From a 150 000-photograph exposure, we analyzed the p¯d→p¯psn reaction, ps denoting a proton stopping in the deuterium-filled bubble chamber. Choosing kinematical regions in which the ps can be recognized as a spectator, we studied the p¯n→p¯n process. From the observed p¯n diffraction peak, we obtained an exponential slope for the four-momentum-transfer distribution of bn=9.4±0.8 (GeV/c)−2, the elastic p¯n cross section being estimated as σe(p¯n)=16.5±2.4 mb. The present values in conjunction with those obtained at ≈1.8 and 3.5 GeV/c show that in this region bn and σe(p¯n) decrease with increasing incident momentum. We compared our data with the reactions np→np at ≈5.4 GeV/c and p¯p→p¯p at 5.7 GeV/c. The p¯n→p¯n and np→np differential cross sections exhibit a crossover phenomenon while p¯p and p¯n elastic scattering show an isospin dependence. We also analyzed the p¯d→p¯psn reaction by means of the Glauber formalism.
No description provided.
No description provided.
The s and t dependence of φ (1019) photoproduction has been investigated in the incident photon energy range 2.8 to to 4.8 GeV. Differential cross-sections and density matrix elements are presented for a t range extending from t min out to −1.3 (GeV/ c ) 2 . The results are discussed in terms discussed in terms of an effective Regge trajectory in the t -channel.
DIFFERENTIAL CROSS SECTIONS AVERAGED OVER TWO RANGES OF INCIDENT PHOTON ENERGY.
VARIATION OF SMALL -T DIFFERENTIAL CROSS SECTION WITH PHOTON ENERGY.
INTERCEPT AND SLOPE FROM FITS TO D(SIG)/DT AT SMALL -T.
Differential and total cross-sections for photoproduction of gamma proton to proton pi0 omega and gamma proton to Delta+ omega were determined from measurements of the CB-ELSA experiment, performed at the electron accelerator ELSA in Bonn. The measurements covered the photon energy range from the production threshold up to 3GeV.
Differential cross section as a function of the OMEGA angle.
Differential cross section as a function of the OMEGA angle.
Differential cross section as a function of the PI0 angle.
We have measured ρ0, ω (combined) and ϕ electroproduction over a range of virtual-photon four-momentum Q2 from 0.4 to 2.2 GeV2 and for photon energies ν from 2.7 to 8.6 GeV. We find that the slope of the t (momentum transfer) dependence of the ρ0 and ω forward peak decreases with increasing Q2 to less than half of the photoproduction slope.
The cross section for virtual photon are derived from E- P cross section bydividing on the virtual-photon flux factor.
The slope b(s) of the forward diffraction peak of p−p elastic scattering has been measured in the momentum-transfer-squared range 0.005≲|t|≲0.09 (GeV/c)2 and at incident proton energies from 8 to 400 GeV. We find that b(s) increases with s, and in the interval 100≲s≲750 (GeV)2 it can be fitted by the form b(s)=b0+2α′lns with b0=8.23±0.27, α′=0.278±0.024 (GeV/c)−2.
MOMENTUM BINS ARE APPROX 20 GEV WIDE CENTRED AT THE GIVEN PLAB EXCEPT FOR THE 9 AND 12 GEV POINTS WHICH HAVE WIDTHS OF APPROX 1 AND 4 GEV RESPECTIVELY.
A sample of 43000 two-prong events obtained at a momomentum of 11.7 GeV/c is used to determine the cross-sections of the fitted channels, and to study the reaction π+p→π+pπ0. We investigate in particular the quasi-two-body channels π0Δ++ and ρ+p.
No description provided.
No description provided.
No description provided.
We have analyzed backward meson production in the reaction π − p → p f π + π − π − at 9 GeV/ c and 12 GeV/ c incident π − momenta, from an experiment performed at the CERN Ω Spectrometer using a fast proton (p f ) trigger device. We find strong production of quasi-two-body processes N ∗ ϱ and N ∗ f with a production mechanism consistent with u -channel nucleon exchange. At a lower level, we observe N ∗ π processes with a 3-body baryon decay through Δ(1232)π. In the (3π) − system, we find evidence for A 1 − and clear A 2 − backward production with similar cross sections (≈0.5 μb).
No description provided.
U-HELICITY JACKSON FRAME.
U-HELICITY JACKSON FRAME.
Angular distributions are presented for p¯−p elastic scattering at 8 and 16 GeV/c for |t|<1.3 (GeV/c)2. At both energies there is structure in the differential cross sections in the region 0.5<~|t|<~1.0 (GeV/c)2, similar to that observed at lower energies. The diffraction peak continues to expand with increasing incident momentum.
No description provided.
No description provided.
No description provided.
High-statistics measurements of the absolute differential cross section for n−p scattering have been made over neutron c.m.-system scattering angles 9.5°<θ*<64.5°. The statistical error is 1.7 to 3.3% for 2°-wide angular bins, and the systematic error is 2.7 to 3.3%. The cross section is fitted by dσdΩ*=A exp(bt), with A=10.27±0.36 mb/sr, b=5.00±0.05, and 0.01<−t<0.39 (GeV/c)2. For the ratio of the real to the imaginary part of the forward-scattering amplitude we obtained αn>~−0.43±0.04, consistent with other less precise determinations of αn.
EXPONENTIAL FIT TO D(SIG)/DOMEGA OVER -T = 0.01 TO 0.39 GEV**2 (THETA = 9.5 TO 64.5 DEG).
We have analysed about 85 000 fast Λ 0 events, obtained in a fast proton triggered experiment performed at the CERN-Ω spectrometer at 9 and 12 GeV/ c incident π − beam. Nearly 2500 Λ 0 K + π − events have been isolated. We find strong production of quasi-two-body processes Λ 0 K ∗0 and ∑ ∗− K + consistent with u -channel hyperon exchange. Results on Λ 0 polarization, K ∗0 decay parameters and differential cross sections are given for Λ 0 K ∗0 (892) and Λ 0 K ∗0 (1430) final states. A comparison is made with the associated backward Λ 0 (1520) K ∗0 production seen in the four-prong reaction π − p→pK − K + π − obtained in the same experiment.
No description provided.
No description provided.
EXPONENTIAL FIT TO DN/DU.
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