2,568 research outputs found
Quasi-Elastic Reaction and Spin Response Functions of the Deuteron
We calculated response functions of the deuteron for charge exchange
processes, including the final state interaction between two protons. Using
them we evaluated the double differential cross section and polarization
observables of by means of plane wave impulse
approximation with an optimal factorization. Calculation well reproduced the
shape of the energy spectra of the cross section, though somewhat overestimated
the magnitude. It also reproduced the spin observables well.Comment: 19 pages of LaTeX (4 figures not included, hard copy available upon
request), UT-Komaba 93-2
Pionic Modes Studied by Quasielastic (\vec{p}, \vec{n}) Reactions
It has long been expected that the pionic modes show some collective
phenomena such as the pion condensation in the high density nuclear matter and
its precursor phenomena in the ordinary nuclei. Here we show an evidence of the
precursor observed in the isovector spin longitudinal cross sections ID_q of
the quasielastic 12C, 40Ca (\vec{p}, \vec{n}) reactions at T_p = 346 and 494MeV
with the momentum transfer q = 1.7fm-1. Another aim of this report is to
evaluate the Landau-Migdal parameters g'_{NN}, g'_{N\Delta} and
g'_{\Delta\Delta} at the large momentum region from the above reactions. We
obtained g'_{NN} \approx 0.6-0.7, g'_{N\Delta} \approx 0.3-0.4. The results are
consistent with those at the small momentum region, which are obtained from the
Gamov-Teller strength distribution.Comment: 6 pages, 4 figures, proceedings for 7th International Spring Seminar
on Nuclear Physics "Challenges of Nuclear Structure" at Maiori, Ital
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A Framework for 3D Pushbroom Imaging
Pushbroom cameras produce one-dimensional images of a scene with high resolution at a high frame-rate. As a result, they provide superior data compared to conventional two-dimensional cameras in cases where the scene of interest can be temporally scanned. In this paper, we consider the problem of recovering the structure of a scene using a set of pushbroom cameras. Although pushbroom cameras have been used to recover scene structure in the past, the algorithms for recovery were developed separately for different camera motions such as translation and rotation. In this paper, we present a general framework of structure recovery for pushbroom cameras with 6 degree-of-freedom motion. We analyze the translation and rotation cases using our framework and demonstrate that several previous results are really special cases of our result. Using this framework, we also show that three or more pushbroom cameras can be used to compute scene structure as well as motion of translation or rotation. We conclude with a set of experiments that demonstrate the use of pushbroom imaging to recover structure from unknown motion
Chiral charge-density-waves
We discovered the chirality of charge density waves (CDW) in 1T-TiSe by
using scanning tunnelling microscopy (STM) and optical ellipsometry. We found
that the CDW intensity becomes , where (i =1, 2, 3) is the amplitude of the tunnelling current
contributed by the CDWs. There were two states, in which the three intensity
peaks of the CDW decrease \textit{clockwise} and \textit{anticlockwise} when we
index each nesting vector in order of intensity in the Fourier transformation
of the STM images. The chirality in CDW results in the three-fold symmetry
breaking. Macroscopically, two-fold symmetry was indeed observed in optical
measurement. We propose the new generalized CDW chirality H_{CDW} \equiv
{\boldmath q_1} \cdot ({\boldmath q_2}\times {\boldmath q_3}), where
{\boldmath q_i} are the nesting vectors, which is independent of the
symmetry of components. The nonzero - the triple-{\boldmath q}
vectors do not exist in an identical plane in the reciprocal space - should
induce a real-space chirality in CDW system.Comment: 12 pages, 4 figure
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