26 research outputs found
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
Electron-electron interaction at decreasing
The contribution of the electron-electron interaction to conductivity is
analyzed step by step in gated GaAs/InGaAs/GaAs heterostructures with different
starting disorder. We demonstrate that the diffusion theory works down to , where is the Fermi quasimomentum, is the mean free
paths. It is shown that the e-e interaction gives smaller contribution to the
conductivity than the interference independent of the starting disorder and its
role rapidly decreases with decrease.Comment: 5 pages, 6 figure
Virtual-pion and two-photon production in pp scattering
Two-photon production in pp scattering is proposed as a means of studying
virtual-pion emission. Such a process is complementary to real-pion emission in
pp scattering. The virtual-pion signal is embedded in a background of
double-photon bremsstrahlung. We have developed a model to describe this
background process and show that in certain parts of phase space the
virtual-pion signal gives significant contribution. In addition, through
interference with the two-photon bremsstrahlung background, one can determine
the relative phase of the virtual-pion process
Low-lying S-wave and P-wave Dibaryons in a Nodal Structure Analysis
The dibaryon states as six-quark clusters of exotic QCD states are
investigated in this paper. With the inherent nodal surface structure analysis,
the wave functions of the six-quark clusters (in another word, the dibaryons)
are classified. The contribution of the hidden color channels are discussed.
The quantum numbers of the low-lying dibaryon states are obtained. The States
, ,
, and the
hidden color channel states with the same quantum numbers are proposed to be
the candidates of dibaryons, which may be observed in experiments.Comment: 29 pages, 2 figure
Non-Abelian dynamics and heavy multiquarks, Steiner-tree confinement in hadron spectroscopy
A brief review is first presented of attempts to predict stable multiquark
states within current models of hadron spectroscopy. Then a model combining
flip-flop and connected Steiner trees is introduced and shown to lead to stable
multiquarks, in particular for some configurations involving several heavy
quarks and bearing exotic quantum numbers.Comment: 8 pages, 5 figures, Invited talk at the 21st European Conference on
Few-Body Problems in Physics, Salamanca, Spain, August 29th--September 3rd,
2010, to appear in the Proceedings, ed.~A.~Valcarce et al., to appear in
Few-Body Syste
Transverse Negative Magnetoresistance of Two-dimensional Structures in the Presence of a Strong In-plane Magnetic Field: Weak Localization as a Probe of Interface Roughness
The interference induced transverse negative magnetoresistance of GaAs/InxGa1-xAs/GaAs quantum well heterostructures has been studied in the presence of strong in-plane magnetic field. It is shown that the effect of in-plane magnetic field is determined by the interface roughness and strongly depends on the relationship between mean free path, phase breaking length, and roughness correlation length. Analysis of the experimental results allows us to estimate parameters of short- and long-range correlated roughness which have been found in a good agreement with atomic force microscopy data obtained for just the same samples.This work was supported in part by the RFBR through Grant Nos. 01-02-16441, 03-02-16150, 03-02-06025, and 04-02-16626, the CRDF through Grant Nos. EK-005-X1 and Y1-P-05-11, and the Russian Program Physics of Solid State Nanostructures