arXiv subjects

K. Nurlan

Publications and source records attributed to K. Nurlan.

31 records · Page 2Linked to original sources

arXiv2022

Low-energy interactions of mesons with participation of the first radially excited states in $U(3) \times U(3)$ NJL model

The $U(3) \times U(3)$ chiral symmetric NJL model describing pseudoscalar, vector, and axial vector mesons in both the ground state and first radially excited states is shortly presented in this review. In this model, it is possible to describe a large number of low-energy interactions of mesons, $τ$ lepton decays into mesons and processes of meson production in electron-positron annihilations in satisfactory agreement with the experiments. In describing a number of processes, it turned out to be necessary to take into account the interactions of mesons in the final state.

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arXiv2021

$1/N_c$ approximation and universality of vector mesons

In this work, we argue that the observed differences in the value of the vector coupling constant extracted from the decays $ρ\to ππ$ ($g_ρ = 6.0$), $ρ\to l^+l^-$ ($g_ρ = 5.0 $) and $ω\to l^+ l^-$ ($g_ρ = 5.7$), where $l=e,μ$, are an indication of the important role played by the $1/N_c$ corrections in the description of these processes. We show that an emission of a photon by charged meson loops in the $ρ^0, ω,ϕ\toγ$ transitions is a key process that allows to describe above vector meson decays into two leptons with a single value $g_ρ= 6.0$. Our result supports the idea of universality of neutral vector mesons and clarifies the role of accounting of $1/N_c$ corrections to its fulfilment.

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arXiv2021

The second-class current decays $τ\to πη(η') ν_τ$ in the NJL model including the interaction of mesons in the final state

The effect of the interaction of mesons in the final state is additionally considered within the description of $τ\to πη(η') ν_τ$ decays. This interaction is taken into account at the level of production of intermediate pions. One of them, in turn, might be transited into $η$ or $η'$ mesons. Our results do not exceed the experimentally established branching fractions, and they are in agreement with the results of other theoretical studies.

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arXiv2020

Fixing the vector coupling constant $g_ρ= 5.0$ in the NJL model and final-state interactions in processes $ρ\to e^+e^-[μ^+μ^-]$, $ρ\to π^+π^-$, $τ\to π^-π^0ν_τ$, and $e^+e^-\toπ^+π^-$

The possibility to use the width of the decay $ρ\to e^{+}e^{-}$ to fix the input parameter $g_ρ=5.0$ of the $SU(2) \times SU(2)$ chiral-symmetric Nambu--Jona-Lasinio model is discussed. It is shown that for a consistent simultaneous description of the processes $ρ\to e^{+}e^{-}$, $ρ\to π^{+}π^{-}$, $τ^{-} \to π^{-}π^{0} ν_τ$, and $e^{+}e^{-} \to π^{+}π^{-}$ can be constructed. Taking into account the interaction of pions in the final state appears to be important. The obtained theoretical results for the considered processes are in a satisfactory agreement with experimental data.

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arXiv2020

On the mixing angle of the vector mesons $ω(782)$ and $ϕ(1020)$

In the present work, the mixing angle of the vector $ω(782)$ and $ϕ(1020)$ mesons is estimated in the framework of Nambu--Jona-Lasinio model. The decay $ϕ\to π^{0} γ$ is considered as a basic process to determine this angle. The obtained value is compared with the results of the other authors. Besides, the width of the decay $ϕ\to 3π$ and the cross-section of the process $e^{+}e^{-} \to π^{0} ϕ$ are calculated by using this angle.

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arXiv2019

The decay $τ\to K^{*0}(892) K^- ν_τ$ in the extended NJL model

In the extended Nambu -- Jona-Lasinio model, the decay width of $τ\to K^{*0}(892) K^- ν_τ$ is calculated. The contributions from the contact diagram and diagrams with intermediate axial-vector, vector and pseudoscalar mesons in the ground and first radially excited states are taken into account. It is shown that axial-vector and vector channel with a contact diagram give a dominant contribution to the decay width. The obtained results for the decay width $τ\to K^{*0}(892) K^- ν_τ$ are in satisfactory agreement with experimental data. A prediction for differential distribution over the invariant mass of the meson pair $K^{*0}(892) K^-$ is given.

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arXiv2019

The decay $τ\to K^{*-}(892) ην_τ$ in the NJL model

The decay width $τ\to K^{*-}(892) ην_τ$ was calculated in the Nambu--Jona-Lasinio model. Four channels were taken into account: the contact channel (the final states are directly producted from lepton current without any intermediate meson states), the axial-vector channel with two intermediate physical states $K_{1}(1270)$ and $K_{1}(1400)$, the vector channel with intermediate $K^{*}(892)$ meson and the pseudoscalar channel with intermediate $K$ meson. It is shown that the first two channels give the dominant contribution to the decay width. Of the remaining two channels, the pseudoscalar channel plays a more prominent role. The final result is in satisfactory agreement with experimental data. Prediction for the differential decay width is presented.

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arXiv2019

The decays $τ\to [ω(782), ϕ(1020)] K^{-} ν_τ$ in the extended NJL model

In the extended Nambu--Jona-Lasinio model, the decay widths of the processes $τ\to [ω(782), ϕ(1020)] K^{-} ν_τ$ were calculated. The intermediate channels with axial vector ($K_{1}(1270)$, $K_{1}(1400)$ and $K_{1}(1650)$), vector ($K^{*}(892)$ and $K^{*}(1410)$) and pseudoscalar ($K$ and $K(1460)$) mesons were considered. The results for these processes are in satisfactory agreement with the experimental data.

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arXiv2019

The tetraquark $K_{1}(1400)$ in the decays $τ\to [ω(782), ϕ(1020)] K^{-} ν_τ$

In the extended Nambu--Jona-Lasinio model, the decay widths of the processes $τ\to [ω(782), ϕ(1020)] K^{-} ν_τ$ were calculated. The intermediate strange quark-antiquark mesons in both the ground and the first radially excited states were taken into account. The meson $K_{1}(1400)$, being a possible candidate for the role of the tetraquark meson, was also taken into account as an intermediate state. The result for the process $τ\to ω(782) K^{-} ν_τ$ is in satisfactory agreement with the experimental data. Simultaneously, the result for the decay $τ\to ϕ(1020) K^{-} ν_τ$ is in agreement with the experimental data with precision $1.3 σ$.

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arXiv2019

The decays $τ\rightarrow (K, K(1460))ν_τ$ and the value of the weak decay coefficients ${F}_{K}$ and ${{F}_{{K}^{'}}}$ in the extended NJL model

In the extended NJL model, the decay widths of $τ\rightarrow (K, K(1460))ν_τ$, $(K, K(1460))\rightarrow μν_μ$ are calculated. The contributions from intermediate axial-vector mesons ${K}_{1}(1270)$, ${K}_{1}(1400)$ and the first radially excited state ${K}_{1}(1650)$ are taken into account. Estimates for the weak decay coefficients ${F}_{K}$ and ${{F}_{{K}^{'}}}$ are given. Predictions are made for the width of $τ\rightarrow K(1460)ν_τ$ decay and ${{F}_{{K}^{'}}}$ constant.

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arXiv2018

Low energy process $e^{+}e^{-} \rightarrow K^{+} K^{-}$ in the extended Nambu-Jona-Lasinio model

In the extended Nambu-Jona-Lasinio model, the process of production of charged kaon pair on colliding electron-positron beams in the energy interval 1 - 1.7 GeV is described. In studying of this process, we take into account the contact terms when the pairs $K^{+}$ $K^{-}$ are generated by an intermediate photon, and processes with intermediate vector mesons $ρ$, $ω$ and $ϕ$ in the ground and in the first radially excited states. The results obtained here are compared with experimental data recently received in Novosibirsk and in Stanford.

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arXiv2017

Production of $ρ(770)$, $η$ pairs in the decays $ρ(1450)\rightarrow ρ(770)η$, $τ\rightarrow ρ(770)ην_τ$, and in the process of $e^{+}e^{-} \rightarrow ρ(770)η$ in the Extended Nambu - Jona-Lasinio model

Production of $ρ(770)$, $η$ pairs at colliding of electron-positron beams and in the decays $ρ(1450)\rightarrow ρ(770)η$, $τ\rightarrow ρ(770)ην_τ$ is calculated in the framework of the Nambu - Jona-Lasinio model. In the process of electron-positron annihilation and the $τ$ - lepton decay the contributions of the intermediate $ρ(770)$ vector meson in the ground and first radially excited state are taken into account. The theoretical prediction for the decay $τ\rightarrow ρ(770)ην_τ$ is given. The obtained results for other processes are in satisfactory agreement with the experimental data.

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arXiv2016

The decays $τ\to ν_τ (K^{}(892), K^{}(1410), K_1(1270), K_1(1650), a_1(1260), a_1(1640))$ in the Extended Nambu-Jona-Lasinio Model

The decays $τ\to ν_τ (K^{*}(892), K^{*}(1410), K_1(1270), K_1(1650), a_1(1260), a_1(1640))$ in the extended NJL model are calculated. The results obtained for the decays are $τ\to ν_τ (K^{*}(892), K^{*}(1410), K_1(1270))$ in a satisfactory agreement with the experimental data. There are no experimental data for other types of decay. Therefore, the obtained results should be considered as predictions for further experiments.

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