203 research outputs found
Spin Structure Function of the Virtual Photon Beyond the Leading Order in QCD
Polarized photon structure can be studied in the future polarized
colliding-beam experiments. We investigate the spin-dependent
structure function of the virtual photon , in
perturbative QCD for , where () is the
mass squared of the probe (target) photon. The analysis is performed to
next-to-leading order in QCD. We particularly emphasize the renormalization
scheme independence of the result.The non-leading corrections significantly
modify the leading log result, in particular, at large as well as at small
. We also discuss the non-vanishing first moment sum rule of ,
where corrections are computed.Comment: 39 pages, LaTeX, 6 Postscript Figures, eqsection.sty file include
Blocking of lattice monopoles from the continuum in hot lattice gluodynamics
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
Differential Calculus on the Quantum Superspace and Deformation of Phase Space
We investigate non-commutative differential calculus on the supersymmetric
version of quantum space where the non-commuting super-coordinates consist of
bosonic as well as fermionic (Grassmann) coordinates. Multi-parametric quantum
deformation of the general linear supergroup, , is studied and the
explicit form for the -matrix, which is the solution of the
Yang-Baxter equation, is presented. We derive the quantum-matrix commutation
relation of and the quantum superdeterminant. We apply these
results for the to the deformed phase-space of supercoordinates and
their momenta, from which we construct the -matrix of q-deformed
orthosymplectic group and calculate its -matrix. Some
detailed argument for quantum super-Clifford algebras and the explict
expression of the -matrix will be presented for the case of
.Comment: 17 pages, KUCP-4
Multiwavelength Monitoring of the BL Lacertae Object PKS 2155-304 in May 1994. II. The IUE Campaign
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
Virtual photon structure functions and positivity constraints
We study the three positivity constraints among the eight virtual photon
structure functions, derived from the Cauchy-Schwarz inequality and which are
hence model-independent. The photon structure functions obtained from the
simple parton model show quite different behaviors in a massive quark or a
massless quark case, but they satisfy, in both cases, the three positivity
constraints. We then discuss an inequality which holds among the unpolarized
and polarized photon structure functions , and
, in the kinematic region , where is the mass squared of the probe (target) photon, and we examine
whether this inequality is satisfied by the perturbative QCD results.Comment: 24 pages, 13 eps figure
Atmospheric observations suggest methane emissions in north-eastern China growing with natural gas use
The dramatic increase of natural gas use in China, as a substitute for coal, helps to reduce CO2 emissions and air pollution, but the climate mitigation benefit can be offset by methane leakage into the atmosphere. We estimate methane emissions from 2010 to 2018 in four regions of China using the GOSAT satellite data and in-situ observations with a high-resolution (0.1 degrees x 0.1 degrees) inverse model and analyze interannual changes of emissions by source sectors. We find that estimated methane emission over the north-eastern China region contributes the largest part (0.77 Tg CH4 yr(-1)) of the methane emission growth rate of China (0.87 Tg CH4 yr(-1)) and is largely attributable to the growth in natural gas use. The results provide evidence of a detectable impact on atmospheric methane observations by the increasing natural gas use in China and call for methane emission reductions throughout the gas supply chain and promotion of low emission end-use facilities.Peer reviewe
Interannual variability on methane emissions in monsoon Asia derived from GOSAT and surface observations
In Asia, much effort is put into reducing methane (CH4) emissions due to the region's contribution to the recent rapid global atmospheric CH4 concentration growth. Accurate quantification of Asia's CH4 budgets is critical for conducting global stocktake and achieving the long-term temperature goal of the Paris Agreement. In this study, we present top-down estimates of CH4 emissions from 2009 to 2018 deduced from atmospheric observations from surface network and GOSAT satellite with the high-resolution global inverse model NIES-TM-FLEXPART-VAR. The optimized average CH4 budgets are 63.40 +/- 10.52 Tg y(-1) from East Asia (EA), 45.20 +/- 6.22 Tg y(-1) from Southeast Asia (SEA), and 64.35 +/- 9.28 Tg y(-1) from South Asia (SA) within the 10 years. We analyzed two 5 years CH4 emission budgets for three subregions and 13 top-emitting countries with an emission budget larger than 1 Tg y(-1), and interannual variabilities for these subregions. Statistically significant increasing trends in emissions are found in EA with a lower emission growth rate during 2014-2018 compared to that during 2009-2013, while trends in SEA are not significant. In contrast to the prior emission, the posterior emission shows a significant decreasing trend in SA. The flux decrease is associated with the transition from strong La Ninna (2010-2011) to strong El Ninno (2015-2016) events, which modulate the surface air temperature and rainfall patterns. The interannual variability in CH4 flux anomalies was larger in SA compared to EA and SEA. The Southern Oscillation Index correlates strongly with interannual CH4 flux anomalies for SA. Our findings suggest that the interannual variability in the total CH4 flux is dominated by climate variability in SA. The contribution of climate variability driving interannual variability in natural and anthropogenic CH4 emissions should be further quantified, especially for tropical countries. Accounting for climate variability may be necessary to improve anthropogenic emission inventories.Peer reviewe
Parton distributions in the virtual photon target up to NNLO in QCD
Parton distributions in the virtual photon target are investigated in
perturbative QCD up to the next-to-next-to-leading order (NNLO). In the case
, where () is the mass squared of the
probe (target) photon, parton distributions can be predicted completely up to
the NNLO, but they are factorisation-scheme-dependent. We analyse parton
distributions in two different factorisation schemes, namely and
schemes, and discuss their scheme dependence. We show that
the factorisation-scheme dependence is characterised by the large-
behaviours of quark distributions. Gluon distribution is predicted to be very
small in absolute value except in the small- region.Comment: 28 pages, 5 figures, version to appear in Eur. Phys. J.
An Almost Perfect Quantum Lattice Action for Low-energy SU(2) Gluodynamics
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
Methane Emission Estimates by the Global High-Resolution Inverse Model Using National Inventories
We present a global 0.1° Ă 0.1° high-resolution inverse model, NIES-TM-FLEXPART-VAR (NTFVAR), and a methane emission evaluation using the Greenhouse Gas Observing Satellite (GOSAT) satellite and ground-based observations from 2010â2012. Prior fluxes contained two variants of anthropogenic emissions, Emissions Database for Global Atmospheric Research (EDGAR) v4.3.2 and adjusted EDGAR v4.3.2 which were scaled to match the country totals by national reports to the United Nations Framework Convention on Climate Change (UNFCCC), augmented by biomass burning emissions from Global Fire Assimilation System (GFASv1.2) and wetlands Vegetation Integrative Simulator for Trace Gases (VISIT). The ratio of the UNFCCC-adjusted global anthropogenic emissions to EDGAR is 98%. This varies by region: 200% in Russia, 84% in China, and 62% in India. By changing prior emissions from EDGAR to UNFCCC-adjusted values, the optimized total emissions increased from 36.2 to 46 Tg CH4 yrâ1 for Russia, 12.8 to 14.3 Tg CH4 yrâ1 for temperate South America, and 43.2 to 44.9 Tg CH4 yrâ1 for contiguous USA, and the values decrease from 54 to 51.3 Tg CH4 yrâ1 for China, 26.2 to 25.5 Tg CH4 yrâ1 for Europe, and by 12.4 Tg CH4 yrâ1 for India. The use of the national report to scale EDGAR emissions allows more detailed statistical data and country-specific emission factors to be gathered in place compared to those available for EDGAR inventory. This serves policy needs by evaluating the national or regional emission totals reported to the UNFCCC
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