RESONANCE PRODUCTION IN PERIPHERAL HEAVY-ION COLLISIONS

Heavy-ion collisions at ultrarelativistic energies may be used as a powerful source of photons and pomerons. We compute the rates for pseudoscalar meson production through two-photon and two-pomeron scattering, at energies that will be available at RHIC and LHC. Light mesons will mostly be produced by pomeron fusion at large rates, the two processes are comparable for charmed mesons, while electromagnetic production will be dominant for bottom mesons. We discuss the possibility of observing the reaction gammagamma(PP) --> R --> gammagamma, and comment on the particular case where R could be a scalar resonance at 650 MeV.

Referral letters in oral medicine: standard versus non-standard letters

Usually referral letters are the only means of communication between general practitioners and specialists in the health area. However, they are inadequate if important basic data are omitted. The aim of this study was to compare the content of standard and non-standard letters. A total of 1956 files from the Oral Medicine Service were consecutively evaluated (March 1996 to September 2000). Key items were considered for analysis and the results were stored in a database using the Epinfo 6.04 program. The X-2 test (a=0.05) was applied to the results. of the 1956 files examined, 34% (662) had a referral letter, 31% of them being standard letters and 69% non-standard letters. Most standard letters (87%) were from professionals of public health institutions. Most percent discrepancies between standard and non-standard letters were observed for patient address (14.90 vs 1.32%), patient age (54.81 vs 9.47%), chief complaint (32.21 vs 8.37%), fundamental lesion (29.33 vs 13.66%), and symptoms (27.81 vs 15.42%,,). Statistically significant differences were observed for patient age, professional referring the patient, chief complaint, and site of the lesion. The quality and quantity of the information differed significantly between the two types of letters. The standard letters were more complete and contained information commonly absent in the non-standard letters. We suggest the use of standard letters for improving the quality of communication among professionals.

On some classes of exactly-solvable Klein-Gordon equations

In this work we discuss some exactly solvable Klein-Gordon equations. We basically discuss the existence of classes of potentials with different nonrelativistic limits, but which shares the intermediate effective Schroedinger differential equation. We comment about the possible use of relativistic exact solutions as approximations for nonrelativistic inexact potentials. (c) 2005 Elsevier B.V. All rights reserved.

Comment on Casimir force in compact non-commutative extra dimensions and radius stabilization

We call attention to a series of mistakes in a paper by S. Nam recently published in this journal (J. High Energy Phys. 10 (2000) 044).

Comment on Wave functions for a Duffin-Kemmer-Petiau particle in a time-dependent potential [J. Math. Phys. 48, 073515 (2007)]

It is shown that the paper Wave functions for a Duffin-Kemmer-Petiau particle in a time-dependent potential by Merad and Bensaid [J. Math. Phys. 48, 073515 (2007)] is not correct in using inadvertently a non-Hermitian Hamiltonian in a formalism that does require Hermitian Hamiltonians.

Reply to Comment on 'Pb1-xCaxTiO3 solid solution (x=0.0, 0.25, 0.50, and 0.75): A theoretical and experimental approach'

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Further on the current algebra of WZNW models at and away from criticality

We comment on the off-critical perturbations of WZNW models by a mass term as well as by another descendent operator, when we can compare the results with further algebra obtained from the Dirac quantization of the model, in such a way that a more general class of models be included. We discover, in both cases, hidden Kac-Moody algebras obeyed by some currents in the off-critical case, which in several cases are enough to completely fix the correlation functions.

Comment on Majoron emitting neutrinoless double beta decay in the electroweak chiral gauge extensions

We point out that if the Majoron-like scheme is implemented within a 3-3-1 model, there must exist at least three different mass scales for the scalar vacuum expectation values in the model. ©1999 The American Physical Society.

Bell's locality condition confronting perfect anti-correlations

We show that Local Realistic Theories, defined as obeying the Bells's locality condition, cannot satisfy the prefect anti-correlations without at the same time maximally violating rotational symmetry at the hidden variable level. We examine whether the rotational symmetry can be restored after the statistical average. We also comment on the question whether such theories are necessarily deterministic at the hidden variable leva. © 1999 Elsevier Science B.V. All rights reserved.

Comment on Time-reversal symmetry-breaking superconductivity

It is pointed out that erroneous Bardeen-Cooper-Schrieffer model equations have been used by Haranath Ghosh in his recent treatment of time-reversal symmetry-breaking superconductivity. Consequently, his numerical results are misleading, and his conclusions are not to the point.

Comment on 'Relativistic extension of shape-invariant potentials'

This comment criticizes the recently published approach of Alhaidari for solving relativistic problems. It is shown that his gauge considerations are inaccurate and that the class of exactly solvable relativistic problems is not as large as the author claims.