International Journal of Modern Physics E

Deconfinement refers to the creation of a state of quasi-free quarks and gluons in strongly interacting matter. Model predictions and experimental evidence for the onset of deconfinement in nucleus–nucleus collisions were discussed in our first review on this subject. These results motivated further experimental and theoretical studies. This review addresses two subjects. First, a summary of the past, present and future experimental programmes related to discovery and study of properties of the onset of deconfinement are presented. Second, recent progress is reviewed on analysis methods and preliminary experimental results for new strongly intensive fluctuation measures are discussed, which are relevant for current and future studies of the onset of deconfinement and searches for the critical point of strongly interacting matter.

A brief review of the Francium trapping experiments at the INFN-LNL facility is presented in the wide context of Atomic Parity-Nonconservation (APNC), which, as long as acquiring more precise and new spectroscopic data on the Francium isotopes, is the ultimate goal of the experiment. Due to its instability, Francium atoms must be produced continuously by a nuclear fusion–evaporation reaction into a heated Gold target hit by a beam of accelerated oxygen ions. Francium is then extracted in the ionic form and guided by an electrostatic line to the actual science chamber, where the ions are neutralized. Atoms are then cooled down and trapped in a Magneto-Optical Trap (MOT) to ensure both the availability of a sufficiently populated and stable atomic sample and to eliminate the Doppler broadening which would affect the precision of the measurements. A review of the recent improvements to the experimental apparatus and to the detection techniques that led to a sensitivity better than five atoms is presented. The final part of this paper deals with a summary of the recent results obtained by our collaboration and a short outlook for the immediate future.

We briefly comment upon the parallel between graphene and high energy fermions and explore the possibility of using the former as a test bed for the latter. We also point out that there are parallels to quantum gravity approaches, which indeed provide a novel explanation for such effects as the Fractional Quantum Hall Effect (FQAE).

We extend our Skyrme–Hartree–Fock (SHF) approach, which was used earlier to describe successfully the single-Λ hypernuclei, to investigate the binding and the ΛΛ bond energies of the double-Λ hypernuclei. The nucleon–nucleon (NN) and Λ-nucleon (ΛN) interactions are taken from our previous study. For the ΛΛ force, several Skyrme-like potentials available in the literature have been used. We discuss the sensitivity of the calculated ΛΛ binding and bond energies to the ΛΛ and ΛN force parameters. It is found that the existing ΛΛ hypernuclear data do not allow to distinguish between various ΛΛ force parameter sets used by us. However, they show some selectivity for a particular set of the ΛN potential determined in our previous work.

Presence of unusual azimuthal structures in the particle emission data obtained from the ²⁸Si–Ag/Br interaction at 14.5A GeV and from the ³²S–Ag/Br interaction at 200A GeV, are investigated in the framework of the Cherenkov gluon emission and/or Mach shock wave formation in nuclear/partonic medium. Nuclear photographic emulsion technique is used to collect the experimental data. The experiment is compared with the predictions of two simulations, namely (i) the Relativistic Quantum Molecular Dynamics (RQMD) and (ii) the Ultra-relativistic Quantum Molecular Dynamics (UrQMD). A charge reassignment algorithm is implemented over the outputs of the simulations to mimic the Bose–Einstein correlation (BEC) effect. Our analysis confirms presence of jet-like structures in both experiments beyond statistical noise. Such structures are more pronounced in the ³²S data than in the ²⁸Si data.

We calculate, here, the electromagnetic (em) neutron–proton mass difference analytically by using arctan ansatz in Skyrme model. The value so obtained is compared with those given in the literature. Our value agrees well with the widely accepted value in the literature.

Effect of the jet production on the multiplicity distribution (MD) of secondary charged particles produced in pp-collisions at 1.8 TeV is studied using the HIJING code. The charged particles MDs for a whole polar angle range and for six polar angular regions as a function of different number of jets were analyzed. The obtained simulation results were compared with experimental MDs coming from the Tevatron and SPS experiments. The increasing behavior of multiplicity of the secondary charged particles influenced by multi-jet events is discussed.

The decay of ²²⁰Ra* nucleus formed in two different entrance channels ¹²C+²⁰⁸Pb and ¹³C+²⁰⁷Pb is investigated over a wide range of incident energies using the dynamical cluster decay model (DCM). The DCM is a non-statistical model used to account for the decay of hot and rotating nuclei formed in low energy heavy ion reactions. The excitation functions are calculated by considering quadrupole (β₂) deformations with optimum orientations of decaying fragments. The DCM-based cross-sections for evaporation residue (ER), fusion–fission, αxn and neutron decay processes find nice agreement with the reported experimental data over wide range of incident energies. The cross-sections corresponding to different decay mechanism are worked out within DCM by fitting neck length parameter (ΔR). The entrance channel and angular momentum effects are investigated in reference to the above-mentioned reaction channels. In addition to this, the fragment mass distribution is worked out by colliding ¹³C weakly bound stable projectile with a variety of target nuclei resulting in ¹³C+¹⁵⁹Tb, ¹³C+¹⁸¹Ta and ¹³C+²⁰⁷Pb reactions. At comparable projectile energies, the increase in target mass is shown to favor asymmetric fragmentation in the fissioning region. Besides this, the incomplete fusion (ICF) contribution is worked out for ¹²C and ¹³C channels by applying necessary energy corrections in the framework of DCM.

Starting from an effective model of asymmetric nuclear matter we show that at finite temperature T and baryon chemical potential μ_B there exists a topological phase transition from state of non-Fermi liquid to that of Fermi liquid which is protected by winding numbers. At low μ_B the transition is first-order, then extends to a second-order phase transition at larger μ_B through a tri-critical point. The isospin dependences of the tri-critical point and the phase diagram in the (T, μ_B)-plane are established. The distinction between this type of phase transition and the similar phenomenon caused by the Silver Blaze property (SBP) at T = 0 is confirmed for isospin varying from 0 to 1. We reveal that the topological phase transition could emerge in a large class of nuclear theories.

Low-energy protons from the cyclotron in the range of 15–30 MeV and low current have been simulated on beryllium (Be) target with a lead moderator around the target. This research was accomplished to design an epithermal neutron beam for Boron Neutron Capture Therapy (BNCT) using the moderated neutron on the average produced from ⁹Be target via (p, xn) reaction in Adiabatic Resonance Crossing (ARC) concept. Generation of neutron to proton ratio, energy distribution, flux and dose components in head phantom have been simulated by MCNP5 code. The reflector and collimator were designed in prevention and collimation of derivation neutrons from proton bombarding. The scalp-skull-brain phantom consisting of bone and brain equivalent material has been simulated in order to evaluate the dosimetric effect on the brain. Results of this analysis demonstrated while the proton energy decreased, the dose factor altered according to filters thickness. The maximum epithermal flux revealed using fluental, Fe and bismuth (Bi) filters with thicknesses of 9.4, 3 and 2 cm, respectively and also the epithermal to thermal neutron flux ratio was 103.85. The potential of the ARC method to replace or complement the current reactor-based supply sources of BNCT purposes.

The shape and position of the plasma and consequently the plasma boundary are determined by using the Current Filament (CF) method from the experimental data of the magnetic measurements in Damavand tokamak. The method can calculate the magnetic flux without solving the equilibrium equation directly by coupling with the Current Moment (CM) method. The plasma and current-carrying coils in the tokamak will be modeled by using this method as some virtual filaments that will enable us to calculate the flux and consequently the plasma boundary. To calculate the flux of these virtual filaments, one needs to determine the Green Function and the inverse by means of the Singular Value Decomposition (SVD) method. Finally, the model was evaluated by employing 12 independent pickup coils with mean error of less than 2%. The aim of this paper is to give a brief exposition of CF method applied in Damavand tokamak.

The energy levels of excited states of ground state, β- and γ-bands of the lanthanide and actinide even–even nuclei have been studied within the Davydov–Chaban model (for three different types of the potential energy of the β-deformations) and approximations for a small and free triaxiality. It is shown that the approximation with a free triaxiality better describes the spectrum of the excited collective states for considered nuclei.