365 research outputs found

    Twist-3 Effects in Polarized Photon Structure

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    The polarized photon structure is described by two spin structure functions g1γg_1^\gamma and g2γg_2^\gamma which can be studied in the future polarized ep or e+^+e^- colliders. Here we investigate the QCD twist-3 effects in g2γg_2^\gamma to the leading order in QCD.Comment: 4 pages, LaTeX2e, 2 eps figures, ws-ijmpa.cls file included, Talk given at the 3rd Circum-Pan-Pacific Symposium on High Energy Spin Physics, Beijing, October 8-13, 2001, to appear in the Proceeding

    Increase of total alkalinity due to shoaling of aragonite saturation horizon in the Pacific and Indian Oceans: influence of anthropogenic carbon inputs

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    Aragonite Saturation Horizon (ASH) shallowed significantly by 25 to 155 m and 16 to 124 m in the Pacific and Indian Ocean respectively in two decades. Apparent Oxygen Utilization (AOU) increased by 3 to 34 and 0.5 to 31.5 μmol kg−1 in the Pacific and Indian Ocean respectively at the depth of ASH during this period. DIC increased by 12.5 to 36.8 and 5.5 to 32 μmol kg−1 in the vicinity of ASH in the Pacific and Indian Ocean respectively due to combined effect of increased anthropogenic CO2 and change in AOU. TA increased significantly by 5 to 10 and 4 to 9.2 μmol kg−1 in the Pacific and Indian Oceans respectively at the ASH most likely as a result of aragonite dissolution. The upward migration of ASH solely due to anthropogenic CO2 amounted to 6 to 58 m in the Pacific and 4 to 44 m in the Indian Ocean

    Target Mass Corrections for the Virtual Photon Structure Functions to the Next-to-next-to-leading Order in QCD

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    We investigate target mass effects in the unpolarized virtual photon structure functions F2γ(x,Q2,P2)F_2^\gamma(x,Q^2,P^2) and FLγ(x,Q2,P2)F_L^\gamma(x,Q^2,P^2) in perturbative QCD for the kinematical region Λ2P2Q2\Lambda^2 \ll P^2 \ll Q^2, where Q2(P2)-Q^2(-P^2) is the mass squared of the probe (target) photon and Λ\Lambda is the QCD scale parameter. We obtain the Nachtmann moments for the structure functions and then, by inverting the moments, we get the expressions in closed form for F2γ(x,Q2,P2)F_2^\gamma(x,Q^2,P^2) up to the next-to-next-to-leading order and for FLγ(x,Q2,P2)F_L^\gamma(x,Q^2,P^2) up to the next-to-leading order, both of which include the target mass corrections. Numerical analysis exhibits that target mass effects appear at large xx and become sizable near xmax(=1/(1+P2Q2))x_{\rm max}(=1/(1+\frac{P^2}{Q^2})), the maximal value of xx, as the ratio P2/Q2P^2/Q^2 increases.Comment: 24 pages, LaTeX, 7 eps figures, REVTeX

    The alphaalphas2alpha alpha_s^2 corrections to the first moment of the polarized virtual photon structure function g1gamma(x,Q2,P2)g_1^gamma(x,Q^2,P^2)

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    We present the next-to-next-to-leading order (alphaalphas2alpha alpha_s^2) corrections to the first moment of the polarized virtual photon structure function g1gamma(x,Q2,P2)g_1^gamma(x,Q^2,P^2) in the kinematical region Lambda2llP2llQ2Lambda^2 ll P^2 ll Q^2, where Q2(P2)-Q^2(-P^2) is the mass squared of the probe (target) photon and LambdaLambda is the QCD scale parameter. In order to evaluate the three-loop-level photon matrix element of the flavor singlet axial current, we resort to the Adler-Bardeen theorem for the axial anomaly and we calculate in effect the two-loop diagrams for the photon matrix element of the gluon operator. The alphaalphas2alpha alpha_s^2 corrections are found to be about 3% of the sum of the leading order (alphaalpha) andthe next-to-leading order (alphaalphasalpha alpha_s) contributions, when Q2=30sim100rmGeV2Q^2=30 sim 100 {rm GeV}^2and P2=3rmGeV2P^2=3{rm GeV}^2, and the number of active quark flavors nfn_f is three to five.Comment: 21 page

    Effective Monopole Action at Finite Temperature in SU(2) Gluodynamics

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    Effective monopole action at finite temperature in SU(2) gluodynamics is studied on anisotropic lattices. Using an inverse Monte-Carlo method and the blockspin transformation for space directions, we determine 4-dimensional effective monopole action at finite temperature. We get an almost perfect action in the continuum limit under the assumption that the action is composed of two-point interactions alone. It depends on a physical scale bsb_s and the temperature TT. The temperature-dependence appears with respect to the spacelike monopole couplings in the deconfinement phase, whereas the timelike monopole couplings do not show any appreciable temperature-dependence. The dimensional reduction of the 4-dimensional SU(2) gluodynamics ((SU(2))4D_{4D}) at high temperature is the 3-dimensional Georgi-Glashow model ((GG)3D(GG)_{3D}). The latter is studied at the parameter region obtained from the dimensional red uction. We compare the effective instanton action of (GG)3D(GG)_{3D} with the timelike monopole action obtained from (SU(2))4D_{4D}. We find that both agree very well for T2.4TcT \ge 2.4T_c at large bb region. The dimensional reduction works well also for the effective action.Comment: 34 pages, 23 figure

    Vacuum type of SU(2) gluodynamics in maximally Abelian and Landau gauges

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    The vacuum type of SU(2) gluodynamics is studied using Monte-Carlo simulations in maximally Abelian (MA) gauge and in Landau (LA) gauge, where the dual Meissner effect is observed to work. The dual Meissner effect is characterized by the coherence and the penetration lengths. Correlations between Wilson loops and electric fields are evaluated in order to measure the penetration length in both gauges. The coherence length is shown to be fixed in the MA gauge from measurements of the monopole density around the static quark-antiquark pair. It is also shown numerically that a dimension 2 gluon operator A^+A^-(s) and the monopole density has a strong correlation as suggested theoretically. Such a correlation is observed also between the monopole density and A^2(s)= A^+A^-(s) + A^3A^3(s) condensate if the remaining U(1) gauge degree of freedom is fixed to U(1) Landau gauge (U1LA). The coherence length is determined numerically also from correlations between Wilson loops and A^+A^-(s) and A^2(s) in MA + U1LA gauge. Assuming that the same physics works in the LA gauge, we determine the coherence length from correlations between Wilson loops and A^2(s). Penetration lengths and coherence lengths in the two gauges are almost the same. The vacuum type of the confinement phase in both gauges is near to the border between the type 1 and the type 2 dual superconductors.Comment: 13 pages, 22 figures, RevTeX 4 styl

    An Almost Perfect Quantum Lattice Action for Low-energy SU(2) Gluodynamics

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    We study various representations of infrared effective theory of SU(2) Gluodynamics as a (quantum) perfect lattice action. In particular we derive a monopole action and a string model of hadrons from SU(2) Gluodynamics. These are lattice actions which give almost cut-off independent physical quantities even on coarse lattices. The monopole action is determined by numerical simulations in the infrared region of SU(2) Gluodynamics. The string model of hadrons is derived from the monopole action by using BKT transformation. We illustrate the method and evaluate physical quantities such as the string tension and the mass of the lowest state of the glueball analytically using the string model of hadrons. It turns out that the classical results in the string model is near to the one in quantum SU(2) Gluodynamics.Comment: 39 pages, 10 figure

    Photocatalysis-induced selective decoration of semiconducting single walled carbon nanotubes: hole-doping effect

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    We have examined the time-dependent effect of the titanium oxide photocatalysis on N-methyl-2-pyrrolidone individually dispersed single walled carbon nanotube (SWNT) suspensions. From optical spectroscopic studies, we found a selective decoration of the semiconducting tubes. Such selectivity is attributed to the preferential attack of the photogenerated active species on the hole-doped semiconducting SWNTs.ArticleCHEMICAL COMMUNICATIONS. 46(37):6977-6979 (2010)journal articl

    Blocking of lattice monopoles from the continuum in hot lattice gluodynamics

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    The Abelian monopoles in lattice gluodynamics are associated with continuum monopoles blocked to the lattice. This association allows to predict the lattice monopole action and density of the (squared) monopole charges from a continuum monopole model. The method is applied to the static monopoles in high temperature gluodynamics. We show that the numerical data both for the density and the action of the lattice monopoles can be described in terms of a Coulomb gas of Abelian monopoles in the continuum.Comment: 23 pages, 9 EPS figures, LaTeX2e uses JHEP3 class file; replaced to match published versio

    Multiwavelength Monitoring of the BL Lacertae Object PKS 2155-304 in May 1994. II. The IUE Campaign

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    PKS 2155-304, the brightest BL Lac object in the ultraviolet sky, was monitored with the IUE satellite at ~1 hour time-resolution for ten nearly uninterrupted days in May 1994. The campaign, which was coordinated with EUVE, ROSAT, and ASCA monitoring, along with optical and radio observations from the ground, yielded the largest set of spectra and the richest short time scale variability information ever gathered for a blazar at UV wavelengths. The source flared dramatically during the first day, with an increase by a factor ~2.2 in an hour and a half. In subsequent days, the flux maintained a nearly constant level for ~5 days, then flared with ~35% amplitude for two days. The same variability was seen in both short- and long-wavelength IUE light curves, with zero formal lag (~<2 hr), except during the rapid initial flare, when the variations were not resolved. Spectral index variations were small and not clearly correlated with flux. The flux variability observed in the present monitoring is so rapid that for the first time, based on the UV emission alone, the traditional Delta L/Delta t limit indicating relativistic beaming is exceeded. The most rapid variations, under the likely assumption of synchrotron radiation, lead to a lower limit of 1 G on the magnetic field strength in the UV emitting region. These results are compared with earlier intensive monitoring of PKS 2155-304 with IUE in November 1991, when the UV flux variations had completely different characteristics.Comment: 45 pages, Latex, 11 PostScript figures, to appear in The Astrophysical Journa
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