{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"a7b6e26d507e20f633103cd3697c67fd0be4197aae9c064457f5a4f7b549d1f3","created":"2026-10-03T07:18:08Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"2cfeb14dd7d5271da3fae7341a3955ed9b77a3d3d96a73f3e986f7859a0a8cf0","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"plasma.vacuum-birefringence-schwinger.tunneling-breit-wheeler","kind":"well-posed","literature_status":"open","n":"1","parents":[],"plain":"A $\\gamma$ ray colliding with a strong laser can turn into an electron-positron pair by quantum tunneling, the same process as Schwinger pair creation but in a moving frame. A 1997 experiment saw pair creation only in the weak-field regime, and the tunneling regime is still unobserved.","posed_since":"","precise":"Nonlinear Breit-Wheeler pair creation $\\gamma + n\\,\\omega_L \\to e+\\,e-$ in the regime $a0 >> 1$, $\\chi_\\gamma < 1$ has a rate proportional to $\\exp(-8/(3\\chi_\\gamma))$, the Schwinger-type tunneling exponent, where $\\chi_\\gamma \\sim 2\\left(\\hbar\\omega_\\gamma/(m c^2)\\right)\\left(E/E_S\\right)$ for head-on collisions. SLAC E144 (1997) observed only the multiphoton regime at $a0 \\sim 0.3$, where the yield scales as $a0^{2n}$. Determine whether experiments with $a0 >\\sim 1$ (LUXE at DESY, E-320 at SLAC FACET-II, or all-optical setups) measure the positron yield versus $a0\\text{ and }\\chi_\\gamma$ showing the transition from power-law to tunneling dependence, with absolute yields matching strong-field QED within stated uncertainties.","problem_ref":null,"references":"","settled_by":"A positron-yield scan versus laser intensity with calibrated gamma spectrum showing the $\\operatorname{exp}(-8/(3\\chi_{\\gamma}))$ dependence.","status_note":"No tunneling-regime pair data from LUXE (DESY) or E-320 (SLAC FACET-II) are known to this compilation as of 2026; E-320 status should be checked.","title":"Observation of tunneling pair creation in gamma-ray laser collisions","topic_ref":"55a07bba1dfa71f7b80f75c8b6d22d8d64b8456a647eee5719b5c98b8b9ea3c9"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"34e8ffef844ab12d1ea9768a811995a0e2aa6fbc6d46e3cf56d69735447a1912","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"b193b06b4ce5045c1075a5e53942716191c2dd9da2e8fe8fd5aed614f6c2768c","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"4TqyXNkIOgLvoVJ3OlBf5tsE0hYW5a69hU6ZfjkjS7S56eT1Sar3CVdc-q4Aymonb_da9QDl9aCQxAYhr7gSBw"},"schema":"pubphys.envelope/1"},"record_hash":"34e8ffef844ab12d1ea9768a811995a0e2aa6fbc6d46e3cf56d69735447a1912","leaf_index":1880}