The total cross section of γ rays in hydrogen resulting in hadron production, σT, has been measured over the energy range 265-4215 MeV. A tagging system with narrow energy bins was employed. Structure in the resonance region followed by a steady fall with energy has been observed and the results are analyzed. The forward amplitude of γ-proton scattering is evaluated, and its behavior in the Argand diagram studied as a function of energy. The relationships of the measurements to Regge-pole theory and the vector-dominance model are detailed.
No description provided.
SPIN AVERAGED FORWARD COMPTON SCATTERING AMPLITUDE. IM(AMP) WAS CALCULATED VIA THE OPTICAL THEOREM FROM A SMOOTH FIT TO THE DATA, AND USED IN THE DISPERSION RELATION TO CALCULATE RE(AMP). AT THRESHOLD THE THOMSON AMPLITUDE IS -3.0 MUB*GEV.
The total electromagnetic cross sections of g-rays in hydrogen and deuterium have been measured over the energy range 265–4215 MeV using a photon tagging system. From these measurements, the total pair production cross sections are obtained, and the results are found to be in good agreement with the predictions of Jost, Luttinger and Slotnick.
Axis error includes +- 1/1 contribution.
Axis error includes +- 1/1 contribution.
The total cross section for photoproduction of hadrons on the deutron, σ T d , has been measured for photon energies in the range 0.265–40215 GeV. From this, using results for the photon total cross section, obtained previously with the same apparatus, the neutron total cross section has been determined in the resonance region. The resonant structure is found to be quite different from that for the proton. Thereafter the neutron cross section falls off steadily with energy, and the values obtained are consistently lower than those for the proton. Forward scattering amplitudes have been evaluated for the deuteron.
No description provided.
RESONANCE REGION. UNSMEARING CORRECTION APPLIED, GLAUBER CORRECTION NEGLIGIBLE.
HIGHER ENERGY CROSS SECTIONS, IN 200 MEV BINS. OVERALL 3 PCT SYSTEMATIC ERROR IN ADDITION TO QUOTED STATISTICAL ERRORS. NEUTRON/PROTON CROSS SECTION RATIO HAS MEAN VALUE OF 0.94 +- 0.01.
We have found 431 events of the reaction K+d→K0pps at 3.8−GeVc K+ beam momentum in a 295 000-frame exposure of the Argonne National Laboratory 30-in. deuterium-filled bubble chamber. The event sample consists of one- and two-prong events with a visible K0 decaying to π+π− The total and differential cross sections are found after correction for unseen K0's and for efficiencies in the scanning-measuring-fitting chain. Comparisons of the data are made to an SU(3) sum rule, a Regge model, and data for K−p→K¯0n.
No description provided.
GLAUBER SCREENING AND PAULI EXCLUSION PRINCIPLE CORRECTIONS ARE REQUIRED TO YIELD THE K+ N CHARGE EXCHANGE CROSS SECTION. THE GLAUBER CORRECTION IMPLIES AN INCREASE IN THE CROSS SECTIONS BY THE FACTOR 1.016. THE PAULI CORRECTION IS SLIGHT EXCEPT AT LOW -T (<0.2 GEV**2) WHERE IT IS LARGE AND UNCERTAIN.
A partial-wave analysis of the (K ππ ) 0 system produced in the charge exchange reaction K − p →( K 0 π + π − ) n has been made in the mass range 1.04 ⩽ M (K ππ ) < 1.56 GeV c data at 8, 10 and 16 GeV/ c . It was found that in about 2 3 of the cases, the (K ππ ) 0 system is produced in states of unnatural spin-parity, namely J P = 0 − and 1 + ; the rest is in the natural spin-parity state J P = 2 + state is consistent with being all K ∗ (1420). The unnatural spin-parity states are produced mostly (∼ 80% of the events) by natural parity exchange. The facts that unnatural spin-parity states are produced in this non-diffractive channel, with J P = 1 + dominant, and that the exchange responsible for their production is mostly of natural parity, are similar to what was found for the charged (K ππ ) − system in the diffractive reaction K − p→(K ππ ) − p. However, the absolute value and the energy dependence of the cross sections are very different in the two cases.
CORRECTED FOR UNSEEN AK0 DECAY MODES.
ACTUALLY CROSS SECTIONS FOR PRODUCTION IN MASS REGION 1.04 < M(AK0 PI+ PI-) < 1.56 GEV IN THE STATES JP = 1+, 2+ AND 0- RESPECTIVELY.
We have remeasured the total cross section for proton-proton scattering at 2-6 GeV/c in the spin states ↑↑ and ↑↓ perpendicular to the beam direction. With the reduced errors significant differences were found between the two cross sections.
DIFFERENCE OF TOTAL CROSS SECTIONS FOR ANTIPARALLEL AND PARALLEL SPINS PERPENDICULAR TO THE BEAM DIRECTION.
No description provided.
Cross sections are given for the various exclusive reactions K − p→ Λ 0 + n pions, as well as for quasi two-body final states involving ϱ 0 , ω 0 and Y 1 ∗ (1385) resonance production. The general features of Λ 0 production are presented as a function of the pion multiplicity n . Production of Y 1 ∗+ (1385) is clearly observed at all multiplicities while the Y 1 ∗− (1385) signals grow with the multiplicity, as expected in a non-exotic exchange picture. The polarisation of the Λ 0 is consistent with zero everywhere, except when it is a decay product of Y 1 ∗ (1385), when non-zero values are found for odd values of n . The reactions Λ 0 + 2π and Λ 0 + 3π are analysed in terms of the Plahte-Roberts model and good overall agreement is obtained for the various effective mass distributions and the p L ∗ , p T and cos θ distributions for the individual particles.
No description provided.
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No description provided.
No description provided.
The cross sections for the line-reversed reaction pairs K+n→K0p and K−p→K¯0n, and K+p→K0Δ++ and K−n→K¯0Δ− have been determined with high statistics and good relative normalization at 8.36 and 12.8 GeV/c in a spectrometer experiment at Stanford Linear Accelerator Center. The cross sections for the K+-induced reactions are larger than for the K−, contrary to the expectations of weakly-exchange-degenerate Regge-pole models. The ratio of the reaction cross sections is about the same as at lower energies and shows little change with momentum transfer.
Axis error includes +- 11/11 contribution.
Axis error includes +- 11/11 contribution.
Axis error includes +- 11/11 contribution.
The pp total cross section difference between pure transverse spin states was measured in the laboratory momentum range 1–3 GeV/ c . Significant differences were found and these differences show striking energy dependence. This structure is in disagreement with the predictions of simple exchange models.
No description provided.
REVISED DATA (J. D. LESIKAR, PRIV COMM, 19 JUN 1981). NOW CORRECTED FOR COULOMB-NUCLEAR INTERFERENCE. IN ADDITION, THE LOWEST MOMENTUM DATA POINT IS NOW KNOWN TO BE IN ERROR.
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