The spectral problem for O(D) symmetric polynomial potentials allows for a partial algebraic solution after analytical continuation to negative even dimensions D. This fact is closely related to the...
Usually the asymptotic behavior for large orders of the perturbation theory is reached rather slowly. However, in the case of the N-component $\phi^4$ model in D=4 dimensions one can find a special...
Inequalities for Wilson loops, cusp singularities, area law and shape of a drum (2007)
Inequalities are derived for Wilson loops generalizing the well-known Bachas inequality for rectangular contours. The inequalities are compatible with the area law for large contours. The Polyakov...
Inequalities for nucleon generalized parton distributions with helicity flip (2005)
Kirch, M., Pobylitsa, P. V., Goeke, K.
Several positivity bounds are derived for generalized parton distributions (GPDs) with helicity flip.
Baryon wave function: Large-Nc QCD and lessons from models (2005)
The structure of the 1/Nc expansion for the baryon distribution amplitude in QCD is tested using quark models. Earlier conjectures about this structure based on the evolution equation and on the...
The 1/N_c expansion for the baryon distribution amplitude is constructed in terms of a specially designed generating functional. At large N_c this functional shows exponential behavior. The...
The 1/Nc expansion is formulated for the baryon wave function in terms of a specially constructed generating functional. The leading order of this 1/Nc expansion is universal for all low-lying...
Exotic baryons and the large-Nc expansion (2003)
The status of exotic baryons is analyzed in the limit of a large number of colors Nc. Several toy models reproducing the main features of the large-Nc QCD are studied in order to clarify the recent...
Lorentz invariance relations among parton distributions revisited (2003)
Goeke, K., Metz, A., Pobylitsa, P. V., Polyakov, M. V.
We revisit the derivation of the so-called Lorentz invariance relations between parton distributions. In the most important cases these relations involve twist-3 and transverse momentum dependent...
Transverse-momentum dependent parton distributions in large-Nc QCD (2003)
The transverse-momentum dependent quark distributions are studied in the limit of the large number of colors Nc. The leading orders of Nc are determined for all twist-2 distributions including the...
T-odd quark distributions: QCD versus chiral models (2002)
The T-odd quark distrbutions are shown to vanish in the chiral sigma model in contrast to the opposite widespread opinion. This failure of the chiral sigma model is a feature of the model itself and...
Spontaneously Broken Chiral Symmetry and Hard QCD Phenomena (2002)
Amarian, M. J., Braun, V. M., Brodsky, S. J., Collins, J., Diehl, M., Ecker, G., ...
These are the mini-proceedings of the workshop ``Spontaneously Broken Chiral Symmetry and Hard QCD Phenomena" held at the Physikzentrum Bad Honnef from July 15 to 19, 2002. Every author presents a...
The positivity bounds on generalized parton distributions are derived from the positivity properties of the absorptive part of the amplitude of the virtual Compton scattering in the generalized...
Integral representations for nonperturbative GPDs in terms of perturbative diagrams (2002)
An integral representation is suggested for generalized parton distributions which automatically satisfies the polynomiality and positivity constraints. This representation has the form of an...
Solution of polynomiality and positivity constraints on generalized parton distributions (2002)
An integral representation for generalized parton distributions of spin-0 hadrons is suggested, which satisfies both polynomiality and positivity constraints.
Positivity bounds on generalized parton distributions in impact parameter representation (2002)
New positivity bounds are derived for generalized (off-forward) parton distributions using the impact parameter representation. These inequalities are stable under the evolution to higher...
Positivity bounds on parton distributions at large N_c (2002)
Positivity bounds for twist-two parton distributions in multicolored QCD are stronger than their analogs at finite $N_c$. They include the enhanced large $N_{c}$ version of Soffer inequality. These...
Disentangling positivity constraints for generalized parton distributions (2002)
Positivity constraints are derived for the generalized parton distributions (GPDs) of spin-1/2 hadrons. The analysis covers the full set of eight twist-2 GPDs. Several new inequalities are obtained...
Inequalities for generalized parton distributions H and E (2001)
New positivity bounds are derived for quark and gluon generalized parton distributions $H$ and $E$ in spin 1/2 hadrons.
Transversity distributions in the nucleon in the large-N_c limit (2001)
Schweitzer, P., Urbano, D., Polyakov, M. V., Weiss, C., Pobylitsa, P. V., Goeke, K.
We compute the quark and antiquark transversity distributions in the nucleon at a low normalization point of 600 MeV in the large-$N_c$ limit, where the nucleon can be described as a soliton of an...
Soft pion theorem for hard near threshold pion production (2001)
Pobylitsa, P. V., Polyakov, M. V., Strikman, M.
We prove new soft pion theorem for the near threshold pion production by a hard electromagnetic probe. This theorem relates various near threshold pion production amplitudes to the nucleon...
Meson twist-4 parton distributions in terms of twist-2 distribution amplitudes at large Nc (2000)
Pobylitsa, P. V., Polyakov, M. V., Goeke, K.
We show that in the large N_c limit four-quark twist-4 distributions in the pion can be expressed in terms of twist-2 pion distribution amplitude. This allows us to compute the isospin-2 structure...
Gluon and quark distributions in large N_c QCD: theory vs. phenomenology (2000)
Efremov, A. V., Goeke, K., Pobylitsa, P. V.
We present the QCD analysis of the behavior of quark and gluon distributions in the limit of a large number of colors N_c. We show that the results agree qualitatively with the phenomenological data....
New positivity bounds on polarized parton distributions in multicolored QCD (2000)
Pobylitsa, P. V., Polyakov, M. V.
We derive new positivity bounds on spin-dependent parton distributions in multicolored QCD. They are stronger than Soffer inequality. We check that the new inequalities are stable under one-loop...
Polarized antiquark distributions from chiral quark-soliton model: summary of the results (2000)
Goeke, K., Pobylitsa, P. V., Polyakov, M. V., Urbano, D.
In these short notes we present a parametrization of the results obtained in the chiral quark-soliton model for polarized antiquark distributions $\Delta\bar u$, $\Delta\bar d$ and $\Delta\bar s$ at...
Goeke, K., Pobylitsa, P. V., Polyakov, M. V., Schweitzer, P., Urbano, D.
In the framework of the chiral quark-soliton model of the nucleon we investigate the properties of the polarized quark distribution. In particular we analyse the so called anomalous difference...
Hard diffractive electroproduction of two pions (1999)
Lehmann-Dronke, B., Pobylitsa, P. V., Polyakov, M. V., Schafer, A., Goeke, K.
We have calculated the leading order amplitude of hard diffractive electroproduction of two pions in lepton nucleon scattering. At the leading twist level a pion pair can be produced only in an...
Hard exclusive pseudoscalar meson electroproduction and spin structure of a nucleon (1999)
Frankfurt, L. L., Pobylitsa, P. V., Polyakov, M. V., Strikman, M.
The amplitude for hard exclusive pseudoscalar meson electroproduction off nucleon (nuclear) targets is computed in QCD within the leading $\alpha_s \ln {Q^2/\lambda_{QCD}^{2}}$ approximation. We show...
Franz, M., Pobylitsa, P. V., Polyakov, M. V., Goeke, K.
Recently in the context of studies of the intrinsic charm content of the nucleon and of the eta' meson two groups have arrived at different results for the 1/m^3 term of the heavy quark expansion for...
Flavor asymmetry of polarized and unpolarized sea quark distributions in the large-N_c limit (1998)
Dressler, B., Goeke, K., Pobylitsa, P. V., Polyakov, M. V., Watabe, T., Weiss, C.
We summarize recent attempts to calculate the flavor asymmetry of the nucleon's sea quark distributions in the large-$N_c$ limit, where the nucleon can be described as a soliton of an effective...
Unpolarized and Polarized Quark Distributions in the (1998)
V. Yu. Petrov, P. V. Pobylitsa, M. V. Polyakov, C. Weiss
The isosinglet unpolarized and isovector polarized twist--2 quark distributions of the nucleon at low normalization point are calculated in the large--N c limit. The nucleon is described as a soliton...
Isovector unpolarized quark distribution in the nucleon in the large-N_c limit (1998)
Pobylitsa, P. V., Polyakov, M. V., Goeke, K., Watabe, T., Weiss, C.
We calculate the isovector (flavor-nonsinglet) unpolarized quark- and antiquark distributions in the nucleon at a low normalization point in the large-N_c limit. The nucleon is described as a soliton...
Unpolarized and Polarized Quark Distributions in the (1997)
V. Yu. Petrov, P. V. Pobylitsa, M. V. Polyakov, C. Weiss
The isosinglet unpolarized and isovector polarized twist--2 quark distributions of the nucleon at low normalization point are calculated in the large--N c limit. The nucleon is described as a soliton...
Unpolarized and Polarized Quark Distributions in the (1997)
V. Yu. Petrov, P. V. Pobylitsa, M. V. Polyakov, C. Weiss
The isosinglet unpolarized and isovector polarized twist--2 quark distributions of the nucleon at low normalization point are calculated in the large--N c limit. The nucleon is described as a soliton...
Pion wave function from the instanton vacuum model (1997)
Petrov, V. Yu., Pobylitsa, P. V.
The pion wave function is computed in the low energy effective theory inspired by the instanton vacuum model. The resultat is numerically rather close to the asymptotical wave function.
Off-forward quark distributions of the nucleon in the large N_c limit (1997)
Petrov, V. Yu., Pobylitsa, P. V., Polyakov, M. V., Boernig, I., Goeke, K., Weiss, C.
We study the off-forward quark distributions (OFQD's) in the chiral quark-soliton model of the nucleon. This model is based on the large-N_c picture of the nucleon as a soliton of the effective...
Unpolarized and polarized quark distributions in the large-Nc limit (1997)
Diakonov, D. I., Petrov, V. Yu., Pobylitsa, P. V., Polyakov, M. V., Weiss, C.
The isosinglet unpolarized and isovector polarized twist-2 quark distributions of the nucleon at low normalization point are calculated in the large-Nc limit. The nucleon is described as a soliton of...
Transverse Spin Distribution Function of Nucleon in Chiral Theory (1996)
Pobylitsa, P. V., Polyakov, M. V.
At large N_c the nucleon can be viewed as a soliton of the effective chiral lagrangian. This picture of nucleons allows a consistent nonperturbative calculation of the leading-twist parton...
Electromagnetic form factors of the nucleon in the chiral quark soliton model (1995)
Christov, Chr. V., Górski, A. Z., Goeke, K., Pobylitsa, P. V.
In this paper we present the derivation as well as the numerical results for the electromagnetic form factors of the nucleon within the chiral quark soliton model in the semiclassical quantization...
$1/N_c$ Rotational Corrections to $g_A$ in the NJL Model and Charge Conjugation (1994)
Christov, Chr. V., Goeke, K., Pobylitsa, P. V.
We show that the $1/N_c$ rotational corrections to $g_A$, derived using the semiclassical quantization scheme in the NJL model, possess correct properties under charge conjugation.
Electromagnetic Nucleon Properties and Quark Sea Polarization (1994)
Christov, Chr. V., Górski, A. Z., Goeke, K., Pobylitsa, P. V.
In this paper we present the derivation as well as the numerical results for all electromagnetic form factors of the nucleon within the chiral quark soliton model in the semiclassical quantization...