BFKL resummation effects in the <Emphasis Type="Italic">γ</Emphasis><Superscript>*</Superscript><Emphasis Type="Italic">γ</Emphasis><Superscript>*</Superscript> total hadronic cross section

We study in the BFKL approach the total hadronic cross section for the collision of two virtual photons for energies in the range of LEP2 and in the range of future linear colliders. The BFKL resummation is done at the next-to-leading order in the BFKL Green’s function; photon impact factors are taken instead at the leading order, but with the inclusion of the subleading terms required by invariance under changes of the renormalization scale and of the BFKL scale s ₀. We compare our results with previous estimates based on a similar kind of approximation.     

Inverse kinematics resonance scattering on thick target with EXCYT beams

The resonance scattering method in inverse kinematics on infinite target has been applied to two systems, ¹⁸O + α and ⁹Be + α, in order to test and to optimize an experimental apparatus in view of a set of resonance scattering experiments to be performed with ⁸Li and ⁹Li radioactive ion beams delivered by the facility EXCYT. The scattering excitation functions, deduced for the two systems, were compared with previous results reported in literature. Results show that reliable stopping power data are essential for the application of this technique.     

Phase behavior of (CO2 + methanol + lauric acid) system

In this study the phase equilibrium behaviors of the binary system (CO₂ + lauric acid) and the ternary system (CO₂ + methanol + lauric acid) were determined. The static synthetic method, using a variable-volume view cell, was employed to obtain the experimental data in the temperature range of (293 to 343) K and pressures up to 24 MPa. The mole fractions of carbon dioxide were varied according to the systems as follows: (0.7524 to 0.9955) for the binary system (CO₂ + lauric acid); (0.4616 to 0.9895) for the ternary system (CO₂ + methanol + lauric acid) with a methanol to lauric acid molar ratio of (2:1); and (0.3414 to 0.9182) for the system (CO₂ + methanol + lauric acid) with a methanol to lauric acid molar ratio of (6:1). For these systems (vapor + liquid), (liquid + liquid), (vapor + liquid + liquid), and (solid + fluid) transitions were observed. The phase equilibrium data obtained for the systems were modeled using the Peng–Robinson equation of state with the classical van der Waals mixing rule with a satisfactory correlation between experimental and calculated values.     

Photoacoustic study of a two-layer system: Implanted silicon

Summary We have studied the behaviour of photoacoustic response of implanted silicon samples in order to measure the thermal conductivity of damaged layers; the results allow us to determine such a parameter simply by the phase difference measurement between implanted and unimplanted regions of the sample.

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Riassunto è stata studiata la risposta fotoacustica di campioni di silicio impiantato allo scopo di misurare la conducibilità termica degli strati danneggiati; i risultati permettono di determinare questa grandezza misurando semplicemente la differenza di fase tra la zona impiantata e quella cristallina del campione.

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Резюме Исследуется поведение фотоакустического отклика на образцах имплантированного кремиия, чтобы измерить теплопроводность поврежденных слоев. Полученные результаты позволяют получить величину теплопроводности с помощью измерения разности фаз между имплантированной и неимплантированной областлми образца.

     

Photoacoustic measurements of ion-implanted semiconductors

Summary We have measured photoacoustic-signal amplitude and phase of ion-implanted semiconductors. The main factors which determine the photoacoustic behaviour of implanted samples are the opticalabsorption coefficient and the thermal conductivity of the implanted layer. For the thermal conductivity of such a layer a value has been found like that for vitreous materials. Experimental results are in agreement with theoretical models which describe the photoacoustic response of a two-layer sample.

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Riassunto Sono state eseguite misure di segnale fotoacustico e di fase in semiconduttori impiantati. Le grandezze che caratterizzano il comportamento fotoacustico di tali sistemi sono il coefficiente di assorbimento ottico e la conducibilità termica dello strato impiantato. Si è trovato per lo strato impiantato una conducibilità termica simile a quella dei vetri. I risultati sperimentali sono in accordo con i modelli teorici che descrivono la risposta fotoacustica di campioni costituiti da due strati.

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Резюме Измеряются фотоакустические ситналы и фазы в ионно-имплантированных полупроводниках. Основные величины, которые характеризуют фотоакустическое поведение имплантированных образцов, представляют коэффициент оптического поглощения и теплопроводность имплантированного слоя. Для теплопроводности имплантированного слоя получена беличина аналогичная для стеклообразных материалов. Экспериментальные результаты согласуются с теоретнческими моделями, которые описывают фотоакустический отклик для двухслойного образца.

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To speed up publication, the authors of this paper have agreed to not receive the proofs for correction.     

Determination of the angular and energy dependence of hard constituent scattering from π0 pair events at the CERN intersecting storage rings

We present data on proton-proton collisions, obtained at the CERN Intersecting Storage Rings, in which two roughly back-to-back π⁰'s of high transverse momentum (p_T) were produced. The angular distribution of the dipion axis relative to the collision axis is found to be independent of both the effective mass m of the dipion system and the centre-of-mass energy √s of the proton-proton collision. The cross-sections $\text{d}\text{σ}\text{d}\text{m}$ at the values of √s satisfy a scaling law of the form $\text{d}\text{σ}\text{d}\text{m}\text{=}\text{G(x)}\text{m}{}^{\mathrm{n}}\text{,}\text{where}\text{x = m(π}{}^0\text{, π}{}^0\text{)//trs}\text{and}\text{n = 6.5 ± 0.5}$. We show from our data that the leading π⁰ carries most of the momentum of the scattered parton. Given this fact, the axis of the dipion system follows closely the direction of the scattered constituents, and we exploit this to determine the angular dependence of the hard-scattering subprocess. We also compare our data with the lowest order QCD predictions using structure functions as determined in deep-inelastic scattering and fragmentation functions from electron-positron annihilation.     

A proposed mechanisms for the transient suppression of bacterial luminescence by hydrogen peroxide

It has been shown previously that bacterial luminescence is reversibly suppressed in vivo and in vitro by both X-rays and hydrogen peroxide. The data presented here show that the mechanisms for this phenomenon is based on the transient oxidation of reduced flavin mononucleotide.     

Highly excited “nuclear molecules”: A way to explain the fluctuations in DBHIC excitation functions. Study of the28Si +28Si colliding system at 5.3 MeV ·A

The properties of the strong fluctuations observed in the excitation functions of Dissipative Binary Heavy Ion Collisions (DBHIC) have been studied for the system²⁸Si+²⁸Si in the energy range 150 MeV ≤E _lab ≤ 156 MeV with 150 keV step laboratory incident energy, by angular distributions and excitation functions measurements. Experimental results are compared to the the recently developed Partially Overlapping Molecular Level Model (POMLM). The parameters of the model have been determined with reasonable accuracy by describing all the quantities characterizing the fluctuations in the excitation functions i.e.: Average Angular Distributions, Energy Autocorrelation Functions, Variances, Angular Correlation Coefficients. The results of the analysis strongly support the idea of a process proceeding through the formation of an highly excited “nuclear molecule”. Experimental data collected at the most forward angles show the effects of strong excitation of a few final channels.