Inclusive hadron-nucleus scattering at high energy

The multiple scattering series of Glauber and Matthiae for hadron-nucleus scattering is summed to a simple analytical expression. It reproduces quantitatively the main features of the experimental cross section for the reaction ${}^4\text{He}\text{+}{}^{\mathrm{A}}\text{Z →}{}^4\text{He + X}$ at 1 GeV/nucleon.     

Cross section of ion excitation in ion-ion collision

The “effective Feynman diagram” technique introduced in a previous paper is used to express the cross section of ion excitation in ion-ion collisions $\text{(A + B → A}{}^1\text{+ B)}$ in terms of the corresponding photon resonance absorption $\text{(hv + A → A}{}^1\text{)}$ and Thomson-scattering (hv + B → hv + B) cross sections. The result is checked for the process He⁺ + H(1s) → He⁺ + H(2p) with experiment and very good agreement is obtained.     

Effective cross sections and rate constants for predissociation of ClO in the earth's atmosphere

Line-by-line absorption cross sections have been computed at 220° and 300°K for the $\text{X}{}^2\text{Π}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}\text{?A}{}^2\text{Π}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$, v″ = 0 to v″ = 3 progressions of ClO. When the 300°K cross sections are convolved with a Gaussian function of 2 Å bandwidth, a maximum of 10.6 mb is observed at 277.4 nm, corresponding to the band head of the v″ = 0 to v′ = 11 transition. To calculate effective rate constants for predissociation of the $\text{A}{}^2\text{Π}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ state of ClO at altitudes ranging from 20 to 50km, the absorption cross sections were combined with estimates of the solar flux that penetrates to each altitude. The rate of predissociation is calculated to be much greater than the rate of direct photodissociation, but the former is still small compared to the loss rate of ClO caused by reactions with NO and O. Therefore, the contribution of predissociation to the destruction of ClO accounts for at most 2% of the total ClO loss. Further, calculations with a simplified chemical model indicate that the effect of ClO predissociation is to lower the rate of ozone depletion at all altitudes by a maximum of only 1%.     

Some aspects of the quark parton model

A modified Kuti-Weisskopf model which satisfies the Feynman threshold constraints is considered further. Detailed predictions for the sum of neutrino and anti-neutrino differential cross sections on nucleon (which can be readily compared with forthcoming NAL data), the shapes of the structure functions $\text{?}{}_2{}^{\mathrm{\nu p,\nu n}}$ and the ratio $\text{?}{}_2{}^{\mathrm{\nu p}}\text{/?}{}_2{}^{\mathrm{\nu n}}$, and spin-dependence of inelastic electron-nucleon scattering versus scaling variable x are delineated. We also compare in some detail the general features of our model with the “model independent” approach of Feynman for quark parton theory.     

The octupole giant resonance strength in 16O

Angular distributions for polarized proton inelastic scattering cross sections along with the analysing power for the reaction ${}^{16}\text{O}\text{(}\text{p}\text{,}\text{p}\text{′)}{}^{16}\text{O}{}^1\text{(2}{}^{\mathrm{?}}\text{, 8.88}\text{MeV}\text{)}$ at E_p=42.5, 44.0 and 49.3 MeV have been measured. A semidirect reaction analysis augments the evidence for octupole giant resonance strength in the 30 to 50 MeV energy region.     

Valence quark dominance in inelastic neutrino interactions

Scaling observed in neutrino nucleon interactions at relatively low energies and not too small , is attributed to elastic $\text{v(}\text{v}\text{)}$ scattering off three point-like, handed Zweig-Gell-Man valence quarks with low effective mass. The model predicts total inelastic cross sections all in agreement with available experiments.     

Analysis of topological cross sections in pp interactions at 22.4 GeVc

The multiplicity distribution for 11558 events in $\text{p}\text{p}$ interactions at 22.4 $\text{GeV}\text{c}$ was analyzed. The average charged multiplicity 〈n_ch〉 for inelastic events was found to be 4.69 ±0.05 and $\text{〈n}{}_{\mathrm{ch}}\text{〉}\text{D=2.04 ± 0.05}$. The early KNO scaling of normalized topological cross sections has been tested.     

Photoproduction of charged π mesons from protons and neutrons in the energy range between 250 and 790 MeV

The differential cross sections for γp→π⁺n from hydrogen and the $\text{π}{}^{\mathrm{?}}\text{π}{}^{\mathrm{+}}$ ratios from deuterium were measured at nine c.m. angles between 30° and 150° for laboratory photon energies between 260 and 800 MeV. A magnetic spectrometer with three layers of scintillation hodoscope was used to detect charged π mesons. The cross section for γn→π^?p was obtained as a product of $\text{d}\text{σ}\text{d}\text{Ω}\text{(γ}\text{p}\text{→π}{}^{\mathrm{+}}\text{n}\text{)}$ and the $\text{π}{}^{\mathrm{?}}\text{π}{}^{\mathrm{+}}$ ratio. The overall features in the cross sections of the two reactions, γp→π⁺n and γn→π^?p, and in the ratios, $\text{π}{}^{\mathrm{?}}\text{π}{}^{\mathrm{+}}$, agree with predictions by Moorhouse, Oberlack and Rosenfeld, and Metcalf and Walker. An investigation of the possible existence of an isotensor current was made and a negative result was found. In detailed balance comparison with the new results on the inverse reaction π^?p→γn, no apparent violation of time-reversal invariance was observed.     

General features of the pp interaction at 12 GeV/c

Simple inclusive cross sections for $\text{p}\text{p}$ interactions at 12 GeV/c are given. The data cover prong cross sections, V⁰ production and resonances. Separation has been made into annihilation and non-annihilation modes. Some implications of the data are discussed. It is pointed out that the ratios of cross sections for $\text{?}{}^0\text{π}{}^{\mathrm{?}}$ production are independent of incident antiproton momentum in $\text{p}\text{p}$ annihilation processes, and that data at the highest available pp energies (ISR) tend to the same value.     

Neutron total and scattering cross sections of 6Li in the low-MeV range

Neutron total cross sections of ⁶Li are measured at intervals of ? 10 keV from ≈ 0.1 to 4.8 MeV with precisions of ≈ 1 to 3 %. Differential elastic scattering cross sections are measured at intervals of ? 100 keV from 1.5 to 4.0 MeV at 10 or more scattering angles distributed between ≈ 20 and 160 deg. Differential inelastic scattering cross sections are measured at selected angles in the energy range 3.5 to 4.0 MeV. The experimental results are analyzed in terms of R-matrix theory and the model parameters used to deduce the ${}^6\text{Li(n}\text{,α)}$ cross sections. The implications of the measurements and their interpretation on the level structure of ⁷Li and the reaction mechanisms are discussed.     

On production of large transverse momentum hadrons on nuclei

It is shown that multipole pomeron cuts can lead to the inclusive cross-section dependence $\text{(}\text{ω}\text{d}{}^3\text{σ}\text{d}\text{p}{}^3\text{)A ～ A}{}^{\mathrm{\gamma (p\perp )}}$, $\text{γ(p⊥) ?}\text{4}\text{3}$ at large p⊥, due to the hard scattering of partons from different pomeron ladders.     

Proton scattering at 1 GeV

The physics of 1-GeV proton scattering on nuclei is discussed in the light of recent calculations, and compared to the Gatchina, Los Alamos, and Saclay data. The impulse approximation (including spin-orbit effects and correlations) is reviewed, and comparison is made with other theories such as the Glauber model and the low-energy optical model. This discussion is addressed to specialists as well as nonspecialists in the field. The neutron distribution is extracted from the data and a detailed comparison is made with other determinations of this distribution and with the Hartree-Fock predictions. The neutron radii are seen to be generally larger than the proton radii. Within a given shell, they increase at a much slower rate ($\text{～A}{}^{\mathrm{<mtext>1</mtext><mtext>8</mtext>}}$) than the $\text{A}{}^{\mathrm{<mtext>1</mtext><mtext>3</mtext>}}$ rule. Except possibly for ²⁰⁸Pb, they are consistent with the Hartree-Fock predictions, but not with the values obtained from Coulomb energies. The study of inelastic scattering to collective states allows the extraction of neutron transition densities, and in particular the analog B(N, L) of the electromagnetic transition rates B(E, L) one usually considers for the protons. Neutron excitations are seen to be stronger by 20 to 40 % than proton excitation, exceeding the $\text{N}\text{Z}$ prediction of the collective model. Spin effects lead only to small changes in the cross section, but to a measurable analyzing power. The unnatural parity excitations of the lowest 2^? (T = 0) state of ¹⁶O and the 1⁺ (T = 1) state of ¹²C show that the spin-spin and tensor terms of the nucleon-nucleon amplitude are sizable. Their relative magnitudes are seen to be crucial for explaining the observed cross sections.     

Channel cross sections and two-body reactions in K−p interactions at 32 GeV/c

We present a systematic investigation of channel cross sections in K^?p interactions at 32 GeV/c. The energy dependence of these cross sections is discussed. We also investigate a few non-diffractive two-body reactions. The total cross sections of the two reactions $\text{K}{}^{\mathrm{?}}\text{p}\text{→}\text{K}{}^{\mathrm{1?}}\text{(890)}\text{p}\text{and}\text{K}{}^{\mathrm{?}}\text{p}\text{→}\text{K}{}^{\mathrm{1?}}\text{(1420)}\text{p}$ have a markedly different energy behaviour. There is clear evidence for the reaction $\text{K}{}^{\mathrm{?}}\text{p}\text{→}\text{K}{}^{10}\text{(890)}\text{N}{}^0\text{(1688)}$; its differnttial cross section exhibits a sharp forward slope of 24 ± 3 GeV^?2.     

Strange particle cross sections and multiplicity distributions in 19 GeV/c proton-proton interactions

Inclusive cross sections are presented for strange-particle production in proton-proton interactions at 19 GeV/c for the pairs $\text{(}\text{K}{}^0\text{K}{}^0{}_{\mathrm{C=+1}}\text{,}\text{K}{}^0\text{Λ,}\text{K}{}^{\mathrm{+}}\text{Λ,}\text{K}{}^0\text{Σ}{}^{\mathrm{+}}\text{,}\text{K}{}^0\text{Σ}{}^{\mathrm{?}}$ and for Λ, K_s⁰, Σ⁺, Σ^? and Ξ^?. The $\text{K}\text{K}$, the KY and the total strange particle cross sections have been found to be 1.40 ± 0.10 mb, 2.69 ± 0.09 mb and 4.23 ± 0.20 mb, respectively. The charged multiplicity distributions for events with K_s⁰, Λ, $\text{(}\text{K}{}^0\text{K}{}^0\text{)}{}_{\mathrm{C=+1}}$ or K⁰ Λ are shown to follow a modified KNO curve, whereas K⁺ Λ does not. For the inclusive reactions $\text{pp}\text{→(}\text{K}{}^0\text{K}{}^0\text{)}{}_{\mathrm{C=+1}}\text{+}\text{X}{}^{\mathrm{++}}\text{,}\text{pp}\text{→}\text{K}{}^0\text{Λ +}\text{X}{}^{\mathrm{++}}\text{and pp}\text{→ Λ +}\text{X}{}^{\mathrm{++}}$, we find that the average charged multiplicity of the remainder system X⁺⁺ is the same as when X⁺⁺ is produced in other reactions with the same system energy and quantum numbers.     

The A-dependence of J/ψ-particle inclusive distributions

The differential cross sections $\text{d}\text{σ}\text{d}\text{x}$ and $\text{d}\text{σ}\text{d}\text{p}{}_{\mathrm{t}}{}^2$ of inclusive J/ψ production by 43 GeV/c π^? off Be, Cu and W nuclei have been measured. Fitting $\text{d}\text{σ}\text{d}\text{p}{}_{\mathrm{t}}{}^2\text{～ A}{}^{\mathrm{\alpha }}\text{(p}{}_{\mathrm{t}}{}^2\text{)}$ we observed the increase of α with p_t².     

Spin measurements and reaction mechanism in the inelastic scattering of 18O on 12C

The alpha-decay of states in ¹⁸O have been studied in the inelastic scattering reaction ${}^{12}\text{C}\text{(}{}^{18}\text{O}\text{,}{}^{18}\text{O}{}^1\text{→}{}^{14}\text{C}\text{-α)}$ at 82 MeV. The double differential cross sections have been analysed with a strong absorption model. A systematic dependence of emission angle on spin is observed, allowing the determination of the transferred angular momentum.     

Vector and tensor meson production in K−p interactions at 32 GeV/c

Inclusive production of vector and tensor mesons is studied in a K^?p experiment at 32 GeV/c in the MIRABELLE bubble chamber. The $\text{K}{}^{\mathrm{<mtext>1</mtext><mtext>0</mtext>}}\text{(890)}$, ?⁰ and ω cross sections are comparable, about 4 mb each. The $\text{K}{}^{\mathrm{<mtext>1</mtext><mtext>0</mtext>}}\text{(1420}$ and cross sections are also comparable, about 1 mb each. The $\text{K}{}^{\mathrm{<mtext>1</mtext><mtext>o</mtext><mtext>?</mtext><mtext>+</mtext>}}$(890), Φ, $\text{K}{}^{\mathrm{<mtext>1</mtext><mtext>o</mtext><mtext>?</mtext><mtext>?</mtext>}}$(1420) and f cross sections beam fragmentation; ? production is almost forward-backward symmetric in the c.m.s. The p_T production slopes of $\text{K}{}^{\mathrm{<mtext>1</mtext><mtext>o</mtext><mtext>?</mtext><mtext>?</mtext>}}\text{(890)}$ and ? are similar, the Φ slope is shallower. Vector and tensor mesons alone are responsible for ?50% (?60%) of final-state pions     

The (α, α), (α, α′) and (α, 3He) reactions on 12C at 139 MeV

The nucleus ¹²C was bombarded with 139 MeV α-particles to study the characteristics of the elastic, inelastic, and (α, ³He) reactions. An optical model analysis of the elastic data yielded a unique family of Woods-Saxon potential parameters with central real well depth V ≈ 108 MeV, and volume integral $\text{J}\text{4A}\text{≈ 353}\text{MeV}\text{·}\text{fm}{}^3$. By comparing the present results with those of other studies above 100 MeV, we find that the real part of the α-nucleus interaction decreases with increasing energy; the fractional decrease with energy is roughly one-half that observed for proton potentials. Using the optical potential parameters derived from the elastic scattering, first-order DWBA calculations with complex first-derivative form factors reproduced the inelastic scattering data to the 4.44 MeV (2⁺) and 9.64 MeV (3^?) states of ¹²C. For the 0⁺ state at 7.65 MeV it was necessary to employ a real, second-derivative form factor to fit the data. The deformation lengths β_lR_m and deformations β_l obtained in this and other experiments are summarized and compared. DWBA calculations using microscopic model form factors were also performed for the 2⁺ and 3^? states using the wave functions of Gillet and Vinh Mau. These reproduced the shapes and relative magnitudes of the differential cross sections. We also fit the shape of the 0⁺ differential cross section using a microscopic form factor which contains a node, which is similar to that occurring in the collective model second-derivative form factor. In the ($\text{α,}{}^3\text{He}$) reaction the differential cross sections to the ground state ($\text{1}\text{2}{}^{\mathrm{?}}$) and the 3.85 MeV ($\text{5}\text{2}{}^{\mathrm{+}}$) state in ¹³C could not be reproduced by zero-range local DWBA stripping calculations; it was necessary to employ finite-range and non-local corrections in the local-energy approximation. This DWBA analysis is notable in that unambiguous optical potentials were available for both entrance and exit channels. The ground state spectroscopic factor is in agreement with the prediction of Cohen and Kurath, while the relative spectroscopic factors agree fairly well with the rather few existing measurements of this kind.