Collisional and Spectroscopic Studies of Exotic Atoms Using Ultra-Slow Antiprotons

Journal Article · Fri Jul 10 00:00:00 EDT 2009 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.3192301· OSTI ID:21344285

Torii, H A; Toyoda, H; Kuroda, N ^[1]; Nagata, Y; Yamazaki, Y ^[1]; Imao, H ^[2]; Varentsov, V L ^[3]

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1. Institute of Physics, University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902 (Japan)
2. Atomic Lab., RIKEN, 2-1 Hirosawa, Saitama 351-0198 (Japan)
3. Institute for Theoretical and Experimental Physics, Moscow 117218 (Russian Federation)

Antiproton, the antiparticle of proton, is a unique projectile in the study of atomic collision physics, which can be treated theoretically either as a 'negative proton' or a 'heavy electron'. Atomic capture of an antiproton will result in formation of a highly excited exotic atom. Antiprotonic helium atom has been studied intensively by means of precision laser spectroscopy, which has led to a stringent determination of antiproton mass and charge to a level of ppb. Comparison of these values with those of proton gives one of the best tests of CPT invariance, the most fundamental symmetry in physics. However, the dynamic processes of antiproton capture remain unclarified, except for some indirect information given by those optical and X-ray observations. With an aim to produce an antiproton beam at atomic-physics energies for 'pure' collision experiments, we have so far developed techniques to decelerate, cool and confine antiprotons in vacuo, using a sequential combination of the Antiproton Decelerator (AD) at CERN, a Radio-Frequency Quadrupole Decelerator (RFQD), and an electromagnetic trap. Our recent success in stable extraction of monoenergetic ultra-slow antiprotons, about 3x10{sup 5} in number available every 5 minutes, has opened up the possibility to study ionization and atomic capture processes between an antiproton thus provided as a beam and an atom prepared in the form of a supersonic gas-jet target, at an unprecedented low energy from 10 eV to 1 keV under the single-collision condition. Our design and strategy of the cross-beam experiments are discussed.

• OSTI ID: 21344285
• Journal Information: AIP Conference Proceedings, Vol. 1150, Issue 1; Conference: 3. international meeting on frontiers in physics, Kuala Lumpur (Malaysia), 12-16 Jan 2009; Other Information: DOI: 10.1063/1.3192301; (c) 2009 American Institute of Physics; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ANTIPROTON BEAMS
ANTIPROTONS
ATOM COLLISIONS
CAPTURE
CERN
COMPARATIVE EVALUATIONS
CPT THEOREM
ELECTRIC CHARGES
ELECTRONS
EV RANGE
EXCITED STATES
HADRONIC ATOMS
HELIUM
IONIZATION
KEV RANGE
LASER SPECTROSCOPY
REST MASS
SYMMETRY
TRAPS
ANTIBARYONS
ANTIMATTER
ANTINUCLEI
ANTINUCLEON BEAMS
ANTINUCLEONS
ANTIPARTICLE BEAMS
ANTIPARTICLES
ATOMS
BARYONS
BEAMS
COLLISIONS
ELEMENTARY PARTICLES
ELEMENTS
ENERGY LEVELS
ENERGY RANGE
EVALUATION
FERMIONS
FLUIDS
GASES
HADRONS
INTERNATIONAL ORGANIZATIONS
INVARIANCE PRINCIPLES
LEPTONS
MASS
MATTER
NONMETALS
NUCLEI
NUCLEONS
PROTONS
RARE GASES
SPECTROSCOPY