Radial Excitation Research Articles

Radial vortex core oscillations in Bose-Einstein condensates

Dilute ultracold quantum gases form an ideal and highly tunable system in which superuidity can be studied. Recently quantum turbulence in Bose-Einstein condensates was reported [PRL 103, 045310 (2009)], opening up a new experimental system that can be used to study quantum turbulence. A novel feature of this system is that vortex cores now have a finite size. This means that the vortices are no longer one dimensional features in the condensate, but that the radial behaviour and excitations might also play an important role in the study of quantum turbulence in Bose-Einstein condensates. In this paper we investigate these radial modes using a simplified variational model for the vortex core. This study results in the frequencies of the radial modes, which can be compared with the frequencies of the thoroughly studied Kelvin modes. From this comparison we find that the lowest (l=0) radial mode has a frequency in the same order of magnitude as the Kelvin modes. However the radial modes still have a larger energy than the Kelvin modes, meaning that the Kelvin modes will still constitute the preferred channel for energy decay in quantum turbulence.

Probing a new strongly interacting sector via composite diboson resonances

Diphoton resonance was a crucial discovery mode for the 125 GeV SM Higgs boson at the LHC. This mode or the more general diboson modes may also play an important role in probing for new physics beyond the SM. In this paper, we consider the possibility that a diphoton resonance is due to a composite (pseudo)scalar boson, whose constituents are either new hyperquarks Q or scalar hyperquarks tilde{Q} confined by a new hypercolor force at a confinement scale Lambda_h. Assuming the mass m_Q (or m_{tilde Q}) >> Lambda_h, a diphoton resonance could be interpreted as either a Q bar{Q} state eta_Q with J^{PC} = 0^{-+} or a tilde{Q} tilde{Q}^dagger state eta_{tilde Q} with J^{PC}=0^{++}. For the Q bar{Q} scenario, there will be a spin-triplet partner psi_Q which is slightly heavier than eta_Q due to the hyperfine interactions mediated by hypercolor gluon exchange; while for the tilde{Q} tilde{Q}^dagger scenario, the spin-triplet partner chi_{tilde Q} arises from higher radial excitation with nonzero orbital angular momentum. We consider productions and decays of eta_Q, eta_{tilde Q}, psi_Q, and chi_{tilde Q} at the LHC using the NRQCD factorization approach. We discuss how to test these scenarios by using the DY process and the forward dijet azimuthal angular distributions to determine the J^{PC} quantum number of the diphoton resonance. Constraints on the parameter space can be obtained by interpreting some of the small diphoton excesses reported by the LHC as the composite scalar or pseudoscalar of the model. Another important test of the model is the presence of a nearby hypercolor-singlet but color-octet state like the eta^8_Q or eta^8_{tilde Q}, which can also be constrained by dijet or monojet+monophoton data. Both possibilities of a large or small width of the resonance can be accommodated, depending on whether the hyper-glueball states are kinematically allowed in the final state or not.

Understanding the newly observed Ωc states through their decays

The strong and radiative decay properties of the low-lying $\Omega_c$ states are studied in a constituent quark model. We find that the newly observed $\Omega_c$ states by the LHCb Collaboration can fit in well the decay patterns. Thus, their spin-parity can be possibly assigned as the following: (i) The $\Omega_c(3000)$ has $J^P=1/2^-$ and corresponds to the narrow $1P$ mixed state $|1^2P_{\lambda}\frac{1}{2}^-\rangle_1$, its partner $|1^2P_{\lambda}\frac{1}{2}^-\rangle_2$ should be a broad state with a width of $\sim 100$ MeV. (ii) The $\Omega_c(3050)$ and $\Omega_c(3066)$ can be assigned to be two $J^P=3/2^-$ states, $|1^4P_{\lambda}\frac{3}{2}^-\rangle$ and $|1^2P_{\lambda}\frac{3}{2}^-\rangle$, respectively. (iii) The $\Omega_c(3090)$ can be assigned as the $|1^4P_{\lambda}\frac{5}{2}^-\rangle$ state with $J^P=5/2^-$. (iv) The $\Omega_c(3119)$ might correspond to one of the two $2S$ states of the first radial excitations, i.e. $|2^2S_{\lambda\lambda}\frac{1}{2}^+\rangle$ or $|2^4S_{\lambda\lambda}\frac{3}{2}^+\rangle$.

On the nature of the newly discovered Ω states

The mass and residue of the ground-state, as well as the first orbital and radial excitations of the heavy baryons with Q being b or c quark, for both and are calculated by means of the QCD two-point sum rule method using the general forms for the interpolating currents. In the calculations the quark, gluon and mixed vacuum condensates up to ten dimensions are taken into account. We compare our results for the masses of and baryons with the existing predictions of other theoretical works. Our results for the charmed baryons are confronted with the experimental data of the LHCb Collaboration to understand the nature of the recently observed narrow resonances. The predictions for the masses of the baryons with the same quantum numbers may shed light on future experimental searches for the corresponding bottom baryons.

Influence of a variable Rayleigh scattering-loss coefficient on the light backscattering in multimode optical fibers.

The recently developed diffraction technique of analytical investigation of the Rayleigh backscattering produced by an incident fundamental mode in a multimode optical fiber with an arbitrary refractive index profile is supplemented by taking into account the Rayleigh scattering-loss coefficient, which could be variable within the fiber cross section. The relative changes in various radial and azimuthal modes' excitation levels, due to some typical radial dependences of this coefficient, are computed for the quadratic- and step-index fibers. It is stated that the excitation efficiency could either rise or decay for different modes. The effect of the variable Rayleigh scattering-loss coefficient is shown to be more noticeable in the fibers with a quadratic refractive index profile, whereas it is negligible in actual multimode step-index fibers.

Higher hybrid bottomonia in an extended potential model

Using our extension of the quark potential model to hybrid mesons that fits well with the available lattice results, we now calculate the masses, radii, wave functions at the origin, leptonic and two-photon decay widths, and $E1$ and $M1$ radiative transitions for a significant number of bottomonium mesons. These mesons include both conventional and hybrid ones with radial and angular excitations. Our numerical solutions of the Schr\"odinger equation are related to QCD through the Born-Oppenheimer approach. Relativistic corrections in masses and decay widths are also calculated by applying the leading-order perturbation theory. The calculated results are compared with available experimental data and the theoretical results by other groups. We also identify the states of $\mathrm{\ensuremath{\Upsilon}}(10860)$, $\mathrm{\ensuremath{\Upsilon}}(11020)$, and ${Y}_{b}(10890)$ mesons by comparing their experimental masses and decay widths to our results.

Two-dimensional mass spectrometry in a linear ion trap, an in silico model.

Two-dimensional mass spectrometry (2D MS) is a technique that correlates precursor and product ions in a sample without requiring prior ion isolation. Until now, this technique has only been implemented on Fourier transform ion cyclotron resonance mass spectrometers. By coupling 2D MS techniques in linear ion traps (LITs) with a mass analyser with a fast duty cycle (e.g. time-of-flight), data-independent tandem mass spectrometry techniques can be compatible on a liquid chromatography (LC) or gas chromatography (GC) timescale. The feasibility of 2D MS in a LIT is explored using SIMION ion trajectory calculations. By applying stored waveform inverse Fourier transform techniques for radial excitation on a LIT, the sizes of ion clouds were found to be modulated according to the ions' resonant frequencies in the LIT. By simulating a laser-based fragmentation at the centre of the LIT after the radius modulation step, product ion abundances were found to be modulated according to the resonant frequency of their precursor. A 2D mass spectrum could be obtained using the results from the simulation. This in silico model shows the feasibility of 2D MS on a LIT. 2D MS in a LIT allows for tandem mass spectrometry without ion isolation. Copyright © 2017 John Wiley & Sons, Ltd.

Charged rotating black holes in Einstein-Maxwell-Chern-Simons theory with a negative cosmological constant

We consider rotating black hole solutions in five-dimensional Einstein-Maxwell-Chern-Simons theory with a negative cosmological constant and a generic value of the Chern-Simons coupling constant $\lambda$. Using both analytical and numerical techniques, we focus on cohomogeneity-1 configurations, with two equal-magnitude angular momenta, which approach at infinity a globally AdS background. We find that the generic solutions share a number of basic properties with the known Cvetic, L\"u and Pope black holes which have $\lambda=1$. New features occur as well, for example, when the Chern-Simons coupling constant exceeds a critical value, the solutions are no longer uniquely determined by their global charges. Moreover, the black holes possess radial excitations which can be labelled by the node number of the magnetic gauge potential function. Solutions with small values of $\lambda$ possess other distinct features. For instance, the extremal black holes there form two disconnected branches, while not all near-horizon solutions are associated with global solutions.

Model validation for radial electric field excitation during L–H transition in JFT-2M tokamak

In this paper, we elaborate the electric field excitation mechanism during the L–H transition in the JFT-2M tokamak. Using time derivative of the Poisson’s equation, models of the radial electric field excitation is examined. The sum of the loss-cone loss current and the neoclassical bulk viscosity current is found to behave as the experimentally evaluated radial current that excites the radial electric field. The turbulent Reynolds stress only plays a minor role. The wave convection current that produces a negative current at the edge can be important to explain the ambipolar condition in the L-mode.

Bubble-induced noise and vibration in cylindrical shell filled with liquid nitrogen

Bubble-induced vibration is a very crucial aspect in some critical systems like laser interferometer gravitational-wave observatory. Recently, laser interferometer gravitational-wave observatory detected the gravitational wave produced due to the merger of two black holes. To detect the other universe collision event due to other binary pairs like neutron stars, black holes or combination, the sensitivity of the detector should be very high. The sensitivity depends on the reduction of the noise present in the detector system / components. Liquid nitrogen cryopump is also one of the sources for the noise. This noise has been produced due to the bubble structure interaction. The present work analyzes the bubble generated noise spectrum level and its acoustic effect due to induced vibration. The spectrum levels considering force, acceleration, velocity, and displacement effect have been studied in detail for a thin annular fluid (LN2) filled cylindrical shell. It is assumed that the structure of cylindrical shell is homogeneous as well as isotropic. The noise level generated due to radial force excitation resulting from bubble collision has been found to be in the range of −85 dB to −45 dB at a lower resonance frequency.

Radial excitations of current-carrying vortices

We report on the existence of a new type of cosmic string solutions in the Witten model with U(1)×U(1) symmetry. These solutions are superconducting with radially excited condensates that exist for both gauged and ungauged currents. Our results suggest that these new configurations can be macroscopically stable, but microscopically unstable to radial perturbations. Nevertheless, they might have important consequences for the network evolution and particle emission. We discuss these effects and their possible signatures. We also comment on analogies with non-relativistic condensed matter systems where these solutions may be observable.

Nonlinear aeroelastic flutter and dynamic response of composite laminated cylindrical shell in supersonic air flow

Aeroelastic flutter characteristics and dynamic response of a composite laminated circular cylindrical shell under combined action of radial harmonic excitation, compressive in-plane force and aerodynamic pressure are studied in this paper. The first-order piston theory is employed to model the aerodynamics pressure. Partial differential equations governing the vibrations of the cylindrical shell are derived based on the Hamilton’s principle and the Donnell’s nonlinear shell theory. The Galerkin’s method is adopted to discretize the partial differential governing equations to a set of nonlinear ordinary differential equations. The four-dimensional averaged equation is obtained by applying the method of multiple scales under the case of 1:2 internal resonance. The critical free stream static pressure originating flutter of the shell is determined by solving the eigenvalue problem. The phase portrait and time history diagrams are presented to demonstrate the character of the limit cycle oscillation of the shell. The influence of different geometrical parameters, such as the radius, length and thickness of the shell, on the flutter characteristics of the composite laminated circular cylindrical shell are discussed in details. The influences of the amplitudes of the in-plane and transverse excitations on the frequency–response curves and force-response curves are also investigated.

The global Higgs as a signal for compositeness at the LHC

The radial excitation of the global symmetry-breaking vacuum in composite Higgs models, called the “global Higgs”, has been recently a focus of investigation. In this paper we study the prospects for detecting this composite scalar at the 13 TeV LHC. We compute the global Higgs production rates and estimate the discovery potential of a global Higgs decaying into top quark pairs and into Higgs and electroweak gauge bosons with subsequent hadronic decays. The global Higgs may also decay into fermion resonances such as top partners, providing a new window into compositeness. We show that top partner jets can be effectively unresolved in some regions of the parameter space. Such “boosted top partner” signatures would deserve the development of dedicated substructure analyses.

Analysis of Radial Excitations of Octet Baryons in QCD Sum Rules

Using the QCD sum rules method, we estimate the mass and residues of the first radial excitations of octet baryons. The contributions coming from the ground state baryons are eliminated by constructing the linear combinations of the sum rules corresponding to different Lorentz structures. Our predictions of the masses of the first radial excitations of octet baryons are in good agreement with the data.

Mass spectra and Regge trajectories of , , and baryons**Supported in part (A. K. Rai) by DST, India (SERB Fast Track Scheme SR/FTP/PS-152/2012)

We calculate the mass spectra of the singly charmed baryons (, , and ) using the hypercentral constituent quark model (hCQM). The hyper color Coulomb plus linear potential is used to calculate the masses of positive (up to ) and negative (up to ) parity excited states. The spin-spin, spin-orbital and tensor interaction terms are also incorporated for mass spectra. We have compared our results with other theoretical and lattice QCD predictions for each baryon. Moreover, the known experimental results are also reasonably close to our predicted masses. By using the radial and orbital excitation, we construct Regge trajectories for the baryons in the (n, M2) plane and find their slopes and intercepts. Other properties of these baryons, like magnetic moments, radiative transitions and radiative decay widths, are also calculated successfully.

X(4140) , X(4270) , X(4500) , and X(4700) and their csc¯s¯ tetraquark partners

In the simple color-magnetic interaction model, we investigate possible ground $cs\bar{c}\bar{s}$ tetraquark states in the diquark-antidiquark basis. We use several methods to estimate the mass spectrum and discuss possible assignment for the $X$ states observed in the $J/\psi\phi$ channel. We find that assigning the Belle $X(4350)$ as a $0^{++}$ tetraquark is consistent with the tetraquark interpretation for the $X(4140)$ and $X(4270)$ while the interpretation of the $X(4500)$ and $X(4700)$ needs orbital or radial excitation. There probably exist several tetraquarks around 4.3 GeV that decay into $J/\psi\phi$ or $\eta_c\phi$.

Leading-twist distribution amplitudes of scalar and vector mesons

A symmetry-preserving truncation of the two-body light-quark bound-state problem in relativistic quantum field theory is used to calculate the leading-twist parton distribution amplitudes (PDAs) of scalar systems, both ground-state and radial excitations, and the radial excitations of vector mesons. Owing to the fact that the scale-independent leptonic decay constant of a scalar meson constituted from equal-mass valence-constituents vanishes, it is found that the PDA of a given scalar system possesses one more zero than that of an analogous vector meson. Consequently, whereas the mean light-front relative momentum of the valence-constituents within a vector meson is zero, that within a scalar meson is large, an outcome which hints at a greater role for light-front angular momentum in systems classified as $P$-wave in quantum mechanical models. Values for the scale-dependent decay constants of ground-state scalar and vector systems are a by-product of this analysis, and they turn out to be roughly equal, viz. $\simeq 0.2\,$GeV at an hadronic scale. In addition, it is confirmed that the dilation characterising ground-state PDAs is manifest in the PDAs of radial excitations too. The impact of $SU(3)$-flavour symmetry breaking is also considered. When compared with pseudoscalar states, it is a little stronger in scalar systems, but the size is nevertheless determined by the flavour-dependence of dynamical chiral symmetry breaking and the PDAs are still skewed toward the heavier valence-quark in asymmetric systems.

Influence of web plate holes on the radiation noise characteristics of wheels of the high speed train

The finite element model of wheels without holes was established to compute its free modal and compare with the experimental result. The relative error was controlled within 5 %, which indicated that the finite element model in this paper was reliable. Based on the finite element and geometric model, the acoustic boundary element model of wheels was established to compute the radiation noise of wheels under the action of radial and normal excitation forces. Results showed that the change trend and value of radiation noises of wheels were similar under the action of two kinds of excitation forces when the analyzed frequency was lower than 1421 Hz. However, the radiation noise of wheels under the action of two kinds of excitation forces was significantly different and presented obvious directivity in three planes with the increase of the analyzed frequency. Then, models of wheels with 5, 6, 9 and ellipse holes were established to compute radiation noises and conduct comparative analysis. Results showed that the radiation noise of wheels with 6 holes was relatively minimum under radial and normal excitations and did not decrease with the increase of the hole number. The radiation noise of wheels with circular holes made certain improvement, compared with the radiation noise of wheels with ellipse holes. Distribution curves for the directivity of radiation noises of various wheels were highly symmetrical in the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>Z</mml:mi></mml:math> plane and radiation noises had relatively maximum in the position of multiples of 30°. The curve for the directivity of radiation noises of wheels with 5 holes was clearly different from that of other structures in the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>Y</mml:mi></mml:math> plane.

Density distributions in the B meson

We report on a two-flavor lattice QCD study of the axial, charge and matter distributions of the $B$ meson and its first radial excitation. As our framework is the static limit of Heavy Quark Effective Theory (HQET), taking their Fourier transform gives access to several form factors at the kinematical point $q^2=0$. Moreover they provide some useful information on the nature of an excited state, i.e. a radial excitation of a quark-antiquark bound state or a multihadron state.

Decay constants in soft wall AdS/QCD revisited

Phenomenological AdS/QCD models, like hard wall and soft wall, provide hadronic mass spectra in reasonable consistency with experimental and (or) lattice results. These simple models are inspired in the AdS/CFT correspondence and assume that gauge/ gravity duality holds in a scenario where conformal invariance is broken through the introduction of an energy scale. Another important property of hadrons: the decay constant, can also be obtained from these models. However, a consistent formulation of an AdS/QCD model that reproduces the observed behavior of decay constants of vector meson excited states is still lacking. In particular: for radially excited states of heavy vector mesons, the experimental data lead to decay constants that decrease with the radial excitation level. We show here that a modified framework of soft wall AdS/QCD involving an additional dimensionfull parameter, associated with an ultraviolet energy scale, provides decay constants decreasing with radial excitation level. In this version of the soft wall model the two point function of gauge theory operators is calculated at a finite position of the anti-de Sitter space radial coordinate.