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V. Pauk

Publications and source records attributed to V. Pauk.

6 recordsLinked to original sources
arXiv2019

Determination of the pole position of the lightest hybrid meson candidate

Mapping states with explicit gluonic degrees of freedom in the light sector is a challenge, and has led to controversies in the past. In particular, the experiments have reported two different hybrid candidates with spin-exotic signature, pi1(1400) and pi1(1600), which couple separately to eta pi and eta' pi. This picture is not compatible with recent Lattice QCD estimates for hybrid states, nor with most phenomenological models. We consider the recent partial wave analysis of the eta(') pi system by the COMPASS collaboration. We fit the extracted intensities and phases with a coupled-channel amplitude that enforces the unitarity and analyticity of the S-matrix. We provide a robust extraction of a single exotic pi1 resonant pole, with mass and width 1564 +- 24 +- 86 MeV and 492 +- 54 +- 102 MeV, which couples to both eta(') pi channels. We find no evidence for a second exotic state. We also provide the resonance parameters of the a2(1320) and a2'(1700).

hep-ph↗
arXiv2017

Analyticity Constraints for Hadron Amplitudes: Going High to Heal Low Energy Issues

Analyticity constitutes a rigid constraint on hadron scattering amplitudes. This property is used to relate models in different energy regimes. Using meson photoproduction as a benchmark, we show how to test contemporary low energy models directly against high energy data. This method pinpoints deficiencies of the models and treads a path to further improvement. The implementation of this technique enables one to produce more stable and reliable partial waves for future use in hadron spectroscopy and new physics searches.

hep-ph↗
arXiv2017

New analysis of $ηπ$ tensor resonances measured at the COMPASS experiment

We present a new amplitude analysis of the $ηπ$ $D$-wave in $π^- p\to ηπ^- p$ measured by COMPASS. Employing an analytical model based on the principles of the relativistic $S$-matrix, we find two resonances that can be identified with the $a_2(1320)$ and the excited $a_2^\prime(1700)$, and perform a comprehensive analysis of their pole positions. For the mass and width of the $a_2$ we find $M=(1307 \pm 1 \pm 6)$~MeV and $Γ=(112 \pm 1 \pm 8)$~MeV, and for the excited state $a_2^\prime$ we obtain $M=(1720 \pm 10 \pm 60)$~MeV and $Γ=(280\pm 10 \pm 70)$~MeV, respectively.

hep-ph↗
arXiv2013

Analytic structure of $ϕ^4$ theory using light-by-light sum rules

We apply a sum rule for the forward light-by-light scattering process within the context of the $ϕ^4$ quantum field theory. As a consequence of the sum rule a stringent causality criterion is presented and the resulting constraints are studied within a particular resummation of graphs. Such resummation is demonstrated to be consistent with the sum rule to all orders of perturbation theory. We furthermore show the appearance of particular non-perturbative solutions within such approximation to be a necessary requirement of the sum rule. For a range of values of the coupling constant, these solutions manifest themselves as a physical bound state and a $K$-matrix pole. For another domain however, they appear as tachyon solutions, showing the inconsistency of the approximation in this region.

hep-ph↗
arXiv2009

Inclusive distributions in the unitarized pomeron models

High energy inclusive hadron production in the central kinematical region is analyzed within the models of unitarized pomeron. It is shown that the sum of multipomeron exchanges with intercept $α_P(0)>1$ reproduce qualitatively contribution of the triple pole (at $t=0$) pomeron to inclusive cross section. Basing on this analogy we then suggest a general form of unitarized pomeron contributions (in particular the dipole or tripole pomeron) to inclusive cross section. They lead to a parabolic form of the rapidity distribution giving $ \propto \ln^3s$ (tripole) or $ \propto \ln^2s$ (dipole). The models considered with suggested parametrization of $p_t$-dependence for cross sections well describe the rapidity distributions data in $pp$ and $\bar pp$ interactions at energy $\sqrt{s}\geq 200$ GeV. The predictions for one particle inclusive production at LHC energies are given.

hep-ph↗