S11 Resonance Research Articles

Circuit-level design principles for transmission-mode microwave impedance microscopy

A recently developed technique of transmission-mode microwave impedance microscopy (T-MIM) has greatly extended the capabilities of standard reflection-mode MIM to novel applications, such as the in operando study of nanoscale electro-acoustic devices. As is common for new techniques, systematic design principles for boosting sensitivity and balancing bandwidth are lacking. Here, we show numerically and analytically that the T-MIM signal is proportional to the reflection-mode voltage enhancement factor η of the circuit, as long as the output impedance of the local voltage source is properly treated. We show that this proportionality holds in the currently achievable “weak sampling” regime and beyond, for which we demonstrate a realistic path with commercially available superconducting components and critically coupled impedance matching networks. We demonstrate that for these next-generation designs, the sensitivity is generally maximized at a slightly different frequency from the unloaded S11 resonance, which can be explained by the maximum power transfer theorem.

Quantifying the second resonance effect in neutrino-Argon interaction using DUNE Near Detector

Heavy nuclear targets are used in neutrino oscillation experiments to boost the statistics of neutrino interactions. The complex nuclear environment contributes to the systematic uncertainty as the inevitable nuclear effects. Inadequate knowledge of the neutrino interaction with the nuclear target along with the imperfect reconstruction of neutrino energy seeds uncertainty in the cross-section. Uncertainty in the cross-section propagates as a systematic uncertainty in the determination of the neutrino oscillation parameters. For precision physics, future neutrino oscillation experiments will require understanding of the neutrino nucleus-interaction and neutrino energy reconstruction with a high level of accuracy. In this work, we aim to quantify the second resonance contributions to the neutrino interaction in Argon for reducing systematic uncertainties in the physics predictions for the DUNE Near Detector (ND). We present the results as the ratio distribution of dσdQ2 for Δ(1232) resonance and the extended analysis to the second resonance region P11(1440), D13(1520), and S11(1535). This inclusion shows a significant contribution to the total cross-section compared to the case where only the Δ(1232) resonance is considered.

Detection of Ethanol Concentration in Liquid Using a Double-Layered Resonator Operating at 5G-mm-Wave Frequencies

A new sensing technique for rapidly detecting ethanol concentration in aqueous solutions based on electromagnetic resonance is discussed. The sensor has two substrate layers and operates at 5G-mm-wave frequencies. An experimental study of the new resonator's configuration determines the sensor's sensitivity. During the measurements, 6 samples were modeled with varying amounts of ethanol concentration in the water. The results showed that S11 resonance moves linearly towards higher frequencies as the ethanol content increases. The resonant frequency shifted at 0.178 GHz per 10% increase in ethanol towards higher frequencies. As a result, the proposed 5G-mm-wave-sensing technique based on a replaceable sensing layer was proved to be suitable for rapid, accurate, and low-cost alcohol content detection in liquids.

Feasibility study of patch antenna for monitoring moisture content of made tea

This study aims to analyze the patch antenna for moisture content measurement of made tea. The patch antenna-based system uses an air gap between the ground plane and an electrically conductive patch. The tea sample is contained in the air gap. The patch antenna design has a resonance frequency of 5 GHz. The resonance frequency and S11 parameters are measured for tea samples in the moisture range of 2–10%. The resonance frequency of the patch antenna was observed to decrease with an increase in the moisture content of tea. However, the return loss of patch antenna was observed to increase with an increase in the moisture content of made tea. Linear model parameters were calculated for the prediction of the moisture content of tea leaves.

Embedded smart sensor dipole antennas for real-time damage assessment, humidity, and temperature monitoring in reinforced and non-reinforced concrete structures

AbstractIn this study, a dipole antenna is designed for real-time damage assessment, humidity, and temperature monitoring in reinforced and non-reinforced concrete structures. The antenna-based sensor is embedded into reinforced and non-reinforced concrete beams to assess electromagnetic measurements. Reflection parameter S11 in dB values and resonant frequencies of the embedded antenna are evaluated to detect damage, humidity, and temperature changes. The exploratory results show that as deformation increases in reinforced concrete, resonance frequency values decrease and S11 values increase. The load and resonance frequency values showed very close trends as deformation increases in the beam. In water content sensing experiments, the S11 in dB values of the antenna decrease as the humidity increases for concrete specimens while the resonance frequency values increase as the humidity increases for the reinforced concrete specimen. Elevated temperature sensing experimental results show that the resonance frequency values of the antenna decrease as the temperature of the specimen increases for concrete specimens while the S11 in dB values increase as the temperature of the specimen increases for reinforced concrete specimen.

Microplastic Detection in Soil and Water Using Resonance Microwave Spectroscopy: A Feasibility Study

A feasibility study of microplastic detection and quantification in soil and water using resonance microwave reflectometry is carried out using artificially created samples with a high volumetric concentration of microplastic with $50~\mu \text{m}$ -0.5mm particles size. A mathematical model expressing microplastic concentration in soil and water as a linear function of the measured S11 resonance frequency shift and relative permittivity contrast is developed and is found to be in an excellent agreement with the experimental data based on synthetic contaminated material samples. Next, this model is applied to find the best achievable theoretical resolution of microplastic concentration in the natural environment using microwave sensing technology, which is shown to be at around 100ppm (parts-per-million) level in the linear signal detection regime. It is demonstrated that the best achievable level of microplastic contaminant resolution depends on the sensor probe Q-factor and sensitivity of the microwave receiver. The bound for the achievable contaminant concentration resolution is found in the analytical form for high-Q resonance microwave sensors of arbitrary geometry. Even though several well-established protocols based on optical, infrared, and X-ray spectroscopy are currently being used for microplastic detection in the natural environment, microwave spectroscopy could offer additional benefits, especially for low-cost, real-time in-situ microplastic detection in diverse environmental conditions outside of the laboratory space.

Rectangular Cavity Sensor for Distinguishing Between Normal and High-Drivability-Index Gasolines

The Drivability Index (DI) of gasoline is a measure of fuel performance of engine operations. Therefore, distinguishing a gasoline of specific DI in advance is useful for improving engine efficiency and maintenance. We consider the problem of distinguishing between normal gasoline and HiDI (High DI) gasolines and propose an electromagnetic wave-based rectangular cavity sensor. For commercialization, it is designed to have a simple structure and basic resonance mode TM110 in the common frequency range of 5 GHz to 6 GHz. The proposed sensor has a simple structure of monopole radiating electromagnetic waves and a metal rectangular cavity containing gasoline samples. By considering one commercial normal gasoline sample of permittivity 2.157 and five HiDI gasoline samples of permittivity in the range of 2.018 to 2.218, we obtain 11.5 MHz resonance separation at room temperature to the closest HiDI sample from the simulation and 8 MHz resonance separation from the fabricated sensor experiment. To verify the feasibility of the fabricated sensor under temperature variation from 0°C to 20°C, we derived a simple linear distinction function of resonance frequency and S11 parameter and obtained a minimum 4.4MHz resonance separation. These results showed that the distinction performance for normal gasoline is robust to temperature variations. Furthermore, we showed that the distinction property is robust to design parameter errors, installation position variations and sensing time variations. These results show that the proposed sensor can be utilized effectively for distinguishing normal gasoline.

On the existence of N*(890) resonance in S11 channel of πN scatterings

Low-energy partial-wave πN scattering data is reexamined with the help of the production representation of partial-wave S matrix, where branch cuts and poles are thoroughly under consideration. The left-hand cut contribution to the phase shift is determined, with controlled systematic error estimates, by using the results of O(p3) chiral perturbative amplitudes obtained in the extended-onmass- shell scheme. In S11 and P11 channels, severe discrepancies are observed between the phase shift data and the sum of all known contributions. Statistically satisfactory fits to the data can only be achieved by adding extra poles in the two channels. We find that a S11 resonance pole locates at $$\sqrt {{z_r}} $$ = (0:895–0:081)–(0:164–0:023)i GeV, on the complex s-plane. On the other hand, a P11 virtual pole, as an accompanying partner of the nucleon bound-state pole, locates at $$\sqrt {{z_v}} $$ = (0:966–0:018) GeV, slightly above the nucleon pole on the real axis below threshold. Physical origin of the two newly established poles is explored to the best of our knowledge. It is emphasized that the O(p3) calculation greatly improves the fit quality comparing with the previous O(p2) one.

Nucleon resonances in πN → η′N and J/ψ → pp̄η′**Supported by National Natural Science Foundation of China (11347146, 11405222, 11105126, 11475227)

We are aiming to study the J/ψ → pp̄η′ decay in an isobar model and the effective Lagrangian approach on the basis of the coupling constants extracted from the πN → η′N reaction. After a careful exploration of the contributions of the S11(1535), P11(1710), P13(1900), S11(2090) and P11(2100) resonances, we conclude that either a subthreshold resonance or a broad P-wave state in the near threshold range seems to be indispensable to describe the present data of the πN → η′N. Furthermore, at least one broad resonance above η′N threshold is preferred. With this detailed analysis, we give the invariant mass spectrum and Dalitz plot of the J/ψ → pp̄η′ decay for the purpose of assisting the future detailed partial wave analysis. It is found that the J/ψ → pp̄η′ data are useful for disentangling the above or below threshold resonant contribution, though it still further needs the differential cross section data of πN → η′N to realize some of the resonant and non-resonant contribution.

Quasifree photoproduction ofηmesons off protons and neutrons

Differential and total cross sections for the quasifree reactions γp→ηp and γn→ηn have been determined at the MAMI-C electron accelerator by using a liquid deuterium target. Photons were produced via bremsstrahlung from the 1.5 GeV incident electron beam and energy tagged with the Glasgow photon tagger. Decay photons of the neutral decay modes η→2γ and η→3π0→6γ and coincident recoil nucleons were detected in a combined setup of the Crystal Ball and the TAPS calorimeters. The η-production cross sections were measured in coincidence with recoil protons, recoil neutrons, and in an inclusive mode without a condition on recoil nucleons, which allowed a check of the internal consistency of the data. The effects from nuclear Fermi motion were removed by a kinematic reconstruction of the final-state invariant mass and possible nuclear effects on the quasifree cross section were investigated by a comparison of free and quasifree-proton data. The results, which represent a significant improvement in statistical quality compared to previous measurements, agree with the known neutron-to-proton cross-section ratio in the peak of the S11(1535) resonance and confirm a peak in the neutron cross section, which is absent for the proton, at a center-of-mass energy W=(1670±5) MeV with an intrinsic width of Γ≈30 MeV.15 MoreReceived 12 April 2014Revised 19 June 2014DOI:https://doi.org/10.1103/PhysRevC.90.015205©2014 American Physical Society

Study of nucleon resonances in the photoproduction γp → K*+Λ

The mechanism of K* vector meson photoproduction off the proton target, γp → K*+Λ, is deeply studied by using an effective Lagrangian method. Based on the (t,s,u)-channel Born diagrams, we included higher resonance terms, i.e., S11(2090) and G17(2190), along with the D13(2080) and D15(2200), which are already considered in a previous theoretical analysis. The total and differential cross section are computed and we obtain quite precise results in comparison with the recent CLAS data.

Quasi-free photoproduction of η-mesons off 3He nuclei

Quasi-free photoproduction of η-mesons has been measured off nucleons bound in 3He nuclei for incident photon energies from the threshold region up to 1.4 GeV. The experiment was performed at the tagged photon facility of the Mainz MAMI accelerator with an almost 4π covering electromagnetic calorimeter, combining the TAPS and Crystal Ball detectors. The η-mesons were detected in coincidence with the recoil nucleons. This allowed a comparison of the production cross section off quasi-free protons and quasi-free neutrons and a full kinematic reconstruction of the final state, eliminating effects from nuclear Fermi motion. In the S11(1535) resonance peak, the data agree with the neutron/proton cross section ratio extracted from measurements with deuteron targets. More importantly, the prominent structure observed in photoproduction off quasi-free neutrons bound in the deuteron is also clearly observed. Its parameters (width, strength) are consistent with the expectations from the deuteron results. On an absolute scale the cross sections for both quasi-free protons and neutrons are suppressed with respect to the deuteron target pointing to significant nuclear final-state interaction effects.

η and η’ meson photoproduction on nucleons

Meson photoproduction on nucleons is considered within an approach based on a multipole analysis. The results of a decade-long theoretical investigation of η and η’ meson photoproduction on nucleons are discussed with the aim of gaining information about N resonances in experimental data. With an ongoing accumulation and refinement of experimental data, the number of known resonances used to analyze γp → ηp reactions was reduced from 12 to 6. However, S11(830) and D15(2150) resonances not included in the PDG compilation were found to be needed in those analyses. Precise measurements of differential cross sections of η meson photoproduction on protons carried out at the Mainz microtron offered the opportunity to specify the properties of S11(1535) resonance. The same theoretical approach has been used to analyze experimental data on the cross sections of γp → η’p reactions obtained by CLAS-2009 and Mainz collaborations. The description of the cross sections for this reaction with only nucleon resonances taken into account was found to be satisfactory up to the photon energy of 3700 MeV.

Nucleon Resonance Structure from Exclusive Meson Electroproduction with CLAS and CLAS12

The CLAS detector at Jefferson Lab is a unique instrument, which has provided the lionʼs share of the worldʼs data on meson photo- and electroproduction in the resonance excitation region. The electroexcitation amplitudes for the low-lying resonances P33(1232), P11(1440), D13(1520), and S11(1535) were determined over a wide range of Q2<5.0GeV2 in a comprehensive analysis of exclusive single-meson (π+n,π0p) reactions in the electroproduction off protons. Further, CLAS was able to precisely measure π+π−p electroproduction differential cross sections provided by the nearly full kinematic coverage of the detector. The electrocouplings of the P11(1440) and D13(1520) excited states are determined from the exclusive-π+π−p reaction. Consistent results on the electrocouplings from two-independent analyses (single- and double-pion electroproduction) have provided compelling evidence for the reliable extraction of the N⁎ electrocouplings. Preliminary results on the electrocouplings of the S31(1620), S11(1650), D33(1700), and P13(1720) states have recently become available. Theoretical analyses of these results have revealed that there are two major contributions to the resonance structure: a) an internal quark core and b) an external meson-baryon cloud. These CLAS results have had considerable impact on QCD-based studies on N⁎ structure and in the search for manifestations of the dynamical masses of the dressed quarks. Future CLAS12 N⁎ structure studies at high photon virtualities will considerably extend our capabilities in exploring the nature of confinement in baryons.

Investigation of near-threshold eta-meson production in the reaction π − p→ ηn

Differential and total cross sections for eta-meson production in the reaction π−p → ηn were measured within the experimental program eta-meson physics implemented in the pion channel of the synchrocyclotron of the Petersburg Nuclear Physics Institute (PNPI, Gatchina). These measurements were performed at incident-pion momenta (700, 710, 720, and 730 MeV/c) in the vicinity of the threshold for the process under study by using the neutral-meson spectrometer designed and created at the Meson Physics Laboratory of PNPI. It is shown that, in the immediate vicinity of the threshold (685 MeV/c), the process of eta-meson production proceeds predominantly via S11(1535)-resonance formation followed by the decay S11(1535) → ηn (the respective branching fraction is Br ≈ 60%), but that, as the momentum of incident pions increases, the role of the D wave becomes ever more important. A detailed analysis of this effect indicates that it is due to the increasing contribution of the D13(1520) resonance. Although the branching fraction of the decay of this resonance through the ηn channel is assumed to be very small (BR ≈ 0.24%), the effect is enhanced owing to the interference between the D wave and the dominant resonance S11(1535).

Search for η-mesic nuclei in the reaction d + C at JINR

Results of a search for quasi-bound states of the η-meson and a target nucleus obtained during several years using the internal target at the Nuclotron d-beam are presented. Formation of η-mesic nuclei was studied in the reaction d + C in the energy interval 1.5 to 2.2 GeV/nucl. Decay products of S11 resonances excited by η-mesons captured by nucleons in the nuclear target have been analyzed. Measurements were performed with a scintillation spectrometer SCAN. Analysis of obtained data is presented.

Covariant model for theγN→N(1535)transition at high momentum transfer

A relativistic constituent quark model is applied to the $\ensuremath{\gamma}N\ensuremath{\rightarrow}N(1535)$ transition. The $N(1535)$ wave function is determined by extending the covariant spectator quark model, previously developed for the nucleon, to the ${S}_{11}$ resonance. The model allows us to calculate the valence quark contributions to the $\ensuremath{\gamma}N\ensuremath{\rightarrow}N(1535)$ transition form factors. Because of the nucleon and $N(1535)$ structure the model is valid only for ${Q}^{2}&gt;2.3\text{ }\text{ }{\mathrm{GeV}}^{2}$. The results are compared with the experimental data for the electromagnetic form factors ${F}_{1}^{*}$ and ${F}_{2}^{*}$ and the helicity amplitudes ${A}_{1/2}$ and ${S}_{1/2}$, at high ${Q}^{2}$.

Pion Electro-Production in the Region of Low-Lying P11 and S11 Resonances

A coupled-channel approach incorporating quasi-bound quark-model states has been used to calculate pion-nucleon scattering amplitudes in the P11 and S11 partial waves and the corresponding pion electro-production amplitudes. The method allows for the extraction of the resonant part of the amplitudes even in the presence of different decay channels and a strong mixing of neighbouring resonances. We demonstrate the important role of the pion cloud at large distances, as opposed to the short-distance behaviour governed by the quark core.

Conformal symmetry and light flavor baryon spectra

The degeneracy among parity pairs systematically observed in the N and Delta spectra is interpreted to hint on a possible conformal symmetry realization in the light flavor baryon sector in line with AdS_5/CFT_4. The case is made by showing that all the observed N and Delta resonances with masses below 2500 MeV distribute fairly well each over the first levels of a unitary representation of the conformal group, a representation that covers the spectrum of a quark-diquark system, placed directly on the AdS_5 cone, conformally compactified to R^1*S^3. The free geodesic motion on the S^3 manifold is described by means of the scalar conformal equation there, which is of the Klein-Gordon type. The equation is then gauged by the "curved" Coulomb potential that has the form of a cotangent function. Conformal symmetry is not exact, this because the gauge potential slightly modifies the conformal centrifugal barrier of the free geodesic motion. Thanks to this, the degeneracy between P11-S11 pairs from same level is relaxed, while the remaining states belonging to same level remain practically degenerate. The model describes the correct mass ordering in the P11-S11 pairs through the nucleon spectrum as a combined effect of the above conformal symmetry breaking, on the one side, and a parity change of the diquark from a scalar at low masses, to a pseudoscalar at higher masses, on the other. The quality of the wave functions is illustrated by calculations of realistic mean-square charge radii and electric charge form-factors on the examples of the proton, and the protonic P11(1440), and S11(1535) resonances. The scheme also allows for a prediction of the dressing function of an effective instantaneous gluon propagator from the Fourier transform of the gauge potential. We find a dressing function that is finite in the infrared and tends to zero at infinity.

Study of nucleon resonances in a chiral quark model via η productions

In this report we investigate η-meson productions on the proton via electromagnetic and hadron probes in a chiral quark model approach. The observables, such as, differential cross section and beam asymmetry for the two productions are calculated and compared with the experiment. The five known resonances S11(1535), S11(1650), P13(1720), D13(1520), and F15(1680) are found to be dominant in the reaction mechanisms in both channels. Significant contribution from a new S11 resonances are deduced. For the so-called “missing resonances”, no evidence is found within the investigated reactions. The partial wave amplitudes for π−p → ηn are also presented.