Nuclear stopping power in αα anddd collisions

Inelasticαα anddd collisions were studied at a centre-of-mass energy √S _NN=31.2 GeV per nucleon-nucleon collision, using the Split-Field Magnet (SFM) detector at the CERN ISR. In this paper we show the inclusive and semi-inclusive rapidity distributions of protons, compare them with predictions of the Lund model, and calculate the average rapidity loss for participant protons. From the negative particles we calculate the inelasticity of the interaction, the average energy per particle, and the degree of isotropy of the produced hadrons.     

On the decay of61Zn and60Zn using mass separated sources

The γ-ray spectrum of⁶¹Zn and⁶⁰Zn was studied with a 75 cm³ Ge(Li) detector using mass separated sources. For the half-lives we foundT _1/2(⁶¹Zn)=89.1 ± 0.2 sec andT _1/2(⁶⁰Zn)=2.33 ±0.05 min, together with the valuesT _1/2(⁶¹Cu)=3.26± 0.05 hr andT _1/2(⁶⁰Cu)=24.0 ± 0.3 min for the half-lives of the daughter activities.     

Water Vapor Sorption in Cementitious Materials—Measurement,Modeling and Interpretation

The rate and extent of uptake and release of moisture are critical in controlling the behavior of cementitious materials ranging from fluid transport to hygral deformations. While classically determined using an equilibrium (static) salt solution method (Baroghel-Bouny in Cem Concr Res 37:414–437, 2007), advanced capabilities offered by gravimetric dynamic vapor sorption (DVS) analyzers, are now permitting acquisition of sorption spectra at microgram ( $\upmu \hbox {g}$ ) resolution on the order of a few weeks. This work highlights new multicycle determinations of adsorption/desorption isotherms, acquired using a custom-built DVS analyzer for well-hydrated alite and ordinary portland cement pastes over a range of water-to-solid ratios ( $w/s$ , mass basis). Special focus is paid to describe measurement aspects relevant to acquiring reliable spectra, and their interpretation. Sorption isotherms are used to assess transport properties, and sorption hysteresis and its irreversibility following first drying. Based on an optimization-based criterion, the Young-Nelson model is selected to simulate sorption evolutions, including the effects of hysteresis. Sensitivity analyses carried out using this model are used to understand the role of parameters, including porosity and $w/s$ , on the hysteresis that develops from the first to subsequent sorption cycles.     

Direct measurement of the Chudakov effect

Experimental results for the restricted energy loss of pairs created from 1-178 GeV photons in a thin Au target and subsequently passing a CCD detector are presented. It is shown that pairs--when detected close to the creation vertex--suffer a reduced energy loss due to the internal screening of the charges constituting the pair. Furthermore, the ability to measure directly the energy of the pair by calorimetry enables a comparison with theory as a function of energy. The observed phenomenon is in good qualitative agreement with general expectations from the Chudakov effect but indicates a quantitative disagreement with either of two mutually disagreeing theories.     

Search for narrow baryonium states near the NN threshold

The reactions $\text{p}\text{p}\text{→π}{}^{\mathrm{?}}\text{X}\text{and}\text{p}\text{d}\text{→}\text{pX}$ earch for narrow baryonium states in the mass region between 1.6 and 2.0 GeV/c². No such state has been observed. In the first reaction the upper limit for the production of narrow baryonium states is 8μb/sr for a 3 standard deviation signal with 4 MeV/c² width. In the second reaction this limit is 10 μb/sr. The second reaction is rather insensitive for observation of baryonium states as it is dominated by quasi-free contributions.     

Hypernuclei with sigma particles

The production of Σ particles in the (K⁻, π⁻) on ⁹Be at 720 MeV/c has been studied at the CERN proton synchrotron (PS). The missing-mass spectrum shows structures in the Σ region, which have been interpreted as belonging to hypernuclei with sigma particles. An upper limit of 8 MeV for the width of these states has been estimated.     

Structural arrest in an ideal gas

We report a molecular dynamics study of a simple model system that has the static properties of an ideal gas, yet exhibits nontrivial "glassy" dynamics behavior at high densities. The constituent molecules of this system are constructs of three infinitely thin hard rods of length L, rigidly joined at their midpoints. The crosses have random but fixed orientation. The static properties of this system are those of an ideal gas, and its collision frequency can be computed analytically. For number densities NL(3)/V>1, the single-particle diffusivity goes to zero. As the system is completely structureless, standard mode-coupling theory cannot describe the observed structural arrest. Nevertheless, the system exhibits many dynamical features that appear to be mode-coupling-like. All high-density incoherent intermediate scattering functions collapse onto master curves that depend only on the wave vector.