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The scalar and vector meson exchange contributions to the doubly radiative decays $\eta^{(\prime)}\to\pi^0\gamma\gamma$ and $\eta^\prime\to\eta\gamma\gamma$ are analysed within the Linear Sigma Model and Vector Meson Dominance frameworks,…

High Energy Physics - Phenomenology · Physics 2020-09-02 Rafel Escribano , Sergi Gonzàlez-Solís , Renata Jora , Emilio Royo

We have studied the correlations among the three absolute neutrino mass observables - the effective Majorana mass ($m_{ee}$) which can be obtained from neutrinoless double beta decay, the electron neutrino mass ($m_{\beta}$) which is…

High Energy Physics - Phenomenology · Physics 2021-03-31 Srubabati Goswami , Vishnudath K N

We examine the subprocess $\gamma\gamma \to t\bar{c}+\bar{t}c$ at electron-positron colliders in the two-Higgs-doublet model with flavor-changing scalar couplings, where all the one-loop contribuions are considered, and the results are…

High Energy Physics - Phenomenology · Physics 2011-07-19 Jiang Yi , Zhou Mian-Lai , Ma Wen-Gan , Han Liang , Zhou Hong , Han Meng

We investigate the magnetic dipole decays $V\to P\gamma$ of various heavy-flavored mesons such as $(D,D^*,D_s,D^{*}_s,\eta_c, J/\psi)$ and $(B,B^*,B_s,B^*_s,\eta_b,\Upsilon)$ using the light-front quark model constrained by the variational…

High Energy Physics - Phenomenology · Physics 2008-11-26 Ho-Meoyng Choi

The NA60 experiment at the CERN SPS has studied low-mass muon pairs in 158A GeV In-In collisions. The mass and pT spectra associated with peripheral collisions can quantitatively be described by the known neutral meson decays. The high data…

High Energy Physics - Phenomenology · Physics 2009-06-22 NA60 Collaboration , R. Arnaldi

Properties of a scalar $\sigma$-meson are investigated in the two-flavor Nambu-Jona-Lasinio model with the Polyakov loop. Model analysis of the phase diagram of strong interacting matter is performed. The temperature dependence of the…

Nuclear Theory · Physics 2015-05-27 A. V. Friesen , Yu. L. Kalinovsky , V. D. Toneev

We investigate the decays of pi^0, eta and eta-prime into two photons in an effective U(3) chiral Lagrangian approach without employing large N_c arguments. Tree level and one-loop contributions from the anomalous Wess-Zumino-Witten…

High Energy Physics - Phenomenology · Physics 2014-11-17 B. Borasoy , R. Nissler

The rates and spectra of the anomalous $\eta\to\pi^+\pi^-\gamma$ and $\eta' \to\pi^+\pi^-\gamma$ decays are calculated. The approach is based on the effective meson Lagrangian obtained in the Nambu-Jona-Lasinio model with vector and…

High Energy Physics - Phenomenology · Physics 2021-08-24 A. A. Osipov , A. A. Pivovarov , M. K. Volkov , M. M. Khalifa

We study the anomalous decays $\pi^0, \eta \to\gamma\gamma$ in the framework of the three--flavor Nambu--Jona-Lasinio [NJL] model, in the vacuum and in quark matter in $\beta$ --equilibrium. It is found that the behavior of the relevant…

High Energy Physics - Phenomenology · Physics 2007-05-23 Pedro Costa , M. C. Ruivo , Yu. L. Kalinovsky

Eta-eta' mixing is discussed in the quark-flavor basis with the hypothesis that the decay constants follow the pattern of particle state mixing. On exploiting the divergences of the axial vector currents - which embody the axial vector…

High Energy Physics - Phenomenology · Physics 2009-11-07 Th. Feldmann , P. Kroll

We study strong and radiative decays of excited singly heavy baryons (SHBs) using an effective chiral Lagrangian based on the diquark picture proposed in Ref. [1]. The effective Lagrangian contains a $U_A (1)$ anomaly term, which induces an…

High Energy Physics - Phenomenology · Physics 2020-12-30 Yohei Kawakami , Masayasu Harada , Makoto Oka , Kei Suzuki

The \tau -> (\omega, \phi)P^-\nu decays, where P^-=\pi^-, K^-, are considered within a phenomenological model with dominance of meson intermediate states. We assume SU(3) flavor symmetry to fix some of the unknown strong interaction…

High Energy Physics - Phenomenology · Physics 2008-11-26 A. Flores-Tlalpa , G. Lopez Castro

Lepton flavor violating decays $\ell_{\alpha} \to \ell_{\beta} \gamma$, being forbidden in the Standard Model framework, provide a sensitive probe for new physics. We study these processes in a seesaw variant in which small neutrino masses…

High Energy Physics - Phenomenology · Physics 2025-10-29 Enrique Ramírez , Héctor Novales-Sánchez , Humberto Vázquez-Castro , Mónica Salinas

We consider the flavor-changing decays of the Higgs boson in a grand unified theory framework which is based on the SU(5) gauge group and implements the principle of minimal flavor violation. This allows us to explore the possibility of…

High Energy Physics - Phenomenology · Physics 2016-12-07 Seungwon Baek , Jusak Tandean

The known ratio of the branching fractions for D_s^* --> D_s pi^0 and D_s^* --> D_s gamma may be used to extract the coupling of eta mesons to strange quarks once the value of the pi^0-eta mixing angle is known. This requires that realistic…

High Energy Physics - Phenomenology · Physics 2009-11-07 T. A. Lahde , D. O. Riska

In this work, we analyze the Higgs boson decay channels, specifically, $h{\rightarrow}\gamma\gamma$, $h{\rightarrow} VV^*$ (with $V=Z,W$), and $h{\rightarrow} f\bar{f}$ (for $f=b,c,\tau$) within the flavor-dependent $U(1)_F$ model (FDM). We…

High Energy Physics - Phenomenology · Physics 2025-12-30 Zhan Cao , Jin-Lei Yang , Ti-Bin Hou , Tai-Fu Feng

We present an effective Lagrangian formalism for the calculation of flavour changing neutral and charged scalar currents in weak decays including $SU(2)\times U(1)$ symmetry breaking effects and the effects of the electroweak couplings…

High Energy Physics - Phenomenology · Physics 2014-11-17 A. J. Buras , P. H. Chankowski , J. Rosiek , L. Slawianowska

By considering the background field method we calculate one-loop polarization corrections to the coupling constant of the flavor-U(5) Nambu-Jona-Lasinio (NJL) model with degenerate up and down quarks. They break flavor and chiral…

High Energy Physics - Phenomenology · Physics 2024-08-16 Willian F. de Sousa , Fabio L. Braghin

Two-photon decays of rho and omega mesons and strong decays rho -> eta pi and omega -> pi pi are described in the quark Nambu-Jona-Lasinio(NJL) model in dense medium. Decays of rho-meson are especially interesting because they contain…

High Energy Physics - Phenomenology · Physics 2016-09-06 A. E. Radzhabov , M. K. Volkov

The phenomenological 3P0 decay model has been extensively applied to calculate meson strong decays. The strength \gamma\ of the decay interaction is regarded as a free flavor independent constant and is fitted to the data. We calculate…

High Energy Physics - Phenomenology · Physics 2015-06-05 J. Segovia , D. R. Entem , F. Fernandez