First measurement of the antihydrogen production cross section through the charge-exchange reaction of low-energy antiprotons with orthopositronium

GBAR Collaboration; P. Adrich; I. Belosevic; M. Chung; P. Cladé; P. Comini; P. Crivelli; P. Debu; A. Douillet; S. Geffroy; S. Guellati-Khelifa; P. Guichard; P. -A. Hervieux; L. Hilico; P. Indelicato; S. Jonsell; J. -P. Karr; B. Kim; S. Kim; E. -S. Kim; N. Kuroda; B. Lee; L. Liszkay; D. Lunney; G. Manfredi; B. Mansoulié; V. Martimort; M. Matusiak; V. Nesvizhevsky; F. Nez; K. Park; N. Paul; E. Perez; P. Pérez; C. Regenfus; C. Roumegou; J. -Y. Roussé; F. Schmidt-Kaler; K. Szymczyk; T. A. Tanaka; B. Tuchming; D. P. van der Werf; D. Won; S. Wronka; P. Yzombard

arXiv · 2609.33990

First measurement of the antihydrogen production cross section through the charge-exchange reaction of low-energy antiprotons with orthopositronium

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Abstract

The GBAR experiment has measured the formation rate of antihydrogen from antiproton impact on a positronium cloud for antiproton kinetic energies of 4 and 6 keV. This is the first charge-exchange cross section measurement performed using antiproton beams, which are provided by the AD-ELENA facility at CERN. The measured cross section values are $(14.1 \pm 1.3 \mathrm{(stat)} ^{+2.2}_{-1.4} \mathrm{(sys)}) \times 10^{-16}$~cm$^2$ at 6.2 keV energy and $(8.7 \pm 2.4 \mathrm{(stat)} ^{+1.5}_{-0.09} \mathrm{(sys)}) \times 10^{-16}$~cm$^2$ at 4.15 keV energy, and agree with recent theoretical three-body calculations for antihydrogen formation. These measurements are an important input for experiments with antimatter, e.g the planned measurements of antihydrogen gravitational acceleration in the GBAR collaboration.

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GBAR Collaboration, P. Adrich, I. Belosevic, M. Chung, P. Cladé, P. Comini, P. Crivelli, P. Debu, A. Douillet, S. Geffroy, S. Guellati-Khelifa, P. Guichard, P. -A. Hervieux, L. Hilico, P. Indelicato, S. Jonsell, J. -P. Karr, B. Kim, S. Kim, E. -S. Kim, N. Kuroda, B. Lee, L. Liszkay, D. Lunney, G. Manfredi, B. Mansoulié, V. Martimort, M. Matusiak, V. Nesvizhevsky, F. Nez, K. Park, N. Paul, E. Perez, P. Pérez, C. Regenfus, C. Roumegou, J. -Y. Roussé, F. Schmidt-Kaler, K. Szymczyk, T. A. Tanaka, B. Tuchming, D. P. van der Werf, D. Won, S. Wronka, P. Yzombard. 2026-09-27. First measurement of the antihydrogen production cross section through the charge-exchange reaction of low-energy antiprotons with orthopositronium. https://arxiv.org/abs/2609.33990

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