New behaviors of α-particle preformation factors near doubly magic 100Sn

The α-particle preformation factors of nuclei above doubly magic nuclei 100Sn and 208Pb are investigated.The results show that the α-particle preformation factors of nuclei near self-conjugatedoubly magic 100Sn are larger significantly than those of analogous nuclei just above 208Pb, andthey will be enhanced as the nuclei move towards the N = Z line. The correlation energy of theproton-neutron Ep-n and two protons-two neutrons E2p-2n of nuclei near 100Sn also exhibit similarsituations indicating that the interactions between protons and neutrons occupying similar single-particleorbitals could enhance the α-particle preformation factors and result in the superallowedα decay. It also provides evidence of the significant role of proton-neutron interaction on α-particlepreformation. Besides, the linear relationship between α-particle preformation factors and the productof valence protons and valence neutrons for nuclei around 208Pb is broken in the 100Sn regionbecause the α-particle preformation factor is enhanced when the nucleus near 100Sn moves towardsthe N = Z line. Furthermore, the calculated decay half-lives can well reproduce the experimentaldata including the recent observed self-conjugate nuclei 104Te and 108Xe [Phys. Rev. Lett. 121,182501 (2018)].

Quantifying the Effect of Initial Fluctuations on Isospin-Sensitive Observables from Heavy-Ion Collisions at Intermediate Energies

Initial fluctuation is one of the ingredients that washes fingerprints of the nuclear symmetry energy on observables in heavy-ion collisions. By artificially using the same initial nuclei in all collision events, the effect of the initial fluctuation on isospin-sensitive observables, e.g., the yield ratio of free neutrons with respect to protons Nn/Np, 3H/3He yield ratio, the yield ratio between charged pions π−/π+, and the elliptic flow ratio or difference between free neutrons and protons v2n/v2p (v2n-v2p), are studied within the ultrarelativistic quantum molecular dynamics (UrQMD) model. In practice, Au + Au collisions with impact parameter b = 5 fm and beam energy Elab = 400 MeV/nucleon are calculated. It is found that the effect of the initialization on the yields of free protons and neutrons is small, while for the yield of pions, the directed and elliptic flows are found to be apparently influenced by the choice of initialization because of the strong memory effects. Regarding the isospin-sensitive observables, the effect of the initialization on Nn/Np and 3H/3He is negligible, while π−/π+ and v2n/v2p (v2n-v2p) display a distinct difference among different initializations. The fingerprints of symmetry energy on π−/π+ and v2n/v2p can be either enhanced or reduced when different initializations are utilized.

Electrodisintegration of Deuteron into Dark Matter and Proton Close to Threshold

We discuss an investigation of the dark matter decay modes of the neutron, proposed by Fornal and Grinstein (2018–2020), Berezhiani (2017, 2018) and Ivanov et al. (2018) for solution of the neutron lifetime anomaly problem, through the analysis of the electrodisintegration of the deuteron d into dark matter fermions χ and protons p close to threshold. We calculate the triple-differential cross section for the reaction e−+d→χ+p+e− and propose to search for such a dark matter channel in coincidence experiments on the electrodisintegration of the deuteron e−+d→n+p+e− into neutrons n and protons close to threshold with outgoing electrons, protons, and neutrons in coincidence. An absence of neutron signals should testify to a detection of dark matter fermions.

Mass measurements of 99–101In challenge ab initio nuclear theory of the nuclide 100Sn

The tin isotope 100Sn is of singular interest for nuclear structure due to its closed-shell proton and neutron configurations. It is also the heaviest nucleus comprising protons and neutrons in equal numbers—a feature that enhances the contribution of the short-range proton–neutron pairing interaction and strongly influences its decay via the weak interaction. Decay studies in the region of 100Sn have attempted to prove its doubly magic character1 but few have studied it from an ab initio theoretical perspective2,3, and none of these has addressed the odd-proton neighbours, which are inherently more difficult to describe but crucial for a complete test of nuclear forces. Here we present direct mass measurements of the exotic odd-proton nuclide 100In, the beta-decay daughter of 100Sn, and of 99In, with one proton less than 100Sn. We use advanced mass spectrometry techniques to measure 99In, which is produced at a rate of only a few ions per second, and to resolve the ground and isomeric states in 101In. The experimental results are compared with ab initio many-body calculations. The 100-fold improvement in precision of the 100In mass value highlights a discrepancy in the atomic-mass values of 100Sn deduced from recent beta-decay results4,5.

Probing nuclear cluster symmetries through the harmonic oscillator

The present contribution explores the symmetries of the deformed harmonic oscillator for both prolate and oblate deformations. It demonstrates the emergence of clustering from the degeneracies of the deformed harmonic oscillator and the appearance of the cluster structures in the associated densities. The universality of molecular structures is presented, demonstrating that molecular-like exchange of protons and neutrons is encoded into the mean-field. The nature of oblate-like structures is also explored.

Nuclear Structure and Stability Arise from Alternating Quarks within Light Nuclei

<div><p>The atomic nucleus contains protons and neutrons, each made of 3 up or down quarks. No consensus exists on nuclear structure from among the 30+ models of the atomic nucleus. Here we present the Alternating Quark Model (AQM), which proposes a role for quarks in nuclear structure and stability. The uncertainty principle precludes <i>exact</i> localization of quarks; AQM structures are based on <i>average</i> quark positions. Quark sequences within light nuclei assume simple geometries, and resulting radius predictions demonstrate 99% (±1) agreement, and statistical correlation ρ = 0.99 (p<0.001), with accepted radii. Within the model, stable nuclides have nucleon structures (proton-<i>udu,</i> and neutron-<i>dud</i>) that link by quark-quark interactions to maintain an alternating quark sequence, with spacing between linked quarks equaling the radius of the proton (both within and between nucleons). The 18 quarks of Li-6 form a ring, and larger structures contain one or more complete or incomplete Li-6 rings stacked in parallel. Protons on one ring must align with neutrons on a parallel ring (and vice versa) to form closely correlated proton-neutron pairs. We show that structures violating an alternating quark sequence, or lacking proton-neutron pairing between rings, are unstable or don’t exist at all. The deuteron is an open-ended quark sequence whereas heavier nuclides contain quarks enclosed within one or more ring structures. This difference in local environment may account for the EMC effect. Electrostatic forces arising from alternating/unequal quark charges are shown to predict a Coulomb barrier between fusing nuclei. The Coulombic forces of fusing nuclei are then modeled with N/S alternating permanent magnets, yielding a magnetic potential barrier. Finally, we propose a structure for quarks as linked harmonic oscillators, and suggest a mechanism for beta decay.<br></p> </div>

Nuclear Structure and Stability Arise from Alternating Quarks within Light Nuclei

<div> <div> <p>The atomic nucleus is made of protons and neutrons, each comprising a mix of 3 up or down quarks. No consensus exists for nuclear structure from among the 30+ proposed models of the atomic nucleus, although they generally agree that quarks play no role. The light nuclides of interest to nuclear fusion exist in a purgatory of uncertainty, wanting not only for structure but also for some insight into their erratic sizes. The deuterium nucleus is twice the mass of the proton but 2.5 times larger. In fact, deuterium is larger than either tritium or helium-4. The lithium-7 nucleus is larger than all of these, yet smaller than lithium-6. Here we show that an alternating quark model (AQM) predicts these erratic nuclear radii to within 99% of experimental (SD 2.5%). The distance between sequential quarks is constant and equal to the radius of the proton. Quark structures assume simple geometries. Alternating quarks predict nuclear stability, the height of the Coulomb barrier, near-range attraction, and far-range repulsion. Through the lens of nonlinear dynamics, quarks behave as linked harmonic oscillators traveling within a basin of attraction. This satisfies the uncertainty principle while allowing localization of an average quark position. The alternating quark model thus represents an intersection between chaos theory and quantum mechanical uncertainty.<br></p> </div> </div>

Exergy: Mechanical Nuclear Physics Measures Pressure, Viscosity and X-Ray Resonance in K-Shell in a Classical Way

First, the liquid drop model assumes a priori; to the atomic nucleus composed of protons and neutrons, as an incompressible nuclear fluid that should comply with the Navier–Stokes 3D equations (N-S3D). Conjecture, not yet proven, however, this model has successfully predicted the binding energy of the nuclei. Second, the calculation of nuclear pressure p0∈1.42,1.94]1032Pa and average viscosity η=1.71×1024fm2/s, as a function of the nuclear decay constant k=p02η=1T1/2, not only complements the information from the National Nuclear Data Center, but also presents an analytical solution of (N- S3D). Third, the solution of (N-S3D) is a Fermi Dirac generalized probability function Pxyzt=11+ep02ηt−μx2+y2+z21/2, Fourth, the parameter μ has a correspondence with the Yukawa potential coefficient μ=αm=1/r, Fifth, using low energy X-rays we visualize and measure parameters of the nuclear surface (proton radio) giving rise to the femtoscope. Finally, we obtain that the pressure of the proton is 8.14 times greater than the pressure of the neutron, and 1000 times greater than the pressure of the atomic nucleus. Analyzed data were isotopes: 9≤Z≤92 and 9≤N≤200.

Atoms in Gaseous and Solid States and their Energy and Force Relationships under Transitional Behaviors

Recalling the conventional insights of different atomic states, it is possible to discover new insights, which can cope with the existing challenges. Atoms, in fact, form from the electrons and energy knot nets. Suitably intercrossed overt photons construct energy knots in atoms of all elements. In growing atoms of gaseous and solid states, schemes of intercrossing overt photons become different. To construct atomic lattice in any element, overt photons in suitable length and number intercross by keeping the centers of their lengths at a common point. A scheme of intercrossing overt photons frames energy knots simultaneously clamping to positioned electrons. Atoms are differentiated on the basis of their different numbers of energy knots and electrons. A number of unfilled states in an atom represents a valency. Excluding hydrogen, atoms possess the same valency as specified for them. However, two more electrons with two already prescribed ones for the first shell form the zeroth ring of atom. In the hydrogen atom, only two electrons are occupied by two energy knots; two overt photons of the least measured lengths intercross to form the shape like digit eight. In this way, four electrons remain occupied by four energy knots to form helium atom. Thus, a helium atom is related to a zeroth ring in all higher order atoms. In order to validate these aforementioned statements, the concept of studying protons and neutrons is no longer significant. As far as the atoms of gaseous state are concerned, electrons possess minimum required potential energy. In this way, electrons of gaseous atoms remain above the middle of occupied energy knots in more than half the length, and they keep on experiencing maximum required levitational force along the north pole. In atoms of solid state, electrons possess maximum required potential energy. In this way, electrons of solid atoms remain below the middle of occupied energy knots in more than half the length, and they keep on experiencing maximum required gravitational force along the south pole. Each transition state of the atom is under the established relation of energy and force. Under transitional energy of an atom, electrons deal with infinitesimal displacements within their occupied energy knots, where the orientational force keeps on engaging them to introduce the recovery, neutral, re-crystallization and liquid states. Electrons left to the center of atom orientate from north to east clockwise, and electrons right to the centre of atom orientate from north to west anti-clockwise during the conversion of gaseous atom to liquid state. On the other hand, electrons left to the center of atom orientate from south to east anti-clockwise, and electrons right to the center of atom orientate from south to west clockwise during the conversion of solid atom to liquid state. These fundamental revolutions shed new light on the development of sustainable science and engineering.