8,107 research outputs found

    Occupation probability of harmonic-oscillator quanta for microscopic cluster-model wave functions

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    We present a new and simple method of calculating the occupation probability of the number of total harmonic-oscillator quanta for a microscopic cluster-model wave function. Examples of applications are given to the recent calculations including α+n+n\alpha+n+n-model for 6^6He, α+t+n+n\alpha+t+n+n-model for 9^9Li, and α+α+n\alpha+\alpha+n-model for 9^9Be as well as the classical calculations of α+p+n\alpha+p+n-model for 6^6Li and α+α+α\alpha+\alpha+\alpha-model for 12^{12}C. The analysis is found to be useful for quantifying the amount of excitations across the major shell as well as the degree of clustering. The origin of the antistretching effect is discussed.Comment: 9 page

    Ab initio study of the photoabsorption of 4^4He

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    There are some discrepancies in the low energy data on the photoabsorption cross section of 4^4He. We calculate the cross section with realistic nuclear forces and explicitly correlated Gaussian functions. Final state interactions and two- and three-body decay channels are taken into account. The cross section is evaluated in two methods: With the complex scaling method the total absorption cross section is obtained up to the rest energy of a pion, and with the microscopic RR-matrix method both cross sections 4^4He(γ,p\gamma, p)3^3H and 4^4He(γ,n\gamma, n)3^3He are calculated below 40\,MeV. Both methods give virtually the same result. The cross section rises sharply from the 3^3H+pp threshold, reaching a giant resonance peak at 26--27\,MeV. Our calculation reproduces almost all the data above 30\,MeV. We stress the importance of 3^3H+pp and 3^3He+nn cluster configurations on the cross section as well as the effect of the one-pion exchange potential on the photonuclear sum rule.Comment: 15 pages, 12 figure

    Development of High Granulated Straw Chambers of Large Sizes

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    We have developed the baseline design for the straw drift tube tracking detectors for high rate environment application. The low-mass inner straw elements and the technology of the multianode straws assembly was devised and checked. The prototype chamber was constructed and studied the granularity of similar chambers can be reduced to one cm2. Submitted to Physics of Elementary Particles and Atomic Nuclei, LettersComment: 6 pages, 10 figure

    Non-universal scalar-tensor theories and big bang nucleosynthesis

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    We investigate the constraints that can be set from big-bang nucleosynthesis on two classes of models: extended quintessence and scalar-tensor theories of gravity in which the equivalence principle between standard matter and dark matter is violated. In the latter case, and for a massless dilaton with quadratic couplings, the phase space of theories is investigated. We delineate those theories where attraction toward general relativity occurs. It is shown that big-bang nucleosynthesis sets more stringent constraints than those obtained from Solar system tests.Comment: 28 pages, 20 figure

    Miniaturization of High-Frequency Carrier-Type Thin-Film Magnetic Field Sensor Using Laminated Film

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    We examined a laminated high-frequency carrier-type thin-film magnetic field sensor that consists of CoNbZr soft magnetic films with Nb nonmagnetic conductive interlayer. The lamination can change domain structure of the sensor and obtain high sensitivity. An impedance change of 6 /spl Omega/ and a gain of 43 k/spl Omega//T was achieved when the length of the laminated sensor was 1 mm. The gain is four times larger than that of a monolayer sensor

    Reduction techniques of the back gate effect in the SOI Pixel Detector

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    We have fabricated monolithic pixel sensors in 0.2 μm Silicon-On-Insulator (SOI) CMOS technology, consisting of a thick sensor layer and a thin circuit layer with an insulating buried-oxide, which has many advantages. However, it has been found that the applied electric field in the sensor layer also affects the transistor operation in the adjacent circuit layer. This limits the applicable sensor bias well below the full depletion voltage. To overcome this, we performed a TCAD simulation and added an additional p-well (buried pwell) in the SOI process. Designs and preliminary results are presented

    Intersecting Solitons, Amoeba and Tropical Geometry

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    We study generic intersection (or web) of vortices with instantons inside, which is a 1/4 BPS state in the Higgs phase of five-dimensional N=1 supersymmetric U(Nc) gauge theory on R_t \times (C^\ast)^2 \simeq R^{2,1} \times T^2 with Nf=Nc Higgs scalars in the fundamental representation. In the case of the Abelian-Higgs model (Nf=Nc=1), the intersecting vortex sheets can be beautifully understood in a mathematical framework of amoeba and tropical geometry, and we propose a dictionary relating solitons and gauge theory to amoeba and tropical geometry. A projective shape of vortex sheets is described by the amoeba. Vortex charge density is uniformly distributed among vortex sheets, and negative contribution to instanton charge density is understood as the complex Monge-Ampere measure with respect to a plurisubharmonic function on (C^\ast)^2. The Wilson loops in T^2 are related with derivatives of the Ronkin function. The general form of the Kahler potential and the asymptotic metric of the moduli space of a vortex loop are obtained as a by-product. Our discussion works generally in non-Abelian gauge theories, which suggests a non-Abelian generalization of the amoeba and tropical geometry.Comment: 39 pages, 11 figure

    Atomic Deuterium Adsorbed on the Surface of Liquid Helium

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    We investigate deuterium atoms adsorbed on the surface of liquid helium in equilibrium with a vapor of atoms of the same species. These atoms are studied by a sensitive optical method based on spectroscopy at a wavelength of 122 nm, exciting the 1S-2P transition. We present a direct measurement of the adsorption energy of deuterium atoms on helium and show evidence for the existence of resonantly enhanced recombination of atoms residing on the surface to molecules.Comment: 6 pages 4 figure
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