Table 1 Figures of merit characterising antihydrogen formation and trapping efficiencies

From: Antihydrogen accumulation for fundamental symmetry tests

\(\overline {\bf {p}} \) injected (×104)

\(\overline {\bf{H}} \) formed (×104)

\({{\bf {T}}_{{{\bf{e}}^ + }}}\)before (K)

\({{\bf {T}}_{{{\bf{e}}^ + }}}\)after (K)

Number of trials

\(\overline {\bf{H}} \) trapped & detected

\(\overline {\bf{H}} \) trapping efficiency (× 10−4)

AR injection mixing a

1.31 ± 0.01

0.53 ± 0.01

27 ± 3

51 ± 1

54

0.62 ± 0.11

1.6 ± 0.3

3.1 ± 0.1

0.87 ± 0.01

27 ± 3

60 ± 1

27

0.59 ± 0.15

0.9 ± 0.2

Potential merge mixing b

5.5 ± 0.1

2.4 ± 0.1

18 ± 2

16 ± 1

16

8.7 ± 0.7

4.7 ± 0.4

9.0 ± 0.3

3.1 ± 0.1

18 ± 2

17 ± 1

26

10.5 ± 0.6

4.7 ± 0.3

  1. Antiprotons were evaporatively cooled to ~40 K in all cases. aAR injection mixing. The positron plasma comprised 2.3 × 106 positrons at a density of 1.3 × 108 cm−3 and a radius of 0.55 mm. b1 s potential merge mixing. The positron plasma comprised 1.6 × 106 positrons at a density of 6.5 × 107 cm−3 and a radius of 0.66 mm. The trapping efficiency is the number of trapped antihydrogen divided by the number formed (annihilation detector efficiencies included). The positron densities were set by tuning the evaporative cooling process to achieve maximum trapping efficiency. Uncertainties are statistical and assume the parent distributions are Poissonian