International Journal of Modern Physics E

The conservation of electric charge Q is a universal law in the sense that it should be conserved in any interaction, known or yet unknown. However, Q should not be considered as a simple number but as the half sum of two irreducible quantities, the baryon lepton asymmetric number BAL = A-L (where A is the baryonic number and L is the leptonic number) and total flavor TF. Conservation of electric charge implies obviously conservation of Q (considered as a simple number) but also BAL and TF. We verify that electromagnetism and strong interaction which conserve Q, A and L and all individual flavors conserve obviously BAL and TF; that weak interaction which conserves Q, A and L conserves also BAL and TF. However, conservation of BAL does not necessarily imply conservation of A and L. In effect Δ BAL = 0 has another solution ΔA = ΔL = ±1 which points to a possible solution to explain how a material and neutral universe could arise evolving from an A = 0, L = 0, Q = 0 state to an A > 0, Q = 0 state through a process which would conserve BAL and TF without conserving separately A and L.

The holographic principle (HP) conjectures, that the maximum number of degrees of freedom of any realistic physical system is proportional to the system's boundary area. The HP has its roots in the study of black holes. It has recently been applied to cosmological solutions. In this article we apply the HP to spherically symmetric static space-times.

We find that any regular spherically symmetric object saturating the HP is subject to tight constraints on the (interior) metric, energy-density, temperature and entropy-density. Whenever gravity can be described by a metric theory, gravity is macroscopically scale invariant and the laws of thermodynamics hold locally and globally, the (interior) metric of a regular holographic object is uniquely determined up to a constant factor and the interior matter-state must follow well defined scaling relations. When the metric theory of gravity is general relativity, the interior matter has an overall string equation of state (EOS) and a unique total energy-density. Thus the holographic metric derived in this article can serve as simple interior 4D realization of Mathur's string fuzzball proposal.

Some properties of the holographic metric and its possible experimental verification are discussed. The geodesics of the holographic metric describe an isotropically expanding (or contracting) universe with a nearly homogeneous matter-distribution within the local Hubble volume. Due to the overall string EOS the active gravitational mass-density is zero, resulting in a coasting expansion with Ht = 1, which is compatible with the recent GRB-data.

A new formulation of field theory is presented, based on a pseudo-complex description. An extended group structure is introduced, implying a minimal scalar length, rendering the theory regularized a la Pauli–Villars. Cross sections are calculated for the scattering of an electron at an external Coulomb field and the Compton scattering. Deviations due to a smallest scalar length are determined. The theory also permits a modification of the minimal coupling scheme, resulting in a generalized dispersion relation. A shift of the Greisen–Zatsepin–Kuzmin (GZK) limit of the cosmic ray spectrum is the consequence.

Two approaches to renormalization-group improvement are examined: the substitution of the solutions of running couplings, masses and fields into perturbatively computed quantities is compared with the systematic sum of all the leading log (LL), next-to-leading log (NLL) etc. contributions to radiatively corrected processes, with n-loop expressions for the running quantities being responsible for summing N^n-1LL contributions. A detailed comparison of these procedures is made in the context of the effective potential V in the 4-dimensional O(4) massless λϕ⁴ model, showing the distinction between these procedures at two-loop order when considering the NLL contributions to the effective potential V.

In the light of ideas of the nonextensive thermodynamics, we have analyzed here the transverse momentum spectra of pions and protons produced at different centralities in the interactions of P+P, D+Au and Au+Au interactions, all of them at GeV at RHIC-BNL. Comparison of the results and the comments thereon have also been made with indications of suitable hints to the physical import and implications. The overall impact and the utility of the approach along with the obtained results are discussed in detail.

In this paper we estimate the influence of the shadowing effect and initial state parton energy loss in the quarkonium production at HERA-B. We analyze the x_F behavior of the effective exponent α(x_F) and present a comparison with the preliminary HERA-B data for J/Ψ production. Moreover, we estimate the magnitude of these effects in the J/Ψ production at RHIC.

The structure of the isoscalar giant dipole resonance (ISDGR) in ²⁰⁸Pb has been investigated by using the continuum Randon Phase Aproximation (RPA). The main properties (strength function and escape widths) of the ISDGR are calculated and compared with recent available experimental data.

Clustering structures of the various resonance states of the compound nucleus ⁴⁷⁶184^*, formed in ²³⁸U+²³⁸U reaction, are studied within the standard relativistic mean field (RMF) and non-relativistic Skyrme Hartree–Fock formalisms. The formations of various possible clusters and superheavy nuclei as daughter products are discussed. Both the formalisms support clustering phenomenon, the RMF presenting a somewhat more realistic picture. Also, before the asymptotic fissioning state, a kind of triple fission, with the cluster appearing in the neck region of two equal fragments, is obtained as one of the possibilities in RMF formalism.

This paper presents an experiment with the 2×2 inch NaI(Tl) detector to measure the internal bremsstrahlung of ⁹⁰Sr-⁹⁰Y in equilibrium beta particle emitters using the beta-stopper method in the range 10–1750 keV. The Gold algorithm is applied to unfold the internal bremsstrahlung spectrum of ⁹⁰Sr-⁹⁰Y beta source. Unfolded IB spectrum is compared with the KUB theory. There is good agreement between the theory and the unfolded measured spectrum in the energy range below 1000 keV. Beyond this energy, there are discrepancies between the theory and unfolded spectrum.

Working within the framework of Coulomb modified correlation expansion of the Glauber amplitude, we analyse the elastic scattering of ~1 GeV protons on ⁴He, ¹²C, ¹⁶O and ⁴⁰Ca nuclei. Emphasis has been put on the use of different parametrizations of the basic (input) NN amplitude, which provide equivalently good accounts of the elastic NN scattering observables up to the available momentum transfer region. Using realistic form factors for target nuclei, it is found that the proton-nucleus collisions could provide a test to know which is the better choice of the NN amplitude. The analysis also considers the possibility of extracting some additional information about the matter density distributions.

We consider a semiclassical model of light nuclei, where the nucleus has a crystal-like shape and is built solely from α-particles. We analyze the role of linear configurations in this model, which correspond to super-deformed nuclei. The strong deformed shape for the doubly even nuclei from ¹²C to ²⁴Mg has been determined according to this model. The obtained results show a good agreement with the experimental data.

Pseudorapidity density distributions of relativistic charged particles produced in ²⁸Si-induced interactions in nuclear emulsion at JINR Synchrophasotron have been measured. The particle distributions in minimum-bias events exhibit a pronounced forward asymmetry with respect to the peak in the pseudorapidity spectra. The effect of intranuclear collisions on the mean pseudorapidity distribution versus the shower particles (n_s) or the grey particles is discussed and compared with similar studies of ²⁸Si and ³²S at BNL AGS and CERN SPS energies respectively.

The influence of the final-state NN- and πN-rescattering on double polarization cross sections for the exclusive reaction , involving polarization of the photon beam and the deuteron target, is investigated in the Δ(1232)-resonance region. We found that the effect of NN-rescattering is quite important, whereas the contribution from πN-rescattering is found to be negligible. Sizeable effects, mainly from the NN-rescattering, are found leading to an appreciable reduction of the polarized cross sections. In addition, the effect of final state interactions on the beam-target double polarization E asymmetry is investigated. In contrast to the polarized cross sections, these effects are found to be very small in case of the E asymmetry.