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Polarization and en...
Polarization and entanglement in baryon-antibaryon pair production in electron-positron annihilation
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Ablikim, M. (author)
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- Ikegami Andersson, Walter (author)
- Uppsala universitet,Kärnfysik
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- Johansson, Tord (author)
- Uppsala universitet,Kärnfysik
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- Kupsc, Andrzej (author)
- Uppsala universitet,Kärnfysik
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- Li, Cui, 1984- (author)
- Uppsala universitet,Kärnfysik
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- Papenbrock, Michael (author)
- Uppsala universitet,Kärnfysik
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- Pettersson, Joachim (author)
- Uppsala universitet,Kärnfysik
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- Schönning, Karin, 1978- (author)
- Uppsala universitet,Kärnfysik
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- Wolke, Magnus (author)
- Uppsala universitet,Kärnfysik
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Zou, J. H. (author)
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(creator_code:org_t)
- 2019-05-06
- 2019
- English.
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In: Nature Physics. - : Nature Publishing Group. - 1745-2473 .- 1745-2481. ; 15:7, s. 631-634
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http://arxiv.org/pdf...
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https://urn.kb.se/re...
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Abstract
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- Particles directly produced at electron-positron colliders, such as the J/psi meson, decay with relatively high probability into a baryon-antibaryon pair(1). For spin-1/2 baryons, the pair can have the same or opposite helicites. A non-vanishing phase Delta Phi between the transition amplitudes to these helicity states results in a transverse polarization of the baryons(2-4). From the joint angular distribution of the decay products of the bary-ons, this phase as well as the parameters characterizing the baryon and the antibaryon decays can be determined. Here, we report the measurement of Delta Phi = 42.4 +/- 0.6 +/- 0.5 degrees using Lambda -> p pi(-) and (Lambda) over bar -> (p) over bar pi(+), (n ) over bar pi(0) decays at BESIII. We find a value for the Lambda -> p pi(-) decay parameter of alpha(-) = 0.750 +/- 0.009 +/- 0.004, 17 +/- 3% higher than the current world average, which has been used as input for all Lambda polarization measurements since 1978(5,6). For (Lambda) over bar -> (p) over bar pi(+) we find alpha(+) = -0.758 +/- 0.010 +/- 0.007, giving A(CP) = (alpha(-) + alpha(+))/(alpha(-) - alpha(+)) = -0.006 +/- 0.012 +/- 0.007, a precise direct test of charge-parity symmetry (CP) violation in Lambda decays.
Subject headings
- NATURVETENSKAP -- Fysik -- Subatomär fysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Subatomic Physics (hsv//eng)
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- ref (subject category)
- art (subject category)
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Ablikim, M.
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Ikegami Andersso ...
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Johansson, Tord
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Kupsc, Andrzej
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Li, Cui, 1984-
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Papenbrock, Mich ...
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show more...
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Pettersson, Joac ...
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Schönning, Karin ...
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Wolke, Magnus
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Zou, J. H.
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show less...
- About the subject
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- NATURAL SCIENCES
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NATURAL SCIENCES
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and Physical Science ...
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and Subatomic Physic ...
- Articles in the publication
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Nature Physics
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Uppsala University