This paper describes a measurement of the neutron-proton differential cross section made at the Argonne National Laboratory Zero Gradient Synchrotron. The differential cross sections, based on about 470 000 events, are presented for 8 different momentum ranges between 4.5 and 12.5 GeV/ c . The data extend from small angles out to about 145° in the c.m.s., corresponding to 0.14 < − t ⪅ 19 (GeV/ c ) 2 at the highest energies. These results in conjunction with previous np charge-exchange data provide almost complete angular distributions in this momentum range. A detailed comparison of the data with existing pp data and with theoretical predictions is made.
No description provided.
We have measured with good statistics the differential cross section for p p →π + π − , K + K − around 0°. Our data and previous results show that the s -dependence of dσ/d t has a value compatible with the appropriate baryon exchange.
No description provided.
No description provided.
No description provided.
We present experimental data on the K L 0 p → K S 0 p reaction between 4 and 14 GeV/ c in the range 0.1 ≲ | t | ≲ 2 GeV 2 . This experiment has been performed at the CERN PS, using spark chambers and a large aperture magnet. The results show a break of slope at t = −0.3 GeV 2 . The ω trajectory deduced from the data has an intercept α (0) = 0.5 and a slope α ′ = 0.88. A comparison with various models shows that the non-flip amplitude is dominant.
No description provided.
Data are presented which firmly establish the existence of the double charge exchange reaction p p → Σ − Σ − at 3.6 GeV/ c . The forward cross section was found to be (5.9 ± 1.1) μb and the ratio of the “forbidden” to “allowed” forward cross section is R = σ( Σ − Σ − σ( Σ + Σ + ) = 0.09 ± 0.02 .
No description provided.
No description provided.
Final state resonance production and single particle momentum spectra are presented for p p annihilations into K K and π's between 1.09 and 3.45 GeV/ c . Resonance production generally agrees with the Lamb statistical model. Momentum spectra of K's and π's are independent of incident energy, while the mean multiplicity increases in proportion to the c.m. energy, supporting the annihilation model of Jacob and Nussinov.
THESE CROSS SECTIONS WERE GIVEN IN DETAIL IN B. Y. OH ET AL., NP B51, 57 (1973).
No description provided.
A systematic study of p p and p d topological and reaction cross sections between 1.51 and 2.90 GeV/ c has been completed. The data have been analysed in relation to the three known structures at c.m. N N energies of 2190, 2350 and 2375 MeV. The data suggest that four- and six-pion annihilations of antiprotons on neutrons may be the source of the 2350 MeV effect. Further data below 1.60 GeV/ c are required to verify this tentative conclusion.
No description provided.
INCLUDING 3 PCT SYSTEMATIC ERROR.
No description provided.
High statistics data on p p annihilation into five and more pions at 2.32 GeV/ c are presented. Cross sections for various final states and for the production of meson resonances have been determined. The Dalitz plot asymmetry for some 4 800 ω decay events produced in p p → 2π + 2π − π 0 is found to be consistent with zero. Upper limits for the production of exotic meson resonances are presented.
No description provided.
The p p → n n polarization has been measured at 8 GeV/ c and for − t values ranging from 0 up to 0.8 (GeV/ c ) 2 . A small and negative polarization has been found.
ERRORS INCLUDE STATISTICAL AS WELL AS RELATIVELY SMALL SYSTEMATIC EFFECTS.
The differential cross section for the charge exchange p p → n n has been measured with high statistics at 7.76 GeV/ c and at 5.0 GeV/ c . The 7.76 GeV/ c data show a very narrow [ Δt ⪅ 0.01 (GeV/ c ) 2 ] forward peak superposed on a slow exponential fall-off.
No description provided.
No description provided.
INTEGRATED CROSS SECTIONS FROM EXPONENTIAL FIT.
We present measurements from a spark chamber experiment of the differential cross-sections for p p → π − π + , K − K + at 20 momenta in the range 0.8–2.4 GeV/ c (c.m. energy 2.02 to 2.57 GeV). The c.m. angular range was −0.95 < cos θ ∗ < 0.95 . There are about 2000π − π + events and about 300 K − K + events at each momentum.
ALL ANGLES.
We present complete results concerning the five reactions K − p → Λω , K − p → Λφ , K − p → Σ 0 ϱ and K − p → Σ 0 φ . The experimental data are well described by exchange mechanisms and the agreement with the SU(3) symmetry predictions is excellent.
FORWARD AND BACKWARD CROSS SECTIONS ARE FOR COS(THETA) > AND < 0. SLOPE DETERMINED FOR -TP = 0.2 TO 1.0.
AUTHORS ALSO GIVE CORRELATIONS OF LAMBDA POLARIZATION WITH THE MESON POLARIZATION.
No description provided.
We report on experimental results on proton-deuteron elastic scattering at a centre-of-mass energy of √ s = 63 GeV . The data were obtained using the Split Field Magnet detector at the CERN Intersecting Storage Rings. The t -dependence of the elastic differential cross section, measured up to − t = 2.0 GeV 2 , is compared with the prediction of an extended Glauber theory including contributions from inelastic intermediate states. Discrepancies of up to 30% with the basic theory are observed in the interference region. The inelastic contributions are essential for the detailed description of the data both in the single- and double-scattering regions.
No description provided.
No description provided.
We report on experimental results on deuteron-deuteron elastic scattering at a centre-of-mass energy of √ s = 53 GeV . The data were obtained using the Split Field Magnet detector at the CERN intersecting Storage Rings. The t -dependence of the elastic cross section is measured up to − = 1.5 GeV 2 . We observed a narrow interference minimum in the differential cross section at − = 0.18 GeV 2 . The inclusion of inelastic intermeduate states in the multiple scattering Glauber theory is essential in the description of the data over the entire t -range where discrepancies of up to 25% are observed with the basic theory.
No description provided.
No description provided.
Channel cross sections have been determined for p p annihilations into final states containing 3 to 9 pions at 4.6 GeV/ c . The moments of both the charged and neutral pion multiplicity distributions are presented and model predictions are critically examined.
No description provided.
Polarization and differential cross-section data are presented for elastic scattering of antiprotons on polarized protons at eight momenta between 0.9 and 2.5 GeV/ c . The data are fitted with a diffraction model.
COMBINED 0.88 AND 0.95 GEV/C DATA.
COMBINED 1.00 AND 1.04 GEV/C DATA.
COMBINED 1.01 AND 1.055 GEV/C DATA.
None
Axis error includes +- 10/10 contribution (COMPOUNDED WITH STATISTICAL ERROR).
Axis error includes +- 10/10 contribution (COMPOUNDED WITH STATISTICAL ERROR).
Axis error includes +- 10/10 contribution (COMPOUNDED WITH STATISTICAL ERROR).
A search for N ∗ (1450) production has been made among the 904 selected examples of the reaction pd → pp π − (p sp ) obtained in a bubble chamber exposure at 5.9 GeV/ c incident momentum. The cross section for the reaction pn → pp π − is found to be 1.4 ± 0.1 mb. The peripheral data are in good agreement with the predictions of a single-pion exchange model. Approximately 8% of the events can be attributed to N ∗ (1450) production by some other mechanism.
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.
A study of pp interactions at an incident momentum of 16.2 GeV/ c leading to two-prong non-strange final states was carried out in an exposure of the 2m CERN hydrogen bubble chamber. The c.m. angle and momentum distributions for the outgoing particles in the final states pn π + and pp π 0 are presented and discussed. These final states were analysed in terms of quasi two-body final states - N(Nπ), with the pion-nucleon system in an I = 1 2 or I = 3 2 state. A determination of these two isospin amplitudes and their interference term is then carried out. The reaction pp → pn π + is found to be well described by a Reggeized exchange model, as well as by a double Regge-exchange model.
No description provided.
Differential cross sections for center of mass scattering angles near 90° are presented for the reactions K ̄ ° p → π + Λ° , K ̄ ° p → π + Σ° and K L °p → K S °p in the momentum interval 1.0 to 7.5 GeV / c . The energy dependences of these cross sections are found to be equally well described by the parameterization: ( d σ d Ω ) 90° ∞ s −2 or ( d σ d Ω ) 90° ∞ exp (− bp ⊥ ) .
No description provided.
No description provided.
No description provided.
Cross sections, differential cross sections, and hyperon polarization results are presented for the reactions K¯0p→Λπ+ and K¯0p→Σ0π+ in the momentum interval 1 to 12 GeV/c. Emphasis is placed on the comparison of Λ and Σ channels, and on the momentum dependences of the data. In particular, the Λ polarization data are consistent with being independent of energy above 2 GeV/c; and the slopes of the forward cross sections are found to increase toward the slope values for the line-reversed reactions πp→K(Λ,Σ) as energy increases.
No description provided.
No description provided.
RESONANCE REGION CROSS SECTIONS.
The differential cross sections for KL0p→KS0p scattering are presented in several momentum intervals between 1 and 10 GeVc. The data are strongly peaked in the forward direction, characteristic of a large s-channel helicity-nonflip scattering amplitude in this reaction, and a distinct break in the differential cross section occurs at |t|=0.3 GeV2. The phase of the forward scattering amplitude, φ, is consistent with being independent of momentum. The average value of the phase, φ=−133.9±4.0∘, corresponds to a Regge trajectory α(0)=0.49±0.05 in agreement with the canonical ρ, ω0 Regge intercept, α(0)∼0.5. However, this result disagrees with the Regge trajectory determined from the energy dependence of the forward cross section, α(0)=0.30±0.03, indicating a breaking of the Regge phase-energy relation. Comparisons of KL0p→KS0p and π−p→π0n scattering data reveal substantial differences in the energy dependence of the differential cross sections. Comparisons to KN charge-exchange data then suggest that direct-channel (absorption) effects may explain the differences in πN and KN channels.
No description provided.
No description provided.
No description provided.
Backward scattering in the reaction KL0p→pKS0 is studied in the momentum interval 1.0 to 7.5 GeV/c. Comparison of KL0p→pKS0 and K+p→pK+ backward scattering, where respectively Σ exchange and Λ plus Σ exchange can contribute in the u channel, reveals that dσdΩ180°(KL0p→pKS0dσdΩ180°(K+p→pK+) above the resonance region. This result provides direct evidence for the dominance of the Λ contribution over the Σ contribution in the K+p→pK+ production amplitude.
No description provided.
The process pn → pp π − is studied in pd collisions at 11.6 GeV/ c . A broad low-mass enhancement of p π − is found in the diffractive reaction pn → p(p π − ) with a cross section slightly smaller than that of a similar analysis at 7.0 GeV/ c . The non-diffractive reaction pn → (p π − )p shows some evidence for resonance production and its cross-section dependence on energy is characteristic of meson exchange. Samples of mass, momentum transfer, and decay angular distributions are compared with the predictions of a double Regge model and a reggeized one-pion exchange model. Using in addition information from the reactions pp → pp π 0 , pp → pn π + at 12.0 GeV/ c , an isospin analysis of the single pion production reaction from nucleon-nucleon scattering, N 1 N 2 → N 3 (N 4 π ) is presented.
NON-DIFFRACTIVE CHARGE-EXCHANGE CROSS SECTIONS.
The reaction pn → pp π − at 7.0 GeV/ c is studied in a pd experiment. Observations on isobar production and low-mass enhancement are reported. The I = 1 2 isobars and the low-mass enhancement produced at the neutron vertex are discussed in terms of the diffraction dissociation plus duality model.
PART OF THE DIFFERENCE BETWEEN DEL PRODUCTION AT THE NEUTRON AND AT THE PROTON VERTICES COULD ARISE FROM DEUTERON EFFECTS.
Forum