Showing papers in "International Journal of Modern Physics E-nuclear Physics in 2015"
TL;DR: In this paper, a review of results from lattice QCD calculations on the thermodynamics of strong-interaction matter with emphasis on input these calculations can provide to the exploration of the phase diagram and properties of hot and dense matter created in heavy ion experiments is presented.
Abstract: We review results from lattice QCD calculations on the thermodynamics of strong-interaction matter with emphasis on input these calculations can provide to the exploration of the phase diagram and properties of hot and dense matter created in heavy ion experiments. This review is organized in sections as follows: (1) Introduction, (2) QCD thermodynamics on the lattice, (3) QCD phase diagram at high temperature, (4) Bulk thermodynamics, (5) Fluctuations of conserved charges, (6) Transport properties, (7) Open heavy flavors and heavy quarkonia, (8) QCD in external magnetic fields, (9) Summary.
303 citations
TL;DR: In this article, a brief review of the theory of viscous hydrodynamics is provided, including derivation of the 2nd order viscous hydride from the linear response theory and kinetic theory, viscous anisotropic hyddynamics, and numerical implementation of relativistic hyddride.
Abstract: Hydrodynamics has been successful in providing a good description of the bulk dynamics in ultra-relativistic heavy ion collisions. In this brief review, we provide basics of the theory of viscous hydrodynamics. Topics covered include derivation of the 2nd order viscous hydrodynamics from the linear response theory and kinetic theory, viscous anisotropic hydrodynamics, and numerical implementation of relativistic hydrodynamics.
162 citations
TL;DR: In this paper, a review of recent theoretical developments in the study of the structure of jets that are produced in ultra relativistic heavy ion collisions is presented, focusing on the dynamics of the parton cascade that is induced by the interactions of a fast parton crossing a quark-gluon plasma.
Abstract: We review recent theoretical developments in the study of the structure of jets that are produced in ultra relativistic heavy ion collisions. The core of the review focusses on the dynamics of the parton cascade that is induced by the interactions of a fast parton crossing a quark–gluon plasma. We recall the basic mechanisms responsible for medium induced radiation, underline the rapid disappearance of coherence effects, and the ensuing probabilistic nature of the medium induced cascade. We discuss how large radiative corrections modify the classical picture of the gluon cascade, and how these can be absorbed in a renormalization of the jet quenching parameter q. Then, we analyze the (wave)-turbulent transport of energy along the medium induced cascade, and point out the main characteristics of the angular structure of such a cascade. Finally, color decoherence of the in-cone jet structure is discussed. Modest contact with phenomenology is presented towards the end of the review.
142 citations
TL;DR: A brief introduction to the concept and framework for the study of jet quenching is provided in this article, where different approaches and implementation of multiple scattering and parton energy loss are discussed.
Abstract: Jet quenching in high-energy heavy-ion collisions can be used to probe properties of hot and dense quark–gluon plasma. We provide a brief introduction to the concept and framework for the study of jet quenching. Different approaches and implementation of multiple scattering and parton energy loss are discussed. Recent progresses in the theoretical and phenomenological studies of jet quenching in heavy-ion collisions at RHIC and LHC are reviewed.
140 citations
TL;DR: In this article, the authors summarize salient features of these evolution equations and the methods employed so far to derive them and emphasize applications to situations of observational interest, emphasizing applications for situations of interest.
Abstract: Neutrinos propagate in astrophysical and cosmological environments modifying their flavor in intriguing ways. The study of neutrino propagation in media is based on the mean-field, extended mean-field and Boltzmann equations. We summarize salient features of these evolution equations and the methods employed so far to derive them. We emphasize applications to situations of observational interest.
67 citations
TL;DR: In this article, the theory behind the GW-driven r-mode instability in rapidly rotating neutron stars (NSs) was reviewed, and some additional physical mechanisms that could reconcile theory with observations were discussed.
Abstract: In this paper, I will review the theory behind the gravitational wave (GW) driven r-mode instability in rapidly rotating neutron stars (NSs) and discuss which constraints can be derived from observations of spins and temperatures in low mass X-ray binaries (LMXBs). I will discuss how a standard, 'minimal' NS model is not consistent with the data, and discuss some of the additional physical mechanisms that could reconcile theory with observations. In particular, I will focus on additional forms of damping due to exotic cores and on strong mutual friction due to superfluid vortices cutting through superconducting flux tubes, and examine the repercussions these effects could have on the saturation amplitude of the mode. Finally I will also discuss the possibility that oscillations due to r-modes may have been recently observed in the X-ray light curves of two LMXBs.
66 citations
TL;DR: In this paper, a review aims to highlight several applications to heavy ion collisions including far-from-equilibrium dynamics, hydrodynamics and jet energy loss at strong coupling.
Abstract: Gauge/gravity duality has provided unprecedented opportunities to study dynamics in certain strongly coupled gauge theories. This review aims to highlight several applications to heavy ion collisions including far-from-equilibrium dynamics, hydrodynamics and jet energy loss at strong coupling.
54 citations
TL;DR: In this paper, it was shown that de-confinement can be achieved in high multiplicity nonjet pp collisions at s = 1.8TeV Fermi National Accelerator Laboratory (FNAL- E735) experiment.
Abstract: It is shown that de-confinement can be achieved in high multiplicity nonjet pp collisions at s = 1.8TeV Fermi National Accelerator Laboratory (FNAL- E735) experiment. Previously, the evidence for de-confinement was demonstrated by the constant freeze out energy density in high multiplicity events. In this paper, we use the same but analyze the transverse momentum spectrum in the framework of the clustering of color sources. This frame work naturally predicts the reduction in the charged particle multiplicity with respect to the value expected from the number of independent strings. The charged particle pseudorapidity densities in the range 7.0 ≤〈dNc/dη〉≤ 26.0 are considered. Results are presented for both thermodynamic and transport properties. The initial temperature and energy density are obtained from the data via the color reduction factor F(ξ) and the associated string density parameter ξ. The Bjorken ideal fluid description of the QGP, when modified by the color reduction factor and the trace anomaly Δ is in remarkable agreement with the lattice quantum chromo dynamics (LQCD) simulations. The energy density (e/T4) ∼ 11.5 for 〈dNc/dη〉∼ 25.0 is close to the value for 0–10% central events in Au+Au collisions at sNN = 200GeV. The shear viscosity to entropy density ratio (η/s) is ∼0.2 at the transition temperature of 167MeV. The result for the trace anomaly Δ is in excellent agreement with LQCD simulations. These results confirm our earlier observation that the de-confined state of matter was created in high multiplicity events in pp collisions at s = 1.8TeV.
48 citations
TL;DR: In this article, the Skyrme energy density for the parameter set SLy4 was used to fit the resulting radii and diffuseness data, which is useful to estimate the values of the unmeasured radii, especially in extrapolating charge radii values for nuclei which are far from the valley of stability.
Abstract: Proton and neutron density profiles of 760 nuclei in the mass region of A = 16−304 are analyzed using the Skyrme energy density for the parameter set SLy4. Simple formulae are obtained to fit the resulting radii and diffuseness data. These formulae are useful to estimate the values of the unmeasured radii and especially in extrapolating charge radii values for nuclei which are far from the valley of stability. Also, it provides an easy way to formulate the density profile for nuclear applications and to perform analytic calculations for bound and/or scattering problems. The obtained neutron and proton root-mean-square (rms) radii and the neutron skin thicknesses are in agreement with the available experimental data and previous Hartree–Fock (HF) calculations.
41 citations
TL;DR: In this article, a new set of global phenomenological optical model potential (OMP) parameters for alpha projectile is obtained by simultaneously fitting the experimental data of reaction cross-sections and elastic scattering angular distributions in the mass range of target nuclei 20 ≤A ≤ 209 at incident energies below 386MeV.
Abstract: A new set of global phenomenological optical model potential (OMP) parameters for alpha projectile is obtained by simultaneously fitting the experimental data of reaction cross-sections and elastic scattering angular distributions in the mass range of target nuclei 20 ≤A ≤ 209 at incident energies below 386MeV. The total reaction cross-sections and elastic scattering angular distributions are calculated and compared with experimental data for different targets. A satisfactory agreement is presented between them.
37 citations
TL;DR: In this paper, a perturbative-kinetic approach to jet propagation, energy loss, and momentum broadening in a high temperature quark-gluon plasma is presented.
Abstract: We present an overview of a perturbative-kinetic approach to jet propagation, energy loss, and momentum broadening in a high temperature quark–gluon plasma. The leading-order kinetic equations describe the interactions between energetic jet-particles and a non-abelian plasma, consisting of on-shell thermal excitations and soft gluonic fields. These interactions include ↔ scatterings, collinear bremsstrahlung, and drag and momentum diffusion. We show how the contribution from the soft gluonic fields can be factorized into a set of Wilson line correlators on the light-cone. We review recent field-theoretical developments, rooted in the causal properties of these correlators, which simplify the calculation of the appropriate Wilson lines in thermal field theory. With these simplifications lattice measurements of transverse momentum broadening have become possible, and the kinetic equations describing parton transport have been extended to next-to-leading order in the coupling g.
TL;DR: In this paper, the authors considered the hyperon puzzle of neutron star (NS) and employed Skyrme force models for the description of in-medium nucleon-nucleon (NN), nucleon−Lambda hyperon (NΛ) and Lambda-lambda (λ) interactions.
Abstract: We consider the so-called hyperon puzzle of neutron star (NS). We employ Skyrme force models for the description of in-medium nucleon–nucleon (NN), nucleon–Lambda hyperon (NΛ) and Lambda–Lambda (ΛΛ) interactions. A phenomenological finite-range force (FRF) for the ΛΛ interaction is considered as well. Equation of state (EoS) of NS matter is obtained in the framework of density functional theory, and Tolman–Oppenheimer–Volkoff (TOV) equations are solved to obtain the mass-radius relations of NSs. It has been generally known that the existence of hyperons in the NS matter is not well supported by the recent discovery of large-mass NSs (M ≃ 2M⊙) since hyperons make the EoS softer than the one without them. For the selected interaction models, NΛ interactions reduce the maximum mass of NS by about 30%, while ΛΛ interactions can give about 10% enhancement. Consequently, we find that some Skyrme force models predict the maximum mass of NS consistent with the observation of 2M⊙ NSs, and at the same time satisfy observationally constrained mass-radius relations.
DSM1
TL;DR: In this article, the early stages of heavy ion collisions at high energy in the Color Glass Condensate framework are described, from the pre-collision high energy nuclear wave function to the point where hydrodynamics may start becoming applicable.
Abstract: In this review, I present the description of the early stages of heavy ion collisions at high energy in the Color Glass Condensate framework, from the pre-collision high energy nuclear wave function to the point where hydrodynamics may start becoming applicable.
TL;DR: In this paper, the Dirac equation is solved with the combination of Generalized Poschl-Teller and Hyperbolical potentials within the framework of supersymmetric approach, and the energy levels are obtained for both pseudospin and spin symmetries.
Abstract: By using the new approximation type, the Dirac equation is solved with the combination of Generalized Poschl–Teller and Hyperbolical potentials within the framework of supersymmetric approach. The energy levels are obtained for both pseudospin and spin symmetries and the nonrelativistic limit is obtained with the corresponding wave functions in terms of hypergeometric functions. Some thermodynamic properties are equally obtained with the energy equation of the nonrelativistic limit.
TL;DR: Based on the Perey-Buck nonlocal optical model potential (NLOMP) as discussed by the authors, a new set of parameters for proton and neutron scattering off nuclei were obtained.
Abstract: Based on the Perey–Buck nonlocal optical model potential, F. Perey and B. Buck, Nucl. Phys. 32 (1962) 353, we obtain a new set of nonlocal optical model potential (NLOMP) parameters for proton and neutron scattering off nuclei. The experimental angular distributions of nucleon scattering off nuclei ranging from 27Al to 208Pb with incident energies around 10 MeV to 30 MeV are adopted in the fitting procedures. This NLOMP is energy independent. The chi-squares χ2 obtained in the fittings are comparable to those from the KD03 phenomenological local optical model potentials (OMP) A. Koning and J. Delaroche, Nucl. Phys. A 713 (2003) 231. Good agreement is found in comparisons between optical model calculations using this NLOMP and KD03 in their reproduction to the experimental angular distributions of elastic scattering cross-sections and analyzing powers.
TL;DR: In this paper, the difference between hadron resonance gas (HRG) calculations for chemical freeze-out parameters at fully and partly chemical equilibria was investigated, and the results were compared with the particle ratios measured in central Au-Au collisions at a wide range of nucleon-nucleon center-of-mass energies, as offered by the STAR experiment.
Abstract: In this paper, we investigate the difference between hadron resonance gas (HRG) calculations for chemical freeze-out parameters at fully and partly chemical equilibria. To this end, the results are compared with the particle ratios measured in central Au–Au collisions at a wide range of nucleon–nucleon center-of-mass energies, as offered by the STAR experiment. We restrict the discussion to STAR, because of large statistics and overall homogeneity of STAR measurements (one detector) against previous experiments. We find that the matter produced at these energies is likely in fully chemical equilibria, which is consistent with recent lattice quantum chromodynamics (QCD) results. The possible improvements by partial chemical equilibria (γS ≠ 1) are very limited. We also discuss these results with the ones deduced from ϕ/π- and Ω-/π- ratios. These hadron ratios are sensitive to the degree of chemical equilibrium. Accordingly, the conclusion that the matter produced reaches fully chemical equilibria in central Au–Au at relativistic heavy-ion collider (RHIC) energies is confirmed.
TL;DR: In this paper, the authors compared the kinetics of particle formation and decay in ultra-dense deuterium D(0) with a shadowed loop collector behind a 1.5 mm-thick steel plate.
Abstract: The ejection of particles with energy up to 20 MeV u-1 was reported previously from laser-induced processes in ultra-dense deuterium D(0). Studies of the kinetics of particle formation and decay, and of particle penetration through thick plates are now reported. Magnetic deflection is used to remove charged particles like electrons formed at the target. The signals at a collector in the beam at 0.9 m distance and a shadowed loop collector behind a 1.5–4.5 mm thick steel plate at 0.6 m are compared. The signal at the distant collector matches an intermediate particle B in a decay chain A → B → C with formation and decay time constants of 5–15 ns. The signal at the loop collector is delayed relative to the more distant collector, thus showing a delay of the particles penetrating through the steel plate. The signal at this collector is due to pair production with charge cancellation. Compton electrons from gamma radiation are observed at peak current densities of 1 mA cm-2 at the distant collector.
TL;DR: In this article, closed analytical expressions for eigenvalues and eigenfunctions of the Bohr Hamiltonian with the Manning-Rosen potential for γ−unstable nuclei as well as exactly separable rotational ones with γ ≈ 0.
Abstract: In the present paper, we have obtained closed analytical expressions for eigenvalues and eigenfunctions of the Bohr Hamiltonian with the Manning–Rosen potential for γ−unstable nuclei as well as exactly separable rotational ones with γ ≈ 0. Some heavy nuclei with known β and γ bandheads have been fitted by using two parameters in the γ−unstable case and three parameters in the axially symmetric prolate deformed one. A good agreement with experimental data has been achieved.
TL;DR: The multi-MeV particles ejected from pulsed laser-induced processes in ultra-dense hydrogen H(0) are observed in vacuum at three different distances up to 2m from the laser target.
Abstract: The multi-MeV particles ejected from pulsed laser-induced processes in ultra-dense hydrogen H(0) are observed in vacuum at three different distances up to 2m from the laser target. In previous publications, massive neutral particles with energy of 1–30MeVu−1 were identified. Direct energy spectra of the particles show energies well above 1MeV. The particles studied here interact with metallic collectors and give signals due to several processes like secondary electron emission and lepton pair production (published). Two experimental facts are immediate: (1) the signal per sr at large distance is up to 10 times higher than at short distance, (2) the signal at large distance is faster in real time than at short distance. These results show directly that the signal at long distance is mainly due to a mixture of intermediate particles formed by decay in the beam. The decaying signals have time constants of approximately 12 and 26ns for ultra-dense deuterium D(0) and 52 ns for ultra-dense protium p(0). These decay time constants agree well with those for decay of light mesons. These particles with narrow MeV energy distributions are formed by stepwise decay from particles like HN(0). The main result is that a decaying particle flux is formed by the laser-induced processes. The final muons produced may be useful for muon catalyzed fusion.
TL;DR: In this article, the authors review the key concepts of collective neutrino oscillations by using a few simple toy models and elucidate the breaking of spatial and directional symmetries in these models because of collective oscillations.
Abstract: Neutrino oscillations in a hot and dense astrophysical environment such as a core-collapse supernova pose a challenging, seven-dimensional flavor transport problem. To make the problem even more difficult (and interesting), neutrinos can experience collective oscillations through nonlinear refraction in the dense neutrino medium in this environment. Significant progress has been made in the last decade towards the understanding of collective neutrino oscillations in various simplified neutrino gas models with imposed symmetries and reduced dimensions. However, a series of recent studies seem to have "reset" this progress by showing that these models may not be compatible with collective neutrino oscillations because the latter can break the symmetries spontaneously if they are not imposed. We review some of the key concepts of collective neutrino oscillations by using a few simple toy models. We also elucidate the breaking of spatial and directional symmetries in these models because of collective oscillations.
TL;DR: In this article, the authors studied the effects of anisotropic pressure on properties of the neutron stars with hyperons inside its core within the framework of extended relativistic mean field and found that the main effects of AI-P on NS matter is to increase the stiffness of the equation of state EOS, which compensates for the softening of the EOS due to the hyperons.
Abstract: We study the effects of anisotropic pressure (AI-P) on properties of the neutron stars (NSs) with hyperons inside its core within the framework of extended relativistic mean field. It is found that the main effects of AI-P on NS matter is to increase the stiffness of the equation of state EOS, which compensates for the softening of the EOS due to the hyperons. The maximum mass and redshift predictions of anisotropic neutron star with hyperonic core are quite compatible with the result of recent observational constraints if we use the parameter of AI-P model h ≤ 0.8 [L. Herrera and W. Barreto, Phys. Rev. D 88 (2013) 084022.] and Λ ≤ -1.15 [D. D. Doneva and S. S. Yazadjiev, Phys. Rev. D 85 (2012) 124023.]. The radius of the corresponding NS at M = 1.4 M⊙ is more than 13 km, while the effect of AI-P on the minimum mass of NS is insignificant. Furthermore, due to the AI-P in the NS, the maximum mass limit of higher than 2.1 M⊙ cannot rule out the presence of hyperons in the NS core.
TL;DR: In this paper, the effects due to lepton mass and its kinematic implications, radiative corrections, second class currents (SCCs) and uncertainties in the axial and pseudoscalar form factors are calculated for (anti)neutrino induced reaction cross-sections on free nucleon as well as the nucleons bound in a nucleus where nuclear medium effects influence the cross-section.
Abstract: In this paper, we have studied (anti)neutrino induced charged current quasielastic (CCQE) scattering from some nuclear targets in the energy region of Eν < 1GeV. Our aim is to confront electron and muon production cross-sections relevant for νμ↔νe or νμ↔νe oscillation experiments. The effects due to lepton mass and its kinematic implications, radiative corrections, second class currents (SCCs) and uncertainties in the axial and pseudoscalar form factors are calculated for (anti)neutrino induced reaction cross-sections on free nucleon as well as the nucleons bound in a nucleus where nuclear medium effects influence the cross-section. For the nuclear medium effects, we have taken some versions of Fermi gas model (FGM) available in the literature. The results for (anti)neutrino–nucleus scattering cross-section per interacting nucleons are compared with the corresponding results in free nucleon case.
TL;DR: In this paper, the rotational patterns for excitation energies, electromagnetic moments and electromagnetic transitions were investigated using ab initio rotational structure analysis for p-shell nuclei, and the robustness of rotational predictions across different choices for the internucleon interaction was highlighted.
Abstract: Through ab initio approaches in nuclear theory, we may now seek to quantitatively understand the wealth of nuclear collective phenomena starting from the underlying internucleon interactions. No-core configuration interaction (NCCI) calculations for p-shell nuclei give rise to rotational bands, as evidenced by rotational patterns for excitation energies, electromagnetic moments and electromagnetic transitions. In this review, NCCI calculations of 7–9Be are used to illustrate and explore ab initio rotational structure, and the resulting predictions for rotational band properties are compared with experiment. We highlight the robustness of ab initio rotational predictions across different choices for the internucleon interaction.
TL;DR: In this article, it was shown that the Unruh mechanism also predicts hadronic freeze-out conditions, giving in terms of the entropy density s and for the average energy per hadron.
Abstract: In this paper, we consider hadron production in high energy collisions as an Unruh radiation phenomenon. This mechanism describes the production pattern of newly formed hadrons and is directly applicable at vanishing baryon chemical potential, μ ≃ 0. It had already been found to correctly yield the hadronization temperature, in terms of the string tension σ. Here, we show that the Unruh mechanism also predicts hadronic freeze-out conditions, giving in terms of the entropy density s and for the average energy per hadron. These predictions provide a theoretical basis for previous phenomenological results and are also in accord with recent lattice studies.
TL;DR: In this paper, the elastic scattering angular distribution of triton is calculated by the obtained systematic helium-3 global optical model potential parameters and compared with the available experimental data, and the total reaction cross-sections are further investigated and the reasonable results are presented.
Abstract: The elastic scattering angular distributions of triton are calculated by the obtained systematic helium-3 global optical model potential parameters and compared with the available experimental data. These results show that the present global optical model potential can give a reasonable description of the elastic scattering of triton. The total reaction cross-sections of triton as a function of energy per nucleon are also further investigated and the reasonable results are presented.
TL;DR: In this paper, a phenomenological classification of collective quadrupole excitations by means of the Bohr-Hamiltonian (BH) is reviewed with focus on signatures for triaxility.
Abstract: The phenomenological classification of collective quadrupole excitations by means of the Bohr–Hamiltonian (BH) is reviewed with focus on signatures for triaxility. The variants of the microscopic BH derived by means of the Adiabatic Time-Dependent Mean Field theory from the Pairing-plus-quadrupole–quadrupole interaction, the Shell Correction Method, the Skyrme Energy Density Functional, the Relativistic Mean Field Theory and the Gogny interaction are discussed and applications to concrete nuclides reviewed. The Generator Coordinate Method for the five-dimensional quadrupole deformation space and first applications to triaxial nuclei are presented. The phenomenological classification in the framework of the Interacting Boson Model is discussed with a critical view on the boson number counting rule. The recent success in calculating the model parameters by mapping the mean field deformation energy surface on the bosonic one is discussed and the applications listed. A critical assessment of the models is given with focus on the limitations due to the adiabatic approximation. The Tidal Wave approach and the Triaxial Projected Shell Model are presented as practical approaches to calculate spectral properties outside the adiabatic region.
TL;DR: In this paper, the effects of the Tsallis distribution on physical quantities were studied using the linear sigma model in chiral phase transitions. But the authors focused on the effects on the energy and the critical temperature and energy density.
Abstract: The effects of the Tsallis distribution which has two parameters, q and T, on physical quantities are studied using the linear sigma model in chiral phase transitions. The Tsallis distribution approaches the Boltzmann–Gibbs distribution as q approaches one. The parameter T dependences of the condensate and mass for various q are shown, where T is called temperature. The critical temperature and energy density are described with digamma function, and the q dependences of these quantities and the extension of Stefan–Boltzmann limit of the energy density are shown. The following facts are clarified. The chiral symmetry restoration at q > 1 occurs at low temperature, compared with the restoration at q = 1. The sigma mass and pion mass reflect the restoration. The critical temperature decreases monotonically as q increases. The small deviation from the Boltzmann–Gibbs distribution results in the large deviations of physical quantities, especially the energy density. It is displayed from the energetic point of view that the small deviation from the Boltzmann–Gibbs distribution is realized for q > 1. The physical quantities are affected by the Tsallis distribution even when |q − 1| is small.
TL;DR: In this paper, a review and analysis of the models of the fundamental η-nucleon interaction leading to the formation of an η−mesic nucleus, the methods used in calculating the properties of a bound η, and the approaches employed in the interpretation of the pertinent experimental data is suggested.
Abstract: Eta-mesic nucleus or the quasibound nuclear state of an eta (η) meson in a nucleus is caused by strong interaction force alone. This new type of nuclear species, which extends the landscape of nuclear physics, has been extensively studied since its prediction in 1986. In this paper, we review and analyze in great detail the models of the fundamental η–nucleon interaction leading to the formation of an η–mesic nucleus, the methods used in calculating the properties of a bound η, and the approaches employed in the interpretation of the pertinent experimental data. In view of the successful observation of the η–mesic nucleus 25Mgη and other promising experimental results, future direction in searching for more η–mesic nuclei is suggested.
TL;DR: In this paper, the deuteron was probed at relative momenta beyond 300 MeV/c without dominating long-range effects and it was shown that at these large nucleon momenta the cross-section is sensitive to the nuclear dynamics at subfermi distances.
Abstract: We review the recent progress made in studies of deuteron structure at small internucleon distances. This progress is largely facilitated by the new generation of experiments in deuteron electrodisintegration carried out at unprecedentedly high momentum transfer. The theoretical analysis of these data confirms the onset of the high energy eikonal regime in the scattering process which allows one to separate long-range nuclear effects from the effects genuinely related to the short distance structure of the deuteron. Our conclusion is that for the first time the deuteron is probed at relative momenta beyond 300 MeV/c without dominating long-range effects. As a result, at these large nucleon momenta the cross-section is sensitive to the nuclear dynamics at subfermi distances. Due to large internal momenta involved we are dealing with the relativistic bound state that is best described by the light-cone momentum distribution of nucleons in the deuteron. We present the first attempt of extracting the deuteron light-cone momentum distribution function from data and discuss the importance of this quantity for studies of quantum chromodynamics (QCD) structure of the bound nucleon in deep inelastic scattering (DIS) off the deuteron. We conclude the review giving an outlook of the next generation of high energy experiments which will extend our reach to much smaller distances in the deuteron.
TL;DR: In this article, the importance of the Sp(3, ℝ) symmetry for a description of strongly interacting particles naturally emerges from the physical relevance of its generators, which directly relate to particle momentum and position coordinates, and represent important observables, such as, the manyparticle kinetic energy, the monopole operator, the quadrupole moment and the angular momentum.
Abstract: In this paper, we review recent developments that aim to achieve further understanding of the structure of atomic nuclei, by capitalizing on exact symmetries as well as approximate symmetries found to dominate low-lying nuclear states. The findings confirm the essential role played by the Sp(3, ℝ) symplectic symmetry to inform the interaction and the relevant model spaces in nuclear modeling. The significance of the Sp(3, ℝ) symmetry for a description of a quantum system of strongly interacting particles naturally emerges from the physical relevance of its generators, which directly relate to particle momentum and position coordinates, and represent important observables, such as, the many-particle kinetic energy, the monopole operator, the quadrupole moment and the angular momentum. We show that it is imperative that shell-model spaces be expanded well beyond the current limits to accommodate particle excitations that appear critical to enhanced collectivity in heavier systems and to highly-deformed spatial structures, exemplified by the second 0+ state in 12C (the challenging Hoyle state) and 8Be. While such states are presently inaccessible by large-scale no-core shell models, symmetry-based considerations are found to be essential.