Exclusive production of p p. pi. sup +. pi. sup minus in photon-photon collisions

Journal Article · Wed Nov 01 00:00:00 EST 1989 · Physical Review (Section) D: Particles and Fields; (USA)

DOI:https://doi.org/10.1103/PhysRevD.40.2772· OSTI ID:5122871

Aihara, H ^[1]; Alston-Garnjost, M; Avery, R E; Barbaro-Galtier, A ^[2]

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1. University of Tokyo, Tokyo (Japan)
2. Lawrence Berkeley Laboratory, University of California, Berkeley, CA (USA)

We report a measurement of the {ital e}{sup +}{ital e}{sup {minus}}{r arrow}{ital e}{sup +}{ital e}{sup {minus}}{ital p}{bar p}{pi}{sup +}{pi}{sup {minus}} process with the TPC/Two-Gamma facility at the PEP {ital e}{sup +}{ital e}{sup {minus}} storage ring at SLAC. Forty-five {ital p{bar p}}{pi}{sup +}{pi}{sup {minus}} events were identified in data corresponding to an integrated {ital e}{sup +}e{sup {minus}} luminosity of 142 pb{sup {minus}1}. The cross section for {gamma}{gamma}{r arrow}{ital p{bar p}}{pi}{sup +}{pi}{sup {minus}} is given both as a function of the {gamma}{gamma} center-of-mass energy {ital W}{sub {gamma}{gamma}}, with {ital W}{sub {gamma}{gamma}} between 2.5 and 5.5 GeV, and as a function of the invariant mass squared {ital q}{sup 2} of one of the photons, with {minus}{ital q}{sup 2}{lt}7 GeV{sup 2}. This cross section falls much less rapidly with {ital W}{sub {gamma}{gamma}} than does the cross section for a similar process, {gamma}{gamma}{r arrow}{ital p{bar p}}. No {Delta}{sup 0}{bar {Delta}} {sup 0} production is observed, and only a small fraction of the events at low {ital W}{sub {gamma}{gamma}} is consistent with {gamma}{gamma}{r arrow}{Delta}{sup ++}{bar {Delta}} {sup {minus}{minus}}, {Delta}{sup ++}{bar p}{pi}{sup {minus}}, or {bar {Delta}} {sup {minus}{minus}}{ital p}{pi}{sup +}. In an expanded search through the same data, four events compatible with either {Lambda}{bar {Lambda}} ({Lambda}{r arrow}{ital p}{pi}{sup {minus}}) or {Sigma}{sup 0}{bar {Lambda}} ({Sigma}{sup 0}{r arrow}{Lambda}{gamma}) production were found.

• OSTI ID: 5122871
• Journal Information: Physical Review (Section) D: Particles and Fields; (USA), Vol. 40:9; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
PHOTON-PHOTON INTERACTIONS
EXCLUSIVE INTERACTIONS
ANTIPROTONS
CROSS SECTIONS
DECAY
ELECTRON-POSITRON INTERACTIONS
LAMBDA PARTICLES
PARTICLE PRODUCTION
PEP STORAGE RINGS
PIONS MINUS
PIONS PLUS
PROJECTION SPARK CHAMBERS
PROTONS
QUANTUM CHROMODYNAMICS
ANTIBARYONS
ANTIMATTER
ANTINUCLEI
ANTINUCLEONS
ANTIPARTICLES
BARYONS
BASIC INTERACTIONS
BOSONS
ELECTROMAGNETIC INTERACTIONS
ELEMENTARY PARTICLES
FERMIONS
FIELD THEORIES
GAS TRACK DETECTORS
HADRONS
HYPERONS
INTERACTIONS
LAMBDA BARYONS
LEPTON-LEPTON INTERACTIONS
MEASURING INSTRUMENTS
MESONS
NUCLEI
NUCLEONS
PARTICLE INTERACTIONS
PIONS
PSEUDOSCALAR MESONS
QUANTUM FIELD THEORY
RADIATION DETECTORS
SPARK CHAMBERS
STORAGE RINGS
STRANGE PARTICLES
645101* - High Energy Physics- Particle Interactions & Properties-Experimental- Electromagnetic Interactions & Properties