10,164 research outputs found

    The alpha-particle in nuclear matter

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    Among the light nuclear clusters the alpha-particle is by far the strongest bound system and therefore expected to play a significant role in the dynamics of nuclei and the phases of nuclear matter. To systematically study the properties of the alpha-particle we have derived an effective four-body equation of the Alt-Grassberger-Sandhas (AGS) type that includes the dominant medium effects, i.e. self energy corrections and Pauli-blocking in a consistent way. The equation is solved utilizing the energy dependent pole expansion for the sub system amplitudes. We find that the Mott transition of an alpha-particle at rest differs from that expected from perturbation theory and occurs at approximately 1/10 of nuclear matter densities.Comment: 9 pages RevTex file, 1 figure, submitted to Phys. Lett.

    The Perfect Pitch: Car Commercials in the Environment

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    Car commercials, like many advertisements, tempt its viewers with comfort, capability, or safety features, as well as being well‐engineered, affordable, attractive, large or compact sized, or fuel efficient. This study examines the pitches in YouTube car commercial video clips from the 1960s until 2014. We coded a total of 263 total car commercials based on pitch, setting, narrator, decade, and country of origin. The analysis revealed that most car commercials were presented in rural settings and capability was pitched most frequently overall. Fuel efficiency was ranked third overall; however, within urban settings, fuel efficiency had the highest frequency. During the 1990s, there was no presence of commercials alluding to fuel efficiency and instead safety was pitched more frequently compared to other decades. We discuss the other pitches that were found to be significantly different between the settings, narrators, decades, and countries of origin. Over time, pitches in car commercials have changed, perhaps because advertising is influenced by consumer demands, interests, and concerns

    Light clusters in nuclear matter of finite temperature

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    We investigate properties and the distribution of light nuclei (A<4) in symmetric nuclear matter of finite temperature within a microscopic framework. For this purpose we have solved few-body Alt-Grassberger-Sandhas type equations for quasi-nucleons that include self-energy corrections and Pauli blocking in a systematic way. In a statistical model we find a significant influence in the composition of nuclear matter if medium effects are included in the microscopic calculation of nuclei. If multiplicities are frozen out at a certain time (or volume), we expect significant consequences for the formation of light fragments in a heavy ion collision. As a consequence of the systematic inclusion of medium effects the ordering of multiplicities becomes opposite to the law of mass action of ideal components. This is necessary to explain the large abundance of α\alpha-particles in a heavy ion collision that are otherwise largely suppressed in an ideal equilibrium scenario.Comment: 9 pages, 9 figures, epja-style file

    Effective T-odd P-even hadronic interactions from quark models

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    Tests of time reversal symmetry at low and medium energies may be analyzed in the framework of effective hadronic interactions. Here, we consider the quark structure of hadrons to make a connection to the more fundamental degrees of freedom. It turns out that for P-even T-odd interactions hadronic matrix elements evaluated in terms of quark models give rise to factors of 2 to 5. Also, it is possible to relate the strength of the anomalous part of the effective rho-type T-odd P-even tensor coupling to quark structure effects.Comment: 6 pages, 1 figure, RevTe

    Galileo early cruise, including Venus, first Earth, and Gaspra encounters

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    This article documents Deep Space Network (DSN) support for the Galileo cruise to Jupiter. The unique trajectory affords multiple encounters during this cruise phase. Each encounter had or will have unique requirements for data acquisition and DSN support configurations. An overview of the cruise and encounters through the asteroid Gaspra encounter is provided

    Medium corrections in the formation of light charged particles in heavy ion reactions

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    Within a microscopic statistical description of heavy ion collisions, we investigate the effect of the medium on the formation of light clusters. The dominant medium effects are self-energy corrections and Pauli blocking that produce the Mott effect for composite particles and enhanced reaction rates in the collision integrals. Microscopic description of composites in the medium follows the Dyson equation approach combined with the cluster mean-field expansion. The resulting effective few-body problem is solved within a properly modified Alt-Grassberger-Sandhas formalism. The results are incorporated in a Boltzmann-Uehling-Uhlenbeck simulation for heavy ion collisions. The number and spectra of light charged particles emerging from a heavy ion collision changes in a significant manner in effect of the medium modification of production and absorption processes.Comment: 16 pages, 6 figure

    Experimental studies of Strong Electroweak Symmetry Breaking in gauge boson scattering and three gauge boson production

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    If no light Higgs boson exist, the interaction among the gauge bosons becomes strong at high energies (~1TeV). The effects of strong electroweak symmetry breaking (SEWSB) could manifest themselves as anomalous couplings before they give rise to new physical states, thus measurement of all couplings and their possible deviation from Standard Model (SM) values could give valuable information for understanding the true nature of symmetry breaking sector. Here we present a detailed study of the measurement of quartic gauge couplings in weak boson scattering processes and a possibility for same measurement in triple weak boson production. Expected limits on the parameters alpha_4 alpha_5,alpha_6, alpha_7 and alpha_10 in electroweak chiral Lagrangian are given.Comment: talk presented at LCWS05, Stanford, USA, March 200

    Few-Body States in Fermi-Systems and Condensation Phenomena

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    Residual interactions in many particle systems lead to strong correlations. A multitude of spectacular phenomenae in many particle systems are connected to correlation effects in such systems, e.g. pairing, superconductivity, superfluidity, Bose-Einstein condensation etc. Here we focus on few-body bound states in a many-body surrounding.Comment: 10 pages, proceedings 1st Asian-Pacific Few-Body Conference, needs fbssuppl.sty of Few-Body System
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