32 research outputs found
Searching for Color Coherent Effects at Intermediate via Double Scattering Processes
We propose that measuring the dependence of the number of final-state
interactions of the recoil protons in quasi-elastic electron scattering from
light nuclei is a new method to investigate Color Coherent effects at {\bf
intermediate} values of ({ few }). This is instead of
measuring events without final-state interactions. Our calculations indicate
that such measurements could reveal significant color transparency effects for
the highest of the energies initially available at CEBAF. Measurements that
detect more than one hadron in the final state, which require the use of large
acceptance () detectors, are required.Comment: 19 pages in RevTex, 5 postscript figures available from
[email protected]
New experimental data for the decays and from SND detector
The processes and have been
studied with SND detector at VEPP-2M collider in the vicinity of
resonance. The branching ratios and were obtained.Comment: 5 pages, 4 figures, talk given at 8th International Conference on
Hadron Spectroscopy (HADRON 99), Beijing, China, 24-28 Aug 199
and couplings in QCD
We calculate the and couplings using QCD sum rules on the
light-cone. In this approach, the large-distance dynamics is incorporated in a
set of pion wave functions. We take into account two-particle and
three-particle wave functions of twist 2, 3 and 4. The resulting values of the
coupling constants are and .
From this we predict the partial width \Gamma (D^{*+} \ra D^0 \pi^+ )=32 \pm
5~ keV . We also discuss the soft-pion limit of the sum rules which is
equivalent to the external axial field approach employed in earlier
calculations. Furthermore, using and the pole
dominance model for the B \ra \pi and D\ra \pi semileptonic form factors
is compared with the direct calculation of these form factors in the same
framework of light-cone sum rules.Comment: 27 pages (LATEX) +3 figures enclosed as .uu file MPI-PhT/94-62 ,
CEBAF-TH-94-22, LMU 15/9
Study of KS KL Coupled Decays and KL -Be Interactions with the CMD-2 Detector at VEPP-2M Collider
The integrated luminosity about 4000 inverse nanobarn of around phi meson
mass ( 5 millions of phi mesons) has been collected with the CMD-2 detector at
the VEPP-2M collider. A latest analysis of the KS KL coupled decays based on 30
% of available data is presented in this paper.
The KS KL pairs from phi meson decays were reconstructed in the drift chamber
when both kaons decayed into two charged particles. From a sample of 1423
coupled decays a selection of candidates to the CP violating KL into pi+ pi-
decay was performed. CP violating decays were not identified because of the
domination of events with a KL regenerating at the Be beam pipe into KS and a
background from KL semileptonic decays.
The regeneration cross section of 110 MeV/c KL mesons was found to be 53 +-
17 mb in agreement with theoretical expectations. The angular distribution of
KS mesons after regeneration and the total cross section of KL for Be have been
measured.Comment: 14 pages, 8 figure
Repulsive Casimir-Polder forces from cosmic strings
We investigate the Casimir-Polder force acting on a polarizable microparticle
in the geometry of a straight cosmic string. In order to develop this analysis
we evaluate the electromagnetic field Green tensor on the imaginary frequency
axis. The expression for the Casimir-Polder force is derived in the general
case of anisotropic polarizability. In dependence of the eigenvalues for the
polarizability tensor and of the orientation of its principal axes, the
Casimir-Polder force can be either repulsive or attractive. Moreover, there are
situations where the force changes the sign with separation. We show that for
an isotropic polarizability tensor the force is always repulsive. At large
separations between the microparticle and the string, the force varies
inversely as the fifth power of the distance. In the non-retarded regime,
corresponding to separations smaller than the relevant transition wavelengths,
the force decays as the inverse fourth power of the distance. In the case of
anisotropic polarizability, the dependence of the Casimir-Polder potential on
the orientation of the polarizability tensor principal axes also leads to the
moment of force acting on the particle.Comment: 16 pages, 2 figure
Search for rare Phi decays in pi+ pi_ gamma final state
A search for phi radiative decays has been performed using a data sample of
about 2.0 million phi decays collected by the CMD-2 detector at VEPP-2M
collider in Novosibirsk. From the selected e+ e- -> pi+ pi- gamma events the
following results were obtained: B(phi -> f0(980) gamma) < 1x10-4 for
destructive and B(phi -> f0(980) gamma) < 7x10-4 for constructive interference
with the Bremsstrahlung process respectively, B(phi -> gamma -> pi+ pi- gamma)
20 MeV, B(phi -> rho gamma) < 7x10-4. From the
selected e+ e- -> mu+ mu- gamma events B(phi -> mu+ mu- gamma) =
(2.3+-1.0)x10-5 has been obtained for E of gamma> 20 MeV. The upper limit on
the P,CP-violating decay eta -> pi+ pi- has also been placed: B(eta -> pi+ pi-)
< 9x10-4 . All upper limits are at 90 % C.L.Comment: 18 pages, 7 figure
Experimental Research Results of the Slot Seal Constructed as Hydrodiode for the Hybrid Power Piston Volumetric Machine
AbstractThe aim is to present the experimental studies results of the annular piston slot seal constructed in the hydrodiode form. This seal was considered in relation to the piston hybrid machine of volumetric operation. The paper describes the experimental test-bench, a node of load-registration and a hydrodiode node. The progress of the pilot studies has been described. Also some experimental results are presented in the paper. They allow to compare the numerical and field experiments findings and to conduct the slot seal initial geometry optimization, to make recommendations for the further design and construction of hybrid power piston volumetric machines