Radiative Widths Research Articles

Validity analysis of γ-ray strength function models for radiative capture reactions of heavy nuclei

Accurate simulation of radiative capture reactions (RCRs) requires precise modeling of [Formula: see text]-ray strength functions (GSF). Various GSF models exist but need normalization based on experimental total radiative width (TRW) data. This study found that current normalization methods fail for neutron-induced RCRs in [Formula: see text]U and [Formula: see text]Th nuclei. In this regard, re-normalization values are proposed in order to improve model consistency at low energies. The standard Lorentzian (SLO) model fits experimental data best with minimal normalization.

New measurement of the Hoyle state radiative transition width

The radiative decay of the Hoyle state serves as the gateway to the production of heavier elements in a stellar environment. Here, we present an exclusive measurement of electric quadruple (E2) transitions of the Hoyle state to the ground state of 12C through the 12C(p, p′γγ)12C reaction. A triple coincidence measurement yields the radiative branching ratio Γrad/Γ = 4.01 (30) × 10−4. This result was corroborated by an independent experiment based on the complete kinematical measurement via12C(p, p′)12C reaction, yielding a consistent result of Γrad/Γ = 4.04 (30) × 10−4. Combining our results with the currently adopted values of Γπ(E0)/Γ and Γπ(E0), the radiative width of the Hoyle state is determined to be 3.75 (40) × 10−3 eV. It is important to note that our finding do not align with a recently reported 34% increase in the radiative decay width of the Hoyle state but is consistent with the currently accepted value.

Spectra and decay properties of higher lying BC meson states

In this work, the spectra and decay properties of [Formula: see text] mesons [Formula: see text]) have been investigated using a nonrelativistic potential model incorporating corrections from LQCD. The nonrelativistic Schrödinger wave equation is solved numerically using the Matrix Numerov Method. Using the obtained masses and wave functions, decay widths, lifetime, branching ratios and radiative decay widths are computed for the [Formula: see text] system. Influence of the bound state effect on decay width of [Formula: see text] mesons is also analyzed. We compare the obtained results with the experimental data and with other theoretical models.

Cascade Ξ0 baryon spectroscopy in the relativistic framework of an independent quark model

The spectroscopy of Ξ0 is performed within the relativistic framework of independent quark model. The equal mixture of scalar and vector components in the potential having Martin-like form is considered for the confinement. With the suitable potential parameters for Ξ0, mass spectra for high radial and orbital excitation is calculated. The experimentally observed values of the ground-state magnetic moment, branching ratios, and asymmetry parameters for radiative weak decays, Ξ0→Λ0+γ0 and Ξ0→Σ0+γ0 are obtained to validate the model. The spin parity of experimentally known resonances like Ξ(1530), Ξ(1820), and Ξ(2030) are confirmed through the Regge trajectories in (J,M2) plane. The spin parity of Ξ(1950), Ξ(2130), and Ξ(2250) are predicted using those Regge trajectories. The radiative decay width and magnetic moment of first resonance is also predicted. Published by the American Physical Society 2024

Bottomonia in quark-antiquark confining potential

This paper comprehensively explores bottomonia mass spectra and their decay properties by solving the non-relativistic Schrodinger wave equation numerically with an approximate quark-antiquark potential form. We also incorporate spin-dependent terms—spin-spin, spin-orbit, and tensor terms to remove mass degeneracy and to obtain excited states (nS, nP, nD, nF, n = 1, 2, 3, 4, 5) mass spectra. Using the Van Royen—Weisskopf formula, we investigate leptonic decay constants, di-leptonic, di-gamma, tri-gamma, di-gluon decay widths and incorporate first-order radiative corrections. We also computed radiative transition widths, which provide better insight into the non-perturbative aspects of QCD. The states ϒ(10750), ϒ(10860), ϒ(11020) are analyzed as pure states 33 D 1, 53 S 1 and 43 D 1, respectively. The present mass spectroscopy and decay properties results align with available experimental values and other theoretical predictions. Our results may provide better insight into upcoming experimental information in the near future.

M1 radiative and spin-nonflip ππ transitions of Bc states in the Cornell potential model

In this paper, we mainly predict the rates of M1 radiative and spin-nonflip ππ transitions of the Bc-meson under the nonrelativistic Cornell potential model with a screening potential effect. We employ the numerical wave function to determine the M1 radiative transition widths of Bc excited states and utilize the Kuang-Yan proposed method for the spin-nonflip ππ transitions among Bc states. Our theoretical results are valuable for studying the M1 radiative and spin-nonflip ππ transition processes of Bc states in experiments. Published by the American Physical Society 2024

Production of Xb via radiative transition of ϒ(10753)

We studied the radiative transitions between the ϒ(10753), the S−D mixed state of the ϒ(4S) and ϒ1(3D13), and the Xb, the heavy quark flavor symmetry counterpart of the X(3782) in the bottomonium sector. The radiative transition was assumed to occur through the intermediate bottom mesons, including P-wave B1(′) mesons as well as the S-wave B(*) ones. The consideration of the B1(′) mesons leads to the couplings to be in S-wave, and hence enhances the contributions of the intermediate meson loops. The radiative decay width for the ϒ(10753)→γXb is predicted to be order of 10 keV, corresponding to a branching fraction of 10−4. Based on the theoretical results, we strongly suggest to search for the Xb in the e+e−→γXb with Xb→ππχb1 near s=10.754 GeV, and it is hoped that the calculations here could be tested by the future Belle II experiments. Published by the American Physical Society 2024

A theoretical and numerical analysis of solar chimney in multi-storey atrium building

Current research efforts on solar chimney are much on those configurations with single space or single vent, hampering its applications in complex buildings. To expand its implementation, the viability of solar chimney in multi-storey atrium buildings was explored numerically and theoretically. It was known that its natural ventilation performance can fulfil the WHO requirements (i.e., 6 air change per hour, ACH) even under low solar radiation of 200 W/m2 if it is appropriately designed, such as cavity gap (d), cavity height (Hc), solar radiation (Q), and window width (W). Its natural ventilation rate was found to be positively linear to the exponential form of the analyzed factors in this study, including cavity gap (d0.63∼0.69), cavity height (Hc0.59∼0.60), solar radiation (Q0.42∼0.43), and window width (W0.14∼0.20). The impacts of cavity gap and solar radiation are relatively weaker for big space such as atrium than those scenarios with single-space ventilation in the literature. The volume of the connected space was found to affect its natural ventilation performance, where the obtained ventilation rate of 4-storey is averagely 5.1 % lower than those of 3-storey buildings. A theoretical model was developed and experimentally validated, for the first time, to predict the natural ventilation rate of solar chimney when it is applied to the atrium with multiple air inlets. It was also noticed that the same theoretical model can be applied to the atrium buildings with odd and even storeys, but the area coefficients are different. The research outcomes of this study confirm the viability of solar chimney in complex buildings and offer a theoretical foundation for its implementation.

Role of electromagnetic interactions in the X(3872) and its analogs

We investigate the role of the electromagnetic interaction in the formation and decay of the X(3872). The binding properties of the X(3872) are studied by assuming the molecular nature and considering the S−D wave mixing, isospin breaking, and coupled channel effects, and in particular the correction from the electromagnetic interaction. The radiative decays can better reflect the difference between the charged and neutral DD¯* components, since the electromagnetic interaction explicitly breaks the isospin symmetry. We further study the radiative decay widths with the obtained wave functions for different DD¯* channels. We also explore other similar hidden-charm molecular states. The electromagnetic interaction can make the molecule tighter. Our result of the radiative decay width for X(3872)→γJ/ψ is in agreement with the experiment. The branching ratio Rγψ is less than 1 in our framework, which supports the Belle and BESIII measurements. Published by the American Physical Society 2024

Study of characteristics elementary atomic processes in the neon-like multicharged ions plasma within an energy approach

We present the theoretical foundations of an advanced relativistic approach to computing the main energy, spectral characteristics of radiative-collisional processes in the plasma (in particular, the Debye plasma) of atomic as the example, neon-like) ions with simultaneous, quantitatively consistent consideration of the complex relativistic, interelectron exchange-correlation and plasma environment effects. The approach is based on the combination of a relativistic energy approach (S-matrix Gell-Mann and Low formalism), the relativistic gauge-invariant many-body perturbation theory with optimized Dirac-Fock-Sturm and Debye-Hückel approximations with accounting for the plasma environment effects with possible generalization on the presence of an additional external electromagnetic field. The fundamental point of our approach is the selection of the optimized Dirac-Fock-Sturm zeroth approximation and application of the consistent procedure for constructing a one-quasiparticle representation (basis’s of relativistic wave functions) in compliance with the principle of gauge invariance, in particular, by minimizing a gauge-noninvariant contributions to the radiative widths of the atomic (ionic) levels due to the complex exchange-correlation effects. The electron-ion collision strength and the dioelect5ron capture rate etc are determined within the presented theory.

Direct immersion single-drop microextraction combined with fluorescence detection using an optical probe. Application for highly sensitive determination of rhodamine 6G

The use of an optical probe for fluorescence detection combined with direct immersion single-drop microextraction has been demonstrated as an innovative approach. The optical probe served both as a drop holder for extractant and as a measuring device which made it possible to eliminate the use of cuvettes. A laser and a light emitting diode (LED) were tested as possible light sources. Both of them showed comparable results. However, given the much smaller half-band width of the laser radiation, its use has proven to be preferable since background correction can be eliminated. Direct immersion single-drop microextraction of an ionic association complex of rhodamine 6G with picric acid with subsequent fluorescent detection (λex was 532 nm and 525 nm for laser and LED, respectively; λem was 560 nm for both laser and LED) was used a model system to evaluate the new approach. The extractant phase was a 55 μL amyl acetate microdrop fixed in the optical part of the probe. LOD, LOQ and linear calibration range were found as 0.14, 0.48 and 0.5–10 nmol L−1, and 0.15, 0.50 and 0.5–5 nmol L−1 for laser and LED light sources, respectively. The accuracy of the method was assessed by analyzing real water samples.

Mass splittings and decay properties of B, Bs and Bc mesons in a Dirac formalism

In this paper, we investigate the mass spectra and decay properties of [Formula: see text], [Formula: see text] and [Formula: see text] mesons using the relativistic potential model with confining potential [Formula: see text]. The calculated mass spectra of [Formula: see text], [Formula: see text] and [Formula: see text] accord to the findings of the experiments and other theoretical forecasts. Using the same parameters, we calculate possible radiative decay widths of [Formula: see text] and [Formula: see text], [Formula: see text] and weak leptonic decay constants of [Formula: see text], [Formula: see text] and [Formula: see text] mesons. Our results, in most cases, generally agree with experimental and other theoretical predictions. Finally, we also investigate mixing parameters [Formula: see text], [Formula: see text] and [Formula: see text] for [Formula: see text] [Formula: see text] mesons, where our calculated values reasonably agree with the experiment.

Systematics of mean resonance spacing and average radiative width from random forest regression

The interaction of a nucleus with photons plays a key role in understanding a competition in nuclear reactions. The photon strength function (PSF) gives the average response of a nucleus to an electromagnetic probe. In this study, an estimation is performed of the mean resonance spacing and average radiative width of 22 nuclei in the range A = 46 – 90. The calculations for this analysis are done in TALYS. In addition, a machine-learning driven approach for determining experimentally obtained model parameters from the neutron/proton and mass number is given. A reasonable agreement within the uncertainties is achieved between the model dependent calculations, using TALYS, and results from random forest regression.

Spectroscopic behavior of fully heavy tetraquarks

Stimulated by the observation of the X(6900) from LHCb in 2020 and the recent results from CMS and ATLAS in the di-J/psi invariant mass spectrum, in this work we systematically study all possible configurations for the ground states of fully heavy tetraquark in the constituent quark model. By our calculation, we present their spectroscopic behaviors including binding energy, lowest meson–meson thresholds, specific wave function, magnetic moment, transition magnetic moment, radiative decay width, rearrangement strong width ratio, internal mass contributions, relative lengths between (anti)quarks, and the spatial distribution of four valence (anti)quarks. We cannot find a stable S-wave state for the fully heavy tetraquark system. We hope that our results will be valuable to further experimental exploration of fully heavy tetraquark states.

Radiative and semileptonic decay widths of heavy ground state baryons in diquark model

Radiative and semileptonic decay widths of heavy ground state baryons in diquark model

Improved S factor of the C12(p,γ)N13 reaction at E=320–620 keV and the 422 keV resonance

The 12C(p,{\gamma})13N reaction is the onset process of both the CNO and Hot CNO cycles that drive massive star, Red and Asymptotic Giant Branch star and novae nucleosynthesis. The 12C(p,{\gamma})13N rate affects the final abundances of the stable 12,13C nuclides, with ramifications for meteoritic carbon isotopic abundances and the s-process neutron source strength. Here, a new underground measurement of the 12C(p,{\gamma})13N cross-section is reported. The present data, obtained at the Felsenkeller shallow-underground laboratory in Dresden (Germany), encompass the 320-620 keV center of mass energy range to include the wide and poorly constrained E = 422 keV resonance that dominates the rate at high temperatures. This work S-factor results, lower than literature by 25%, are included in a new comprehensive R-matrix fit, and the energy of the 1+ first excited state of 13N is found to be 2369.6(4) keV, with radiative and proton width of 0.49(3) eV and 34.9(2) keV respectively. A new reaction rate, based on present R-matrix fit and extrapolation, is suggested.

A high-performance solar chimney in building integrated with photocatalytic technology for atmospheric methane removal

The techniques for the removal of methane from the atmosphere are highly challenging due to its stable chemical properties, dispersed sources, and low concentrations. This paper proposes a practical small-scale solar chimney (SC) in buildings with photocatalytic reactors (PCRs) for atmospheric methane removal. Two comprehensive numerical models on photocatalytic reaction and indoor ventilation are developed. The numerical simulation considers the performance of methane removal and indoor air ventilation of the proposed system, as well as its specific crucial parameters such as the type of PCRs, solar radiation, and flow channel width. The obtained results show that the SC with honeycomb photocatalytic reactor (HPCR) is more able to remove atmospheric methane than SC with plate photocatalytic reactor (PPCR) under the premise of meeting the ventilation standards. In addition, there is a maximum methane purification rate of 57.27 μg/s under the condition that the air gap width is 0.3 m, the length of the HPCR is 1.5 m, and the porosity is 0.85. It is then proved that the SC in buildings with PCRs can allow small-scale, zero-energy consumption, continuable, and decentralized low-concentration atmospheric methane removal while improving the indoor ventilation.

Radiative decays of the spin-2 partner of X(3872)

It has been generally expected that the X(3872) has a spin-2 partner, X2, with quantum numbers JPC=2++. In the hadronic molecular model, its mass was predicted to be below the D⁎D¯⁎ threshold, and the new structure reported in the γψ(2S) invariant mass distribution by the Belle Collaboration with mass M=(4014.3±4.0±1.5) MeV and decay width Γ=(4±11±6) MeV, with a global significance of 2.8 σ, is a nice candidate for it. We consider the radiative decay widths for the X2→γψ with ψ=J/ψ,ψ(2S) treating the X2 as a D⁎D¯⁎ shallow bound state, and estimate the events of X2 in two-photon collisions that can be collected in the γJ/ψ→γℓ+ℓ− (ℓ=e,μ) final states at Belle. Based on the upper limit for the ratio of decay widths of X(3872)→γψ(2S) and X(3872)→γJ/ψ measured by BESIII, we predict the similar ratio Γ(X2→γψ(2S))/Γ(X2→γJ/ψ) to be smaller than 1.0. We suggest searching for the X2 signal in the γJ/ψ invariant mass distribution via two-photon fusions. The results will lead to insights into both the X(3872) and the new structure observed by Belle.

Mass spectroscopy and decay properties of Ξcb, Ξbb baryons

Using the Hypercentral Constituent Quark Model (hCQM), the mass spectra of doubly heavy baryons [Formula: see text] and [Formula: see text] are determined. The model describes an interaction inside the baryonic system. Screened potential has been considered as confining potential with color-Coulomb potential to enumerate the masses of baryonic states. Regge trajectories have been plotted in [Formula: see text] plane. The properties like magnetic moment and radiative decay width have been determined using the obtained results.

Spectroscopic Study of $$\pmb {\varOmega _{cc}}$$, $$\pmb {\varOmega _{cb}}$$ and $$\pmb {\varOmega _{bb}}$$ Baryons

In this paper, we presented the mass spectra of the doubly heavy $\Omega$ baryons containing one light (strange) quark and two heavy (charm and bottom) quarks. Our predicted masses can be consider to determine the $J^p$ value for the resonances detected by experimental facilities in future. The masses of ground excited states (1S-6S, 1P-3P, 1D-2D, 1F-2F) are calculated for all possible $J^p$ values, using the Hypercentral Constituent Quark Model (hCQM), by employing screened potential as confining potential with color-Coloumb potential. Regge trajectories are also plotted in $(J, M^2)$ plane for natural and unnatural parities. Doubly heavy Omega states are not declared yet by any experimental facility. We compared our results to the predictions gained from other theoretical approaches, and we found that our predictions are quite close to those of them. Other properties such as magnetic moment (for spin state $\frac{1}{2}$ and $\frac{3}{2}$) and radiative decay width are calculated using the enuerated masses.