Measurement of the total hadronic cross section in tagged. gamma. gamma. reactions

Journal Article · Tue May 01 04:00:00 EDT 1990 · Physical Review, D (Particles Fields); (USA)

DOI:https://doi.org/10.1103/PhysRevD.41.2667· OSTI ID:7098755

Aihara, H; Alston-Garnjost, M; Avery, R E; Barker, A R; Bauer, D A; Bay, A; Belcinski, R; Bingham, H H; Bloom, E D; Buchanan, C D; Caldwell, D O; Chao, H; Chun, S; Clark, A R; Cowan, G D; Crane, D A; Dahl, O I; Daoudi, M; Derby, K A; Eastman, J J ; Eberhard, P H; Edberg, T K; Eisner, A M; Erne, F C; Fairfield, K H; Fridman, A; Godfrey, G; Hauptman, J M; Ho, C; Hofmann, W; Kamae, T; Kenney, R W; Khacheryan, S; Kofler, R R; Lambert, D J; Langeveld, W G.J.; Layter, J G; Lin, W T; Linde, F L; Loken, S C; Lu, A; Lynch, G R; Lys, J E; Madaras, R J; Magnuson, B D; Marsiske, H; Masek, G E; Mathis, L G; Maxfield, S J; McNeil, R R; Miller, E S; Nicol, N A; Nygren, D R; Oddone, P J; Oh, H; Oyang, Y; Paar, H P; Palounek, A P.T.; Park, S K; Pellett, D E; Pripstein, M; Ronan, M T; Ross, R R; Rouse, F R; Schwitkis, K A; Sens, J C; Shapiro, G; Shen, B C; Smith, J R; Steinman, J S; Stephens, R W; Stevenson, M L; Stork, D H; Strauss,

We present a measurement of the total cross section for {gamma}{gamma}{r arrow}hadrons, with one photon quasireal and the other a spacelike photon of mass squared {minus}{ital Q}{sup 2}. Results are presented as a function of {ital Q}{sup 2} and the {gamma}{gamma} center-of-mass energy {ital W}, with the {ital Q}{sup 2} range extending from 0.2 to 60 GeV{sup 2}, and {ital W} in the range from 2 to 10 GeV. The data were taken with the TPC/Two-Gamma facility at the SLAC {ital e}{sup +}{ital e}{sup {minus}} storage ring PEP, which was operated at a beam energy of 14.5 GeV. The cross section exhibits a gentle falloff with increasing {ital W}. Its {ital Q}{sup 2} dependence is shown to be well described by an incoherent sum of vector-meson and pointlike scattering over most of the observed {ital W} range. Agreement at high {ital Q}{sup 2} is improved if a minimum-{ital p}{sub {ital T}} cutoff (motivated by QCD) is imposed on the pointlike contribution.

• OSTI ID: 7098755
• Journal Information: Physical Review, D (Particles Fields); (USA), Journal Name: Physical Review, D (Particles Fields); (USA) Vol. 41:9; ISSN PRVDA; ISSN 0556-2821
• 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
BASIC INTERACTIONS
COMPOSITE MODELS
CROSS SECTIONS
ELECTROMAGNETIC INTERACTIONS
ELEMENTARY PARTICLES
ENERGY RANGE
FERMIONS
FIELD THEORIES
FUNCTIONS
GAS TRACK DETECTORS
GEV RANGE
HADRONS
INTERACTIONS
LINEAR MOMENTUM
MATHEMATICAL MODELS
MEASURING INSTRUMENTS
PARTICLE INTERACTIONS
PARTICLE MODELS
PARTICLE PRODUCTION
PARTON MODEL
PEP STORAGE RINGS
PHOTON-PHOTON INTERACTIONS
POSTULATED PARTICLES
PROJECTION SPARK CHAMBERS
PROPAGATOR
QUANTUM CHROMODYNAMICS
QUANTUM FIELD THEORY
QUARKS
RADIATION DETECTORS
SPARK CHAMBERS
STORAGE RINGS
STRUCTURE FUNCTIONS
TOTAL CROSS SECTIONS
TRANSVERSE MOMENTUM
VECTOR DOMINANCE MODEL