Generalized parton correlation functions for a spin-1/2 hadron

The fully unintegrated, off-diagonal quark-quark correlator for a spin-1/2 hadron is parameterized in terms of so-called generalized parton correlation functions. Such objects, in particular, can be considered as mother distributions of generalized parton distributions on the one hand and transverse momentum dependent parton distributions on the other. Therefore, our study provides new, model-independent insights into the recently proposed nontrivial relations between generalized and transverse momentum dependent parton distributions. We find that none of these relations can be promoted to a model-independent status. As a by-product we obtain the first complete classification of generalized parton distributions beyond leading twist. The present paper is a natural extension of our previous corresponding analysis for spin-0 hadrons.Comment: 41 pages, 3 figures; v2: added referenc

Predictions for dijet production in DIS using small x dynamics

We study the properties of dijet production in deep inelastic scattering using a unified BFKL/DGLAP framework, which includes important subleading ln (1/x) contributions. We calculate the azimuthal decorrelation between the jets. We compute the cross section for dijet production as a function of Q^2 and the jet transverse momentum, as well as calculate the total dijet rate. We compare the predictions with HERA data.Comment: 7 pages, LaTeX with 4 eps figure

BFKL predictions at small x from k_T and collinear factorization viewpoints

Hard scattering processes involving hadrons at small $x$ are described by a $k_T$-factorization formula driven by a BFKL gluon. We explore the equivalence of this description to a collinear-factorization approach in which the anomalous dimensions $\gamma_{gg}$ and $\gamma_{qg}/\alpha_S$ are expressed as power series in $\alpha_S \log (1/x)$, or to be precise $\alpha_S/\omega$ where $\omega$ is the moment index. In particular we confront the collinear-factorization expansion with that extracted from the BFKL approach with running coupling included.Comment: 11 LaTeX pages, 1 figure (uuencoded

Future non-linear stability for reflection symmetric solutions of the Einstein-Vlasov system of Bianchi types II and VI0_0

Using the methods developed for the Bianchi I case we have shown that a boostrap argument is also suitable to treat the future non-linear stability for reflection symmetric solutions of the Einstein-Vlasov system of Bianchi types II and VI$_0$. These solutions are asymptotic to the Collins-Stewart solution with dust and the Ellis-MacCallum solution respectively. We have thus generalized the results obtained by Rendall and Uggla in the case of locally rotationally symmetric Bianchi II spacetimes to the reflection symmetric case. However we needed to assume small data. For Bianchi VI$_0$ there is no analogous previous result.Comment: 30 page

Diffractive parton distributions from H1 data

We analyse the latest H1 large rapidity gap data to obtain diffractive parton distributions, using a procedure based on perturbative QCD, and compare them with distributions obtained from the simplified Regge factorisation type of analysis. The diffractive parton densities and structure functions are made publically available.Comment: 9 pages, 2 figures. Fortran code for diffractive parton densities and structure functions can be found at http://durpdg.dur.ac.uk/hepdata/mrw.html . Version to appear in Phys. Lett. B; final paragraph added, with curves from H1 incl.+dijet fit added to Fig.

NLO prescription for unintegrated parton distributions

We show how parton distributions unintegrated over the parton transverse momentum, k_t, may be generated, at NLO accuracy, from the known integrated (DGLAP-evolved) parton densities determined from global data analyses. A few numerical examples are given, which demonstrate that sufficient accuracy is obtained by keeping only the LO splitting functions together with the NLO integrated parton densities. However, it is important to keep the precise kinematics of the process, by taking the scale to be the virtuality rather than the transverse momentum, in order to be consistent with the calculation of the NLO splitting functions.Comment: 20 pages, 8 figures. v2: version to appear in Eur. Phys. J.

From the Big Bang Theory to the Theory of a Stationary Universe

We consider chaotic inflation in the theories with the effective potentials phi^n and e^{\alpha\phi}. In such theories inflationary domains containing sufficiently large and homogeneous scalar field \phi permanently produce new inflationary domains of a similar type. We show that under certain conditions this process of the self-reproduction of the Universe can be described by a stationary distribution of probability, which means that the fraction of the physical volume of the Universe in a state with given properties (with given values of fields, with a given density of matter, etc.) does not depend on time, both at the stage of inflation and after it. This represents a strong deviation of inflationary cosmology from the standard Big Bang paradigm. We compare our approach with other approaches to quantum cosmology, and illustrate some of the general conclusions mentioned above with the results of a computer simulation of stochastic processes in the inflationary Universe.Comment: No changes to the file, but original figures are included. They substantially help to understand this paper, as well as eternal inflation in general, and what is now called the "multiverse" and the "string theory landscape." High quality figures can be found at http://www.stanford.edu/~alinde/LLMbigfigs

On the parabolic equation method in internal wave propagation

A parabolic equation for the propagation of periodic internal waves over varying bottom topography is derived using the multiple-scale perturbation method. Some computational aspects of the numerical implementation are discussed. The results of numerical experiments on propagation of an incident plane wave over a circular-type shoal are presented in comparison with the analytical result, based on Born approximation.Comment: Submitted to Coastal Engineering. 16 pages, 5 figures. One figure was excluded from article because of size problem

Properties of the BFKL equation and structure function predictions for HERA

The general properties of the Lipatov or BFKL equation are reviewed. Modifications to the infrared region are proposed. Numerical predictions for the deep-inelastic electron-proton structure functions at small $x$ are presented and confronted with recent HERA measurements.Comment: 21 pages, 11 figures, Latex file, Durham preprint DTP 92/2

Implications of Scaling Violations of F2 at HERA for Perturbative QCD

We critically examine the QCD predictions for the $Q^2$ dependence of the electron-proton deep-inelastic structure function $F_2(x,Q^2)$ in the small $x$ region, which is being probed at HERA. The standard results based on next-to-leading order Altarelli-Parisi evolution are compared with those that follow from the BFKL equation, which corresponds to the resummation of the leading log$(1/x)$ terms. The effects of parton screening are also quantified. The theoretical predictions are confronted with each other, and with existing data from HERA. (3 Postscript figures included).Comment: (8 Latex Pages) IFJ 1653/P