Hypernuclear physics with pions. [PWA, DWIA, EIK]

Journal Article · Sat Nov 01 04:00:00 EST 1980 · Phys. Rev., C; (United States)

DOI:https://doi.org/10.1103/PhysRevC.22.2073· OSTI ID:6822866

Dover, C B; Ludeking, L; Walker, G E

We investigate the possibility of producing hypernuclei with energetic pion beams via the (..pi../sup +/, K/sup +/) reaction. Due to the high momentum transfer involved (qapprox. =300 MeV/c), even in the forward direction, the (..pi../sup +/, K/sup +/) reaction preferentially populates high-spin natural parity configurations obtained by coupling a ..lambda.. particle to a neutron hole. We present differential cross section calculations utilizing the plane-wave approximation (PWA), the distorted-wave impulse approximation (DWIA) using fully distorted-waves, and the eikonal approximation (EIK) to approximate distortion effects. The DWIA and EIK results are in agreement, and lead to cross sections typically a factor of 5 --10 lower than the PWA results, due to absorptive effects. Cross sections of 5 --20 ..mu..b/sr at 0/sup 0/ are obtained in the DWIA for high-spin natural-parity ''stretched configurations,'' for example (/sub ..lambda../d/sub 3/2,5/2/x/sub n/ f/sub 7/2//sup -1/)/sub 5/- or (/sub ..lambda../f/sub 5/2,7/2/x /sub n/ f/sub 7/2//sup -1/)/sub 6/+ in /sub ..lambda..//sup 48//Ca, for pion lab momentum p/sub ..pi../ in the range 1.02--1.1 GeV/c, where the elementary cross section for K/sup +/n..--> pi../sup +/..lambda.. has its peak values. The cross sections for the population of the natural-parity ground-state levels (/sub ..lambda../S/sub 1/2/x/sub n/l/sub l/+1/2 /sup -1/)/sub J/=l with closed-shell targets remain above 2 ..mu..b/sr at 0/sup 0/ for systems lighter than Aapprox. =50. The cross sections drop rapidly below p/sub ..pi../=1.02 GeV/c, due to threshold effects. Results are presented for the calculated quasielastic (quasifree) continuum background for the (..pi../sup +/, K/sup +/) reaction as a function of theta/sub 1ab/ and hypernuclear excitation energy. Because of the higher momentum transfer the quasielastic background is broader and significantly less in magnitude than that obtained in the (K/sup -/,..pi../sup -/) reaction at 0/sup 0/.

• Research Organization: Brookhaven National Laboratory, Upton, New York 11973
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 6822866
• Journal Information: Phys. Rev., C; (United States), Journal Name: Phys. Rev., C; (United States) Vol. 22:5; ISSN PRVCA
• Country of Publication: United States
• Language: English

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72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANGULAR DISTRIBUTION
ANGULAR MOMENTUM
BEAMS
BINDING ENERGY
BORN APPROXIMATION
BOSONS
CHARGED-PARTICLE REACTIONS
CROSS SECTIONS
DIFFERENTIAL CROSS SECTIONS
DISTORTED WAVE THEORY
DISTRIBUTION
DWBA
EIKONAL APPROXIMATION
ELEMENTARY PARTICLES
ENERGY
FEASIBILITY STUDIES
HADRON REACTIONS
HADRONS
HYPERNUCLEI
IMPULSE APPROXIMATION
ISOTOPE PRODUCTION
KAONS
KAONS PLUS
MATHEMATICAL MODELS
MESON BEAMS
MESON REACTIONS
MESONS
NUCLEAR FRAGMENTS
NUCLEAR MODELS
NUCLEAR REACTIONS
NUCLEI
PARITY
PARTICLE BEAMS
PARTICLE PROPERTIES
PION BEAMS
PION PLUS REACTIONS
PION REACTIONS
PSEUDOSCALAR MESONS
SHELL MODELS
SPIN
STRANGE PARTICLES
STRANGENESS-EXCHANGE REACTIONS