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K. Nurlan

Publications and source records attributed to K. Nurlan.

At least 19 recordsLinked to original sources
arXiv2026

Decay widths of radially excited vector mesons of the $U(3)$ nonet with production of three pseudoscalar mesons in the extended NJL model

In the extended NJL model, the decays of the first radially excited vector mesons $\rho'$,$\omega'$, $\phi'$ and ${K^*}'$ with production of $3P$, where $P=K,\pi,\eta$ are calculated. The box channels and the channels with intermediate vector mesons in the ground and first radially excited states are considered. The obtained results can be considered as predictions for future experiments.

hep-ph↗
arXiv2026

Description of the process $e^+ e^- \to \pi^0\pi^0 \gamma$ in the extended NJL model

The cross section of the process $e^+ e^- \to \pi^0\pi^0 \gamma$ is calculated in the extended NJL quark model. The vector channel with the intermediate $\rho$, $\omega$, $\rho'$ and $\omega'$ mesons is considered. The main contribution is given by the intermediate radially excited $\rho'$ meson. The role of the channel with the intermediate scalar meson is also discussed.

hep-ph↗
arXiv2026

Two-body decays of radially excited $\eta(1295)$ and $\eta(1475)$ mesons in the extended NJL model

In the extended NJL model, two-body strong decays of the radially excited $\eta(1295)$ and $\eta(1475)$ mesons are described. It is shown that the two-body decays $\eta(1475)\to K_0^*K, a_0\pi$ play a dominant role in determining the width of the radially excited meson $\eta(1475)$. At the same time, the decays $\eta(1475)\to K^*K$ make a significantly smaller contribution to the total width. It is shown that two-particle decays give only a negligible contribution to the total width of the $\eta(1295)$.

hep-ph↗
arXiv2026

Chiral anomaly in the $\eta^{(\prime)}\to\pi^+\pi^-\gamma$ and $\eta^{(\prime)}\to\pi^+\pi^-l^+l^-$ decays

We report the presence of a flavor-violating correction to the $VAAA$-type anomaly, $\delta^{(\prime)}$, induced by the surface terms of the anomalous quark triangle diagram, previously found in the $\eta,\eta'\to\pi^+\pi^-\gamma$ decay amplitudes, and investigate its impact on the corresponding semileptonic decay modes of $\eta$ and $\eta'$. The magnitude of $\delta^{(\prime)}$ can be set from the experimental data on the $\eta^{(\prime)}\to \pi^+\pi^-\gamma$ decay width. We then estimate another low-energy constant, the slope parameter $\alpha^{(\prime)}$. The impact of different schemes for describing $\eta$-$\eta^\prime$ mixing on the value of $\delta^{(\prime)}$ and $\alpha^{(\prime)}$ is discussed. The predictions are shown to be in complete agreement with the available experimental data.

hep-ph↗
arXiv2025

Decays $f_1 \to a_0 \pi,\pi \pi \pi(\eta)$ and $f_1 \to K K \pi$ in the chiral $U(3) \times U(3)$ quark NJL model

The branching fractions of the axial vector meson decays $f_1 \to a_0 \pi,\pi\pi\eta$, $f_1 \to \rho \pi,\pi\pi\pi$ and $f_1 \to KK\pi$ are calculated in the standard $U(3) \times U(3)$ quark NJL model. The intermediate channels with the states $a_0(980)\pi$ and $f_0(500)\eta$ are taken into account in the decay $f_1 \to \pi\pi\eta$. In the case of the scalar mesons, the $\bar{q}q$ representation as a chiral symmetric partners of the pseudoscalar mesons is used. It is shown that the decays $f_1 \to \rho \pi$ and $f_1 \to3\pi$ occur due to the mass difference of the $u$ and $d$ quarks. All the results are obtained without using any additional arbitrary parameters and are in satisfactory agreement with the known experimental data.

hep-ph↗
arXiv2025

Decays $\tau \to \pi \pi \eta\nu_\tau$ and $\tau \to \pi\eta\eta\nu_\tau$ in the extended Nambu-Jona-Lasinio model

In the framework of the extended Nambu-Jona-Lasinio model, the processes $\tau \to \pi \pi \eta(\eta')\nu_\tau$ and $\tau \to \pi\eta\eta(\eta')\nu_\tau$ are considered taking into account mesons in the ground and first radially excited intermediate states. It is shown that in the processes $\tau \to \pi \pi \eta(\eta')\nu_\tau$ the vector channel is dominant, and in the processes $\tau \to \pi\eta\eta(\eta')\nu_\tau$ the main contribution is given by the axial vector channel. The scalar meson $a_0$ plays a dominant role in processes with two $\eta$-mesons in the final state. The significance of the relative phase between the ground and first radially excited states for these processes is shown. The obtained results for the $\tau \to \pi \pi \eta\nu_\tau$ process are in satisfactory agreement with the recent experimental data from BaBar and CMD-3, which differ from the averaged values given in the PDG tables.

hep-ph↗
arXiv2024

Decays $\tau \to f_0(\pi,K) \nu_\tau$ and $\tau \to 3 \pi \nu_\tau$ accounting for the contribution of $f_0(500)$

In the $U(3) \times U(3)$ quark NJL model, $\tau$ lepton decays with the production of scalar mesons $f_0(\pi,K])$ and neutrinos are studied, where $f_0=f_0(500), f_0(980)$. It is shown that these decays mainly occur via contact channels and channels with axial-vector mesons $a_1$, $K_1(1270)$ and $K_1(1400)$. All mesons are considered as quark-antiquark states in this case. The obtained results can be considered as predictions for future experiments. The obtained estimates for the branching fractions of the $\tau \to \pi^-2\pi^0 \nu_\tau$ decay taking into account the contributions of the $\rho\pi$ and $f_0(500)\pi$ states are in satisfactory agreement with experimental data.

hep-ph↗
arXiv2024

Weak semileptonic decays of vector mesons in the NJL model

The decay widths of $V \to K(\pi) l \bar{\nu}_l $ are calculated within the Nambu--Jona-Lasinio model, where $V=K^*, \rho, \omega, \phi$ and $l=\mu, e$. The results are obtained using the previously fixed model parameters without introducing any arbitrary parameters. The obtained results are considered as predictions due to the absence of experimental data.

hep-ph↗
arXiv2024

Description of the processes $e^+ e^- \to \pi^+ \pi^-$ and $\tau^- \to \pi^- \pi^0 \nu_\tau$ in the NJL model with value of the vector coupling constant $ g_{\rho} = 6$

It is shown that the processes $e^+ e^- \to \pi^+ \pi^-$ and $\tau^- \to \pi^- \pi^0 \nu_\tau$ can be described in a unified approach in satisfactory agreement with experiment using the vector coupling constant $g_{\rho} = 6$. In this case, in addition to quark loops, it is also necessary to take into account meson loops corresponding to the next order in $1/N_c$. These loops must be taken into account when describing the $\gamma (W) \to \rho$ transition, as well as in interaction of mesons in the final state.

hep-ph↗
arXiv2024

Description of the processes $e^+e^- \to K^+K^-\pi^0$ and $e^+e^- \to K^+K^-\eta$ within the extended NJL model

In the framework of the $U(3) \times U(3)$ extended Nambu-Jona-Lasinio model, the processes $e^+e^- \to K^+K^-\pi^0$ and $e^+e^- \to K^+K^-\eta$ are described taking into account both ground and first radially excited intermediate meson states. It is shown that channels with radially excited $\phi(1680)$ meson are dominant in both processes. The influence on the results of the appearance of phase factors of radially excited intermediate states, the existence of which is indicated by experimental data, is discussed.

hep-ph↗
arXiv2023

Decays of radially excited vector mesons $ρ'$ and $ω'$ in the extended NJL model

The decay widths of $ρ' \to ππ, ωπ, ρη$, $ω' \to ρπ, ωη$ and $π' \to ρπ$ are recalculated within the extended NJL quark model. It is shown that the mass of $ρ'(1450)$ meson in the derived in the NJL model agrees with the one given in Particle Data Group tables but significantly deviates from the recent result of CMD-3 collaboration. Comparisons with earlier theoretical results are presented.

hep-ph↗
arXiv2023

The decays $τ\to [K^- K^0 π^0, K^- K^+ π^-, K^0 \bar{K^0} π^-] ν_τ$ in the NJL quark model

The $τ$ lepton decays $τ\to [K^- K^0 π^0, K^- K^+ π^-, K ^0 \bar{K^0} π^-] ν_τ$ are described in the $U(3) \times U(3)$ NJL quark model. The contact channel and intermediate channels with axial-vector, vector and pseudoscalar mesons are taken into account. It is shown that the strange scalar meson $K^*_0$ plays an important role in these processes in addition to the intermediate vector meson $K^*$. The obtained results are in satisfactory agreement with the recent experimental data within the experimental and theoretical uncertainties.

hep-ph↗
arXiv2023

Three-meson $τ$ decays involving kaons and $η$ mesons in the NJL model

Branching fractions of decays $τ\to K^0 π^- ην_τ$, $τ\to K^- π^0 ην_τ$, $τ\to K^-K^0 ην_τ$ and $τ\to K^- ηην_τ$ are calculated in the $U(3)\times U(3)$ chiral NJL quark model. The contact, vector, axial-vector and pseudoscalar channels are considered. It is shown that the axial vector channel is dominant. The obtained results are in satisfactory agreement with experiment.

hep-ph↗
arXiv2023

Decays $τ\to 3K ν_τ$ in $U(3)\times U(3)$ quark NJL model

The widths of the decays $τ\to K^- K^+ K^- ν_τ$ and $τ\to K^- K^0 \bar{K}^0 ν_τ$ are calculated in the $U(3)\times U(3)$ chiral quark NJL model. Four channels are considered: contact, axial vector, vector and pseudoscalar channels. It is shown that the dominant contribution is given by the axial vector channel with an intermediate $ϕ$ meson. The obtained results are in satisfactory agreement with the experimental data.

hep-ph↗
arXiv2022

$τ$ lepton decays with production of strange scalar mesons $K^*_0(700)$ and $K^*_0(1430)$ in the extended NJL model

The branching fractions of $τ$ lepton decays with the production of strange scalar mesons both in the ground and first radially excited states $τ\to ν_τ[K^*_0(700), K^*_0(1430)]$ and $τ\to ν_τ[K^*_0(700)π, K^*_0(1430)π, K^*_0(700) K, K^*_0 (700)η]$ are calculated in the extended $U(3) \times U(3)$ chiral quark NJL model. All mesons are considered as $q\bar{q}$ systems. The obtained results should be considered as predictions for future experiments.

hep-ph↗
arXiv2022

The decay $η' \to πρ$ in the chiral NJL model

The branching fraction of the decay $η' \to πρ$ is calculated in the chiral quark NJL model. The decay exists due to the mass difference between $u$- and $d$-quarks leading to $π^{0}-η^{'}$ mixing. Two different approaches are applied: the approximate calculation of this process taking into account the transition $π^{0}-η^{'}$ explicitly without dioganalisation and a more precise approach consisting in the diagonalisation of the singlet and octet states leading to the physical fields $π^{0}$, $η$ and $η^{'}$. The obtained results are in satisfactory agreement with current experimental data.

hep-ph↗
arXiv2022

Semileptonic decays of $ρ$, $ω$, $ϕ$, $η$ and $η'$ mesons in ground and first radially excited states in the $U(3)\times U(3)$ NJL model

In the extended $U(3)\times U(3)$ NJL model, semileptonic decays of $ρ$, $ω$, $ϕ$, $η$ and $η'$ mesons in both the ground and first radially excited states are described. Quark loops of the anomalous type are considered, which are based on the vertex $η\to VV$. The obtained results are in satisfactory agreement with the existing experimental data. In addition, a number of predictions for experimentally unmeasured decays of radially excited mesons are presented.

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