Eden growth model for aggregation of charged particles

The stochastic Eden model of charged particles aggregation in two-dimensional systems is presented. This model is governed by two parameters: screening length of electrostatic interaction, $\lambda$, and short range attraction energy, $E$. Different patterns of finite and infinite aggregates are observed. They are of following types of morphologies: linear or linear with bending, warm-like, DBM (dense-branching morphology), DBM with nucleus, and compact Eden-like. The transition between the different modes of growth is studied and phase diagram of the growth structures is obtained in $\lambda, E$ co-ordinates. The detailed aggregate structure analysis, including analysis of their fractal properties, is presented. The scheme of the internal inhomogeneous structure of aggregates is proposed.Comment: Revtex, 9 pages with 12 postscript figure

Deterministic growth model of Laplacian charged particle aggregates

The results of the computer simulation of the aggregates growth of the similarly charged particles in the framework of deterministic Laplacian growth model on a square lattice are presented. Cluster growth is controlled by three parameters ${p, E,\lambda}$, where $p$ - Laplacian growth parameter, $E$ - energy of a particle sticking to a cluster, $\lambda$ - the screening length of electrostatic interactions. The phase diagram of cluster growth is built in the co-ordinates ${E,\lambda}$. The zones of different cluster morphology are selected: I-the zone of finite X-like structures,II-the zone of infinite ramified structures, controlled by electrostatic interactions, III-the zone of infinite structures with electrostatic interactions effectively switched off. Simple electrostatic estimations of the locations of the zone boundaries are presented. It is shown that in general case within the zone II the continuous change of $D_f$, controlled by parameters ${p, E,\lambda}$, takes place. In the degeneration limit when the given model transforms into deterministic version of the Eden model (at $p=0$), the crossover from linear $(D_f=1)$ to compact $(D_f=2)$ structures is observed when passing through the boundary between the zones I and II.Comment: REVTEX, 3 pages with 4 postscript figure

Lateral-angular and temporal characteristics of EAS optical radiation

Characteristics of the direct and scattered components of electron-photon shower optical radiation for distances R 500 m from the shower core to a detector, allowing for the Cerenkov and fluorescent mechanism of photon generation are presented. The results of calculations are employed to clarify the techniques for determination of the shower parameters detected by both installations registering fluorescent light and those recording Cerenkov light

Analytical-numerical methods of calculations of energy and three-dimensional particle distributions in electromagnetic cascades

Analytical and numerical methods of calculation of the energy and three dimensional EPS characteristics are reported. The angular and lateral functions of electrons in EPS have been obtained by the Landau and small angle approximations A and B and compared with earlier data. A numerical method of solution of cascade equations for the EPS distribution function moments has been constructed. Considering the equilibrium rms angle as an example, errors appearing when approximating the elementary process cross sections by their asymptotic expressions are analyzed

Sensitivity of depth of maximum and absorption depth of EAS to hadron production mechanism

Comparison of experimental data on depth of extensive air showers (EAS) development maximum in the atmosphere, T sub M and path of absorption, lambda, in the lower atmosphere of EAS with fixed particle number in the energy region eV with the results of calculation show that these parameters are sensitive mainly to the inelastic interaction cross section and scaling violation in the fragmentation and pionization region. The data are explained in a unified manner within the framework of a model in which scaling is violated slightly in the fragmentation region and strongly in the pionization region at primary cosmic rays composition close to the normal one and a permanent increase of inelastic interaction cross section. It is shown that, while interpreting the experimental data, disregard of two methodical points causes a systematic shift in T sub M: (1) shower selection system; and (2) EAS electron lateral distribution when performing the calculations on basis of which the transfer is made from the Cerenkov pulse FWHM to the depth of shower maximum, T sub M

Color-flavor locked superconductor in a magnetic field

We study the effects of moderately strong magnetic fields on the properties of color-flavor locked color superconducting quark matter in the framework of the Nambu-Jona-Lasinio model. We find that the energy gaps, which describe the color superconducting pairing as well as the magnetization, are oscillating functions of the magnetic field. Also, we observe that the oscillations of the magnetization can be so strong that homogeneous quark matter becomes metastable for a range of parameters. We suggest that this points to the possibility of magnetic domains or other types of magnetic inhomogeneities in the quark cores of magnetars.Comment: 12 pages, 3 figures. Version accepted for publication in Phys. Rev.

Common vacuum conservation amplitude in the theory of the radiation of mirrors in two-dimensional space-time and of charges in four-dimensional space-time

The action changes (and thus the vacuum conservation amplitudes) in the proper-time representation are found for an accelerated mirror interacting with scalar and spinor vacuum fields in 1+1 space. They are shown to coincide to within the multiplier e^2 with the action changes of electric and scalar charges accelerated in 3+1 space. This coincidence is attributed to the fact that the Bose and Fermi pairs emitted by a mirror have the same spins 1 and 0 as do the photons and scalar quanta emitted by charges. It is shown that the propagation of virtual pairs in 1+1 space can be described by the causal Green's function \Delta_f(z,\mu) of the wave equation for 3+1 space. This is because the pairs can have any positive mass and their propagation function is represented by an integral of the causal propagation function of a massive particle in 1+1 space over mass which coincides with \Delta_f(z,\mu). In this integral the lower limit \mu is chosen small, but nonzero, to eliminate the infrared divergence. It is shown that the real and imaginary parts of the action change are related by dispersion relations, in which a mass parameter serves as the dispersion variable. They are a consequence of the same relations for \Delta_f(z,\mu). Therefore, the appearance of the real part of the action change is a direct consequence of the causality, according to which real part of \Delta_f(z,\mu) is nonzero only for timelike and zero intervals.Comment: 23 pages, Latex, revte

Alignment in Gamma-Hadron Families of Cosmic Rays

Alignment of main fluxes of energy in a target plane is found in families of cosmic ray particles detected in deep lead X-ray chambers. The fraction of events with alignment is unexpectedly large for families with high energy and large number of hadrons. This can be considered as evidence for the existence of coplanar scattering of secondary particles in interaction of particles with superhigh energy, $E_0 > 10^{16}$ eV. Data analysis suggests that production of most aligned groups occurs low above the chamber and is characterized by a coplanar scattering and quasiscaling spectrum of secondaries in the fragmentation region. The most elaborated hypothesis for explanation of alignment is related to the quark-gluon string rupture. However, the problem of theoretical interpretation of our results still remains open.Comment: 15 pages, 2 tables, 6 figures (not included), Stanford University preprint SU-ITP-94-2

Gluonic phases, vector condensates, and exotic hadrons in dense QCD

We study the dynamics in phases with vector condensates of gluons (gluonic phases) in dense two-flavor quark matter. These phases yield an example of dynamics in which the Higgs mechanism is provided by condensates of gauge (or gauge plus scalar) fields. Because vacuum expectation values of spatial components of vector fields break the rotational symmetry, it is naturally to have a spontaneous breakdown both of external and internal symmetries in this case. In particular, by using the Ginzburg-Landau approach, we establish the existence of a gluonic phase with both the rotational symmetry and the electromagnetic U(1) being spontaneously broken. In other words, this phase describes an anisotropic medium in which the color and electric superconductivities coexist. It is shown that this phase corresponds to a minimum of the Ginzburg-Landau potential and, unlike the two-flavor superconducting (2SC) phase, it does not suffer from the chromomagnetic instability. The dual (confinement) description of its dynamics is developed and it is shown that there are light exotic vector hadrons in the spectrum, some of which condense. Because most of the initial symmetries in this system are spontaneously broken, its dynamics is very rich.Comment: 33 pages, RevTeX; v.2: Published PRD versio