713 research outputs found

    Novel Transversity Properties in Semi-Inclusive Deep Inelastic Scattering

    Get PDF
    The TT-odd distribution functions contributing to transversity properties of the nucleon and their role in fueling nontrivial contributions to azimuthal asymmetries in semi-inclusive deep inelastic scattering are investigated. We use a dynamical model to evaluate these quantities in terms of HERMES kinematics.Comment: 5 pages revtex; 5 eps figures. References added. To appear as a Rapid Communication in Physical Review

    Weak gravity in DGP braneworld model

    Get PDF
    We analyze the weak gravity in the braneworld model proposed by Dvali-Gabadadze-Porrati, in which the unperturbed background spacetime is given by five dimensional Minkowski bulk with a brane which has the induced Einstein Hilbert term. This model has a critical length scale rcr_c. Naively, we expect that the four dimensional general relativity (4D GR) is approximately recovered at the scale below rcr_c. However, the simple linear perturbation does not work in this regime. Only recently the mechanism to recover 4D GR was clarified under the restriction to spherically symmetric configurations, and the leading correction to 4D GR was derived. Here, we develop an alternative formulation which can handle more general perturbations. We also generalize the model by adding bulk cosmological constant and the brane tension.Comment: 7 pages, 1 figure, references adde

    One-Loop Helicity Amplitudes for Parton Level Virtual Compton Scattering

    Full text link
    We calculate the one-loop QCD virtual corrections to all helicity amplitudes for parton level virtual Compton scattering processes. We include the amplitudes both on quark target process γ∗q→γq\gamma^* q\to\gamma q and on gluon target process γ∗g→γg\gamma^*g\to\gamma g. The infrared pole structure of the amplitudes is in agreement with the prediction of Catani's general formalism for the singularities of one-loop amplitudes, while expressions for the finite remainder are given in terms of logarithms and dilogarithms that are real in the physical region.Comment: 16 pages, 2 figures, detailed comparison with DVCS include

    On the nature of the z=0 X-ray absorbers: I. Clues from an external group

    Full text link
    Absorption lines of OVII at redshift zero are observed in high quality Chandra spectra of extragalactic sightlines. The location of the absorber producing these lines, whether from the corona of the Galaxy or from the Local Group or even larger scale structure, has been a matter of debate. Here we study another poor group like our Local Group to understand the distribution of column density from galaxy to group scales. We show that we cannot yet rule out the group origin of z=0 systems. We further argue that the debate over Galactic vs. extragalactic origin of z=0 systems is premature as they likely contain both components and predict that future higher resolution observations will resolve the z=0 systems into multiple components.Comment: Submitted to ApJ

    Light Gluinos and the Parton Structure of the Nucleon

    Full text link
    We study the effects of light gluinos with mass below about 1 GeV on the nucleon parton densities and the running of alpha_(S). It is shown that from the available high-statistics DIS data no lower bound on the gluino mass can be derived. Also in the new kinematical region accessible at HERA the influence of such light gluinos on structure f unctions is found to be very small and difficult to detect. For use in more direct searches involving final state signatures we present a radiative estimate of the gluino distribution in the nucleon.Comment: 23 pages, LateX, 8 figures, MPI-PhT/94-22, LMU-3/9

    Navigating the Global Landscape of Nursing Informatics Research Collaboration: A Blueprint for Success

    Get PDF
    International collaboration is crucial in the field of nursing informatics research to enhance our ability to conduct globally relevant research that informs policy and practice. In this case study we describe how we have established an international research collaboration to evaluate nurses’ experiences of technology use during the pandemic. We firstly describe how the collaboration was created and the successes associated with our work, before highlighting the facilitators to make an international collaboration work. We also discuss the challenges we have encountered during this collaborative enterprise, to enable other researchers who wish to establish international collaborations and learn from our experiences

    Real and Virtual Compton Scattering off the Nucleon

    Get PDF
    A review is given of the very recent developments in the fields of real and virtual Compton scattering off the nucleon. Both real and virtual Compton scattering reactions are discussed at low outgoing photon energy where one accesses polarizabilities of the nucleon. The real Compton scattering at large momentum transfer is discussed which is asymptotically a tool to obtain information on the valence quark wave function of the nucleon. The rapid developments in deeply virtual Compton scattering and associated meson electroproduction reactions at high energy, high photon virtuality and small momentum transfer to the nucleon are discussed. A unified theoretical description of those processes has emerged over the last few years, which gives access to new, generalized parton distributions. The experimental status and perspectives in these fields are also discussed.Comment: 25 pages, 17 figure

    Generalized Parton Distributions at x->1

    Full text link
    Generalized parton distributions at large xx are studied in perturbative QCD approach. As x→1x\to 1 and at finite tt, there is no tt dependence for the GPDs which means that the active quark is at the center of the transverse space. We also obtain the power behavior: Hqπ(x,Ο,t)∌(1−x)2/(1−Ο2)H_q^\pi(x,\xi,t)\sim (1-x)^2/(1-\xi^2) for pion; Hq(x,Ο,t)∌(1−x)3/(1−Ο2)2H_q(x,\xi,t)\sim (1-x)^3/(1-\xi^2)^2 and Eq(x,Ο,t)∌(1−x)5/(1−Ο2)3f(Ο)E_q(x,\xi,t)\sim (1-x)^5/(1-\xi^2)^3f(\xi) for nucleon, where f(Ο)f(\xi) represents the additional dependence on Ο\xi.Comment: 7 pages, 2 figure
    • 

    corecore