Combined analysis of AMS-02 (Li,Be,B)/C, N/O, 3He, and 4He data
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Combined analysis of AMS-02 (Li,Be,B)/C, N/O, 3He, and 4He data. / Weinrich, N.; Genolini, Y.; Boudaud, M.; Derome, L.; Maurin, D.
In: Astronomy & Astrophysics, Vol. 639, A131, 21.07.2020.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Combined analysis of AMS-02 (Li,Be,B)/C, N/O, 3He, and 4He data
AU - Weinrich, N.
AU - Genolini, Y.
AU - Boudaud, M.
AU - Derome, L.
AU - Maurin, D.
PY - 2020/7/21
Y1 - 2020/7/21
N2 - Context. The Alpha Magnetic Spectrometer (AMS-02) measured several secondary-to-primary ratios enabling a detailed study of Galactic cosmic-ray transport.Aims. We constrain previously derived benchmark scenarios (based on AMS-02 B/C data only) using other secondary-to-primary ratios to test the universality of transport and the presence of a low-rigidity diffusion break.Methods. We use the 1D thin disc/thick halo propagation model of USINE V3.5 and a chi(2) minimisation accounting for a covariance matrix of errors (AMS-02 systematics) and nuisance parameters (cross-sections and solar modulation uncertainties).Results. The combined analysis of AMS-02 Li/C, Be/C, and B/C strengthens the case for a diffusion slope of delta = 0.500.03 with a low-rigidity break or upturn of the diffusion coefficient at GV rigidities. Our simple model can successfully reproduce all considered data (Li/C, Be/C, B/C, N/O, and He-3/He-4), although several issues remain: (i) the quantitative agreement depends on the assumptions made on the poorly constrained correlation lengths of AMS-02 data systematics; (ii) combined analyses are very sensitive to production cross-sections, and we find post-fit values differing by similar to 5-15% from their most likely values (roughly within currently estimated nuclear uncertainties); (iii) two very distinct regions of the parameter space remain viable, either with reacceleration and convection, or with purely diffusive transport.Conclusions. To take full benefit of combined analyses of AMS-02 data, better nuclear data and a better handle on energy correlations in the data systematic are required. AMS-02 data on heavier species are eagerly awaited to explore cosmic-ray propagation scenarios further.
AB - Context. The Alpha Magnetic Spectrometer (AMS-02) measured several secondary-to-primary ratios enabling a detailed study of Galactic cosmic-ray transport.Aims. We constrain previously derived benchmark scenarios (based on AMS-02 B/C data only) using other secondary-to-primary ratios to test the universality of transport and the presence of a low-rigidity diffusion break.Methods. We use the 1D thin disc/thick halo propagation model of USINE V3.5 and a chi(2) minimisation accounting for a covariance matrix of errors (AMS-02 systematics) and nuisance parameters (cross-sections and solar modulation uncertainties).Results. The combined analysis of AMS-02 Li/C, Be/C, and B/C strengthens the case for a diffusion slope of delta = 0.500.03 with a low-rigidity break or upturn of the diffusion coefficient at GV rigidities. Our simple model can successfully reproduce all considered data (Li/C, Be/C, B/C, N/O, and He-3/He-4), although several issues remain: (i) the quantitative agreement depends on the assumptions made on the poorly constrained correlation lengths of AMS-02 data systematics; (ii) combined analyses are very sensitive to production cross-sections, and we find post-fit values differing by similar to 5-15% from their most likely values (roughly within currently estimated nuclear uncertainties); (iii) two very distinct regions of the parameter space remain viable, either with reacceleration and convection, or with purely diffusive transport.Conclusions. To take full benefit of combined analyses of AMS-02 data, better nuclear data and a better handle on energy correlations in the data systematic are required. AMS-02 data on heavier species are eagerly awaited to explore cosmic-ray propagation scenarios further.
KW - astroparticle physics
KW - cosmic rays
KW - COSMIC-RAY PROPAGATION
KW - ACCURATE UNIVERSAL PARAMETERIZATION
KW - PRODUCTION CROSS-SECTIONS
KW - LIQUID-HYDROGEN TARGET
KW - SOLAR MODULATION
KW - SUPERNOVA-REMNANTS
KW - NEUTRON MONITORS
KW - MUON DETECTORS
KW - NUCLEON BE-9
KW - REACCELERATION
U2 - 10.1051/0004-6361/202037875
DO - 10.1051/0004-6361/202037875
M3 - Journal article
VL - 639
JO - Astronomy & Astrophysics
JF - Astronomy & Astrophysics
SN - 0004-6361
M1 - A131
ER -
ID: 246780290