| 1. |
- Akhmedov, Evgeny, et al.
(författare)
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T violation in neutrino oscillations in matter
- 2001
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Ingår i: Nuclear Physics B. - : Elsevier Science B.V.. - 0550-3213 .- 1873-1562. ; 608:02-jan, s. 394-422
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Tidskriftsartikel (refereegranskat)abstract
- We consider the interplay of fundamental and matter-induced T violation effects in neutrino oscillations in matter. After discussing the general features of these effects we derive a simple approximate analytic expression for the T-violating probability asymmetry DeltaP(ab)(T) for three-flavour neutrino oscillations in a matter with an arbitrary density profile in terms of the two-flavour neutrino amplitudes. Explicit examples are given for the cases of a two-layer medium and for the adiabatic Emit in the general case. We then discuss implications of the obtained results for long baseline experiments. We show, in particular, that asymmetric matter effects cannot hinder the determination of the fundamental CP- and T-violating phase delta (CP) in the long baseline experiments as far as the error in this determination is larger than 1% at 99% CL. Since there are no T-violating effects in the two-flavour case, and in the limits of vanishing theta (13) or Deltam(21)(2) the three-flavour neutrino oscillations effectively reduce to the two-flavour ones, studying the T-violating asymmetries ApT ab can in principle provide us with a complementary means of measuring theta (13) and Deltam(21)(2).
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| 2. |
- Amoros, G., et al.
(författare)
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QCD isospin breaking in meson masses, decay constants and quark mass ratios
- 2001
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Ingår i: Nuclear Physics B. - 0550-3213. ; 602:1-2, s. 87-108
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Tidskriftsartikel (refereegranskat)abstract
- The procedure to calculate masses and matrix-elements in the presence of mixing of the basis states is explained in detail. We then apply this procedure to the two-loop calculation in Chiral Perturbation Theory of pseudoscalar masses and decay constants including quark mass isospin breaking. These results are used to update our analysis of Kℓ4 done previously and obtain a value of mu/md in addition to values for the low-energy-constants Li r.
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| 3. |
- Andersson, Bo, et al.
(författare)
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The lambda-measure and the generalised dipoles in the Lund model
- 2002
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Ingår i: Nuclear Physics, Section B. - 0550-3213. ; 646:1-2, s. 102-126
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate that the multiple gluon emission phase space in the dipole cascade model has a strong linear correlation with the number of gluons emitted. The number of gluons per unit available phase space at a certain resolution scale is found to be remarkably independent of the cms energy and global event properties like thrust, and even changes in the ordering variable or resolution scale. We show that the distribution of sizes of gluon-gluon dipoles in a parton cascade has stability properties which are sufficient to account for those of the phase space variable. We observe that certain more abstract entities, defined in the context of hadronisation and related to the gluon emission phase space, share those properties of colour dipoles and name them generalised dipoles. We also present an analytical model to qualitatively describe our findings. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 4. |
- Bijnens, Johan, et al.
(författare)
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Comment on the pion pole part of the light-by-light contribution to the muon g-2
- 2002
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Ingår i: Nuclear Physics, Section B. - 0550-3213. ; 626:1-2, s. 410-411
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Tidskriftsartikel (refereegranskat)abstract
- We comment on the recent calculations of the pion pole part of the light-by-light contribution to the muon anomalous magnetic moment and we point out where the analysis in our previous work was mistaken.
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| 5. |
- Bijnens, Johan, et al.
(författare)
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K -> 3 pi decays in chiral perturbation theory
- 2003
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Ingår i: Nuclear Physics, Section B. - 0550-3213. ; 648:1-2, s. 317-344
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Tidskriftsartikel (refereegranskat)abstract
- The CP conserving amplitudes for the decays K --> 3pi are calculated in chiral perturbation theory at the next-to-leading order. We present the expressions in a compact form with single parameter functions only. These expressions are then fitted to all available K --> 2pi and K --> 3pi data to obtain a fit of the parameters that occur. We compare with the work of Kambor, Missimer and Wyler. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 6. |
- Bijnens, Johan, et al.
(författare)
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K-l3 decays in chiral perturbation theory
- 2003
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Ingår i: Nuclear Physics, Section B. - 0550-3213. ; 669:1-2, s. 341-362
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Tidskriftsartikel (refereegranskat)abstract
- The process K-l3 is calculated to two-loop order (p(6)) in chiral perturbation theory (ChPT) in the isospin conserved case. We present expressions suitable for use with previous work in two-loop ChPT where the order p(4) parameters (L-i(r)) were determined from experiment. We point out that all the order p(6) parameters (C-i(r)) that appear in the value of f(+)(0) relevant for the determination of V-us can be determined from K-l3 measurements via the slope and the curvature of the scalar form-factor. As by product we update the value of the CKM matrix element V-us. (C) 2003 Elsevier B.V. All rights reserved.
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| 7. |
- Fjelstad, Jens, 1971-, et al.
(författare)
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CFT description of three-dimensional Kerr-de Sitter space-time
- 2002
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Ingår i: Nuclear Physics B. - : Elsevier. - 0550-3213 .- 1873-1562. ; 641:1-2, s. 376-392
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Tidskriftsartikel (refereegranskat)abstract
- We describe three-dimensional Kerr-de Sitter space using similar methods as recently applied to the BTZ black hole. A rigorous form of the classical connection between gravity in three dimensions and two-dimensional conformal field theory is employed, where the fundamental degrees of freedom are described in terms of two dependent SL(2,C) currents. In contrast to the BTZ case, however, quantization does not give the Bekenstein-Hawking entropy connected to the cosmological horizon of Kerr-de Sitter space.
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| 8. |
- Fjelstad, Jens, 1971-, et al.
(författare)
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Sectors of solutions in three-dimensional gravity and black holes
- 2002
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Ingår i: Nuclear Physics B. - : Elsevier. - 0550-3213 .- 1873-1562. ; 628:1-2, s. 331-360
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Tidskriftsartikel (refereegranskat)abstract
- We examine the connection between three dimensional gravity with negative cosmological constant and two-dimensional CFT via the Chern-Simons formulation. A set of generalized spectral flow transformations are shown to yield new sectors of solutions. One implication is that the microscopic calculation of the entropy of the Banados-Teitelboim-Zanelli (BTZ) black hole is corrected by a multiplicative factor with the result that it saturates the Bekenstein-Hawking expression.
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| 9. |
- Lindner, Manfred, et al.
(författare)
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A combined treatment of neutrino decay and neutrino oscillations
- 2001
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Ingår i: Nuclear Physics B. - : Elsevier Science B.V.. - 0550-3213 .- 1873-1562. ; 607:02-jan, s. 326-354
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Tidskriftsartikel (refereegranskat)abstract
- Neutrino decay in vacuum has often been considered as an alternative to neutrino oscillations. Because nonzero neutrino masses imply the possibility of both neutrino decay and neutrino oscillations, we present a model-independent formal treatment of these combined scenarios. For that, we show for the example of Majoron decay that in many cases decay products are observable and may even oscillate. Furthermore, we construct a minimal scenario in which we study the physical implications of neutrino oscillations with intermediate decays.
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| 10. |
- Lindner, Manfred, et al.
(författare)
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Decays of supernova neutrinos
- 2002
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Ingår i: Nuclear Physics B. - : Elsevier Science B.V.. - 0550-3213 .- 1873-1562. ; 622:02-jan, s. 429-456
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Tidskriftsartikel (refereegranskat)abstract
- Supernova neutrinos could be well-suited for probing neutrino decay, since decay may be observed even for very small decay rates or coupling constants. We will introduce an effective operator framework for the combined description of neutrino decay and neutrino oscillations for supernova neutrinos, which can especially take into account two properties: one is the radially symmetric neutrino flux, allowing a decay product to be re-directed towards the observer even if the parent neutrino had a different original direction of propagation. The other is decoherence because of the long baselines for coherently produced neutrinos. We will demonstrate how to use this effective theory to calculate the time-dependent fluxes at the detector. In addition, we will show the implications of a Majoron-like decay model. As a result, we will demonstrate that for certain parameter values one may observe some effects which could also mimic signals similar to the ones expected from supernova models, making it in general harder to separate neutrino and supernova properties.
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