18,290 research outputs found
Radiation Emission by Electrons Channeling in Bent Silicon Crystals
Results of numerical simulations of electron channeling and emission spectra
are reported for straight and uniformly bent silicon crystal. The projectile
trajectories are computed using the newly developed module [1] of the MBN
Explorer package [2,3]. The electron channeling along Si(110) crystallographic
planes is studied for the projectile energy 855 MeV.Comment: 9 pages, 7 figures; submitted to European Physical Journal D. arXiv
admin note: text overlap with arXiv:1307.678
Dyson-Schwinger Equation Approach to the QCD Deconfinement Transition and J/Psi Dissociation
We consider an extension of the finite-temperature Dyson-Schwinger equation
(DSE) approach to heavy mesons and quarkonia and apply it to calculate the
cross section for the J/Psi breakup reaction J/Psi + pi --> D + D. We study the
effects of chiral symmetry restoration in the light quark sector on this
process and obtain a critical enhancement of the reaction rate at the chiral/
deconfinement transition. Implications for the kinetics of charmonium
production in ultrarelativistic heavy-ion collisions are discussed with
particular emphasis on the recently observed anomalous J/Psi suppression as a
possible signal for quark matter formation.Comment: 10 pages, 6 figures, sprocl.sty, to appear in: "Progress in
Nonequilibrium Green's functions", M. Bonitz (Ed.), World Scientific,
Singapore, 200
The ground state of the Lithium atom in strong magnetic fields
The ground and some excited states of the Li atom in external uniform
magnetic fields are calculated by means of our 2D mesh Hartree-Fock method for
field strengths ranging from zero up to 2.35 10^8 T. With increasing field
strength the ground state undergoes two transitions involving three different
electronic configurations: for weak fields the ground state configuration
arises from the field-free 1s^22s configuration, for intermediate fields from
the 1s^22p_{-1} configuration and in high fields the 1s2p_{-1}3d_{-2}
electronic configuration is responsible for the properties of the atom. The
transition field strengths are determined. Calculations on the ground state of
the Li+ ion allow us to describe the field-dependent ionization energy of the
Li atom. Some general arguments on the ground states of multi-electron atoms in
strong magnetic fields are provided.Comment: 11 pages, 6 figures, submitted to Physical Review
Semiclassical dynamics of domain walls in the one-dimensional Ising ferromagnet in a transverse field
We investigate analytically and numerically the dynamics of domain walls in a
spin chain with ferromagnetic Ising interaction and subject to an external
magnetic field perpendicular to the easy magnetization axis (transverse field
Ising model). The analytical results obtained within the continuum
approximation and numerical simulations performed for discrete classical model
are used to analyze the quantum properties of domain walls using the
semiclassical approximation. We show that the domain wall spectrum shows a band
structure consisting of 2 non-intersecting zones.Comment: 15 pages, 9 figure
On the polarization properties of the charmed baryon Lambda^+_c in the Lambda^+_c -> p + K^- + pi^+ + pi^0 decay
The polarization properties of the charmed Lambda^+_c baryon are investigated
in weak non-leptonic four-body Lambda^+_c -> p + K^- + pi^+ + pi^0 decay. The
probability of this decay and the angular distribution of the probability are
calculated in the effective quark model with chiral U(3)XU(3) symmetry
incorporating Heavy Quark Effective theory (HQET) and the extended
Nambu-Jona-Lasinio model with a linear realization of chiral U(3)XU(3)
symmetry. The theoretical value of the probability of the decay Lambda^+_c -> p
+ K^- + pi^+ + pi^0 relative to the probability of the decay Lambda^+_c -> p +
K^- + pi^+ does not contain free parameters and fits well experimental data.
The application of the obtained results to the analysis of the polarization of
the Lambda^+_c produced in the processes of photo and hadroproduction is
discussed.Comment: 10 pages, no figures, Late
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