Annihilation diagram contribution to charmonium masses

In this work, we generate gauge configurations with \begin{document}$ N_f = 2 $\end{document} dynamical charm quarks on anisotropic lattices. The mass shift of \begin{document}$ 1S $\end{document} and \begin{document}$ 1P $\end{document} charmonia due to the charm quark annihilation effect can be investigated directly in a manner of unitary theory. The distillation method is adopted to treat the charm quark annihilation diagrams at a very precise level. For \begin{document}$ 1S $\end{document} charmonia, the charm quark annihilation effect barely changes the \begin{document}$ J/\psi $\end{document} mass, but lifts the \begin{document}$ \eta_c $\end{document} mass by approximately 3–4 MeV. For \begin{document}$ 1P $\end{document} charmonia, this effect results in positive mass shifts of approximately 1 MeV for \begin{document}$ \chi_{c1} $\end{document} and \begin{document}$ h_c $\end{document}, but decreases the \begin{document}$ \chi_{c2} $\end{document} mass by approximately 3 MeV. We did not obtain a reliable result for the mass shift of \begin{document}$ \chi_{c0} $\end{document}. In addition, we observed that the spin averaged mass of the spin-triplet \begin{document}$ 1P $\end{document} charmonia is in good agreement with \begin{document}$ h_c $\end{document}, as expected by the non-relativistic quark model and measured by experiments.     

Semileptonic bc to cc and bb to bc baryon decays and heavy quark spin symmetry

We study the semileptonic decays of the lowest-lying bc baryons to the lowest-lying cc baryons （Ξ （＊） bc → Ξ （＊） cc and Ω （ ＊） bc → Ω （＊） cc ）,in the limit m b,m c Λ QCD and close to the zero recoil point.The separate heavy quark spin symmetries make it possible to describe all these decays using a single form factor.We also show how these constraints can be used to test the validity of different quark model calculations.bb to bc baryon decays are also discussed.     

Effect of parton cascade to medium

Jet quenching has been proposed as a probe of the properties of the strongly interacting quarkgluon-plasma in high energy heavy ion collisions.At the meantime,it is also important to study the excitation of medium by propagating jets.Based on Boltzmann equation,a Monte Carlo was constructed to simulate the elastic collisions with thermal partons by energetic jets.Medium modification due to jet-medium interaction has been studied within this model in a uniform medium.     

Response of thermoluminescent detectors to charged particles and to neutrons

Thermoluminescent detectors (TLDs) are widely used for the dosimetry of photons and electrons. They are less used for the radiation with higher linear energy transfer (LET). One of the reasons for that is that their TL relative efficiency η decreases for the most of them with increasing LET.

The paper presents first a review of author's experimental results in which η was established for charged particles having LET of the order from 1 to 100 keV/μm in tissue. Among TLDs studied were known materials like LiF:Mn; Ti; Al–P glass; CaSO₄:Dy; Al₂O₃:Na; and Al₂O₃:C. It was found that the dependence of their η on LET is not the same for all TLDs studied.

The response of the same materials to neutrons was also studied. It was found that both η as the relative response (RR) defined in terms of absorbed dose in tissue are different, they depend critically also on the composition. When a TLD contains nuclei like ⁶Li and ¹⁰B, their RR would be rather high. As far as η is concerned, the same tendencies were observed as for charged particles, i.e. when average LET of secondary particles formed in a TLD increases, their η generally decreases.     

Dynamic Logic Assigned to Automata

A dynamic logic B can be assigned to every automaton Open image in new window without regard if Open image in new window is deterministic or nondeterministic. This logic enables us to formulate observations on Open image in new window in the form of composed propositions and, due to a transition functor T, it captures the dynamic behaviour of Open image in new window . There are formulated conditions under which the automaton Open image in new window can be recovered by means of B and T.     

Pauli blocking potential applied to heavy-ion fusion reactions

In this study, the Pauli blocking potential between two colliding nuclei in the density overlapping region is applied to describe the heavy nuclei fusion process. Inspired by the Pauli blocking effect in the \begin{document}$ \alpha $\end{document}-decay of heavy nuclei, the Pauli blocking potential of single nucleon from the surrounding matter is obtained. In fusion reactions with strong density overlap, the Pauli blocking potential between the projectile and target can be constructed using a single folding model. By considering this potential, the double folding model with a new parameter set is employed to analyze the fusion processes of 95 systems. A wider Coulomb barrier and shallower potential pocket are formed in the inner part of the potential between the two colliding nuclei, compared to that calculated using the Akyüz-Winther potential. The fusion hindrance phenomena at deep sub-barrier energies are described well for fusion systems \begin{document}$ ^{16} $\end{document}O + \begin{document}$ ^{208} $\end{document}Pb and \begin{document}$ ^{58} $\end{document}Ni + \begin{document}$ ^{58} $\end{document}Ni.     

Solution to the Rarita-Schwinger equations

A systematical method is presented for solving the relativistic wave equations for particles of arbitrary spin. Explicit helicity relativistic wave functions for particles with arbitrary spin are derived rigorously. Received: 22 August 2001 / Revised version: 5 July 2002 / Published online: 9 December 2002 RID="a" ID="a" Corresponding author.     

A thermostatistical approach to protein structures

In this study, the relation between the additional heat capacities of proteins have been obtained. The expressions for the increments of enthalpy , entropy and Gibbs energy which are encountered in the dissolving of the proteins in water, have been calculated. Partition functions of proteins are related to the macrothermodynamical quantities with the help of free energies. In order to endeavour the structure of the proteins, the theoretical calculations of thermostatistical mechanics are fitted to the data of experimental results.     

Modifications to the lidar equation due to nonlinear propagation in air

We study how the well-known lidar equation is affected by the use of ultra-short, high-power laser pulses. Because of the self-focusing and self-guiding, the overlap function ξ, representing the reduction fraction of the signal resulting from geometrical effects inside the experimental system, needs to be reconsidered. The losses due to multi-photon ionisation in the filament entail a heavy weakening of the return signal. We also investigate the contribution of the white-light components generated by self-phase modulation. Received: 2 January 2001 / Revised version: 8 June 2001 / Published online: 18 July 2001     

K-nucleus dynamics: from quasibound states to kaon condensation

Coupled-channel KN dynamics near threshold and its repercussions in few-body K-nuclear systems are briefly reviewed,highlighting studies of a K - pp quasibound state.In heavier nuclei,the extension of mean-field calculations to multi-K nuclear and hypernuclear quasibound states is discussed.It is concluded that strangeness in finite self-bound systems is realized through hyperons,with no room for kaon condensation.     

Semiclassical approach to time-dependent tunnelling

We present an exact time-dependent semiclassical formulation of the dynamics of a -atom subjected to an oscillating electric field. Through a simple approximation the results of Ergenzinger's more intuitive analysis are obtained. We also comment on the important role played by the imaginary tunnelling time , which is quite distinct from the usual adiabatic tunnelling time. Received: 24 April 2001 / Revised version: 15 May 2001 / Published online: 3 August 2001     

How to get access to long range states of highly excited molecules

Due to competition between ionic and covalent dissociation, the excited potential curves of the alkali dimers display long range structures, leading in some cases to secondary wells. We discuss the possibility of populating the well (with a depth of 1614.8 cm^-1, located at R _e = 30.5a ₀ ) that is present in the Na₂ potential curve and propose detection schemes. Received: 28 May 1998 / Revised: 5 August 1998 / Accepted: 24 September 1998