1,695 research outputs found

    Single Transverse-Spin Asymmetry in Large PTP_T Open Charm Production at an Electron-Ion Collider

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    We discuss the single transverse-spin asymmetry (SSA) to be observed in the DD-meson production with large transverse-momentum in semi-inclusive deep inelastic scattering, epeDXe p^\uparrow \rightarrow e D X. 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 DD-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 -

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    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 zz only; for z1z \ll 1 the peculiar velocity field contaminates the true recession velocity of the Hubble flow, while the true distance for objects at z<1z < 1 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 z=0z=0. 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 z<1z < 1. 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

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    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 Λ\Lambda cold dark matter (CDM) model with the matter density parameter Ωm=0.20.5\Omega_m=0.2\sim0.5. 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 ww of the dark energy. The constraint on ww 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

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    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

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    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

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    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, pp^\uparrow. This contribution is embodied as a twist-3 mechanism in the collinear factorization framework and controls the SSA to be observed in the DD-meson production with large transverse-momentum in semi-inclusive DIS (SIDIS), epeDXep^\uparrow \rightarrow eDX. 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 DD-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 DD meson. We also demonstrate the remarkable relation between the twist-3 single-spin-dependent cross section and twist-2 cross sections for the DD-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

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    From the group of galaxies HCG62, we detected an excess hard X-ray emission in energies above 4\sim 4 keV with \A SCA. The excess emission is spatially extended up to 10\sim10' 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 >6.3>6.3 keV. In the 2-10 keV range, the observed hard X-ray flux, (1.0±0.3)×1012(1.0\pm0.3)\times10^{-12} erg cm2^{-2} s1^{-1}, implies a luminosity of (8.0±2.0)×1041(8.0\pm2.0)\times10^{41} erg s1^{-1} for a Hubble constant of 50 km s1^{-1} Mpc1^{-1}. 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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