High-precision measurement of π−p elastic scattering in a wide angular range at incident momenta between 2.06 and 3.48 GeV/c

We have measured the differential cross section for π^?p elastic scattering at eight incident momenta, 2.06, 2.26, 2.45, 2.65, 2.86, 3.05, 3.26 and 3.48 GeV/c, in a wide range of c.m. scattering angle between 15° and 160°. A pronounced dip-bump structure has been found at large angles. Details of the structure are quantitatively described as functions of the incident momentum.     

Momentum spectra of secondary particles produced in proton-proton collisions at 14.2, 19.2 and 24.0 GeV/c

Results on charged particle yields in proton-proton collisions at 14.2, 19.2 and 24.0 GeV/c for secondary momenta above 4 GeV/c and lab angles between 10 and 150 mrad are reported. Cross sections for inclusive reactions involving the production of π^± K^±, p and $\text{p}$ are presented. The general features of the dependence of the data on transverse and longitudinal momentum, missing mass, and four-momentum transfer are described and the approach to limiting distributions in the 10 to 30 GeV energy range is discussed.     

K+P elastic scattering at 32 GeV/c

Elastic scattering of 32.1 GeV/c K⁺ on protons has been measured in a bubble chamber experiment. Results are presented in the momentum transfer interval 0.06–1.40 GeV² and compared with data at different energies. An effective Regge trajectory is calculated using K⁺p elastic data from 10 to 175 GeV/c.     

Soft π−p and pp elastic scattering in the energy range 30 to 345 GeV

Differential cross sections for π^?p and pp elastic scattering have been measured at incident momenta ranging from 30 to 345 GeV and in the t range 0.002 (GeV/c)² ? |t| ? 0.04 (GeV/c)². From the analysis of the data, the ratio ? (t = 0) of the real to the imaginary parts of the forward scattering amplitude was determined together with the logarithmic slope b of the diffraction cone.The results on the real parts confirm the validity of the forward dispersion relations at high energies. Using the dispersion relations, it was shown that the experimental data on ?_{π?p(t = 0)} require a continuous rise of the total πp cross sections, at least up to the energy of 2000 GeV, thus revealing a close similarity in high-energy behaviour of πp and pp interactions.The results on the slope parameters from this experiment together with the analysis of the available world data demonstrate that the existing experimental data are consistent with the hypothesis of a universal shrinkage of the hadronic diffraction cone at high energies. The value of the asymptotic shrinkage parameter α_p^′ was found to be independent of the kind of the incident hadron and of the momentum transfer in the t range |t| ? 0.2 (GeV/c)² : 2α_{p^′ = ± 3 (GeV/c)^?2}.     

αα elastic scattering at 4.32 GeV/c and 5.07 GeV/c

αα elastic scattering was measured at 4.32 GeV/c and 5.07 GeV/c incident momenta. The four-momentum transfer range, extending from ?0.05 to ?0.77 (GeV/c)², covers the first and second minimum regions. The results are compared with calculations based on Glauber theory.     

Experimental study of Λp and Ξ0p interactions in the range 1 – 10 GeV/c

The reactions Λp → Λp, → Σ^±pπ^?, → Λpπ⁺π^? and → Σ⁰p have been studied in the SLAC 82 inch bubble chamber for incident Λ particles in the momentum range 1–10 GeV/c. The incident Λ flux was produced by the exposure of a platinum target mounted inside the chamber to a 12 GeV K^? beam. A total of 992 events have been analyzed. The reactions are found to be qualitatively similar to corresponding nucleon-nucleon reactions. In particular, the slope parameter B in the elastic cross section dσ/dt = Ae^Bt has been determined as a function of incident momentum and found to be consistent with that for proton-proton elastic scattering. Angular distributions for the inelastic channels are compared with those of similar nucleon-nucleon reactions, and predictions of relevant exchange models.     

Neutron-proton elastic scattering from 10 to 70 GeV/c

The neutron-proton elastic differential cross section has been measured for incident momenta between 10 and 70 GeV/c and for values of the momentum transfer squared between 0.1 and 2.8 (GeV/c)². The forward peak and the break at about ∣t∣ = 1 (GeV/c)² are very similar to corresponding pp data.     

K−p elastic scattering at 14.3 GeV/c

Results are presented of a bubble chamber experiment on K^?p elastic scattering at 14.3 GeV/c, in four-momentum transfer range 0.04 < |t| < 2.74 GeV² using an initial set of 40 000 events. The total elastic cross section is (2.96 ± 0.10) mb. The results are compared with K⁺p elastic scattering data at 13.8 GeV/c, and the effective Regge trajectory is calculated using K^?p data from 5 to 100 GeV/c.     

Structure in momentum-transfer for (pπ−) systems produced in diffractive dissociation of neutrons on protons

The four-momentum transfer distribution of (pπ^?) systems produced in the neutron dissociation reaction n + p → (pπ^?) + p has substantial structure which depends strongly on the mass and on the angular decay properties of the produced (pπ^?) system. No significant energy dependence is observed in the data for incident neutrons in the momentum range between 50 GeV/c and 300 GeV/c. The results are compared with a Deck-type of model.     

Search for narrow baryons in π−p elastic scattering at large angles

Hoping to find resonant structures in the momentum dependence of π^?p elastic scattering we have measured the differential cross section for this reaction at c.m. angles near 90°. An intense pion beam (≈ 10⁷π/s) has been used, together with a high incident momentum resolution (dP/P ≈ 2 × 10^?4), to scan the region of laboratory momenta from 5.75 to 13.02 GeV/c (c.m. energy from 3.42 to 5.03 GeV). The sensitivity attained by the experiment is such that signals would have been seen corresponding to the formation of non-strange baryon resonances having width larger than ≈ 0.1 MeV and elasticity larger than a few per cent. Within these limits no resonances were sighted.     

Coulomb-nuclear interference in π±p and K±p elastic scattering below 3 GeV: Measurements,real parts and K±p dispersion relations

The differential cross sections for π⁺p elastic scattering at0.6, 1.0, 1.5, 2.0, GeV/c for π^-p at 1.0, 1.5, 2.0 GeV/c, for K^-p at 1.2, 1.8, 2.6 GeV/c and for K^-p at 0.9, 1.2, 1.4, 1.6, 1.8, 2.6 GeV/c have been measured with an overall accuracy ofthe order of 1 to 2% in an electronics experiment over the angular region corresponding to momentum transfer t between 0.0005 and 0.10 GeV². Making use of the interference effects between the Coulomb and the nuclear interaction, we have determined the magnitude and sign of the real part of the scattering amplitude near t = 0. The K^±p real parts have been used in a dispersion relation to derive the value of the KNΛ coupling constant.     

The structure of the high-momentum parts of the deuteron spectra from d-d collisions at 4.3, 6.3 and 8.9 GeV/c

The experimental data on d-d collisions at 4.3, 6.3 and 8.9 GeV/c, exhibiting the two-peak structure in the high-momentum parts of the secondary deuteron spectra at momentum transfers |t| ≈ 0.4–0.8 (GeV/c)², are presented. An analysis of the results in terms of the multiple nucleon-nucleon scattering model is given. Some conclusions about the mechanism of the elastic and quasielastic d-d scattering at the above-mentioned momentum transfers are made.     

Higher moments of the pion multiplicity distribution in proton-proton interactions at 12 and 24 GeV/c

Results on higher moments of the pion multiplicity distribution are presented for pp interactions at 12 and 24 GeV/c incident lab momentum. A simple parametrization for the pion multiplicity distribution is established at 12 and 24 GeV/c and is then used to discuss the energy dependence of higher moments in a range from 4 to about 500 GeV/c incident lab momentum.     

Measurement of polarization in K−p elastic scattering between 0.955 GeV/c and 1.272 GeV/c

The polarization parameter has been measured for K^?p elastic scattering at nine incident beam momenta between 0.955 and 1.272 GeV/c covering the c.m. angular range $\text{?0.9 < cos θ}{}^1\text{< + 0.9}$. Experimental results and coefficients of Legendre polynomial fits to the data are presented and compared with other measurements and a partial-wave analysis.     

Fluctuations in large-angle πp elastic scattering at 5 GeV/c

In a re-analysis of large-angle π^±p elastic scattering cross-sections at 5 GeV/c the data were divided in two momentum bins separated by approximately 80 MeV/c. For π^±p the differential cross-sections are found to fluctuate considerably between the two momentum bins, whereas for π^?p no fluctuations are observed. The result is interpreted as possible evidence for Ericson fluctuations.     

The NΛK coupling constant

A dispersion relation analysis has been performed using the real parts of the K^±p forward scattering amplitudes measured over the incident momentum region from 1 to 3 GeV/c by the electronics experiment of the preceding letter. Two possible values are found for the NΛK coupling constant. One of them is in very good agreement with the symmetry theory predictions.     

Measurement of the tensor A yy and vector A y analyzing powers of the deuteron inelastic scattering of beryllium at 5.0 GeV/c and 178 mrad

Tensor A _yy and vector A _y analyzing powers in the inelastic scattering of deuterons with a momentum of 5.0 GeV/c on beryllium at an angle of 178 mrad in the vicinity of the excitation of baryonic resonances with masses up to ～ 1.8 GeV/c ² have been measured. The A _yy data are in good agreement with the previous data obtained at 4.5 and 5.5 GeV/c. The results of the experiment are compared with the predictions of the plane-wave impulse approximation and ω meson-exchange models.     

π+p and K+p elastic scattering at 250 GeV/c

Results are presented on π⁺p and K⁺p elastic scattering at 250 GeV/c, the highest momentum so far reached for positive meson beams. The experiment (NA22) was performed with the european hybrid spectrometer. The π⁺p elastic cross section stays constant with energy while the K⁺p cross section increases.     

Measurement of np elastic scattering at high energies and very small momentum transfers

The np elastic differential cross section has been measured for incident neutron momenta 100–400 GeV/c in the |t| range 6 · 10^?6 ? 5 · 10^?1 (GeV/c)². The np data of this experiment provide a first direct measurement of the hadronic amplitude for |t| < 10^?2 (GeV/c)², which is consistent with the extrapolations from higher |t| values. Our data for |t| < 10^?4 (GeV/c)² are consistent with a rise which can be attributed to Schwinger scattering, caused by the interaction of the neutron magnetic moment with the proton.