1,695 research outputs found
Single Transverse-Spin Asymmetry in Large Open Charm Production at an Electron-Ion Collider
We discuss the single transverse-spin asymmetry (SSA) to be observed in the
-meson production with large transverse-momentum in semi-inclusive deep
inelastic scattering, . This contribution is
embodied as a twist-3 mechanism in the collinear factorization, which is
induced by purely gluonic correlation inside the transversely-polarized
nucleon, in particular, by the three-gluon correlation effects. The complete
formula for the corresponding SSA in the leading-order QCD is expressed in
terms of the four independent gluonic correlation functions and reveals the
five independent structures with respect to the dependence on the azimuthal
angle for the produced -meson. We present the numerical calculations of the
SSA formula at the kinematics relevant to a future Electron Ion Collider.Comment: 16 pages, 7 figure
Deciphering cosmological information from redshift surveys of high-z objects - the cosmological light-cone effect and redshift-space distortion -
The three-dimensional distribution of astronomical objects observed in
redshift space significantly differs from the true distribution since the
distance to each object cannot be determined by its redshift only; for the peculiar velocity field contaminates the true recession velocity of
the Hubble flow, while the true distance for objects at sensitively
depends on the (unknown and thus assumed) cosmological parameters. This hampers
the effort to understand the true distribution of large-scale structure of the
universe. In addition, all cosmological observations are carried out on a
light-cone, the null hypersurface of an observer at . This implies that
their intrinsic properties and clustering statistics should change even within
the survey volume. Therefore a proper comparison taking account of the
light-cone effect is important to extract any cosmological information from
redshift catalogues, especially for . We present recent theoretical
development on the two effects -- the cosmological light-cone effect and the
cosmological redshift-space distortion -- which should play key roles in
observational cosmology in the 21st century.Comment: 28pages, 20 figures, minor revision to match the final version to
appear in Progress of Theoretical Physics Supplement, vol. 133 (1999
Power Spectrum Analysis of the 2dF QSO Sample Revisited
We revisit the power spectrum analysis of the complete sample of the two
degree field (2dF) QSO redshift (2QZ) survey, as a complementary test of the
work by Outram et al. (2003). A power spectrum consistent with that of the 2QZ
group is obtained. Differently from their approach, fitting of the power
spectrum is investigated incorporating the nonlinear effects, the geometric
distortion and the light-cone effect. It is shown that the QSO power spectrum
is consistent with the cold dark matter (CDM) model with the matter
density parameter . Our constraint on the density
parameter is rather weaker than that of the 2QZ group. We also show that the
constraint slightly depends on the equation of state parameter of the dark
energy. The constraint on from the QSO power spectrum is demonstrated,
though it is not very tight.Comment: 15 pages, 5 figures, accepted for publication in the Astrophysical
Journa
Conditional transfer of quantum correlation in the intensity of twin beams
A conditional protocol of transferring quantum-correlation in continuous
variable regime was experimentally demonstrated. The quantum-correlation in two
pairs of twin beams, each characterized by intensity-difference squeezing of
7.0 dB, was transferred to two initially independent idler beams. The
quantum-correlation transfer resulted in intensity-difference squeezing of 4.0
dB between two idler beams. The dependence of preparation probability and
transfer fidellity on the selection bandwidth was also studied.Comment: 5 pages, submitte
Master Formula for the Three-Gluon Contribution to Single Spin Asymmetry in Semi-Inclusive Deep Inelastic Scattering
We derive a "master formula" for the contribution of the three-gluon
correlation function in the nucleon to the twist-3 single-spin-dependent cross
section for semi-inclusive deep-inelastic scattering, ep^\uparrow\to eDX. This
is an extension of the similar formula known for the so-called soft-gluon-pole
contribution induced by the quark-gluon correlation function in a variety of
processes. Our master formula reduces the relevant interfering partonic
subprocess with the participation of the three gluons to the Born cross
sections for the \gamma^*g\to c\bar{c} scattering, which reveals the new
structure behind the twist-3 single spin asymmetry and simplifies the actual
calculation greatly. A possible extension to higher order corrections is also
discussed.Comment: 23 pages, 4 figures. Final version to appear in Phys. Rev. D.
Presentation changed slightl
On the contribution of twist-3 multi-gluon correlation functions to single transverse-spin asymmetry in SIDIS
We study the single spin asymmetry (SSA) induced by purely gluonic
correlation inside a nucleon, in particular, by the three-gluon correlation
functions in the transversely polarized nucleon, . This
contribution is embodied as a twist-3 mechanism in the collinear factorization
framework and controls the SSA to be observed in the -meson production with
large transverse-momentum in semi-inclusive DIS (SIDIS), . We define the relevant three-gluon correlation functions in
the nucleon, and determine their complete set at the twsit-3 level taking into
account symmetry constraints in QCD. We derive the single-spin-dependent cross
section for the -meson production in SIDIS, taking into account all the
relevant contributions at the twist-3 level. The result is obtained in a
manifestly gauge-invariant form as the factorization formula in terms of the
three-gluon correlation functions and reveals the five independent structures
with respect to the dependence on the azimuthal angle for the produced
meson. We also demonstrate the remarkable relation between the twist-3
single-spin-dependent cross section and twist-2 cross sections for the
-meson production, as a manifestation of universal structure behind the SSA
in a variety of hard processes.Comment: 8 pages, 2 figures. To appear in the proceedings of the 19th
International Spin Physics Symposium (SPIN2010), Juelich, Germany, Sept.27 -
Oct.2, 201
Detection of Excess Hard X-ray Emission from the Group of Galaxies HCG62
From the group of galaxies HCG62, we detected an excess hard X-ray emission
in energies above keV with \A SCA. The excess emission is spatially
extended up to from the group center, and somewhat enhanced toward
north. Its spectrum can be represented by either a power-law of photon index
0.8-2.7, or a Bremsstrahlung of temperature keV. In the 2-10 keV range,
the observed hard X-ray flux, erg cm
s, implies a luminosity of erg s for a
Hubble constant of 50 km s Mpc. The emission is thus too luminous
to be attributed to X-ray binaries in the memb er galaxies. We discuss possible
origin of the hard X-ray emission.Comment: 6 pages, 3 Postscript figures, uses emulateapj.sty. Accepted for
publication in the Astrophysical Journal Letter
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