14 research outputs found
Cosmic-Ray Nuclei, Antiprotons and Gamma-rays in the Galaxy: a New Diffusion Model
We model the transport of cosmic ray nuclei in the Galaxy by means of a new
numerical code. Differently from previous numerical models we account for a
generic spatial distribution of the diffusion coefficient. We found that in the
case of radially uniform diffusion, the main secondary/primary ratios (B/C, N/O
and sub-Fe/Fe) and the modulated antiproton spectrum match consistently the
available observations. Convection and re-acceleration do not seem to be
required in the energy range we consider: GeV/nucleon. We
generalize these results accounting for radial dependence of the diffusion
coefficient, which is assumed to trace that of the cosmic ray sources. While
this does not affect the prediction of secondary/primary ratios, the simulated
longitude profile of the diffuse -ray emission is significantly
different from the uniform case and may agree with EGRET measurements without
invoking ad hoc assumptions on the galactic gas density distribution.Comment: 17 pages, 6 figures. v3: Added detailed references to nuclear
cross-section networ
Les Houches 2011: Physics at TeV Colliders New Physics Working Group Report
We present the activities of the "New Physics" working group for the "Physics
at TeV Colliders" workshop (Les Houches, France, 30 May-17 June, 2011). Our
report includes new agreements on formats for interfaces between computational
tools, new tool developments, important signatures for searches at the LHC,
recommendations for presentation of LHC search results, as well as additional
phenomenological studies.Comment: 243 pages, report of the Les Houches 2011 New Physics Group; fix
three figure
A Combined Interpretation of CR Nuclei and Antiproton High Energy Measurements
In the last months several ballon and satellite experiments improved
significantly our knowledge of cosmic rays (CR) spectra at high energy. In
particular CREAM allowed to measure B/C, C/O and N/O up to 1 TeV and PAMELA the
anti-p/p ratio up to 100 GeV with unprecedented accuracy. These measurements
offer a valuable probe of CR propagation properties. We performed a statistical
analysis to test the compatibility of these results, as well as other most
significant experimental data, with the predictions of a new numerical CR
diffusion package (DRAGON). We found that above 1 GeV all data are consistent
with a diffusion scenario in a well defined range of values of the diffusion
coefficient energy power index and normalization.Comment: 5 pages. To appear in the proceedings of 31th International Cosmic
Ray Conference (ICRC 2009), Lodz, Poland, 7-15 Jul 2009. v2: DESY report
number adde
A common solution to the cosmic ray anisotropy and gamma-ray gradient problems
International audienceMultichannel Cosmic Ray (CR) spectra and the large scale CR anisotropy canhardly be made compatible in the framework of conventional isotropic andhomogeneous propagation models. These models also have problems explaining thelongitude distribution and the radial emissivity gradient of the -raygalactic interstellar emission. We argue here that accounting for a wellphysically motivated correlation between the CR escape time and the spatiallydependent magnetic turbulence power can naturally solve both problems. Indeed,by exploiting this correlation we find propagation models that fit a wide setof CR primary and secondary spectra, and consistently reproduce the CRanisotropy in the energy range 10^2 - 10^4 \GeV and the -raylongitude distribution recently measured by Fermi-LAT
Unified interpretation of cosmic ray nuclei and antiproton recent measurements
We use our numerical code, DRAGON, to study the implications of recent data
on our knowledge of the propagation properties of cosmic ray nuclei in the
Galaxy. We show that B/C (as well as N/O and C/O) data, including those
recently taken by CREAM, and data, especially including recent
PAMELA results, can consistently be fitted within a unique
diffusion-reacceleration model. The requirement that light nuclei and
data are consistently reproduced within experimental uncertainties places
significant limits on the main propagation parameters. In particular, we find
the allowed range of the diffusion coefficient spectral index to be at 95% confidence level and that Kraichnan type diffusion is
favored with respect to Kolmogorov. While some amount of reacceleration is
required, only a limited range of the Alfv\'en velocity value (10 \simleq v_A
\simleq 20 \km \s^{-1}) is allowed by a combined analysis of nuclear and
antiproton data, which we perform here for the first time. If antiproton data
are not used to constrain the propagation parameters, a larger set of models is
allowed. In this case, we determine which combinations of the relevant
parameters maximize and minimize the antiproton flux under the condition of
still fitting light nuclei data at 95% C.L. These models may then be used to
constrain a possible extra antiproton component arising from astrophysical or
exotic sources (e.g. dark matter annihilation or decay).Comment: Final version accepted for publication in Astroparticle Physics. A
comparison with recently published PAMELA antiproton data is presented. 19
pages, 13 figures, 1 tabl
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Les Houches 2011: Physics at TeV Colliders New Physics Working Group Report
We present the activities of the "New Physics" working group for the "Physics
at TeV Colliders" workshop (Les Houches, France, 30 May-17 June, 2011). Our
report includes new agreements on formats for interfaces between computational
tools, new tool developments, important signatures for searches at the LHC,
recommendations for presentation of LHC search results, as well as additional
phenomenological studies