First Results from Photon Multiplicity Detector at RHIC

We present the first measurement of multiplicity and pseudorapidity distributions of photons in the pseudorapidity region 2.3 < eta < 3.7 for different centralities in Au + Au collisions at sqrt{s_NN} = 62.4 GeV. The pseudorapidity distribution of photons, dominated by neutral pion decays, has been compared to those of identified charged pions, photons, and inclusive charged particles from heavy ion and nucleon-nucleon collisions at various energies. Scaling of photon yield with number of participating nucleons and limiting fragmentation scenario for inclusive photon production has been studied.Comment: Talk given at 5th International Conference on Physics and Astrophysics of Quark Gluon Plasma (February 8 - 12, 2005); 4 pages and 6 figure

Recent results of the STAR high-energy polarized proton-proton program at RHIC at BNL

The STAR experiment at the Relativistic Heavy-Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) is carrying out a spin physics program colliding transverse or longitudinal polarized proton beams at $\sqrt{s}=200-500$GeV to gain a deeper insight into the spin structure and dynamics of the proton. These studies provide fundamental tests of Quantum Chromodynamics (QCD). One of the main objectives of the STAR spin physics program is the determination of the polarized gluon distribution function through a measurement of the longitudinal double-spin asymmetry, $A_{LL}$, for various processes. Recent results will be shown on the measurement of $A_{LL}$ for inclusive jet production, neutral pion production and charged pion production at $\sqrt{s}=200$GeV. In addition to these measurements involving longitudinal polarized proton beams, the STAR collaboration has performed several important measurements employing transverse polarized proton beams. New results on the measurement of the transverse single-spin asymmetry, $A_{N}$, for forward neutral pion production and the first measurement of $A_{N}$ for mid-rapidity di-jet production will be discussed.Comment: 8 pages, 5 figures, Invited talk given at the 17th International Spin Physics Symposium (SPIN 2006), October 2006, Kyoto, Japa

Morsures, piqûres et empoisonnements dans l’Histoire Naturelle de Pline l’Ancien

This article aims to explain the large amount of space devoted by Pliny in his Natural History to remedies for the effects of bites and poisonous substances. Pliny is a compiler and reports a medical tradition known from the Alexandrian age. The interest of Pliny and other authors in this matter reflects a fear arising especially from two causes : on the one hand, the discovery by Greeks and Romans of Asian and African venomous animals ; on the other hand, the poisons used since Hellenistic times for criminal purposes. There are, however, other factors directly linked to Pliny’s life and beliefs : the use – and abuse – of poison in Nero’s time, the theme of the serpent in contemporary literature, and, above all, Pliny’s adherence to the doctrine of ‘sympathies’ and ‘antipathies’. In holding this point of view, Pliny has been influenced profoundly by a Pseudo-Democritus, Bolos of Mendes, the author of a lost book On Sympathies and Antipathies, with extensive discussion of magic, an art associating knowledge of animals, poisons and their remedies

Properties of particle production at large transverse momentum in Au+Au and Cu+Cu collisions at RHIC

We present the incident energy and system size dependence of the pT spectra for charged pions, protons, and anti-protons using Au+Au and Cu+Cu collisions at Sqrt(sNN) = 62.4 and 200 GeV in STAR experiment at RHIC. Through these measurements in the pT range of 0.2 < pT < 10 GeV/c we conduct a systematic study of the beam energy, system size and particle species dependence of nuclear modification factors and address specific predictions from the quark coalescence models regarding the beam energy dependence of baryon enhancement in the intermediate pT (2 < pT < 6 GeV/c) region.Comment: Talk given at 19th International Conference on Ultra-relativistic Nucleus-Nucleus Collisions: Quark Matter 2006 (QM 2006), Shanghai, China, 14-20 Nov. 200

New approach to nonlinear electrodynamics: dualities as symmetries of interaction

We elaborate on the duality-symmetric nonlinear electrodynamics in a new formulation with auxiliary tensor fields. The Maxwell field strength appears only in bilinear terms of the corresponding generic Lagrangian, while the self-interaction is presented by a function E depending on the auxiliary fields. Two types of dualities inherent in the nonlinear electrodynamics models admit a simple off-shell characterization in terms of this function. In the standard formulation, the continuous U(1) duality symmetry is nonlinearly realized on the Maxwell field strength. In the new setting, the same symmetry acts as linear U(1) transformations of the auxiliary field variables. The nonlinear U(1) duality condition proves to be equivalent to the linear U(1) invariance of the self-interaction E. The discrete self-duality (or self-duality by Legendre transformation) amounts to a weaker reflection symmetry of E. For a class of duality- symmetric Lagrangians we introduce an alternative representation with the auxiliary scalar field and find new explicit examples of such systems.Comment: Latex file, 21 page

Role of non-mantle CO2 in the dynamics of volcano degassing: The Mount Vesuvius example

International audienceMount Vesuvius, Italy, quiescent since A. D. 1944, is a dangerous volcano currently characterized by elevated CO2 emissions of debated origin. We show that such emissions are most likely the surface manifestation of the deep intrusion of alkalic-basaltic magma into the sedimentary carbonate basement, accompanied by sidewall assimilation and CO2 volatilization. During the last eruptive period (1631-1944), the carbonate-sourced CO2 made up 4.7-5.3 wt% of the vented magma. On a yearly basis, the resulting CO2 production rate is comparable to CO2 emissions currently measured in the volcanic area. The chemical and isotopic composition of the fumaroles supports the predominance of this crust-derived CO2 in volatile emissions at Mount Vesuvius

Comment on "Hara's theorem in the constituent quark model"

It is pointed out that current conservation alone does not suffice to prove Hara's theorem as it was claimed recently. By explicit calculation we show that the additional implicit assumption made in such "proofs" is that of a sufficiently localized current.Comment: 8 pages, Late

Lepton-Flavour Violation in Ordinary and Supersymmetric Grand Unified Theories

By an explicit calculation we show that in ordinary SU(5) logarithmic divergence in the amplitude of $\mu \to e\gamma$ cancels among diagrams and remaining finite part is suppressed by at least $1/M_{GUT}^2$. In SUSY SU(5), when the effect of flavour changing wave function renormalization is taken into account such logarithmic correction disappears, provided a condition is met among SUSY breaking masses. In SUGRA-inspired SUSY GUT the remaining logarithmic effect is argued not to be taken as a prediction of the theory.Comment: 8 pages, LaTeX209 file, using axodraw.st