Half-lives of the new isotopes100Rb,100Sr,148Cs and of99Rb,99Sr and147Cs

An improvement of the ion source of the online fission product separator OSTIS allowed us to identify the new isotopes¹⁰⁰Rb(50±10 msec),¹⁰⁰Sr (170±80 msec) and¹⁴⁸Cs(130±40 msec). Half-lives for⁹⁹Rb(59±4 msec),⁹⁹Sr(290±40 msec) and¹⁴⁷Cs(235±10 msec) were redetermined. All values were obtained by following the activity build-up and decay with β-multiscaling and γ-multispectra measurements.     

Particle production in hadron-nucleus collisions at 100 GeV from a parton-string model

We calculate the inclusive momentum distribution of particles produced in a hadron-nucleus (hA) collision. The exchange of colour between the projectile and target nucleons leads to the formation of colour strings which are assumed to fragment like strings formed in deep inelastic lepton-nucleon scattering. Making a few basic hypotheses we consistently and parameterfree describe the projectile fragmentation region in collisions of the typehA→h′X withh=p, π⁺ andh′=p, π⁺, π^? at 100 GeV incident energy.     

Translationally invariant calculations of form factors, nucleon densities and momentum distributions for finite nuclei with short-range correlations included

Relying upon our previous treatment of the density matrices for nuclei (in general, nonrelativistic self-bound finite systems) we are studying a combined effect of center-of-mass motion and short-range nucleon-nucleon correlations on the nucleon density and momentum distributions in light nuclei (⁴He and ¹⁶O). Their intrinsic ground-state wave functions are constructed in the so-called fixed center-of-mass approximation, starting with mean-field Slater determinants modified by some correlator (e.g., after Jastrow or Villars). We develop the formalism based upon the Cartesian or boson representation, in which the coordinate and momentum operators are linear combinations of the creation and annihilation operators for oscillatory quanta in the three different space directions, and get the own “Tassie-Barker” factors for each distribution and point out other model-independent results. After this separation of the center-of-mass motion effects we propose additional analytic means in order to simplify the subsequent calculations (e.g., within the Jastrow approach or the unitary correlation operator method). The charge form factors, densities and momentum distributions of ⁴He and ¹⁶O evaluated by using the well-known cluster expansions are compared with data, our exact (numerical) results and microscopic calculations.     

Target mass dependence of the average linear momentum transfer

The average transferred linear momentum in nuclear reactions induced by ³He, ⁴He, ¹⁴N, and ²⁰Ne projectiles on Co, Cu and Ag targets was determined by thick-target-thick-catcher recoil range techniques for bombarding energies between 10 AMeV and 90 AMeV. A comparison with results obtained from fission fragment angular correlations indicates a strong target mass dependence of the linear momentum transfer.     

Beta decay energies and nuclear masses of148Ba,148La and151Pr

Theβ-decay energy of the neutron-rich isotopes¹⁴⁸Ba,¹⁴⁸La and¹⁵¹Pr has been measured at the Institute Laue-Langevin (ILL). The¹⁴⁸Ba- and¹⁴⁸La-nuclei were produced using a high-temperature ion source at the OSTIS separator of this institute, whereas samples of¹⁵¹Pr were obtained from the thermal fission of²³⁹Pu, used as a target in the mass separator LOHENGRIN. At both instruments,βγ-coincidences were measured with a plastic scintillator telescope and a Ge(I)-detector, together withβ-singles andγ-singles spectra. Theβ-spectra emitted in coincidence with 44γ-lines in the decay of these nuclei have been evaluated. From their endpoint energies, the followingQ _β -values have been obtained:Q _β (¹⁴⁸Ba)=5115±60keV;Q _β (¹⁴⁸La)=7255±55 keV;Q _β (¹⁵¹Pr)=4170±75 keV. Using these results, the nuclear massesA of these nuclei can be calculated with a relative error ΔA/A?5·10^?7. In addition, the two-neutron separation energies and the mass excesses have been derived; the results are compared with recent predictions of theoretical mass calculations.     

12C(e,e′ p) missing momentum distributions in HF-Sk3 and RPA-Sk3 continuum theories

We study the momentum distribution or reduced cross-section for electron induced 1p _3/2 proton knockout from¹²C in parallel kinematics. We refer to continuum self-consistent HF-Sk 3 and RPA-Sk 3 theories with a full treatment of the one-nucleon energy continuum. The PWIA limit is also shown. The¹²C(e, e′p ₀) missing momentum distribution is analyzed in connection with the energy dependence at fixed momentum transfer of the¹²C(e, e′) longitudinal and transverse responses. We compare our theoretical results with the available experimental data.     

Atomic masses of147m, 148m, 149m Tb,148Dy,150m, 152m Ho derived from decay properties

Using nuclear fusion reactions of⁴⁰Ar ions with¹¹²Cd,¹¹⁴Sn and¹¹⁶Sn and subsequentγ-ray spectroscopy, the probability ratios of positron emission and electron capture,β ⁺/EC _k andβ ⁺/(EC+β ⁺), are determined for individualβ-transitions in the decay of^147m ,^148m ,^149m Tb,¹⁴⁸Dy and^150m ,^152m Ho. From comparison with theoretical ratios the followingQ _EC values, given in keV, are derived:^147m Tb, 4.620(60);^148m Tb, 5.730(30);^149m Tb, 3.610(50);¹⁴⁸Dy, 2.680(30);^150m Ho, 6.625(120) and^152m Ho, 6.470(80). The present decay-energy data are compared with earlier measurements and the new information obtained for the mass surface around¹⁴⁶Gd is discussed.     

Measurement of the stopping power for μ− and μ+ at energies between 3 keV and 100 keV

Spin polarization of⁴³Ti produced through the projectile fragmentation process in⁴⁶Ti on C collisions at 116 MeV/nucleon has been observed as a function of fragment momentum by means of beta-decay asymmetry. From the momentum dependence of the fragment polarization, it was concluded that negative angle deflection of the⁴³Ti fragment due to the nuclear attractive potential is the main reaction path in the case of light targets.     

Yrast isomers and very high spin states in 148, 149, 151, 152Dy and 147Gd

We have studied level schemes for the feeding and decay of high-spin isomers in the nuclei ^{148, 149, 151, 152}Dy and ¹⁴⁷ Gd. A variety of techniques involving γ-ray spectroscopy with pulsed heavy-ion beams have been applied including linear polarization, γ-γ correlations and recoil distance measurements.The general aspect of these level schemes is in accordance with the idea that the states near and along the yrast line can be described by a spheroidal shell model in which the nucleus is axially symmetric with respect to the total spin. In these cases the spin is generated not by collective rotation, but by alignment of many single-particle orbits around a common axis.     

Cluster models,local compensation of transverse momenta and transverse data

We analyse various data available on transverse momentum properties of high-energy collisions, within the framework of cluster models. The mean transverse momentum square of clusters is estimated to be of the order of 0.3 (GeV/c)². The transverse data at FNAL are found to be unable to discriminate between various production amplitudes. We give predictions at ISR on the transverse momentum transfer fluctuation $\text{D}{}_{\mathrm{?}}{}^2\text{(Δy)}$, which would permit this discrimination.     

Transverse momentum distribution of partons in QCD

The renormalization group approach is applied to the study of transverse momentum distribution of partons in QCD. We generalize the method of Altarelli and Parisi to obtain a formula for the mean squared average transverse momentum as a function of Q² and x, the virtual photon mass squared and the longitudinal momentum fraction of the parton. For large Q², it decreases with x in addition to the expected increase with Q². This x-dependence reduces substantially the transverse momentum of massive μ-pairs produced by hadronic collisions from its linear dependence on $\text{(}\text{Q}{}^2\text{ln}\text{Q}{}^2\text{)}\text{1}\text{2}$.     

Impact parameter selected nuclear temperatures of hot nuclei from excited state populations for 40Ar+197 Au reactions at E/A=25MeV

Nuclear temperatures extracted from excited state populations were measured as a function of linear momentum transfer (LMT) for ⁴⁰Ar+¹⁹⁷ Au reactions at 25MeV/nucleon. The emission temperatures increased slightly with increasing linear momentum transfer or decreasing impact parameter. Taking into account the corrections of detection efficiency and sequential feeding from higher-lying states, a temperature of T ≈ 4MeV was deduced for central collisions. For peripheral collisions the extracted temperatures increased with the energy of the particles.     

Higher twist contributions from the direct pion coupling ine + e − annihilation,photoproduction and π− p Drell-Yan

We present calculations of normalized higher twist contributions in three processes in which the central sub-processes are related by crossing: the production of hadrons at high transverse momentum relative to the thrust axis ine ⁺ e ^? annihilation, photoproduction of high transverse momentum pions from a proton target, and high transverse momentum lepton pair production in π^? p collisions. The last of these is most interesting, not only because the higher twist contribution is significant, but also the QCD interpretation of the data is uncertain.     

Li(p,pd)He reaction at 100 MeV

An angular correlation experiment of the ⁶Li(p, pd)⁴He reaction at 100 MeV has been performed using a symmetric and coplanar geometry and covering an angular range from 45.5 to 57°. In addition to the conventional ΔE-E telescope systems for the detection of both protons and deuterons, a 14° analyzing magnet was employed to select deuterons of a given momentum range. The results for the ground state transition are consistent with those obtained at other incident energies. The angular distribution for the transition to the 20 MeV excited state of the recoiling α-particle was also obtained and the overall magnitude of the differential cross section is at least an order of magnitude smaller than that of the ground state transition. The plane wave impulse approximation (PWIA) was used to analyze the experimental results. A form factor was generated using the Saxon-Woods potential as the d-α inter-cluster potential. Satisfactory agreement between theory and experiment was obtained. A value of 0.45 ±0.08 was extracted for the deuteron clustering probability on ⁶Li. The exchange and the optical distortion effects were also discussed.     

Unified treatment of one-range addition theorems for integer and non-integer n-STO, -GTO and -generalized exponential type orbitals with hyperbolic cosine in position, momentum and four-dimensional spaces

Simpler formulas are derived for one-range addition theorems for the integer and noninteger n generalized exponential type orbitals, momentum space orbitals, and hyperspherical harmonics with hyperbolic cosine (GETO HC, GMSO HC, and GHSH HC) in position, momentum and four-dimensional spaces, respectively. The final results are expressed in terms of one-range addition theorems of complete orthonormal sets of ψα -exponential type orbitals, α - momentum space orbitals and z α -hyperspherical harmonics. We notice that the one-range addition theorems for integer and noninteger n-Slater type orbitals and Gaussian type orbitals in position, momentum and four dimensional spaces are special cases of GETO HC, GMSO HC, and GHSH HC. The theorems presented can be useful in the accurate study of the electronic structure of atomic and molecular systems.     

Anregung des 7,66 MeV-Niveaus in Kohlenstoff-12 durch unelastische Elektronenstreuung

Using the facilities of the Darmstadt electron linear accelerator the cross section for the excitation of the 7.66 MeV level in Carbon-12 was measured for momentum transfers between 0.25 and 0.55 fm^?1. Extrapolation of the measured cross sections for vanishing momentum transfer yields a partial width for the decay to the ground state through internal pair production of (7.3±1.3)·10^?5 eV. The dependence of the reduced transition probability on momentum transfer is discussed and compared with theoretical predictions.     

Elastic properties of amorphous solids below 100 K

We have performed a survey of the available literature on the speed of sound at temperatures above 5 K in amorphous solids. We have compared the slope, β, of the linear variation in the speed of sound at these temperatures with the temperature independent internal friction below 10 K, Q _o ^{? 1} , and find that, empirically, β = 0.5 Q _o ^?1 /K. This suggests that the low temperature properties of amorphous solids are connected with their universal behavior at higher temperatures. Additionally, we have extended our survey to crystals with glass-like properties as well as to quasicrystals. We find that the same relationship that exists in amorphous solids between Q _o ^?1 and β exists in these solids as well. A model to explain this very general empirical relation does not seem to exist.     

Excited levels of 148Ce

Available experimental data on excited levels of the ¹⁴⁸Ce nucleus are analyzed. With the aid of model concepts and systematics that cover neighboring nuclei, the spectrum of ¹⁴⁸Ce is supplemented with a K ^π = 2^? rotational band that has a bandhead at 1368.98 keV, which extends up to the 16^? state at 3897.9 keV, and which is new. Three states at E = 1422.85, 1786.57, and 2198.6 keV of spin-parity 5⁺, 7⁺, and 9⁺, respectively, are included in the gamma-vibrational band featuring the known 2⁺ and 3⁺ levels at 989.90 and 1116.63 keV, respectively. A significant difference in the behavior of the moments of inertia in positive-and negative-parity bands is highlighted.     

Three-alpha force and the 3-α model of12C

We postulate a Gaussian three-body potential amongα particles and adjust its parameters so that, when it is added to the Ali-Bodmerα-α potential, a good fit to experimental energies of low-lying 0⁺ and 2⁺ states of¹²C is achieved. With these potentials we made a linear variational calculation in a basis of harmonic oscillator functions which are translationally invariant, completely symmetric, and have a definite orbital angular momentum. We study the influence of this three-body potential on elastic and inelastic form factors, transition widths, Coulomb energy and charge radius of the 3-α system. The 3-α potential improved results found with the Ali-Bodmer potential alone. We find the 0 ₂ ⁺ state to be a (non-rigid) linear chain and the ground state to be a triangle ofα particles.     

Energy, momentum, and force in classical electrodynamics: Application to negative-index media

The classical theory of electromagnetism is based on Maxwell's macroscopic equations, an energy postulate, a momentum postulate, and a generalized form of the Lorentz law of force. These seven postulates constitute the foundation of a complete and consistent theory, thus eliminating the need for physical models of polarization P and magnetization M — these being the distinguishing features of Maxwell's macroscopic equations. In the proposed formulation, P(r, t) and M(r, t) are arbitrary functions of space and time, their physical properties being embedded in the seven postulates of the theory. The postulates are self-consistent, comply with special relativity, and satisfy the laws of conservation of energy, linear momentum, and angular momentum. The Abraham momentum density p_EM(r,t) = E(r,t) × H(r,t) / c² emerges as the universal electromagnetic momentum that does not depend on whether the field is propagating or evanescent, and whether or not the host media are homogeneous, transparent, isotropic, linear, dispersive, magnetic, hysteretic, negative-index, etc. Any variation with time of the total electromagnetic momentum of a closed system results in a force exerted on the material media within the system in accordance with the generalized Lorentz law.