Results are reported based on a study of 3114 π−p events at 205 GeV/c in the National Accelerator Laboratory 30-in. bubble chamber. The measured π−p total and elastic cross sections are 24.0 ± 0.5 and 3.0 ± 0.3 mb, respectively. The elastic differential cross section has a slope of 9.0 ± 0.7 GeV−2 for 0.03≤−t≤0.6 GeV2. The average charged-particle multiplicity for the inelastic events is 8.02 ± 0.12.

From measurements of proton-proton elastic scattering at very small momentum transfers where the nuclear and Coulomb amplitudes interfere, we have deduced values of ρ, the ratio of the real to the imaginary forward nuclear amplitude, for energies from 50 to 400 GeV. We find that ρ increases from -0.157 ± 0.012 at 51.5 GeV to +0.039 ± 0.012 at 393 GeV, crossing zero at 280 ± 60 GeV.

In an exposure of the 30-in. hydrogen bubble chamber to a 303−GeVc proton beam, 2245 interactions have been observed. The measured total cross section is 39.0±1.0 mb and the average charged particle multiplicity 〈nch〉=8.86±0.16.

We have measured $\rho$ , the ratio of the real to the imaginary part of the $p \bar{p}$ forward elastic scattering amplitude, at $\sqrt{s}$ = 1.8  TeV. Our result is $\rho$ = 0.132 $\pm$ 0.056; this can be combined with a previous measurement at the same energy to give $\rho$ = 0.135 $\pm$ 0.044.

Differential cross sections have been measured at Fermilab with a focusing spectrometer for π±p, K±p, and p±p elastic scattering at 50-, 70-, 100-, 140-, and 175-GeV/c incident momentum over the |t| range 0.03 to 0.8 GeV2. The results are smooth in t and are parametrized by quadratic exponential fits.

We have measured π+p, π−p, and pp elastic scattering at an incident-beam momentum of 200 GeV/c in the region of −t, four-momentum transfer squared, from 0.021 to 0.665 (GeV/c)2. The data allow an investigation of the t dependence of the logarithmic forward slope parameter b≡(ddt)(lndσdt). In addition to standard parametrization, we use functional forms suggested by the additive quark model to fit the measured dσdt distributions. Within the context of this model we estimate the size of the clothed quark in the pion and proton. Limits on the elastic-scattering amplitude derived from unitarity bounds are checked, and no violations are observed.

We have measured the elastic cross section for pp, p¯p, π+p, π−p, K+p, and K−p scattering at incident momenta of 70, 100, 125, 150, 175, and 200 GeV/c. The range of the four-momentum transfer squared t varied with the beam momentum from 0.0016≤−t≤0.36 (GeV/c)2 at 200 GeV/c to 0.0018≤−t≤0.0625 (GeV/c)2 at 70 GeV/c. The conventional parametrization of the t dependence of the nuclear amplitude by a simple exponential in t was found to be inadequate. An excellent fit to the data was obtained by a parametrization motivated by the additive quark model. Using this parametrization we determined the ratio of the real to the imaginary part of the nuclear amplitude by the Coulomb-interference method.

We present results from a measurement of the differential cross sections for Σ−p, Ξ−p, and π−p elastic scattering at 23 GeV/c. We have collected samples of 6200 Σ−p events, 67 Ξ−p events, and 30 000 π−p events in the interval 0.10<|t|<0.23 (GeV/c)2.

We report a measurement of the p p total cross section at √ s =1.8 TeV using a luminosity-independent method. Our result is σ T =72.1±3.3 mb ; we also derive the total elastic cross section σ el =16.6±1.6 mb. A value is obtained for the total single diffraction cross section of 11.7±2.3 mb.

In a 35 000-picture exposure of the 30-in. hydrogen bubble chamber to a 300-GeV/c proton beam at the Fermi National Accelerator Laboratory, 10054 interactions have been observed. The measured total cross section is $40.68 \pm 0.55$ mb, the elastic cross section is $7.89 \pm 0.52$ mb, and the average charged-particle multiplicity for inelastic events is $8.S0 \pm 0.12$.

We report a measurement of the p p ̄ total cross section at s =1.8 TeV at the Fermilab Tevatron Collider, using the luminosity independent method. Our result is σ T =71.71±2.02 mb. We also obtained values of the total elastic and total inelastic cross sections.

The differential cross section for elastic antiproton—proton scattering at s =1.8 TeV has been measured over the t range 0.034⩽| t |⩽0.65 (GeV/ c ) 2 . A logarithmic slope parameter, B , of 16.3±0.3 (GeV/ c ) −2 is obtained. In contrast to lower energy experiments, no change in slope is observed over this t range.

The antiproton-proton small-angle elastic-scattering distribution was measured at\(\sqrt s \) GeV at the Fermilab Tevatron Collider. A fit to the nuclear-scattering distribution in the range 0.065≤|t|≤0.21 (GeV/c)2 givesb=(16.2±0.5±0.5) (GeV/c)−2 for the logarithmic slope parameter. Using the optical theorem and the luminosity from Collider parameters, we obtain σtoto(1+ρ2)1/2 =(61.7±3.7±4.4)mb.

The energy dependence of backward π+p elastic scattering has been measured for incident π momenta 2.0-6.0 GeV/c in steps of typically 100 MeV/c. Values are presented for both the differential cross section extrapolated to 180° and the slope of the backward peak as a function of momentum. In the s channel we see the effects of the established Δ++ resonances and evidence for the Δ(3230). Also, the data show the existence of a negative-parity Δ resonance with mass ∼2200 MeV/c2.

The backward angular distributions obtained in an experiment at the Zero Gradient Synchrotron of Argonne National Laboratory were used to systematically study the energy dependence of the 180° differential cross section for π+p elastic scattering in the center-of-mass energy region from 2159 to 3487 MeV. At each of 38 incident pion momenta between 2.0 and 6.0 GeV/c, a focusing spectrometer and scintillation counter hodoscopes were used to obtain differential cross sections for typically five pion scattering angles from 141° to 173° in the laboratory. Values for dσdΩ at 180° were then obtained by extrapolation. A resonance model and an interference model were used to perform fits to the energy dependence of dσdΩ (180°). Both models led to good fits to our data and yielded values for the masses, widths, parities, and the product of spin and elasticity for the Δ(2200), Δ(2420), Δ(2850), and Δ(3230) resonances. Our data confirm the existence of the Δ(3230) and require the negative-parity Δ(2200).

A study of 205-GeV/c π−p interactions has been made with a 48 800-picture exposure in the bare Fermilab 30-inch hydrogen bubble chamber. The average number of charged particles produced per inelastic interaction is 7.99±0.06. The elastic cross section is 3.18±0.13 mb and the total cross section is 24.19±0.44 mb. The inclusive cross sections for neutral-particle production are: σ(γ)=171.3±15.3 mb, σ(KS0)=3.64±0.61 mb (x<0.3), σ(Λ)=1.71±0.34 mb (x<0.3), and σ(Λ¯)=0.59±0.23 mb (x<0.1). The average number of π0's produced per inelastic collision is consistent with a linear rise with the number of charged particles, and about equal to the number of produced π− or π+. The average number of K0's, Λ's, and Λ¯'s is consistent with very little dependence on the number of charged particles. General characteristics of neutral-particle production are presented and compared with other experiments. For each topology the produced neutral energy is ∼13 of the incident energy.

Angular distributions for π+p→π+p were measured for 13 incident-pion momenta from 4.4 to 6.0 GeV/c and for −t less than ∼0.1 (GeV/c)2. This experiment was performed at the Zero Gradient Synchrotron of Argonne National Laboratory, where a focusing magnetic spectrometer and a scintillation-counter hodoscope were used. In fitting the angular distributions the strong-interaction contribution was parameterized by an exponential form exp(bt); the Coulomb interference was also included. The resulting values of the slope parameter for |t|<∼0.1 (GeV/c)2 are presented for each incident beam momentum.

The elastic differential cross section for pp scattering has been measured up to a momentum transfer of ‖ t ‖ = 3(GeV/ c ) 2 at 100 GeV/c and 200 GeV/c incident momenta. The 200 GeV/ c measurements shows a diffractive like dip at ‖ t ‖ = 1.5 GeV/ c while no such dip is seen in the 100 GeV/ c data.

The differential cross section for π±, K±, and p± on hydrogen have been measured in the range 0.07<−t<1.6 (GeV/c)2. The dependence on momentum, momentum, transfer, and particle type are discussed.

Elastic scattering of hadrons on protons has been measured at momenta of 50, 100, and 200 GeV/c. The meson-proton scattering is found to be independent of momentum and meson type for −t>0.8 (GeV/c)2. The momentum dependence of the pp dip at −t=1.4 (GeV/c)2 was investigated. Slope parameters are given.

Results are presented on the measurement of 200-GeV/c π−p elastic scattering at −t from 0.8 to 11 (GeV/c)2. As −t is increased, dσdt falls by ∼6 decades to a prominent dip at 4 (GeV/c)2, followed by a second maximum and than a slow decrease with increasing −t.

Antiproton-proton elastic scattering has been measured at 100 GeV/c for 0.5<−t<2.5 (GeV/c)2 and at 200 GeV/c for 0.9<−t<4 (GeV/c)2. The data show that the −t≃1.4 (GeV/c)2 dip recently observed at 50 GeV/c persists to higher incident momenta. Proton-proton measurements made at the same beam momenta show similar structure.

Data are presented on elastic πp and Kp scattering for values of −t up to 2.5 and 3.5 (GeV/c)2 at incident momenta of 100 and 200 GeV/c, respectively. All of the cross sections are found to be nearly identical, although there is some momentum dependence of the π+p data; a small systematic difference observed between pion and kaon data cannot be explained by geometrical scaling.

Results are presented on π±p, K±p, and p±p elastic scattering measured with an apparatus having acceptance of 0.5<−t<2.5 (GeV/c)2 and 0.9<−t<11 (GeV/c)2 at 100 and 200 GeV/c, respectively. A diffractionlike dip is seen for the first time in the π−p t distribution at −t=4 (GeV/c)2. All meson-proton cross sections are found to be similar in the range 1<−t<2.5 (GeV/c)2, although some small systematic differences are observed. Cross sections for pp and p―p are compared with previous data.

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.