Wavelength-shifting fibers for calorimetric measurements in a long base line neutrino oscillation experiment

Abstract The NOE Collaboration has proposed a calorimeter to measure the energy of the final states of ν interaction events. The properties of long scintillator bars with wavelength-shifting fiber readout have been studied to develop a calorimeter design option. Various prototypes have been exposed to a cosmic rays stand. The total measured light yield in the middle of a 6 m -long fiber is about 15 photoelectrons. With this photon collection performance, it has been simulated that the calorimeter can achieve 17%/ E and 50%/ E resolutions for electrons and pions, respectively

Azimuthal asymmetries of charged hadrons produced by high-energy muons scattered off longitudinally polarised deuterons

Azimuthal asymmetries in semi-inclusive production of positive (h^+) and negative hadrons (h^-) have been measured by scattering 160 GeV muons off longitudinally polarised deuterons at CERN. The asymmetries were decomposed in several terms according to their expected modulation in the azimuthal angle phi of the outgoing hadron. Each term receives contributions from one or several spin and transverse-momentum-dependent parton distribution and fragmentation functions. The amplitudes of all phi-modulation terms of the hadron asymmetries integrated over the kinematic variables are found to be consistent with zero within statistical errors, while the constant terms are nonzero and equal for h^+ and h^- within the statistical errors. The dependencies of the phi-modulated terms versus the Bjorken momentum fraction x, the hadron fractional momentum z, and the hadron transverse momentum p_h^T were studied. The x dependence of the constant terms for both positive and negative hadrons is in agreement with the longitudinal double-spin hadron asymmetries, measured in semi-inclusive deep-inelastic scattering. The x dependence of the sin phi-modulation term is less pronounced than that in the corresponding HERMES data. All other dependencies of the phi-modulation amplitudes are consistent with zero within the statistical errors.Comment: 12 pages, 11 Figures; revision 1 signs in Eq 5 corrected, polishe

Black Hole Thermodynamics and Statistical Mechanics

We have known for more than thirty years that black holes behave as thermodynamic systems, radiating as black bodies with characteristic temperatures and entropies. This behavior is not only interesting in its own right; it could also, through a statistical mechanical description, cast light on some of the deep problems of quantizing gravity. In these lectures, I review what we currently know about black hole thermodynamics and statistical mechanics, suggest a rather speculative "universal" characterization of the underlying states, and describe some key open questions.Comment: 35 pages, Springer macros; for the Proceedings of the 4th Aegean Summer School on Black Hole

SPECTRAL CHARACTERISTICS OF DENTAL HARD TISSUES AND THEIR CLINICAL RELEVANCE

Raman spectroscopy is a molecular specific technique which can be used to develop a fundamental biochemical understanding of tissue physiology and pathology. This method is non-invasive and nondestructive: it utilizes a monochromatic light source to determine sample chemical composition. Raman spectroscopy has become widely used in different fields of medicine, including dentistry. The aim of the study is to assess the spectral characteristics (Raman fluorescent components) of dental hard tissues and to evaluate the usability of the method for the assessment of mineralization of dental hard tissues. In the in vitro study, Raman-fluorescent spectroscopy of teeth (incisors, premolars, molars) extracted due to clinical indications was performed. The results of the preliminary study confirmed the advantages of using wet samples for the evaluation, as it allowed to increase the sensitivity of Raman spectroscopy. Therefore, all the teeth used were kept for 30 minutes in deionized water prior to the experiment. Laser spectroscopic complex " InSpectr M" (Russia) with 514 nm wavelength was used. A qualitative and quantitative assessment of the content and distribution of hydroxyapatite in sound and demineralized dental hard tissues (enamel, dentin, cement) was performed. According to our results, for all groups the content of hydroxyapatite in enamel, as a more mineralized tissue, was higher, than that in dentin, cement and enamel carious lesions. High sensitivity and rapidity of the method as well as the possibility to quantitatively assess the spectroscopic results were revealed. That allows using Raman spectroscopy in the assessment of mineralization and remineralization of dental hard tissues, effectiveness of remineralizing medications and algorithms of their use in clinical practice