{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"03584fd45b58d180b8e3074be2f0d55a02bd8f34c6526ffd64dfc835ffc7ce0d","created":"2026-10-03T07:17:54Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"27dc5cbc460698b02675cae016af1b2ce13cb3e53a14465eecf8dac6349c36b0","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"identification","assisted_by":[],"external_id":"astro.cosmic-ray-antimatter.positron-excess","kind":"well-posed","literature_status":"contested","n":"1","parents":[],"plain":"There are more positrons, antimatter electrons, at high energies than collisions of ordinary cosmic rays with gas can make. Nearby pulsars or dark matter could supply them.","posed_since":"2009","precise":"The positron fraction e+/(e+ + e-) rises above about 10 GeV (PAMELA, AMS-02), and the AMS-02 positron flux shows a high-energy drop-off near several hundred GeV. Identify the dominant extra source (nearby pulsars and their wind nebulae, dark-matter annihilation or decay, or secondary production in sources) by fitting the spectrum, its cutoff and the upper limits on dipole anisotropy.","problem_ref":null,"references":"","settled_by":"Detection or exclusion of the anisotropy or spectral structure predicted for nearby pulsars, combined with TeV electron spectra and diffusion constraints near pulsars.","status_note":"TeV halos around Geminga and Monogem seen by HAWC show that pulsars release electron-positron pairs, but slow diffusion near them limits their contribution at Earth and the share remains debated.","title":"Pulsars or dark matter as the source of excess cosmic positrons","topic_ref":"9361a52640d12aea0c06eba8ab45c71de10728afb1ce58839faac9301aaf079e"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"0281362f87d8569b9fa4e9af3448394b2309a09be1b3228e7602a0d58c9c7b2c","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"d4392812d97ef87f8c03ec5ba79e9a8ba8b265b9f28fbc96cdf5f8fe9fccc8e2","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"PodeHZoYBrCRK7HhTMR0sNpa5MdXaYv-8Dj5UvqCXDQTw2bOecA4aXBuKKbytHL-qRXfH0P9_pIsA1EeNr55CQ"},"schema":"pubphys.envelope/1"},"record_hash":"0281362f87d8569b9fa4e9af3448394b2309a09be1b3228e7602a0d58c9c7b2c","leaf_index":509}