None
OVERALL NORMALIZATION ERROR NOT INCLUDED. -TMIN IS 0.015 (0.023) GEV**2 FOR THE LAMBDA (SIGMA0) REACTION.
INCLUDING NORMALIZATION UNCERTAINTY IN ERRORS. USING EMPIRICAL FITS TO D(SIG)/DT FOR -T > 1.0 GEV**2.
No description provided.
The reaction\(\bar pp \to \bar \Lambda \Lambda \) has been studied in a bubble chamber experiment at eight incident momenta between 1.50 and 2.06 GeV/c. The differential cross-section, the polarization and the spin correlation coefficients have been measured. They have been compared with the prediction of two theoretical models: the K-meson conspiracy and the exchange of the K*K** degenerate trajectory associated with a Regge cut. The latter model gives the best representation of the data.
No description provided.
No description provided.
POLARIZATION AND SPIN CORRELATION COEFFICIENTS. AVERAGED OVER ALL ANGLES. SEE PAPER FOR DEFINITIONS, MORE DETAILS AND POSSIBLE T-DEPENDENCE.
The target asymmetry for the reaction γ p → K + Λ 0 was measured at the Bonn 2.5 GeV synchroton. Data were taken at a fixed kaon c.m. angle of 90° and at photon energies between 1.1 and 1.3 GeV. The kaons were detected in a large aperture magnetic spectrometer.
5 PCT TARGET POLARIZATION UNCERTAINTY INCLUDED IN QUOTED ERRORS.
We have measured the difference between the pp total cross sections for parallel and antiparallel longitudinal spin states at beam momenta of 1.0, 1.1, 1.30, 1.58, 1.71, 2.1, and 2.25 GeV/c in a transmission counter experiment. These results reveal new structure in the plab range of 1.0 to 2.5 GeV/c.
No description provided.
We have measured the difference between the pp total cross-sections for parallel and anti-parallel longitudinal spin states at beam momenta of 3 and 6 GeV/ c . These results, combined with our previous measurements, at lower momenta, are useful in clarifying a striking structure appearing at around 1.5 GeV/ c . We have also measured for the first time, the spin-spin correlation parameter C LL ( t ) in pp elastic scattering at 6 GeV/ c . We observe evidence for an exchange with A 1 -like quantum-numbers.
THE NEW DATA ON THE LONGITUDINAL CROSS SECTION DIFFERENCE, SIG(NAME=CLL) AT 3 AND 6 GEV ARE INCLUDED IN THE RECORD OF I. P. AUER ET AL., PL 67B, 113 (1977).
NOTE: HIGHER -T DATA ARE BEING ANALYSED. PUBLISHED GRAPH HAS LARGER ERRORS.
THESE NUMBERS APPEAR TO UPDATE THOSE REPORTED IN I. P. AUER ET AL., PRL 37, 1727 (76). NOTE: DATA MAY HAVE SMALLER ERROR BARS IN THE FINAL ANALYSIS.
The polarization parameter P for the reactions p p → π − π + and p p → K − K + has been measured over essentially the full angular range at ll laboratory momenta between 1.0 and 2.2. GeV/ c , using a proton target polarized perpendicular to the scattering plane. The angles and momenta of both final state particles were determined from wire spark chambers, using the deflection caused by the polarized target magnet. Between 1000 and 5300 π − π + events, and 140 and 1300 K − K + events, were measured at each momentum. Differential cross sections for p p → π − π + were obtained. These are in excellent agreement with previous results. The polarization parameter for both channels is very close to +1 over much of the angular range. Legendre polynomial fits to the data are presented.
THE DIFFERENTIAL CROSS SECTIONS IN THIS EXPERIMENT AGREE WITH THE ONES FROM THE AUTHORS' EARLIER EXPERIMENT (E. EISENHANDLER ET AL., NP B96, 109(1975)) USING A LIQUID HYDROGEN TARGET, THOUGH THEY DO NOT CONSIDER THE PRESENT ONES QUITE AS RELIABLE.
No description provided.
No description provided.
Qausi-elastic ω production by ep scattering in the kinematic region 0.3. < Q 2 < 1.4 GeV 2 and 1.7 < W < 2.8 GeV was studied using a streamer chamber at DESY. The production angular distribution for γ V p → ω p has a strong non-peripheral component for W < 2 GeV. The ω production cross section falls by a factor of 4 as W changes from 1.7 to 2.8 GeV. In contrast the cross section for ω production with | t | < 0.5 GeV 2 is W independent between 1.7 and 2.8 GeV and for W > 2.0 GeV consistent in both W and Q 2 dependence with the predictions of a model based on one-pion exchange and diffraction.
FOR ALL T-VALUES. THE GAMMA* P TOTAL CROSS SECTION WAS TAKEN FROM A FIT TO THE DATA OF S. STEIN ET AL., PR D12, 1884 (1975). 'PPD'.
'PPD'. PERIPHERAL OMEGA PRODUCTION.
No description provided.
We have measured the total cross-section difference for pp scattering in initial spin states parallel to the beam direction at beam momenta of 1.17, 1.47, 1.69, 1.97 and 2.49 GeV/ c . This measurement was done in a standard transmission experiment. A striking energy dependence is observed with a maximum difference of −16.9 mb at P lab = 1.47 GeV/ c .
PRELIMINARY RESULTS.
PRELIMINARY RESULTS.
We have measured the polarization parameter in π−p elastic scattering at laboratory momenta of 1180, 1250, and 1360 MeV/c in the angular interval 65°<θc.m.<115°. The results were used to show that the polarized target used in these (and other similar) experiments was uniformly polarized. These measurements were also used to resolve pre-existing experimental discrepancies in the determination of the polarization parameter, and to clarify the behavior of scattering amplitudes in this energy range. We show that local measurements of this type are important in resolving discrete ambiguities affecting the energy continuation of the amplitudes. An important by-product of this experiment is the development of a fast method of reconstructing particle trajectories and fitting the elastic events, which could have a significant impact for future high-statistics experiments.
No description provided.
The reaction γ V p → p π + π − was studied in the W , Q 2 region 1.3–2.8 GeV, 0.3–1.4 GeV 2 using the streamer chamber at DESY. A detailed analysis of rho production via γ V p→ ϱ 0 p is presented. Near threshold rho production has peripheral and non-peripheral contributions of comparable magnitude. At higher energies ( W > 2 GeV) the peripheral component is dominant. The Q 2 dependence of σ ( γ V p→ ϱ 0 p) follows that of the rho propagator as predicted by VDM. The slope of d σ /d t at 〈 Q 2 〉 = 0.4 and 0.8 GeV 2 is within errors equal to its value at Q 2 = 0. The overall shape of the ϱ 0 is t dependent as in photoproduction, but is independent of Q 2 . The decay angular distribution shows that longitudinal rhos dominate in the threshold region. At higher energies transverse rhos are dominant. Rho production by transverse photons proceeds almost exclusively by natural parity exchange, σ T N ⩾ (0.83 ± 0.06) σ T for 2.2 < W < 2.8 GeV. The s -channel helicity-flip amplitudes are small compared to non-flip amplitudes. The ratio R = σ L / σ T was determined assuming s -channel helicity conservation. We find R = ξ 2 Q 2 / M ϱ 2 with ξ 2 ≈ 0.4 for 〈 W 〉 = 2.45 GeV. Interference between rho production amplitudes from longitudinal and transverse photons is observed. With increasing energy the phase between the two amplitudes decreases. The observed features of rho electroproduction are consistent with a dominantly diffractive production mechanism for W > 2 GeV.
DIPION CHANNEL CROSS SECTION.
THE TOTAL CROSS SECTION WAS OBTAINED BY THE AUTHORS FROM A FIT TO THE SINGLE ARM DATA OF S. STEIN ET AL., PR D12, 1884 (1975).
No description provided.