2,214 research outputs found
Bose-Einstein correlations at LEP and Tevatron energies
Using the Bose-Einstein correlations (BEC) implemented in PYTHIA we
investigated a possibility of the CDF experiment at the Tevatron to see the
two-particle correlations in the final state of interactions. The approach
based on quantum field theory at finite temperature was applied to the ALEPH
data at LEP, and the BEC important parameters were retrieved.Comment: 5 pages, 4 figures, 1 table. Based on the talk gived at The 6th
international workshop on very high multiplicity physics, JINR Dubna, 16-17
april 2005. In Table 1. the sign of error adde
Cooper pairing of electrons and holes in graphene bilayer: Correlation effects
Cooper pairing of spatially separated electrons and holes in graphene bilayer
is studied beyond the mean-field approximation. Suppression of the screening at
large distances, caused by appearance of the gap, is considered
self-consistently. A mutual positive feedback between appearance of the gap and
enlargement of the interaction leads to a sharp transition to correlated state
with greatly increased gap above some critical value of the coupling strength.
At coupling strength below the critical, this correlation effect increases the
gap approximately by a factor of two. The maximal coupling strength achievable
in experiments is close to the critical value. This indicated importance of
correlation effects in closely-spaced graphene bilayers at weak substrate
dielectric screening. Another effect beyond mean-field approximation considered
is an influence of vertex corrections on the pairing, which is shown to be very
weak.Comment: 6 pages, 5 figures; some references were adde
Enhancement of the electric dipole moment of the electron in BaF molecule
We report results of ab initio calculation of the spin-rotational Hamiltonian
parameters including P- and P,T-odd terms for the BaF molecule. The ground
state wave function of BaF molecule is found with the help of the Relativistic
Effective Core Potential method followed by the restoration of molecular
four-component spinors in the core region of barium in the framework of a
non-variational procedure. Core polarization effects are included with the help
of the atomic Many Body Perturbation Theory for Barium atom. For the hyperfine
constants the accuracy of this method is about 5-10%.Comment: 8 pages, REVTEX, report at II International Symposium on Symmetries
in Subatomic Physics, Seattle 199
Antineutrino-Deuteron Experiment at Krasnoyrsk
This report is represented the results of some experiments, which carried out
at the neutrino underground laboratory of Kranoyarsk nuclear plant.Comment: 8 pages, 3 figure
The structure of heat-resisting alloy modified by thermal treatment and alloyed by rhenium and lanthanum
The paper presents the scanning and transmission electron microscope investigations of the structure, phase composition, and morphology of heat-resisting alloy modified by thermal treatment and additionally alloyed by rhenium and lanthanum. Rhenium alloy is obtained by the directional crystallization technique. The structural investigations are carried out for three alloy states, i.e. 1) original (after the directional crystallization); 2) 1150°С annealing during 1 h and 1100°С annealing during 480 h; 3) 1150°С annealing during 1 h and 1100°С annealing during 1430 h. It is shown that fcc-based [gamma]- and [gamma]'-phases are primary in all states of the alloy. [gamma]'-phase has L12 structure, while [gamma]-phase is a disordered phase. Rhenium and lanthanum are phase-forming elements. Investigations show that high-temperature annealing modifies the structural and phase conditions of the heat-resisting alloy
Spin noise of a halide perovskite
We report on first observation of spin noise in a strongly birefringent
semiconductor -- halide perovskite single crystal MAPbI. The observed spin
noise resonance is ascribed to free holes with a record spin dephasing time of
4 ns. The spin dynamics is found to be affected by the residual light
absorption of the crystal providing renormalization of the Larmor frequency.
Extended spin noise spectroscopy with rotating magnetic field allowed us not
only to evaluate the -factor anisotropy, but also to distinguish two
different spin subsystems tentatively associated to twinning of the crystal.Comment: 14 pages, 11 figure
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