Decay Threshold Research Articles

Impact of reactor neutrino uncertainties on coherent scattering's discovery potential

Abstract Nuclear power reactors are the most intense man-made source of antineutrino's and have long been recognized as promising sources for coherent elastic neutrino-nucleus scattering (CE$\nu$NS) studies. Its observation and the spectral shape of the associated recoil spectrum is sensitive to a variety of exotic new physics scenarios and many experimental efforts are underway. Within the context of the reactor antineutrino anomaly, which initially indicated eV-scale sterile neutrino's, the modeling of the reactor antineutrino spectrum has seen a significant evolution in the last decade. Even so, uncertainties remain due to a variety of nuclear structure effects, incomplete information in nuclear databases and fission dynamics complexities. Here, we investigate the effects of these uncertainties on one's ability to accurately distinguish new physics signals. For the scenarios discussed here, we find that reactor spectral uncertainties are similar in magnitude to the projected sensitivities pointing towards a need for $\beta$ spectroscopy measurements below the inverse $\beta$ decay threshold.

How Does the Critical Torus Instability Height Vary with the Solar Cycle?

The ideal magnetohydrodynamic torus instability can drive the eruption of coronal mass ejections. The critical threshold of magnetic field strength decay for the onset of the torus instability occurs at different heights in different solar active regions, and understanding this variation could therefore improve space weather prediction. In this work, we aim to find out how the critical torus instability height evolves throughout the solar activity cycle. We study a significant subset of Helioseismic and Magnetic Imager (HMI) and Michelson Doppler Imager Space-Weather HMI Active Region Patches (SHARPs and SMARPs) from 1996 to 2023, totaling 21,584 magnetograms from 4436 unique active-region patches. For each magnetogram, we compute the critical height averaged across the main polarity inversion line, the total unsigned magnetic flux, and the separation between the positive and negative magnetic polarities. We find the critical height in active regions varies with the solar cycle, with higher (lower) average critical heights observed around solar maximum (minimum). We conclude that this is because the critical height is proportional to the separation between opposite magnetic polarities, which in turn is proportional to the total magnetic flux in a region, and more magnetic regions with larger fluxes and larger sizes are observed at solar maximum. This result is noteworthy because, despite the higher critical heights, more coronal mass ejections are observed around solar maximum than at solar minimum.

Mass, Spectroscopy, and Two-Neutron Decay of ^{16}Be.

The structure and decay of the most neutron-rich beryllium isotope, ^{16}Be, has been investigated following proton knockout from a high-energy ^{17}B beam. Two relatively narrow resonances were observed for the first time, with energies of 0.84(3) and 2.15(5)MeV above the two-neutron decay threshold and widths of 0.32(8) and 0.95(15)MeV, respectively. These were assigned to be the ground (J^{π}=0^{+}) and first excited (2^{+}) state, with E_{x}=1.31(6) MeV. The mass excess of ^{16}Be was thus deduced to be 56.93(13)MeV, some 0.5MeV more bound than the only previous measurement. Both states were observed to decay by direct two-neutron emission. Calculations incorporating the evolution of the wave function during the decay as a genuine three-body process reproduced the principal characteristics of the neutron-neutron energy spectra for both levels, indicating that the ground state exhibits a strong spatially compact dineutron component, while the 2^{+} level presents a far more diffuse neutron-neutron distribution.

Effect of wheat crops on the persistence and attenuation of antibiotic resistance genes in soil after swine wastewater application

Swine wastewater (SW) application introduces antibiotic resistance genes (ARGs) into farmland soils. However, ARG attenuation in SW-fertigated soils, especially those influenced by staple crops and soil type, remains unclear. This study investigated twelve soil ARGs and one mobile genetic element (MGE) in sandy loam, loam, and silt loam soils before and after SW application in wheat-planted and unplanted soils. The results revealed an immediate increase in the abundance of ARGs in soil by two orders of magnitude above background levels following SW application. After SW application, the soil total ARG abundance was attenuated, reaching background levels at 54 days; However, more individual ARGs were detected above the detection limit than pre-application. Among the 13 genes, acc(6′)-lb, tetM, and tetO tended to persist in the soil during wheat harvest. ARG half-lives were up to four times longer in wheat-planted soils than in bare soils. Wheat planting decreased the persistence of acc(6′)-lb, ermB, ermF, and intI2 but increased the persistence of others such as sul1 and sul2. Soil type had no significant impact on ARG and MGE fates. Our findings emphasize the need for strategic SW application and the consideration of crop cultivation effects to mitigate ARG accumulation in farmland soils.

Description of the Proton-Decaying 0_{2}^{+} Resonance of the α Particle.

The recent precise experimental determination of the monopole transition form factor from the ground state of ^{4}He to its 0_{2}^{+} resonance via electron scattering has reinvigorated discussions about the nature of this first excited state of the α particle. The 0_{2}^{+} state has been traditionally interpreted in the literature as the isoscalar monopole resonance (breathing mode) or, alternatively, as a particle-hole shell-model excitation. To better understand the nature of this state, which lies only ∼410 keV above the proton emission threshold, we employ the coupled-channel representation of the no-core Gamow shell model. By considering the [^{3}H+p], [^{3}He+n], and [^{2}H+^{2}H] reaction channels, we explain the excitation energy and monopole form factor of the 0_{2}^{+} state. We argue that the continuum coupling strongly impacts the nature of this state, which carries characteristics of the proton decay threshold.

The production of charm pentaquark from B meson within SU(3) analysis

We study the masses and production modes of pentaquark with the quark constituent cq¯qqq\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$c\\bar{q}qqq$$\\end{document}, by the tridiquark-diquark model and systematical light flavor quark symmetry SU(3) analysis. The mass spectrums show that the S-wave singly charm pentaquark cn¯nnn,cs¯ssn,cn¯ssn\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$c{\\bar{n}}nnn,~c{\\bar{s}}ssn,~c{\\bar{n}}ssn$$\\end{document} and cn¯snn\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$c{\\bar{n}}snn$$\\end{document}(n=u,d)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$(n=u,d)$$\\end{document} are above their strong decay thresholds, while cs¯nnn\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$c{\\bar{s}} nnn$$\\end{document} and cs¯snn\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$c\\bar{s} snn$$\\end{document} with parity 12-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\frac{1}{2}^-$$\\end{document} are below their strong decay thresholds, which imply the possibility of stable states. Furthermore, we discuss the production of the concerned 15 states from B meson, the analysis within SU(3) symmetry yields the golden channels of production process, B¯s0→Fs¯udd+p¯,B-→Fu¯dds-Λ¯0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\overline{B}}^0_s\\rightarrow F_{\\bar{s}udd}^{+} {\\overline{p}},\\ B^-\\rightarrow F_{\\bar{u}dds}^{-} {\\overline{\\Lambda }}^0$$\\end{document}, which expected to be work worthily in b-factory.

Caries clusters at lesion-severity thresholds: A Sierra Leone case study.

Despite being almost entirely preventable, globally, dental caries is extremely prevalent. Moreover, dental caries will continue to present an even larger challenge for lower income countries, particularly those in the African context, as they transition to a more Western diet. Hence, epidemiological data providing insight into disease patterns and trends is critical to inform public health action. The purpose of this study was to examine dental caries clusters by caries detection threshold among 15-year-old adolescents in Sierra Leone, using data from the latest national survey, and to explore associated sociodemographic factors. This paper presents a secondary analysis of oral health data on 490 15-year-olds from the Sierra Leone national oral health survey of schoolchildren. Hierarchical cluster analysis of dental caries experience was conducted across all surfaces at four decay detection thresholds using the International Caries Detection and Assessment System (ICDAS) (clinical: ICDAS 2-6, cavitated: ICDAS 3-6, obvious: ICDAS 4-6 and extensive obvious: ICDAS 5-6 decay) across the four regions of Sierra Leone. Ordered logistic regression was used to estimate the association of sociodemographic factors with generated clusters relating to clinical and obvious decay experience. These are of both clinical and epidemiological relevance. A 3-cluster decay pattern representing a 'low' to 'high' decay experience distribution was observed under each decay detection threshold across surfaces. For clinical decay (including visual enamel caries), 28.8% had low, 55.1% medium and 15.9% high caries status. In the adjusted model, the only significant risk factor across obvious and clinical decay thresholds was region, with adolescents outside the Western region more likely to experience decay. This study suggests that adolescents in Sierra Leone fall into three distinct caries clusters: low, medium to high decay experience distribution, regardless of decay threshold. It reinforces the importance of recognizing dental caries detection thresholds and the use of contemporary epidemiological methodology. This suggests that adolescents outside the Western region are likely to have higher caries experience. The data also provides insight to the nature of adolescents in each cluster and should help to inform policy and planning of the integration of oral health into primary care and school systems.

Interfering reaction channels observed in the 2H(8He,4He)6H reaction studies

In the recent work [Nikolskii et al., Phys. Rev. C 105, 064605 (2022)] the 2H(8He,4He)6H reaction was used for the study of the extreme neutron-rich 6H isotope. A broad bump was observed in the measured 6H spectrum interpreted as the broad overlapping ground and some low-lying states of this nuclide. There could be certain doubts in the interpretation of this work: in conditions of the limited phase space it is not impossible that the structure in the missing mass spectrum of 6H is actually induced by the resonant states populated by some other channels opened in the 8He+2H interaction. This work provides a body of the evidence for the correct channel identification and for the absence of the 6H resonances at energy ET = 0 − 3.5 MeV above the 3H+3n decay threshold. In addition the first strong experimental evidence is given that the 6H → 5H*+n → 3H+3n sequential decay is the dominating 6H decay channel.

Remaining useful life prediction of the lithium-ion battery based on CNN-LSTM fusion model and grey relational analysis

<abstract> <p>The performance of lithium-ion batteries will decline dramatically with the increase in usage time, which will cause anxiety in using lithium-ion batteries. Some data-driven models have been employed to predict the remaining useful life (RUL) model of lithium-ion batteries. However, there are limitations to the accuracy and applicability of traditional machine learning models or just a single deep learning model. This paper presents a fusion model based on convolutional neural network (CNN) and long short-term memory network (LSTM), named CNN-LSTM, to measure the RUL of lithium-ion batteries. Firstly, this model uses the grey relational analysis to extract the main features affecting the RUL as the health index (HI) of the battery. In addition, the fusion model can capture the non-linear characteristics and time-space relationships well, which helps find the capacity decay and failure threshold of lithium-ion batteries. The experimental results show that: 1) Traditional machine learning is less effective than LSTM. 2) The CNN-LSTM fusion model is superior to the single LSTM model in predicting performance. 3) The proposed model is superior to other comparable models in error indexes, which could reach 0.36% and 0.38e-4 in mean absolute percentage error (MAPE) and mean square error (MSE), respectively. 4) The proposed model can accurately find the failure threshold and the decay fluctuation for the lithium-ion battery.</p> </abstract>

Event-triggered distributed optimization of multi-agent systems with time delay.

In this article, the distributed optimization based on multi-agent systems was studied, where the global optimization objective of the optimization problem is a convex combination of local objective functions. In order to avoid continuous communication among neighboring agents, an event-triggering algorithm was proposed. Time delay was also considered in the designed algorithm. The triggering time of each agent was determined by the state measurement error, the state of its neighbors at the latest triggering instant and the exponential decay threshold. Some sufficient conditions for optimal consistency were obtained. In addition, Zeno-behavior in triggering time sequence was eliminated. Finally, a numerical simulation was given to prove the effectiveness of the proposed algorithm.

Unbound states in 17C and p-sd shell-model interactions

Unbound states in C17 were investigated via one-neutron removal from a C18 beam at an energy of 245 MeV/nucleon on a carbon target. The energy spectrum of C17, above the single-neutron decay threshold, was reconstructed using invariant mass spectroscopy from the measured momenta of the C16 fragment and neutron, and was found to exhibit resonances at Er=0.52(2), 0.77(2), 1.36(1), 1.91(1), 2.22(3) and 3.20(1) MeV. The resonance at Er=0.77(2) MeV [Ex=1.51(3) MeV] was provisionally assigned as the second 5/2+ state. The two resonances at Er=1.91(1) and 3.20(1) MeV [Ex=2.65(2) and 3.94(2) MeV] were identified, through comparison of the energies, cross sections and momentum distributions with shell-model and eikonal reaction calculations, as p-shell hole states with spin-parities 1/21− and 3/21−, respectively. A detailed comparison was made with the results obtained using a range of shell-model interactions. The YSOX shell-model Hamiltonian, the cross-shell part of which is based on the monopole-based universal interaction, was found to provide a very good description of the present results and those for the neighbouring odd-A carbon isotopes – in particular for the negative parity cross-shell states.

Fully Heavy Tetraquark Spectroscopy in the Relativistic Quark Model

Masses of the ground and excited (1P, 2S, 1D, 2P, 3S) states of the fully heavy tetraquarks, composed of charm (c) and bottom (b) quarks and antiquarks, are calculated in the diquark–antidiquark picture within the relativistic quark model based on the quasipotential approach and quantum chromodynamics. The quasipotentials of the quark–quark and diquark–antidiquark interactions are constructed similarly to the previous consideration of mesons and baryons. Relativistic effects are consistently taken into account. A tetraquark is considered a bound state of a diquark and an antidiquark. The finite size of the diquark is taken into account, using the form factors of the diquark–gluon interaction. It is shown that most of the investigated states of tetraquarks lie above the decay thresholds into a meson pair; as a result, they can be observed only as broad resonances. The narrow state X(6900) recently discovered in the di-J/ψ production spectrum by the LHCb, CMS and ATLAS Collaborations corresponds to an excited state of the fully charmed tetraquark. Other recently discovered exotic heavy resonances, X(6200), X(6400), X(6600), X(7200), and X(7300), can also be interpreted as the different excitations of the fully charmed tetraquark.

Cascading parametric decay coupling between whistler and ion acoustic waves: Darwin particle-in-cell simulations

We present the results of numerical studies of the whistler wave parametric decay instability in the system with the suppressed Landau damping of ion acoustic waves (IAWs) based on the self-consistent Darwin particle-in-cell (PIC) model. It has been demonstrated that a monochromatic whistler wave launched along the background magnetic field couples to a counter-propagating whistler mode and co-propagating ion acoustic mode. The coupling of the electromagnetic mode to the electrostatic mode is guided by a ponderomotive force that forms spatio-temporal beat patterns in the longitudinal electric field generated by the counter-propagating whistler and the pump whistler wave. The threshold amplitude for the instability is determined to be δBw/B0 = 0.028 and agrees with a prediction for the ion decay instability: δBw/B0 = 0.042 based on the linear kinetic damping rates, and δBw/B0 = 0.030 based on the simulation derived damping rates. Increasing the amplitude of the pump whistler wave, the secondary and tertiary decay thresholds are reached, and cascading parametric decay from the daughter whistler modes is observed. At the largest amplitude (δBw/B0 ∼ 0.1) the primary IAW evolves into a short-lived and highly nonlinear structure. The observed dependence of the IAW growth rate on the pump wave amplitude agrees with the expected trend; however, quantitatively, the growth rate of the IAW is larger than expected from theoretical predictions. We discuss the relevant space regimes where the instability could be observed and extensions to the parametric coupling of whistler waves with the electron acoustic wave (EAW).

β −p and β−α decay of the 11Be neutron halo ground state

Beta-delayed proton emission from the neutron halo ground state of 11Be raised much attention due to the unusually high decay rate. It was argued that this may be due to the existence of a resonance just above the proton decay threshold. In this letter, we use the lenses of real-energy continuum shell model to describe several observables including the Gamow–Teller rates for the β −-delayed α and proton decays, and argue that, within our model, the large β −p branching ratio cannot be reconciled with other data.

Pengaruh Penyimpanan Beku Minced Fish Dan Frekuensi Pencucian Terhadap Kualitas Mutu Surimi Dan Kamaboko Ikan Patin (Pangasius sp.)

The study aimed to analyze the effect of frozen minced fish storage and washing cycle to the quality of surimi and kamaboko catfish (Pangasius sp). The experimental design used was randomized compact design with treatment of storage time (0,14,28) day and washing cycle treatment (1,2,3, and 4). The results showed that the storage time and washing frequency significantly affect the expressible water, while not significant effect on white duct, folding test and teeth cutting test. The highest values of surimi and kamaboko catfish from each treatment are whiteness test at surimi of 49,27% and 63.55% at kamaboko, folding test with value 7, teeth cutting test 7 and expressible water have the highest value of 35 at kamaboko and has a TVBN value which is still below the decay threshold, which is in the range of 11.295-12.085 mg N/100 g.

Effect of plasma-activated water on microbial quality and physicochemical properties of fresh beef

Abstract This work studies the influence of plasma-activated water (PAW) on the decontamination of beef and its influence on the color, pH, the thiobarbituric acid reactive substance values (TBARS), and total volatile basic nitrogen (TVBN) values of meat. PAW was generated using non-thermal atmospheric pressure plasma jet (NTAPPJ). He + 0.2% N2 and He + 0.2% O2 were used as worker gas to generate PAW. The PAW produced by the He + O2 plasma system exhibited a higher potential for decontamination of beef than that produced by the He + N2 plasma system. The lightness value (L*) of treated beef does not exhibit a noticeable difference with the control one. TBARS values of all treated beef were lower than the rancidity threshold but significantly greater than that of control samples. The TVBN value of control beef samples reached the decay threshold after 18 days of stockpiling, but treated beef remained good. This work reveals that PAW can potentially inhibit the growth of microorganisms in beef.

H6 states studied in the H2(He8,He4) reaction and evidence of an extremely correlated character of the H5 ground state

The extremely neutron-rich system $^{6}$H was studied in the direct $^2\text{H}(^8\text{He},{^4\text{He}})^{6}$H transfer reaction with a $26 A$ MeV secondary $^{8}$He beam. The measured missing mass spectrum shows a broad bump at $\sim 4-8$ MeV above the $^3$H+$3n$ decay threshold. This bump can be interpreted as a broad resonant state in $^{6}$H at $6.8(5)$ MeV. The population cross section of such a presumably $p$-wave state (or may be few overlapping states) in the energy range from 4 to 8 MeV is $d\sigma/d\Omega_{\text{c.m.}} \simeq 190^{+40}_{-80}$ $\mu$b/sr in the angular range $5^{\circ}<\theta_{\text{c.m.}}<16^{\circ}$. The obtained missing mass spectrum is practically free of the $^{6}$H events below 3.5 MeV ($d\sigma/d\Omega_{\text{c.m.}} \lesssim 5$ $\mu$b/sr in the same angular range). The steep rise of the $^{6}$H missing mass spectrum at $\sim 3$ MeV allows to derive the lower limit for the possible resonant-state energy in $^{6}$H to be $4.5(3)$ MeV. According to the paring energy estimates, such a $4.5(3)$ MeV resonance is a realistic candidate for the $^{6}$H ground state (g.s.). The obtained results confirm that the decay mechanism of the $^{7}$H g.s.\ (located at 2.2 MeV above the $^{3}$H+$4n$ threshold) is the "true" (or simultaneous) $4n$ emission. The resonance energy profiles and the momentum distributions of fragments of the sequential $^{6}$H$ \,\rightarrow \, ^5$H(g.s.)+$n\, \rightarrow \, ^3$H+$3n$ decay were analyzed by the theoretically-updated direct four-body-decay and sequential-emission mechanisms. The measured momentum distributions of the $^{3}$H fragments in the $^{6}$H rest frame indicate very strong "dineutron-type" correlations in the $^{5}$H ground state decay.

Parameter dependence and analysis of the 2HDM neutral Higgs boson pair production and decay at future lepton colliders

In this work, we present a study of the neutral Higgs bosons in the two Higgs doublet model (2HDM) in terms of their production processes and decay channels as a function of the model parameters. The analysis is performed for all four types of the 2HDM and the most promising processes and decay channels are identified for each type of the model. Several Higgs boson mass scenarios below and above the threshold of decay to gauge boson pair are introduced and the corresponding categories of final states are analyzed. The event analysis including collider beam spectrum and detector simulation shows that future lepton colliders have the potential to explore regions in the 2HDM parameter space, which have not yet been excluded by LHC, in a few weeks of operation. Final results are presented in terms of the signal distributions on top of the background and 95% CL exclusion and 5σ contours based on center of mass energy of s=500 GeV at the Compact Linear Collider (CLIC) or International Linear Collider (ILC).

New narrow resonances observed in the unbound nucleus F15

The structure of the unbound F15 nucleus is investigated using the inverse kinematics resonant scattering of a radioactive O14 beam impinging on a CH2 target. The analysis of H1(O14,p)O14 and H1(O14,2p)N13 reactions allowed the confirmation of the previously observed narrow 1/2− resonance, near the two-proton decay threshold, and the identification of two new narrow 5/2− and 3/2− resonances. The newly observed levels decay by 1p emission to the ground of O14, and by sequential 2p emission to the ground state of N13 via the 1− resonance of O14. Gamow shell model (GSM) analysis of the experimental data suggests that the wave functions of the 5/2− and 3/2− resonances may be collectivized by the continuum coupling to nearby 2p- and 1p-decay channels. The observed excitation function H1(O14,p)O14 and resonance spectrum in F15 are well reproduced in the unified framework of the GSM.Received 1 December 2021Accepted 7 April 2022DOI:https://doi.org/10.1103/PhysRevC.105.L051301©2022 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasNuclear reactionsNuclear structure & decaysResonance reactionsProperties6 ≤ A ≤ 19Nuclear Physics

Event-Driven Multiagent Consensus Disturbance Rejection With Input Uncertainties via Adaptive Protocols

This article focuses on the multiagent consensus disturbance rejection (MCDR) for groups of general linear individuals by using the distributed event-based adaptive control technique. Based on designing disturbance observers, event-driven control rules involving controllers and actuator updating rules are provided for networks of multiple individuals without and with input uncertainties; the updating rules rely on the state-dependent factor, the exponential decay threshold, and a tuning parameter. For both scenarios, the global information of network topologies is not required in the design and continuous communications between agents can be avoided.