Elastic electron scattering at 30–80 MeV from 142,146,150Nd

The elastic electron scattering cross sections for ${}^{\mathrm{142,146,150}}\text{Nd}$ have been measured at momentum transfers between 0.2 and 0.8 fm^?1. The results do not support the anomalously small skin thickness values obtained in a previous low-energy electron scattering experiment.     

Magnetic elastic electron scattering from 3Be and 13C

Elastic scattering through 180° from ⁹Be, ¹²C and ¹³C targets has been observed for electrons of 35 to 90 MeV. Magnetic scattering cross sections for ⁹Be and ¹³C have been obtained by subtracting charge scattering as deduced from the scattering from the spin-zero nucleus ¹²C. Theoretical shell model predictions for the magnetic cross sections are derived for (1s)⁴(1p)^A?4 configurations and various coupling schemes. Both harmonic oscillator and Woods-Saxon radial wave functions are used. A comparison of our results with magnetic cross sections calculated in DWBA yields magnetic rms radii $\text{〈r}{}^2\text{〉}{}_{\mathrm{<mtext>M</mtext>}}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 3.2 ± 0.3}\text{fm}$ and $\text{〈r}{}^2\text{〉}{}_{\mathrm{<mtext>M</mtext>}}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 3.3 ± 0.3}\text{fm}$ for ⁹Be and ¹³C. For ¹³C a combined flt to our low-q data and to earlier high-q data, yields $\text{〈r}{}^2\text{〉}{}_{\mathrm{<mtext>M</mtext>}}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 3.4 ± 0.1}\text{fm}$ and a strong preference for intermediate coupling (IC) wave functions. Magnetic dipole scattering from ⁹Be is also close to the IC prediction, as deduced from a fit to our data and earlier high-q data. The fitted value of the octupole moment $\text{Ω = 5±1 μ}{}_{\mathrm{<mtext>N</mtext><mtext>fm</mtext>}}{}^1$ can only be explained by a deformation of the average nuclear potential. The radial size $\text{〈r}{}^2\text{〉}{}_{\mathrm{<mtext>1</mtext><mtext>p</mtext>}}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 2.85 ± 0.05}\text{fm}$ for the 1p radial wave function is in agreement with both the ⁹Be and ¹³C data.     

Absolute electron-proton cross sections at low momentum transfer measured with a high pressure gas target system

Absolute differential cross sections for elastic electron-proton scattering have been measured in a four-momentum transfer range up to 1.4 fm^?2. Using a high pressure gas target system, we have obtained highly accurate data with a small normalization error of 0.5%. The electromagnetic form factors G_E and G_M have been extracted and the rms charge radius has been determined to be $\text{〈r}{}^2{}_{\mathrm{<mtext>E</mtext>}}\text{〉}{}_{\mathrm{<mtext>p</mtext>}}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 0.862±0.012}\text{fm}$. The shape of the isovector spectral function near threshold shows a significant non-resonant contribution of the two-pion state. This enhancement is so strong that the derivative at q² = 0 differs considerably from the usual vector meson dominance model value. This result is in good agreement with theoretical predictions.     

Pion photoproduction on 3He at and above the 3-3 resonance

The differential cross section for the ${}^3\text{He}\text{(γ, π}{}^{\mathrm{+}}\text{)}{}^3\text{H}$ reaction has been measured at fixed values of q² in the region of the first resonance, and at fixed θ_π versus q² up to 13 fm^?2. The observed shift of the resonance towards lower energies, and the absence of a minimum near 11.6 fm^?2 might be explained by recent theoretical calculations.     

Electron scattering from the 3.65 MeV (0+, T = 1) state in 6Li at high momentum transfer

The form factor ofthe 3.56MeV(0⁺, T = 1) state of ⁶Li has been measured for momentum transfers q = 1.0–3.0 fm^?1, and the $\text{2.18}\text{MeV}\text{(3}{}^{\mathrm{+}}\text{, T = 0)}$ and $\text{5.37}\text{MeV}\text{(2}{}^{\mathrm{+}}\text{, T = 1)}$ states have been measured up to q = 2.5 fm^?1. The 3.56 MeV form factor is analysed in terms of a phenomenological shell model with l = i valence nucleons. The radial wave functions are found to have a greater radial distribution than given by the harmonic oscillator, more closely resembling Woods-Saxon functions. The M1 form factor is found to decrease at high momentum transfer somewhat more slowly than the models predict. A technique for determining the Mλ transition current density based on the Fourier-Bessel analysis is developed and applied to the M1 transition. The M1 transition current density is obtained within a moderate error band and compared with the harmonic oscillator and Woods-Saxon densities. The M1 radiative width is 8.18 ± 0.25 eV, in agreement with previous measurements.     

Elastic scattering of π±p, K±p,pp ANDprmpp AT 39 AND 44.5 GeV/c

The differential cross sections for elastic $\text{π}{}^{\mathrm{?}}\text{p, K}{}^{\mathrm{?}}\text{p}\text{,}\text{p}\text{p and}\text{π}{}^{\mathrm{+}}\text{p, pp}$ scattering at 39 and 44.5 GeV/c, respectively, have been measured in the interval of momentum transfer squared 0.15 ≤ ovbt| ≤ 2 (GeV/c)².     

Elastic electron scattering from the magnetization distribution of 27Al

Cross sections have been measured for the scattering of electrons through 180° from Mg, Al and Si targets in the energy range 35 to 95 MeV. Scattering from the magnetization distribution of ²⁷Al is observed as the difference of the scattering from ²⁷Al and from the neighbouring doubly even nuclei Mg and Si. Corrections have been applied for differences in instrumental effects and in rms charge radii. Theoretical magnetic cross sections have been computed with a single-particle wave function and with a shell-model wave function involving configuration mixing. If the distorted-wave Born approximation is used, good agreement with experiment is obtained. In both cases the best fit to the data yields a value of the oscillator range parameter b = 1.71 ± 0.06 fm. Using the q-dependence of the single-particle model a value $\text{Ω = 18.7 ± 3.5 μ}{}_{\mathrm{<mtext>N</mtext>}}\text{·}\text{fm}{}^2$ for the magnetic octupole moment of ²⁷Al is found. The present low-energy (E < 100 MeV) data are in good agreement with the results obtained from the scattering of high-energy (E = 500 MeV) electrons from ²⁷Al through “normal” angles.     

Integrated quasi-elastic neutron scattering intensity of hydrogen in niobium

The integrated quasi-elastic neutron scattering intensity of NbH_0.13 has been measured at 235°C over a large momentum transfer range $\text{(0.6 < K < 7}\text{A}\text{?}{}^{-1}\text{)}$. In the high temperaturephase a deviation from a simple Debye-Waller factor governed intensity dependence has been observed.     

Electron-positron pair production as a probe of chiral symmetry in a hot QCD plasma

Chiral symmetry in the high-temperature plasma phase of QCD is consistent with at least three qualitatively different quark dispersion relations. The rate for $\text{q}\text{q}\text{→}\text{e}{}^{\mathrm{+}}\text{e}{}^{\mathrm{?}}$, with zero total momentum of the e⁺e^? pair in the plasma rest frame is direct measure of the quark dispersion relation. For the three plausible dispersion relations the rates differ by orders of magnitude when the e⁺e^? invariant mass M < 2T.     

Off-diagonal generalized vector dominance and inelastic ep scattering

By also taking into account off-diagonal contributions to the virtual forward Compton amplitude, scaling in ep scattering is obtained from scaling of the total cross section for e⁺e^? annihilation into hadrons. The parameter which sets the scale for the q² dependence in ep scattering is calculated to be $\text{m}{}^2\text{? 0.61 m}{}_{\mathrm{?}}{}^2\text{? 0.36}\text{GeV}{}^2$.     

Broken conformal symmetry and hadronic scaling

High energy, large momentum transfer hadronic reactions are studied in the framework of broken conformal symmetry. Hadrons lie on almost linear Regge trajectories. Inclusive cross section scale as $\text{～s}{}^{\mathrm{?2}}\text{(}\text{q}{}^2{}_{\mathrm{<mtext>T</mtext>}}\text{s)}{}^{\mathrm{?4}}$. Large rates of heavy particle production are predicted.     

Small momentum transfer measurements of S(k) in 4He at T = 4.27 K as function of density

We report the first measurements of S(k) in ⁴He at a fixed temperature of T = 4.27 K for 126 < p < 164 kg/m³ for the momentum transfer range $\text{0.18 < k < 1.03}\text{A}\text{?}{}^{\mathrm{?1}}$. Our results are consistent with expectations at zero momentum transfer based on thermodynamics.     

Measurement of elastic scattering in antiproton-proton collisions at 52.8 GeV centre-of-mass energy

We measured the differential cross section for p?p and pp elastic scattering in the momentum-transfer range 0.01 <|t| < 1.0 GeV² at the CERN Intersecting Storage Rings with center-of-mass energy $\text{s}\text{= 52.8}\text{GeV}$. Fitting the differential cross section with an exponential [Aexp (bt)], we found $\text{b}\text{p}\text{p = 13.92 ± 0.59}\text{GeV}{}^{\mathrm{?2}}$ for |t| < 0.05 GeV², whilst for |t| > 0.09 GeV², $\text{b}\text{p}\text{p = 10.68 ± 0.26}\text{GeV}{}^{\mathrm{?2}}$. Using the optical theorem, we obtained for the total cross section $\text{σ}{}_{\mathrm{<mtext>tot</mtext>}}\text{(}\text{p}\text{p)= 44.86 ± 0.78}\text{mb}$ and, by integrating the differential cross section, we obtained for the total elastic cross section $\text{σ}{}_{\mathrm{<mtext>el</mtext>}}\text{(}\text{p}\text{p) = 7.89 ± 0.28}\text{mb}$. Calculations of σ_tot combining elastic-rate and total-rate measurements are also given. All of these measurements were also performed for pp scattering at the same energy, and the results for both reactions are compared.     

Results on the production cross sections π−p → neutrals and π− p→ χ↳2γ0n at 3.8, 6, 8 and 12 GeV/c

The ratio between the cross sections for the reactions $\text{π}{}^{\mathrm{?}}\text{p→}\text{χ}\text{?}{}_{\mathrm{2\gamma }}{}^0\text{n}$ and π^?p → η_→2γ n has been measured to be (2.4 ± 0.9) × 10^?2, (2.1 ± 0.6) × 10^?2 and (2.8 ± 1.3) × 10^?2 at 3.8,6,8 and 12 GeV/c incident momentum respectively.At the same momenta the cross section for π^t- p → neutrals is (1.48 ± 0.09) mb, (0.86 ± 0.05) mb, (0.64 ± 0.04) mb and (0.42±0.03) mb.     

Accurate determination of the 17O16O + n coupling constant and spectroscopic factor

We have measured ¹⁶O¹⁷O elastic cross sections at 22 MeV between 65°–140° to ± 1 %. The observed oscillatory interference between Coulomb scattering and the neutron transfer process is analyzed using exact finite-range DWBA. A model-independent value of $\text{C}\text{?}{}^2\text{= 0.82 ± 0.07}$ is obtained for the coupling constant of the 1d_{$\text{5}\text{2}$} neutron in ¹⁷O. We also present an analysis of data on magnetic electron scattering from ¹⁷O, which yields precise information on the magnitude and the radial shape of the $\text{1}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}$ neutron bound-state wave function. With this we relate the coupling constant to the spectroscopic factor and find S = 1.04 ± 0.11. We show that the magnetic electron scattering data alone yield S = 1.04 ± 0.10. Combining these results with earlier work we recommend $\text{C}\text{?}{}^2\text{= 0.79 ± 0.04}$ and S = 1.03 ± 0.07 as best values. This spectroscopic strength corresponds to (91 ± 7) % of the full single-particle value.     

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.     

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.     

K−p → Λ0 or Σ0 + vector meson at 3.1 −3.6 GeV/c

We present data on the five final states $\text{Λω, Λφ, Λ?}{}^0\text{, Σ}{}^0\text{?}\text{and}\text{Σ}{}^0\text{?}{}^0$ produced in 3.1–3.6 GeV/c K^?p interactions. These data are from a bubble chamber experiment with 18 events/μb. For all reactions the data consist of the overall and differetial cross sections, and the hyperon polarisation and the vector meson's density matrix elements as a function of momentum transfer. For Λω and Λ?, an almost complete amplitude analysis is performed in several regions of momentum transfer. The data are examined from the point of view of various exchange models.     

Spin assignments in 59Ni from the 58Ni(d, p)59Ni reaction

Angular distributions of the vector analyzing power and the absolute cross section were measured for the ⁵⁸Ni(d, p)⁵⁹Ni reaction at a deuteron energy of 10 MeV. The observed j-dependence of the vector analyzing power allowed unambiguous spin assignments for the following states in ⁵⁹Ni with excitation energies in $\text{MeV}\text{: 0.0,}\text{3}\text{2}{}^{\mathrm{?}}\text{; 0.341,}\text{5}\text{2}{}^{\mathrm{?}}$; $\text{0.465,}\text{1}\text{2}{}^{\mathrm{?}}\text{; 0.879,}\text{3}\text{2}{}^{\mathrm{?}}$; $\text{1.303,}\text{1}\text{2}{}^{\mathrm{?}}\text{; 1.686,}\text{5}\text{2}{}^{\mathrm{?}}\text{; 3.454,}\text{3}\text{2}{}^{\mathrm{?}}\text{; 3.858,}\text{3}\text{2}{}^{\mathrm{?}}\text{; 4.495,}\text{5}\text{2}{}^{\mathrm{+}}$. The data are well reproduced by DWBA calculations employing deuteron and proton optical model parameters obtained from analyses of elastic scattering cross sections and polarizations. A tentative spin assignment of $\text{9}\text{2}{}^{\mathrm{+}}$ is made for the level at 3.061 MeV. A $\text{5}\text{2}{}^{\mathrm{+}}$ assignment to the level at 3.538 MeV is suggested on the basis of the empirical behavior of the j-dependence of the vector analyzing power for l = 2 transitions. Measurements of the vector analyzing power for the four low-lying ⁵⁹Ni states formed by l = 1 transfer were made for angles from 2.5° to 15° using a magnetic spectrograph. A very strong j-dependence was observed for these far-forward-angle measurements in agreement with DWBA predictions.