Compatibility of CAST search with axion-like interpretation of PVLAS results

The PVLAS collaboration has results that may be interpreted in terms of a light axion-like particle, while the CAST collaboration has not found any signal of such particles. We propose a particle physics model with paraphotons and with a low energy scale in which this apparent inconsistency is circumvented.Comment: 10 pages, 3 figures, version accepted for publication in Physical Review Letter

Neutrino and axion bounds from the globular cluster M5 (NGC 5904)

The red-giant branch (RGB) in globular clusters is extended to larger brightness if the degenerate helium core loses too much energy in "dark channels." Based on a large set of archival observations, we provide high-precision photometry for the Galactic globular cluster M5 (NGC 5904), allowing for a detailed comparison between the observed tip of the RGB with predictions based on contemporary stellar evolution theory. In particular, we derive 95% confidence limits of $g_{ae}<4.3\times10^{-13}$ on the axion-electron coupling and $\mu_\nu<4.5\times10^{-12}\,\mu_{\rm B}$ (Bohr magneton $\mu_{\rm B}=e/2m_e$) on a neutrino dipole moment, based on a detailed analysis of statistical and systematic uncertainties. The cluster distance is the single largest source of uncertainty and can be improved in the future.Comment: 5 pages, 2 figures, accepted for publication in Physical Review Letter

Invasive maxillary sinus aspergillosis: a case report successfully treated with voriconazole and surgical debridement

Introduction: Invasive aspergillosis of the paranasal sinuses is a rare disease and often misdiagnosed; however, its incidence has seen substancial growth over the past 2 decades. Definitive diagnosis of these lesions is based on histological examination and fungal culture. Case Report: An 81-year-old woman with a history of pain in the left maxillary region is presented. The diagnosis was invasive maxillary aspergillosis in immunocompetent patient, which was successfully treated with voricona - zole and surgical debridement. Possible clinical manifestations, diagnostic imaging techniques and treatment used are discussed. Since the introduction of voriconazole, there have been several reports of patients with invasive aspergillosis who responded to treatment with this new antifungal agent. Conclusions: We report the importance of early diagnosis and selection of an appropriate antifungal agent to achie - ve a successful treatment

Self Interacting Dark Matter in the Solar System

Weakly coupled, almost massless, spin 0 particles have been predicted by many extensions of the standard model of particle physics. Recently, the PVLAS group observed a rotation of polarization of electromagnetic waves in vacuum in the presence of transverse magnetic field. This phenomenon is best explained by the existence of a weakly coupled light pseudoscalar particle. However, the coupling required by this experiment is much larger than the conventional astrophysical limits. Here we consider a hypothetical self-interacting pseudoscalar particle which couples weakly with visible matter. Assuming that these pseudoscalars pervade the galaxy, we show that the solar limits on the pseudoscalar-photon coupling can be evaded.Comment: 17 pages, 2 figure

From Walrasian oligopolies to natural monopolyan: An evolutionary model of market structure

We study a market for a homogeneous good in which firms adjust theirproduction decisions on the basis of imitation, learning from own experience, and local experimentation.For any fixed set of firms (more than one), long run behavior settles on a symmetric marginal-cost pricingequlibrium. When market entry and exit are allowed, we find a sharp effect of technology onlongrun market structure. Specifically, we show that, under decreasing returns and some fixed cost,the market grows to full capacity at Walrasian equlibrium; on the other hand, if returns areincreasing, the unique long run outcome involves a profit-maximizing monopolist.Imitation, evolution, mutation

Open Heavy Flavor Production in QCD -- Conceptual Framework and Implementation Issues

Heavy flavor production is an important QCD process both in its own right and as a key component of precision global QCD analysis. Apparent disagreements between fixed-flavor scheme calculations of b-production rate with experimental measurements in hadro-, lepto-, and photo-production provide new impetus to a thorough examination of the theory and phenomenology of this process. We review existing methods of calculation, and place them in the context of the general PQCD framework of Collins. A distinction is drawn between scheme dependence and implementation issues related to quark mass effects near threshold. We point out a so far overlooked kinematic constraint on the threshold behavior, which greatly simplifies the variable flavor number scheme. It obviates the need for the elaborate existing prescriptions, and leads to robust predictions. It can facilitate the study of current issues on heavy flavor production as well as precision global QCD analysis.Comment: 13 pages, 10 figures, Proceedings of Ringberg Workshop: New Trends in HERA Physics 2001, Munich, German

Eternal binaries

The two-body problem is extensively studied in open systems and asymptotically flat spacetimes. However, there are many systems where radiation is trapped: they range from radiating charges in cavities to low-energy excitations of massive degrees of freedom, to anti-de Sitter spacetimes. Here, we study the problem of motion of a pointlike particle orbiting a massive compact object inside a cavity. We first show that - assuming circular motion - there are initial conditions for which the self-force vanishes and the binary is eternal. We then consider the evolution of the system under radiation reaction in a toy model which we argue captures the essentials of orbiting particles. We show that eternal circular binaries may exist. We also show that the presence of cavity modes leads to chaos in regimes of strong coupling or when the system is initialized close enough to a resonance. Our results have implications for physics in anti-de Sitter spacetimes and possibly for binaries evolving within dark matter haloes, if it consists on massive fundamental fields.Comment: 21 pages, 17 figure