Quasifree {pi}{sup 0} and {pi}{sup -} Electroproduction on {sup 4}He in the {delta}-Resonance Region

Journal Article · Fri Oct 21 04:00:00 EDT 2005 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.95.172501· OSTI ID:20699466

Steenbakkers, M F.M.; Blok, H P; Botto, T; Heimberg, P; Hesselink, W H.A.; Ketel, T J; Starink, R ^[1]; Batenburg, M.F. van; Bauer, Th S; Groep, D L; Jans, E; Lapikas, L; Lange, D J.J. de; Passchier, I; Vries, H de ^[2]; Dodge, G E; Jun, Y; Todor, L ^[3]; Higinbotham, D W; Norum, B E ^[4]

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1. Department of Physics and Astronomy, Free University de Boelelaan, 1081 HV Amsterdam (Netherlands)
2. NIKHEF, P.O. Box 41882, 1009 DB Amsterdam (Netherlands)
3. Department of Physics, Old Dominion University, Norfolk, Virginia 23529 (United States)
4. University of Virginia, Charlotteville, Virginia 22901 (United States)

The reactions {sup 4}He(e,e{sup '}p{sup 3}He){pi}{sup -} and {sup 4}He(e,e{sup '}p{sup 3}He){pi}{sup 0} were studied simultaneously, and for the first time, in a large kinematical domain including the {delta}-resonance region. This was achieved by detecting the recoiling {sup 3}He and {sup 3}H nuclei instead of the emitted pions. The dependences of the cross section on the recoil momentum p{sub rec}, the invariant mass W{sub {pi}}{sub N}, and the direction {theta}{sub {pi},q{sup '}} and {phi}{sub {pi},q{sup '}} of the produced pion, are globally well described by the results of (quasifree) distorted-wave impulse approximation calculations. However, in the {delta}-resonance region there are clear discrepancies, which point to medium modifications of the {delta} in {sup 4}He.

• OSTI ID: 20699466
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 17 Vol. 95; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
CROSS SECTIONS
DISTORTED WAVE THEORY
DWBA
ELECTRON REACTIONS
ELECTROPRODUCTION
EMISSION
HELIUM 3
HELIUM 4
HELIUM 4 TARGET
IMPULSE APPROXIMATION
MASS
PIONS MINUS
PIONS NEUTRAL
RECOILS
RESONANCE
TRITIUM