119 research outputs found
SPIN-DEPENDENT OBSERVABLES AND THE D 2 PARAMETER IN BREAKUP OF DEUTERON AND 3 He
We analyze the momentum distributions of constituents in 3 He, as well as the spin-dependent observables for ( 3 He, d), ( 3 He, p), and (d, p) breakup reactions. Special attention is paid to the region of small relative momenta of the helium-3 and deuteron constituents, where a single parameter, D 2 , has determining role for the spin-dependent observables. We extract also this parameter for the deuteron, basing on the existing data for the tensor analyzing power of this (d, p) breakup. The investigation has been performed at the Veksler and Baldin Laboratory of High Energy Physics, JINR
Isoscalar short-range current in the deuteron induced by an intermediate dibaryon
A new model for short-range isoscalar currents in the deuteron and in the NN
system is developed; it is based on the generation of an intermediate dibaryon
which is the basic ingredient for the medium- and short-range NN interaction
which was proposed recently by the present authors.This new current model can
very well describe the experimental data for the three basic deuteron
observables of isoscalar magnetic type, viz. the magnetic moment, the circular
polarization of the photon in the process at thermal neutron
energies and the structure function B up to Q=60 fm.Comment: LaTex, 22 pages with 8 figure
Formation of 24Mg* in the Splitting of 28Si Nuclei by 1-GeV Protons
The 28Si(p, p' gamma)24Mg reaction has been studied at the ITEP accelerator
by the hadron-gamma coincidence method for a proton energy of 1 GeV. Two
reaction products are detected: a 1368.6-keV gamma-ray photon accompanying the
transition of the 24Mg* nucleus from the first excited state to the ground
state and a proton p' whose momentum is measured in a magnetic spectrometer.
The measured distribution in the energy lost by the proton in interaction is
attributed to five processes: the direct knockout of a nuclear alpha cluster,
the knockout of four nucleons with a total charge number of 2, the formation of
the DeltaSi isobaric nucleus, the formation of the Delta isobar in the
interaction of the incident proton with a nuclear nucleon, and the production
of a pi meson, which is at rest in the nuclear reference frame. The last
process likely corresponds to the reaction of the formation of a deeply bound
pion state in the 28P nucleus. Such states were previously observed only on
heavy nuclei. The cross sections for the listed processes have been estimated.Comment: 14 pages, 3 figures submitted to JETP Letter
Study of isobar electroproduction at VEPP-2M collider
Results from the Spherical Nonmagnetic Detector (SND) on
isobar electroproduction in the collisions of beam electrons (positrons) and
residual gas nuclei in the VEPP-2M collider are presented. On the
basis of the obtained data the expected counting rate of this process in future
high luminosity colliders (~-, -- and -factories)
was estimated.Comment: 7 pages LATEX and 3 figure
Mechanism of Pion Production in p Scattering at 1 GeV/nucleon
The one-pion and two-pion production in the p(alpha, alpha prime)X reaction
at an energy of E{alpha} = 4.2 GeV has been studied by simultaneous
registration of the scattered alpha particles and the secondary pion or proton.
The obtained results demonstrate that the inelastic alpha-particle scattering
on the proton at the energy of the experiment proceeds either through
excitation and decay of Delta resonance in the projectile or through excitation
in the target proton of the Roper resonance, which decays mainly on a nucleon
and a pion or a nucleon and a sigma meson - system of two pions in the isospin
I = 0, S-wave.Comment: 16 pages, 10 figures. Submitted to Proceedings of the XX
International Baldin Seminar on High - Energy Physics Problems, Dubna,
October 4 - 9, 201
Projectile and target-Roper excitation in the p (d, d')X reaction
In this paper we compare a model that contains the mechanisms of
excitation in the projectile and Roper excitation in the target with
experimental data from two (d, d') experiments on a proton target. The
agreement of the theory with the experiment is fair for the data taken at T_d =
2.3 GeV. The excitation in the projectile is predicted close to the
observed energy with the correct width. The theory, however, underpredicts by
about 40% the cross sections measured at T_d = 1.6 GeV at angles where the
cross section has fallen by about two orders of magnitude. The analysis done
here allows to extract an approximate strength for the excitation of the Roper
[N^*(1440)] excitation and a qualitative agreement with the theoretical
predictions is also found.Comment: 8 ps figure
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