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

Journal Article · Wed Nov 01 04:00:00 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), Journal Name: Physical Review (Section) D: Particles and Fields; (USA) Vol. 40:9; ISSN 0556-2821; ISSN PRVDA
• Country of Publication: United States
• Language: English

Related Subjects

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