8,461 research outputs found

    ICANOE and OPERA experiments at the LNGS/CNGS

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    We discuss two experiments ICANOE and OPERA that have been proposed within the context of long-baseline and atmospheric neutrino experiments in Europe. The joint ICANOE/OPERA program aims at further improving our understanding of the effect seen in atmospheric neutrinos. This program is based on (1) a continuation of the observation of atmospheric neutrinos with the improved technique of ICANOE/ICARUS (2) a sensitive numu->nue and numu->nutau appearance program with the accelerator neutrinos coming from CERN (CNGS) from a distance of 730 km.Comment: 8 pages; Invited talk at the XIX International Conference on Neutrino Physics and Astrophysics (Neutrino 2000), Sudbury, Canada, June 16-21, 2000; new version fix typo

    A three-dimensional wavelet based multifractal method : about the need of revisiting the multifractal description of turbulence dissipation data

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    We generalize the wavelet transform modulus maxima (WTMM) method to multifractal analysis of 3D random fields. This method is calibrated on synthetic 3D monofractal fractional Brownian fields and on 3D multifractal singular cascade measures as well as their random function counterpart obtained by fractional integration. Then we apply the 3D WTMM method to the dissipation field issue from 3D isotropic turbulence simulations. We comment on the need to revisiting previous box-counting analysis which have failed to estimate correctly the corresponding multifractal spectra because of their intrinsic inability to master non-conservative singular cascade measures.Comment: 5 pages, 3figures, submitted to Phys. Rev. Let

    Nuclear Parton Distributions - a DGLAP Analysis

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    Nuclear parton distributions fA(x,Q2)f_A(x,Q^2) are studied within a framework of the DGLAP evolution. Measurements of F2A/F2DF_2^A/F_2^D in deep inelastic lAlA collisions, and Drell--Yan dilepton cross sections measured in pApA collisions are used as constraints. Also conservation of momentum and baryon number is required. It is shown that the calculated Q2Q^2 evolution of F2Sn/F2CF_2^{\rm Sn}/F_2^{\rm C} agrees very well with the recent NMC data, and that the ratios RfA=fA/fR_f^A=f_A/f are only moderately sensitive to the choice of a specific modern set of free parton distributions. For general use, we offer a numerical parametrization of RfA(x,Q2)R_f^A(x,Q^2) for all parton flavours ff in A>2A>2, and at 106x110^{-6}\le x \le 1 and 2.25GeV2Q2104GeV22.25 {\rm GeV}^2\le Q^2\le 10^4 {\rm GeV}^2.Comment: Talk in Quark Matter '99, 5 pages, includes 3 eps-figure

    Diffraction for non-believers

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    Diffractive reactions involving a hard scale can be understood in terms of quarks and gluons. These reactions have become a valuable tool for investigating the low-x structure of the proton and the behavior of QCD in the high-density regime, and they may provide a clean environment to study or even discover the Higgs boson at the LHC. In this paper we give a brief introduction to the description of diffraction in QCD. We focus on key features studied in ep collisions at HERA and outline challenges for understanding diffractive interactions at the LHC.Comment: 23 pages, 26 figures. Contributed to the Proceedings of the Workshop on HERA and the LHC, DESY and CERN, 2004-200

    Nuclear modification difference between u_v and d_v distributions and its relation to NuTeV sin^2 theta_W anomaly

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    We investigate a possible nuclear correction to the NuTeV measurement of the weak-mixing angle sin^2 theta_W. In particular, a nuclear modification difference between u_v and d_v distributions contributes to the NuTeV measurement with the iron target. First, the modification differenceis determined by a chi^2 analysis so as to reproduce nuclear data on the structure function F_2 and Drell-Yan processes. Then, taking the NuTeV kinematics into account, we calculate a contribution to the sin^2 theta_W determination. In addition, its uncertainty is estimated by the Hessian method. Although the uncertainty becomes comparable to the NuTeV deviation, the effect is not large enough to explain the whole NuTeV sin^2 theta_W anomaly at this stage. However, it is difficult to determine such a nuclear modification difference, so that we need further investigations on the difference and its effect on the NuTeV anomaly.Comment: 6 pages,3 figure

    Structure function results from H1

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    New structure function results from H1 are presented. The measurements cover a huge kinematical range for Q^2, the four momentum transfer squared, from 0.35, GeV^2 to 30,000, GeV^2, and for Bjorken x between \sim 5\cdot 10^{-6} and 0.65. At Q^2>100, GeV^2, full HERA, I data have been analyzed. The data are compared with a new QCD analysis. The impact of the HERA, I data on the parton density functions is discussed.Comment: 8 page

    A Spectrometer to Study Elastic and Diffractive Physics at LHC

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    The possibility to study elastic and diffractive physics in pp collisions at LHC is investigated. For this purpose we have considered detectors close to the beam in conjunction with the magnetic elements of the accelerator to provide a high precision spectrometer for very forward final state protons. The geometrical acceptance is given and momentum resolution is calculated for different spatial resolution detectors.Comment: 26 pages, 13 figures, Latex, submitted in International Journal of Modern Physics

    A Systematic Study of Power Corrections from World Deep Inelastic Scattering Measurements

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    By performing an analysis in moment space using high statistics DIS world data, we extract the values of both the QCD parameter ΛMSˉ(4)\Lambda^{(4)}_{\bar{MS}} up to NLO and of the power corrections to the proton structure function, F2F_2. At variance with previous analyses, the use of moments allows us to extend the kinematical range to larger values of xx, where we find that power corrections are quantitatively more important. Our results are consistent with the nn dependence predicted by IR renormalon calculations. We discuss preliminary results on nuclear targets with the intent of illustrating a possible strategy to disentangle power corrections ascribed to IR renormalons from the ones generated dynamically e.g. from rescattering in the final state. The latter appear to be modified in nuclear targets.Comment: 4 pages, 2 figures, LateX with espcrc2 and epsfi
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