相关论文: Charmonium in the instantaneous approximation

In this paper, we study the problem of transient signal analysis. A signal-dependent algorithm is proposed which sequentially identifies the countable sets of decay rates and expansion coefficients present in a given signal. We…

Galileo, in the XVII century, observed that the small oscillations of a pendulum seem to have constant period. In fact, the Taylor expansion of the period map of the pendulum is constant up to second order in the initial angular velocity…

We calculate the rate of the decay $\mu \to e\gamma$ and the electric dipole moment of the electron in the left-right supersymmetric model when the breaking of parity occurs at a considerably large scale. The low-energy flavor violation in…

The charmonium mass spectrum is considered in the framework of the constituent quark model with the relativistic treatment of the c quark. The obtained masses are in good agreement with the existing experimental data including the mass of…

We study the time evolution of the entangled kaon system by considering the Liouville - von Neumann equation with an additional term which allows for decoherence. We choose as generators of decoherence the projectors to the 2-particle…

We make progress on a question by Vemuri on the optimal Gaussian decay of harmonic oscillators, proving the original conjecture up to an arithmetic progression of times. The techniques used are a suitable translation of the problem at hand…

Our understanding of high-lying states within the charmonium family remains incomplete, particularly in light of recent observations of charmonium states at energies around 4 GeV. In this study, we investigate the spectroscopic properties…

This work generalizes the classical metriplectic formalism to model Hamiltonian systems with nonconservative dissipation. Classical metriplectic representations allow for the description of energy conservation and production of entropy via…

In this work, we calculate the charmonium spectrum and strong decay widths of cc states. The calculations are performed using the quark potential model with which incorporates the relativistic effects. The resulting cc spectrum exhibits a…

The BESIII Collaboration has recently reported two measurements of the two-photon decay width of the $\eta_c$ meson. The 2024 result is significantly larger than most theoretical and empirical expectations, while a subsequent measurement…

The heavy quarkonia (Charmonium \(c\bar{c}\) and Bottomonium \(b\bar{b}\)) are investigated in the framework of the instantaneous BS-equation (Salpeter equation). We parametrize confinement alternatively by a linearly rising scalar or a…

Transient stability is crucial to the reliable operation of power systems. Existing theories rely on the simplified electromechanical models, substituting the detailed electromagnetic dynamics of inductor and capacitor with their impedance…

This paper is devoted to studying Hamiltonian oscillators in 1:1:1:1 resonance with symmetries, which include several models of perturbed Keplerian systems. Normal forms are computed in Poisson and symplectic formalisms, by mean of…

The masses of charmonium s and p-states, pseudoscalar and vector decay constants, leptonic, hadronic as well as radiative decay widths for charmonia have been computed in the framework of extended harmonic confinement model without any…

Recent results on charmonia decays at BES/BEPC are reported, including the observation of psi'-->K_S K_L, psi'--> Vector + Tensor for the measurement of the relative phase between the strong and electromagnetic decays of psi' and a test of…

Radiative charmonium decays from the BESII sample of 14$\times10^{6}$ $\psi(2S)$-events into two different final states, $\gamma K^+K^-$ and $\gamma\pi^+\pi^-$, are analyzed. Product branching fractions for $\psi(2S)\to\gamma X\to…

In this paper, a new approach for constructing Lagrangians for driven and undriven linearly damped systems is proposed, by introducing a redefined time coordinate and an associated coordinate transformation to ensure that the resulting…

The small angle approximation often fails to explain experimental data, does not even predict if a plane pendulum's period increases or decreases with increasing amplitude. We make a perturbation ansatz for the Conserved Energy Surfaces of…

The vector and pseudoscalar decay constants are calculated in the framework of the Field Correlator Method. Di-electron widths: $\Gamma_{ee}(J/\psi)=5.41$ keV, $\Gamma_{ee}(\psi'(3686))=2.47$ keV, $\Gamma_{ee}(\psi''(3770))=0.248$ keV, in…

The nonequilibrium tunnelling center model of a localized electronic level coupled to a fluctuating two-state system and to two electronic reservoirs, is solved via an Anderson-Yuval-Hamann mapping onto a plasma of alternating positive and…