| 1. |
- Fjelstad, Jens, 1971-, et al.
(författare)
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Equivalence of Chern-Simons gauge theory and WZNW model using a BRST symmetry
- 1999
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Ingår i: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 466:2-4, s. 227-233
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Tidskriftsartikel (refereegranskat)abstract
- The equivalence between the Chern-Simons gauge theory on a three-dimensional manifold with boundary and the WZNW model on the boundary is established in a simple and general way using the BRST symmetry. Our approach is based on restoring gauge invariance of the Chern-Simons theory in the presence of a boundary. This gives a correspondence to the WZNW model that does not require solving any constraints, fixing the gauge or specifying boundary conditions.
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| 2. |
- Allasia, D, et al.
(författare)
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Inelastic J ψ production in deep inelastic scattering from hydrogen and deuterium and the gluon distribution of free nucleons
- 1991
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Ingår i: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 258:3-4, s. 493-498
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Tidskriftsartikel (refereegranskat)abstract
- We present results on inelastic J/PSI-production from muon interactions with hydrogen and deuterium at an incident muon energy of 280 GeV. The measured cross section ratio per nucleon for muon-induced J/PSI-production in deuterium and hydrogen was found to be R(D2/H2) = 1.01 +/- 0.15. The colour singlet model is shown to provide a good description of the observed differential cross section apart from a normalisation factor. The comparison between the observed cross section and the colour singlet model prediction allows the extraction of the gluon structure function G(chi) of the nucleon. The momentum fraction-chi of the nucleon carried by the gluon is measured in the range of chi = [0.02, 0.30]. The normalised gluon distribution of free nucleons thus found can be parametrised as chi-G(chi) = 1/2 (eta + 1)(1 - chi)eta, with eta = 5.1 +/- 0.9 (stat).
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| 3. |
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| 4. |
- Amaudruz, P, et al.
(författare)
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Measurements of Rd-Rp and RCa-Rc in deep inelastic muon scattering
- 1992
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Ingår i: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 294:1, s. 120-126
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Tidskriftsartikel (refereegranskat)abstract
- Results are presented on the difference in R, the ratio of longitudinally to transversely polarised virtual photon absorption cross sections, for the deuteron and the proton. They are obtained by comparing the ratio of cross sections for the deep inelastic scattering of muons from deuterium and hydrogen targets at 90 and 280 GeV incident energy. The results cover the range x = 0.01 -0.30, at an average Q2 of 9 GeV2. The measured difference R(d)-R(p) shows no significant x dependence and is compatible with zero, as well as with expectations from perturbative QCD. We use the same method to obtain the difference R(Ca)-R(C) from cross section ratios measured on carbon and calcium targets at 90 and 200 GeV incident energy.
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| 5. |
- Amaudruz, P, et al.
(författare)
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Proton and deuteron F2 structure functions in deep inelastic muon scattering
- 1992
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Ingår i: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 295:1-2, s. 159-168
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Tidskriftsartikel (refereegranskat)abstract
- The structure functions F2p and F2d measured by deep inelastic muon scattering at incident energies of 90 and 280 GeV are presented. These measurements cover a large kinematic range, 0.006 less-than-or-equal-to x less-than-or-equal-to 0.6 and 0.5 less-than-or-equal-to Q2 less-than-or-equal-to 55 GeV2, and include the first precise data at small x, where large scaling violations are observed. The data agree with earlier results from SLAC and BCDMS but exhibit differences with respect to those of EMC-NA2. Extrapolations to small x of recent phenomenological parton distributions are shown to disagree with the present results.
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| 6. |
- Angelopoulos, A., et al.
(författare)
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K 0–KÌ„0 mass and decay-width differences : CPLEAR evaluation
- 1999
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Ingår i: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 471:2, s. 332-338
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Tidskriftsartikel (refereegranskat)abstract
- The CPT-violation parameters Re(δ) and Im(δ) determined recently by CPLEAR are used to evaluate the K0– mass and decay-width differences, as given by the difference between the diagonal elements of the neutral-kaon mixing matrix (M−iΓ/2). The results – GeV and GeV – are consistent with CPT invariance. The CPT invariance is also shown to hold within a few times 10−3–10−4 for many of the amplitudes describing neutral-kaon decays to different final states.
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| 7. |
- Apostolakis, A, et al.
(författare)
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A determination of the CP violation parameter η+- from the decay of strangeness-tagged neutral kaons
- 1999
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Ingår i: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 458:4, s. 545-552
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Tidskriftsartikel (refereegranskat)abstract
- LEAR offered unique opportunities to study the symmetries which exist between matter and antimatter. At variance with other approaches at this facility, CPLEAR was an experiment devoted to the study of CP, T and CPT symmetries in the neutral-kaon system. A variety of measurements allowed us to determine with high precision the parameters which describe the time evolution of the neutral kaons and their antiparticles, including decay amplitudes, and the related symmetry properties. Limits concerning quantum-mechanical predictions (EPR, coherence of the wave function) or the equivalence principle of general relativity have been obtained. An account of the main features of the experiment and its performances is given here, together with the results achieved.
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| 8. |
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| 9. |
- Beausang, C W, et al.
(författare)
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Lifetimes of yrast and excited superdeformed states in Gd-150 : effect of particle-hole excitations on the deformation
- 1998
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Ingår i: Physics Letters B. - 0370-2693 .- 1873-2445. ; 417:1-2, s. 13-19
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Tidskriftsartikel (refereegranskat)abstract
- The quadrupole moments and deformations have been measured for six superdeformed bands in Gd-150. The results indicate evidence for deformation driving properties of both the high-hi intruder and also low-N natural parity states at the superdeformed Fermi surface. Several new transitions have been identified and placed in the low spin non-yrast portion of one of the SD bands.
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| 10. |
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