The review of antihydrogen-positronium interactions (the reference list)

The Antiworld Review №4, 2018

author: Daniel L. Miller

  1. Formation of positron-atom bound states in collisions between Rydberg Ps and neutral atoms, A. R. Swann, D. B. Cassidy, A. Deller, and G. F. Gribakin, Phys. Rev. A 93, 052712;
  2. J. W. Humberston, M. Charlton, F. M. Jacobsen, and B. I. Deutch. On antihydrogen formation in collisions of antiprotons with positronium. J. Phys. B: At. Mol. Phys., 20:L25–L29, 1987. (One of 1st papers put forward an idea of 4-body interaction for making antihydrogen)
  3. Paper of B. I. Deutch (1986) explains antiproton (or proton) capture by neutral beams (eg positronium). The adiabatic crossection is \sigma_A = \pi a^2 [1+1/E (e^2/a – 1/2 Ry)], where a is the Bohr radius of the proton, \pi a^2 = 0.88E-16cm^-2. It is 5 orders above the radiative crossection \sigma = \pi^2 a^2 \alpha^3 Ry/E Ln(1+4Ry/E);
  4. Study of the antihydrogen atom and ion formation in the collisions antiproton-positronium, Pauline Comini, 2015 (4-body interaction for producing antihydrogen ion and electron from collision of antihydrogen neutral atom and positronium)
  5. Continuum Distorted Wave method for charge transfer in ion-atom collisions (I’ll follow up)
  6. J. C. Straton and R. J. Drachman. Formation of positronium in e+ + H− collisions. Phys. Rev. A, 44:7335, 1991. (This is the conjugated channel to Comini’s proposal)
  7. I still don’t understand why antihydrogen ions have not been observed so far; once antihydrogen nuclear is passing through positronium trap it can pickup as many positrons as the crossection allows.
  8. Antihydrogen ion (One can call it antihydrogen anyon in analogy to hydrogen anyon) is expected to have the total ground state energy −14.359888 eV, slightly below Rydberg of −13.605eV; removing 1st electron cost 0.7eV; besides it does not have excited states. The binding energy of positronium is −6.8 eV (1/2 Rydberg). So energy must be spent to transfer positron from positronium to anihydrogen. However crossections (at least for main channels when both antihydrogen and positronium are in 1S states) are not small, comparable to above adiabatic crossection of transfer positron from positronium to antiproton.
  9. One more issue is related to spins of positrons in the positronium and in the antihydrogen before collision. They must be opposite, because this is the only allowed configuration in antyhydrogen anyon. In the same time the experimental setups for positronium and for antihydrogen storage have magnetic fields and positron spins before collision can be accidentally aligned.
  10. Nobuhiro Yamanaka and Yasushi Kino, Phys. Rev. A 65, 062709 (2002)
  11. S. Roy, S. Ghosh Deb, and C. Sinha, Phys. Rev. A 78, 022706 (2008)
  12. A. S. Kadyrov, I. Bray, M. Charlton & I. I. Fabrikant, Nature Communications, volume 8, Article number: 1544 (2017)
  13. R Lazauskas, P-A Hervieux, M Dufour and M Valdes, Journal of Physics B: Atomic, Molecular and Optical Physics, Volume 49, Number 9 (2016)
  14. Few papers above discuss the crossection of positron (electron) capture by antiproton (proton) from positronium vs positronium state. IMHO the crossection should drop fast with main quantum number of positronium because capture of free positron/electron if 5 orders lower than capture of bounded positron/electron by simple arguments of Deutch.
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