120695709
Strong influence of the entrance channel on the formation of compound nuclei Th216,222* and their evaporation residues
The dynamical effects of the entrance channel on the formation of the evaporation residues are studied by analyzing the $^{40}\mathrm{Ar}+^{176}\mathrm{Hf}$, $^{86}\mathrm{Kr}+^{130,136}\mathrm{Xe}$, $^{124}\mathrm{Sn}+^{92}\mathrm{Zr}$, and $^{48}\mathrm{Ca}+^{174}\mathrm{Yb}$ reactions leading to the $^{216}\mathrm{Th}{}^{*}$ and $^{222}\mathrm{Th}{}^{*}$ compound nuclei. We find that the difference between the evaporation residue cross sections for the reactions leading to the same compound nucleus is caused by the different angular momentum distributions of the partial fusion cross sections ${\ensuremath{\sigma}}_{\mathrm{fus}}^{\ensuremath{\ell}}({E}_{c.m.})$. The strong dependence of the fusion angular momentum distribution on the mass (charge) asymmetry and shell structure of reactants is demonstrated. The effect of the $A/Z$ ratio for the $^{86}\mathrm{Kr}+^{130,136}\mathrm{Xe}$ reactions is discussed. The dynamical conditions of capture affect the competition between complete fusion and quasifission and, consequently, the shape of the angular momentum distribution of the compound nucleus. By this way the peculiarities of the entrance channel also affect the fission-evaporation competition of the excited intermediate nuclei along the deexcitation cascade of the compound nucleus and, consequently, the evaporation residue formation.
172282907
Production and stability of new elements
201093324
Proton Radioactivity
120335892
Study of SHE at the GSI-SHIP
Abstract An overview of present experimental investigation of superheavy elements is given. Using cold fusion reactions which are based on lead and bismuth targets, relatively neutron deficient isotopes of the elements from 107 to 113 were synthesized at GSI in Darmstadt, Germany, and/or at RIKEN in Wako, Japan. In hot fusion reactions of 48 Ca projectiles with actinide targets more neutron rich isotopes of the elements from 112 to 116 and even 118 were produced at FLNR in Dubna, Russia. Recently, part of these data, which represent the first identification of nuclei located on the predicted island of SHEs, were confirmed in two independent experiments. The data are compared with theoretical descriptions.
123051492
The velocity filter ship, a separator of unslowed heavy ion fusion products
The velocity filter SHIP installed at the UNILAC (GSI Darmstadt) is described. It is used for the investigation of neutron deficient nuclei generated by heavy ion induced fusion. The two stage filter separates unretarded reaction products emerging from a thin target with high efficiency and low background of primary beam particles. For reaction products covering an angular range of 3° in horizontal and vertical directions and a velocity range of 10% the transmission is between 30% and 60%. The separation time is of the order of 10−6s. High suppression of primary particles by factors of 107-1011 permits the investigation of reaction products in the direction of the primary beam. α-active reaction products have been implanted into a surface barrier detector and identified by their decay. 
 
A description of the ion optical principles, technical details and the performance of SHIP is given.
122536153
Formation of superheavy elements in cold fusion reactions
The process of the synthesis of superheavy elements ~SHEs! is not yet understood completely. In the presented work we make an attempt to describe the cold fusion reactions of the type X1(Pb,Bi)→SHE 11n at subbarrier energies. The process of the formation of SHEs is subdivided into three steps. ~1! The capture of two spherical nuclei and the formation of a common shape of the two touching nuclei. Low-energy surface vibrations and transfer of few nucleons are taken into account in the first step of the reaction. ~2! The formation of a spherical or near spherical compound nucleus. ~3! The survival of the excited compound nucleus due to evaporation of neutrons and g-ray emission in competition with fission. A lowering of the fission barrier was taken into account, which arises from a reduction of shell effects at increasing excitation energy of the compound nucleus. The following reactions were analyzed in detail: (Fe, Ni, Zn, Ge)1Pb, (Ti, Cr, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se)1Pb, (Fe, Ni, Zn, Ge) 1Pb, and (Ti, Cr, Fe, Ni, Zn, Ge)1Bi. The presented model describes well the available experimental cross-section data and allows for predicting cross-section values for the synthesis of so-far unknown heavier elements.
20326557
Brane Induced Gravity, its Ghost and the Cosmological Constant Problem
Brane Induced Gravity is regarded as a promising framework for addressing the cosmological constant problem, but it also suffers from a ghost instability for parameter values that make it phenomeno ...
119225428
Cascading gravity and degravitation
We construct a cascading brane model of gravity in which the behavior of the gravitational force law interpolates from (n+4)-dimensional to (n+3)-dimensional all the way down to 4-dimensional from longer to shorter length scales. We show that, at the linearized level, this model exhibits the features necessary for degravitation of the cosmological constant. The model is shown to be ghost free with the addition of suitable brane kinetic operators, and we demonstrate this using a number of independent procedures. Consequently this is a consistent infrared (IR) modification of gravity, providing a promising framework for a dynamical, degravitating solution of the cosmological constant problem.
37255447
A Quantum Bound-State Description of Black Holes
A relativistic framework for the description of bound states consisting of a large number of quantum constituents is presented, and applied to black-hole interiors. At the parton level, the constituent distribution, number and energy density inside black holes are calculated, and gauge corrections are discussed. A simple scaling relation between the black hole mass and constituent number is established.
17693958
Discrete energy spectrum of Hawking radiation from Schwarzschild surfaces
We analyze the allowed energy levels of Hawking radiation from Schwarzschild surfaces in space-times with large extra dimensions. From the requirement that the wave functions associated with these particles be single-valued and obey radial boundary conditions, we derive an upper bound of their discrete energy spectrum as a function of the number of large extra dimensions and the mass of the black hole. Furthermore, we investigate the spacing of the energy levels.
33743720
Small-scale structure of cold dark matter
Abstract We investigate the clumping of cold dark matter (CDM) at small scales. If the CDM particle is the neutralino, we find that collisional damping during its kinetic decoupling from the radiation fluid and free streaming introduce a small-scale cut-off in the primordial power spectrum of CDM. This cut-off sets the scale for the very first CDM objects in the Universe, which we expect to have a mass of ∼10 −12 M ⊙ . For non-thermal CDM candidates, such as axions, wimpzillas, or primordial black holes, the cosmological QCD transition might induce features in the primordial spectrum at similar mass scales.