Eur. Phys. J. D (2016) 70: 80
https://doi.org/10.1140/epjd/e2016-60730-8

Regular Article

Formation of H̅ in p̅-Ps collisions embedded in plasmas^*

¹ Institute of Mathematical Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
² Department of Mathematics, Kazi Nazrul University, Nazrul Road, Asansol, 713340 West Bengal, India
³ Department of Mathematics, Burdwan University, Golapbag, 713104 Burdwan, West Bengal, India
⁴ Centre for Foundation Studies in Science, University of Malaya, 50603 Kuala Lumpur, Malaysia

^a e-mail: kuru052001@gmail.com

Received: 28 December 2015
Received in final form: 18 February 2016
Published online: 12 April 2016

Abstract

Screening effects of plasmas on the formation of antihydrogen (H̅) in an arbitrary s-state from the ground state of the positronium atom (Ps) by antiproton (p̅) impact have been studied within the framework of charge-conjugation and time-reversal invariance. Two types of plasma environments have been considered, namely weakly coupled plasma and dense quantum plasma. For weakly coupled plasma, the interactions among the charged particles in plasma have been represented by Debye-Huckel screening model, whereas for dense quantum plasma, interactions among the charged particles in plasma have been represented by exponential cosine-screened Coulomb potentials. Effects of plasma screening on the antihydrogen formation cross section have been studied in the energy range 15–400 keV of incident antiproton. For the free atomic case, our results agree well with some of the most accurate results available in the literature.