| 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
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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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