4,755 research outputs found
Pi N sigma-term and chiral-odd twist-3 distribution function e(x) of the nucleon in the chiral quark soliton model
The isosinglet combination of the chiral-odd twist-3 distribution function
of the nucleon has outstanding properties that its first moment
is proportional to the well-known sigma-term and that it contains a
-function singularity at . These two features are inseparably
connected in that the above sum rule would be violated, if there is no such a
singularity in . Very recently, we found that the physical
origin of this -function singularity can be traced back to the
long-range quark-quark correlation of scalar type, which signals the
spontaneous chiral symmetry breaking of the QCD vacuum. The main purpose of the
present paper is to give complete theoretical predictions for the chiral-odd
twist-3 distribution function of each flavor on the basis of the
chiral quark soliton model, without recourse to the derivative expansion type
approximation. These theoretical predictions are then compared with the
empirical information extracted from the CLAS data of the semi-inclusive DIS
processes by assuming the Collins mechanism only. A good agreement with the
CLAS data is indicative of a sizable violation of the sigma-term sum
rule, or equivalently, the existence of a -function singularity in
.Comment: 35 pages, 10 figure
Belle II iTOP Optics: Design, Construction and Performance
The imaging-Time-of-Propogation (iTOP) counter is a new type of ring-imaging
Cherenkov counter developed for particle identification at the Belle II
experiment. It consists of 16 modules arranged azimuthally around the beam
line. Each module consists of one mirror, one prism and two quartz bar
radiators. Here we describe the design, acceptance test, alignment, gluing and
assembly of the optical components. All iTOP modules have been successfully
assembled and installed in the Belle II detector by the middle of 2016. After
installation, laser and cosmic ray data have been taken to test the performance
of the modules. First results from these tests are presented.Comment: Proceedings of TIPP 2017, May 22 - 26, Beijing, China, 2017;
University of Cincinnati preprint UCHEP-17-07. arXiv admin note: text overlap
with arXiv:1709.0993
Jet-fluid string formation and decay in high-energy heavy-ion collisions
We propose a new hadronization mechanism, jet-fluid string (JFS) formation
and decay, to understand observables in intermediate to high- regions
comprehensively. In the JFS model, hard partons produced in jet lose their
energy in traversing the QGP fluid, which is described by fully
three-dimensional hydrodynamic simulations. When a jet parton escapes from the
QGP fluid, it picks up a partner parton from a fluid and forms a color singlet
string, then it decays to hadrons. We find that high- values in JFS
are about two times larger than in the independent fragmentation model.Comment: 6 pages, 2 figures; Proceeding for poster sessions at Quark Matter
2006, Shanghai, China, 14-20 November 2006; to appear in Int. J. of Mod.
Phys.
Indication of intrinsic spin Hall effect in 4d and 5d transition metals
We have investigated spin Hall effects in 4 and 5 transition metals,
Nb, Ta, Mo, Pd and Pt, by incorporating the spin absorption method in the
lateral spin valve structure; where large spin current preferably relaxes into
the transition metals, exhibiting strong spin-orbit interactions. Thereby
nonlocal spin valve measurements enable us to evaluate their spin Hall
conductivities. The sign of the spin Hall conductivity changes systematically
depending on the number of electrons. This tendency is in good agreement
with the recent theoretical calculation based on the intrinsic spin Hall
effect.Comment: 5 pages, 4 figure
Mechanical Behavior of Cohesive Soil under Repeated Loading
A new triaxial apparatus which can control the stress condition automatically in a constant mean principal stress under repeated loading was developed, Mechanical behavior of cohesive soils under repeated loading was investigated. Excess pore water pressure generated in loading cycles was measured and the experimental results were interpreted in terms of effective stress by using elasto-plastic models
Search for a Ridge Structure Origin with Shower Broadening and Jet Quenching
We investigate the role of jet and shower parton broadening by the strong
colour field in the - correlation of high
particles. When anisotropic momentum broadening () is
given to jet and shower partons in the initial stage, a ridge-like structure is
found to appear in the two hadron correlation. The ratio of the peak to the
pedestal yield is overestimated.Comment: Talk given at 20th Int. Conf. on Ultra-Relativistic Nucleus-Nucleus
Collisions, Jaipur, India, Feb.4-10, 200
Nucleosynthesis in novae: experimental progress in the determination of nuclear reaction rates
The sources of nuclear uncertainties in nova nucleosynthesis have been
identified using hydrodynamical nova models. Experimental efforts have followed
and significantly reduced those uncertainties. This is important for the
evaluation of nova contribution to galactic chemical evolution, gamma--ray
astronomy and possibly presolar grain studies. In particular, estimations of
expected gamma-ray fluxes are essential for the planning of observations with
existing or future satellites.Comment: Invited contribution to the "Origin of Matter and Evolution of
Galaxies" conference (OMEG07) with additional and color figure
SuprimeCam Observation of Sporadic Meteors during Perseids 2004
We report the serendipitous findings of 13 faint meteors and 44 artificial
space objects by Subaru SuprimeCam imaging observations during 11-16 August
2004. The meteors, at about 100km altitude, and artificial satellites/debris in
orbit, at 500km altitude or higher, were clearly discriminated by their
apparent defocused image sizes. CCD photometry of the 13 meteors, including 1
Perseid, 1 Aquarid, and 11 sporadic meteors, was performed. We defined a peak
video-rate magnitude by comparing the integrated photon counts from the
brightest portion of the track traversed within 33ms to those from a 0-mag star
during the same time duration. This definition gives magnitudes in the range
4.0< V_{vr} <6.4 and 4.1< I_{vr}<5.9 for these 13 meteors. The corresponding
magnitude for virtual naked-eye observers could be somewhat fainter especially
for the V-band observation, in which the [OI] 5577 line lasting about 1 sec as
an afterglow could contribute to the integrated flux of the present 5-10 min
CCD exposures. Although the spatial resolution is insufficient to resolve the
source size of anything smaller than about 1 m, we developed a new estimate of
the collisionally excited column diameter of these meteors. A diameter as small
as a few mm was derived from their collisionally excited photon rates, meteor
speed, and the volume density of the oxygen atoms at the 100km altitude. The
actual column diameter of the radiating zone, however, could be as large as few
100m because the excited atoms travel that distance before they emit forbidden
lines in 0.7 sec of its average lifetime. Among the 44 artificial space
objects, we confirmed that 17 were cataloged satellites/space debris.Comment: 14 pages, 13 figures, 5 tables, submitted to PAS
- …