Search results for "scattering theory"
showing 10 items of 317 documents
Collision Theory for Two- and Three-Particle Systems Interacting via Short-Range and Coulomb Forces
1996
In two- and three-particle reactions with light nuclei, a rich body of precise experimental data exists in which both projectile and target and/or the fragments occurring in the final state are charged. In order to make optimal use of these data for extracting physically interesting information about the nuclear interactions, the effects of the Coulomb force must be separated out in a reliable manner. For this purpose the mastering of the intricacies of charged-particle scattering theory is of vital importance.
Direct method for calculating temperature-dependent transport properties
2015
We show how temperature-induced disorder can be combined in a direct way with first-principles scattering theory to study diffusive transport in real materials. Excellent (good) agreement with experiment is found for the resistivity of Cu, Pd, Pt (and Fe) when lattice (and spin) disorder are calculated from first principles. For Fe, the agreement with experiment is limited by how well the magnetization (of itinerant ferromagnets) can be calculated as a function of temperature. By introducing a simple Debye-like model of spin disorder parameterized to reproduce the experimental magnetization, the temperature dependence of the average resistivity, the anisotropic magnetoresistance and the spi…
Inelastic neutron scattering due to acoustic vibrations confined in nanoparticles: theory and experiment
2008
The inelastic scattering of neutrons by nanoparticles due to acoustic vibrational modes (energy below 10 meV) confined in nanoparticles is calculated using the Zemach-Glauber formalism. Such vibrational modes are commonly observed by light scattering techniques (Brillouin or low-frequency Raman scattering). We also report high resolution inelastic neutron scattering measurements for anatase TiO2 nanoparticles in a loose powder. Factors enabling the observation of such vibrations are discussed. These include a narrow nanoparticle size distribution which minimizes inhomogeneous broadening of the spectrum and the presence of hydrogen atoms oscillating with the nanoparticle surfaces which enhan…
Search for a heavy Higgs boson decaying into a Z boson and another heavy Higgs boson in the ℓℓbb final state in pp collisions at s=13 TeV with the AT…
2018
A search for a heavy neutral Higgs boson, A, decaying into a Z boson and another heavy Higgs boson, H, is performed using a data sample corresponding to an integrated luminosity of 36.1 fb(-1) from ...
Limits on anomalous trilinear gauge boson couplings from WW, WZ and Wγ production in pp¯ collisions at s=1.96 TeV
2012
We present searches for the anomalous γWW and ZWW trilinear gauge boson couplings from WW and WZ production using lepton plus dijet final states and a combination with results from Wγ, WW, and WZ production with leptonic final states. The analyzed data correspond to up to 8.6fb -1 of integrated luminosity collected by the D0 detector in pp- collisions at s=1.96TeV. We set the most stringent limits at a hadron collider to date assuming two different relations between the anomalous coupling parameters δκ γ, λ, and δg1Z for a cutoff energy scale Λ=2TeV. The combined 68% C.L. limits are -0.057lδκ γl0.154, -0.015lλl0.028, and -0.008lδg1Zl0.054 for the LEP parameterization, and -0.007lδκl0.081 an…
Search for flavor changing neutral currents in decays of top quarks
2011
We present a search for flavor changing neutral currents in decays of top quarks. The analysis is based on a search for ttbar -> l'null + jets (l, l' = e, mu) final states using 4.1 fb^-1 of integrated luminosity of ppbar collisions at sqrt(s) = 1.96 TeV. We extract limits on the branching ratio B(t -> Zq) (q = u, c quarks), assuming anomalous tuZ or tcZ couplings. We do not observe any sign of such anomalous coupling and set a limit of B < 3.2% at 95% C.L.
Multiple scattering theory for non-local and multichannel potentials.
2012
International audience; Methodological advances in multiple scattering theory (MST) in both wave and Green's function versions are reported for the calculation of electronic ground and excited state properties of condensed matter systems with an emphasis on core-level photoemission and absorption spectra. Full-potential MST is reviewed and extended to non-local potentials. Multichannel MST is reformulated in terms of the multichannel density matrix whereby strong electron correlation of atomic multiplet type can be accounted for in both ground and excited states.
Role of Levinson’s theorem in neutron-deuteron quartetS-wave scattering
1990
The real part of the phase shift for elastic neutron-deuteron scattering in the quartet {ital S} wave channel, as calculated with the exact three-body theory, assumes at threshold the value {pi} if normalized to zero at infinity; that is, it does not comply with the expectations raised by a naive application of Levinson's theorem since no bound state exists in this channel. A description of this situation on an equivalent two-body level via a potential, constructed by means of the Marchenko inverse scattering theory, necessitates the introduction of a fictitious bound state. This predominantly attractive, equivalent local potential can be related via supersymmetry to a strictly phase equiva…
Proton-Hydrogen Charge Exchange and Elastic Scattering in the Faddeev Approach
2000
Results of the application of Faddeev-type integral equations to proton-hydrogen collisions are reported. The approach, realized in the impact parameter representation, incorporates the exact two-particle off-shell Coulomb T-matrices in all ‘triangle’ contributions to the effective potentials. Calculatedtotal and differential electron-transfer as well as differential elastic scattering cross sections show very good agreement with experiment, over a wide range of incident energies.
Scattering Matrix and Observables in Scattering and Decays
2013
As an interlude in the analysis of canonical field quantization, this section describes important concepts of scattering theory for Lorentz covariant quantum field theories that will be needed for the calculation of observables such as scattering cross sections and decay probabilities.