Results are reported on K − -neutron interactions at c.m. energies near 2 GeV. The interactions are dominated by strong production of hyperon resonances, particularly Σ(1385), Λ(1405) and Λ(1520). Production cross sections and angular distributions are given for the Σ(1385), Λ(1405) and Λ(1520) and branching fractions to decay modes observed in the experiment are given for Σ(1385) and Λ(1520). The strong energy dependence of some features of the data suggests that s -channel effects are dominant.
No description provided.
RESONANCE CROSS SECTIONS FOR <K- PI- P> FINAL STATE.
RESONANCE CROSS SECTIONS FOR <AK0 PI- N> FINAL STATE.
We present new measurements of the differential cross sections for K − p → K 0 n at 3, 4, 5 and 6 GeV/ c , where we have 248, 538, 761, and 376 events, respectively. Total cross sections are obtained by integrating the differential cross sections. We combine our data with other data from 3 to 15.7 GeV/ c to calculate an effective Regge trajectory for this reaction. Comparisons are made to predictions from exchange degeneracy and SU(3) sum rules.
No description provided.
No description provided.
No description provided.
Differential cross sections for the line-reversed reaction pairs K + 0p → K o Δ ++ (1236), K − n → K ̄ o Δ − (1236) and K − p → K ̄ o n , K + n → K o p have been measured with good statistics at 4 and 6 GeV/ c . The line reversal breaking for the Δ (1236) reactions is found to have no significant variation with energy and to be larger than for the charge exchange reactions. The cross sections for all four reactions show a dip in the forward direction, indicating the importance of spin-flip amplitudes.
Axis error includes +- 0.0/0.0 contribution (?////OVERALL NORMALIZATION ERROR AND BACKGROUND SUBTRACTION UNCERTAINTY).
Axis error includes +- 0.0/0.0 contribution (?////OVERALL NORMALIZATION ERROR AND BACKGROUND SUBTRACTION UNCERTAINTY).
Axis error includes +- 0.0/0.0 contribution (?////OVERALL NORMALIZATION ERROR AND BACKGROUND SUBTRACTION UNCERTAINTY).
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.
We have studied backward meson and baryon production in π−p→nπ+π− at 8 GeV/c using a streamer chamber triggered by the detection of the interaction of the neutron in thick-plate optical spark chambers. Our data sample of 866 events is dominated by the quasi-two-body final states Δ−(1232)π+, nρ0, and nf0. We study the differential and total backward cross sections for these states and the decay angular distributions of the resonances. The results for the Δ− and ρ0 indicate that both nucleon and Δ exchange in the u channel are important in their production, while f0 production is, as expected, consistent with nucleon exchange.
No description provided.
BACKWARD DIP.
No description provided.
We have measured the cross sections for the Okubo-Zweig-Iizuka-rule-violating reactions π+n→φp and π+p→φΔ++ at 10 GeV/c using the large-aperture-solenoid spectrometer at the Stanford Linear Accelerator Center. We measure the total cross sections for these two reactions to be 179±72 nb for the φp reaction and 172±75 nb for the φΔ++ reaction. Both of these cross sections are consistent with the hypothesis of the φ being produced solely by its nonstrange-quark component as determined from the octet-singlet mixing angle resulting from application of the Gell-Mann—Okubo mass formula to the vector-meson nonet. These data are thus inconsistent with an ideally mixed φ meson.
Axis error includes +- 0.0/0.0 contribution (RES-DEF(RES=DEL(1232P33)++,BACK=CORRECTED)//RES-DEF(RES=PHI,BACK=CORRECTED)//GLAUBER).
We have observed the decay h0(2040)→p¯p in the reaction π+n→p¯pp at 10 GeV/c detected in the large-aperture solenoid spectrometer at SLAC. We have measured the product of the cross section and branching ratio, σ(π+n→h0(2040)p)B(h0(2040)→p¯p), to be 0.84±0.17 μb. The moments of the angular distribution are consistent with the quantum numbers of the h0 meson being JPC=4++ and IG=0+.
Axis error includes +- 0.0/0.0 contribution (?/////BREIT-WIGNER PLUS POLYNOMIAL BACKGROUND FITTED TO P AP MASS DISTRIBUTION/REQUIRED THE MOMENTUM OF ONE P AND ONE AP TO BE >3 GEV, AND ONLY USED FOR THE FASTER P IN THE P AP MASS DISTRIBUTION).
We have studied the reactions π+n→K+K−p, π+p→K+K−Δ++, and π+p→(K+K−π+)p in 10-GeV/c π+d interactions using the large-aperture solenoid spectrometer at SLAC. We measure the cross sections times branching ratios for the production of the known meson resonances f(1270), g(1690), and h(2040). We also observe a new resonance with mass 2747±32 MeV, width 195±75 MeV, and production cross section times branching ratio into K+K−π+ of 0.84±0.08 μb. The data are consistent with the quantum numbers of this state being I=1, JP=7−.
No description provided.
No description provided.
No description provided.
We present a measurement of the total cross section for γγ→hadrons, with one photon quasireal and the other a spacelike photon of mass squared −Q2. Results are presented as a function of Q2 and the γγ center-of-mass energy W, with the Q2 range extending from 0.2 to 60 GeV2, and W in the range from 2 to 10 GeV. The data were taken with the TPC/Two-Gamma facility at the SLAC e+e− storage ring PEP, which was operated at a beam energy of 14.5 GeV. The cross section exhibits a gentle falloff with increasing W. Its Q2 dependence is shown to be well described by an incoherent sum of vector-meson and pointlike scattering over most of the observed W range. Agreement at high Q2 is improved if a minimum-pT cutoff (motivated by QCD) is imposed on the pointlike contribution.
Errors are statistical only.
Errors are statistical only.
Errors are statistical only.
The reaction e^+e^- -> e^+e^- proton antiproton is studied with the L3 detector at LEP. The analysis is based on data collected at e^+e^- center-of-mass energies from 183 GeV to 209 GeV, corresponding to an integrated luminosity of 667 pb^-1. The gamma gamma -> proton antiproton differential cross section is measured in the range of the two-photon center-of-mass energy from 2.1 GeV to 4.5 GeV. The results are compared to the predictions of the three-quark and quark-diquark models.
Total cross section for P PBAR production at a mean centre-of-mass energy of 197 GeV.
The cross section as a function of W for ABS(COS(THETA)) < 0.6.
The differential cross section as a function of COS(THETA*) for three W ranges.
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