Search of low-dimensional magnetics on the basis of structural data: spin-1/2 antiferromagnetic zigzag chain compounds In2VO5, beta-Sr(VOAsO4)2,(NH4,K)2VOF4 and alpha-ZnV3O8

A new technique for searching low-dimensional compounds on the basis of structural data is presented. The sign and strength of all magnetic couplings at distances up to 12 A in five predicted new antiferromagnetic zigzag spin-1/2 chain compounds In2VO5, beta-Sr(VOAsO4)2, (NH4)2VOF4, K2VOF4 and alpha-ZnV3O8 were calculated. It was stated that in the compound In2VO5 zigzag spin chains are frustrated, since the ratio (J2/J1) of competing antiferromagnetic (AF) nearest- (J1) and AF next-to-nearest-neighbour (J2) couplings is equal to 1.68 that exceeds the Majumdar-Ghosh point by 1/2. In other compounds the zigzag spin chains are AF magnetically ordered single chains as value of ratios J2/J1 is close to zero. The interchain couplings were analyzed in detail.Comment: 14 pages, 6 figure, 1 table, minor change

Physics Reach of High-Energy and High-Statistics IceCube Atmospheric Neutrino Data

This paper investigates the physics reach of the IceCube neutrino detector when it will have collected a data set of order one million atmospheric neutrinos with energies in the 0.1 \sim 10^4 TeV range. The paper consists of three parts. We first demonstrate how to simulate the detector performance using relatively simple analytic methods. Because of the high energies of the neutrinos, their oscillations, propagation in the Earth and regeneration due to \tau decay must be treated in a coherent way. We set up the formalism to do this and discuss the implications. In a final section we apply the methods developed to evaluate the potential of IceCube to study new physics beyond neutrino oscillations. Not surprisingly, because of the increased energy and statistics over present experiments, existing bounds on violations of the equivalence principle and of Lorentz invariance can be improved by over two orders of magnitude. The methods developed can be readily applied to other non-conventional physics associated with neutrinos.Comment: 21 pages, 7 figures, Revtex

Radiography of the Earth's Core and Mantle with Atmospheric Neutrinos

A measurement of the absorption of neutrinos with energies in excess of 10 TeV when traversing the Earth is capable of revealing its density distribution. Unfortunately, the existence of beams with sufficient luminosity for the task has been ruled out by the AMANDA South Pole neutrino telescope. In this letter we point out that, with the advent of second-generation kilometer-scale neutrino detectors, the idea of studying the internal structure of the Earth may be revived using atmospheric neutrinos instead.Comment: 4 pages, LaTeX file using RevTEX4, 2 figures and 1 table included. Matches published versio

Signatures of cosmic tau-neutrinos

The importance and signatures of cosmic tau--(anti)neutrinos have been studied for upward-- and downward--going $\mu^-+\mu^+$ and hadronic shower event rates relevant for present and future underground water or ice detectors, utilizing the unique and reliable ultrasmall--$x$ predictions of the dynamical (radiative) parton model. The upward--going $\mu^- +\mu^+$ event rates calculated just from cosmic $\nu_{\mu}+\bar{\nu}_{\mu}$ fluxes are sizeably enhanced by taking into account cosmic $\nu_{\tau}+ \bar{\nu}_{\tau}$ fluxes and their associated $\tau^- +\tau^+$ fluxes as well. The coupled transport equations for the upward--going $\stackrel{(-)}{\nu}_{\tau}$ flux traversing the Earth imply an enhancement of the attenuated and regenerated $\stackrel{(-)}{\nu}_{\tau}$ flux typically around $10^4-10^5$ GeV with respect to the initial cosmic flux. This enhancement turns out to be smaller than obtained so far, in particular for flatter initial cosmic fluxes behaving like $E_{\nu}^{-1}$. Downward--going $\mu^- +\mu^+$ events and in particular the background--free and unique hadronic `double bang' and `lollipop' events allow to test downward--going cosmic $\nu_{\tau} +\bar{\nu}_{\tau}$ fluxes up to about $10^9$ GeV.Comment: 32 pages, 6 figures; Added reference

Prompt neutrino fluxes from atmospheric charm

We calculate the prompt neutrino flux from atmospheric charm production by cosmic rays, using the dipole picture in a perturbative QCD framework, which incorporates the parton saturation effects present at high energies. We compare our results with the next-to-leading order perturbative QCD result and find that saturation effects are large for neutrino energies above 10^6 GeV, leading to a substantial suppression of the prompt neutrino flux. We comment on the range of prompt neutrino fluxes due to theoretical uncertainties.Comment: 13 pages with 11 figures; expanded discussion, added references, version to be published in Phys. Rev.