Direct Photons in Ion Collisions at FAIR Energies

Estimations of prompt photon production at FAIR (Facility for Antiproton and Ion Research) energies using the extrapolation of existing data are presented. About $10^{-4}$ prompt $\gamma$ with $p_{t}>$2 GeV/c per Au+Au central event at 25 AGeV are expected. With the planed beam intensity $10^{9}/s$, 1% interaction rate and 10% centrality, at CBM (Compressed Baryonic Matter) experiment one can expect prompt $\gamma$ rate ~100/s. Predictions for direct photons by some generators (PYTHIA, UrQMD, RQMD, HSD, HIJING) are analyzed. One of the main sources of direct photons (due to meson scatterings $\pi\rho\to\pi\gamma, \pi\pi\to\rho\gamma$) is not implemented in the heavy-ion generators. Corresponding cross-sections for this source have been prepared for implementation into the HSD code. Main experimental methods to study direct photons (subtraction method, momentum correlations method and internal conversion method) are shortly reviewed. High intensity beam, good tracking and good $e^{\pm}$ particle identification of the CBM detector favor to measure direct photons by all the methods.Comment: 7 pages,5 figures,Talk at Baldin ISHEPP XVIII, Dubna, 25 - 30 September 200

Surface-to-volume ratio with oscillating gradients

Restrictions to diffusion result in the dispersion of the bulk diffusion coefficient. We derive the exact universal high-frequency behavior of the diffusion coefficient in terms of the surface-to-volume ratio of the restrictions. This frequency dependence can be applied to quantify structure of complex samples with NMR using oscillating field gradients and static-gradient CPMG. We also demonstrate the inter-relations between different equivalent diffusion metrics, and describe how to calculate the effect of restrictions for arbitrary gradient waveforms.Comment: 6 pages, 1 figur

Natural scale of cosmological constant in seesaw mechanism with broken SUSY

The cosmological constant is inherently determined by the scale of breaking down supersymmetry in the mechanism of seesaw fluctuations of two vacuum-states.Comment: 4 pages, revtex4 class, reference adde

The slowly passage through the resonances and wave packets with the different carriers

Solution of the nonlinear Klein-Gordon equation perturbed by small external force is investigated. The perturbation is represented by finite collections of harmonics. The frequencies of the perturbation vary slowly and pass through the resonant values consecutively. The resonances lead to the sequence of the wave packets with the different fast oscillated carriers. Full asymptotic description of this process is presented.Comment: 24 pages, LaTe

Scattering of solitons on resonance

We investigate a propagation of solitons for nonlinear Schrodinger equation under small driving force. The driving force passes the resonance. The process of scattering on the resonance leads to changing of number of solitons. After the resonance the number of solitons depends on the amplitude of the driving force.Comment: LaTeX, 10 page

Properties of potential modelling three benchmarks: the cosmological constant, inflation and three generations

We argue for a model of low-energy correction to the inflationary potential as caused by the gauge-mediated breaking down the supersymmetry at the scale of \mu_\textsc{x}\sim 10^4 GeV, that provides us with the seesaw mechanism of thin domain wall fluctuations in the flat vacuum. The fluctuations are responsible for the vacuum with the cosmological constant at the scale of $\mu_\Lambda\sim 10^{-2}$ eV suppressed by the Planckian mass $m_\mathtt{Pl}$ via \mu_\Lambda\sim\mu_\textsc{x}^2/m_\mathtt{Pl}. The appropriate vacuum state is occupied after the inflation with quartic coupling constant \lambda\sim\mu_\textsc{x}/m_\mathtt{Pl}\sim 10^{-14} inherently related with the bare mass scale of \widetilde m\sim\sqrt{\mu_\textsc{x}m_\mathtt{Pl}}\sim 10^{12} GeV determining the thickness of domain walls $\delta r\sim1/\widetilde m$. Such the parameters of potential are still marginally consistent with the observed inhomogeneity of matter density in the Universe. The inflationary evolution suggests the vacuum structure compatible with three fermionic generations of matter as well as with observed hierarchies of masses and mixing in the Standard Model.Comment: 12 pages, 1 figure, revtex4 class, references adde

Renormalization group analysis of cosmological constraint on the mass of Higgs scalar

The Higgs boson of Standard Model, minimally coupled to the gravitation, is not able to produce the inflation of early Universe if its mass exceeds the threshold value, which is equal to m_H^{min} = 142 GeV in the tree approximation for the scalar potential. Two-loop corrections modify the estimate as m_H^{min} = 150 \pm 3 GeV, so that higher-order corrections of perturbation theory are completely under control, though they are numerically important in respect of experimental searches.Comment: 6 page

The capture into parametric autoresonance

In this work we show that the capture into parametric resonance may be explained as the pitchfork bifurcation in the primary parametric resonance equation. We prove that the solution close to the moment of the capture is described by the Painleve-2 equation. We obtain the connection formulas for the asymptotic solution of the primary parametric resonance equation before and after the capture using the matching of the asymptotic expansions.Comment: LaTeX, 21 pages, 3 figure

The surface density of holographic entropy

On the basis of postulates for the holographic description of gravity and the introduction of entropic force, for static sources we derive the universal law: the entropy of a holographic screen is equal to quarter of its area in the Planck system of units.Comment: 6 page

Asymptotic description of nonlinear resonance

We study a hard regime of stimulation of two-frequency oscillations in the main resonance equation with a fast oscillating external force: \ve i \psi' + |\psi|^2\psi = \exp\big(it^2/ (2\ve)\big), 0<\ve\ll1. This phenomenon is caused by resonance between an eigenmode and the external force. The asymptotic solution before, inside and after the resonance layer is studied in detail and matched.Comment: LaTeX, 48 pages, two figure