The reaction gamma p --> K0 Sigma+ was measured in the photon energy range from threshold up to 2.6 GeV with the SAPHIR detector at the electron stretcher facility, ELSA, in Bonn. Results are presented on the reaction cross section and the polarization of the Sigma+ as a function of the kaon production angle in the centre-of-mass system, cos(Theta_K^{c.m.}), and the photon energy. The cross section is lower and varies less with photon energy and kaon production angle than that of gamma p --> K+ Sigma0. The Sigma+ is polarized predominantly at cos(Theta_K^{c.m.}) \approx 0. The data presented here are more precise than previous ones obtained with SAPHIR and extend the photon energy range to higher values. They are compared to isobar model calculations.
Axis error includes +- 10/10 contribution (Normalization uncertainty already included.).
Axis error includes +- 10/10 contribution (Normalization uncertainty already included.).
Axis error includes +- 10/10 contribution (Normalization uncertainty already included.).
Electron-proton elastic scattering cross sections have been measured at four-momentum transfers between 1.0 and 3.0 (GeV/ c ) 2 and at electron scattering angles between 10° and 20° and at about 86° in the laboratory. The proton electromagnetic form factors G E and G M were determined. The results indicate that G E ( q 2 ) decreases faster with increasing q 2 than G M ( q 2 ).
Axis error includes +- 2.5/2.5 contribution (Due to counting statisticss, separation of elastic events, beam monitoring, incident energy, scattering angle, proton absorption, solid angle, target length and density).
CONST(NAME=MU) is the magnetic moment.
Quasielastic e-d scattering measurements were performed up to q 2 = 100 fm −2 . Only the electron was detected. The ratio R= ( d 2 ω d Ω d E′) ed d ω d Ω) ep was measured at the quasielastic peak; the magnetic form factor G M N of the neutron was deduced using the assumption G E N = 0.
No description provided.
CONST(NAME=MU) is the magnetic moment. The magnetic formfarctor (GM) is evaluated ander assumption of GE=0.
The total and the differential cross sections for the reaction e + e − → γγ ( γ ) have been measured with the DELPHI detector at LEP using an integrated luminosity of 36.9 pb −1 . The results agree with the QED predictions and consequently there is no evidence for non-standard channels with the same experimental signature. The lower limits obtained on the QED cutoff parameters are Λ + > 143 GeV and Λ − > 120 GeV, and the lower bound on the mass of an excited electron with an effective coupling constant λ γ = 1 is 132 GeV/ c 2 . Upper limits on the branching ratios for the decays Z 0 → γγ , Z 0 → π 0 γ , Z 0 → ηγ and Z 0 → γγγ have been determined to be 5.5 × 10 −5 , 5.5 × 10 −5 , 8.0 × 10 −5 , and 1.7 × 10 −5 respectively. All the limits are at the 95% confidence level.
1990 energies are 88.223, 89.222, 90.217, 91.217, 92.209, 93.208 and 94.202 GeV.. 1991 energies are 88.465, 89.460, 90.208, 91.225, 91.954, 92.953, and 93.703 GeV.. 1992 energy is 91.278 GeV.
Average of all data.
No description provided.
The differential cross section and analyzing power of the reaction pp → d π + were measured for nine incident proton energies between 725 and 1000 MeV. A magnetic spectrometer was used to detect either deuterons or pions. Cross-section and analyzing-power angular distributions were respectively fitted with Legendre polynomial and associated Legendre function expansions, the coefficients of which were found to vary smoothly with energy in the vicinity of the alleged 3 F 3 dibaryon resonance.
Data present here in form of Legendre polynomial fit.
Legendre Polynomial fit to cross section.
Legendre polynomial fit to analysing power.
The processes e + e − → e + e − and μ + μ − have been studied at PETRA using the JADE detector. The data, which were collected at s -values of up to 1300 GeV 2 have been analysed in terms of an electro-weak extension of QED to obtain values for the weak vector and axial vector couplings in the lepton sector. The values obtained agree with the predictions of the standard Salam-Weinberg model and the data are further analysed in terms of this model to obtain the limits 0.10 < sin 2 ϑ w < 0.40 (68% CL). The mass of the neutral weak gauge boson is deduced to be greater than 51 GeV/ c 2 .
No description provided.
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The final results of an experimental investigation of the reaction γ+n→p+π− performed with a deuterium bubble chamber at the 1 GeV Frascati electrosynchrotron are presented. Total and differential cross-sections on neutrons are extracted by means of the spectator model, the reliability of which has been checked by numerous tests and is extensively discussed. The problems of a possible isotensor component in the electromagnetic current, the time-reversal invariance of the electromagnetic interactions and the photoproduction of the Roper resonance are considered in detail.
No description provided.
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We have measured differential cross sections of γ + p → p + η 0 at several energies. The angular distributions show that S 11 production is predominant in the energy range investigated and that the other resonant terms seen in π-production of η are absent or very low. Finally, experimental data are theoretically interpreted and the S 11 parameters deduced.
No description provided.
No description provided.
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