Helium–antihydrogen scattering at low energies

Jonsell, Svante; Armour, E. A. G.; Plummer, Martyn; Liu, Y.; Todd, A.C.

doi:10.1088/1367-2630/14/3/035013

Cited by 8 publications

(9 citation statements)

References 27 publications

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“…Of course, it would be interesting to go further in the analysis by considering explicitly the effect of the short-range part of the interaction potential. This idea has been studied for the case of antihydrogen atom-helium atom interaction, and short-range repulsion predicted [38][39][40][41][42]. It would be worth performing similar calculations for the case of antihydrogen atom-liquid helium interaction studied in the present letter.…”

Section: Discussionmentioning

confidence: 93%

Quantum reflection of antihydrogen from a liquid helium film

Crépin¹,

Kupriyanova²,

Guérout³

et al. 2017

EPL

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We study the quantum reflection of ultracold antihydrogen atoms bouncing on the surface of a liquid helium film. The Casimir-Polder potential and quantum reflection are calculated for different thicknesses of the film supported by different substrates. Antihydrogen can be protected from annihilation for as long as 1.3s on a bulk of liquid 4 He, and 1.7s for liquid 3 He. These large lifetimes open interesting perspectives for spectroscopic measurements of the free fall acceleration of antihydrogen. Variation of the scattering length with the thickness of a film of helium shows interferences which we interpret through a Liouville transformation of the quantum reflection problem.

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Section: Discussionmentioning

confidence: 93%

Quantum reflection of antihydrogen from a liquid helium film

Crépin¹,

Kupriyanova²,

Guérout³

et al. 2017

EPL

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“…However, as energy, and hence angular ) Figure 9. Low-energy cross sections for helium-antihydrogen scattering, calculated using the Born-Oppenheimer approximation [34]: solid line, total inelastic; dash-dot; antiproton capture; short dash, direct alpha particle-antiproton annihilation; dotted, elastic. momentum, increases, the rotational barrier shields the nuclei from each other.…”

Section: (B) Antihydrogen-heliummentioning

confidence: 99%

“…. Low-energy cross sections for helium-antihydrogen scattering, calculated using the Born-Oppenheimer approximation [35]: solid line, total inelastic; dash-dot; antiproton capture; short dash, direct alpha particle-antiproton annihilation; dotted, elastic.…”

Section: Antihydrogen Collisions (A) Antihydrogen-hydrogen Atommentioning

confidence: 99%

“…On the other hand, this makes quantum mechanical approaches based on the Born-Oppenheimer approximation more sound. Such calculations, bases on the very accurate potential calculated by Strasburger et al [34], were performed in [35]. In the zero-energy limit, it turns out that the dominating inelastic process is the direct antiproton-alpha particle annihilation [36], and the second-most important loss process is rearrangement into pHe + and Ps.…”

Section: Antihydrogen Collisions (A) Antihydrogen-hydrogen Atommentioning

confidence: 99%

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Collisions involving antiprotons and antihydrogen: an overview

Jonsell¹

2018

Phil. Trans. R. Soc. A.

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I give an overview of experimental and theoretical results for antiproton and antihydrogen scattering with atoms and molecules (in particular H, He). At low energies ([Formula: see text]1 keV) there are practically no experimental data available. Instead I compare the results from different theoretical calculations, of various degrees of sophistication. At energies up to a few tens of eV, I focus on simple approximations that give reasonably accurate results, as these allow quick estimates of collision rates without embarking on a research project.This article is part of the Theo Murphy meeting issue 'Antiproton physics in the ELENA era'.

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“…In the BO model, the radial wave function has a complex-valued phase shift, and hence the annihilation probability can be evaluated. The BO potential was used for the calculation of the hadronic annihilation in the systems of H +H [9,11] and He +H [46]. In the present case, the BO model is highly satisfactory at very low energies (E coll < 10 −7 eV), but provides about twice as large as the accurate value at high energies where the BO annihilation probability becomes just equal to the 2B probability P 0 p+p because of V 1σ (R) = −1/R − E H at R R FT (see also Ref.…”

Section: The Probability P Jmentioning

confidence: 99%

Unified treatment of hadronic annihilation and protonium formation in slow collisions of antiprotons with hydrogen atoms

Sakimoto

2013

Phys. Rev. A

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Antiproton (p) collisions with hydrogen atoms, resulting in the hadronic process of particle-antiparticle annihilation and the atomic process of protonium (pp) formation (orp capture), are investigated theoretically. As the collision energy decreases, the collision time required for thep capture becomes necessarily longer. Then, there is the possibility that thep-p annihilation occurs significantly before thep capture process completes. In such a case, one can no longer consider the annihilation decay separately from thep capture process. The present study develops a rigorous unified quantum-mechanical treatment of the annihilation andp capture processes. For this purpose, an R-matrix approach for atomic collisions is extended to have complex-valued R-matrix elements allowing for the hadronic annihilation. Detailed calculations are carried out at low collision energies ranging from 10 −8 to 10 −1 eV, and the annihilation and thep capture (total and product-state selected) cross sections are reported. Consideration is given to the difference between the direct annihilation occurring during the collision and the annihilation ofpp occurring after thep capture. The present annihilation process is also compared with the annihilation in two-bodyp + p collisions.

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Helium–antihydrogen scattering at low energies

Cited by 8 publications

References 27 publications

Quantum reflection of antihydrogen from a liquid helium film

Quantum reflection of antihydrogen from a liquid helium film

Collisions involving antiprotons and antihydrogen: an overview

Unified treatment of hadronic annihilation and protonium formation in slow collisions of antiprotons with hydrogen atoms

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