Special issue on antihydrogen and positronium

Charlton, M.; Mills, A. P.; Yamazaki, Y.

doi:10.1088/1361-6455/aa75d8

Cited by 10 publications

(7 citation statements)

References 76 publications

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“…Exactly the same conclusion as in the present study can be derived also for the charge-conjugation system pH. In recent experimental studies ofH production [14][15][16], theH atoms are cold and are found to be in high Rydberg states [60]. This suggests that the p +H(n 2) system rather thanp + H may be more favorable for realizing the creation of stable exotic molecules.…”

Section: Summary and Further Discussionsupporting

confidence: 86%

“…Recently, there has been a great deal of progress in experiments producing antihydrogenH = e +p at very low temperatures (∼10 K) [14][15][16]. A lively concern is entertained for theH + H system: it has an attractive dispersion interaction asymptotically, and the BO approximation is appropriate at least for intermediate and large separations [17][18][19][20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

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Exotic molecules consisting of an antiproton and a hydrogen atom

Sakimoto

2018

Phys. Rev. A

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A theoretical study is conducted on the stability of exotic antiproton-hydrogen molecular anions (pH), which in the separated atom limit correlate withp + H(n = 2) (n being the principal quantum number). Thē pH molecule in the electronic ground state is highly unstable due to pair annihilation and autodetachment (→pp + e). However, if thepH molecule is electronically excited, the molecular stability can be drastically improved. Since the excited states of the H atom have accidental degeneracy, the asymptotic form of the Born-Oppenheimer potential curve ofp + H(n = 2) behaves as 1/R 2 (R being the relative distance), which can play a critical role in the bonding and stability of the molecule. It is found that thepH molecule in the first electronic excited state and in a high rotational state is sufficiently stable and has a lifetime dominated by spontaneous radiative emission (→p + H + hν). ThepH system is dynamically similar to H 2 − , which had been commonly considered to be unstable due to autodetachment. However, recent measurements of ion-beam sputtering unambiguously verified the existence of long-lived H 2 − molecules in high rotational states. This suggests that thepH molecules may actually be created if one employs experimental means such as the chemical sputtering of hydrogen-rich targets withp beams.

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Section: Summary and Further Discussionsupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Exotic molecules consisting of an antiproton and a hydrogen atom

Sakimoto

2018

Phys. Rev. A

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“…The Monte-Carlo simulation of initial velocities is obtained by sampling random variables corresponding to the different sources of uncertainty. The distribution in the trap is generated using a normal distribution function with a dispersion (1). Such distribution is directly computed using available random generator.…”

Section: Distribution Of Annihilation Eventsmentioning

confidence: 99%

“…The asymmetry between matter and antimatter observed in the Universe is one of the fundamental problems of modern physics challenging the Standard Model [1]. Hints on this puzzle are looked for in experiments testing CPT symmetry between matter and antimatter as well as the interaction of antimatter with gravity [2,3,4].…”

Section: Introductionmentioning

confidence: 99%

Analysis of the timing of freely falling antihydrogen

Rousselle,

Cladé,

Guellati-Khélifa

et al. 2021

Preprint

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We evaluate the accuracy to be expected for the measurement of free fall acceleration of antihydrogen in the GBAR experiment, accounting for the recoil transferred in the photodetachment process. We show that the uncertainty on the measurement of gravity comes mainly from the initial velocity dispersion in the ion trap so that the photodetachment recoil is not the limiting factor to the precision as a naive analysis would suggest. This result will ease the constraints on the choice of the photodetachment laser parameters.

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“…One of the fascinating questions which remain open in modern physics is the asymmetry between matter and antimatter observed in the Universe but not fully accounted for in the Standard Model [1][2][3][4]. In particular experimental tests of the effect of gravity on antimatter must still be improved [5].…”

Section: Introductionmentioning

confidence: 99%

Improving the statistical analysis of anti-hydrogen free fall by using near edge events

Rousselle,

Cladé,

Guellati-Khélifa

et al. 2021

Preprint

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An accurate evaluation of the gravity acceleration from the timing of free fall of anti-hydrogen atoms in the GBAR experiment requires to account for obstacles surrounding the anti-matter source. These obstacles reduce the number of useful events but may improve accuracy since the edges of the shadow of obstacles on the detection chamber depends on gravity, bringing additional information on the value of g. We perform Monte Carlo simulations to obtain the dispersion and give a qualitative understanding of the results by analysing the statistics of events close to an edge. We also study the effect of specular quantum reflections of anti-hydrogen on surfaces and show that they do not degrade the accuracy that much.

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Special issue on antihydrogen and positronium

Cited by 10 publications

References 76 publications

Exotic molecules consisting of an antiproton and a hydrogen atom

Exotic molecules consisting of an antiproton and a hydrogen atom

Analysis of the timing of freely falling antihydrogen

Improving the statistical analysis of anti-hydrogen free fall by using near edge events

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