20,161 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

    Deep-Elastic pp Scattering at LHC from Low-x Gluons

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    Deep-elastic pp scattering at c.m. energy 14 TeV at LHC in the momentum transfer range 4 GeV*2 < |t| < 10 GeV*2 is planned to be measured by the TOTEM group. We study this process in a model where the deep-elastic scattering is due to a single hard collision of a valence quark from one proton with a valence quark from the other proton. The hard collision originates from the low-x gluon cloud around one valence quark interacting with that of the other. The low-x gluon cloud can be identified as color glass condensate and has size ~0.3 F. Our prediction is that pp differential cross section in the large |t| region decreases smoothly as momentum transfer increases. This is in contrast to the prediction of pp differential cross section with visible oscillations and smaller cross sections by a large number of other models.Comment: 10 pages, including 4 figure

    High Energy pp Elastic Scattering in Condensate Enclosed Chiral Bag Model and TOTEM Elastic Measurements at LHC at 7 TeV

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    We study high energy pp\small{\rm{pp}} and pˉp\small{\rm{\bar {p}p}} elastic scattering in the TeV region based on an effective field theory model of the proton. We phenomenologically investigate the main processes underlying elastic scattering and quantitatively describe the measured elastic dσ\small{\sigma}/dt at energies 7.0 TeV (LHC pp\small{\rm{pp}}), 1.96 TeV (Tevatron pˉp\small{\rm{\bar {p}p}}), and 0.630 TeV (SPS pˉp\small{\rm{\bar {p}p}}). Finally, we give our prediction for pp\small{\rm{pp}} elastic dσ\small{\sigma}/dt at 14 TeV that will be measured by the TOTEM Collaboration.Comment: Presented at EDS Blois 2013 (arXiv:1309.5705

    Subnanosecond magnetization reversal of magnetic nanoparticle driven by chirp microwave field pulse

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    We investigate the magnetization reversal of single-domain magnetic nanoparticle driven by linear down-chirp microwave magnetic field pulse. Numerical simulations based on the Landau-Lifshitz-Gilbert equation reveal that solely down-chirp pulse is capable of inducing subnanosecond magnetization reversal. With a certain range of initial frequency and chirp rate, the required field amplitude is much smaller than that of constant-frequency microwave field. The fast reversal is because the down-chirp microwave field acts as an energy source and sink for the magnetic particle before and after crossing over the energy barrier, respectively. Applying a spin-polarized current additively to the system further reduces the microwave field amplitude. Our findings provide a new way to realize low-cost and fast magnetization reversal

    Evaluating Response to High-Dose 13.3 mg/24 h Rivastigmine Patch in Patients with Severe Alzheimer's Disease

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    AIMS: To identify factors predicting improvement/stabilization on the Alzheimer's Disease Cooperative Study-Clinical Global Impression of Change (ADCS-CGIC) and investigate whether early treatment responses can predict long-term outcomes, during a trial of 13.3 mg/24 h versus 4.6 mg/24 h rivastigmine patch in patients with severe Alzheimer's disease (AD). METHODS: Logistic regression was used to relate Week 24 ADCS-CGIC score to potential baseline predictors. Additional analyses based on receiver-operating characteristic curves were performed using Week 8/16 ADCS-CGIC scores to predict response (13.3 mg/24 h patch) at Week 24. ADCS-CGIC score of (1) 1-3 = "improvement," (2) 1-4 = "improvement or no change". RESULTS: "Treatment" (13.3 mg/24 h patch) and increased age were significant predictors of "improvement" (P = 0.01 and P = 0.003, respectively), and "treatment" (P = 0.001), increased age (P = 0.002), and prior AD treatment (P = 0.03) for "improvement or no change". At Week 8 and 16, ADCS-CGIC scores of 4 and 5 were optimal thresholds in predicting "improvement," and "improvement or no change," respectively, at Week 24. CONCLUSIONS: A significant therapeutic effect of high-dose rivastigmine patch on ADCS-CGIC response was observed. The 13.3 mg/24 h patch was identified as a predictor of "improvement" or "improvement or no change". Patients with minimal worsening/improvement/no change after treatment initiation may be more likely to respond following long-term therapy

    p p Elastic Scattering at LHC and Nucleon Structure

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    High energy elastic ppp p scattering at the Large Hadron Collider (LHC) at c.m. energy 14 TeV is predicted using the asymptotic behavior of σtot(s)\sigma_{tot}(s) and ρ(s)\rho(s) known from dispersion relation calculations and the measured elastic pˉp\bar p p differential cross section at s=546GeV\sqrt{s} = 546 {\rm GeV}. The effective field theory model underlying the phenomenological analysis describes the nucleon as having an outer cloud of quark-antiquark condensed ground state, an inner core of topological baryonic charge of radius 0.44F\simeq 0.44F and a still smaller valence quark-bag of radius 0.1F\lesssim 0.1 {\rm F}. The LHC experiment TOTEM (Total and Elastic Measurement), if carried out with sufficient precision from t=0|t| = 0 to t>10GeV2|t| > 10 {\rm GeV^2}, will be able to test this structure of the nucleon.Comment: 13 pages, 6 figures, to be published in the Modern Physics Letters
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