Jul 12 – 23, 2021
Europe/Berlin timezone

The Zettavolt Askaryan Polarimeter (ZAP) mission concept: radio detection of ultra-high energy cosmic rays in low lunar orbit.

Jul 13, 2021, 6:00 PM
1h 30m


Talk CRI | Cosmic Ray Indirect Discussion


Andres Romero-Wolf (Jet Propulsion Laboratory, California Institute of Technology)


Probing the ultra-high energy cosmic ray (UHECR) spectrum beyond the cutoff at ~40 EeV requires an observatory with an acceptance that is impractical to achieve with ground arrays. We present a concept, designated the Zettavolt Askaryan Polarimeter (ZAP), for radio detection of UHECRs impacting the Moon’s regolith from low-lunar orbit. ZAP would observe several thousands of events above the cutoff (~40 EeV) with a full-sky field of view to test whether UHECRs originate from Starburst Galaxies, Active Galactic Nuclei, or other sources associated with the matter distribution of the local universe at a distance > 1 MPc. The unprecedented sensitivity of ZAP to energies beyond 100 EeV would enable a test of source acceleration mechanisms. At higher energies, ZAP would produce the most stringent limits on super heavy dark matter (SHDM) via limits on neutrinos and gamma rays resulting from self-annihilation or decay.


radio detection; ultra-high energy cosmic rays; space-based

Subcategory Future projects

Primary authors

Andres Romero-Wolf (Jet Propulsion Laboratory, California Institute of Technology) Prof. Jaime Alvarez-Muñiz (Universidade Santiago de Compostela, Spain) Prof. Luis A. Anchordoqui (Lehman College, City University of New York) Prof. Douglas Bergman (University of Utah) Dr Washington Rodrigues de Carvalho (Radboud University, The Netherlands) Austin Cummings (Gran Sasso Science Institute) Prof. Peter Gorham (University of Hawaii) Dr Casey Handmer (Jet Propulsion Laboratory, California Institute of Technology) Dr Nate Harvey (Jet Propulsion Laboratory, California Institute of Technology) John Krizmanic (4NASA/Goddard Space Flight Center) Prof. Kurtis Nishimura (University of Hawaii) Dr Eric Oberla (University of Chicago) Mary Hall Reno (University of Iowa) Dr Harm Schoorlemmer (Max Planck Institute für Kernphysik) Prof. Gary Varner (Univeristy of Hawaii) Dr Tonia Venters (NASA Goddard Space Flight Center) Dr Stephanie Wissel (Pennsylvania State University) Prof. Enrique Zas (Universidade Santiago de Compostela, Spain)

Presentation materials