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Pierre Auger Collaboration (Abreu, P. et al); Pastor, S. |
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Title |
The effect of the geomagnetic field on cosmic ray energy estimates and large scale anisotropy searches on data from the Pierre Auger Observatory |
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Journal Article |
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Year |
2011 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
11 |
Issue |
11 |
Pages  |
022 |
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Abstract |
We present a comprehensive study of the influence of the geomagnetic field on the energy estimation of extensive air showers with a zenith angle smaller than 60 degrees, detected at the Pierre Auger Observatory. the geomagnetic field induces an azimuthal modulation of the estimated energy of cosmic rays up to the similar to 2% level at large zenith angles. We present a method to account for this modulation of the reconstructed energy. We analyse the effect of the modulation on large scale anisotropy searches in the arrival direction distributions of cosmic rays. At a given energy, the geomagnetic effect is shown to induce a pseudo-dipolar pattern at the percent level in the declination distribution that needs to be accounted for. |
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ISSN |
1475-7516 |
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Notes |
WOS:000298141300022 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
865 |
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Author |
Andricek, L. et al; Lacasta, C.; Marinas, C.; Vos, M. |
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Title |
Intrinsic resolutions of DEPFET detector prototypes measured at beam tests |
Type |
Journal Article |
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Year |
2011 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
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Volume |
638 |
Issue |
1 |
Pages |
24-32 |
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Keywords |
Silicon pixel detector; Detector resolution; Spatial resolution; DEPFET; Beam test |
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Abstract |
The paper is based on the data of the 2009 DEPFET beam test at CERN SPS. The beam test used beams of pions and electrons with energies between 40 and 120 GeV, and the sensors tested were prototypes with thickness of 450 μm and pixel pitch between 20 and 32 μm. Intrinsic resolutions of the detectors are calculated by disentangling the contributions of measurement errors and multiple scattering in tracking residuals. Properties of the intrinsic resolution estimates and factors that influence them are discussed. For the DEPFET detectors in the beam test, the calculation yields intrinsic resolutions of approximate to 1 μm, with a typical accuracy of 0.1 μm. Bias scan, angle scan, and energy scan are used as example studies to show that the intrinsic resolutions are a useful tool in studies of detector properties. With sufficiently precise telescopes, detailed resolution maps can be constructed and used to study and optimize detector performance. |
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Address |
[Dolezal, Z.; Drasal, Z.; Kodys, P.; Kvasnicka, P.; Malina, L.; Scheirich, J.] Charles Univ Prague, Fac Math & Phys, Inst Particle & Nucl Phys, CR-18000 Prague, Czech Republic, Email: peter.kodys@mff.cuni.cz |
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Elsevier Science Bv |
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English |
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ISSN |
0168-9002 |
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Notes |
ISI:000290082600005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
618 |
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Author |
Villaescusa-Navarro, F.; Dalal, N. |
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Title |
Cores and cusps in warm dark matter halos |
Type |
Journal Article |
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Year |
2011 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
03 |
Issue |
3 |
Pages |
024 - 16pp |
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Keywords |
dark matter theory; dark matter simulations; dwarfs galaxies; rotation curves of galaxies |
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Abstract |
The apparent presence of large core radii in Low Surface Brightness galaxies has been claimed as evidence in favor of warm dark matter. Here we show that WDM halos do not have cores that are large fractions of the halo size: typically, r(core)/r(200) less than or similar to 10(-3). This suggests an astrophysical origin for the large cores observed in these galaxies, as has been argued by other authors. |
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[Villaescusa-Navarro, Francisco] Univ Valencia, CSIC, IFIC, E-46071 Valencia, Spain, Email: villa@ific.uv.es |
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Iop Publishing Ltd |
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English |
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ISSN |
1475-7516 |
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Conference |
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Notes |
ISI:000291258300024 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
641 |
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Author |
Serenelli, A.M.; Haxton, W.C.; Pena-Garay, C. |
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Title |
Solar Models With Accretion. I. Application To The Solar Abundance Problem |
Type |
Journal Article |
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Year |
2011 |
Publication |
Astrophysical Journal |
Abbreviated Journal |
Astrophys. J. |
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Volume |
743 |
Issue |
1 |
Pages |
24 - 20pp |
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Keywords |
accretion, accretion disks; neutrinos; Sun: abundances; Sun: helioseismology; Sun: interior |
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Abstract |
We generate new standard solar models using newly analyzed nuclear fusion cross sections and present results for helioseismic quantities and solar neutrino fluxes. The status of the solar abundance problem is discussed. We investigate whether nonstandard solar models with accretion from the protoplanetary disk might alleviate this problem. We examine a broad range of models, analyzing metal-enriched and metal-depleted accretion and three scenarios for the timing of accretion. Only partial solutions are found. Formetal-rich accreted material (Z(ac) greater than or similar to 0.018) there exist combinations of accreted mass and metallicity that bring the depth of the convective zone into agreement with the helioseismic value. For the surface helium abundance, the helioseismic value is reproduced if metal-poor or metal-free accretion is assumed (Z(ac) less than or similar to 0.09). In both cases a few percent of the solar mass must be accreted. Precise values depend on when accretion takes place. We do not find a simultaneous solution to both problems but speculate that changing the hydrogen-to-helium mass ratio in the accreted material may lead to more satisfactory solutions. We also show that, with current data, solar neutrinos are already a very competitive source of information about the solar core and can help constraining possible accretion histories. Even without helioseismic constraints, solar neutrinos rule out the possibility that more than 0.02 M(circle dot) from the protoplanetary disk were accreted after the Sun settled on the main sequence. Finally, we discuss how measurements of neutrinos from the CN cycle could shed light on the interaction between the early Sun and its protoplanetary disk. |
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Address |
[Serenelli, Aldo M.] Fac Ciencias, CSIC IEEC, Inst Ciencias Espacio, Bellaterra 08193, Spain |
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Publisher |
Iop Publishing Ltd |
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English |
Summary Language |
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0004-637x |
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Notes |
WOS:000297408300024 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
857 |
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Author |
Abgrall, N. et al; Cervera-Villanueva, A.; Escudero, L.; Monfregola, L.; Stamoulis, P. |
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Title |
Time projection chambers for the T2K near detectors |
Type |
Journal Article |
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Year |
2011 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
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Volume |
637 |
Issue |
1 |
Pages |
25-46 |
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Keywords |
Time projection chamber; Drift chamber; Gas system; Micromegas; Neutrino oscillation |
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Abstract |
The T2K experiment is designed to study neutrino oscillation properties by directing a high intensity neutrino beam produced at J-PARC in Tokai, Japan, towards the large Super-Kamiokande detector located 295 km away, in Kamioka, Japan. The experiment includes a sophisticated near detector complex, 280 m downstream of the neutrino production target in order to measure the properties of the neutrino beam and to better understand neutrino interactions at the energy scale below a few GeV. A key element of the near detectors is the ND280 tracker, consisting of two active scintillator-bar target systems surrounded by three large time projection chambers (TPCs) for charged particle tracking. The data collected with the tracker are used to study charged current neutrino interaction rates and kinematics prior to oscillation, in order to reduce uncertainties in the oscillation measurements by the far detector. The tracker is surrounded by the former UA1/NOMAD dipole magnet and the TPCs measure the charges, momenta, and particle types of charged particles passing through them. Novel features of the TPC design include its rectangular box layout constructed from composite panels, the use of bulk micromegas detectors for gas amplification, electronics readout based on a new ASIC, and a photoelectron calibration system. This paper describes the design and construction of the TPCs, the micromegas modules, the readout electronics, the gas handling system, and shows the performance of the TPCs as deduced from measurements with particle beams, cosmic rays, and the calibration system. |
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Address |
[Birney, P.; Bojechko, C.; Fransham, K.; Gaudin, A.; Karlen, D.; Langstaff, R.; Lenckowski, M.; Myslik, J.; Poffenberger, P.; Roney, M.; Tvaskis, V.] Univ Victoria, Dept Phys & Astron, Victoria, BC, Canada, Email: karlen@uvic.ca |
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Corporate Author |
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Thesis |
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Publisher |
Elsevier Science Bv |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0168-9002 |
ISBN |
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Conference |
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Notes |
ISI:000289608000004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
607 |
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| Permanent link to this record |
