1,644 research outputs found

    On the Inverse Problem Relative to Dynamics of the w Function

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    In this paper we shall study the inverse problem relative to dynamics of the w function which is a special arithmetic function and shall get some results.Comment: 11 page

    Fabrication of implanted 7^{7}Be targets

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    Benchmark calculations for elastic fermion-dimer scattering

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    We present continuum and lattice calculations for elastic scattering between a fermion and a bound dimer in the shallow binding limit. For the continuum calculation we use the Skorniakov-Ter-Martirosian (STM) integral equation to determine the scattering length and effective range parameter to high precision. For the lattice calculation we use the finite-volume method of L\"uscher. We take into account topological finite-volume corrections to the dimer binding energy which depend on the momentum of the dimer. After subtracting these effects, we find from the lattice calculation kappa a_fd = 1.174(9) and kappa r_fd = -0.029(13). These results agree well with the continuum values kappa a_fd = 1.17907(1) and kappa r_fd = -0.0383(3) obtained from the STM equation. We discuss applications to cold atomic Fermi gases, deuteron-neutron scattering in the spin-quartet channel, and lattice calculations of scattering for nuclei and hadronic molecules at finite volume.Comment: 16 pages, 5 figure

    Dessins, their delta-matroids and partial duals

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    Given a map M\mathcal M on a connected and closed orientable surface, the delta-matroid of M\mathcal M is a combinatorial object associated to M\mathcal M which captures some topological information of the embedding. We explore how delta-matroids associated to dessins d'enfants behave under the action of the absolute Galois group. Twists of delta-matroids are considered as well; they correspond to the recently introduced operation of partial duality of maps. Furthermore, we prove that every map has a partial dual defined over its field of moduli. A relationship between dessins, partial duals and tropical curves arising from the cartography groups of dessins is observed as well.Comment: 34 pages, 20 figures. Accepted for publication in the SIGMAP14 Conference Proceeding

    Magnetic Moment of the Fragmentation Aligned 61Fe(9/2)+ Isomer

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    We report on the g factor measurement of the isomer in 61Fe^{61}Fe (E∗=861keVE^{*}=861 keV). The isomer was produced and spin-aligned via a projectile-fragmentation reaction at intermediate energy, the Time Dependent Perturbed Angular Distribution (TDPAD) method being used for the measurement of the g factor. For the first time, due to significant improvements of the experimental technique, an appreciable residual alignment of the isomer has been observed, allowing a precise determination of its g factor: g=−0.229(2)g=-0.229(2). Comparison of the experimental g factor with shell-model and mean field calculations confirms the 9/2+9/2^+ spin and parity assignments and suggests the onset of deformation due to the intrusion of Nilsson orbitals emerging from the Îœg9/2\nu g_{9/2}.Comment: 4 figures. Submitted to Phys. Rev. Let

    Confirmation of Parity Violation in the Gamma Decay of 180Hfm^{180}Hf^{m}

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    This paper reports measurements using the technique of On Line Nuclear Orientation (OLNO) which reexamine the gamma decay of isomeric 180^{\rm 180}Hfm^{\rm m} and specifically the 501 keV 8−^{\rm -} -- 6+^{\rm +} transition. The irregular admixture of E2 to M2/E3 multipolarity in this transition, deduced from the forward-backward asymmetry of its angular distribution, has for decades stood as the prime evidence for parity mixing in nuclear states. The experiment, based on ion implantation of the newly developed mass-separated 180^{\rm 180}Hfm^{\rm m} beam at ISOLDE, CERN into an iron foil maintained at millikelvin temperatures, produces higher degrees of polarization than were achieved in previous studies of this system. The value found for the E2/M2 mixing ratio, Ï”\epsilon = -0.0324(16)(17), is in close agreement with the previous published average value Ï”\epsilon = - 0.030(2), in full confirmation of the presence of the irregular E2 admixture in the 501 keV transition. The temperature dependence of the forward-backward asymmetry has been measured over a more extended range of nuclear polarization than previously possible, giving further evidence for parity mixing of the 8−^{\rm -} and 8+^{\rm +} levels and the deduced E2/M2 mixing ratio.Comment: 28 pages, 9 figures, accepted for publication in Physical Review

    A new measurement of the 7Li(d,p)8Li cross section and consequences for 7Be(p,gamma)8B

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    A novel scheme for measuring the cross section of the 7Be(p,gamma)8B reaction, the major source of high energy neutrinos from t he sun, is presented. The scheme involves a strictly uniform particle beam and overcomes some of the recognized experimental uncertainties of previous measurements. A new measurement of sigma[7Li(d,p)8Li] has been carried out using this setup,and the present value of sigma[7Li(d,p)8Li] = 155(8) mbarn at the top of the E_d(lab.)= 776 keV resonance is compared to previous measurements. A new issue regarding both the (d,p) and (p,gamma) reactions has been examined: reaction-product nuclei which are backscattered out of the target. Measurements and simulations carried out in the course of this investigation are presented and discussed in the context of possible effects on the measured cross sections of these reactions.Comment: 4 figure
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