High Precision Particle Astrophysics as a New Window on the Universe An Antimatter Large Acceptance Detector In Orbit (ALADInO)
Abstract
During the last 25 years, the accuracy on the direct measurement of Cosmic Rays has greatly improved by a series of experiments like AMS-01, PAMELA, AGILE, FERMI, AMS-02, CALET and DAMPE. At present, the field of precison Cosmic Ray physics has reached a solid maturity and it is exhibiting a very interesting discovery potential complementary and competitive with ground based experiments like LHC at CERN or underground experiments like the one performed at the Gran Sasso Laboratory. Antimatter particles in Cosmic Rays (CR) represent a small fraction of the total flux, from 5×10-3 for e+, to less than 10-8 for anti-4He or heavier antinuclei. These tiny fluxes, however, carry a great amount of information, since the origin of antiparticles is intimately related to processes which might shed light on fundamental properties of matter, fundamental forces, astrophysics and cosmology. A first example is the observed Matter-Antimatter asymmetry, one of the greatest mistery of current cosmology: we have no evidence so far at ground experiments for a mechanism which could explain baryogenesis. At the same time, theories that either predict the existence of nuclear antimatter in segregated domains or its total absence in the current universe have no firm foundation in observational data. The unambiguous detection of anti-4He or heavier antinuclei in CRs would shatter our current understanding of early Universe physics with broad cosmological implications or reveal something completely unforeseen in the realm of astrophysics, such as e.g. an anomalous abundance of dense antibaryon stars or anti-cloudlets in our Galaxy. A second example is the nature of Dark Matter, which existence is well established and supported by a variety of astrophysical and cosmological observations. Its particle nature is still subject of exciting speculations. Since DM is abundant in the universe, particle astrophysics in space is the right environment for indirect searches of DM particles. Antiparticles (e+, p-, D-, anti-3He) constitute golden channels for this search, since the rare antiparticle component of DM annihilation/decay products, would give rise to an observable excess on these fluxes with respect to the tiny standard astrophysical expectations, not influenced by the otherwise large background for standard CR. In order to address the above-mentioned scientific questions we discuss a set of key requirements for a mission based on a large acceptance, superconducting magnetic spectrometer to separate charged particles/anti-particles (Antimatter Large Acceptance Detector In Orbit -ALADInO). A collection factor of ≈ 20 m2sr years is needed to increase by a factor 103 current limits on anti-4He or heavier nuclear anti-matter. A collection factor of ~15 m2 sr years, a maximum detectable rigidity of 20 TV and a e±/p± separation at the level of 106 are needed to provide a substantial progress in sensitivity to test the heavy-DM hypothesis to explain the structure observed by AMS-02 in the e+ flux. The same collection factor, together with a velocity measurement with 1% resolution, would allow for the measurement of O(1 GeV) anti-p, anti-D and anti-3He, in an energy range where DM models predict signals 1-2 orders of magnitude larger that the astrophysical background. Such a large collection factor would allow the study the light CR spectrum until the energy range E~1 Pev shedding light on the puzzle of the composition of extragalactig cosmic rays. The ALADInO project has been proposed to the VOYAGE 2035-2050 program for a new generation of space experiment to be developed after 203. In this talk ALADInO is discussed at level of concept, which can be implemented also through intermediate phases in order to test the more demanding technologies while addressing parts of the physics program.
- Publication:
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43rd COSPAR Scientific Assembly. Held 28 January - 4 February
- Pub Date:
- January 2021
- Bibcode:
- 2021cosp...43E1369B