| 51. |
- Bergshoeff, E. A., et al.
(författare)
-
E10 and gauged maximal supergravity
- 2009
-
Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479 .- 1126-6708. ; 2009:1, s. 020 (artno)-
-
Tidskriftsartikel (refereegranskat)abstract
- We compare the dynamics of maximal three-dimensional gauged supergravity in appropriate truncations with the equations of motion that follow from a one-dimensional E10/K(E-10) coset model at the first few levels. The constant embedding tensor, which describes gauge deformations and also constitutes an M-theoretic degree of freedom beyond eleven-dimensional supergravity, arises naturally as an integration constant of the geodesic model. In a detailed analysis, we find complete agreement at the lowest levels. At higher levels there appear mismatches, as in previous studies. We discuss the origin of these mismatches.
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| 52. |
- Biggio, Carla, et al.
(författare)
-
General bounds on non-standard neutrino interactions
- 2009
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- We derive model-independent bounds on production and detection nonstandard neutrino interactions (NSI). We find that the constraints for NSI parameters are around O (10(-2)) to O (10(-1)). Furthermore, we review and update the constraints on matter NSI. We conclude that the bounds on production and detection NSI are generally one order of magnitude stronger than their matter counterparts.
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| 53. |
- Biggio, Carla, et al.
(författare)
-
Loop bounds on non-standard neutrino interactions
- 2009
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :3
-
Tidskriftsartikel (refereegranskat)abstract
- We reconsider the bounds on non-standard neutrino interactions with matter which can be derived by constraining the four-charged-lepton operators induced at the loop level. We find that these bounds are model dependent. Naturalness arguments can lead to much stronger constraints than those presented in previous studies, while no completely model-independent bounds can be derived. We will illustrate how large loop-contributions to four-charged-lepton operators are induced within a particular model that realizes gauge invariant non-standard interactions and discuss conditions to avoid these bounds. These considerations mainly affect the O(10(-4)) constraint on the non-standard coupling strength epsilon e(mu), which is lost. The only model-independent constraints that can be derived are O(10(-1)). However, significant cancellations are required in order to saturate this bound.
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| 54. |
- Bonelli, Giulio, et al.
(författare)
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Computing amplitudes in topological M-theory
- 2007
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :3, s. 023-
-
Tidskriftsartikel (refereegranskat)abstract
- We define a topological quantum membrane theory on a seven dimensionalmanifold of G2 holonomy. We describe in detail the path integral evaluation for membranegeometries given by circle bundles over Riemann surfaces. We show that when the targetspace is CY3 × S 1 quantum amplitudes of non-local observables of membranes wrappingthe circle reduce to the A-model amplitudes. In particular for genus zero we show thatour model computes the Gopakumar-Vafa invariants. Moreover, for membranes wrappingcalibrated homology spheres in the CY3 , we find that the amplitudes of our model arerelated to Joyce invariants.
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| 55. |
- Conrad, Jan, et al.
(författare)
-
Applying rule ensembles to the search for super-symmetry at the Large Hadron Collider
- 2006
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :7, s. 040-
-
Tidskriftsartikel (refereegranskat)abstract
- In this note we give an example application of a recently presented predictive learning method called Rule Ensembles. The application we present is the search for super-symmetric particles at the Large Hadron Collider. In particular, we consider the problem of separating the background coming from top quark production from the signal of super-symmetric particles. The method is based on an expansion of base learners, each learner being a rule, i.e. a combination of cuts in the variable space describing signal and background. These rules are generated from an ensemble of decision trees. One of the results of the method is a set of rules (cuts) ordered according to their importance, which gives useful tools for diagnosis of the model. We also compare the method to a number of other multivariate methods, in particular Artificial Neural Networks, the likelihood method and the recently presented boosted decision tree method. We find better performance of Rule Ensembles in all cases. For example for a given significance the amount of data needed to claim SUSY discovery could be reduced by 15% using Rule Ensembles as compared to using a likelihood method.
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| 56. |
- Constantinou, Martha, et al.
(författare)
-
(a 2) corrections to the one-loop propagator and bilinears of clover fermions with Symanzik improved gluons
- 2009
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- We calculate corrections to the fermion propagator and to the Green's functions of all fermion bilinear operators of the form , to one-loop in perturbation theory. We employ the Wilson/clover action for fermions and the Symanzik improved action for gluons. The novel aspect of our calculations is that they are carried out to second order in the lattice spacing, (a 2). Consequently, they have addressed a number of new issues, most notably the appearance of loop integrands with strong IR divergences (convergent only beyond 6 dimensions). Such integrands are not present in (a 1) improvement calculations; there, IR divergent terms are seen to have the same structure as in the (a 0) case, by virtue of parity under integration, and they can thus be handled by well-known techniques. We explain how to correctly extract the full (a 2) dependence; in fact, our method is generalizable to any order in a. The (a 2) corrections to the quark propagator and Green's functions computed in this paper are useful to improve the nonperturbative RI-MOM determination of renormalization constants for quark bilinear operators. Our results depend on a large number of parameters: coupling constant, number of colors, lattice spacing, external momentum, clover parameter, Symanzik coefficients, gauge parameter. To make these results most easily accessible to the reader, we have included them in the distribution package of this paper, as an ASCII file named: Oa2results.m; the file is best perused as Mathematica input
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| 57. |
- Danielsson, Ulf H., et al.
(författare)
-
Towards classical de Sitter solutions in string theory
- 2009
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :9, s. 114-
-
Tidskriftsartikel (refereegranskat)abstract
- We investigate the type II string effective potential at tree-level for de Sitter critical points. We derive necessary ingredients for having de Sitter solutions in orientifold models with fluxes. Furthermore, we examine some explicit O6 compactifications in IIA theory on manifolds with SU(3)-structure in the limit where the orientifold sources are smeared. In particular, we use a simple ten-dimensional Ansatz for four-dimensional de Sitter solutions and find the explicit criteria in terms of the torsion classes such that these de Sitter solutions solve the equations of motion. We have verified these torsion conditions for the cosets and the Iwasawa manifold and it turns out that the conditions cannot be fulfilled for these spaces. However this investigation allows us to find new non-supersymmetric AdS solutions for some cosets. It remains an open question whether there exist SU(3)-structure manifolds that satisfy the conditions on the torsion classes for the simple de Sitter solutions to exist.
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| 58. |
- Danielsson, Ulf, et al.
(författare)
-
The world next door: Results in landscape topography
- 2007
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; 03, s. 080-
-
Tidskriftsartikel (refereegranskat)abstract
- Recently, it has become clear that neighboring multiple vacua might have interesting consequences for the physics of the early universe. In this paper we investigate the topography of the string landscape corresponding to complex structure moduli of flux compactified type IIB string theory. We find that series of continuously connected vacua are common. The properties of these series are described, and we relate the existence of infinite series of minima to certain unresolved mathematical problems in group theory. Numerical studies of the mirror quintic serve as illustrating examples.
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| 59. |
- Elvang, Henriette, et al.
(författare)
-
Proof of the MHV vertex expansion for all tree amplitudes in N=4 SYM theory
- 2009
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479.
-
Tidskriftsartikel (refereegranskat)abstract
- We prove the MHV vertex expansion for all tree amplitudes of N=4 SYM theory. The proof uses a shift acting on all external momenta, and we show that every N^kMHV tree amplitude falls off as 1/z^k, or faster, for large z under this shift. The MHV vertex expansion allows us to derive compact and efficient generating functions for all N^kMHV tree amplitudes of the theory. We also derive an improved form of the anti-NMHV generating function. The proof leads to a curious set of sum rules for the diagrams of the MHV vertex expansion.
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| 60. |
- Elvang, Henriette, et al.
(författare)
-
Semi-Direct Gauge Mediation with the 4-1 Model
- 2009
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479.
-
Tidskriftsartikel (refereegranskat)abstract
- We analyze a model of Semi-Direct Gauge Mediation in which the hidden sector is the 4-1 model and the messenger fields are charged under the U(1) gauge group. At tree level, the SUSY-breaking F-terms induce D-terms from which SUSY-split messenger masses arise. We calculate these masses by three complementary methods. Additionally, we compute the one-loop corrections to the masses. We consider this model both with and without a Fayet-Iliopoulos term for the hidden sector U(1). Finally, we write down a simple model of Minimal Gauge Mediation in which the only scale is dynamically generated.
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| 61. |
- Enberg, R., et al.
(författare)
-
LHC and dark matter signals of improved naturalness
- 2007
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; 0711, s. 014-
-
Tidskriftsartikel (refereegranskat)
|
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| 62. |
- Engquist, Johan, et al.
(författare)
-
Yang-Mills duals for semiclassical strings on AdS5 × S5
- 2003
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; 0311, s. 063-
-
Tidskriftsartikel (refereegranskat)abstract
- We consider a semiclassical multiwrapped circular string pulsating on S5, whose center of mass has angular momentum J on an S3 subspace. Using the AdS/CFT correspondence we argue that the one-loop anomalous dimension of the dual operator is a simple rational function of J/L, where J is the R-charge and L is the bare dimension of the operator. We then reproduce this result directly from a super Yang-Mills computation, where we make use of the integrability of the one-loop system to set up an integral equation that we solve. We then verify the results of Frolov and Tseytlin for circular rotating strings with R-charge assignment (J',J',J). In this case we solve for an integral equation found in the O(−1) matrix model when J'<J and the O(+1) matrix model if J'>J. The latter region starts at J' = L/2 and continues down, but an apparent critical point is reached at J' = 4J. We argue that the critical point is just an artifact of the Bethe ansatz and that the conserved charges of the underlying integrable model are analytic for all J' and that the results from the O(−1) model continue onto the results of the O(+1) model.
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| 63. |
- Eriksson, David, et al.
(författare)
-
Charged Higgs bosons in minimal supersymmetry : updated constraints and experimental prospects
- 2008
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; 11:035
-
Tidskriftsartikel (refereegranskat)abstract
- We discuss the phenomenology of charged Higgs bosons in the MSSM with minimal flavor violation. In addition to the constrained MSSM (CMSSM) with universal soft supersymmetry breaking mass parameters at the GUT scale, we explore non-universal Higgs mass models (NUHM) where this universality condition is relaxed. To identify the allowed parameter space regions, we apply constraints from direct searches, low energy observables, and cosmology. We find that values of the charged Higgs mass as low as mH+ 135 GeV can be accommodated in the NUHM models, but that several flavor physics observables disfavor large H+ contributions, associated with high tan β, quite independently of MSSM scenario. We confront the constrained scenarios with the discovery potentials reported by ATLAS and CMS, and find that the current exclusion by indirect constraints is similar to the expected LHC discovery reach with 30 fb−1 of data. Finally, we evaluate the sensitivity of the presented discovery potential to the choice of MSSM benchmark scenario. This sensitivity is found to be higher in the case of a light (mH+ < mt) charged Higgs.
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| 64. |
- Freyhult, Lisa
(författare)
-
Bethe ansatz and fluctuations in SU(3) Yang-Mills operators
- 2004
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :06, s. 010-
-
Tidskriftsartikel (refereegranskat)abstract
- We consider the scalar operators corresponding to semiclassical string states in AdS5 × S5 with the three angular momenta in S5 non-trivial. The string states recieve quantum corrections and we study the corresponding process on the gauge theory side. The anomalous dimension of the scalar operators is computed using the Bethe ansatz and we find the correction that corresponds to the energy of the quantized string. We restrict for simplicity to the case where two of the angular momenta in S5 are equal.
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| 65. |
- Garbrecht, Björn, et al.
(författare)
-
Hybrid inflation exit through tunneling
- 2007
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :1, s. 033-
-
Tidskriftsartikel (refereegranskat)abstract
- For hybrid inflationary potentials, we derive the tunneling rate from field configurations along the flat direction towards the waterfall regime. This process competes with the classically rolling evolution of the scalar fields and needs to be strongly subdominant for phenomenologically viable models. Tunneling may exclude models with a mass scale below 10(12) GeV, but can be suppressed by small values of the coupling constants. We find that tunneling is negligible for those models, which do not require fine tuning in order to cancel radiative corrections, in particular for GUT-scale SUSY inflation. In contrast, electroweak scale hybrid inflation is not viable, unless the inflaton-waterfall field coupling is smaller than approximately 10(-11).
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| 66. |
- Giangreco Marotta Puletti, Valentina, 1980-
(författare)
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Operator product expansion for pure spinor superstring on AdS5 x S5
- 2006
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :10, s. 057-
-
Tidskriftsartikel (refereegranskat)abstract
- The tree-level operator product expansion coefficients of the matter currents are calculated in the pure spinor formalism for type IIB superstring in the AdS5 × S5 background.
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| 67. |
- Gran, Ulf, 1973, et al.
(författare)
-
Three-dimensional N=8 superconformal gravity and its coupling to BLG M2-branes
- 2009
-
Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479 .- 1126-6708. ; 2009:3
-
Tidskriftsartikel (refereegranskat)abstract
- This paper is concerned with the problem of coupling the N=8 superconformal Bagger-Lambert-Gustavsson (BLG) theory to N=8 conformal supergravity in three dimensions. We start by constructing the on-shell N=8 conformal supergravity in three dimensions consisting of a Chern-Simons type term for each of the gauge fields: the spin connection, the SO(8) R-symmetry gauge field and the spin 3/2 Rarita-Schwinger (gravitino) field. We then describe how to couple this minimally to the BLG theory. The final theory should have the same physical content, i.e., degrees of freedom, as the ordinary BLG theory. We discuss briefly the properties of this "topologically gauged" BLG theory and why this theory may be useful.
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| 68. |
- Hoppe, Jens, et al.
(författare)
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New BPS configurations of BMN matrix theory
- 2008
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :6
-
Tidskriftsartikel (refereegranskat)abstract
- We explore the 1/2 BPS configurations in BMN matrix theory with SO(3) angular momentum of SO(3) x SO(6) symmetry. The fluctuation analysis of the BPS configurations near the abelian solutions and also the fuzzy two sphere vacua reveals how nonabelian BPS configurations emerge. Especially the irreducible nonabelian configurations seem to have the maximal angular momentum of order N-3 ,beyond which they collapse to abelian ones. We also find some new BPS configurations explicitly.
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| 69. |
- Howe, Paul, et al.
(författare)
-
On the covariance of the Dirac-Born-Infeld-Myers action
- 2007
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :2, s. 70-
-
Tidskriftsartikel (refereegranskat)abstract
- A covariant version of the non- abelian Dirac-Born-Infeld-Myers action is presented. The non-abelian degrees of freedom are incorporated by adjoining to the (bosonic) worldvolume of the brane a number of anticommuting fermionic directions corresponding to boundary fermions in the string picture. The proposed action treats these variables as classical but can be given a matrix interpretation if a suitable quantisation prescription is adopted. After gauge-fixing and quantisation of the fermions, the action is shown to be in agreement with the Myers action derived from T-duality. It is also shown that the requirement of covariance in the above sense leads to a modified WZ term which also agrees with the one proposed by Myers.
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| 70. |
- Howe, P. S., et al.
(författare)
-
Kappa-symmetry for coincident D-branes
- 2007
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; 09
-
Tidskriftsartikel (refereegranskat)abstract
- A kappa-symmetric action for coincident D-branes is presented. It is valid in the approximation that the additional fermionic variables, used to incorporate the non-abelian degrees of freedom, are treated classically. The action is written as a Bernstein-Leites integral on the supermanifold obtained from the bosonic worldvolume by adjoining the extra fermions. The integrand is a very simple extension of the usual Green-Schwarz action for a single brane; all symmetries, except for kappa, are manifest, and the proof of kappa-symmetry is very similar to the abelian case.
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| 71. |
- Hull, C. M., et al.
(författare)
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Euclidean supersymmetry, twisting and topological sigma models
- 2008
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :6, s. 031-
-
Tidskriftsartikel (refereegranskat)abstract
- We discuss two dimensional N-extended supersymmetry in Euclidean signature and its R-symmetry. For N = 2, the R-symmetry is SO(2) x SO(1, 1), so that only an A-twist is possible. To formulate a B-twist, or to construct Euclidean N = 2 models with H-flux so that the target geometry is generalised Kahler, it is necessary to work with a complexification of the sigma models. These issues are related to the obstructions to the existence of non-trivial twisted chiral superfields in Euclidean superspace.
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| 72. |
- Hull, C. M., et al.
(författare)
-
Geometry of the N=2 supersymmetric sigma model with Euclidean worldsheet
- 2009
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :7, s. 078-
-
Tidskriftsartikel (refereegranskat)abstract
- We investigate the target space geometry of supersymmetric sigma models in two dimensions with Euclidean signature, and the conditions for N = 2 supersymmetry. For a real action, the geometry for the N = 2 model is not the generalized Kahler geometry that arises for Lorentzian signature, but is an interesting modification of this which is not a complex geometry.
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| 73. |
- Hull, C. M., et al.
(författare)
-
Topological sigma models with H-flux
- 2008
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :9, s. 057-
-
Tidskriftsartikel (refereegranskat)abstract
- We investigate the topological theory obtained by twisting the N = (2, 2) supersymmetric nonlinear sigma model with target a bihermitian space with torsion. For the special case in which the two complex structures commute, we show that the action is a Q-exact term plus a quasi-topological term. The quasi-topological term is locally given by a closed two-form which corresponds to a flat gerbe-connection and generalises the usual topological term of the A-model. Exponentiating it gives a Wilson surface, which can be regarded as a generalization of a Wilson line. This makes the quantum theory globally well-defined.
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| 74. |
- Kazakov, V. A., et al.
(författare)
-
Classical/quantum integrability in AdS/CFT
- 2004
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; 05, s. 024-
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Tidskriftsartikel (refereegranskat)abstract
- We discuss the AdS/CFT duality from the perspective of integrable systems and establish a direct relationship between the dimension of single trace local operators composed of two types of scalar fields in = 4 super Yang-Mills and the energy of their dual semiclassical string states in AdS5 × S5. The anomalous dimensions can be computed using a set of Bethe equations, which for ``long'' operators reduces to a Riemann-Hilbert problem. We develop a unified approach to the long wavelength Bethe equations, the classical ferromagnet and the classical string solutions in the SU(2) sector and present a general solution, governed by complex curves endowed with meromorphic differentials with integer periods. Using this solution we compute the anomalous dimensions of these long operators up to two loops and demonstrate that they agree with string-theory predictions.
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| 75. |
- Kleinschmidt, Axel, et al.
(författare)
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K(E9) from K(E10)
- 2007
-
Ingår i: Journal of High Energy Physics (JHEP). - : IOP Publishing. - 1126-6708 .- 1029-8479. ; :6
-
Tidskriftsartikel (refereegranskat)abstract
- We analyse the M-theoretic generalisation of the tangent space structure group after reduction of the D = 11 supergravity theory to two space-time dimensions in the context of hidden Kac-Moody symmetries. The action of the resulting infinite-dimensional 'R symmetry' group K(E-9) on certain unfaithful, finite-dimensional spinor representations inherited from K(E-10) is studied. We explain in detail how these representations are related to certain finite codimension ideals within K(E-9), which we exhibit explicitly, and how the known, as well as new finite-dimensional 'generalised holonomy groups' arise as quotients of K(E-9) by these ideals. In terms of the loop algebra realisations of E-9 and K(E-9) on the fields of maximal supergravity in two space-time dimensions, these quotients are shown to correspond to (generalised) evaluation maps, in agreement with previous results of [1]. The outstanding question is now whether the related unfaithful representations of K(E-10) can be understood in a similar way.
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| 76. |
- Klose, Thomas, et al.
(författare)
-
Reduced sigma-model on AdS(5) x S-5 : one-loop scattering amplitudes
- 2007
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :2, s. 071-
-
Tidskriftsartikel (refereegranskat)abstract
- We compute the one-loop S-matrix in the reduced sigma-model which describes AdS5 × S5 string theory in the near-flat-space limit. The result agrees with the corresponding limit of the S-matrix in the full sigma-model, which demonstrates the consistency of the reduction at the quantum level.
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| 77. |
- Klose, Thomas, et al.
(författare)
-
Worldsheet scattering in AdS(5) x S-5
- 2007
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :3, s. 094-
-
Tidskriftsartikel (refereegranskat)abstract
- We calculate the S-matrix in the gauge-fixed sigma-model on AdS(5) x S-5 to the leading order in perturbation theory, and analyze how supersymmetry is realized on the scattering states. A mild nonlocality of the supercharges implies that their action on multi-particle states does not follow the Leibniz rule, which is replaced by a nontrivial coproduct. The plane wave symmetry algebra is thus naturally enhanced to a Hopf algebra. This structure mirrors that of the large't Hooft coupling expansion of the S-matrix for the spin chain in the dual super-Yang-Mills theory.
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| 78. |
- Kuzenko, S. M., et al.
(författare)
-
4D N=2 supergravity and projective superspace
- 2008
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :9, s. 051-
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents a projective superspace formulation for 4D N = 2 matter-coupled supergravity. We first describe a variant superspace realization for the N = 2 Weyl multiplet. It differs from that proposed by Howe in 1982 by the choice of the structure group SO(3, 1) x SU(2) versus SO(3, 1) x U( 2)), which implies that the super-Weyl transformations are generated by a covariantly chiral parameter instead of a real unconstrained one. We introduce various off-shell supermultiplets which are curved superspace analogues of the superconformal projective multiplets in global supersymmetry and which describe matter fields coupled to supergravity. A manifestly locally supersymmetric and super-Weyl invariant action principle is given. Off-shell locally supersymmetric nonlinear sigma models are presented in this new superspace.
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| 79. |
- Kuzenko, Sergei M., et al.
(författare)
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New extended superconformal sigma models and quaternion Kahler manifolds
- 2009
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :9, s. 119-
-
Tidskriftsartikel (refereegranskat)abstract
- Quaternion Kahler manifolds are known to be the target spaces for matter hypermultiplets coupled to N = 2 supergravity. It is also known that there is a one-to-one correspondence between 4n-dimensional quaternion Kahler manifolds and those 4(n + 1)dimensional hyperkahler spaces which are the target spaces for rigid superconformal hypermultiplets (such spaces are called hyperkahler cones). In this paper we present a projective-superspace construction to generate a hyperkahler cone M-H(4(n + 1)) of dimension 4(n + 1) from a 2n-dimensional real analytic Kahler-Hodge manifold M-K(2n). The latter emerges as a maximal Kahler submanifold of the 4n-dimensional quaternion Kahler space M-Q(4n) such that its Swann bundle coincides with M-H(4)(n + 1). Our approach should be useful for the explicit construction of new quaternion Kahler metrics. The results obtained are also of interest, e. g., in the context of supergravity reduction N = 2 -> N = 1, or alternatively from the point of view of embedding N = 1 matter-coupled supergravity into an N = 2 theory.
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| 80. |
- Kuzenko, S. M., et al.
(författare)
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On conformal supergravity and projective superspace
- 2009
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :8, s. 023-
-
Tidskriftsartikel (refereegranskat)abstract
- The projective superspace formulation for four-dimensional N = 2 matter-coupled supergravity presented in arXiv:0805.4683 makes use of the variant superspace realization for the N = 2 Weyl multiplet in which the structure group is SL(2, C) x SU(2) and the super-Weyl transformations are generated by a covariantly chiral parameter. An extension to Howe's realization of N = 2 conformal supergravity in which the tangent space group is SL(2, C) x U(2) and the super-Weyl transformations are generated by a real unconstrained parameter was briefly sketched. Here we give the explicit details of the extension.
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| 81. |
- Lafaye, Remi, et al.
(författare)
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Measuring the Higgs Sector
- 2009
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :8, s. 009-
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Tidskriftsartikel (refereegranskat)abstract
- If we find a light Higgs boson at the LHC, there should be many observable channels which we can exploit to measure the relevant parameters in the Higgs sector. We use the SFitter framework to map these measurements on the parameter space of a general weak-scale effective theory with a light Higgs state of mass 120GeV. Our analysis benefits from the parameter determination tools and the error treatment used in new-physics searches, to study individual parameters and their error bars as well as parameter correlations.
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| 82. |
- Langmann, Edwin, et al.
(författare)
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Exact solution of quantum field theory on noncommutative phase spaces
- 2004
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :1, s. 017-
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Tidskriftsartikel (refereegranskat)abstract
- We present the exact solution of a scalar field theory defined with noncommuting position and momentum variables. The model describes charged particles in a uniform magnetic field and with an interaction defined by the Groenewold-Moyal star-product. Explicit results are presented for all Green's functions in arbitrary even spacetime dimensionality. Various scaling limits of the field theory are analysed non-perturbatively and the renormalizability of each limit examined. A supersymmetric extension of the field theory is also constructed in which the supersymmetry transformations are parametrized by differential operators in an in finite-dimensional noncommutative algebra.
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| 83. |
- Lindström, Ulf, et al.
(författare)
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Linearizing Generalized Kahler Geometry
- 2007
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :4, s. 061-
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Tidskriftsartikel (refereegranskat)abstract
- The geometry of the target space of an N = (2, 2) supersymmetry sigma-model carries a generalized Kähler structure. There always exists a real function, the generalized Kähler potential K, that encodes all the relevant local differential geometry data: the metric, the B-field, etc. Generically this data is given by nonlinear functions of the second derivatives of K. We show that, at least locally, the nonlinearity on any generalized Kähler manifold can be explained as arising from a quotient of a space without this nonlinearity.
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| 84. |
- Lindström, Ulf, et al.
(författare)
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New N = (2, 2) vector multiplets
- 2007
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :8, s. 008-
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Tidskriftsartikel (refereegranskat)abstract
- We introduce two new N = (2, 2) vector multiplets that couple naturally to generalized Kähler geometries. We describe their kinetic actions as well as their matter couplings both in N = (2, 2) and N = (1, 1) superspace.
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| 85. |
- Łukowski, Tomasz, et al.
(författare)
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Finite size giant magnons in the SU(2) × SU(2) sector of AdS4 × CP3
- 2008
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; 12, s. 073-
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Tidskriftsartikel (refereegranskat)abstract
- We use the algebraic curve and Lüscher's μ-term to calculate the leading order finite size corrections to the dispersion relation of giant magnons in the SU(2) × SU(2) sector of AdS4 × CP3. We consider a single magnon as well as one magnon in each SU(2). In addition the algebraic curve computation is generalized to give the leading order correction for an arbitrary multi-magnon state in the SU(2) × SU(2) sector.
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| 86. |
- Mahmoudi, Farvah
(författare)
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New constraints on supersymmetric models from b --> s gamma
- 2007
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; 12, s. 026-
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- We provide an analysis of the parameter space of several supersymmetry breaking scenarios such as the minimal supergravity (mSUGRA) model and the non universal Higgs mass (NUHM) framework, as well as the Anomaly Mediated Supersymmetry Breaking (AMSB) and the Gauge Mediated Supersymmetry Breaking (GMSB) models, in the light of a novel observable in b → sγ transitions, i.e. the isospin symmetry breaking in the exclusive B → K*γ decays. We find that in many cases, this observable provides severe restrictions on the allowed parameter space regions for the mentioned models. Moreover, we provide a few examples of investigations of the physical masses of supersymmetric particles and search for the excluded values. The constraints from the branching ratio associated to b → sγ are also presented here for all the examined parameter space regions. A comparison with Bs → μ+μ− branching ratio has also been performed.
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| 87. |
- Minahan, Joseph A., et al.
(författare)
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The Bethe ansatz for superconformal Chern-Simons
- 2008
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :9, s. 040-
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Tidskriftsartikel (refereegranskat)abstract
- We study the anomalous dimensions for scalar operators for a three-dimensional Chern-Simons theory recently proposed in arXiv:0806.1218. We show that the mixing matrix at two-loop order is that for an integrable Hamiltonian of an SU(4) spin chain with sites alternating between the fundamental and the anti-fundamental representations. We find a set of Bethe equations from which the anomalous dimensions can be determined and give a proposal for the Bethe equations to the full superconformal group of OSp(2,2 vertical bar 6).
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| 88. |
- Minahan, Joseph A., et al.
(författare)
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Two loop integrability for Chern-Simons theories with N=6 supersymmetry
- 2009
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :3, s. 057-
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Tidskriftsartikel (refereegranskat)abstract
- We consider two-loop anomalous dimensions for fermionic operators in the ABJM model and the ABJ model. We find the appropriate Hamiltonian and show that it is consistent with a previously predicted Bethe ansatz for the ABJM model. The difference between the ABJ and ABJM models is invisible at the two-loop level due to cancelation of parity violating diagrams. We then construct a Hamiltonian for the full two-loop OSp(6|4) spin chain by first constructing the Hamiltonian for an SL(2|1) subgroup, and then lifting to OSp(6|4). We show that this Hamiltonian is consistent with the Hamiltonian found for the fermionic operators.
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| 89. |
- Minahan, Joseph A.
(författare)
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Zero modes for the giant magnon
- 2007
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :2, s. 048-
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Tidskriftsartikel (refereegranskat)abstract
- We explicitly construct the eight fermion zero mode solutions for the Hofman-Maldacena giant magnon. The solutions are naturally gauge fixed under the κ-symmetry. Substituting the solutions back into the Lagrangian leads to a simple expression that can be quantized directly. We also show how to construct the SU(2|2) × SU(2|2) superalgebra from these zero modes. For completeness we also find the four bosonic zero mode solutions.
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| 90. |
- Moretti, M., et al.
(författare)
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Vector-Boson Production of Light Higgs Pairs in 2-Higgs Doublet Models
- 2007
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- At the Large Hadron Collider, we prove the feasibility to detect pair production of the lightest CP-even Higgs boson h of Type II 2-Higgs Doublet Models through qq(') -> qq(')hh (vector-boson fusion). We also show that, through the hh -> 4b decay channel in presence of heavy-flavour tagging, further exploiting forward/backward jet sampling, one has direct access to the lambda Hhh triple Higgs coupling - which constrains the form of the Higgs potential.
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| 91. |
- Persson, Jonas
(författare)
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T-duality and generalized complex geometry
- 2007
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :3, s. 025-
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Tidskriftsartikel (refereegranskat)abstract
- We find the explicit T-duality transformation in the phase space formulation of the N = (1,1) sigma model. We also show that the T-duality transformation is a symplectomorphism and it is an element of O(d,d). Further, we find the explicit T-duality transformation of a generalized complex structure in this model. We also show that the extended supersymmetry of the sigma model is preserved under the T-duality.
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| 92. |
- Poludniowski, Gavin, et al.
(författare)
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Vector Meson Photoproduction from the BFKL Equation II: Phenomenology
- 2003
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; 12, s. 002-
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Tidskriftsartikel (refereegranskat)abstract
- Diffractive vector meson photoproduction accompanied by proton dissociation is studied for large momentum transfer. The process is described by the non-forward BFKL equation which we use to compare to data collected at the HERA collider.
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| 93. |
- Qiu, Jian, et al.
(författare)
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On the AKSZ formulation of the Rozansky-Witten theory and beyond
- 2009
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :9, s. 024-
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Tidskriftsartikel (refereegranskat)abstract
- Using the AKSZ formalism, we construct the Batalin-Vilkovisky master action for the Rozansky-Witten model, which can be defined for any complex manifold with a closed (2,0)-form. We also construct the holomorphic version of Rozansky-Witten theory defined over Calabi-Yau 3-fold.
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| 94. |
- Schäfer-Nameki, Sakura, et al.
(författare)
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How accurate is the quantum string Bethe ansatz?
- 2006
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :12, s. 020-
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Tidskriftsartikel (refereegranskat)abstract
- We compare solutions of the quantum string Bethe equations with explicit one-loop calculations in the sigma-model on AdS(5) x S-5. The Bethe ansatz exactly reproduces the spectrum of infinitely long strings. When the length is finite, we find that deviations from the exact answer arise which are exponentially small in the string length.
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| 95. |
- Zarembo, Konstantin
(författare)
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Quantum giant magnons
- 2008
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Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :5, s. 47-
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Tidskriftsartikel (refereegranskat)abstract
- The giant magnons are classical solitons of the O(N) sigma-model, which play an important role in the AdS/CFT correspondence. We study quantum giant magnons first at large N and then exactly using Bethe Ansatz, where giant magnons can be interpreted as holes in the Fermi sea. We also identify a solvable limit of Bethe Ansatz in which it describes a weakly-interacting Bose gas at zero temperature. The examples include the O(N) model at large-N, weakly interacting non-linear Schrodinger model, and nearly isotropic XXZ spin chain in the magnetic field.
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| 96. |
- Zarembo, K
(författare)
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Worldsheet spectrum in AdS(4)/CFT3 correspondence
- 2009
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :4, s. 135-
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Tidskriftsartikel (refereegranskat)abstract
- The AdS(4)/CFT3 duality is a new example of an integrable and exactly solvable AdS/CFT system. There is, however, a puzzling mismatch between the number of degrees of freedom used in the exact solution (4(B) + 4(F) scattering states) and 8(B) + 8(F) transverse oscillation modes of critical superstring theory. We off er a resolution of this puzzle by arguing that half of the string modes dissolve in the continuum of two-particle states once alpha' corrections are taken into account. We also check that the conjectured exact S-matrix of AdS(4)/CFT3 [1] agrees with the tree-level worldsheet calculation.
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| 97. |
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| 98. |
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| 99. |
- Aaboud, M., et al.
(författare)
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Measurements of b-jet tagging efficiency with the ATLAS detector using tt¯" role="presentation">tt¯ events at s=13" role="presentation">s√=13 TeV
- 2018
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Ingår i: Journal of High Energy Physics (JHEP). - : SPRINGER. - 1126-6708 .- 1029-8479. ; :8
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Tidskriftsartikel (refereegranskat)abstract
- The efficiency to identify jets containing b-hadrons (b-jets) is measured using a high purity sample of dileptonic top quark-antiquark pairs (t (t) over bar) selected from the 36.1 fb(-1) of data collected by the ATLAS detector in 2015 and 2016 from proton-proton collisions produced by the Large Hadron Collider at a centre-of-mass energy root s = 13 TeV. Two methods are used to extract the efficiency from t (t) over bar events, a combinatorial likelihood approach and a tag-and-probe method. A boosted decision tree, not using b-tagging information, is used to select events in which two b-jets are present, which reduces the dominant uncertainty in the modelling of the flavour of the jets. The efficiency is extracted for jets in a transverse momentum range from 20 to 300 GeV, with data-to-simulation scale factors calculated by comparing the efficiency measured using collision data to that predicted by the simulation. The two methods give compatible results, and achieve a similar level of precision, measuring data-to-simulation scale factors close to unity with uncertainties ranging from 2% to 12% depending on the jet transverse momentum.
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| 100. |
- Aaboud, M, et al.
(författare)
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Measurements of top-quark pair differential cross-sections in the lepton+jets channel in pp collisions at √s=13 TeV using the ATLAS detector
- 2017
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Ingår i: Journal of High Energy Physics. - 1029-8479 .- 1126-6708. ; 2017:11
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Tidskriftsartikel (refereegranskat)abstract
- Measurements of differential cross-sections of top-quark pair production in fiducial phase-spaces are presented as a function of top-quark and tt¯ system kinematic observables in proton-proton collisions at a centre-of-mass energy of s=13 TeV. The data set corresponds to an integrated luminosity of 3.2 fb−1, recorded in 2015 with the ATLAS detector at the CERN Large Hadron Collider. Events with exactly one electron or muon and at least two jets in the final state are used for the measurement. Two separate selections are applied that each focus on different top-quark momentum regions, referred to as resolved and boosted topologies of the tt¯ final state. The measured spectra are corrected for detector effects and are compared to several Monte Carlo simulations by means of calculated χ2 and p-values. © 2017, The Author(s).
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