2,222 research outputs found

    Photon-Photon and Electron-Photon Colliders with Energies Below a TeV

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    We investigate the potential for detecting and studying Higgs bosons in γγ\gamma\gamma and eγe\gamma collisions at future linear colliders with energies below a TeV. Our study incorporates realistic γγ\gamma\gamma spectra based on available laser technology, and NLC and CLIC acceleration techniques. Results include detector simulations. We study the cases of: a) a SM-like Higgs boson based on a devoted low energy machine with see200\sqrt{s_{ee}}\le 200 GeV; b) the heavy MSSM Higgs bosons; and c) charged Higgs bosons in eγe\gamma collisions.Comment: 29 pages, 13 figures, contributed to Snowmass 200

    Ground Motion Studies at NuMI

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    Ground motion can cause significant deterioration in the luminosity of a linear collider. Vibration of numerous focusing magnets causes continuous misalignments, which makes the beam emittance grow. For this reason, understanding the seismic vibration of all potential LC sites is essential and related efforts in many sites are ongoing. In this document we summarize the results from the studies specific to Fermilab grounds as requested by the LC project leader at FNAL, Shekhar Mishra in FY04-FY06. The Northwestern group focused on how the ground motion effects vary with depth. Knowledge of depth dependence of the seismic activity is needed in order to decide how deep the LC tunnel should be at sites like Fermilab. The measurements were made in the NuMI tunnel, see Figure 1. We take advantage of the fact that from the beginning to the end of the tunnel there is a height difference of about 350 ft and that there are about five different types of dolomite layers. The support received allowed to pay for three months of salary of Michal Szleper. During this period he worked a 100% of his time in this project. That include one week of preparation: 2.5 months of data taking and data analysis during the full period of the project in order to guarantee that we were recording high quality data. We extended our previous work and made more systematic measurements, which included detailed studies on stability of the vibration amplitudes at different depths over long periods of time. As a consequence, a better control and more efficient averaging out of the daytime variation effects were possible, and a better study of other time dependences before the actual depth dependence was obtained. Those initial measurements were made at the surface and are summarized in Figure 2. All measurements are made with equipment that we already had (two broadband seismometers KS200 from GEOTECH and DL-24 portable data recorder). The offline data analysis took advantage of the full Fourier spectra information and the noise was properly subtracted. The basic formalism is summarized if Figure 3. The second objective was to make a measurement deeper under ground (Target hall, Absorber hall and Minos hall - 150 ft to 350 ft), which previous studies did not cover. All results are summarized in Figure 3 and 4. The measurements were covering a frequency range between 0.1 to 50 Hz. The data was taken continuously for at least a period of two weeks in each of the locations. We concluded that the dependence on depth is weak, if any, for frequencies above 1 Hz and not visible at all at lower frequencies. Most of the attenuation (factor of about 2-3) and damping of ground motion that is due to cultural activity at the surface is not detectable once we are below 150 ft underground. Therefore, accelerator currently under consideration can be build at the depth and there is no need to go deeper underground is built at Fermi National Laboratory

    Complementarity of a Low Energy Photon Collider and LHC Physics

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    We discuss the complementarity between the LHC and a low energy photon collider. We mostly consider the scenario, where the first linear collider is a photon collider based on dual beam technology like CLIC.Comment: 29 pages, 37 figure, LP-200

    Photon-Photon and Electron-Photon Colliders with Energies Below a TeV

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    We investigate the potential for detecting and studying Higgs bosons in γγ\gamma\gamma and eγe\gamma collisions at future linear colliders with energies below a TeV. Our study incorporates realistic γγ\gamma\gamma spectra based on available laser technology, and NLC and CLIC acceleration techniques. Results include detector simulations. We study the cases of: a) a SM-like Higgs boson based on a devoted low energy machine with see200\sqrt{s_{ee}}\le 200 GeV; b) the heavy MSSM Higgs bosons; and c) charged Higgs bosons in eγe\gamma collisions.We investigate the potential for detecting and studying Higgs bosons in γγ\gamma\gamma and eγe\gamma collisions at future linear colliders with energies below a TeV. Our study incorporates realistic γγ\gamma\gamma spectra based on available laser technology, and NLC and CLIC acceleration techniques. Results include detector simulations. We study the cases of: a) a SM-like Higgs boson based on a devoted low energy machine with see200\sqrt{s_{ee}}\le 200 GeV; b) the heavy MSSM Higgs bosons; and c) charged Higgs bosons in eγe\gamma collisions

    Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

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    Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

    Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an