230 research outputs found

    On length-weight relationships. Part II: Computing mean weights from length statistics

    Get PDF
    Length-weight relationships, Statistical analysis

    Model Analysis of Time Reversal Symmetry Test in the Caltech Fe-57 Gamma-Transition Experiment

    Full text link
    The CALTECH gamma-transition experiment testing time reversal symmetry via the E2/M1 mulipole mixing ratio of the 122 keV gamma-line in Fe-57 has already been performed in 1977. Extending an earlier analysis in terms of an effective one-body potential, this experiment is now analyzed in terms of effective one boson exchange T-odd P-even nucleon nucleon potentials. Within the model space considered for the Fe-57 nucleus no contribution from isovector rho-type exchange is possible. The bound on the coupling strength phi_A from effective short range axial-vector type exchange induced by the experimental bound on sin(eta) leads to phi_A < 10^{-2}.Comment: 5 pages, RevTex 3.

    Low Q^2 Jet Production at HERA and Virtual Photon Structure

    Get PDF
    The transition between photoproduction and deep-inelastic scattering is investigated in jet production at the HERA ep collider, using data collected by the H1 experiment. Measurements of the differential inclusive jet cross-sections dsigep/dEt* and dsigmep/deta*, where Et* and eta* are the transverse energy and the pseudorapidity of the jets in the virtual photon-proton centre of mass frame, are presented for 0 < Q2 < 49 GeV2 and 0.3 < y < 0.6. The interpretation of the results in terms of the structure of the virtual photon is discussed. The data are best described by QCD calculations which include a partonic structure of the virtual photon that evolves with Q2.Comment: 20 pages, 5 Figure

    Hadron Production in Diffractive Deep-Inelastic Scattering

    Get PDF
    Characteristics of hadron production in diffractive deep-inelastic positron-proton scattering are studied using data collected in 1994 by the H1 experiment at HERA. The following distributions are measured in the centre-of-mass frame of the photon dissociation system: the hadronic energy flow, the Feynman-x (x_F) variable for charged particles, the squared transverse momentum of charged particles (p_T^{*2}), and the mean p_T^{*2} as a function of x_F. These distributions are compared with results in the gamma^* p centre-of-mass frame from inclusive deep-inelastic scattering in the fixed-target experiment EMC, and also with the predictions of several Monte Carlo calculations. The data are consistent with a picture in which the partonic structure of the diffractive exchange is dominated at low Q^2 by hard gluons.Comment: 16 pages, 6 figures, submitted to Phys. Lett.

    Energy Flow in the Hadronic Final State of Diffractive and Non-Diffractive Deep-Inelastic Scattering at HERA

    Get PDF
    An investigation of the hadronic final state in diffractive and non--diffractive deep--inelastic electron--proton scattering at HERA is presented, where diffractive data are selected experimentally by demanding a large gap in pseudo --rapidity around the proton remnant direction. The transverse energy flow in the hadronic final state is evaluated using a set of estimators which quantify topological properties. Using available Monte Carlo QCD calculations, it is demonstrated that the final state in diffractive DIS exhibits the features expected if the interaction is interpreted as the scattering of an electron off a current quark with associated effects of perturbative QCD. A model in which deep--inelastic diffraction is taken to be the exchange of a pomeron with partonic structure is found to reproduce the measurements well. Models for deep--inelastic epep scattering, in which a sizeable diffractive contribution is present because of non--perturbative effects in the production of the hadronic final state, reproduce the general tendencies of the data but in all give a worse description.Comment: 22 pages, latex, 6 Figures appended as uuencoded fil

    A Search for Selectrons and Squarks at HERA

    Get PDF
    Data from electron-proton collisions at a center-of-mass energy of 300 GeV are used for a search for selectrons and squarks within the framework of the minimal supersymmetric model. The decays of selectrons and squarks into the lightest supersymmetric particle lead to final states with an electron and hadrons accompanied by large missing energy and transverse momentum. No signal is found and new bounds on the existence of these particles are derived. At 95% confidence level the excluded region extends to 65 GeV for selectron and squark masses, and to 40 GeV for the mass of the lightest supersymmetric particle.Comment: 13 pages, latex, 6 Figure

    Current state and future of pediatric allergology in Europe: A road map

    Get PDF
    The history of pediatric allergology (PA) in Europe is relatively youthful, dating back to 1984, when a small group of pediatricians founded the European Working Group on Pediatric Allergy and Immunology—later giving rise to ESPACI (European Society on Pediatric Allergology and Clinical Immunology). In 1990, the first dedicated journal, Pediatric Allergy and Immunology (PAI), was founded. There are striking differences across Europe, and even within European countries, in relation to the training pathways for doctors seeing children with allergic disease(s). In 2016, the EAACIClemens von Pirquet Foundation (CvP) organized and sponsored a workshop with the European Academy of Allergy and Clinical Immunology (EAACI) Pediatric Section. This collaboration focussed on the future of PA and specifically on education, research, and networking/ advocacy. The delegates representing many countries across Europe have endorsed the concept that optimal care of children with allergic diseases is delivered by pediatricians who have received dedicated training in allergy, or allergists who have received dedicated training in pediatrics. In order to meet the needs of children and families with allergic disease(s), the pediatric allergist is highly encouraged to develop several networks. Our challenge is to reinforce a clear strategic approach to scientific excellence to across our member base and to ensure and enhance the relevance of European pediatric research in allergy. With research opportunities in basic, translational, clinical, and epidemiologic trials, more trainees and trained specialists are needed and it is an exciting time to be a pediatric allergologist

    Improving Supervisor Evaluations Through the Use of Self Determination Contracts

    Get PDF
    Supervisor perceptions of employee competence in areas of work, social, and personal demands of the job often determine success or failure for the supported employee. This study involved three workers with disabilities who participated in a supported employment program. After being successfully hired in a job of their choosing, problems arose that jeopardized the successful completion of the placement phase. The workers used individualized self-determination contracts to improve supervisor evaluations. Specifically, they completed daily self-determination contracts to plan their work outcomes, manage their tasks, evaluate their performance, and make adjustments for their next opportunity to work. Results indicated that all three workers used self-determination strategies to improve their performance and meet the expectations of their respective employers.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

    A Measurement of the Proton Structure Function F ⁣2(x,Q2)F_{\!2}(x,Q^2)

    Full text link
    A measurement of the proton structure function F ⁣2(x,Q2)F_{\!2}(x,Q^2) is reported for momentum transfer squared Q2Q^2 between 4.5 GeV2GeV^2 and 1600 GeV2GeV^2 and for Bjorken xx between 1.81041.8\cdot10^{-4} and 0.13 using data collected by the HERA experiment H1 in 1993. It is observed that F ⁣2F_{\!2} increases significantly with decreasing xx, confirming our previous measurement made with one tenth of the data available in this analysis. The Q2Q^2 dependence is approximately logarithmic over the full kinematic range covered. The subsample of deep inelastic events with a large pseudo-rapidity gap in the hadronic energy flow close to the proton remnant is used to measure the "diffractive" contribution to F ⁣2F_{\!2}.Comment: 32 pages, ps, appended as compressed, uuencoded fil
    corecore