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S. Srednyak

Publications and source records attributed to S. Srednyak.

6 recordsLinked to original sources

Flat Bundles on Function Manifolds and Evolution Equations in Quantum Field Theories

In this paper we discuss extensions of the canonical quantization procedure in quantum field theories. We focus specifically on S-matrix representation as a T-exponent. This extension involves flat bundles on certain infinite dimensional functional manifolds of local time. The motivating problem is first principles treatment of bound states in quantum chromodynamics as well as precision physics of hydrogen atom and the muonium. Our main results include systematic treatment of flat bundles in an infinite dimensional setting, generalization of Hamiltonian evolution and functional renormalization group evolution equations in quantum field theories. We discuss several results from finite dimensional theory that have analogies in the functional setting. This includes construction of moduli space of flat connections and isomonodromic deformations. One of the outcomes of our analysis is a construction of a rich family of functional flat bundles with rational connections. This class of connections exhibits a rich set of mathematical properties. In particular, we construct examples of spaces fundamental groups of which have a definable continuum of generators. Physical states correspond to points in the moduli space of bundles on these spaces. On the physics side of things, we conclude that spacetime notions, such as spaces of particle configurations, emerge effectively as spectral sets of functional differential operators.

physics.gen-ph

Complete lowest order radiative corrections in semi-inclusive scattering of polarized particles

The lowest order radiative corrections to the cross section and asymmetries measured in experiments on semi-inclusive deep inelastic scattering of polarized particles were calculated. Both exact and leading log expressions were presented and discussed for the total correction that include the contributions from the processes of (i) real photon emission with semi-inclusive processes, (ii) loop diagrams, and (iii) real photon emission with exclusive processes. Radiative corrections to the Sivers and Collins asymmetries in $π^+$ electroproduction were studied numerically within the kinematical conditions of modern experimental environments at Jefferson Laboratory (JLab). The Wandzura-Wilczek approximation for the semi-inclusive structure functions and MAID2007 parameterization for the six amplitudes of exclusive processes were used in numeric analyses. The results show that (i) radiative effects can generate a correction comparable to the size of Sivers and Collins asymmetries at the Born level, (ii) there is good agreement between the exact and leading-order corrections, (iii) external functions (that is, other than the Sivers and Collins functions in the respective asymmetries) can generate a contribution to the radiative correction up to 20\%, and (iv) there exists a strong dependence of the radiative correction on the models for semi-inclusive and exclusive structure functions.

hep-ph

Structure of vertices in massless theories

We characterize the singularity set of massless theories by giving a complete set of the Landau polynomials. We find the general form of Gauss-Manin connection. We show that for massless theories the dependence on momenta decouples from the dependence on coupling and dimension. The latter is completely absorbed into a set of matrices that have no dependence on kinematic variables.

hep-th

Reduction of Feynman integrals to integrals of Schläfli functions

We show that off-shell perturbative amplitudes with arbitrary number of external lines and complex masses can be reduced to $I$-fold integrals of the generalized Schläfli functions, where $I$ is the number of lines in the corresponding vacuum diagram which is independent of the number of external lines. The Schläfli functions are obtained as analytic continuation of the volume of the spherical simplex as a function of the hyperplane parameters that define the simplex. These functions have nice and thoroughly studied analytic, geometric and number theoretic properties. They possess Gauss-Manin connection and in conformal case are expressed by iterated integrals. Our representation sheds new light on geometry of particle configuration spaces in perturbation theory.

hep-ph

Non-perturbative computation of double inclusive gluon production in the Glasma

The near-side ridge observed in A+A collisions at RHIC has been described as arising from the radial flow of Glasma flux tubes formed at very early times in the collisions. We investigate the viability of this scenario by performing a non-perturbative numerical computation of double inclusive gluon production in the Glasma. Our results support the conjecture that the range of transverse color screening of correlations determining the size of the flux tubes is a semi-hard scale, albeit with non-trivial structure. We discuss our results in the context of ridge correlations in the RHIC heavy ion experiments.

hep-ph