuated by shape memory alloys are presented as examples of the potential of the implementation to analyze practical applications. The implementation represents a versatile and novel tool for the simulation of adaptive structural components using shape memory alloy actuators
Ericson fluctuations in the systems in the energy range 2 to 3.5 GeV
No full textExisting data on pi /sup +or-/p total cross-sections and 180 degrees elastic differential cross-sections in the energy range 2<E/sub cm /<3.5 GeV are used to estimate the fluctuating differential cross- section within the statistical models of Ericson and Frautschi. A mass spectrum of the form rho (m)=a(m/m/sub 0/)/sup b/exp(cm) describes correctly the fluctuations observed in total cross-sections and in 180 degrees elastic differential cross-sections. The mass spectrum is found to be denser for pi /sup -/p than for pi /sup +/p. (23 refs)
The neutral pion yield in the statistical model for e +e - annihilation
No full textEngels J, Fabricius K, Schilling K. The neutral pion yield in the statistical model for e +e - annihilation. Physics Letters, B. 1974;53(1):65-66.We consider the decay of neutral fireballs with mass M into [pi] +, -,0 and derive the first two leading terms of the average multiplicities as a function of M. We discuss the implication of this result for a statistical bootstrap description of e +e - annihilation into hadrons
Bulk radiation damage in silicon detectors and implications for LHC experiments
No full textBulk radiation damage to high resistivity n-type silicon detectors was studied with incident pi(+) (190 MeV) and protons (500, 647 or 800 MeV). Silicon bulk damage constants were extracted based on proton fluences, phi up to similar to 8x10(13) cm(-2) and for pi(+) fluences up to similar to 3x10(13) cm(-2). Although the measured damage constants for pi(+) and for proton irradiations were different, a simple empirical relationship was proposed to relate the pi(+) and proton radiation damage data. In addition: (a) Activation time constants for reverse annealing were determined at four temperatures between 0 degrees C and 50 degrees C. (b) 8 silicon detectors were exposed to a second proton fluence of similar to 3x10(13) cm(-2). The resulting changes in the effective dopant concentration, N-eff, were consistent with a model where the bulk radiation effects were purely additive. (c) Following reverse annealing the bulk radiation damage to high resistivity n-type silicon detectors was consistent with the simple functional form: N-eff(phi)=N-eff(0)e(-c phi)-(g(c)+g(y))phi, with c, g(c) and g(y) damage coefficients measured for pi(+) and proton radiation. The measured damage coefficients were used to provide predictions for the depletion voltage for the innermost pixel and silicon strip layers in the large detectors at the LHC
Implications of the statistical bootstrap model for cosmology and galaxy formation
No full textThe statistical bootstrap model suggests that the hadron level density is sigma (m) approximately Cm/sup -3/ exp(m/T/sub h/). With a spectrum of this type, massive hadron resonances will predominate in the early stages of the big bang. and the universe will evolve out of equilibrium. The decay chains of these resonances may be so lengthy that the hadron era is prolonged far past its conventional end. The subsequent radiation era will be considerably foreshortened. and will have major consequences. (38 refs)
Effective temperature of resonance decay in the statistical bootstrap model
No full textThe energy spectrum of pions emitted in the decay of a heavy resonance with mass m is calculated in the statistical bootstrap model, and compared with the Boltzmann form p/sup 2/exp(-E/kT/sub eff/) to determine an effective temperature. The calculated T/sub eff/ is near Hagedorn's limiting temperature T/sub 0/, but lies (15/25)% higher at low E and varies somewhat with energy as E approaches its kinematic limit m/2. These deviations from T/sub 0/ result from working with phase space rather than the canonical ensemble, and from following through the full decay chain of the heavy resonance. Consequences for shape of the transverse-momentum spectrum in inclusive reactions and for the deduction of T/sub 0/ from that spectrum are discussed. (12 refs)
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