9,568 research outputs found

    Theory of Complex Scattering Lengths

    Full text link
    We derive a generalized Low equation for the T-matrix appropriate for complex atom-molecule interaction. The properties of this new equation at very low energies are studied and the complex scattering length and effective range are derived.Comment: 9 page

    Two-step nuclear reactions: The Surrogate Method, the Trojan Horse Method and their common foundations

    Full text link
    In this Letter I argue that the Surrogate Method, used to extract the fast neutron capture cross section on actinide target nuclei, which has important practical application for the next generation of breeder reactors, and the Trojan Horse Method employed to extract reactions of importance to nuclear astrophysics, have a common foundation, the Inclusive Non-Elastic Breakup (INEB)Theory. Whereas the Surrogate Method relies on the premise that the extracted neutron cross section in a (d,p) reaction is predominantly a compound nucleus one, the Trojan Horse Method, assumes a predominantly direct process for the secondary reaction induced by the surrogate fragment. In general, both methods contain both direct and compound contributions, and I show how theses seemingly distinct methods are in fact the same but at different energies and different kinematic regions. The unifying theory is the rather well developed INEB theory.Comment: 3 pages. Accepted for publication in the European Physical Journal A (2017

    Toward a microscopic description of reactions involving exotic nuclei

    Full text link
    We propose an extension of the Continuum Discretized Coupled Channels (CDCC) method, where the projectile is described by a microscopic cluster model. This microscopic generalization (MCDCC) only relies on nucleon-target interactions, and therefore presents an important predictive power. Core excitations can be included without any further parameter. As an example we investigate the \lipb elastic scattering at Elab=27E_{lab}=27 and 35 MeV. The 7^7Li nucleus is known to present an α+t\alpha+t cluster structure, and is well described by the Resonating Group Method. An excellent agreement is obtained for the \lipb elastic cross sections, provided that breakup channels are properly included. We also present an application to inelastic scattering, and discuss future applications of the MCDCC.Comment: 5 pages, 3 figures, Physical Review Letters (2013) in pres

    Ultra cold neutrons: determination of the electric dipole moment and gravitational corrections via matter wave interferometry

    Full text link
    We propose experiments using ultra cold neutrons which can be used to determine the electric dipole moment of the neutron itself, a well as to test corrections to gravity as they are foreseen by string theories and Kaluza-Klein mechanisms.Comment: 3 pages, no figures, reference adde

    Anxiety during pregnancy among Sudanese pregnant women

    Get PDF
    Many women suffer psychological symptoms during pregnancy but few studies have examined anxiety among pregnant ladies in relation to the level of education, previous bad obstetrical history and female circumcision. Aims: To determine frequency of anxiety among Sudanese women as related to pregnancy and customs related factors. Methods: 50 pregnant ladies and 50 matched controls were studied at the antenatal clinics of three major hospitals in Khartoum utilizing the Taylor Manifest Anxiety Scale. Data was fed to SPSS and significance was taken at P 0.05. Results: Three of the variables in the study were independently associated with anxiety during pregnancy. These were previous still birth (P 0.0370), female genital mutilation (pharaonic circumcision) (P 0.0070) and the low level of education (P 0.004). Keywords: pregnancy; anxietySudan Journal of Medical Science Vol. 1 (2) December 2006: 127-13

    Condensed vortex ground states of rotating Bose-Einstein condensate in harmonic atomic trap

    Full text link
    We study a system of NN Bose atoms trapped by a symmetric harmonic potential, interacting via weak central forces. Considering the ground state of the rotating system as a function of the two conserved quantities, the total angular momentum and its collective component, we develop an algebraic approach to derive exact wave functions and energies of these ground states. We describe a broad class of the interactions for which these results are valid. This universality class is defined by simple integral condition on the potential. Most of the potentials of practical interest which have pronounced repulsive component belong to this universality class.Comment: 34 pages, 10 ps figures, minor revisions, to be publ. in Ann. Phy
    • …
    corecore