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.     

Spin determinations from the 58Ni(d→, α)56Co reaction at 80 MeV

Vector analyzing power angular distributions for the ${}^{58}\text{Ni}\text{(}\text{d}\text{→}\text{,a)}{}^{56}\text{Co}$ reaction have been measured at 80 MeV bombarding energy. They exhibit large differences between the possible transferred total angular momenta J=L+1, J=L and J=L ? 1, thus allowing unique spin determinations of the levels in the residual nucleus ⁵⁶Co. This has led to new spin assignments for the following high-spin states in ${}^{56}\text{Co}\text{: 3.54}\text{MeV}\text{, 7}{}^{\mathrm{+}}\text{; 4.44}\text{MeV}\text{, 7}{}^{\mathrm{+}}\text{; 5.14}\text{MeV}\text{, 5}{}^{\mathrm{+}}$.     

The decay process 11ΛB → π− + 11C

The branching ratios are calculated for ¹¹_ΛB decay to the ¹¹C ground and excited states below 8 MeV for two possible spin values of ¹¹_ΛB. It is found that the decay rate to the ¹¹C^★ state at E^★ = 6.48 MeV is comparable in magnitude to that leading to the ¹¹C ground state if $\text{J(}{}^{11}{}_{\mathrm{\Lambda }}\text{B}\text{) =}\text{5}\text{2}$ is assumed. This result, unlike the branching ratios calculated for the $\text{J(}{}^{11}{}_{\mathrm{\Lambda }}\text{B}\text{) =}\text{7}\text{2}$ case, is in accord with experiment and lends support to the assumption that $\text{J =}\text{5}\text{2}$ holds for ¹¹_ΛB. The necessity of the reinterpretation of some of the so-called ¹³_ΛC events in terms of ${}^{11}{}_{\mathrm{\Lambda }}\text{B}\text{→ π}{}^{\mathrm{?}}\text{+}{}^{11}\text{C}{}^1$ is indicated.     

Excitation function of giant resonances as doorway states in the 12C(p, p′)12C1 reaction between 19 and 23 MeV

Differential cross section and analyzing power angular distributions for the elastic scattering and inelastic scattering to the 2⁺ state at 4.44 MeV and the 1⁺ state at 12.7 MeV have been measured at incident proton energies varying from 19.15 to 23.34 MeV in 200 keV steps. Elastic scattering data are analyzed using an averaged optical model. Coupled-channel calculations reproduce roughly the 2⁺ data. The rapid variation of the data concerning the 1⁺ state is explained by virtual excitation of giant resonances. For each value of the incident energy, the coupling strength for each resonance is found by fitting the experimental angular distributions. The analysis assuming a weak coupling in the compound system gave a satisfactory fit to the cross section but a poor reproduction of the analyzing power. The assumption of a strong coupling in the ¹³N system allowed a good fit of all data. The angular distributions are dominated by the E1 resonance, whose $\text{1}\text{2}{}^{\mathrm{+}}$ component exhausting more than 37 % of the energy weighted sum rule, explains the isotropy of the cross section below 22 MeV. A $\text{7}\text{2}{}^{\mathrm{+}}$ resonance (15 % EWSR) is located at 19.9 MeV. The $\text{5}\text{2}{}^{\mathrm{?}}$ resonance with its maxima at 20.2 and 21.4 MeV, exhausts about 18 % of the sum rule, which is in good agreement with the results of previous works.     

The 7Li(d, n0)8Be reaction with polarized 800 keV deuterons

The analysing power of the ${}^7\text{Li}\text{(}\text{d}\text{, n}{}_0\text{)}{}^8\text{Be}$ reaction for vector and tensor polarization of an 800 keV deuteron beam, as well as the relative cross section for the unpolarized beam were measured at 7 to 9 angles between 0° and 160°, using a thick target. Analysis in terms of (l, s, J^π) matrix elements shows that two intermediate states with $\text{J}{}^{\mathrm{\pi }}\text{=}\text{3}\text{2}{}^{\mathrm{+}}$ and $\text{J}{}^{\mathrm{\pi }}\text{=}\text{5}\text{2}{}^{\mathrm{?}}$ present, strongly interfering with each other. Assignments to known ⁹Be levels and to threshold resonances as suggested by Hackenbroich and Seligman are briefly discussed. The magnitude of the vector analysing power makes the reaction interesting as a monitor for the vector polarization of low-energy deuteron beams.     

Two-quasiproton states in 168Er studied by the 169Tm(t, α)168Er reaction

The ${}^{169}\text{Tm}\text{(}\text{t}\text{, α)}{}^{168}\text{Er}$ reaction has been studied using 17 MeV polarized tritons from the Los Alamos National Laboratory tandem Van de Graaff accelerator. The α-spectra were analyzed with a Q3D magnetic spectrometer. The overall energy resolution was typically ~ 15 keV (FHWM) and angular distributions of cross sections and analyzing powers were obtained for levels up to ~ 2.7 MeV. The fact that spins and parities for all levels up to ? 2 MeV were previously known from an extensive series of (n, γ) studies made it possible to determine specific two-quasiproton structures for many bands from the present results. The K^π = 2⁺ γ-vibrational band was found to have a large $\text{3}\text{2}{}^{\mathrm{+}}\text{[411]}{}_{\mathrm{<mtext>p</mtext>}}\text{+}\text{1}\text{2}{}^{\mathrm{+}}\text{[411]}{}_{\mathrm{<mtext>p</mtext>}}$ admixture, consistent with the predicted microscopic composition of this phonon, but no $\text{5}\text{2}\text{[413]}{}_{\mathrm{<mtext>p</mtext>}}\text{?}\text{1}\text{2}{}^{\mathrm{+}}\text{[411]}{}_{\mathrm{<mtext>p</mtext>}}$ component was observed. The K^π = 0₄⁺ band at 1833 keV has ～ 25% of the $\text{1}\text{2}{}^{\mathrm{+}}\text{[411]}{}_{\mathrm{<mtext>p</mtext>}}\text{?}\text{1}\text{2}{}^{\mathrm{+}}\text{[411]}{}_{\mathrm{<mtext>p</mtext>}}$ two-quasiproton strength. This is in excellent agreement with the Soloviev model but is inconsistent with the interacting boson model, in which the K^π = 0₄⁺ band is composed almost completely of multiphonon configurations that should not be populated in a single-nucleon transfer reaction. The $\text{K}{}^{\mathrm{\pi }}\text{= 4}{}^{\mathrm{?}}\text{,}\text{7}\text{2}{}^{\mathrm{?}}\text{[523]}{}_{\mathrm{<mtext>p</mtext>}}\text{+}\text{1}\text{2}{}^{\mathrm{+}}\text{[411]}{}_{\mathrm{<mtext>p</mtext>}}$ two-quasiproton and the $\text{K}{}^{\mathrm{\pi }}\text{= 4}{}^{\mathrm{?}}\text{,}\text{7}\text{2}{}^{\mathrm{+}}\text{[633]}{}_{\mathrm{<mtext>n</mtext>}}\text{+}\text{1}\text{2}{}^{\mathrm{?}}\text{[521]}{}_{\mathrm{<mtext>n</mtext>}}$ two-quasineutron states are mixed strongly with each other, but the two K^π = 3^? bands composed of antiparallel couplings of the same particles are not. A good qualitative explanation of this mixing pattern is provided in terms of the effective neutron-proton interaction.     

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.     

The reactions K−p → K1− + nucleon at 3.13 and 3.3 GeV/c

Results are presented of a 12 event/μb bubble-chamber experiment; the reactions discussed in detail are $\text{K}{}^{\mathrm{?}}\text{p}\text{→}\text{K}{}^1\text{(890)}{}^{\mathrm{?}}\text{p, K}{}^1\text{(1420)}{}^{\mathrm{?}}\text{p and K}{}^1\text{(890)}{}^{\mathrm{?}}\text{Δ}{}^{\mathrm{+}}$.The K¹ (890)^?p channel is dominated by the forward peak. The suggestion of flattering at cos θ = 1 is more pronounced in $\text{(?}{}_{11}\text{+ ?}{}_{\mathrm{1?1}}\text{)}\text{d}\text{σ}\text{d}\text{t}$; which is mainly natural-parity exchange. Pseudoscalar exchange contributes to $\text{?}{}_{00}{}^{\mathrm{J}}\text{d}\text{σ}\text{d}\text{t}$; this is more sharply peaked in t. The value of $\text{(?}{}_{11}\text{? ?}{}_{\mathrm{1?1}}\text{)}\text{d}\text{σ}\text{d}\text{t}$ is somewhat larger than the upper limit from the dominant natural-parity exchange. There is significant structure in $\text{?}{}_{00}{}^{\mathrm{H}}\text{d}\text{σ}\text{d}\text{t}\text{at}\text{t ≈ ?0.6 (}\text{GeV}\text{/c)}{}^2$.The K¹ (1420)^?p channel is much more pronounced at 3.3 GeV/c than at 3.13 GeV/c, but is not markedly peripheral. The width of the K¹ (1420) in the 3.3 GeV/c data is 42 ± 12 MeV/c².The cross section for $\text{K}{}^{\mathrm{1?}}\text{Δ}{}^{\mathrm{+}}$ agrees with that expected from $\text{K}{}^{\mathrm{+}}\text{p}\text{→}\text{K}{}^1\text{Δ}$, assuming a single t-channel exchange. Our measured density matrix elements are consistent with a strong pseudoscalar exchange.     

Evidence for new meson resonances from the reaction pp → K−K+

The differential cross sections for $\text{p}\text{p}\text{→}\text{K}{}^{\mathrm{?}}\text{K}{}^{\mathrm{+}}$ provide new evidence for mesons with masses between 2.1 and 2.5 GeV/c². The zeros of the cross sections suggest the existence of J^P = 3^? states with both I = 1 and I = 0 at masses between 2.1 and 2.18 GeV/c². The results also support a J^P = 4⁺ state near 2.34 GeV and are consistent with 5^? states in both I = 1 and I = 0 close to 2.5 GeV. This analysis confirms the I = 1 3^?, 5^? and I = 0 4⁺ states seen previously in $\text{p}\text{p}\text{→ π}{}^{\mathrm{?}}\text{π}{}^{\mathrm{+}}$ and is in agreement with the existing data for the non-annihilation processes.     

The second 132+ state in 19F

A cryogenically pumped gas target has been used to study resonances in the ¹⁵N(α, γ)¹⁹F reaction for E_α = 5.1 to 8.6 Mev. Gamma-ray intensity and angular distribution measurements for a resonance at E_α = 8.105 Mev, corresponding to a state at 10.411 MeV in ¹⁹F, restrict the spin and parity of the state to $\text{11}\text{2}{}^{\mathrm{+}}$ or $\text{13}\text{2}{}^{\mathrm{+}}$. Comparison with shell model calculations indicate that the state is a strong candidate for the second $\text{13}\text{2}{}^{\mathrm{+}}$ (2s, 1d)³ level in ¹⁹F.     

The decay processes Λ8Li → π− + 8Be1 (∼ 17 MeV)

The branching ratio is calculated for _Λ⁸Li decay to the (2⁺) ⁸Be¹ states near 17 MeV, using intermediate coupling wave functions for _Λ⁸Li and for the relevant ⁸Be¹ states. It is pointed out that this ratio is sensitive primarily to a mixing angle ? in the _Λ⁸Li wave function. Within one standard deviation, the data allow two ranges (+0.05 to +0.25 rad and +1.10 to +1.25 rad) for the value of ?. The further requirement that there also be acceptable agreement between the angular distribution expected for the subsequent ${}^8\text{Be}{}^1\text{(? 17}\text{MeV → 2}{}^4\text{He}$ decay and the data, shifts these allowed ranges for ?, to (+0.13 to 0.40) rad and (+0.9 to +1.2) rad. It is predicted that the dominant transition should be to ⁸Be¹ (16.6 MeV), as is observed to be the case, rather than to ⁸Be¹ (16.9 MeV). The interpretation of these values for ? is discussed in some detail and their implications for intermediate coupling shell-model calculations of Λ-hypernuclear wave functions are considered.     

Medium-spin levels and the character of the 20.4 ns 132+ isomer in 145Gd

Levels of the N = 81 nucleus ¹⁴⁵Gd have been investigated by in-beam γ-ray and conversion electron spectroscopy with the ¹⁴⁴Sm(³He, 2n) reaction. Fourteen new low- and medium-spin states between 1.0 and 2.4 MeV excitation, the known yrast levels up to spin $\text{21}\text{2}{}^{\mathrm{+}}$, five other high-spin non-yrast states and a new 20.4 ns $\text{13}\text{2}$ isomer at 2200.2 keV in ¹⁴⁵Gd have been observed. The isomer decays via a fast 927.3 keV E3 transition with B(E3) = 48 ± 7 W.u. Another weaker decay branch is a mixed, strongly hindered E1 + M2 + E3 transition to the $\text{v}\text{h}{}^{\mathrm{?1}}{}_{\mathrm{<mtext>11</mtext><mtext>2</mtext>}}$ state. We propose an octupole $\text{v}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}\text{j}{}^{\mathrm{?2}}\text{× 3}{}^{\mathrm{?}}$ main configuration for the isomer, analogous to the 997 keV $\text{13}\text{2}{}^{\mathrm{+}}$ isomer in ¹⁴⁷Gd. The levels of ¹⁴⁵Gd are discussed on the basis of the spherical shell model.     

The reaction pp→pπ−π+p at 25 and 40 GeV/c

The reaction $\text{p}\text{p}\text{→}\text{p}\text{π}{}^{\mathrm{?}}\text{π}{}^{\mathrm{+}}\text{p}$ has been studied at 25 and 40 GeV/c at the Serpukhov proton synchroton using the CERN-IHEP spectrometer. The differential cross section has been determined as a function of four-momentum transfer to the proton (0.05–0.30 (GeV/c)²) and $\text{p}\text{ππ}$ mass (up to 2.2 and 2.6 GeV/c²). At both energies there is a broad low-mass maximum with an enhancement at 1.6–1.8 GeV/c². The cross section in a given mass band falls rapidly with |t|, with an exponential slope that decreases with increasing mass. In both the background and the 1.7 GeV/c² peak there is a strong $\text{Δ}{}^{\mathrm{??}}\text{π}{}^{\mathrm{+}}$ component. Possible spin-parity (J^P) contributions to it are discussed. Throughout the range 1.5–2.2 GeV there is at least one state of $\text{J ?}\text{3}\text{2}$ and there is interference between states of opposite P, |ΔJ| ? 1. At the peak there is a $\text{J ?}\text{5}\text{2}$ component. There are striking parallels between this reaction and the boson reactions π^?p→π^?π^?π⁺p and K^? → K^?π^?π⁺p.     

The (1f72)2 states in 34S

A distorted wave analysis of the ³²S(t,p) ³⁴S reaction reveals that the 0⁺ state at 5.86 MeV, the 2⁺ state at 7.80 MeV and the 4⁺ state at 8.42 MeV are the principal components of the $\text{(1}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}^2$, T = 1 multiplet.     

Laser magnetic resonance spectrum of BrO (2Π12 ← 2Π32)

Magnetic dipole transitions between the ${}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ and ${}^2\text{Π}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ components of the ground electronic state of BrO have been detected using the technique of laser magnetic resonance on three CO₂ laser lines between 964 and 970 cm^?1. This is the first direct observation of the ${}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ state in BrO. The spin-orbit splitting parameter, A, is determined to be ?967.9831(2) cm^?1 for ⁷⁹Br¹⁶O and ?967.9981(2) cm^?1 for ⁸¹Br¹⁶O. Accurate values for the rotational constant $\text{B}{}^{\mathrm{<mtext>eff</mtext>}}\text{(}{}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{)}$, the hyperfine parameters ($\text{b}{}_{\mathrm{F}}\text{+}\text{2c}\text{3}$) and d, the Λ-doubling parameter p, and the Zeeman parameter g| are also determined from an analysis of the measured spectra.     

Analysis of the Ã1A″ ← X̃1A′ electronic transition in thiocarbonyl chlorofluoride

The visible absorption spectrum of thiocarbonyl chlorofluoride, ClFCS, in the region 5000 to 3000 Å has been observed under conditions of high resolution in the vapor phase and has been assigned to the $\text{A}\text{?}{}^1\text{A″(nπ}{}^1\text{) ←}\text{X}\text{?}{}^1\text{A′}$ and $\text{a}\text{?}{}^8\text{A″(n, π}{}^1\text{) ←}\text{X}\text{?}{}^1\text{A′}$ electronic transitions. All six fundamental modes have been assigned for both the upper and lower singlet electronic states. From the observed splittings of the even-odd quanta of ν₆′ in the spectrum the barrier to inversion in the $\text{A}\text{?}{}^1\text{A″}$ state has been evaluated to be 1556.0 ± 45 cm^?1.     

The 5T2g → 5Eg absorption in MgO: Fe2+

At helium temperatures two sharp lines at 9350 and 9510 cm^?1 have been observed for the first tune on the low-energy side of the broad double-peaked absorption corresponding to the ${}^5\text{T}{}_{\mathrm{2g}}\text{→}{}^5\text{E}{}_{\mathrm{g}}$ transition in Fe²⁺ at the octahedral site in MgO. The lower energy line has a half width of 4 cm^?1; Zeeman measurements show that it is of magnetic dipole origin. The Zeeman spectra are consistent with those expected for a pure electronic transition from the (⁵T_2g)T_2g ground state to the ⁵E_g excited state. The second line, with a halfwidth of ~ 35 cm^?1, a vibrational sideband.     

Measurement of the g-factor and mean lifetime of the 13C(52+1) state

The g-factor and mean life of the $\text{5}\text{2}{}^{\mathrm{+}}{}_1$ state at 3.85 MeV in ¹³C have been determined by a recoil-into-vacuum plunger measurement. The state was populated by the ²H(¹²C, p) reaction at E = 15.0 MeV. The analysis of the time-differential deorientation effect on the p-γ angular correlation leads to a g-factor of $\text{¦g¦ = 0.558 ± 0.015}$. For the mean lifetime a value of τ = 12.2 ± 0.4ps is obtained.     

An upper limit to the cross section for the reaction νμe−→νμe− at SPS energies

Candidates for the purely leptonic process $\text{ν}{}_{\mathrm{\mu }}\text{e}{}^{\mathrm{?}}\text{→}\text{ν}{}_{\mathrm{\mu }}\text{e}{}^{\mathrm{?}}$ have been searched for in the bubble chamber Gargamelle exposed to the CERN-SPS antineutrino wide-band beam. No single e^?, of energy greater than 1 GeV, was found in a total of 230 000 pictures, corresponding to 7400 charged current events. This leads to an upper limit for the observed cross section of $\text{σ}{}_{\mathrm{<mtext>obs</mtext>}}\text{< 1.6 × 10}{}^{\mathrm{?42}}\text{(}\text{E}{}_{\mathrm{\nu }}{}^{\mathrm{?}}\text{GeV}\text{)}$ cm² (90% C.L.). Interpretation of this value in terms of the standard W Weinberg-Salam model yields an upper limit to the mixing parameter sin²θ_W < 0.39 at 90% C.L.     

Study of the Kππ system produced in K−p → KππN reactions at 14.3 GeV/c

We have studied the $\text{K}\text{ππ}$ system in the 14.3 GeV/c reactions K^?p → K^?π⁺π^?p, $\text{K}{}^{\mathrm{?}}\text{p}\text{→}\text{K}{}^0\text{π}{}^{\mathrm{?}}\text{π}{}^0\text{and}\text{K}{}^{\mathrm{?}}\text{p}\text{→}\text{K}{}^0\text{π}{}^{\mathrm{+}}\text{π}{}^{\mathrm{?}}\text{n}$. The data have been obtained from a 500 000 picture exposure of the CERN 2m HBC. The first two final states are dominated by Q-production in the Kππ system; there is also an L-signal at M (Kππ) ～ 1.75 GeV. The reaction cross sections are compared to K^?p data at other energies. We discuss the Kππ mass dependence of the diffractive production slope. Evidence is presented for a Q^?p versus Q⁺p differential cross section cross-over around |t| = 0.17 GeV². A t-channel isospin analysis for the $\text{KN}\text{→}\text{K}\text{1(890)π}\text{N}$ channels in the Q-region shows that the I = 1 exchange amplitude is $\text{? 10\%}$ of the dominant I = 0 exchange amplitude. The Kππ decay distributions indicate a predominant J^P = 1⁺ state in the Q-region, and an important J^P = 2^? contribution in the L-region. We find neither s-channel nor t-channel helicity conservation at the meson vertex in the Q- or L-regions. The Kπ angular correlation moments within the Kππ diffractive system are characteristic of Kπ elastic scattering, suggesting a π-exchange Deck-type production mechanism. There is evidence for a Kf⁰ and κπ contribution (where κ is the J^P(Kπ) = 0⁺ state) to the diffractive Kππ system. A fit to the $\text{K}{}^{\mathrm{?}}\text{π}{}^{\mathrm{+}}\text{π}{}^{\mathrm{?}}\text{and}\text{K}{}^0\text{π}{}^{\mathrm{?}}\text{π}{}^0$ Dalitz-plot distributions for the Q-re gion indicates that the ratio of $\text{K}\text{?}\text{to K}{}^1\text{π}$ decay amplitudes decreases with increasing Kππ mass.