4,212 research outputs found

    pp Elastic Scattering at LHC in a Nucleon-Structure Model

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    We predict pp elastic differential cross sections at LHC at c.m. energy 14 TeV and momentum transfer range |t| = 0 - 10 GeV*2 in a nucleon-structure model. In this model, the nucleon has an outer cloud of quark-antiquark condensed ground state, an inner shell of topological baryonic charge (r ~ 0.44F) probed by the vector meson omega, and a central quark-bag (r ~ 0.2F) containing valence quarks. We also predict elastic differential cross section in the Coulomb-hadronic interference region. Large |t| elastic scattering in this model arises from valence quark-quark scattering, which is taken to be due to the hard-pomeron (BFKL pomeron with next to leading order corrections). We present results of taking into account multiple hard-pomeron exchanges, i.e. unitarity corrections. Finally, we compare our prediction of pp elastic differential cross section at LHC with the predictions of various other models. Precise measurement of pp elastic differential cross section at LHC by the TOTEM group in the |t| region 0 - 5 GeV*2 will be able to distinguish between these models.Comment: To be published in the Proceedings of the 12th International Conference on Elastic and Diffractive Scattering, DESY, Hamburg. Presented by M. M. Islam, May 200

    Modeling of nanoparticle coatings for medical applications

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    Abstract Gold nanoparticles (AuNPs) have been shown to possess properties beneficial for the treatment of cancerous tumors by acting as radiosensitizers for both photon and ion radiation. Blood circulation time is usually increased by coating the AuNPs with poly(ethylene glycol) (PEG) ligands. The effectiveness of the PEG coating, however, depends on both the ligand surface density and length of the PEG molecules, making it important to understand the structure of the coating. In this paper the thickness, ligand surface density, and density of the PEG coating is studied with classical molecular dynamics using the software package MBN Explorer. AuNPs consisting of 135 atoms (approximately 1.4 nm diameter) in a water medium have been studied with the number of PEG ligands varying between 32 and 60. We find that the thickness of the coating is only weakly dependent on the surface ligand density and that the degree of water penetration is increased when there is a smaller number of attached ligands

    An Extinction Map and Color Magnitude Diagram for the Globular Cluster NGC 3201

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    Differential EV−IE_{V-I} variations of up to ∼0.2\sim 0.2 mag on a scale of arcminutes across NGC 3201 are presented in the form of an extinction map. This map, created by calculating average EV−IE_{V-I} values for stars in small subregions of the field with respect to a fiducial region, greatly improves the appearance of the CMD of the cluster. We describe how we implemented this technique in detail with our data for NGC 3201. A comparison between our map and that of the same region extracted from the COBE/DIRBE reddening maps published by Schlegel, Finkbeiner, & Davis (1998) (SFD) displays larger-scale similarities between the two maps as well as smaller-scale features which show up in our map but not in the SFD map. Several methods of determining an EV−IE_{V-I} zeropoint to add to our differential extinction map are presented. Isochrone fitting proved to be the most successful one, but it produces an average EV−IE_{V-I} for the cluster which is smaller than previously published values by ∼1.5σ\sim 1.5\sigma. Finally, our results seem to support the statement by Arce & Goodman (1999) that the SFD maps overestimate the reddening in regions of high extinction.Comment: 19 pages, 12 figures, 1 table, accepted for publication in AJ (March 2001). Full resolution version may be obtained at http://www.astro.lsa.umich.edu/users/kaspar/html/ngc3201.pdf (PDF) and at http://www.astro.lsa.umich.edu/users/kaspar/html/ngc3201.ps.gz (PS

    Statistical analysis for thermometric sensors test program final report

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    Statistical models for regression analysis of thermometric sensor

    Measurement of the dependence of the light yields of linear alkylbenzene-based and EJ-301 scintillators on electron energy

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    An experimental test of the electron energy scale linearities of SNO+ and EJ-301 scintillators was carried out using a Compton spectrometer with electrons in the energy range 0.09-3 MeV. The linearity of the apparatus was explicitly demonstrated. It was found that the response of both types of scintillators with respect to electrons becomes non-linear below ~0.4 MeV. An explanation is given in terms of Cherenkov light absorption and re-emission by the scintillators.Comment: 8 pages, 7 figure
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