Sigma Meson Production in Nuclear Reactions

The sigma meson production in p ＋ ^12C and p A- ^40Ca reactions at the incident energy Ep = 1.5 GeV is investigated within the Quantum Molecular Dynamics model. The simulation results indicate a distinctive A dependence of the sigma production, that is, the increase of A is followed by an increase of the production cross sections. We find that the σ meson production in proton-induced reactions is strongly medium-dependent, and the produced σ mesons decaying in a denser medium experience a stronger mass shift towards lower masses. This mass shift is an experimentally accessible observable in the final state pion pairs, which do not suffer from reabsorption by the surrounding nucleons. It is pointed out that the ratio of measured sigma cross sections as a function of the sigma invariant-mass from various reactions is a good probe to explore the existence of the σ meson in a dense nuclear environment.

Bayesian model averaging(BMA)for nuclear data evaluation

To ensure agreement between theoretical calculations and experimental data,parameters to selected nuclear physics models are perturbed and fine-tuned in nuclear data evaluations.This approach assumes that the chosen set of models accurately represents the‘true’distribution of considered observables.Furthermore,the models are chosen globally,indicating their applicability across the entire energy range of interest.However,this approach overlooks uncertainties inherent in the models themselves.In this work,we propose that instead of selecting globally a winning model set and proceeding with it as if it was the‘true’model set,we,instead,take a weighted average over multiple models within a Bayesian model averaging(BMA)framework,each weighted by its posterior probability.The method involves executing a set of TALYS calculations by randomly varying multiple nuclear physics models and their parameters to yield a vector of calculated observables.Next,computed likelihood function values at each incident energy point were then combined with the prior distributions to obtain updated posterior distributions for selected cross sections and the elastic angular distributions.As the cross sections and elastic angular distributions were updated locally on a per-energy-point basis,the approach typically results in discontinuities or“kinks”in the cross section curves,and these were addressed using spline interpolation.The proposed BMA method was applied to the evaluation of proton-induced reactions on ^(58)Ni between 1 and 100 MeV.The results demonstrated a favorable comparison with experimental data as well as with the TENDL-2023 evaluation.

Explanation of Cold Nuclear Fusion and Biotransmutations

Low energy nuclear reactions are possible in condensed matter because of image forces. They result from induced charges at the surface of metals or very polarizable media. The height and width of the Coulomb barrier in free space can thus be reduced. Nuclear fusion requires also the formation of a compound nucleus in one of its excited states, but two deuterons yield an α particle that has 2 excited states. They are respectively accessible at high or low energies. Since the reduction of the Coulomb barrier depends on the local curvature of the interface, cold fusion becomes autocatalytic, but heat production is controllable. Even microbes, plants and animals can produce transmutations. They are also due to image forces. This solves a basic problem in nuclear physics and there are possible applications: facilitated synthesis of superheavy elements and development of a new type of energy sources. They are moderate, but safe.

Fusion hindrance in the neck evolution of symmetric nuclear reactions

Fusion hindrance in the radial degree of freedom for massive nuclear reactions is known for a long time. However the present work shows that the fusion hindrance also exists in the neck evolution. We calculate the potential at different distances and different neck parameters by the two-center liquid drop model and then check whether fusion hindrance exists in the neck evolution by examing the sign of slope of potential vs. the neck parameter. The area of fusion hindrance in the neck evolution is shown.

Nuclear Stopping and Pauli Blocking in Heavy-Ion Reactions near Fermi Energy

The dissipation phenomenon in the heavy-ion reaction at incident energy near the Fermi energy is studied by simulating the reaction ^129Xe＋^129Sn with the isospin-dependent quantum molecular dynamics model. The calculations involving a proper prescription of implementing the Pauli exclusion principle show that the isotropy ratio measured by free protons emitted in the reaction at energy slightly higher than the Fermi energy is in agreement with the experimental data recently released by the INDRA collaboration. A feasible value of the Pauli-blocking factor is estimated by comparing the theoretical results with the experimental data for the energy range considered here.

Inelastic Scattering of Dark Matter with Heavy Cosmic Rays

We investigate the impact of inelastic collisions between dark matter(DM)and heavy cosmic ray(CR)nuclei on CR propagation.We approximate the fragmentation cross-sections for DM-CR collisions using collider-measured proton-nuclei scattering cross-sections,allowing us to assess how these collisions affect the spectra of CR boron and carbon.We derive new CR spectra from DM-CR collisions by incorporating their cross-sections into the source terms and solving the diffusion equation for the complete network of reactions involved in generating secondary species.In a specific example with a coupling strength of b_(χ)=0.1 and a DM mass of m_(χ)=0.1 GeV,considering a simplified scenario where DM interacts exclusively with oxygen,a notable modification in the boron-to-carbon spectrum due to the DM-CR interaction is observed.Particularly,the peak within the spectrum,spanning from 0.1 to 10 GeV,experiences an enhancement of approximately 1.5 times.However,in a more realistic scenario where DM particles interact with all CRs,this peak can be amplified to twice its original value.Utilizing the latest data from AMS-02 and DAMPE on the boron-to-carbon ratio,we estimate a 95%upper limit for the effective inelastic cross-section of DM-proton as a function of DM mass.Our findings reveal that at m_(χ)?2 MeV,the effective inelastic cross-section between DM and protons must be less than O(10^(-32))cm^(2).

Strong screening effects on resonant nuclear reaction ^(23)Mg(p,γ) ^(24)Al in the surface of magnetars

Based on the theory of relativistic superstrong magnetic fields （SMFs）, by using the method of Thomas-Fermi-Dirac approximations, we investigate the problem of strong electron screening （SES） in SMFs and the influence of SES on the nuclear reaction of 23Mg （p, Y）24A1. Our calculations show that the nuclear reaction will be markedly effected by the SES in SMFs in the surface of magnetars. Our calculated screening rates can increase two orders of magnitude due to SES in SMFs.

（N-Z） Odd-Even Effect for the Non-Equilibrium Mechanism of （p, n） Reactions

The neutron spectra and angular distributions from （p,n） reactions in the input proton energy range 6-25 MeV were analyzed. These are the old experimental data, however, re-analysis of these data reveals very interesting peculiarities which never have been discussed before. The high energetic part of neutron spectrum due to the direct mechanism changes considerably from one isotope to other. This difference was described with incorporation of two components which provide the ＂broad bump＂, or ＂step like＂ shape of neutron spectra at high energy. The properties of these components are： different shape, energy shift between them, and very strong fluctuation between different isotopes for ratio of cross sections connected with partial contribution. One may conclude that shape of non-compound neutron spectrum demonstrates very strong （N-Z） odd-even effect. The direct comparison of experimental data, and semi-empirical results with （p,n） spectra predicted by the EMPIRE code, gave evidence that the traditional approach cannot predict this effect. New finding may explain the ＂constant temperature＂ dependence for level density in mass range A-60 discussed in several investigations. These new experimental peculiarities were demonstrated, and it may be considered as reality. At the same time there is not consequent physical model for their explanation. The fact that spectrum shape is correlated with N-Z value may give a hint that discussed effects are connected with ＂halo-neutrons＂.

Iterative Bayesian Monte Carlo for nuclear data evaluation

In this work,we explore the use of an iterative Bayesian Monte Carlo(iBMC)method for nuclear data evaluation within a TALYS Evaluated Nuclear Data Library(TENDL)framework.The goal is to probe the model and parameter space of the TALYS code system to find the optimal model and parameter sets that reproduces selected experimental data.The method involves the simultaneous variation of many nuclear reaction models as well as their parameters included in the TALYS code.The‘best’model set with its parameter set was obtained by comparing model calculations with selected experimental data.Three experimental data types were used:(1)reaction cross sections,(2)residual production cross sections,and(3)the elastic angular distributions.To improve our fit to experimental data,we update our‘best’parameter set—the file that maximizes the likelihood function—in an iterative fashion.Convergence was determined by monitoring the evolution of the maximum likelihood estimate(MLE)values and was considered reached when the relative change in the MLE for the last two iterations was within 5%.Once the final‘best’file is identified,we infer parameter uncertainties and covariance information to this file by varying model parameters around this file.In this way,we ensured that the parameter distributions are centered on our evaluation.The proposed method was applied to the evaluation of p+^(59)Co between 1 and 100 MeV.Finally,the adjusted files were compared with experimental data from the EXFOR database as well as with evaluations from the TENDL-2019,JENDL/He-2007 and JENDL-4.0/HE nuclear data libraries.

Nuclear Fusion Research and Development Need New Relativistic Mass and Energy Corrections Given by the Information Relativity Theory

Hundred years after the conjecture of the British astronomer Eddington that the sun is powered by nuclear fusion of hydrogen, new physics theory may help make energy harvesting by nuclear fusion soon a reality. Researchers as well as investors funding fusion megaprojects are asked to deal with new relativistic corrections for mass and energy proposed by Suleiman in his Information Relativity Theory (IRT). These corrections were calculated in this contribution. It will help to decide whether a venture will be successful and to save big investments when in doubt. The assumed optimal kinetic energy for controlled nuclear fusion must be corrected to a somewhat higher level. At very high kinetic energy in the upper GeV range, it remains not enough baryonic mass to be transformed in energy. The fusion probability faded out to zero already at the golden limit of the recession speed of between target nucleon and projectile nucleon. Cold nuclear fusion, if ever possible, is recommended for protons rather than deuterons at highest experimental possible temperatures around 1000 (K) and needs fine-tuned kinetic nucleon energy. It would be also of interest whether a golden ratio based nuclear fuel confinement chamber could be beneficial. In this connection, also cold nuclear fusion setups should be discussed. Nature is governed by the golden ratio and criticality of physical systems influenced by it, and nuclear physics is not an exception. Computer simulations of the underlying controlled nuclear fusion processes should gain profit from IRT corrected starting information and may tackle anew possible low energy nuclear transmutations considering the wave-like dark components of matter and energy.

Anomalous Nuclear Reaction in Earth’s Interior:a New Field in Physics Science?

Tritium （3^H） in excess of the atmospheric values was found at volcanic Lakes Pavin （France）, Laacher （Germany） and Nemrut （Turkey）, as well as Kilauea Volcano at Hawaii （USA） and other volcanoes. Because 3^H has a short half-life of 12.3 years, the tritium and the resulting 3^He must have formed recently in the Earth. The result suggests that nuclear reactions may generate a significant amount of tritium in the interior of the Earth, although we have not yet learned what the reaction mechanism may be responsible. The nuclear reaction that can be responsible for tritium production in the Earth is probably a new research field in physics science. Nuclear reactions that generate tritium might be a source of ＂missing＂ energy （heat） in the interior of the Earth. Finding in-situ 3^H in the mantle may exhibit an alternative explanation of 3^He origin in the deep Earth.

Measurement of anomalous nuclear reaction in deuterium-loaded metal

This paper reports on an experiment for testing natural nuclear fusion at low temperature searching for evidence of the origin of 3He from natural nuclear fusion in deep Earth. The experiment was carried out using deuterium-loaded titanium foil samples and powder sample. Detection of charged particle was carried out using a low-level charged particle spectrometer. An A1 foil was used as an energy absorber for identification of charged particle. Although the counting rate is very low in the experiment, the emission of energetic particle from the sample is observed and the particle is identified as a proton having energy about 2.8 MeV after exiting the titanium sample. This work provides a positive result for the emission of charged particle in the deuterium-loaded titanium foil samples at low temperature, but a negative result for the deuterium-loaded titanium powder sample. The average reaction yield is deduced to be （0.46±0.08） protons/h for the foil samples. With the suggestion that the proton originates from d-d reaction, we calculate the reaction rate for d-d reaction, and the obtained result is 1.4×10^-24 fusion/d-d.sec. The negative result of the deuterium-loaded titanium powder sample suggests that the reaction yield might be correlated with the density or microscopic variables of deuterium-loaded titanium materials. The negative result also indicates that d-d reaction catalysed by μ-meson from cosmic ray can be excluded in the samples in this experiment.

Dynamical Behavior of Core ^3He Nuclear Reaction-Diffusion Systems and Sun＇s Gravitational Field

The coupling of the sun's gravitational field with processes of diffusion and convection exerts a significant influence on the dynamical behavior of the core 3He nuclear reaction-diffusion system. Stability analyses of the system are made in this paper by using the theory of nonequilibrium dynamics. It is showed that, in the nuclear reaction regions extending from the center to about 0.38 times of the radius of the sun, the gravitational field enables the core 3He nuclear reaction-diffusion system to become unstable and, after the instability, new states to appear in the system have characteristic of time oscillation. This may change the production rates of both 7Be and 8B neutrinos.

Application of Nuclear Analysis in Assessment of Environmental Pollution Part 1 Contamination of Plant and Soilby Fluorine

Fluorine contaminates the environment. The study of fluorine contamination profile can be made easy by the use of nuclear analytic method. Measurement of prompt gamma emitted from bombarding fluorine polluted environmental sample with proton beam from accelerator provides rapid assessment of fluorine contamination. In this paper, 340 keV proton beam induced F 19 (P,αγ) O 16 reaction is performed, measurement of prompt gamma 6130 keV gives fluorine content in the soil and leaves of plants (parasol, cotton and glossy privet), taken from the fluorine polluted area.

Cold Nuclear Fusion in the Unitary Quantum Theory

The interaction of the charged particles in the new Unitary Quantum theory isconsidered. It is shown that the distance of approachment of deuterons to each other verystrongly depends on the phase of the wave function and not only upon the energy. This thesis isnot discussed in the conventional quantum theory. It can easily explain the experiments on thecold nuclear fusion.

Simulation and test of the SLEGS TOF spectrometer at SSRF

The Shanghai laser electron gamma source(SLEGS)is a powerful tool for exploring photonuclear physics,such as giant dipole resonance(GDR)and pygmy dipole resonance,which are the main mechanisms of collective nuclear motion.The goal of the SLEGS neutron time-of-flight(TOF)spectrometer is to measure GDR and specific nuclear structures in the energy region above the neutron threshold.The SLEGS TOF spectrometer was designed to hold 20 sets of EJ301 and LaBr3 detectors.Geant4 was used to simulate the efficiency of each detector and the entire spectrometer,which provides a reference for the selection of detectors and layout of the SLEGS TOF spectrometer.Under the events of 208Pb,implementations of coincidence and time-of-flight technology for complex experiments are available;thus,and neutron decay events can be separated.The performance of SLEGS TOF spectrometer was systematically evaluated using offline experiments,in which the time resolution reached approximately 0.9 ns.

Spatial and spectral measurement of laser-driven protons through radioactivation

The simultaneous measurement of the spatial profile and spectrum of laser-accelerated protons is important for further optimization of the beam qualities and applications.We report a detailed study regarding the underlying physics and regular procedure of such a measurement through the radioactivation of a stack composed of aluminum,copper,and CR-39 plates as well as radiochromic films(RCFs).After being radioactivated,the copper plates are placed on imaging plates(IPs)to detect the positrons emitted by the reaction products through contact imaging.The spectrum and energy-dependent spatial profile of the protons are then obtained from the IPs and confirmed by the measured ones from the RCFs and CR-39 plates.We also discuss the detection range,influence of electrons,radiation safety,and spatial resolution of this measurement.Finally,insights regarding the extension of the current method to online measurements and dynamic proton imaging are also provided.

Description of elastic scattering for 7Li-induced reactions on 1p-shell nuclei

The experimental data of elastic scattering angular distributions for 9Be,10B,11B,12C,13C,15N,and 16O targets from 4.5 to 131.8 MeV and 7Li target from 8.0 to 42.0 MeV are fitted to realize the global phenomenological optical potentials(GPOPs)for the 7Li-induced reactions on 1p-shell nuclei.Thus,the 7Li elastic scattering from the 1p-shell nuclei can be systematically described using the established GPOPs.The elastic scattering angular distributions are also reanalyzed using a microscopic method within the framework of the new version of double folding S?o Paulo potential(SPP2).To better describe the elastic scattering at backward angles,the contribution of elastic transfer is further estimated by the distorted wave Born approximation(DWBA)method.Based on the obtained GPOPs,the inelastic scattering angular distributions are also obtained through the coupled channels(CC)method for the different excited states.

Uncertainties of nuclear level density estimated using Bayesian neural networks

Nuclear level density(NLD)is a critical parameter for understanding nuclear reactions and the structure of atomic nuclei;however,accurate estimation of NLD is challenging owing to limitations inherent in both experimental measurements and theoretical models.This paper presents a sophisticated approach using Bayesian neural networks(BNNs)to analyze NLD across a wide range of models.It uniquely incorporates the assessment of model uncertainties.The application of BNNs demonstrates remarkable success in accurately predicting NLD values when compared to recent experimental data,confirming the effectiveness of our methodology.The reliability and predictive power of the BNN approach not only validates its current application but also encourages its integration into future analyses of nuclear reaction cross sections.

Quark nova model for fast radio bursts

Fast radio bursts （FRBs） are puzzling, millisecond, energetic radio transients with no discernible source; observations show no counterparts in other frequency bands. The birth of a quark star from a parent neutron star experiencing a quark nova - previously thought undetectable when born in isolation - provides a natural explanation for the emission characteristics of FRBs. The generation of unstable r-process elements in the quark nova ejecta provides millisecond exponential injection of electrons into the surrounding strong magnetic field at the parent neutron star＇s light cylinder via β-decay. This radio synchrotron emission has a total duration of hundreds of milliseconds and matches the observed spectrum while reducing the inferred dispersion measure by approximately 200 cm-3 pc. The model allows indirect measurement of neutron star magnetic fields and periods in addition to providing astronomical measurements of β-decay chains of unstable neutron rich nuclei. Using this model, we can calculate expected FRB average energies （- 1041 erg） and spectral shapes, and provide a theoretical framework for determining distances.