Ordinary Resonance Research Articles

The flavor of a minimal composite S1 leptoquark and the b→cτν¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ b\ o c\ au \\overline{\ u} $$\\end{document} anomaly

Several experiments have measured a deviation in B → D(∗) semileptonic decays, that point to new physics at the TeV scale violating lepton flavor universality. A scalar leptoquark S1, with a suitable structure of couplings in flavor space, is known to be able to solve this anomaly modifying b→cτν¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ b\ o c\ au \\overline{\ u} $$\\end{document}. In the context of composite Higgs models, we consider a theory containing H and S1 as Nambu-Goldstone bosons (NGBs) of a new strongly interacting sector, with ordinary resonances at a scale O10\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{O}(10) $$\\end{document} TeV. Assuming anarchic partial compositeness of the Standard Model (SM) fermions we calculate the potential of the NGBs that is dominated by the fermions of the third generation, we compute RD∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {R}_{D^{\\left(\\ast \\right)}} $$\\end{document} and estimate the corrections to flavor observables by the presence of S1. We find that the SM spectrum and mS1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {m}_{S_1} $$\\end{document} ∼ TeV can be obtained with a NGB decay constant of order ∼ 5 TeV. We obtain a robust correlation between the main corrections to RD∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {R}_{D^{\\left(\\ast \\right)}} $$\\end{document}, BK∗νν\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {B}_{K^{\\left(\\ast \\right)}\ u \ u} $$\\end{document} and gτ/gμ, that leads to a sever bound on RD∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {R}_{D^{\\left(\\ast \\right)}} $$\\end{document}, roughly 2σ below the experimental value. Besides the bounds on the flavor observables gτW\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {g}_{\ au}^W $$\\end{document}, BR(τ → μγ) and ∆mBs\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\Delta {m}_{B_s} $$\\end{document} are saturated, with the first one requiring a coupling between resonances g* ≲ 2, whereas the second one demands mS1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {m}_{S_1} $$\\end{document} ≳ 1.7 TeV, up to corrections of O1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{O}(1) $$\\end{document}.

Dynamics analysis and parameter optimization of a vibration absorber with geometrically nonlinear inerters

The inerter-based dynamic vibration absorber (DVA) is a promising technique for vibration control. In most studies, the inerter is usually mounted in the same direction as that of the motion, which may not adequately reflect the vibration suppression capability and the two-terminal inertial feature of the inerter, and even weakens the performance of vibration absorbers. Considering the potentiality of improving the control performance by unconventional mounting methods, a rarely studied structure of geometrically nonlinear inerters is introduced into the vibration absorber system. This novel vibration absorber is presented to investigate the following issues, that is, the unknown coupled dynamical behavior between the complex nonlinear force with inertia, damping, and stiffness terms generated by this structure and the vibration absorber system, the possibility of vibration absorption facilitated by this structure, and the full utilization of the two-terminal inertial feature of the inerter. The approximate solutions of the system are obtained using the harmonic balance method. The influence of each variable on the system response is analyzed, and the system parameters are optimized by using the grey wolf algorithm. In addition to the ordinary resonance phenomenon, there are also dynamic features such as soft characteristic jump behavior and response loops at certain parameter range. As a nonlinear system, this model is more stable than the nonlinear energy sink (NES). The optimized amplitude-frequency curves are equal-peak stable, similar to the linear vibration absorbers. The robustness of system parameters is high for small inerter-mass ratios or excitation amplitudes, which is better than DVAs. Compared to the classical linear vibration absorber, NES, and improved NES, the vibration suppression capacity and damping bandwidth of this model are enhanced. In comparison, it is also found that this model has smaller optimum parameters than the classical NES and equivalent inerter-enhanced DVA and NES. This model offers a new solution for the design and implementation of passive vibration absorbers with comprehensive performance.

A double negative (DNG) metamaterial based on parallel double-E square split resonators for multi-band applications: Simulation and experiment

In this paper, we designed and investigated a parallel double-E shaped structure based on double negative (DNG) metamaterial (MTM) both numerically and experimentally, which can be utilized for multiband applications. We used the Computer Simulation Technology (CST) Microwave Studio electromagnetic simulator to design the MTM and obtain the numerical results. The proposed MTM has a unit cell dimension of 8 × 8 × 1.57 mm3, and Rogers RT 5880 was used as the substrate, resulting in a high effective medium ratio (EMR) value of 15.61. The DNG metamaterial can cover multiband frequencies (S and C bands) and produce three resonance frequencies of 2.40, 4.50, and 7.24 GHz. Parametric studies were performed for different configurations by changing the type of substrates, substrate thicknesses, split gaps, and unit cell arrays to optimize the proposed design. An equivalent circuit was validated using the advanced design system (ADS) software and compared to the CST simulated results, which showed good agreement. The proposed structure is highly significant due to its low profile (small size) and ordinary resonator arrangement, which produced double negative properties with a high EMR over a wide range of frequencies. The recommended structure can be useful for different applications such as wireless communications, weather radar, satellite communication, and wireless sensor networks.

CW-EPR spectra of P1 centers in HPHT diamond in the vicinity of Rabi resonance: possible standard for [formula omitted] evaluation in EPR and DNP enhanced NMR spectroscopies

Synthetic commercial type-IIa diamond crystal containing low concentration of P1 (Ns0) centers ([Ns0] <1ppm) was examined as a possible calibration standard for evaluating microwave magnetic field intensity (B1) in the spectrometer cavity. The reliability of this standard was experimentally and theoretically tested by employing two different types of microwave cavities with different distributions of B1 values. The procedure relies on the ordinary continuous wave electron paramagnetic resonance (CW-EPR) with magnetic field modulation (ωrf/2π=100 kHz) applied under the regime of the microwave power (PMW) saturation of the out-of-phase first harmonic signal. The power saturation procedure for PMW∼B11/2 was analyzed with respect to the change of spectral lineshape when Rabi frequency (ω1=γB1, γis the electron gyromagnetic ratio) approaches to ωrf. The phenomenon of the inversion of sideband lines while passing the Rabi resonance condition (ω1=ωrf) was analyzed. In specific, from the simulation of the experimental lineshapes in the close vicinity of Rabi resonance (ω1≈ωrf) the correspondingB1 can be assigned. For the chosen diamond crystal low value of B1≈3.6µT at Rabi resonance was determined what makes it a convenient standard for DNP enhanced NMR spectroscopy which requires relatively small B1.

Mode spectra of magnetic and dielectric plasmon spheres obtained from Mie scattering and free oscillation theories

This paper presents Mie scattering theory as compared to rigorous electromagnetic theory of free oscillations in magnetic and electric plasmon spheres. It is shown that the maxima of Mie scattering and absorption spectra well correspond to resonance frequencies of plasmon modes occurring in dielectric and magnetic spheres, similarly as it takes place for ordinary dielectric resonator modes. Mie theory is well applicable to determine resonance frequencies and scattering parameters of spherical plasmons. However, this theory cannot be applied to determine intrinsic properties of modes induced in the object by the incident plane wave, like quality factors. On the contrary, rigorous electromagnetic theory of free oscillations allows one to determine the complex resonance frequency of each mode that can occur in a given object, and the corresponding quality factor accounting for various kind of losses, including medium and radiation losses. The advantage of the free oscillations theory, as shown in this paper, is in the determination of the quality factors of modes occurring in magnetic plasmon spheres made of a strongly dispersive magnetic medium.Graphical

Three-Body Dynamics of the a_{1}(1260) Resonance from Lattice QCD.

Resonant hadronic systems often exhibit a complicated decay pattern in which three-body dynamics play a relevant or even dominant role. In this work we focus on the a_{1}(1260) resonance. For the first time, the pole position and branching ratios of a three-body resonance are calculated from lattice QCD using one-, two-, and three-meson interpolators and a three-body finite-volume formalism extended to spin and coupled channels. This marks a new milestone for abinitio studies of ordinary resonances along with hybrid and exotic hadrons involving three-body dynamics.

Dielectric-Loaded Microwave Rectangular Waveguide and Higher Order Mode Resonator

Resonant transmission through a dielectric-loaded slot in a thick conducting diaphragm embedded in a rectangular waveguide is modeled using an analytical approximation based on the slot being small compared to a free-space wavelength. An image theory relates this problem to a metasurface consisting of an array of such slots. We demonstrate the existence of ordinary (Fabry–Perot) transmission resonances associated with the fundamental mode of the slot, as well as extremely narrowband (Fano) resonances involving the higher order modes in the slot. The theoretical predictions are confirmed through full-wave numerical simulation and by experimental measurement. Measurements on dielectrics consisting of multiple pieces reveal an additional set of sharp resonances, not predicted by our theory but verified by finite-element simulation. The results have potential application to sensors and material property measurement.

About theory of extended interaction klystron and drift space in the form of medium with complex permittivity

Purpose of this work is to construct a theory of extended interaction klystron with ordinary distributed resonators, but with a drift space in the form of medium with complex permittivity. Methods. For this, a hybrid of extended interaction klystron and an amplifier with a complex permittivity is considered in the framework of the weak signal approximation. Two types of configurations of a extended interaction klystron were considered: with two and three distributed resonators. For a two-resonator klystron with distributed interaction, two cases are considered: without reflections from the ends of distributed resonators and the case when the input binder is fully matched to the external transmission line, and for the second distributed resonator, the so-called condition of critical coupling of the “hot” resonator with the transmission line is satisfied. For a three-resonator klystron with distributed interaction, the case is considered without reflections from the ends of distributed resonators. Results and conclusion. According to the results of the developed theory of a weak signal in a extended interaction klystron with ordinary distributed resonators and a drift space with a complex dielectric constant, by choosing the parameters, it is possible to achieve a greater gain at a length that is shorter than in a conventional extended interaction klystron, all other things being equal. In addition, the presence of an intermediate distributed resonator makes it possible to increase the gain while maintaining the full length of the device.

Microscopic analysis of low-energy spin and orbital magnetic dipole excitations in deformed nuclei

A low-energy magnetic dipole $(M1)$ spin-scissors resonance (SSR) located just below the ordinary orbital scissors resonance (OSR) was recently predicted in deformed nuclei within the Wigner function moments (WFM) approach. We analyze this prediction using fully self-consistent Skyrme quasiparticle random phase approximation (QRPA) method. Skyrme forces SkM*, SVbas, and SG2 are implemented to explore SSR and OSR in $^{160,162,164}\mathrm{Dy}$ and $^{232}\mathrm{Th}$. Accuracy of the method is justified by a good description of $M1$ spin-flip giant resonance. The calculations show that isotopes $^{160,162,164}\mathrm{Dy}$ indeed have at 1.5--2.4 MeV (below OSR) ${I}^{\ensuremath{\pi}}K={1}^{+}1$ states with a large $M1$ spin strength ($K$ is the projection of the total nuclear moment to the symmetry $z$ axis). These states are almost fully exhausted by $pp[411\ensuremath{\uparrow},411\ensuremath{\downarrow}]$ and $nn[521\ensuremath{\uparrow},521\ensuremath{\downarrow}]$ spin-flip configurations corresponding to $pp[2{d}_{3/2},2{d}_{5/2}]$ and $nn[2{f}_{5/2},2{f}_{7/2}]$ structures in the spherical limit. So the predicted SSR is actually reduced to low-orbital ($l=2,3$) spin-flip states. Following our analysis and in contradiction with WFM spin-scissors picture, deformation is not the principle origin of the low-energy spin $M1$ states but only a factor affecting their features. The spin and orbital strengths are generally mixed and exhibit interference: weakly destructive in SSR range and strongly constructive in OSR range. In $^{232}\mathrm{Th}$, the $M1$ spin strength is very small. Two groups of ${I}^{\ensuremath{\pi}}={1}^{+}$ states observed experimentally at 2.4--4 MeV in $^{160,162,164}\mathrm{Dy}$ and at 2--4 MeV in $^{232}\mathrm{Th}$ are mainly explained by fragmentation of the orbital strength. Distributions of nuclear currents in QRPA states partly correspond to the isovector orbital-scissors flow but not to the spin-scissors one.

Coherence of resonant light-matter interaction in the strong-coupling limit

We explore the role of quantum fluctuations in the strong-coupling limit of the dissipative Jaynes–Cummings oscillator driven on resonance. For weak excitation, we derive analytical expressions for the spectrum and the intensity correlation function for the photons scattered by the two-state atom coupled to the coherently driven cavity mode. We do so by writing down a birth–death process adding the higher orders in the excitation strength needed to go beyond the pure-state factorization, following the method introduced in Carmichael (2008). Our results for the first and second-order correlation functions are complemented by the numerical investigation of the waiting-time distribution for the photon emissions directed sideways, and the comparison with ordinary resonance fluorescence. To close out our discussion, we increase the driving field amplitude and approach the critical point organizing a second-order dissipative quantum phase transition by depicting the excitation pathways in the intracavity field distribution for a finite system size.

Second-order coherence of fluorescence in multi-photon blockade

We calculate the second-order correlation function for the atomic fluorescence in the two-photon resonance operation of a driven dissipative Jaynes–Cummings oscillator. We employ a minimal four-level model comprising the driven two-photon transition alongside two intermediate states visited in the dissipative cascaded process, in the spirit of Shamailov et al. (2010). We point to the difference between the output of a JC oscillator exhibiting two-photon blockade and the scattered field of ordinary resonance fluorescence, and discuss the quantum interference effect involving the intermediate states, which is also captured in the axially transmitted light. The spectrum and intensity correlation of atomic emission explicitly reflect the particulars of the cascaded model.

Ordinary and extraordinary waves in hot nonextensive plasma

In this paper, a kinetic method based on particle velocity distribution function in the context of the nonextensive Tsallis statistics is presented for ordinary and extraordinary waves in a collisionless magnetized hot plasma. The components of the generalized dielectric tensor for perpendicular propagation in hot nonextensive plasma are derived in terms of generalized hypergeometric functions. The components are expressed as functions of different values of the nonextensive parameter q, which quantifies the degree of nonextensivity of the system. The dispersion relations of ordinary and extraordinary waves in hot plasma are obtained in the context of the nonextensive statistics. It is shown that in hot nonextensive plasma the generalized dispersion relations of these waves depend on q parameter, which means that the initial distribution function alters the properties of ordinary and extraordinary waves. For the hot nonextensive plasma, the ordinary and extraordinary wave experience resonances at cyclotron harmonics, whilst the upper hybrid resonance is eliminated due to thermal effects. However, cutoff frequencies shift to higher values as q parameter increases.

Dispersion control in a near-infrared subwavelength resonator with a tailored hyperbolic metamaterial.

We demonstrate experimentally and computationally an intricate cavity size dependence of the anomalous near-infrared mode spectrum of an ordinary optical resonator that is combined with a ZnO:Ga-based hyperbolic metamaterial (HMM). Specifically, we reveal the existence of a resonance in subwavelength-sized cavities and demonstrate control over the first-order cavity mode dispersion. We elaborate that these effects arise due to the HMM combining the mode dispersions of purely metallic and purely dielectric cavity cores into a distinct intermediate regime. By tailoring the HMM fill factor, this unique dispersion of a subwavelength resonator can be freely tuned between these two limiting cases.

Analytic stability boundaries for compressional and global Alfvén eigenmodes driven by fast ions. I. Interaction via ordinary and anomalous cyclotron resonances

Conditions for net fast ion drive are derived for beam-driven, sub-cyclotron compressional (CAE) and global (GAE) Alfvén eigenmodes, such as those routinely observed in spherical tokamaks such as NSTX(-U) and MAST. Both co- and counter-propagating CAEs and GAEs are investigated, driven by the ordinary and anomalous Doppler-shifted cyclotron resonance with fast ions. Whereas prior results were restricted to vanishingly narrow distributions in velocity space, broad parameter regimes are identified in this work which enable an analytic treatment for realistic fast ion distributions generated by neutral beam injection. The simple, approximate conditions derived in these regimes for beam distributions of realistic width compare well to the numerical evaluation of the full analytic expressions for fast ion drive. Moreover, previous results in the very narrow beam case are corrected and generalized to retain all terms in ω/ωci and |k∥/k⊥|, which are often assumed to be small parameters but can significantly modify the conditions of drive and damping when they are non-negligible. Favorable agreement is demonstrated between the approximate stability criterion, simulation results, and a large database of NSTX observations of cntr-GAEs.

Long-term output monitoring of hearing aids can be useful for the identification of intermittent faults

A rectangular cavity inside a two-dimensional sonic crystal was theoretically and experimentally characterized by examining its response to a cylindrical source emitting narrow-band filtered noise bursts with central frequencies ranging from 2 to 12 kHz. A broadband intensity resonance was observed for frequencies within the full band-gap region of the sonic crystal (5.5–6.5 kHz). Unlike ordinary resonances, this broadband resonance depends on the reflection properties of the sonic crystal forming the surrounding walls rather than on the geometry of the cavity.

Multiband Terahertz Self-Complementary Metasurface

A self-complementary metasurface is presented for application in multiband terahertz filters. The unit cell structures of the self-complementary metasurface consist of a combination of an ordinary Jerusalem cross and its complementary counterpart that resonates in the THz regime. The columnar repetition of ordinary and complementary resonator structures enables complementary spectral responses for incident waves with mutually orthogonal linear polarizations. The operating principles of the self-complementary metamaterial with the interaction between the juxtaposed ordinary and complementary Jerusalem crosses are explained using an equivalent circuit method and are confirmed with a full-wave electromagnetic simulation. The designed self-complementary metasurface functions as a selective bandstop filter (BSF) or bandpass filter (BPF) depending on the polarization states of the incident wave. The fabricated metasurface exhibits high polarization purity, exemplified by a polarization extinction ratio as high as 24 dB. The transmittance phases of the two orthogonally polarized waves have phase differences between -73° and 83° within a broad frequency range.

The Notched Stick, an ancient vibrot example.

An intriguing simple toy, commonly known as the Notched Stick, is discussed as an example of a “vibrot”, a device designed and built to yield conversion of mechanical vibrations into a rotational motion. The toy, that can be briefly described as a propeller fixed on a stick by means of a nail and free to rotate around it, is investigated from both an experimental and a numerical point of view, under various conditions and settings, to investigate the basic working principles of the device.The conversion efficiency from vibration to rotational motion turns out to be very small, or even not detectable at all, whenever the propeller is tightly connected to the stick nail and perfectly axisymmetrical with respect to the nail axis; the small effects possibly observed can be ascribed to friction forces. In contrast, the device succeeds in converting vibrations into rotations when the propeller center of mass is not aligned with the nail axis, a condition occurring when either the nail-propeller coupling is not tight or the propeller is not completely axisymmetrical relative to the nail axis. The propeller rotation may be induced by a process of parametric resonance for purely vertical oscillations of the nail, by ordinary resonance if the nail only oscillates horizontally or, finally, by a combination of both processes when nail oscillations take place in an intermediate direction. Parametric resonance explains the onset of rotations also when the weight of the propeller is negligible. In contrast with what is commonly claimed in the literature, the possible elliptical motion of the nail, due to a composition of two harmonic motions of the same frequency imposed along orthogonal directions, seems unnecessary to determine the propeller rotation.

Coherence of three-body Förster resonances in Rydberg atoms

We have observed recently the Stark-tuned three-body F\"orster resonances ${\rm 3}\times nP_{3/2} (|M|)\to nS_{1/2} +(n+1)S_{1/2} +nP_{3/2} (|M^{*} |)$ at long-range interactions of a few cold Rb Rydberg atoms [D.B.Tretyakov et al., Phys. Rev. Lett. 119, 173402 (2017)]. The three-body resonance appears at a different dc electric field with respect to the ordinary two-body resonance ${\rm 2}\times nP_{3/2} (|M|)\to nS_{1/2} +(n+1)S_{1/2} $ and corresponds to a transition when the three interacting atoms change their states simultaneously (two atoms go to the $S$ states, and the third atom remains in the $P$ state but changes its moment projection), with the negligible contribution of the two-body resonance to the population transfer. It thus has a Borromean character and represents an effective three-body operator, which can be used to directly control the three-body interactions in quantum simulations and quantum gates implemented with Rydberg atoms. In this paper we theoretically investigate the coherence of such three-body resonances and we show that high-contrast Rabi-like population oscillations are possible for the localized Rydberg atoms in a certain spatial configuration. This paves the way to implementing three-qubit quantum gates and quantum simulations based on three-body Rydberg interactions.

Low-mass dielectrons in pp, p–Pb and Pb–Pb collisions measured by the ALICE Experiment

Dielectrons produced in ultra-relativistic heavy-ion collisions at the LHC provide a unique probe of the system evolution as they are unperturbed by final-state interactions. The dielectron continuum is extremely rich in physics sources: on top of ordinary Dalitz and resonance decays of pseudoscalar and vector mesons, thermal black-body radiation is of particular interest as it carries information about the temperature of the hot and dense system created in such collisions. The dielectron invariant-mass distribution is furthermore sensitive to medium modifications of the spectral function of short-lived vector mesons that are linked to the potential restoration of chiral symmetry at high temperatures. Correlated electron pairs from semi-leptonic charm and beauty decays provide complementary information about the heavy-quark energy loss.

Parametric decay instability of an obliquely propagating ordinary wave in the electron cyclotron frequency range

The possibility of the low-power-threshold parametric decay of an obliquely propagating ordinary wave to an upper hybrid wave and a low-hybrid wave is analysed under conditions of nonmonotonic plasma density profile in a magnetic trap. The instability threshold and growth rate are derived explicitly. The analytical results are illustrated under the conditions typical of the ordinary mode fundamental electron cyclotron resonance heating harmonic experiments at the FTU tokamak.