297 research outputs found

    Constraints on Exotic Heavily Ionizing Particles from the Geological Abundance of Fullerenes

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    The C_{60} molecule exhibits a remarkable stability and inertness that leads to its survival in ancient carbonaceous rocks initially subject to the high temperatures requisite for its formation. Elementary particles having very high electronic stopping powers can similarly form C_{60} and higher fullerenes in their wake. Combined, these two features point at the possibility of using the C_{60} presence (or absence) in selected bulk geological samples as a new type of solid-state nuclear track detector, with applications in astro-particle physics.Comment: Final version (few modifications). Phys. Rev. Lett. (in press). 4 pages LaTeX, 1 eps figure embedde

    Solar X-rays as Signature for New Particles

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    Massive axions of the Kaluza-Klein type, created inside the solar core, can be gravitationally trapped by the Sun itself in orbits inside/outside the Sun, where they accumulate over cosmic times. Their radiative decay can give rise to various solar phenomena, like the celebrated solar coronal heating, which lacks a conventional explanation since its first observation in 1939. Such and other recent observations favour the existence of a halo of exotic particles near the Sun. X-ray telescopes can provide novel and important information. The underlying solar axion scenario is presented in details in ref.'s [4,15]Comment: 6 pages, TeX file, Proc. Results and Perspectives in Particle Physics, La Thuile (2004

    Running CAST 2008-2010

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    This document contains additional information to complement the request for additional running time 2008-2010 (CERN-SPSC-2007-012

    A Critique of Drexler Dark Matter

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    Drexler dark matter is an alternate approach to dark matter that assumes that highly relativistic protons trapped in the halo of the galaxies could account for the missing mass. We look at various energetics involved in such a scenario such as the energy required to produce such particles and the corresponding lifetimes. Also we look at the energy losses from synchrotron and inverse Compton scattering and their signatures. The Coulomb repulsive instability due to the excess charge around the galaxies is also calculated. The above results lead us to conclude that such a model for DM is unfeasible.Comment: 4 pages, 10 equation

    KWISP: an ultra-sensitive force sensor for the Dark Energy sector

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    An ultra-sensitive opto-mechanical force sensor has been built and tested in the optics laboratory at INFN Trieste. Its application to experiments in the Dark Energy sector, such as those for Chameleon-type WISPs, is particularly attractive, as it enables a search for their direct coupling to matter. We present here the main characteristics and the absolute force calibration of the KWISP (Kinetic WISP detection) sensor. It is based on a thin Si3N4 micro-membrane placed inside a Fabry-Perot optical cavity. By monitoring the cavity characteristic frequencies it is possible to detect the tiny membrane displacements caused by an applied force. Far from the mechanical resonant frequency of the membrane, the measured force sensitivity is 5.0e-14 N/sqrt(Hz), corresponding to a displacement sensitivity of 2.5e-15 m/sqrt(Hz), while near resonance the sensitivity is 1.5e-14 N/sqrt(Hz), reaching the estimated thermal limit, or, in terms of displacement, 7.5e-16 N/sqrt(Hz). These displacement sensitivities are comparable to those that can be achieved by large interferometric gravitational wave detectors.Comment: 9 pages, 8 figures in colo

    Guidelines for axion identification in astrophysical observations

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    The origin of various celestial phenomena have remained mysterious for conventional astrophysics. Therefore, alternative solutions should be considered, taking into account the involvement of unstable dark-matter particle candidates, such as the celebrated axions or other as yet unforeseen axion-like particles. Their spontaneous and induced decay by the ubiquitous solar magnetic fields can be at the origin of persisting enigmatic X-ray emission, giving rise to a steady and a transient/local solar activity, respectively. The (coherent) conversion of photons into axion(-like) particles in intrinsic magnetic fields may modify the solar axion spectrum. The reversed process can be behind transient (solar) luminosity deficits in the visible. Then, the Sun might be also a strong source of ~eV-axions. Thus, enigmatic observations might be the as yet missing direct signature for axion(-like) particles in earth-bound detectors.Comment: 6 pages, to be submitted to JCA

    Photon Production From The Scattering of Axions Out of a Solenoidal Magnetic Field

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    We calculate the total cross section for the production of photons from the scattering of axions by a strong inhomogeneous magnetic field in the form of a 2D delta-function, a cylindrical step function and a 2D Gaussian distribution, which can be approximately produced by a solenoidal current. The theoretical result is used to estimate the axion-photon conversion probability which could be expected in a reasonable experimental situation. The calculated conversion probabilities for QCD inspired axions are bigger by a factor of 2.67 (for the cylindrical step function case) than those derived by applying the celebrated 1D calculation of the (inverse) coherent Primakoff effect. We also consider scattering at a resonance Eaxion∌maxionE_{axion} \sim m_{axion}, which corresponds to the scattering from a delta-function and gives the most enhanced results. Finally, we analyze the results of this work in the astrophysical extension to suggest a way in which they may be directed to a solution to some basic solar physics problems and, in particular, the coronal heating problem.Comment: 19 pages, 1 figure, added analysis of our results in the astrophysical extensio