Potential of quasielastic meson knockout from a nucleon by high-energy electrons and pions for studying the structure of exotic excited states of a final-state baryon

Journal Article · Sat Mar 15 00:00:00 EDT 2008 · Physics of Atomic Nuclei

DOI:https://doi.org/10.1007/S11450-008-3013-4· OSTI ID:21077523

Fedorov, D K ^[1]; Neudatchin, V G; Sviridova, L L; Smirnov, Yu F ^[2]

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1. Ekogorod Ecological Foundation for the Development of Urban Environment (Russian Federation)
2. Moscow State University, Institute of Nuclear Physics (Russian Federation)

The possibility of studying q{sup 4}q-bar exotic baryon states by means of N(e, e'M)B reactions proceeding via an extremely simple mechanism and involving the quasielastic knockout of various mesons from a nucleon by electrons of energy in the few-GeV region is considered as a development of the previous investigations of our group. A quark microscopic formalism based on the cluster model of q{sup 4}q-bar states, which makes it possible to determine momentum distributions of mesons in various channels of B {sup {yields}} N + M virtual decays (in principle, these distributions can be compared with experimental data), is expounded by considering the example of the pentaquark (B {theta}{sup +}). The decay widths of the q{sup 4}q-bar baryon states being discussed are governed by the degree of separation of quark clusters (this is a parameter of the model used). The electroproduction cross sections prove to be small because of kinematical constraints requiring that physically admissible values of the momentum -parallel k-parallel of the virtual meson M lie in the region where relevant amplitudes are suppressed substantially by form factors in pentaquark vertices. In particular, N (e, e'{pi}{sup {+-}})B reactions involving pion knockout furnish direct information about nonstrange components of baryon B; however, the expected cross sections for such reactions are an order of magnitude smaller than their counterparts for analogous reactions leading to the production of a pentaquark {theta}{sup +}. Because of the smallness of the electroproduction cross sections, it is reasonable to consider the production of a pentaquark and other q{sup 4}q-bar exotic states in reactions characterized by quasielastic kinematics and initiated by pions of energy in the range between about 1 and 5 GeV and in similar stripping and pickup nuclear reactions.

• OSTI ID: 21077523
• Journal Information: Physics of Atomic Nuclei, Vol. 71, Issue 3; Other Information: DOI: 10.1007/s11450-008-3013-4; Copyright (c) 2008 Pleiades Publishing, Ltd; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-7788
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
AMPLITUDES
BARYONS
CLUSTER MODEL
CROSS SECTIONS
DISTRIBUTION
ELECTRON-NUCLEON INTERACTIONS
ELECTRONS
ELECTROPRODUCTION
EXCITED STATES
FORM FACTORS
GEV RANGE 01-10
KNOCK-OUT REACTIONS
NUCLEAR REACTIONS
NUCLEONS
PION-NUCLEON INTERACTIONS
PIONS
POTENTIALS
QUARKS
STRIPPING