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Bassalleck, B.; Berdoz, A.; Bradtke, C.; Bröders, R.; Bunker, B.; Dennert, H.; Dutz, H.; Eilerts, S.; Eyrich, W.; Fields, D. E.; Fischer, H.; Franklin, F; Franz, J.; Gehring, R.; Geyer, R.; Goertz, S.; Harmsen, J.; Hauffe, J.; Heinsius, F. H.; Hertzog, D. W.; Johansson, T.; Jones, T. D.; Khaustov, P.; Kilian, K.; Kingsberry, P.; Kriegler, Elmar; Lowe, J.; Meier, A.; Metzger, A. E.; Meyer, C. A.; Meyer, W.; Moosburger, M.; Oelert, W.; Paschke, K.; Plückthun, M.; Pomp, Stephan; Qunn, B; Radtke, Edgar; Reicherz, G.; Röhrich, K.; Sachs, K.; Schmitt, H.; Schoch, B.; Sefzick, T.; Stinzing, F.; Stotzer, R.; Tayloe, R.; Wirth, S.

doi:10.1103/physrevlett.89.212302

Cited by 15 publications

(6 citation statements)

References 24 publications

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“…In spite of a warning that longitudinal polarization might give larger effect, a transverse polarization was considered as an obvious choice, as it gives access to more observables. A detailed analysis of the latest PS185 are published in [91,92].…”

Section: Hyperon-pair Productionmentioning

confidence: 99%

Antiproton Physics

Richard

2020

Front. Phys.

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We review the physics of low-energy antiprotons, and its link with the nuclear forces. This includes: antinucleon scattering on nucleons and nuclei, antiprotonic atoms and antinucleon-nucleon annihilation into mesons. Modern perspectives 39 Outlook 39 1 A brief historyIn 1932, the positron, the antiparticle of the electron, was discovered in cosmic rays and confirmed in the β + decay of some radioactive nuclei. See, e.g., the Nobel lecture by Anderson [1]. It was then reasonably anticipated that the proton also has an antiparticle, where A denotes the target nucleus. For A = p, this is a standard exercise in relativistic kinematics to demonstrate that the kinetic energy of the incoming proton should be higher than 6 m, where m is the proton mass, and c = 1. This threshold decreases if the target is more massive. The Bevatron was completed in 1954, and the antiproton was discovered in 1955 by a team lead by Chamberlain and Segrè, who were awarded the Nobel prize in 1959. 2 Shortly after the antiproton, the antineutron,n, was also discovered at Berkeley, and up to now, for any new elementary particle, the corresponding antiparticle has also been found. The discovery of the first anti-atom was well advertised [2], but this was not the case for the earlier observation of the first antinucleus, antideuterium, because of a controversy between an European team [3] and its US competitors [4]. In experiments at very high energy, in particular collisions of heavy ions at STAR (Brookhaven) and ALICE (CERN), one routinely produces light antinuclei and even anti-hypernuclei (in which an antinucleon is replaced by an antihyperonΛ) [5][6][7].The matter-antimatter symmetry is almost perfect, except for a slight violation in the sector of weak interactions, which is nearly exactly compensated by a simultaneous violation of the left-right symmetry, i.e., the product P C of parity P and charge-conjugation C is only very marginally violated. Up to now, there is no indication of any violation of the product CP T , where T is the time-reversal operator: this implies that the proton and antiproton have the same mass, a property now checked to less than 10 −9 [8].Many experiments have been carried out with low energy antiprotons, in particular at Brookhaven and CERN in the 60s and 70s, with interesting results, in particular for the physics of the mesons produced by annihilation. However, in these early experiments, the antiprotons were part of secondary beams containing many negativelycharged pions and kaons, and with a wide momentum spread.In the 70s, Simon van der Meer, and his colleagues at CERN and elsewhere imagined and developed the method of stochastic cooling [9], which produces antiproton beams of high purity, sharp momentum resolution, and much higher intensity than in the previous devices. CERN transformed the fixed-target accelerator SpS into a protonantiproton collider, SppS, with the striking achievement of the discovery of the W ± and Z 0 , the intermediate bosons of the electro-weak interaction. A similar scheme was lat...

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Section: Hyperon-pair Productionmentioning

confidence: 99%

Antiproton Physics

Richard

2020

Front. Phys.

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“…However, there are also some serious problems for the polarized-strangeness model. For example, the strong OZI 'violation' inpp → γφ takes place from a 1 S 0 initial state, and the spin transfer D nn in pp → ΛΛ is small, whereas K nn > 0, indicating that the spin of the proton is transferred to theΛ, not to the Λ [39]. Moreover, CLAS data on the reaction ep → e ′ K + Λ indicate that the spins of the s ands are anti-aligned [40].…”

Section: Ozi Violation or Evasion?mentioning

confidence: 99%

Today’s view on strangeness

Ellis

2005

Eur. Phys. J. A

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There are several different experimental indications, such as the pion-nucleon Σ term and polarized deep-inelastic scattering, which suggest that the nucleon wave function contains a hidden ss component. This is expected in chiral soliton models, which also predicted the existence of new exotic baryons that may recently have been observed. Another hint of hidden strangeness in the nucleon is provided by copious φ production in various NN annihilation channels, which may be due to evasions of the Okubo-Zweig-Iizuka rule. One way to probe the possible polarization of hidden ss pairs in the nucleon may be via Λ polarization in deep-inelastic scattering.

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“…Entangled pairs can be produced for example via proton-antiproton annihilation and the full spin structure can be experimentally determined 13 . In this section we analyse the entanglement properties and discuss whether Bell’s nonlocality or contextuality can be revealed in such experiments.…”

Section: Resultsmentioning

confidence: 99%

“…Our formalism extends straightforwardly to the two-particle case by taking the tensor product of the Kraus operators. Experiments 13 14 15 suggest that the initial spin state is a maximally entangled Bell state (except for backward scattering angles). Therefore without loss of generality we can choose the antisymmetric Bell state and the angular momentum distribution becomes …”

Section: Resultsmentioning

confidence: 99%

Limits Of Quantum Information In Weak Interaction Processes Of Hyperons

Hiesmayr

2015

Sci Rep

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We analyze the achievable limits of the quantum information processing of the weak interaction revealed by hyperons with spin. We find that the weak decay process corresponds to an interferometric device with a fixed visibility and fixed phase difference for each hyperon. Nature chooses rather low visibilities expressing a preference to parity conserving or violating processes (except for the decay Σ+→ pπ0). The decay process can be considered as an open quantum channel that carries the information of the hyperon spin to the angular distribution of the momentum of the daughter particles. We find a simple geometrical information theoretic interpretation of this process: two quantization axes are chosen spontaneously with probabilities where α is proportional to the visibility times the real part of the phase shift. Differently stated, the weak interaction process corresponds to spin measurements with an imperfect Stern-Gerlach apparatus. Equipped with this information theoretic insight we show how entanglement can be measured in these systems and why Bell’s nonlocality (in contradiction to common misconception in literature) cannot be revealed in hyperon decays. Last but not least we study under which circumstances contextuality can be revealed.

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Measurement of Spin-Transfer Observables inp¯p→Λ¯Λat1.637 G

Cited by 15 publications

References 24 publications

Antiproton Physics

Antiproton Physics

Today’s view on strangeness

Limits Of Quantum Information In Weak Interaction Processes Of Hyperons

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