47 research outputs found
Study of two-photon production process in proton-proton collisions at 216 MeV
The energy spectrum for high energy -rays ( MeV)
from the process emitted at in the laboratory
frame has been measured at 216 MeV. The resulting photon energy spectrum
extracted from coincidence events consists of a narrow peak
(5.3) at a photon energy of about 24 MeV and a relatively broad peak
(3.5) in the energy range of (50 - 70) MeV. This behavior of the photon
energy spectrum is interpreted as a signature of the exotic dibaryon resonance
with a mass of about 1956 MeV which is assumed to be formed in the
radiative process followed by its electromagnetic
decay via the mode. The experimental spectrum is
compared with those obtained by means of Monte Carlo simulations.Comment: 4 pages, LaTex, 1 eps-figure; Talk given at the HADRON 2001,
Protvino, Russia, August 27 - September 1,2001, to be published in the
proceedin
Analysis of negative magnetoresistance. Statistics of closed paths. II. Experiment
It is shown that a new kind of information can be extracted from the Fourier
transform of negative magnetoresistance in 2D semiconductor structures. The
procedure proposed provides the information on the area distribution function
of closed paths and on the area dependence of the average length of closed
paths. Based on this line of attack the method of analysis of the negative
magnetoresistance is suggested. The method has been used to process the
experimental data on negative magnetoresistance in 2D structures with different
relations between the momentum and phase relaxation times. It is demonstrated
this fact leads to distinction in the area dependence of the average length of
closed paths.Comment: 5 pages, 5 figures, to be published in Phys.Rev.
Resonance structure in the {\gamma}{\gamma} and systems in dC interactions
Along with and {\eta} mesons, a resonance structure in the invariant
mass spectrum of two photons at M{\gamma}{\gamma} = 360 \pm 7 \pm 9 MeV is
observed in the reaction d + C \rightarrow {\gamma} + {\gamma} + X at momentum
2.75 GeV/c per nucleon. Estimates of its width and production cross section are
{\Gamma} = 64 \pm 18 MeV and = 98 \pm 24 {\mu}b,
respectively. The collected statistics amount to 2339 \pm 340 events of 1.5
\cdot 10^6 triggered interactions of a total number ~ 10^12 of dC-interactions.
The results on observation of the resonance in the invariant mass spectra of
two mesons are presented: the data obtained in the d + C \rightarrow
{\gamma} + {\gamma} reaction is confirmed by the d + C \rightarrow +
reaction: = 359.2 \pm 1.9 MeV, {\Gamma} = 48.9 \pm 4.9
MeV; the ratio of Br(R\rightarrow{\gamma}{\gamma}) /
Br(R\rightarrow) = (1.8 {\div} 3.7)\cdot10^-3.Comment: 10 pages, 11 figure
Analysis of Negative Magnetoresistance: Statistics of Closed Paths. II. Experiment
It is shown that a new kind of information can be extracted from the Fourier transform of negative magnetoresistance in two-dimensional (2D) semiconductor structures. The procedure proposed provides the information on the area distribution function of closed paths and on the area dependence of the average length of closed paths. Based on this line of attack the method of analysis of the negative magnetoresistance is suggested. The method has been used to process the experimental data on negative magnetoresistance in 2D structures with different relations between the momentum and phase relaxation times. It is demonstrated this fact leads to distinction in the area dependence of the average length of closed paths. © 2000 The American Physical Society.This work was supported in part by the RFBR through Grants Nos. 97-02-16168, 98-02-16624 and 98-02-17286, the Russian Program Physics of Solid State Nanostructures through Grant No. 97-1091, and the Program University of Russia through Grant No. 420