A diquark model for baryons containing one heavy quark

We present a phenomenological ansatz for coupling a heavy quark with two light quarks to form a heavy baryon. The heavy quark is treated in the heavy mass limit, and the light quark dynamics is approximated by propagating scalar and axial vector ‘diquarks’. The resulting effective lagrangian, which incorporates heavy quark and chiral symmetry, describes interactions of heavy baryons with Goldstone bosons in the low energy region. As an application, the Isgur-Wise form factors are estimated.     

K-X-ray spectrum of the Pb + Pb quasimolecules

We present ab initio calculations of the quasimolecular K-X-ray spectrum from the Pb + Pb system, where both the Kd-hole amplitude and the radiation amplitude is calculated in first order perturbation theory. A comparison with the background radiation like NNB, SEB and γ-decay of excited nuclei shows that the molecular X-rays should be measurable up to X-ray energies corresponding to the characteristic K-line of the united superheavy atom.     

Notiz über die Herstellung von Na2S2O7 aus NaHSO4·H2O

While the thermal decomposition of NaHSO₄ · H₂O at 1 atm yields Na₂S₂O₇ of ca. 90% purity only, it is possible to obtain products of 98% purity in vacuum at 170? C.     

Normal strobovideolaryngoscopy: Variability in healthy singers

Strobovideolaryngoscopy has proven essential to accurate diagnosis of voice disorders. Clinical interpretation of stroboscopic images usually follows a standard assessment protocol. Features analyzed typically include symmetry of amplitude, symmetry of phase, regularity of periodicity, amplitudes and wave forms of individual vocal folds, presence or absence of a dynamic segments, and other features. Speed and smoothness of abduction and adduction are also assessed. In order for stroboscopic data to be used meaningfully in a clinical setting, it is essential for the laryngologist to recognize the range of normal variability of these parameters. This may be particularly important when trying to establish diagnoses for subtle voice disorders in professional voice users. This study investigates strobovideolaryngoscopic findings in a population of normal professional singers without voice complaints. “Abnormal” strobovideolaryngoscopic findings occur in this asymptomatic population of “volunteers”. These abnormalities might have been misinterpreted as causing voice complaints if seen for the first time when the singer sought medical care for a voice problem. Physicians must be aware of the range of laryngeal behavior that may be found among normal subjects and must be cautious when interpreting strobovideolaryngoscopic findings. This study also highlights the importance of obtaining “normal” baseline strobovideolaryngoscopic evaluations on professional voice users. The review of strobovideolaryngoscopy performed upon 65 healthy, asymptomatic professional singers revealed an incidence of 58% “abnormal” findings as six clinical entities.     

Angular correlations of electron-positron pairs produced in heavy-ion collisions

We investigate the strength of angular correlations between coincident electron-positron pairs produced in Pb + Pb collisions at 5.7 MeV/u. The angular correlations are predicted to be observable at electron energies above 200 keV, almost independent of positron energy.     

Models for new particle production in nuclear collisions

Following up our earlier work and also stimulated by recent experimental results on positron production in heavy ion collisions we investigate various mechanisms for the production of a light, previously unknown particle in such collisions. As more conventional mechanisms seem to be inadequate we concentrate on processes directly or indirectly connected with the strong electric or magnetic fields and quark degrees of freedom in nuclei. We also consider modifications of the color confinement scheme. Our analysis is confined to schemes staying within the framework of the standardSU(3)_c ×SU(2)×U(1) model. Since most of the possibilities discussed can be rejected, severe modifications of basic concepts of particle physics seem to be required if the production of a new particle is confirmed.