"Discrepant hardenings" in cosmic ray spectra: a first estimate of the effects on secondary antiproton and diffuse gamma-ray yields

Recent data from CREAM seem to confirm early suggestions that primary cosmic ray (CR) spectra at few TeV/nucleon are harder than in the 10-100 GeV range. Also, helium and heavier nuclei spectra appear systematically harder than the proton fluxes at corresponding energies. We note here that if the measurements reflect intrinsic features in the interstellar fluxes (as opposed to local effects) appreciable modifications are expected in the sub-TeV range for the secondary yields, such as antiprotons and diffuse gamma-rays. Presently, the ignorance on the origin of the features represents a systematic error in the extraction of astrophysical parameters as well as for background estimates for indirect dark matter searches. We find that the spectral modifications are appreciable above 100 GeV, and can be responsible for ~30% effects for antiprotons at energies close to 1 TeV or for gamma's at energies close to 300 GeV, compared to currently considered predictions based on simple extrapolation of input fluxes from low energy data. Alternatively, if the feature originates from local sources, uncorrelated spectral changes might show up in antiproton and high-energy gamma-rays, with the latter ones likely dependent from the line-of-sight.Comment: 6 pages, 3 figures. Clarifications and references added, conclusions unchanged. Matches published versio

Accessible interactive digital signage for visually impaired

In this workshop we discuss the potential of cross-modal haptic-auditory feedback for empowering visually impaired people to experience Interactive Digital Signage

Evaluation of the infrared test method for the olympus thermal balance tests

The performance of the infrared (IR) rig used for the thermal balance testing of the Olympus S/C thermal model is discussed. Included in this evaluation are the rig effects themselves, the IRFLUX computer code used to predict the radiation inputs, the Monitored Background Radiometers (MBR's) developed to measure the absorbed radiation flux intensity, the Uniform Temperature Reference (UTR) based temperature measurement system and the data acquisition system. A preliminary set of verification tests were performed on a 1 m x 1 m zone to assess the performance of the IR lamps, calrods, MBR's and aluminized baffles. The results were used, in part, to obtain some empirical data required for the IRFLUX code. This data included lamp and calrod characteristics, the absorptance function for various surface types, and the baffle reflectivities

New results on source and diffusion spectral features of Galactic cosmic rays: I- B/C ratio

In a previous study (Maurin et al., 2001), we explored the set of parameters describing diffusive propagation of cosmic rays (galactic convection, reacceleration, halo thickness, spectral index and normalization of the diffusion coefficient), and we identified those giving a good fit to the measured B/C ratio. This study is now extended to take into account a sixth free parameter, namely the spectral index of sources. We use an updated version of our code where the reacceleration term comes from standard minimal reacceleration models. The goal of this paper is to present a general view of the evolution of the goodness of fit to B/C data with the propagation parameters. In particular, we find that, unlike the well accepted picture, and in accordance with our previous study, a Kolmogorov-like power spectrum for diffusion is strongly disfavored. Rather, the $\chi^2$ analysis points towards $\delta\gtrsim 0.7$ along with source spectra index $\lesssim 2.0$. Two distinct energy dependences are used for the source spectra: the usual power-law in rigidity and a law modified at low energy, the second choice being only slightly preferred. We also show that the results are not much affected by a different choice for the diffusion scheme. Finally, we compare our findings to recent works, using other propagation models. This study will be further refined in a companion paper, focusing on the fluxes of cosmic ray nuclei.Comment: 32 pages, 13 figures, accepted in A&

Constraints on WIMP Dark Matter from the High Energy PAMELA pˉ/p\bar{p}/p data

A new calculation of the $\bar{p}/p$ ratio in cosmic rays is compared to the recent PAMELA data. The good match up to 100 GeV allows to set constraints on exotic contributions from thermal WIMP dark matter candidates. We derive stringent limits on possible enhancements of the WIMP \pbar flux: a $m_{\rm WIMP}$=100 GeV (1 TeV) signal cannot be increased by more than a factor 6 (40) without overrunning PAMELA data. Annihilation through the $W^+W^-$ channel is also inspected and cross-checked with $e^+/(e^-+e^+)$ data. This scenario is strongly disfavored as it fails to simultaneously reproduce positron and antiproton measurements.Comment: 5 pages, 5 figures, the bibliography has been updated, minor modifications have been made in the tex