Nuclear reaction studies of unstable nuclei using relativistic mean field formalisms in conjunction with the Glauber model
We study nuclear reaction cross sections for stable and unstable projectiles and targets within Glauber model, using densities obtained from various relativistic mean-field formalisms. The calculated cross sections are compared with the experimental data in some specific cases. We also evaluate the differential scattering cross sections at several incident energies and observe that the results found from various densities are similar at smaller scattering angles, whereas a systematic deviation is noticed at large angles. In general, these results agree fairly well with the experimental data.

title: Role of isospin physics in supernova matter and neutron stars
abstract: We investigate the liquid-gas phase transition of hot protoneutron stars shortly after their birth following supernova explosion and the composition and structure of hyperon-rich (proto)neutron stars within a relativistic mean-field model where the nuclear symmetry energy was constrained from the measured neutron skin thickness of finite nuclei. Light clusters are abundantly formed with increasing temperature well inside the neutrino-sphere for a uniform supernova matter. Liquid-gas phase transition is found to suppress the cluster yield within the coexistence phase as well as decrease considerably the neutron-proton asymmetry over a wide density range. We find symmetry energy has a modest effect on the boundaries and the critical temperature for the liquid-gas phase transition, and the composition depends more sensitively on the number of trapped neutrinos and temperature of the protoneutron star. The influence of hyperons in the dense interior of stars makes the overall equation of state soft. However, neutrino trapping distinctly delays the appearance of hyperons because of an abundance of electrons. We also find that a softer symmetry energy further makes the onset of hyperon less favorable. The resulting structures of the (proto)neutron stars with hyperons and with liquid-gas phase transition are discussed.

title: Exotic clustering in heavy and superheavy nuclei within the relativistic and non-relativistic mean field formalisms
abstract: The clustering phenomenon in heavy and superheavy nuclei is studied within the relativistic mean field (RMF) approach using axially deformed basis and the non-relativistic Skyrme?Hartree?Fock (SHF) formalism. The calculated ground and intrinsic excited state properties, and the total matter densities as well as the neutron?proton asymmetry distributions are analysed to look for the cluster configurations and/or exotic clusters in the known cluster emitting 222Ra, 232U, 236Pu and 242Cm nuclei, and the superheavy nuclei with Z = 114, N = 172?184. Both the theories predict N ? Z, ?-like matter or clustering in the ground states, and both N ? Z matter and N ? Z clustering in the excited intrinsic states of radioactive actinides, though this result is more apparent and universal for the RMF approach. For superheavy nuclei, the detailed analysis shows a non-clustering, 'bubble'-like structure for Z = 114, N = 184 nucleus in the RMF method and Z = 114, N = 176 or 180 nucleus in the SHF method, as the signatures of doubly closed shell nuclei. Our earlier similar calculations for Z = 120 nuclei predicted the same for Z = 120, N = 172 nucleus in the RMF model. Also, in contrast to radioactive actinides, in superheavy nuclei the two fragments, N ? Z cluster configurations at the centre of ground superdeformed states in the RMF approach, and the same for at least some of the excited superdeformed states in the SHF method, are some of the interesting results obtained. Thus, new possibilities of exotic clusters at the centre of superheavy nuclei are indicated as ground or excited intrinsic superdeformed state configurations, more so as ground superdeformed states in the RMF theory. The N/Z ratios of the clusters are also calculated on the basis of the (average value of) colour code of the contours, which give a reasonable correspondence with the experimental data on cluster decay of radioactive nuclei.

title: Axially-symmetric Neutron stars: Implication of rapid rotation
abstract: Models of relativistic rotating neutron star composed of hyperon rich matter is constructed in the framework of an effective field theory in the mean-field approach. The gross properties of compact star is calculated at both static and the mass-shedding limit in the axially symmetric basis. The effect of appearance and abundance of hyperons on equation of state of dense matter and stellar properties is lineated with particular emphasis on the underlying nuclear interactions. We find that the models can explain fast rotations, which supports the existence of millisecond pulsars. An important offshoot of the present investigation is that, irrespective of the model parameters and interaction taken, the star seems to sustain faster rotations (an increase in rotational frequency up to $\approx$ 50%) without any further deformation.

title: Superheavy nuclei in a relativistic effective Lagrangian model
abstract: Isotopic and isotonic chains of superheavy nuclei are analyzed to search for spherical double shell closures beyond Z= 82 and N= 126 within the new effective field theory model of Furnstahl, Serot, and Tang for the relativistic nuclear many-body problem. We take into account several indicators to identify the occurrence of possible shell closures, such as two-nucleon separation energies, two-nucleon shell gaps, average pairing gaps, and the shell correction energy. The effective Lagrangian model predicts N= 172 and Z= 120 and N= 258 and Z= 120 as spherical doubly magic superheavy nuclei, whereas N= 184 and Z= 114 show some magic character depending on the parameter set. The magicity of a particular neutron (proton) number in the analyzed mass region is found to depend on the number of protons (neutrons) present in the nucleus.

title: Phase transition and properties of a compact star
abstract: We investigate the phase transition to a deconfined phase and the consequences in the formation of neutron stars. We use the recently proposed effective-field-theory-motivated relativistic mean-field theory for the hadrons and the MIT bag model and color-flavor locked (CFL) phase for the quark matter to get the appropriate equation of state. The properties of the stars are then calculated. The differences between unpaired and CFL quark matter are discussed.

title: Theoretical Formulation of the Origin of Cataclysmic Late Heavy Bombardment Era based on the New Perspective of Birth & Evolution of Solar Systems
abstract: Based on the planet-satellite dynamics, a new perspective on the birth and evolution of the Solar System was proposed in 2004. This new perspective has 1:2 Mean Motion Resonance (1:2 MMR, that is Ps/Pj = 2) implicit in itself . This paper has shown that if we assume the sequential birth of the planets with the heaviest, i.e. Jupiter, being born the earliest and this axiom is central to the new perspective then there is an unique initial condition for which 1:2 MMR crossing occurs exactly 300My after the birth of Jupiter. It is shown that 25 My time gap between the birth of Jupiter and Saturn results in the 300 My time delay in the occurrence of 1:2 MMR. Because the process by which Late Heavy Bombardment is triggered involves the movement of Neptune over enormous distances hence almost 200 My time delay occurs between 1:2MMR crossing and the actual spike in the Meteoritic Shower on all the terrestrial planets as evidenced by the petrology record on the Moon. The analytical derivation of the time delay in the spike is a vindication of this new perspective of the application of planet-satellite dynamics to the birth and evolution of Solar Systems.

title: The Architectural Design Rules of Solar Systems Based on the New Perspective
abstract: In this paper I present a new perspective of the birth and evolution of Planetary Systems. This new perspective presents an all encompassing and self consistent Paradigm of the birth and evolution of the solar systems. In doing so it redefines astronomy and rewrites astronomical principles. Kepler and Newton defined a stable and non-evolving elliptical orbits. While this perspective defines a collapsing or expanding spiral orbit of planets except for Brown Dwarfs. Brown Dwarfs are significant fraction of the central star. Hence they rapidly evolve from non-Keplerian state to the end point which is a Keplerian state where it is in stable elliptical orbits. On the basis of the Lunar Laser Ranging Data released by NASA on the Silver Jubilee Celebration of Man’s Landing on Moon on 21st July 1969–1994, theoretical formulation of Earth-Moon tidal interaction was carried out and Planetary Satellite Dynamics was established. It was found that this mathematical analysis could as well be applied to Star and Planets system and since every star could potentially contain an extra-solar system, hence we have a large ensemble of exo-planets to test our new perspective on the birth and evolution of solar systems. Till date 403 exo-planets have been discovered in 390 extra-solar systems by radial velocity method, by transiting planet method, by gravitational lensing method, by direct imaging method and by timing method. I have taken 12 single planet systems, four Brown Dwarf—Star systems and two Brown Dwarf pairs. Following architectural design rules are corroborated through this study of exo-planets. All planets are born at inner Clarke’s Orbit what we refer to as inner geo-synchronous orbit in case of Earth-Moon System. The inner Clarke’s Orbit is an orbit of unstable equilibrium. By any perturbative force such as cosmic particles or radiation pressure, the planet gets tipped long of aG1 or short of aG1. Here aG1 is inner Clarke’s Orbit. If planet is long of aG1 then it is said to be in extra-synchronous orbit. Here Gravitational Sling Shot effect is in play. In gravity assist planet fly-by maneuver in space flights, gravitational sling shot is routinely used to boost the space craft to its destination. The exo-planet can either be launched on death spiral as CLOSE HOT JUPITERS or can be launched on an expanding spiral path as the planets in our Solar System are. In death spiral, exo-planet less than 5 mJ will get pulverized and vaporized in close proximity to the host star. If the mass is between 5 and 7.5 mJ then it will be partially vaporized and partially engulfed by the host star and if it is greater than 7.5 mJ, then it will be completely ingested by the host star. In the process the planet will deposit all its material and angular momentum in the Host Star. This will leave tell-tale imprints of ingestion: in such cases host Star will have higher 7Li, host star will become a rapidly rotating progenitor and the host star will have excess IR. All these have been confirmed by observations of Transiting Planets. It was also found that if the exo-planet are significant fraction of the host star then those exo-planets rapidly migrate from aG1 to aG2 and have very short Time Constant of Evolution as Brown Dwarfs have. But if exo-planets are insignificant fraction of the host star as our terrestrial planets are then they are stay put in their original orbit of birth. By corollary this implies that Giant exo-planets reach nearly Unity Evolution Factor in a fraction of the life span of a solar system. This is particularly true for brown dwarfs orbiting main sequence stars. In this study four star systems hosting Brown Dwarfs, two Brown Dwarf pairs and 12 extrasolar systems hosting Jupiter sized planets are selected. In Brown Dwarfs evolution factor is invariably UNITY or near UNITY irrespective of their respective age and Time Constant of Evolution is very short of the order of year or tens of years. In case of 12 exo-planets system with increasing mass ratio evolution factor increases and time constant of evolution shortens from Gy to My though there are two exceptions. TW Hydrae is a special case. This Solar System is newly born system which is only 9 million years old. Hence its exo-planet has just been born and it is very near its birth place just as predicted by my hypothesis. In fact it is only slightly greater than aG1. This vindicates our basic premise that planets are always born at inner Clarke’s Orbit. This study vindicates the design rules which had been postulated at 35th COSPAR Scientific Assembly in 2004 at Paris, France, under the title “New Perspective on the Birth & Evolution of Solar Systems”.