International Journal of Modern Physics E

We review the interface between the current theoretical framework based on generalized parton distributions (GPDs) and experimental measurements of deeply virtual Compton scattering (DVCS) observables. We find that the present theoretical framework needs to be extended to cover the current and future DVCS experiments. The current formulation is based on the quantum chromodynamics factorization of the handbag diagrams, relying on handbag dominance. Our examination reveals that the handbag diagrams by themselves do not satisfy electromagnetic gauge invariance. Our numerical estimates of the DVCS amplitudes in a solvable model indicate that the handbag contribution is not sufficient to saturate the exact result. Assuming the extraction of GPDs is made, we analyzed the crossover point in GPDs, important for the single spin asymmetry seen in DVCS experiments. We found that the inclusion of the higher Fock states is essential to explain the available data of single spin asymmetry.

In this brief review of the observable effects of minijets in heavy-ion collisions, the main points emphasized are that the quadruple moment v₂(p_T, b) and the hadronic (π and p) spectra at low p_T can both be reproduced by minijet contributions to the recombination of thermal and shower partons. Without using hydrodynamics the minijet approach does not trace the evolution of the expanding system. The thermal distribution of the medium partons at the time of hadronization is assumed, but rapid thermalization initially is not required so as to allow minijets to leave their footprints on the system in the final state. Azimuthal anisotropy due to minijets is directly calculated in the momentum space without any fluid assumption relating the spatial eccentricity to v₂. There are no more parameters used and compared to the hydro approach in fitting the data on v₂ and p_T spectra. Thus both approaches satisfy the sufficiency condition for a viable description of the dynamical process involved.

We review the theoretical and experimental current status of the H dibaryon. We revise the recent experimental results obtained from double-Λ hypernuclei produced by means of Ξ-capture reactions using different target nuclei. Forthcoming experimental projects are briefly summarized. We also review the recent theoretical quark-model studies, some of them constrained by observables of the strangeness -2 two-baryon sector. Ongoing theoretical efforts by means of lattice QCD are also discussed.

We study the half-lives of some Pt isotopes via the alpha-decay process and a modified barrier penetration formula different from the traditional barrier potentials. Comparison with the existing data is quite motivating.

The estimate of the energy deposition rate (EDR) for neutrino pair annihilation has been carried out. The EDR for the neutrinos coming from the equatorial plane of a rotating neutron star is calculated along the rotation axis using the Cook–Shapiro–Teukolsky metric. The neutrino trajectories and hence the neutrinos emitted from the disk are affected by the redshift due to disk rotation and gravitation. The EDR is very sensitive to the value of the temperature and its variation along the disk. The rotation of the star has a negative effect on the EDR; it decreases with increase in rotational velocity.

Using HF+BCS method with Skyrme forces we analyze the neutron drip line. It is shown that the drip line may form stability peninsulas. These peninsulas locate along fixed neutron numbers on the nuclear chart, which correspond to magic and new magic numbers, and are the same for all Skyrme forces. It is found that the size of the peninsulas is sensitive to the choice of Skyrme forces and the most extended peninsulas appear with the SkI2 set.

We assume a simple model to describe the ion–ion potential with dynamical change in its surface diffuseness. In particular, this model is used to calculate the heavy-ion fusion cross-section using different values of the surface diffuseness. Both the static and dynamic nuclear Woods–Saxon potentials with diffuseness values ranging between 0.65 fm and 1.3 fm are used to reproduce the fusion cross-sections data of the ¹⁹F+²⁰⁸Pb and ¹⁶O+¹⁵⁴Sm reactions. The results estimate that there are different physical processes which could contribute to the fusion cross-section with different weights at each energy value. Each of these processes has its own nuclear potential.

In this work, the response functions (RFs) of the ⁴He, ¹⁶O and ⁴⁰Ca nuclei are calculated in the harmonic oscillator shell model (HOSM) and the impulse approximation (IA). First, the one-body momentum distribution and the one-body spectral functions for these nuclei are written in the HOSM configuration. Then, their RFs are calculated, in the two frameworks, namely the spectral and the momentum distribution functions, within the IA. Unlike our previous work, no further assumption is made to reduce the analytical complications. For each nucleus, it is shown that the (RF) evaluated using the corresponding spectral function has a sizable shift, with respect to the one calculated in terms of the momentum distribution function. It is concluded that for the heavier nuclei, this shift increases and reaches nearly to a constant value (approximately 62 MeV), i.e., similar to that of nuclear matter. It is discussed that in the nuclei with the few nucleons, the above shift can approximately be ignored. This result reduces the theoretical complication for the explanation of the ongoing deep inelastic scattering (DIS) experiments of ³H or ³H nucleus target in the Jefferson Laboratory. On the other hand, it is observed that in the heavier nuclei, the RF heights (width) decrease (increase), i.e., the comparison between the theoretical and the experimental electron nucleus scattering cross-section is more sensible for heavy nuclei rather than the light ones.