$pi$to the minus + p $Yields$ $pi$$sup 0$ + n CHARGE EXCHANGE CROSS SECTIONS AT 20.7 AND 31.0 Mev

Journal Article · Fri Jun 15 04:00:00 EDT 1962 · Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D

DOI:https://doi.org/10.1103/PhysRev.126.2188· OSTI ID:4813416

Miyake, K; Kinsey, K F; Knapp, D E

Differential and total cross sections at 31.0 Mev and total cross sections at 20.7 Mev were measured for the reaction pi /sup -/ + p yields pi / sup o/ + n. A thin-walled liquid hydrogen target was used. The gamma telescopes used a Cerenkov counter to identify the conversion electrons and a thinlead converter to avoid complications from cascade processes. The angular distribution in mb/sr at 31.0 Mev is: d sigma /d OMEGA = (1.00 plus or minus 0.02)(STA0.51 plus or minus 0.04) - (0.61 plus or minus 0.11)P/sub 1/(cos th((0.12 plus or minus 0.36)P(cos theta )!. The total cross sections at 31.0 and 20.7 Mev are 6.5 plus or minus 0.5 and 5.4 plus or minus 0.4 mb, respectively. The data are analyzed in terms of the phase shrfts alpha /sub ij/ . Assuming that the S-wave phase shifts extrapolate to zero pion energy as alpha /sub i/ = alpha in, where n is the pion momentum in the c.m. system in units of m pi c, the quantity ( alpha /sub 1/- alpha /sub 3/ 0.02. This agrees with Hamilton and Woolcock' s prediction from photoproduction and the Panofsky ratio ( alpha /sub 1/- alpha /sub 3/)= 0.245 plus or minus 0.01. There are theoretical and experimental grounds for a nonlinear behavior of alpha /sub 3/ and alpha /sub 1/, which should improve the agreement. (auth)

• Research Organization: Univ. of Rochester, N.Y.
• NSA Number: NSA-16-026127
• OSTI ID: 4813416
• Report Number(s): NYO-9545; 0031-899X
• Journal Information: Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D, Journal Name: Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D Vol. Vol: 126; ISSN PHRVA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ANGULAR DISTRIBUTION
CHERENKOV COUNTERS
COINCIDENCE METHODS
CROSS SECTIONS
ELECTRIC CHARGES
ELECTRONS
ENERGY RANGE
HYDROGEN
INTERACTIONS
INTERNAL CONVERSION
MEASURED VALUES
NEUTRONS
PHASE SHIFT
PHOTOPRODUCTION
PHYSICS
PIONS
PIONS-MINUS
PROTONS
TARGETS