43 research outputs found

    Higgs-photon associated production at eeˉe\bar{e} colliders

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    We present complete analytical expressions for the amplitudes of the process eeˉHγe\bar{e}\rightarrow H\gamma. The calculation is performed using nonlinear gauges, which significantly simplifies both the actual analytical calculation and the check of its gauge invariance. After comparing our results with a previous numerical calculation, we extend the range of Higgs masses and center of mass energies to those appropriate to LEP 200 and a future linear collider.Comment: To appear in PRD. 18 pages latex, uses REVTEX; 5 postscript figure

    Photons, neutrinos and optical activity

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    We compute the one-loop helicity amplitudes for low-energy νγνγ\nu\gamma\to\nu\gamma scattering and its crossed channels in the standard model with massless neutrinos. In the center of mass, with s=2ω2me\sqrt{s} = 2\omega\ll 2m_e, the cross sections for these 222\to 2 channels grow roughly as ω6\omega^6. The scattered photons in the elastic channel are circularly polarized and the net value of the polarization is non-zero. We also present a discussion of the optical activity of a sea of neutrinos and estimate the values of its index of refraction and rotary power.Comment: 9 pages, ReVTeX4, 6 figures include

    High energy photon-neutrino elastic scattering

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    The one-loop helicity amplitudes for the elastic scattering process γνγν\gamma\nu\to\gamma\nu in the Standard Model are computed at high center of mass energies. A general decomposition of the amplitudes is utilized to investigate the validity of some of the key features of our results. In the center of mass, where s=2ω\sqrt{s} = 2\omega, the cross section grows roughly as ω6\omega^6 to near the threshold for WW-boson production, s=mW\sqrt{s} = m_W. Although suppressed at low energies, we find that the elastic cross section exceeds the cross section for γνγγν\gamma\nu\to\gamma\gamma\nu when s>13\sqrt{s}>13 GeV. We demonstrate that the scattered photons are circularly polarized and the net value of the polarization is non-zero. Astrophysical implications of high energy photon-neutrino scattering are discussed.Comment: 9 pages, 7 figures, RevTeX

    Analysis of Intelligent Classifiers and Enhancing the Detection Accuracy for Intrusion Detection System

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    In this paper we discuss and analyze some of the intelligent classifiers which allows for automatic detection and classification of networks attacks for any intrusion detection system. We will proceed initially with their analysis using the WEKA software to work with the classifiers on a well-known IDS (Intrusion Detection Systems) dataset like NSL-KDD dataset. The NSL-KDD dataset of network attacks was created in a military network by MIT Lincoln Labs. Then we will discuss and experiment some of the hybrid AI (Artificial Intelligence) classifiers that can be used for IDS, and finally we developed a Java software with three most efficient classifiers and compared it with other options. The outputs would show the detection accuracy and efficiency of the single and combined classifiers used

    Production of ZZ Boson Pairs at Photon Linear Colliders

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    The ZZZZ pair production rate in high energy γγ\gamma \gamma collisions is evaluated with photons from laser backscattering. We find that searching for the Standard Model Higgs boson with a mass up to, or slightly larger than, 400 GeV via the ZZZZ final state is possible via photon fusion with backscattered laser photons at a linear e+ee^+e^- collider with energies in the range 600 GeV <se+e<< \sqrt{s_{e^+e^-}} < 1000 GeV.Comment: 18 pages in REVTEX, Figures available upon request, DOE-ER40757-024,CPP-93-24 and FSU-HEP-93080

    Advanced Television Research Program

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    Contains reports on ten research projects.National Science Foundation Grant MIP 87-14969National Science Foundation FellowshipAdvanced Television Research ProgramAT&T Bell Laboratories Doctoral Support ProgramKodak FellowshipU.S. Air Force - Electronic Systems Division Contract F1 9628-89-K-004

    Advanced Television and Signal Processing Program

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    Contains an introduction and reports on fifteen research projects.Advanced Television Research ProgramAdams-Russell Electronics, Inc.National Science Foundation Fellowship Grant MIP 87-14969National Science Foundation FellowshipU.S. Navy - Office of Naval Research Grant N00014-89-J-1489U.S. Air Force - Electronic Systems Division Contract F1 9628-89-K-004

    Form Factors and QCD in Spacelike and Timelike Region

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    We analyze the basic hard exclusive processes: \pi\gamma*\gamma - transition, pion and nucleon electromagnetic form factors, and discuss the analytic continuation of QCD formulas from the spacelike q^2<0 to the timelike region q^2 >0 of the relevant momentum transfers. We describe the construction of the timelike version of the coupling constant \alpha_s. We show that due to the analytic continuation of the collinear logarithms each eigenfunction of the evolution equation acqiures a phase factor and investigate the resulting interference effects which are shown to be very small. We found no sources for the K-factor-type enhancements in the perturbative QCD contribution to the hadronic form factors. To study the soft part of the pion electromagnetic form factor, we use a QCD sum rule inspired model and show that there are non-canceling Sudakov double logarithms which result in a K-factor-type enhancement in the timelike region.Comment: 12 pages, LaTeX; a few typos corrected, references adde

    Digital Signal Processing

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    Contains an introduction and reports on fifteen research projects.National Science Foundation FellowshipU.S. Navy - Office of Naval Research (Contract N00014-81-K-0742)National Science Foundation (Grant ECS 84-07285)Sanders Associates, Inc.U.S. Air Force - Office of Scientific Research (Contract F19628-85-K-0028)AT&T Bell Laboratories Doctoral Support ProgramCanada, Bell Northern Research ScholarshipCanada, Fonds pour la Formation de Chercheurs et /'Aide a la Recherche Postgraduate FellowshipCanada, Natural Science and Engineering Research Council Postgraduate FellowshipAmoco Foundation FellowshipFannie and John Hertz Foundation Fellowshi

    Natural disturbance impacts on trade-offs and co-benefits of forest biodiversity and carbon

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    With accelerating environmental change, understanding forest disturbance impacts on trade-offs between biodiversity and carbon dynamics is of high socio-economic importance. Most studies, however, have assessed immediate or short-term effects of disturbance, while long-term impacts remain poorly understood. Using a tree-ring-based approach, we analysed the effect of 250 years of disturbances on present-day biodiversity indicators and carbon dynamics in primary forests. Disturbance legacies spanning centuries shaped contemporary forest co-benefits and trade-offs, with contrasting, local-scale effects. Disturbances enhanced carbon sequestration, reaching maximum rates within a comparatively narrow post-disturbance window (up to 50 years). Concurrently, disturbance diminished aboveground carbon storage, which gradually returned to peak levels over centuries. Temporal patterns in biodiversity potential were bimodal; the first maximum coincided with the short-term post-disturbance carbon sequestration peak, and the second occurred during periods of maximum carbon storage in complex old-growth forest. Despite fluctuating local-scale trade-offs, forest biodiversity and carbon storage remained stable across the broader study region, and our data support a positive relationship between carbon stocks and biodiversity potential. These findings underscore the interdependencies of forest processes, and highlight the necessity of large-scale conservation programmes to effectively promote both biodiversity and long-term carbon storage, particularly given the accelerating global biodiversity and climate crises
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