334 research outputs found
Elements of a field theory of unitarity corrections
I explain the motivation for investigating the high energy limit of QCD and
give a brief presentation of recent progress in the understanding of unitarity
corrections in this kinematic regime. Special emphasis is given to the
conformal field theory structure discovered in these unitarity corrections.Comment: 4 pages, Talk presented at 7th International Workshop on Deep
Inelastic Scattering, Zeuthen, Germany, April 199
Generalized Coordinate Gauge, Nonabelian Stokes Theorem and Dual QCD Lagrangian
This paper is an extended version of hep-th/9802134. Dual QCD Lagrangian is
derived by making use of the generalized coordinate gauge, where 1-form (vector
potential) is expressed as an integral of the 2-form (field strength) along an
(arbitrary) contour. As another application a simple proof of the nonabelian
Stokes theorem is given.Comment: LaTeX 13 pages, no figure
Unitarization of Total Cross Section and Coherent Effect in pQCD
A formula to unitarize the leading-log BFKL-Pomeron amplitude is derived
using a coherent property of two-body collision in the peripheral region. This
procedure also allows an algebraic characterization of the Reggeon in QCD based
on color, instead of the total angular momentum of the gluons being exchanged.Comment: Talk given at the DIS99 Meeting in Zeuthen, Germany. April, 1999. 3
page
Estimates of higher-dimensional vacuum condensates from the instanton vacuum
We calculate the values of non-factorizable dimension-7 vacuum condensates in
the instanton vacuum. We comment on a method, recently proposed by Oganesian,
to estimate the dimension-7 condensates by factorization of dimension-10
condensates in various inequivalent ways. The instanton estimates could be used
to analyze the stability of QCD sum rules with increasing dimensions.Comment: 8 pages, Late
Influence of working environments on fatigue crack propagation in high nitrogen steels
The characteristic parameters dependence under cyclic deformation in hydrogen,
chloride environments and the subsequent selective dissolution has been studied. For high
nitrogen steels and welded joints it has been established that mechanical stresses accelerate
general dissolution of an alloy in different ways and lead to the formation of a surface layer
morphology which is different from the original one. Welded joints characterized by a higher
corrosion fatigue resistance in all investigated solutions, except saturated cupper chloride
solution
Strong Bootstrap Conditions
We reformulate the so-called ``strong bootstrap'' conditions for the gluon
Reggeization in the next-to-leading approximation (NLA), firstly suggested by
Braun and Vacca, using a different approach, which is not based on properties
of the eigenstates of the NLA octet BFKL kernel. We write the second strong
bootstrap condition for the NLA octet impact factors in a form which makes
clear their dependence on the process. According to this condition, the NLA
octet impact factors must be given by the product of the corresponding Reggeon
interaction vertices with a universal coefficient function. This function can
be used also in the formulation of the first strong bootstrap condition for the
NLA BFKL kernel in the octet state.Comment: 10 page
Baryon stopping and saturation physics in relativistic collisions
We investigate baryon transport in relativistic heavy-ion collisions at
energies reached at the CERN Super Proton Synchrotron, BNL Relativistic
Heavy-Ion Collider (RHIC), and CERN LHC in the model of saturation. An
analytical scaling law is derived within the color glass condensate framework
based on small-coupling QCD. Transverse momentum spectra, net-baryon rapidity
distributions and their energy, mass and centrality dependences are well
described. In a comparison with RHIC data in Au + Au collisions at sqrt (s_NN)
= 62.4 GeV and 200 GeV, the gradual approach to the gluon saturation regime is
investigated, and limits for the saturation-scale exponent are determined.
Predictions for net-baryon rapidity spectra and the mean rapidity loss in
central Pb + Pb collisions at LHC energies of sqrt (s_NN) = 5.52 TeV are made.Comment: 11 pages, 10 Figures; improved figure inscriptions, corrected typos,
minor changes in text/titl
Baryon Stopping as a new Probe of Geometric Scaling
We suggest to use net-baryon rapidity distributions in central relativistic
heavy-ion collisions at SPS, RHIC and LHC energies in order to probe saturation
physics. Within the color glass condensate framework based on small-coupling
QCD, net-baryon rapidity distributions are shown to exhibit geometric scaling.
In a comparison with RHIC data in Au + Au collisions at sqrt(s_NN) = 62.4 GeV
and 200 GeV the gradual approach to the gluon saturation regime is
investigated. Predictions for net-baryon rapidity spectra and the mean rapidity
loss in central Pb + Pb collisions at LHC energies of sqrt (s_NN) = 5.5 TeV are
made.Comment: 4 pages 3 figures; calculation and figures now for net baryons
instead of net protons; modified conclusion
Running Coupling BFKL Equation and Deep Inelastic Scattering
I examine the form of the solution of the BFKL equation with running coupling
relevant for deep inelastic scattering. The evolution of structure functions is
precisely determined and well described by an effective coupling of the form
1/(beta_0(ln(Q^2/Lambda^2)+3.6(alpha_s(Q^2)ln(1/x))^1/2)) (until very small x).
Corrections to the LO equation are relatively small, and the perturbative
expansion is stable. Comparison to data via a global fit is very successful.Comment: Latex file uses epsfig.sty and npb.sty, 4 pages including 1 embedded
figure. Contribution to the proceedings of the International Workshop on Deep
Inelastic Scattering and QCD (DIS99), Zeuthen, April 199
Modular Invariance and the Odderon
We identify a new symmetry for the equations governing odderon amplitudes,
corresponding in the Regge limit of QCD to the exchange of 3 reggeized gluons.
The symmetry is a modular invariance with respect to the unique normal subgroup
of sl(2,Z) {\,} of index 2.
This leads to a natural description of the Hamiltonian and conservation-law
operators as acting on the moduli space of elliptic curves with a fixed
``sign'': elliptic curves are identified if they can be transformed into each
other by an {\em even} number of Dehn twists.Comment: 9 pages, LaTeX, uses amssym.def for \Bbb 'blackboard math' font
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