There are two known methods to generate protonium. One method involves violent particle collisions. The other method involves putting antiprotons and protons into the same magnetic cage. The latter method was first used during the experiment ATHENA (ApparaTus for High precision Experiment on Neutral Antimatter) at the CERN laboratory in Geneva in 2002, but it was not until 2006 that scientists realized protonium was also generated during the experiment.[3]
Reactions involving a proton and an antiproton at high energies give rise to many-particle final states. In fact, such reactions are the basis of particle colliders such as the Tevatron at Fermilab. Indirect searches for protonium at LEAR (Low Energy Antiproton Ring at CERN) have used antiprotons impinging on nuclei such as helium, with unclear results. Very low energy collisions in the range of 10 eV to 1 keV may lead to the formation of protonium.
Studiesedit
Planned experiments will use traps as the source of low energy antiprotons. Such a beam would be allowed to impinge on atomic hydrogen targets, in the field of a laser, which is meant to excite the bound proton–antiproton pairs into an excited state of protonium with some efficiency (whose computation is an open theoretical problem). Unbound particles are rejected by bending them in a magnetic field. Since the protonium is uncharged, it will not be deflected by such a field. This undeflected protonium, if formed, would be allowed to traverse a meter of high vacuum, within which it is expected to decay via annihilation of the proton and antiproton. The decay products would give unmistakable signatures of the formation of protonium.
Theoretical studies of protonium have mainly used non-relativistic quantum mechanics. These give predictions for the binding energy and lifetime of the states. Computed lifetimes are in the range of 0.1 to 10 microseconds. Unlike the hydrogen atom, in which the dominant interactions are due to the Coulomb attraction of the electron and the proton, the constituents of protonium interact predominantly through the strong interaction. Thus multiparticle interactions involving mesons in intermediate states may be important. Hence the production and study of protonium would be of interest also for the understanding of internucleon forces.
Zurlo, N.; et al. (2006). "Evidence For The Production Of Slow Antiprotonic Hydrogen In Vacuum". Physical Review Letters. 97 (15): 153401. arXiv:0708.3717. Bibcode:2006PhRvL..97o3401Z. doi:10.1103/PhysRevLett.97.153401. PMID 17155325. S2CID 36091971.
April 11, 2024
protonium, symbol, citation, needed, also, known, antiprotonic, hydrogen, type, exotic, atom, which, proton, symbol, antiproton, symbol, orbit, each, other, since, protonium, bound, system, particle, corresponding, antiparticle, example, type, exotic, atom, ca. Protonium symbol Pn citation needed also known as antiprotonic hydrogen is a type of exotic atom in which a proton symbol p and an antiproton symbol p orbit each other 1 Since protonium is a bound system of a particle and its corresponding antiparticle it is an example of a type of exotic atom called an onium An illustration of the protonium atom For the isotope 1H and the corresponding hydrated ion see Protium and Hydronium Protonium has a mean lifetime of approximately 1 0 ms and a binding energy of 0 75 keV 2 Like all onia protonium is a boson with all quantum numbers baryon number flavour quantum numbers etc and electrical charge equal to 0 Contents 1 Production 2 Studies 3 See also 4 References 5 Further readingProduction editThere are two known methods to generate protonium One method involves violent particle collisions The other method involves putting antiprotons and protons into the same magnetic cage The latter method was first used during the experiment ATHENA ApparaTus for High precision Experiment on Neutral Antimatter at the CERN laboratory in Geneva in 2002 but it was not until 2006 that scientists realized protonium was also generated during the experiment 3 Reactions involving a proton and an antiproton at high energies give rise to many particle final states In fact such reactions are the basis of particle colliders such as the Tevatron at Fermilab Indirect searches for protonium at LEAR Low Energy Antiproton Ring at CERN have used antiprotons impinging on nuclei such as helium with unclear results Very low energy collisions in the range of 10 eV to 1 keV may lead to the formation of protonium Studies editPlanned experiments will use traps as the source of low energy antiprotons Such a beam would be allowed to impinge on atomic hydrogen targets in the field of a laser which is meant to excite the bound proton antiproton pairs into an excited state of protonium with some efficiency whose computation is an open theoretical problem Unbound particles are rejected by bending them in a magnetic field Since the protonium is uncharged it will not be deflected by such a field This undeflected protonium if formed would be allowed to traverse a meter of high vacuum within which it is expected to decay via annihilation of the proton and antiproton The decay products would give unmistakable signatures of the formation of protonium Theoretical studies of protonium have mainly used non relativistic quantum mechanics These give predictions for the binding energy and lifetime of the states Computed lifetimes are in the range of 0 1 to 10 microseconds Unlike the hydrogen atom in which the dominant interactions are due to the Coulomb attraction of the electron and the proton the constituents of protonium interact predominantly through the strong interaction Thus multiparticle interactions involving mesons in intermediate states may be important Hence the production and study of protonium would be of interest also for the understanding of internucleon forces See also editPositronium Antiprotonic helium Antiproton Collector Antiproton AccumulatorReferences edit Zurlo N et al 2006 Production Of Slow Protonium In Vacuum Hyperfine Interactions 172 1 3 97 105 arXiv 0801 3193 Bibcode 2006HyInt 172 97Z doi 10 1007 s10751 007 9529 0 S2CID 119182686 Abdel Raouf Mohamed Assad 2009 Binding energy of protonium ions Journal of Physics Conference Series 194 7 072003 Bibcode 2009JPhCS 194g2003A doi 10 1088 1742 6596 194 7 072003 L Venturelli et al Athena collaboration August 2007 Protonium production in ATHENA PDF Nuclear Instruments and Methods in Physics Research Section B 261 1 2 40 43 Bibcode 2007NIMPB 261 40V doi 10 1016 j nimb 2007 04 135 Further reading editBattersby S 13 October 2006 Antimatter and matter combine in chemical reaction New Scientist Retrieved 2015 06 26 Klempt E Bradamante F Martin A Richard J M 2002 Antinucleon nucleon interaction at low energy scattering and protonium PDF Physics Reports 368 2 3 119 316 Bibcode 2002PhR 368 119K doi 10 1016 S0370 1573 02 00144 8 Zurlo N et al 2006 Evidence For The Production Of Slow Antiprotonic Hydrogen In Vacuum Physical Review Letters 97 15 153401 arXiv 0708 3717 Bibcode 2006PhRvL 97o3401Z doi 10 1103 PhysRevLett 97 153401 PMID 17155325 S2CID 36091971 Retrieved from https en wikipedia org w index php title Protonium amp oldid 1212596674, wikipedia, wiki, book, books, library,
