375 research outputs found
Search for dark photons as candidates for Dark Matter with FUNK
An additional U(1) symmetry predicted in theories beyond the Standard Model of particle physics can give rise to hidden (dark) photons. Depending on the mass and density of these hidden photons, they could account for a large fraction of the Dark Matter observed in the Universe. When passing through an interface of materials with different dielectric properties, hidden photons are expected to produce a tiny flux of photons. The wavelength of these photons is directly related to the mass of the hidden photons. In this contribution we report on measurements covering the visible and near-UV spectrum, corresponding to a dark photon mass in the eV range. The data were taken with the FUNK experiment using a spherical mirror of ~14m2 total area built up of 36 aluminum segments
First results of the air shower experiment KASCADE
The main goals of the KASCADE (KArlsruhe Shower Core and Array DEtector)
experiment are the determination of the energy spectrum and elemental
composition of the charged cosmic rays in the energy range around the knee at
ca. 5 PeV. Due to the large number of measured observables per single shower a
variety of different approaches are applied to the data, preferably on an
event-by-event basis. First results are presented and the influence of the
high-energy interaction models underlying the analyses is discussed.Comment: 3 pages, 3 figures included, to appear in the TAUP 99 Proceedings,
Nucl. Phys. B (Proc. Suppl.), ed. by M. Froissart, J. Dumarchez and D.
Vignau
2008-2009 President\u27s Report
The Linfield College President\u27s Annual Report is a collection of information about the year in review, including academics, student life and athletics, enrollment, finances, philanthropy, and leadership
Electron, Muon, and Hadron Lateral Distributions Measured in Air-Showers by the KASCADE Experiment
Measurements of electron, muon, and hadron lateral distributions of extensive
air showers as recorded by the KASCADE experiment are presented. The data cover
the energy range from about 5x10^14 eV up to almost 10^17 eV and extend from
the inner core region to distances of 200 m. The electron and muon
distributions are corrected for mutual contaminations by taking into account
the detector properties in the experiment. All distributions are well described
by NKG-functions. The scale radii describing the electron and hadron data best
are approx. 30 m and 10 m, respectively. We discuss the correlation between
scale radii and `age' parameter as well as their dependence on shower size,
zenith angle, and particle energy threshold.Comment: 28 pages, 14 figures, Accepted for publication in Astroparticle
Physic
Dissecting the knee - Air shower measurements with KASCADE
Recent results of the KASCADE air shower experiment are presented in order to
shed some light on the astrophysics of cosmic rays in the region of the knee in
the energy spectrum. The results include investigations of high-energy
interactions in the atmosphere, the analysis of the arrival directions of
cosmic rays, the determination of the mean logarithmic mass, and the unfolding
of energy spectra for elemental groups
KASCADE: Astrophysical results and tests of hadronic interaction models
KASCADE is a multi-detector setup to get redundant information on single air
shower basis. The information is used to perform multiparameter analyses to
solve the threefold problem of the reconstruction of (i)the unknown primary
energy, (ii) the primary mass, and (iii) to quantify the characteristics of the
hadronic interactions in the air-shower development. In this talk recent
results of the KASCADE data analyses are summarized concerning cosmic ray
anisotropy studies, determination of flux spectra for different primary mass
groups, and approaches to test hadronic interaction models. Neither large scale
anisotropies nor point sources were found in the KASCADE data set. The energy
spectra of the light element groups result in a knee-like bending and a
steepening above the knee. The topology of the individual knee positions shows
a dependency on the primary particle. Though no hadronic interaction model is
fully able to describe the multi-parameter data of KASCADE consistently, the
more recent models or improved versions of older models reproduce the data
better than few years ago.Comment: to appear in Nucl. Phys. B (Proc. Suppl.), Proc. of the XIII
ISVHECRI, Pylos 2004 - with a better quality of the figure
Cosmic Ray Energy Spectra and Mass Composition at the Knee - Recent Results from KASCADE -
Recent results from the KASCADE experiment on measurements of cosmic rays in
the energy range of the knee are presented. Emphasis is placed on energy
spectra of individual mass groups as obtained from an two-dimensional unfolding
applied to the reconstructed electron and truncated muon numbers of each
individual EAS. The data show a knee-like structure in the energy spectra of
light primaries (p, He, C) and an increasing dominance of heavy ones (A > 20)
towards higher energies. This basic result is robust against uncertainties of
the applied interaction models QGSJET and SIBYLL which are used in the shower
simulations to analyse the data. Slight differences observed between
experimental data and EAS simulations provide important clues for further
improvements of the interaction models. The data are complemented by new limits
on global anisotropies in the arrival directions of CRs and by upper limits on
point sources. Astrophysical implications for discriminating models of maximum
acceleration energy vs galactic diffusion/drift models of the knee are
discussed based on this data.Comment: 8 pages, 7 figures, to appear in Nuclear Physics B, Proceedings
Supplements, as part of the volume for the CRIS 2004, Cosmic Ray
International Seminar: GZK and Surrounding
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