8,107 research outputs found
Occupation probability of harmonic-oscillator quanta for microscopic cluster-model wave functions
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 -model for He, -model for
Li, and -model for Be as well as the classical
calculations of -model for Li and -model
for 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 He
There are some discrepancies in the low energy data on the photoabsorption
cross section of He. 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 -matrix method both cross sections He()H
and He()He are calculated below 40\,MeV. Both methods give
virtually the same result. The cross section rises sharply from the H+
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
H+ and He+ 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
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
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
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
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
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
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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