| 1. |
- Anselmino, M., et al.
(författare)
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Predictions for single spin asymmetries in ℓ parrow -> π X and γ * parrow -> π X
- 2000
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 13:3, s. 519-526
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Tidskriftsartikel (refereegranskat)abstract
- Predictions for the single transverse spin asymmetry AN in semi-inclusive DIS processes are given; non-negligible values of AN may arise from spin effects in the fragmentation of a polarized quark into a final hadron with a transverse momentum ěc k⊥ with respect to the jet axis, the so-called Collins effect. The elementary single spin asymmetry of the fragmenting quark has been fixed in a previous paper, by fitting data on parrow p -> π X, and by assuming that the QCD factorization theorem holds also when transverse momenta are taken into account. The predictions given here are based on the assumption that the Collins effect is the only cause of the observed single spin asymmetries in parrow p -> π X. Eventual spin and ěc k⊥ dependences in the quark distribution functions, the so-called Sivers effect, are also discussed.
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| 2. |
- Sandin, Fredrik
(författare)
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Compact stars in the standard model - and beyond
- 2005
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 40:Supplement 2, s. 15-22
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Tidskriftsartikel (refereegranskat)abstract
- In the context of the standard model of particle physics, there is a definite upper limit to the density of stable compact stars. However, if there is a deeper layer of constituents, below that of quarks and leptons, stability may be re-established far beyond this limiting density and a new class of compact stars could exist. These objects would cause gravitational lensing of gamma-ray bursts and white dwarfs, which might be observable as line features in the spectrum. Such observations could provide means for obtaining new clues about the fundamental particles and the nature of cold dark matter.
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