Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

AIP Advances

Simulation of the formation of antihydrogen via magnetobound positronium

F. F. Aguirre, Carlos A. Ordonez

Published Sep 1, 2021• 0 citations
Publisher

Abstract

Antihydrogen formation involving magnetobound positronium is simulated by computing classical trajectories. Simulated collisions between electrons and positrons generate magnetobound positronium, which consists of electron–positron pairs that are not energetically bound but that have spatially correlated trajectories within a magnetic field. Simulations show that antihydrogen can form if such electron–positron pairs pass near antiprotons. In addition, the possibility of forming antihydrogen atomic ions or antihydrogen molecular ions via magnetobound positronium or magnetobound antihydrogen is discussed.

DOI
10.1063/5.0060707

Related papers

Adiabatic formation of quasibound states of antihydrogen

C.E. Correa, J. R. Correa, Carlos A. Ordonez

The classical trajectory of an initially unbound positron within the electric field of an antiproton and a uniform magnetic field is simulated in three dimensions. Several simulations are run incorporating experimental parameters used for antihydrogen production, which has been achieved by two different groups [M. Amoretti, Nature (London) 419, 456 (2002); G. Gabrielse, Phys. Rev. Lett. 89, 213401 (2002)]. The simulations indicate that temporary bound states of antihydrogen can form at positive energies, where the energy of the system is defined to be zero when the positron and antiproton are at rest with infinite separation. Such quasibound states, which form only when the magnetic field is present, are typically smaller than in a dimension perpendicular to the magnetic field. An analytical model is developed for a formation cross section, and it is found that quasibound states may form more frequently than stable Rydberg states.

Physical Review E•Oct 28, 2005•19 citations

Antihydrogen formation by collisions of antiprotons with positronium in a magnetic field

J. Lu, Emil Y. Sidky, Zvjezdana Roller-Lutz +1 more

Using the classical trajectory Monte Carlo method, we calculated the charge-transfer cross section for antiprotons colliding with Rydberg positronium, leading to antihydrogen formation. The results show a significant influence of an externally applied magnetic field which causes a reduction of the cross section.

Physical Review A•Aug 29, 2003•8 citations

Simulations of antihydrogen formation in a nested Penning trap

S. Jonsell, Dirk Peter van der Werf, M. Charlton

We have simulated the formation of antihydrogen through three-body recombination using classical trajectories of antiprotons and positrons. The simulations include several effects which are important in current antihydrogen experiments: the full motion of the antiproton repeatedly passing into and out of the positron plasma, the energy loss of antiprotons due to the interaction with the positron plasma, and the field-ionization of antihydrogen en route from the plasma to the detector. We find that whereas the overall simulated rate of formation of antihydrogen has a density dependence close to n 2 e , the rate of antihydrogen detection follows a power law less than 2. The difference is due to the effect of density dependent field ionization.

Journal of Physics Conference Series•Jan 1, 2010•0 citations

Antihydrogen Formation and Level Population Evolution During Passage Through a Positron Plasma

B. Radics, Daniel J. Murtagh, Y. Yamazaki +1 more

Antihydrogen is at the focus of antimatter research.One of the main aims is to perform a direct test of the fundamental CPT symmetry by comparing the spectroscopic properties of the ground-state antihydrogen atom with those of the hydrogen atom.In current experiments synthetized antihydrogen is formed mainly via the three-body recombination process after mixing positron and antiproton clouds together in a cryogenic trap.The major three-body formation process populates mainly highly excited Rydberg states, therefore before the antihydrogen atoms reach the ground-state additional processes may take place, such as collisional (de)excitation, ionization and spontaneous or stimulated radiative transitions.We have used a classical-trajectory Monte Carlo (CTMC) code along with regular atomic codes to generate a scattering database of rate coefficients in various experimentally achievable magnetic field strengths and in low temperature positron plasma conditions.We used these rates to calculate the evolution of level population of antihydrogen during formation, scattering and flight within our experimental conditions [1].The model and the results are presented.

International Conference on Low Energy Antiproton Physics (LEAP)•Nov 23, 2017•0 citations

Producing ultracold and trappable antihydrogen atoms

S. X. Hu

Both experiments and simulations have shown that the temperature of antihydrogen atoms $(\overline{\mathrm{H}})$ formed in a strongly magnetized positron-antiproton plasma is mainly determined by the heavy particles' temperature. A routine to keep cooling antiprotons $(\overline{p})$ by using ultracold $(<1\phantom{\rule{0.3em}{0ex}}\mathrm{K})$ electrons is proposed under attainable experimental conditions. When cold positrons are loaded into such a low-temperature electron-antiproton mixture, ultracold antihydrogen atoms can be produced at a temperature below $\ensuremath{\sim}1\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. Our large-scale molecular-dynamics simulations, which involve $20\phantom{\rule{0.2em}{0ex}}000$ particles (${e}^{\ensuremath{-}}$, ${e}^{+}$, and $\overline{p}$) evolving up to $1\phantom{\rule{0.3em}{0ex}}\mathrm{\ensuremath{\mu}}\mathrm{s}$, have confirmed the generation of trappable $\overline{\mathrm{H}}$ atoms.

Physical Review A•Jan 29, 2007•4 citations

Near-threshold behavior of positronium-antihydrogen scattering cross sections

Takuma Yamashita, Yasushi Kino, Emiko Hiyama +2 more

The authors numerically study the scattering of antihydrogen and positronium atoms, at collision energies just above the threshold for the rearrangement reaction resulting in antihydrogen positive ions. The formation of such ions is of interest for ongoing or planned experiments involving antimatter with antihydrogen at CERN.

Physical Review A•May 31, 2022•7 citations
Antihydrogen formation involving magnetobound positronium is simulated by computing classical trajectories. Simulated collisions between electrons and positrons generate magnetobound positronium, which consists of electron–positron pairs that are not energetically bound but that have spatially correlated trajectories within a magnetic field. Simulations show that antihydrogen can form if such electron–positron pairs pass near antiprotons. In addition, the possibility of forming antihydrogen atomic ions or antihydrogen molecular ions via magnetobound positronium or magnetobound antihydrogen is discussed.
The classical trajectory of an initially unbound positron within the electric field of an antiproton and a uniform magnetic field is simulated in three dimensions. Several simulations are run incorporating experimental parameters used for antihydrogen production, which has been achieved by two different groups [M. Amoretti, Nature (London) 419, 456 (2002); G. Gabrielse, Phys. Rev. Lett. 89, 213401 (2002)]. The simulations indicate that temporary bound states of antihydrogen can form at positive energies, where the energy of the system is defined to be zero when the positron and antiproton are at rest with infinite separation. Such quasibound states, which form only when the magnetic field is present, are typically smaller than in a dimension perpendicular to the magnetic field. An analytical model is developed for a formation cross section, and it is found that quasibound states may form more frequently than stable Rydberg states.
We have simulated the formation of antihydrogen through three-body recombination using classical trajectories of antiprotons and positrons. The simulations include several effects which are important in current antihydrogen experiments: the full motion of the antiproton repeatedly passing into and out of the positron plasma, the energy loss of antiprotons due to the interaction with the positron plasma, and the field-ionization of antihydrogen en route from the plasma to the detector. We find that whereas the overall simulated rate of formation of antihydrogen has a density dependence close to n 2 e , the rate of antihydrogen detection follows a power law less than 2. The difference is due to the effect of density dependent field ionization.
Antihydrogen is at the focus of antimatter research.One of the main aims is to perform a direct test of the fundamental CPT symmetry by comparing the spectroscopic properties of the ground-state antihydrogen atom with those of the hydrogen atom.In current experiments synthetized antihydrogen is formed mainly via the three-body recombination process after mixing positron and antiproton clouds together in a cryogenic trap.The major three-body formation process populates mainly highly excited Rydberg states, therefore before the antihydrogen atoms reach the ground-state additional processes may take place, such as collisional (de)excitation, ionization and spontaneous or stimulated radiative transitions.We have used a classical-trajectory Monte Carlo (CTMC) code along with regular atomic codes to generate a scattering database of rate coefficients in various experimentally achievable magnetic field strengths and in low temperature positron plasma conditions.We used these rates to calculate the evolution of level population of antihydrogen during formation, scattering and flight within our experimental conditions [1].The model and the results are presented.
Both experiments and simulations have shown that the temperature of antihydrogen atoms (H‾)(\overline{\mathrm{H}})(H) formed in a strongly magnetized positron-antiproton plasma is mainly determined by the heavy particles' temperature. A routine to keep cooling antiprotons (p‾)(\overline{p})(p​) by using ultracold (<1K)(<1\phantom{\rule{0.3em}{0ex}}\mathrm{K})(<1K) electrons is proposed under attainable experimental conditions. When cold positrons are loaded into such a low-temperature electron-antiproton mixture, ultracold antihydrogen atoms can be produced at a temperature below $\ensuremath{\sim}1\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. Our large-scale molecular-dynamics simulations, which involve 2000020\phantom{\rule{0.2em}{0ex}}00020000 particles (${e}^{\ensuremath{-}}$, e+{e}^{+}e+, and p‾\overline{p}p​) evolving up to $1\phantom{\rule{0.3em}{0ex}}\mathrm{\ensuremath{\mu}}\mathrm{s}$, have confirmed the generation of trappable H‾\overline{\mathrm{H}}H atoms.