Emission of High-Energy Alpha Particles in the Interaction of $${}^{48}$$ Ca Nuclei with Tantalum,Gold, and Uranium Nuclei at 280 MeV

Physics of Atomic Nuclei - The energy spectra of alpha particles from reactions induced by 280-MeV $${}^{48}$$ Ca beams incident to $${}^{181}$$ Ta, $${}^{197}$$ Au, and $${}^{238}$$ U targets were...     

Fast Charged Particles in the Interaction of $${}^{{56}}$$ Fe with Be,Ta, and U Nuclei at an Energy of 400 MeV

Physics of Atomic Nuclei - The energy spectra of alpha particles emitted at an angle of 0 $${}^{\circ}$$ in the interaction of 400-MeV $${}^{56}$$ Fe ions with $${}^{238}$$ U, $${}^{181}$$ Ta, and...     

Systematic Approach to Calculate the Total Kinetic Energy Distribution of Actinides for the Photofission Phenomenon

Physics of Atomic Nuclei - The total kinetic energy as a function of fragment mass (TKE/A) was calculated for photofission of $${}^{232}$$ Th, $${}^{234}$$ U, $${}^{238}$$ U, $${}^{240}$$ Pu, and...     

Peculiarity of the $${}^{{12}}$$ C(0 $${{}^{+}}$$ ) and $${}^{{12}}$$ C(2 $${{}^{+}}$$ ) Energy Spectrum in a 3 $$\alpha$$ Model

Physics of Atomic Nuclei - Lowest energy spectrum of the $${}^{12}$$ C nucleus is analyzed in the 3 $$\alpha$$ -cluster model with a deep $$\alpha\alpha$$ potential of Buck, Friedrich and Wheatley...     

Results of the Further Analysis of Data from the Tien Shan Array in the Energy Spectrum of Primary Cosmic Rays in the Energy Range of $${2\times 10^{13}{-}3\times 10^{17}}$$ eV

Physics of Atomic Nuclei - The energy spectrum of primary cosmic rays at energies between 2 $$\times 10^{13}$$ and 3 $$\times 10^{17}$$ eV is presented according to data from the Tien Shan array on...     

On the Mean Value of the Potential and Kinetic Energy of an Electron in a Hydrogenlike Atom

Russian Physics Journal - The mean values of the potential $$ \left\langle \hat{\varPi}\right\rangle $$ and kinetic $$ \left\langle \hat{\mathrm{T}}\right\rangle $$ energy of an electron in a...     

Search for Delayed and Advanced Particles in the Interaction of Ultrahigh-Energy Cosmic Rays with the Earth’s Atmosphere in the Flow of EAS Muons at the MSU EAS Setup

Physics of Atomic Nuclei - The results obtained by studying temporal distributions of particles of energy in excess of 5 GeV in extensive air showers (EAS) of energy above $$10^{15}$$ eV at...     

Observation of Migdal’s Effect in Nuclear Emulsions upon Muon Decay in Mesic Atoms

Physics of Atomic Nuclei - 2520 stops and interactions of $$\mu^{-}$$ mesons were observed in a nuclear emulsion. The energy spectra and angular distribution of Auger electrons accompanying...     

Mechanisms of B Meson Suppression in Ultrarelativistic Heavy Ion Collisions

Journal of Experimental and Theoretical Physics - Different mechanisms of B meson suppression in lead ion collisions at an energy of the Large Hadron Collider $$\sqrt {{{s}_{{NN}}}} $$ = 5.02 TeV...     

Cubic Interaction and Triaxiality in $$\boldsymbol{{}^{236{-}246}}$$ Pu Nuclei

Physics of Atomic Nuclei - In the present study, we investigate even–even $${}^{236{-}246}$$ Pu isotopes with triaxial interacting boson model. Calculations for the energy levels and $$E$$ 2...     

Data on Neutron–Neutron Scattering Length from the Reaction $$\boldsymbol{n+^{2}\textrm{H}\to n+n+p}$$ at $$\boldsymbol{E_{n}=60}$$ MeV

Physics of Atomic Nuclei - The $${}^{1}S_{0}$$ neutron–neutron ( $$nn$$ ) scattering length was measured in the neutron–deuteron ( $$nd$$ ) breakup reaction at an energy of 60 MeV. The...     

Searches for New Physics in the Dilepton Channel with the CMS Detector at the Large Hadron Collider

Physics of Atomic Nuclei - Results of searches for signals from new physics beyond the Standard Model in proton–proton collisions at the c.m. energy of $$\sqrt{s}=13$$ TeV are surveyed....     

Imaging Atmospheric Cherenkov Telescope for the TAIGA Observatory—JINR Participation

Physics of Atomic Nuclei - IACTs are one of the key parts of the TAIGA observatory and designed for study of gamma rays and charged cosmic rays in the energy range of 10 $${}^{13}{-}10^{18}$$ eV....     

Dilatonic Dark Energy Model with Late Time de Sitter Attractor

Based on Weyl-scaled induced gravitational theory, we regard dilaton field in this theory as a candidate of dark energy. We construct a dilatonic dark energy model and its phantom model, that admit late time de Sitter attractor solution. When we take the potential of dilaton field as the form which has been studied in supergravity model and the famous Mexican hat potential , we show mathematically that these attractor solutions correspond to an equation of state ω = −1 and a cosmic density parameter Ω_σ = 1, which are important features for a dark energy model that can meet the current observations.     

Hopf Bifurcations,Drops in the Lid-Driven Square Cavity Flow

The lid-driven square cavity flow is investigated by numerical experiments. It is found that from $ \mathrm{Re} $$=$ $5,000 $ to $ \mathrm{Re} $$=$$ 7,307.75 $ the solution is stationary, but at $ \mathrm{Re}$$=$$7,308 $ the solution is time periodic. So the critical Reynolds number for the first Hopf bifurcation localizes between $ \mathrm{Re} $$=$$ 7,307.75 $ and $ \mathrm{Re} $$=$$ 7,308 $. Time periodical behavior begins smoothly, imperceptibly at the bottom left corner at a tiny tertiary vortex; all other vortices stay still, and then it spreads to the three relevant corners of the square cavity so that all small vortices at all levels move periodically. The primary vortex stays still. At $ \mathrm{Re} $$=$$ 13,393.5 $ the solution is time periodic; the long-term integration carried out past $ t_{\infty} $$=$$ 126,562.5 $ and the fluctuations of the kinetic energy look periodic except slight defects. However, at $ \mathrm{Re} $$=$$ 13,393.75 $ the solution is not time periodic anymore: losing unambiguously, abruptly time periodicity, it becomes chaotic. So the critical Reynolds number for the second Hopf bifurcation localizes between $ \mathrm{Re} $$=$$ 13,393.5 $ and $ \mathrm{Re} $$=$$ 13,393.75 $. At high Reynolds numbers $ \mathrm{Re} $$=$$ 20,000 $ until $ \mathrm{Re} $$=$$ 30,000 $ the solution becomes chaotic. The long-term integration is carried out past the long time $ t_{\infty} $$=$$ 150,000 $, expecting the time asymptotic regime of the flow has been reached. The distinctive feature of the flow is then the appearance of drops: tiny portions of fluid produced by splitting of a secondary vortex, becoming loose and then fading away or being absorbed by another secondary vortex promptly. At $ \mathrm{Re} $$=$$ 30,000 $ another phenomenon arises—the abrupt appearance at the bottom left corner of a tiny secondary vortex, not produced by splitting of a secondary vortex.     

Charge Radii of Tin Isotopes and Their Proton-Density Distributions within the Dispersive Optical Model

Proton single-particle properties of even–even tin isotopes in the mass number range between 100 and 132 were calculated on the basis of the dispersive optical model. The possibility of describing data on the charge radius $$r_{\mathrm{ch}}$$ was studied. A decrease in the rate of growth of $$r_{\mathrm{ch}}$$ with increasing $$N$$ in the region of $$N>76$$ was obtained via increasing the energy interval in the vicinity of $$E_{\mathrm{F}}$$ where the imaginary part of the potential used is close to zero. The predictive power of the dispersive optical model for the density distribution in nuclei far from the beta-stability valley was demonstrated.     

A comparison of b and uds quark jets to gluon jets

Symmetric three-jet events are selected from hadronic Z⁰ decays such that the two lower energy jets are each produced at an angle of about 150° with respect to the highest energy jet. In some cases, a displaced secondary vertex is reconstructed in one of the two lower energy jets, which permits the other lower energy jet to be identified as a gluon jet through anti-tagging. In other cases, the highest energy jet is tagged as a b jet or as a light quark (uds) jet using secondary vertex or track impact parameter and momentum information. Comparing the two lower energy jets of the events with a tag in the highest energy jet to the anti-tagged gluon jets yields a direct comparison of b, uds and gluon jets, which are produced with the same energy of about 24 GeV and under the same conditions. We observe b jets and gluon jets to have similar properties as measured by the angular distribution of particle energy around the jet directions and by the fragmentation functions. In contrast, gluon jets are found to be significantly broader and to have a markedly softer fragmentation function than uds jets. For the k _⊥ jet finder with y _cut=0.02, we find $${«ngle n^{? ch.}»ngle {? gluon}?er «ngle n^{? ch.}»ngle {? b} {? quark}}=1.089pm 0.024 ({? stat.})pm0.024 ({? syst.})$$ $${«ngle n^{? ch.}»ngle {? gluon}?er «ngle n^{? ch.}»ngle {? uds} {? quark}}=1.390pm 0.038 ({? stat.})pm0.032 ({? syst.})$$ as the ratios of the mean charged particle multiplicity in the gluon jets compared to the b and uds jets. Results are also reported using the cone jet finder.     

Measurement of event shape and inclusive distributions at ${sqrt s} = 130$ and 136 GeV

Inclusive charged particle and event shape distributions are measured using 321 hadronic events collected with the DELPHI experiment at LEP at effective centre of mass energies of 130 to 136 GeV. These distributions are presented and compared to data at lower energies, in particular to the precise Z data. Fragmentation models describe the observed changes of the distributions well. The energy dependence of the means of the event shape variables can also be described using second order QCD plus power terms. A method independent of fragmentation model corrections is used to determine α_s from the energy dependence of the mean thrust and heavy jet mass. It is measured to be: $$←pha _s(133 {? GeV})={0.116}pm {0.007}_{exp-0.004theo}^{+0.005}$$ from the high energy data.     

Transition from decelerated to accelerated cosmic expansion in braneworld universes

Braneworld theory provides a natural setting to treat, at a classical level, the cosmological effects of vacuum energy. Non-static extra dimensions can generally lead to a variable vacuum energy, which in turn may explain the present accelerated cosmic expansion. We concentrate our attention in models where the vacuum energy decreases as an inverse power law of the scale factor. These models agree with the observed accelerating universe, while fitting simultaneously the observational data for the density and deceleration parameter. The redshift at which the vacuum energy can start to dominate depends on the mass density of ordinary matter. For _m = 0.3, the transition from decelerated to accelerated cosmic expansion occurs at z _T ≈ 0.48 ± 0.20, which is compatible with SNe data. We set a lower bound on the deceleration parameter today, namely > − 1 + 3 _m /2, i.e., > − 0.55 for _m = 0.3. The future evolution of the universe crucially depends on the time when vacuum starts to dominate over ordinary matter. If it dominates only recently, at an epoch z < 0.64, then the universe is accelerating today and will continue that way forever. If vacuum dominates earlier, at z > 0.64, then the deceleration comes back and the universe recollapses at some point in the distant future. In the first case, quintessence and Cardassian expansion can be formally interpreted as the low energy limit of our model, although they are entirely different in philosophy. In the second case there is no correspondence between these models and ours.     

Laser Cooling and Spectroscopy of Relativistic C^{3+} Beams at the ESR

We report on the first laser cooling of a bunched beam of multiply charged ions performed at the ESR (GSI) at a beam energy of GeV. Moderate bunching provided a force counteracting the decelerating laser force of one counterpropagating laser beam. This versatile type of laser cooling lead to longitudinally space-charge dominated beams with an unprecedented momentum spread of . Concerning the beam energy and charge state of the ion, the experiment depicts an important intermediate step from the established field of laser cooling of ion beams at low energies toward the unique laser cooling scheme proposed for relativistic beams of highly charged heavy ions at SIS 300 (FAIR). Funded by the German BMBF under contract number 06ML183.