Gamma-rays from an incomplete fusion reaction induced by 95 MeV 14N

Gamma-rays from the ${}^{159}\text{Tb}\text{(}{}^{14}\text{N}\text{, αx}\text{n}\text{)}{}^{\mathrm{169?x}}\text{Yb}$ reaction, in which non-evaporation α-particles are emitted, have been identified. Yields of E2 cascade transitions suggest that the angular momentum distribution of the entrance channel leading to this reaction is localized just above the critical angular momentum for complete fusion.     

Elastic scattering of π− from 12C at 29 MeV

We have measured the differential cross section for π^? elastically scattered from ${}^{12}\text{C at}\text{T}\text{?}{}_{\mathrm{\pi }}\text{=29}\text{MeV}$. The scattered π^? were detected with pion range telescopes. The measured angular distribution is compared with a momentum space optical potential calculation. Derived phase shifts are compared with those obtained from π⁺ data and from momentum and coordinate space calculations.     

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.     

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.     

Polarization in n-d scattering at 14.2 MeV

The angular distribution of the analyzing power in ${}^2\text{H(}\text{n}\text{,}\text{n}{}^2\text{H}$ elastic scattering has been measured at a neutron energy of 14.2 MeV in the angular range 50° to 152° c.m. Neutrons with a polarization of approximately 0.5 were obtained from the ${}^3\text{H(}\text{d}\text{n}\text{)}{}^4\text{He}$ reaction at a deuteron energy of 140 keV and lab emission angle of 82°. The ${}^3\text{H(}\text{d}\text{n}\text{)}{}^4\text{He}$ reaction was induced by vector polarized douterons obtained from a source of polarized ions. The latter was of a conventional “atomic beam” type. The results show good agreement with the data on the charge symmetric $\text{p}\text{+}\text{d}$ process at a proton energy of 14.5 MeV. Comparison is also made with the theoretical calculations of Doleschall and of Pieper and a good agreement is found.     

High resolution proton inelastic scattering from 50Cr

Resonances in the ⁵⁰Cr(p, p′γ) reaction were investigated with the TUNL high resolution system. All previously observed p-wave resonances between Ep = 2.00 and 3.03 MeV were studied. Measurement of the p' and the γ-ray angular distributions provides sufficient information to determine unambiguously the J-value of the resonance and the magnitude and relative phase of the inelastic decay amplitudes. Expressions are given for the appropriate angular distributions and for the transformation between the channel spin and the total angular momentum representation. Experimental results are presented for 24 p-wave resonances in ⁵¹Mn including decay amplitudes and relative phases for $\text{16}\text{3}\text{2}{}^{\mathrm{?}}$ resonances. Six resonances formerly assigned $\text{1}\text{2}{}^{\mathrm{?}}$ are reassigned $\text{3}\text{2}{}^{\mathrm{?}}$. Inelastic spectroscopic factors were determined for two analogue states. Proton strength functions were evaluated from both the elastic and inelastic data.     

Nuclear polarization and signs of quadrupole moments of high-spin Gd isomers

Time-differential perturbed-angular-distribution (TDPAD) experiments have been performed on polarized intermediate- and high-spin isomers ${}^{144}\text{Gd}\text{(10}{}^{\mathrm{+}}\text{)}\text{and}{}^{147}\text{Gd}\text{(}\text{13}\text{2}{}^{\mathrm{+}}\text{,}\text{27}\text{2}{}^{\mathrm{?}}\text{,}\text{49}\text{2}{}^{\mathrm{+}}\text{)}$. Excited Gd nuclei populated by $\text{(}{}^{28}\text{Si}\text{, x}\text{n}\text{)}$ reactions were polarized by the tilted-multifoil technique and implanted in a Gd single-crystal host. Observation of the subsequent electric quadrupole interaction with the known electric field gradient yielded negative values of the sign of the deformation for all isomers studied. The magnitude of the induced nuclear polarization P_I was also determined from the TDPAD data and compared to model calculations in order to deduce the average atomic angular momentum and polarization of Gd ions at v/c ～ 0.018.     

High-spin negative parity states in 19F

Levels at 7.17, 8.29, 8.96 and 9.88 MeV in ¹⁹F have been assigned spin and parity $\text{11}\text{2}{}^{\mathrm{?}}$, $\text{13}\text{2}{}^{\mathrm{?}}$, $\text{11}\text{2}{}^{\mathrm{?}}$ and $\text{11}\text{2}{}^{\mathrm{?}}$, respectively, from resonance strength and γ-ray angular distribution measurements employing the ¹⁵N(α,γ) ¹⁹F reaction. An earlier assignment of $\text{11}\text{2}{}^{\mathrm{+}}$ to the 8.96 MeV level is incorrect. The measured properties of the $\text{11}\text{2}{}^{\mathrm{?}}$ states are compared with the results of both SU (3) shell model and cluster model calculations.     

Assignment of continuous spectra by photofragment spectroscopy: C state of I2

Photofragment spectroscopy has been used to probe the C state of iodine by determining its symmetry and dissociation products. By crossing a molecular beam with a powerful pulsed laser beam in high vacuum and monitoring the arrival times of the recoiling photofragments with a mass spectrometer detector, the translational energy distribution of the photodis-sociation products is measured. From energy balance the fragment internal energy is then calculated. Our peak indicates that the C state dissociates to one excited and one ground state atom. The symmetry of the transition is determined by rotating the plane of polarization of the laser light and measuring a fragment angular distribution. The transition was found to be 1 ← 0. The results are consistent with Mulliken's assignment of the C state as 1441 $\text{1}{}_{\mathrm{u}}\text{(}{}^3\text{Σ}{}^{\mathrm{+}}\text{)}$, but inconsistent with the earlier assignment of 2332 $\text{0}{}_{\mathrm{u}}{}^{\mathrm{?}}\text{(}{}^3\text{Σ}{}^{\mathrm{+}}\text{)}$ by Mathieson and Rees.     

Analysis of (particle,xn) reactions on tantalum and gold: (II). 181Ta, 197Au(3He,xn) excitation functions and equilibrium statistical model analysis

Excitation functions for the reactions ${}^{197}\text{Au}\text{(}{}^3\text{He}\text{, x}\text{n}\text{)}{}^{\mathrm{200?x}}\text{Tl}\text{(x = 3, … 7)}$ and ${}^{181}\text{Ta}\text{(}{}^3\text{He}\text{, x}\text{n}\text{)}{}^{\mathrm{184?x}}\text{Re}\text{(x = 3, … 7)}$ were measured at bombarding energies up to 75 MeV. The data are compared to the results of an equilibrium statistical model calculation including angular momentum conservation and γ-ray competition. Satisfactory agreement was found except for the high energy tails.     

Angular correlation experiments in the reactions 2H(α, nα)p and 2H(α, pα)n and comparison with the Faddeev theory and the resonating group method

At the Hamburg Isochronous Cyclotron angular correlation experiments were carried out in the reactions ²H(α, nα)p and ²H(α, pα)n, in order to determine the tensor polarization of the ground-state resonances ${}^5\text{Li}\text{(}\text{3}\text{2}{}^{\mathrm{?}}\text{)}$ and ${}^5\text{He}\text{(}\text{3}\text{2}{}^{\mathrm{?}}\text{)}$, respectively. We find that the observables for the two mirror reactions ${}^2\text{H}\text{(α,}\text{n}\text{)}{}^5\text{Li}\text{and}{}^2\text{H}\text{(α,}\text{p}\text{)}{}^5\text{He}$ are charge-dependent. This result is interpreted as evidence for a violation of charge symmetry.In the whole phase-space region absolute break-up cross sections are generally well reproduced by the Faddeev theory. On the other hand, we find that the resonating group method which has up to now been mainly applied to two-body reactions can also provide valuable information for break-up reactions. The predictions of Hackenbroich, Schütte and coworkers are in quite good agreement with the measured tensor polarization of ⁵He and ⁵Li and the corresponding angular correlation functions.     

Measurement of the polarization parameter for antiproton-proton annihilation into charged pion and kaon pairs between 1.0 and 2.2 GeV/c

The polarization parameter P for the reactions $\text{p}\text{p}\text{→ π}{}^{\mathrm{?}}\text{π}{}^{\mathrm{+}}$ and $\text{p}\text{p}\text{→}\text{K}{}^{\mathrm{?}}\text{K}{}^{\mathrm{+}}$ has been measured over essentially the full angular range at ll laboratory momenta between 1.0 and 2.2. GeV/c, using a proton target polarized perpendicular to the scattering plane. The angles and momenta of both final state particles were determined from wire spark chambers, using the deflection caused by the polarized target magnet. Between 1000 and 5300 π^?π⁺ events, and 140 and 1300 K^?K⁺ events, were measured at each momentum. Differential cross sections for $\text{p}\text{p}\text{→ π}{}^{\mathrm{?}}\text{π}{}^{\mathrm{+}}$ were obtained. These are in excellent agreement with previous results. The polarization parameter for both channels is very close to +1 over much of the angular range. Legendre polynomial fits to the data are presented.     

Some effects of spin-orbit interaction on rotational levels and rotational line intensities in vibrationally unexcited 2A, 2E, and 2F electronic states of open-shell XY4 molecules

Rotational energy levels in vibronic ground states of ²A, ²E, and ²F electronic states of open-shell XY₄ molecules, as well as rotational line intensities for allowed transitions between such states, are discussed, including the effects of spin-orbit interaction and tetrahedral splittings. Jahn-Teller effects are assumed to be small, and are only taken into account implicitly, through their contributions to various parameters in the effective Hamiltonian. Qualitative information is obtained by considering several limiting-case coupling schemes among the electron spin angular momentum S, the electron orbital angular momentum L, and the pure rotational angular momentum R. These limiting cases are similar in spirit to Hund's coupling cases in diatomic molecules, but differ sufficiently from the latter to make detailed correspondences unhelpful. Quantitative information on rotational energy levels and line intensities is obtained numerically by diagonalizing a Hamiltonian matrix set up in a basis set characterized by uncoupled moleculefixed projections of S, L, and the total angular momentum J, and symmetrized so that all basis set functions belong to a definite species in the subgroup D_2d of the true point group T_d. Hamiltonian matrix elements are determined by ladder operator techniques. Three sample calculated spectra, corresponding to $\text{p(}{}^2\text{F}{}_2\text{)-s(}{}^2\text{A}{}_1\text{)}$, $\text{d(}{}^2\text{E)-p(}{}^2\text{F}{}_2\text{)}$, and $\text{d(}{}^2\text{F}{}_2\text{)-p(}{}^2\text{F}{}_2\text{)}$ are presented. As one might expect, when the spin-orbit constant A is set equal to zero, then both qualitative and quantitative aspects of the rotational-electronic problem in open-shell XY₄ molecules can be mapped easily onto discussions of the rotation-vibration problem from the CH₄ literature.     

Electromagnetic effects in the production of dimuons at large transverse momentum

The effects of single-photon corrections to the simple Drell-Yan mechanism $\text{(}\text{q}\text{q}\text{→ γ}{}^1\text{→ μ}{}^{\mathrm{+}}\text{μ}{}^{\mathrm{?}}\text{)}$ are studied for massive dimuons at large transverse momentum in the processes $\text{π}{}^{\mathrm{?}}\text{p}\text{→ μ}{}^{\mathrm{+}}\text{μ}{}^{\mathrm{?}}\text{X and}\text{p}\text{p}\text{→ μ}{}^{\mathrm{+}}\text{μ}{}^{\mathrm{?}}\text{X}$. It is found that single-photon emission by the muons constitutes an important correction to the effects of single-gluon emission by the quarks for very massive (M_μμ² ? m_μ²) muon pairs.Interference of the amplitude for photon emission from the muons with that for radiation from the quarks generates an asymmetry in the muon angular distribution. The forward-backward asymmetry is studied in detail as a function of pair mass and transverse momentum.     

Y1(1385) production reactions,SU(3) symmetry and vector tensor universality

This paper is devoted to a detailed study of Y¹3(1385) production processes. It is shown that the present experimental data are consistent with SU(3) symmetry, broken by the Regge trajectory splitting. Furthermore an amplitude analysis is performed using the data on the $\text{K}{}^{\mathrm{?}}\text{p}\text{→ π}{}^{\mathrm{?}}\text{Y}{}^{\mathrm{1+}}$ reaction at incident momentum of 4.25 GeV/c. This determines the double-flip amplitude, the features of which are compatible with the systematics for vector and tensor exchanges proposed by the authors.     

Comparison of the reaction pp → K0K0 at rest in hydrogen and deuterium. A test of S-state annihilation dominance

From the comparison of the frequency of antiproton annihilation at rest in two mesons in H₂ and D₂, the dominance of S-wave in $\text{p}\text{p}$ annihilation at rest is confirmed, the P-wave contribution being less than 6% at the 95% confidence level. The apparent discrepancy between the channels $\text{p}\text{p}\text{→}\text{K}{}^0\text{K}{}^0$ and $\text{p}\text{p}\text{→ππ}$ is due to the strong dependence of the annihilation dynamics from the angular momentum.     

Excitation of the deeply bound g92 neutron hole state in 117Sn by a neutron pickup reaction with 81.7 MeV 3He particles

Neutron hole states have been investigated by neutron pickup reactions on ⁹²Mo, ¹¹⁸Sn, ¹⁴⁰Ce and ²⁰⁸Pb with 81.7 MeV ³He particles. A strong effect of angular momentum mismatch has been observed to reduce the cross section for low-spin orbits. It causes the deeply bound $\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ orbit to appear in the spectrum of the α-particles from the ${}^{118}\text{Sn(τ, α)}{}^{117}$Sn reaction as a strong broad peak. It may provide a nice tool for investigating the coupling mechanism between the deeply bound holes and the core.     

The effects of finite range and channel coupling in the 32S(3He, 4He)31S reaction

Comparisons of exact finite-range (EFR) DWBA calculations and zero-range (ZR) calculations are presented for the cross sections and analysing powers of the ${}^{32}\text{S}\text{(}{}^3\text{He}\text{,}{}^4\text{He}\text{)}{}^{31}\text{S}$ reaction to the ground state ($\text{1}\text{2}{}^{\mathrm{+}}$), $\text{1.25}\text{MeV}\text{(}\text{3}\text{2}{}^{\mathrm{+}}\text{)}\text{and}\text{2.23}\text{MeV}\text{(}\text{5}\text{2}{}^{\mathrm{+}}\text{)}$ states. The data for the $\text{3}\text{2}{}^{\mathrm{+}}\text{and}\text{5}\text{2}{}^{\mathrm{+}}$ states are quite well fitted and show the characteristic j-dependence of the analysing powers. Only small differences between the EFR and ZR calculations are seen. The analysing power data for the $\text{1}\text{2}{}^{\mathrm{\pm }}$ state are poorly fitted by the EFR or ZR calculations but better agreement is obtained when the coupling to other levels is included in a coupled channel Born approximation (CCBA) calculation.     

Electrodisintegration of 3He

Double differential cross sections for electron-³He scattering leading to continuum states were measured between break-up threshold and the region of quasi-free interaction in a momentum transfer range of $\text{1}\text{fm}{}^{\mathrm{?2}}\text{< ¦}\text{q}\text{¦}{}^2\text{< 2.5}\text{fm}{}^{\mathrm{?2}}$. The cross sections for the quasi-free scattering calculated in plane-wave impulse approximation were found to be in good agreement with the experimental results for momentum transfer $\text{¦}\text{q}\text{¦ > 1.5}\text{fm}{}^{\mathrm{?1}}$.     

Investigation of high-spin states in 47Ca through double-step processes in the 48Ca(τ, α)47Ca reaction

In the ⁴⁸Ca (τ,α)⁴⁷Ca reaction at 25 MeV, some angular distributions are well reproduced by CCBA calculations, assumping double-step excitation of $\text{[}{}^{48}\text{Ca}{}^1\text{?}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}\text{]}$ states. Unambigous J^π assignments are extracted from the analysis.