| 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. |
- 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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| 3. |
- 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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| 4. |
- 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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| 5. |
- 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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| 6. |
- Ohlsson, Tommy, 1973-, et al.
(författare)
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A flavor symmetry model for bilarge leptonic mixing and the lepton masses
- 2002
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Ingår i: Nuclear Physics B. - : Elsevier Science B.V.. - 0550-3213 .- 1873-1562. ; 643:03-jan, s. 247-279
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Tidskriftsartikel (refereegranskat)abstract
- We present a model for leptonic mixing and the lepton masses based on flavor symmetries and higher-dimensional mass operators. The model predicts bilarge leptonic mixing (i.e., the mixing angles theta(12) and theta(23) are large and the mixing angle theta(13) is small) and an inverted hierarchical neutrino mass spectrum. Furthermore, it approximately yields the experimental hierarchical mass spectrum of the charged leptons. The obtained values for the leptonic mixing parameters and the neutrino mass squared differences are all in agreement with atmospheric neutrino data, the Mikheyev-Smirnov-Wolfenstein large mixing angle solution of the solar neutrino problem, and consistent with the upper bound on the reactor mixing angle. Thus, we have a large, but not close to maximal, solar mixing angle theta(12), a nearly maximal atmospheric mixing angle theta(23), and a small reactor mixing angle theta(13). In addition, the model predicts theta(12) similar or equal to pi/4 - theta(13).
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| 7. |
- Amaudruz, P, et al.
(författare)
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A re-evaluation of the nuclear structure function ratios for D, He, 6Li, C and Ca
- 1995
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Ingår i: Nuclear Physics B. - : Elsevier. - 0550-3213 .- 1873-1562. ; 441:1-2, s. 3-11
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Tidskriftsartikel (refereegranskat)abstract
- We present a re-evaluation of the structure function ratios F-2(He)/F-2(D), F-2(C)/F-2(D) and F-2(Ca)/F-2(D) measured in deep inelastic muon-nucleus scattering at an incident muon momentum of 200 GeV. We also present the ratios F-2(C)/F-2(Li), F-2(Ca)/F-2(Li) and F-2(Ca)/F-2(C) measured at 90 GeV. The results are based on data already published by NMC; the main difference in the analysis is a correction for the masses of the deuterium targets and an improvement in the radiative corrections. The kinematic range covered is 0.0035 < x < 0.65, 0.5 < Q(2) < 90 GeV2 for the He/D, C/D and Ca/D data and 0.0085 < x < 0.6, 0.84 < Q(2) < 17 GeV2 for the Li/C/Ca ones.
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| 8. |
- Amaudruz, P, et al.
(författare)
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The ratio F2 n/F2 p in deep inelastic muon scattering
- 1992
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Ingår i: Nuclear Physics B. - : Elsevier. - 0550-3213 .- 1873-1562. ; 371:1-2, s. 3-31
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Tidskriftsartikel (refereegranskat)abstract
- Results are presented on the ratio of neutron and proton structure functions, F2n/F2p, deduced from deep inelastic scattering of muons from hydrogen and deuterium. The data, which were obtained at the CERN muon beam at 90 and 280 GeV incident energy, cover the kinematic range x = 0.002-0.80 and Q2 = 0.1-190 GeV2. The measured structure function ratios have small statistical and systematic errors, particularly at small and intermediate x. The observed Q2 dependence in the range x = 0.1-0.4 is stronger than predicted by perturbative QCD. From the present data together with results from other experiments it is suggested that the twist-four coefficient for the proton is smaller than that for the neutron for x larger than 0.2.
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| 9. |
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| 10. |
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| 11. |
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| 12. |
- Fjelstad, Jens, 1971-, et al.
(författare)
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Logarithmic conformal field theories via logarithmic deformations
- 2002
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Ingår i: Nuclear Physics B. - : Elsevier. - 0550-3213 .- 1873-1562. ; 633:3, s. 379-413
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Tidskriftsartikel (refereegranskat)abstract
- We construct logarithmic conformal field theories starting from an ordinary conformal field theory -- with a chiral algebra C and the corresponding space of states V -- via a two-step construction: i) deforming the chiral algebra representation on V\tensor End K[[z,1/z]], where K is an auxiliary finite-dimensional vector space, and ii) extending C by operators corresponding to the endomorphisms End K. For K=C^2, with End K being the two-dimensional Clifford algebra, our construction results in extending C by an operator that can be thought of as \partial^{-1}E, where \oint E is a fermionic screening. This covers the (2,p) Virasoro minimal models as well as the sl(2) WZW theory.
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| 13. |
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| 14. |
- Fredriksson, Sverker
(författare)
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On large transverse momentum production in high-energy proton-nucleus collisions
- 1976
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Ingår i: Nuclear Physics B. - : Elsevier BV. - 0550-3213 .- 1873-1562. ; 111:1, s. 167-177
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Tidskriftsartikel (refereegranskat)abstract
- Experimental data from inclusive production of large pT hadronsin high-energy proton-nucleus collisions are analysed with emphasis on the influence of the size of the target nucleus. It is found that data at pT≤3 GeV/c are consistent with the hypothesis that the incoming proton collides "simultaneously" with all the nucleons in its way, resulting in an effective collision energy larger than the one expected in a single proton-nucleon hit. At pT > 3 GeV/c, data are in conflict with such a simple model, a result we think is a consequence of the dominance of hard parton collisions at very large pT.
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| 15. |
- Fredriksson, Sverker
(författare)
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Particle ratios in the central region of high-energy proton-proton collisions
- 1975
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Ingår i: Nuclear Physics B. - : Elsevier BV. - 0550-3213 .- 1873-1562. ; 84:1, s. 234-252
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Tidskriftsartikel (refereegranskat)abstract
- Recent data from NAL on particle ratios ... large transverse momentum are analysed with emphasis on the surprising discovery that pions increase their dominance over heavier hadrons at increasing transverse momentum. It is argued that this is not a phase space or threshold effect but a dynamical feature that can be used to test theoretical models of multiparticle production. Most models of interest, such as for instance the parton, the hydrodynamical and the two-component model, may however be extended, in a simple-minded way, to kaon and antiproton production as to predict ratios of heavier to lighter hadrons to fall with increasing large transverse momentum.
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| 16. |
- Frohlich J,, et al.
(författare)
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Asymptotic form of zero energy wave functions in supersymmetric matrix models
- 2000
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Ingår i: Nuclear Physics B. - 0550-3213 .- 1873-1562. ; 567:1-2, s. 231-248
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Tidskriftsartikel (refereegranskat)abstract
- We derive the power law decay, and asymptotic form, of SU(2) X Spin(d) invariant wavefunctions satisfying Q(beta)psi=0 for all s(d) = 2(d - 1) supercharges of reduced (d + 1)-dimensional supersymmetric SU(2) Yang-Mills theory, of, respectively, the SU(2) matrix model related to supermembranes in d + 2 dimensions.
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| 17. |
- Grosse, H., et al.
(författare)
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Chiral Schwinger models without gauge anomalies
- 2000
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Ingår i: Nuclear Physics B. - 0550-3213 .- 1873-1562. ; 587:03-jan, s. 568-584
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Tidskriftsartikel (refereegranskat)abstract
- We find a large class of quantum gauge models with massless fermions where the coupling to the gauge fields is not chirally symmetric and which nevertheless do not suffer from gauge anomalies. To be specific we study two dimensional Abelian models in the Hamiltonian framework which can be constructed and solved by standard techniques. The general model describes Np photon fields and NF flavors of Dirac fermions with 2N(F)N(P) different coupling constants, i.e., the chiral component of each fermion can he coupled to the gauge fields differently We construct these models and find conditions so that no gauge anomaly appears. If these conditions hold it is possible to construct and solve the model explicitly, so that gauge- and Lorentz invariance are manifest.
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| 18. |
- Hoppe, Jens, et al.
(författare)
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Dimensionally reduced SYM4 as solvable matrix quantum mechanics
- 2000
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Ingår i: Nuclear Physics B. - 0550-3213 .- 1873-1562. ; 571:1-2, s. 479-509
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Tidskriftsartikel (refereegranskat)abstract
- We study the quantum mechanical model obtained as a dimensional reduction of N = 1 super Yang-Mills theory to a periodic light cone "time''. After mapping the theory to a cohomological field theory, the partition function (with periodic boundary conditions) regularized by a massive term appears to be equal to the partition function of the twisted matrix oscillator. We show that this partition function perturbed by the operator of the holonomy around the time circle is a tau function of Toda hierarchy. We solve the model in the large N limit and study the universal properties of the solution in the scaling limit of vanishing perturbation. We find in this limit a phase transition of Gross-Witten type.
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| 19. |
- Langmann, Edwin
(författare)
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Interacting fermions on non-commutative spaces: Exactly solvable quantum field theories in 2n+1 dimensions
- 2003
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Ingår i: Nuclear Physics B. - : Elsevier. - 0550-3213 .- 1873-1562. ; 654:3, s. 404-426
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Tidskriftsartikel (refereegranskat)abstract
- I present a novel class of exactly solvable quantum field theories. They describe non-relativistic fermions on even-dimensional flat space, coupled to a constant external magnetic field and a four point interaction defined with the Groenewold-Moyal star product. Using Hamiltonian quantization and a suitable regularization, I show that these models have a dynamical symmetry corresponding to gl(infinity) circle plus gl(infinity) at the special points Btheta = I and Btheta = -I, where B and theta are the matrices defining the magnetic field and the star product, respectively. I construct all eigenvalues and eigenstates, of the many-body Hamiltonian at these special points. I argue that this solution cannot be obtained by any mean-field theory, i.e., the models describe correlated fermions. I also mention other possible interpretations of these models in solid state physics.
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| 20. |
- Matsubara, Keizo, et al.
(författare)
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Opens strings in simple current orbifolds
- 2002
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Ingår i: Nuclear Physics B. - 0550-3213 .- 1873-1562. ; 626:1-2, s. 53-72
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Tidskriftsartikel (refereegranskat)abstract
- We study branes and open strings in a large class of orbifold backgrounds using microscopic techniques of boundary conformal field theory. In particular, we obtain factorizing operator product expansions of open string vertex operators for such branes. Applications include branes in orbifolds of the SU(2) WZW model and in the D-series of unitary minimal models considered previously by Runkel.
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| 21. |
- Rubinstein, Hector R., et al.
(författare)
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Dependence of lattice hadron masses on external magnetic fields
- 1995
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Ingår i: Nuclear Physics B. - : Elsevier BV. - 0550-3213 .- 1873-1562. ; 457:3, s. 577-593
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Tidskriftsartikel (refereegranskat)abstract
- We study the variation of the hadron masses in the presence of external magnetic fields of strength of the order of the masses themselves.We identify the main factors affecting the lattice simulation results:•- the boundary discontinuities for eB ⪡ 2π/L2a2.•- the SU(6) choice of the hadron wave function.We confirm qualitatively the earlier theoretical ansatz on the linear behaviour of the masses with the magnetic field and, as a by-product, we improve the lattice measurements of the nucleon magnetic moments.However our systematic and statistical errors preclude us from measuring the theoretically predicted field strength at which the proton becomes heavier than the neutron.
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| 22. |
- Aartsen, M. G., et al.
(författare)
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Neutrino oscillation studies with IceCube-DeepCore
- 2016
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Ingår i: Nuclear Physics B. - : Elsevier BV. - 0550-3213 .- 1873-1562. ; 908, s. 161-177
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Tidskriftsartikel (refereegranskat)abstract
- IceCube, a gigaton-scale neutrino detector located at the South Pole, was primarily designed to search for astrophysical neutrinos with energies of PeV and higher. This goal has been achieved with the detection of the highest energy neutrinos to date. At the other end of the energy spectrum, the DeepCore extension lowers the energy threshold of the detector to approximately 10 GeV and opens the door for oscillation studies using atmospheric neutrinos. An analysis of the disappearance of these neutrinos has been completed, with the results produced being complementary with dedicated oscillation experiments. Following a review of the detector principle and performance, the method used to make these calculations, as well as the results, is detailed. Finally, the future prospects of IceCube-DeepCore and the next generation of neutrino experiments at the South Pole (IceCube-Gen2, specifically the PINGU sub-detector) are briefly discussed.
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| 23. |
- Abdelalim, Ahmed Ali, et al.
(författare)
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Di-photon decay of a light Higgs state in the BLSSM
- 2022
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Ingår i: Nuclear Physics B. - : Elsevier. - 0550-3213 .- 1873-1562. ; 985
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Tidskriftsartikel (refereegranskat)abstract
- In the context of the B - L Supersymmetric Standard Model (BLSSM), we investigate the consistency of a scenario with a light Higgs boson with mass in the range 94 - 98 GeV and a Standard Model (SM) Higgs state at 125 GeV with the results of a search performed by the CMS Collaboration in the di-photon channel primarily involving data at an integrated luminosity of 35.9 fb-1 and an energy of root s = 13 TeV. In this study, we present a Monte Carlo (MC) analysis of signal and background mimicking the experimental one and showing acceptable consistency with data, at both the integral and differential level.(c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP3.
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| 24. |
- Abulaiti, Yiming, et al.
(författare)
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High-E-T isolated-photon plus jets production in pp collisions at root s=8 TeV with the ATLAS detector
- 2017
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Ingår i: Nuclear Physics B. - : Elsevier BV. - 0550-3213 .- 1873-1562. ; 918, s. 257-316
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Tidskriftsartikel (refereegranskat)abstract
- The dynamics of isolated-photon plus one-, two- and three-jet production in pp collisions at a centre-of-mass energy of 8 TeV are studied with the ATLAS detector at the LHC using a data set with an integrated luminosity of 20.2 fb(-1). Measurements of isolated-photon plus jets cross sections are presented as functions of the photon and jet transverse momenta. The cross sections as functions of the azimuthal angle between the photon and the jets, the azimuthal angle between the jets, the photon-jet invariant mass and the scattering angle in the photon-jet centre-of-mass system are presented. The pattern of QCD radiation around the photon and the leading jet is investigated by measuring jet production in an annular region centred on each object; enhancements are observed around the leading jet with respect to the photon in the directions towards the beams. The experimental measurements are compared to several different theoretical calculations, and overall a good description of the data is found.
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| 25. |
- Abulaiti, Yiming, et al.
(författare)
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Measurement of D-*+/-, D-+/- and D-S(+/-) meson production cross sections in pp collisions at root s=7 TeV with the ATLAS detector
- 2016
-
Ingår i: Nuclear Physics B. - : Elsevier BV. - 0550-3213 .- 1873-1562. ; 907, s. 717-763
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Tidskriftsartikel (refereegranskat)abstract
- The production of D*(+/-), D-+/- and D-S(+/-) charmed mesons has been measured with the ATLAS detector in pp collisions at,/7s = 7 TeV at the LHC, using data corresponding to an integrated luminosity of 280 nb(-)1(.) The charmed mesons have been reconstructed in the range of transverse momentum 3.5 < p(T)(D) < 100 GeV and pseudorapidity vertical bar eta(D)vertical bar < 2.1. The differential cross sections as a function of transverse momentum and pseudorapidity were measured for D*(+/-) and D-+/- production. The next-to-leading-order QCD predictions are consistent with the data in the visible kinematic region within the large theoretical uncertainties. Using the visible D cross sections and an extrapolation to the full kinematic phase space, the strangeness -suppression factor in charm fragmentation, the fraction of charged non -strange D mesons produced in a vector state, and the total cross section of charm production at root s = 7 TeV were derived.
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| 26. |
- Adolphi, C., et al.
(författare)
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Exclusive omega meson muoproduction on transversely polarised protons
- 2017
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Ingår i: Nuclear Physics B. - : ELSEVIER SCIENCE BV. - 0550-3213 .- 1873-1562. ; 915, s. 454-475
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Tidskriftsartikel (refereegranskat)abstract
- Exclusive production of omega mesons was studied at the COMPASS experiment by scattering 160GeV/c muons off transversely polarised protons. Five single-spin and three double-spin azimuthal asymmetries were measured in the range of photon virtuality 1(GeV/c)(2) < Q(2) < 10(GeV/c)(2), Bjorken scaling variable 0.003 < xBj < 0.3 and transverse momentum squared of the omega meson 0.05(GeV/c)(2) < p(T)(2) < 0.5(GeV/c)(2). The measured asymmetries are sensitive to the nucleon helicity-flip Generalised Parton Distributions (GPD) Et hat are related to the orbital angular momentum of quarks, the chiral-odd GPDs H-T that are related to the transversity Parton Distribution Functions, and the sign of the pi omega transition form factor. The results are compared to recent calculations of a GPD-based model.
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| 27. |
- Ahmadiniaz, Naser, et al.
(författare)
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Manifest colour-kinematics duality and double-copy in the string-based formalism
- 2022
-
Ingår i: Nuclear Physics B. - : Elsevier. - 0550-3213 .- 1873-1562. ; 975
-
Tidskriftsartikel (refereegranskat)abstract
- The relation for the gravity polarisation tensor as the tensor product of two gluon polarisation vectors has been well-known for a long time, but a version of this relation for multi-particle fields is presently still not known. Here we show that in order for this to happen we first have to ensure that the multi-particle polarisations satisfy colour-kinematics duality. In previous work it has been show that this arises naturally from the Bern-Kosower formalism for one-loop gluon amplitudes, and here we show that the tensor product for multi-particle fields arises naturallyin the Bern-Dunbar-Shimada formalism for one-loop gravity amplitudes. This allows us to formulate a new prescription for double-copy gravity Berends-Giele currents, and to obtain both the colour-dressed Yang-Mills Berends-Giele currents in the Bern-Carrasco-Johansson gauge and the gravitational Berends-Giele currents explicitly. An attractive feature of our formalism is that it never becomes necessary to determine gauge transformation terms. Our double-copy prescription can also be applied to other cases, and to make this point we derive the double-copy perturbiners for alpha'-deformed gravity and the bi-adjoint scalar model. (C) 2022 The Author(s). Published by Elsevier B.V.
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| 28. |
- Anastasiou, Alexandros, et al.
(författare)
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Are all supergravity theories Yang-Mills squared?
- 2018
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Ingår i: Nuclear Physics B. - : Elsevier. - 0550-3213 .- 1873-1562. ; 934, s. 606-633
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Tidskriftsartikel (refereegranskat)abstract
- Using simple symmetry arguments we classify the ungauged D = 4, N = 2 supergravity theories, coupled to both vector and hyper multiplets through homogeneous scalar manifolds, that can be built as the product of N = 2 and N= 0 matter-coupled Yang-Mills gauge theories. This includes all such supergravities with two isolated exceptions: pure supergravity and the T-3 model.
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| 29. |
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| 30. |
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| 31. |
- Antusch, Stefan, et al.
(författare)
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Perturbative estimates of lepton mixing angles in unified models
- 2009
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Ingår i: Nuclear Physics B. - : Elsevier BV. - 0550-3213 .- 1873-1562. ; 820:1-2, s. 32-46
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Tidskriftsartikel (refereegranskat)abstract
- Many unified models predict two large neutrino mixing angles, with the charged lepton mixing angles being small and quark-like, and the neutrino masses being hierarchical. Assuming this, we present simple approximate analytic formulae giving the lepton mixing angles in terms of the underlying high energy neutrino mixing angles together with small perturbations due to both charged lepton corrections and renormalisation group (RG) effects, including also the effects of third family canonical normalization (CN). We apply the perturbative formulae to the ubiquitous case of tri-bimaximal neutrino mixing at the unification scale, in order to predict the theoretical corrections to mixing angle predictions and sum rule relations, and give a general discussion of all limiting cases. We also discuss the implications for the sum rule relations of the measurement of a non-zero reactor angle, as hinted at by recent experimental measurements.
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| 32. |
- Astolfi, Davide, et al.
(författare)
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Finite-size corrections in the SU(2)×SU(2) sector of type IIA string theory on AdS4 x CP3
- 2009
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Ingår i: Nuclear Physics B. - : Elsevier BV. - 0550-3213 .- 1873-1562. ; 810:1-2, s. 150-173
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Tidskriftsartikel (refereegranskat)abstract
- We consider finite-size corrections in the SU(2)×SU(2) sector of type IIA string theory on , which is the string dual of the recently constructed superconformal Chern–Simons theory of Aharony, Bergman, Jafferis and Maldacena (ABJM theory). The string states we consider are in the subspace of with an angular momentum J on being large. We compute the finite-size corrections using two different methods, one is to consider curvature corrections to the Penrose limit giving an expansion in1/J, the other by considering a low energy expansion in λ′=λ/J2 of the string theory sigma-model, λ being the 't Hooft coupling of the dual ABJM theory. For both methods there are interesting issues to deal with. In the near-pp-wave method there is a interaction term for which we use zeta-function regularization in order to compute the 1/J correction to the energy. For the low energy sigma-model expansion we have to take into account a non-trivial coupling to a non-dynamical transverse direction. We find agreement between the two methods. At order λ′ and , for small λ′, our results are analogous to the ones for the SU(2) sector in type IIB string theory on AdS5×S5. Instead at order there are interactions between the two two-spheres. We compare our results with the recently proposed all-loop Bethe ansatz of Gromov and Vieira and find agreement.
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| 33. |
- Babaev, Egor
(författare)
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Phase diagram of planar U(l) x U(l) superconductor - Condensation of vortices with fractional flux and a superfluid state
- 2004
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Ingår i: Nuclear Physics B. - : Elsevier BV. - 0550-3213 .- 1873-1562. ; 686:3, s. 397-412
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Tidskriftsartikel (refereegranskat)abstract
- We discuss a phase diagram of two-dimensional U(1) x U(l) superconductor in the field theoretic formalizm of [Phys. Rev. Lett. 89 (2002) 067001]. In particular we discuss that when penetration length is short the system exhibit a quasi-neutral quasi-superfluid state which is a state when quasi-long range order sets in only in phase difference while individually the phases are disordered.
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| 34. |
- Bauer, F., et al.
(författare)
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Discretized gravity in 6D warped space
- 2007
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Ingår i: Nuclear Physics B. - : Elsevier BV. - 0550-3213 .- 1873-1562. ; 278:1-3, s. 32-63
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Tidskriftsartikel (refereegranskat)abstract
- We consider discretized gravity in six dimensions. where the two extra dimensions have been compactified on a hyperbolic disk of constant curvature. We analyze different realizations of lattice gravity on the disk at the level of an effective field theory for massive gravitons. It is shown that the observed strong coupling scale of lattice gravity in discretized five-dimensional flat or warped space can be increased if the latticized fifth dimension is wrapped around a hyperbolic disk that has a non-trivial warp factor. As an application, we also study the generation of naturally small Dirac neutrino masses via a discrete volume suppression mechanism and discuss briefly collider implications of our model.
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| 35. |
- Baussan, E., et al.
(författare)
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A very intense neutrino super beam experiment for leptonic CP violation discovery based on the European spallation source linac
- 2014
-
Ingår i: Nuclear Physics B. - : Elsevier BV. - 0550-3213 .- 1873-1562. ; 885, s. 127-149
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Tidskriftsartikel (refereegranskat)abstract
- Very intense neutrino beams and large neutrino detectors will be needed in order to enable the discovery of CP violation in the leptonic sector. We propose to use the proton linac of the European Spoliation Source currently under construction in Lund, Sweden, to deliver, in parallel with the spoliation neutron production, a very intense, cost effective and high performance neutrino beam. The baseline program for the European Spoliation Source linac is that it will be fully operational at 5 MW average power by 2022, producing 2 GeV 2.86 ms long proton pulses at a rate of 14 Hz. Our proposal is to upgrade the linac to 10 MW average power and 28 Hz, producing 14 pulses/s for neutron production and 14 pulses/s for neutrino production. Furthermore, because of the high current required in the pulsed neutrino horn, the length of the pulses used for neutrino production needs to be compressed to a few mu s with the aid of an accumulator ring. A long baseline experiment using this Super Beam and a megaton underground Water Cherenkov detector located in existing mines 300-600 km from Lund will make it possible to discover leptonic CP violation at 5 sigma significance level in up to 50% of the leptonic Dirac CP-violating phase range. This experiment could also determine the neutrino mass hierarchy at a significance level of more than 3 sigma if this issue will not already have been settled by other experiments by then. The mass hierarchy performance could be increased by combining the neutrino beam results with those obtained from atmospheric neutrinos detected by the same large volume detector. This detector will also be used to measure the proton lifetime, detect cosmological neutrinos and neutrinos from supernova explosions. Results on the sensitivity to leptonic CP violation and the neutrino mass hierarchy are presented.
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| 36. |
- Beiming, Christoffer, et al.
(författare)
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Phenomenological mass model for exotic hadrons and predictions for masses of non-strange dibaryons as hexaquarks
- 2022
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Ingår i: Nuclear Physics B. - : Elsevier BV. - 0550-3213 .- 1873-1562. ; 974, s. 115616-
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the mass spectra of exotic hadrons known as hexaquarks in the form of dibaryons. We use a phenomenological model based on an extended version of the Giirsey-Radicati mass formula for hadrons to include non-charmed baryons, charmed baryons, and non-strange dibaryons to be able to predict masses of potential dibaryon states. We perform six numerical fits of this model to input data for three different sets of masses of baryons and dibaryons. We find that the model can fit some of the data sets well, especially the sets including charmed baryons and non-strange dibaryons, and observe that the predicted mass of one of the dibaryons is close to the measured mass of the observed hexaquark candidate d * (2380) reported by the WASA-at-COSY experiment. The predicted mass of the deuteron is slightly larger than its measured mass. Finally, for the data sets including charmed baryon and non-strange dibaryon masses, we find that the predicted masses of potential dibaryon states are all in the range from 1900 MeV to 3700 MeV.
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| 37. |
- Bjornsson, Jonas, et al.
(författare)
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Gauged non-compact WZNW models, revisited
- 2010
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Ingår i: Nuclear Physics B. - : Elsevier. - 0550-3213 .- 1873-1562. ; 832:1-2, s. 52-88
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of the present paper is to investigate the necessary conditions for unitarity of the spectrum of non-compact gauged WZNW models to some depth. In particular, we would like to investigate the necessity of integer weights and level. We will learn that the problem is very complex and we have not found any simple and general way to formulate the necessary conditions. Instead one must resort to studying the problem almost case by case. The only nearly complete conditions that we will find, is for the case g = su(n, 1). Furthermore, the horizontal part of the case g = su(p, g) is nearly completed as well. In other cases, we will find conditions associated with certain subalgebras and nodes in the Dynkin diagram close to the one corresponding to the non-compact root. In these examples we can give conditions for the horizontal part of the algebra. As a by-product of our investigation we will prove some nice formulae of character identities and explicit branching functions for these representations. (C) 2010 Elsevier B.V. All rights reserved.
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| 38. |
- Björnsson, Jonas, 1980-, et al.
(författare)
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On the unitarity of gauged non-compact world-sheet supersymmetric WZNW models
- 2009
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Ingår i: Nuclear Physics B. - : Elsevier BV. - 0550-3213 .- 1873-1562. ; 812:3, s. 525-539
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we generalize our investigation of the unitarity of non-compact WZNW models connected to Hermitian symmetric spaces to the N=1 world-sheet supersymmetric extension of these models. We will prove that these models have a unitary spectrum in a BRST approach for antidominant highest weight representations if the level and weights of the gauged subalgebra are integers. We will find new critical string theories in 7 and 9 space–time dimensions.
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| 39. |
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| 40. |
- Björnsson, Jonas, et al.
(författare)
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Stretched Quantum Membranes
- 2005
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Ingår i: Nuclear Physics B727 (2005) 77-98. - : Elsevier BV. ; 727:1-2, s. 77-98
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Tidskriftsartikel (refereegranskat)
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| 41. |
- Björnsson, Jonas, et al.
(författare)
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The BRST treatment of stretched membranes
- 2006
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Ingår i: Nuclear Physics B736 (2006) 156-167. - : Elsevier BV. ; 736:1-2, s. 156-167
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Tidskriftsartikel (refereegranskat)
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| 42. |
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| 43. |
- Blaksley, Carl, et al.
(författare)
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Heavy neutrinos and lepton number violation in ℓp colliders
- 2011
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Ingår i: Nuclear Physics B. - : Elsevier BV. - 0550-3213 .- 1873-1562. ; 852:2, s. 353-365
-
Tidskriftsartikel (refereegranskat)abstract
- We discuss the prospects of studying lepton number violating processes in order to identify Majorana neutrinos from low scale seesaw mechanisms at lepton-proton colliders. In particular, we consider the scenarios of colliding electrons with LHC energy protons and, motivated by the efforts towards the construction of a muon collider, the prospects of muon-proton collisions. We find that present constraints on the mixing of the Majorana neutrinos still allow for a detectable signal at these kind of facilities given the smallness of the Standard Model background. We discuss possible cuts in order to further increase the signal over background ratio and the prospects of reconstructing the neutrino mass from the kinematics of the final state particles.
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| 44. |
- Borsato, Riccardo, et al.
(författare)
-
q-Poincaré supersymmetry in AdS5/CFT4
- 2018
-
Ingår i: Nuclear Physics B. - : Elsevier B.V.. - 0550-3213 .- 1873-1562. ; 928, s. 321-355
-
Tidskriftsartikel (refereegranskat)abstract
- We consider the exact S-matrix governing the planar spectral problem for strings on AdS5×S5 and N=4 super Yang–Mills, and we show that it is invariant under a novel “boost” symmetry, which acts as a differentiation with respect to the particle momentum. This generator leads us also to reinterpret the usual centrally extended psu(2|2) symmetry, and to conclude that the S-matrix is invariant under a q-Poincaré supersymmetry algebra, where the deformation parameter is related to the ‘t Hooft coupling. We determine the two-particle action (coproduct) that turns out to be non-local, and study the property of the new symmetry under crossing transformations. We look at both the strong-coupling (large tension in the string theory) and weak-coupling (spin-chain description of the gauge theory) limits; in the former regime we calculate the cobracket utilising the universal classical r-matrix of Beisert and Spill. In the eventuality that the boost has higher partners, we also construct a quantum affine version of 2D Poincaré symmetry, by contraction of the quantum affine algebra Uq(sl2ˆ) in Drinfeld's second realisation.
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| 45. |
- Bredthauer, Andreas
(författare)
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Generalized hyperkaehler geometry and supersymmetry
- 2007
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Ingår i: Nuclear Physics B. - : Elsevier BV. - 0550-3213 .- 1873-1562. ; 773:3, s. 172-183
-
Tidskriftsartikel (refereegranskat)abstract
- We propose the definition of (twisted) generalized hyper-Kähler geometry and its relation to supersymmetric non-linear sigma models. We also construct the corresponding twistor space.
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| 46. |
- Cagnazzo, Alessandra, et al.
(författare)
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Spectra of sigma models on semi-symmetric spaces
- 2016
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Ingår i: Nuclear Physics B. - : Elsevier. - 0550-3213 .- 1873-1562. ; 906, s. 342-366
-
Tidskriftsartikel (refereegranskat)abstract
- Sigma models on semi-symmetric spaces provide the central building block for string theories on AdS backgrounds. Under certain conditions on the global supersymmetry group they can be made one-loop conformal by adding an appropriate fermionic Wess-Zumino term. We determine the full one-loop dilation operator of the theory. It involves an interesting new XXZ-like interaction term. Eigenvalues of our dilation operator, i.e. the one-loop anomalous dimensions, are computed for a few examples.
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| 47. |
- Carmelo, J M P, et al.
(författare)
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Finite-energy spectral-weight distributions of a 1D correlated metal
- 2005
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Ingår i: Nuclear Physics B. - Amsterdam : Elsevier. - 0550-3213 .- 1873-1562. ; 725:3, s. 421-466
-
Tidskriftsartikel (refereegranskat)abstract
- We derive general closed-form analytical expressions for the finite-energy one- and two-electron spectral-weight distributions of an one-dimensional correlated metal with on-site electronic repulsion. Our results also provide general expressions for the one- and two-atom spectral functions of a correlated quantum system of cold fermionic atoms in a one-dimensional optical lattice with onsite atomic repulsion. In the limit of zero spin density our spectral-function expressions provide the correct zero-spin density results. Our results reveal the dominant non-perturbative microscopic many-particle mechanisms behind the exotic spectral properties observed in quasi-one-dimensional metals and correlated systems of cold fermionic atoms in one-dimensional optical lattices. (c) 2005 Elsevier B.V. All rights reserved.
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| 48. |
- Castro-Alvaredo, Olalla A., et al.
(författare)
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On the representation of minimal form factors in integrable quantum field theory
- 2024
-
Ingår i: Nuclear Physics B. - : Elsevier BV. - 0550-3213 .- 1873-1562. ; 1000, s. 116459-
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, we propose a new representation of the minimal form factors in integrable quantum field theories. These are solutions of the two-particle form factor equations, which have no poles on the physical sheet. Their expression constitutes the starting point for deriving higher particle form factors and, from these, the correlation functions of the theory. As such, minimal form factors are essential elements in the analysis of integrable quantum field theories. The proposed new representation arises from our recent study of form factors in TT‾-perturbed theories, where we showed that the minimal form factors decompose into elementary building blocks. Here, focusing on the paradigmatic sinh-Gordon model, we explicitly express the standard integral representation of the minimal form factor as a combination of infinitely many elementary terms, each representing the minimal form factor of a generalised TT‾ perturbation of the free fermion. Our results can be readily extended to other integrable quantum field theories and open various relevant questions and discussions, from the efficiency of numerical methods in evaluating correlation functions to the foundational question of what constitutes a “reasonable” choice for the minimal form factor.
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| 49. |
- Chemissany, Wissam, et al.
(författare)
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Black holes as generalised Toda molecules
- 2011
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Ingår i: Nuclear Physics B. - : Elsevier BV. - 0550-3213 .- 1873-1562. ; 843, s. 413-428
-
Tidskriftsartikel (refereegranskat)abstract
- In this note we compare the geodesic formalism for spherically symmetric black hole solutions with the black hole effective potential approach. The geodesic formalism is beneficial for symmetric supergravity theories since the symmetries of the larger target space leads to a complete set of commuting constants of motion that establish the integrability of the geodesic equations of motion, as shown in arXiv:1007.3209. We point out that the integrability lifts straightforwardly to the integrability of the equations of motion with a black hole potential. This construction turns out to be a generalisation of the connection between Toda molecule equations and geodesic motion on symmetric spaces known in the mathematics literature. We describe in some detail how this generalisation of the Toda molecule equations arises.
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| 50. |
- Chemissany, Wissam, et al.
(författare)
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The Full integration of black hole solutions to symmetric supergravity theories
- 2010
-
Ingår i: Nuclear Physics B. - : Elsevier BV. - 0550-3213 .- 1873-1562.
-
Tidskriftsartikel (refereegranskat)abstract
- We prove that all stationary and spherical symmetric black hole solutions to theories with symmetric target spaces are integrable and we provide an explicit integration method. This exact integration is based on the description of black hole solutions as geodesic curves on the moduli space of the theory when reduced over the timelike direction. These geodesic equations of motion can be rewritten as a specific Lax pair equation for which mathematicians have provided the integration algorithms when the initial conditions are described by a diagonalizable Lax matrix. We comment on BPS versus non-BPS extremal black holes in this setup. The explicit details, such as a full integration of the STU-model and the non-diagonalizable integration algorithm, is left for a future work and instead some simple examples to illustrate our point are presented.
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