A measurement of the total $pp$ cross section at the LHC at $\sqrt{s}=7$ TeV is presented. In a special run with high-$\beta^{\star}$ beam optics, an integrated luminosity of 80 $\mu$b$^{-1}$ was accumulated in order to measure the differential elastic cross section as a function of the Mandelstam momentum transfer variable $t$. The measurement is performed with the ALFA sub-detector of ATLAS. Using a fit to the differential elastic cross section in the $|t|$ range from 0.01 GeV$^2$ to 0.1 GeV$^2$ to extrapolate to $|t|\rightarrow 0$, the total cross section, $\sigma_{\mathrm{tot}}(pp\rightarrow X)$, is measured via the optical theorem to be: $$\sigma_{\mathrm{tot}}(pp\rightarrow X) = 95.35 \; \pm 0.38 \; ({\mbox{stat.}}) \pm 1.25 \; ({\mbox{exp.}}) \pm 0.37 \; (\mbox{extr.}) \; \mbox{mb},$$ where the first error is statistical, the second accounts for all experimental systematic uncertainties and the last is related to uncertainties in the extrapolation to $|t|\rightarrow 0$. In addition, the slope of the elastic cross section at small $|t|$ is determined to be $B = 19.73 \pm 0.14 \; ({\mbox{stat.}}) \pm 0.26 \; ({\mbox{syst.}}) \; \mbox{GeV}^{-2}$.
The measured total cross section, the first systematic error accounts for all experimental uncertainties and the second error for the extrapolation t-->0.
The nuclear slope of the differential eslastic cross section at small |t|, the first systematic error accounts for all experimental uncertainties and the second error for the extrapolation t-->0.
The Optical Point dsigma/(elastic)/dt(t-->0), the total elastic cross section and the observed elastic cross section within the fiducial volume. The first systematic error accounts for all experimental uncertainties and the second error for the extrapolation t-->0.
A measurement of the total $pp$ cross section at the LHC at $\sqrt{s}=8$ TeV is presented. An integrated luminosity of $500$ $\mu$b$^{-1}$ was accumulated in a special run with high-$\beta^{\star}$ beam optics to measure the differential elastic cross section as a function of the Mandelstam momentum transfer variable $t$. The measurement is performed with the ALFA sub-detector of ATLAS. Using a fit to the differential elastic cross section in the $-t$ range from $0.014$ GeV$^2$ to $0.1$ GeV$^2$ to extrapolate $t\rightarrow 0$, the total cross section, $\sigma_{\mathrm{tot}}(pp\rightarrow X)$, is measured via the optical theorem to be: $\sigma_{\mathrm{tot}}(pp\rightarrow X) = {96.07} \; \pm 0.18 \; ({{stat.}}) \pm 0.85 \; ({{exp.}}) \pm 0.31 \; ({extr.}) \; {mb} \;,$ where the first error is statistical, the second accounts for all experimental systematic uncertainties and the last is related to uncertainties in the extrapolation $t\rightarrow 0$. In addition, the slope of the exponential function describing the elastic cross section at small $t$ is determined to be $B = 19.74 \pm 0.05 \; ({{stat.}}) \pm 0.23 \; ({{syst.}}) \; {GeV}^{-2}$.
The measured total cross section, the first systematic error accounts for all experimental uncertainties and the second error for the extrapolation t-->0.
The nuclear slope of the differential eslastic cross section at small |t|, the first systematic error accounts for all experimental uncertainties and the second error for the extrapolation t-->0.
The total elastic cross section and the observed elastic cross section within the fiducial volume.
A thin polyethylene target was exposed to the internal proton beam of the Serpukhov accelerator at 30, 50, and 70 GeV. The wide-angle recoil protons were registered by photoemulsion stacks and the differential cross sections of the elastic p−p scattering in the range of four-momentum transfer squared 0.0025≤|t|≤0.12 (GeV/c)2 were measured. The ratio of the real to the imaginary part of the forward nuclear amplitude α, the slope parameter of the diffraction peak b, and the total elastic cross section σel were found to be as follows: at 30 GeV, α=−0.183±0.051, b=10.61±0.27 (GeV/c)−2, σel=7.7±0.2 mb; at 50 GeV, α=−0.068±0.040, b=11.25±0.28 (GeV/c)−2, σel=7.0±0.2 mb; at 70 GeV, α=−0.104±0.065, b=11.21±0.40 (GeV/c)−2, σel=7.1±0.2 mb.
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The differential cross section for K ± p elastic scattering has been measured in the very low t region (0.003 < t < 0.2 GeV 2 ) in a wire chamber spectrometer experiment at 10.4 and 14 GeV/ c . The interference effect observed between the Coulomb and the nuclear interaction has been used to determine α, the ratio of real to imaginary part of the forward scattering amplitude. At 10.4 GeV/ c we measure α (K + p) = −0.21 ± 0.06 and α (K − p = 0.08 ± 0.04, and at 14 GeV/ c , α (K + p) = − 0.13 ± 0.03 and α (K − p) = 0.000 ± 0.04 in agreeement with the predictions of dispersion theory calculation.
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The logarithmic slope of the differentical cross section for K ± p elastic scattering at 10 and 14 GeV, and for π ± p and p ± p at 10GeV has been measured. Rich structure is observed in the forward slope for all processes, which is well accounted for by the properties of a peripheral exchange amplitude for the nonexotic reactions, and by a peripheral component of the diffractive amplitude as clearly seen in the exotic processes, K ± p and pp.
GRAPH OF D(SIG)/DT.
SLOPE AS A FUNCTION OF T.
Results of a high-statistics study of elastic scattering and meson resonances produced by π−p interactions at 8 GeV/c are presented. Large statistics and small systematic errors permit examination of the complete kinematic region. Total differential cross sections are given for ρ0,−, f0, g0,−, Δ±, Δ0, and N* resonances. Spin-density matrix elements and Legendre-polynomial moments are given for ρ, f, and Δ resonances. The results for ρ0 and f0 resonances are compared with the predictions of a Regge-pole-exchange model. Properties of the above resonances are compared and discussed. In particular, we present evidence that the ρ0 and f0 production mechanisms are similar. The similarity of the g0 t distribution to that of the ρ0 and f0 suggests a common production mechanism for all three resonances.
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SLOPE REFERS TO EXPONENTIAL FIT IN U.
The Fermilab hybrid 30-in. bubble-chamber spectrometer was exposed to a tagged 147-GeV/c positive beam containing π+, K+, and p. A sample of 3003 K+p, 19410 pp, and 20745 π+p interactions is used to derive σn, 〈n〉, f2cc, and 〈nc〉D for each beam particle. These values are compared to values obtained at other, mostly lower, beam momenta. The overall dependence of 〈n〉 on Ea, the available center-of-mass energy, for these three reactions as well as π−p and pp interactions has been determined.
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The results presented in this paper were obtained from a 105 000 frame exposure of the FNAL Hybrid Proportional Wire Chamber-30 inch Bubble Chamber System, in a tagged beam of 147 GeV/ c negative particles. Elastic, total and topological cross sections were obtained for both π − p and K − p interactions. Comparisons with other data, taken with various beam particles over large momentum intervals, show good agreement with KNO scaling, and similarity in the scaling behavior of σ n for the different beam particles.
THESE CROSS SECTIONS ARE NOT NORMALIZED TO ANY OTHER ABSOLUTE MEASUREMENT. THE ERRORS INCLUDE SOME SYSTEMATIC ERRORS.
THE FORWARD CROSS SECTION AGREES WELL WITH THE OPTICAL POINT FROM TOTAL CROSS SECTION MEASUREMENTS.
THESE CROSS SECTIONS ARE NOT NORMALIZED TO ANY OTHER ABSOLUTE MEASUREMENT.
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