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

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

Tidal streams from axion miniclusters and direct axion searches

In some axion dark matter models a dominant fraction of axions resides in dense small-scale substructures, axion miniclusters. A fraction of these substructures is disrupted and forms tidal streams where the axion density may still be an order of magnitude larger than the average. We discuss implications of these streams for the direct axion searches. We estimate the fraction of disrupted miniclusters and the parameters of the resulting streams, and find that stream-crossing events would occur at a rate of about $1/(20 {\rm yr})$ for 2-3 days, during which the signal in axion detectors would be amplified by a factor $\sim 10$. These estimates suggest that the effect of the tidal disruption of axion miniclusters may be important for direct axion searches and deserves a more thorough study.Comment: Replaced with the version accepted for publication in JCA

Solar X-rays as Signature for New Particles

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

A proposal to use CPLEAR as antigravitometer

The reconstructed kinematics of the isotropically emitted $K^0\overline{K}^0$ and their decay vertex following a $p\overline{p}$ annihilation at rest allows to select events with specific neutral kaon topology {\it and} energy. Thus, from the accumulated events with CPLEAR one can define high statistics subgroups of any gravitationally oriented neutral kaons with $\sim \pm 60$ cm maximum vertical displacement, in order to search for (anti)gravity effects. The suggested new data analysis allows to combine for the first time upward moving $K^0$'s with downward emitted $overline{K}^0$'s, and {\it vice versa}, in order to search for any directional dependence of the $CP$ parameters. The achieved limit for the relative $K^0-overline{K}^0$ mass difference ($\sim 10^{-18}$) may be indicative of a probably unique sensitivity for the proposed antigravity search. Existing anomalous energy dependent $CP$ results along with the used non-horizontal kaon beam (having in fact an equal vertical kaon displacement per $\tau_S$ as in CPLEAR) are in favour of this proposal whatever the theoretical interpretation

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

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 $E_{axion} \sim m_{axion}$, 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