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1.	Bundzik, Daniel (författare) Star product and the general Leigh-Strassler deformation 2007 Ingår i: Journal of High Energy Physics (JHEP). - : SISSA. - 1126-6708 .- 1029-8479. ; :04 Tidskriftsartikel (refereegranskat)abstract We extend the definition of the star product introduced by Lunin and Maldacena to study marginal deformations of = 4 SYM. The essential difference from the latter is that instead of considering U(1) × U(1) non-R-symmetry, with charges in a corresponding diagonal matrix, we consider two 3-symmetries followed by an SU(3) transformation, with resulting off-diagonal elements. From this procedure we obtain a more general Leigh–Strassler deformation, including cubic terms with the same index, for specific values of the coupling constants. We argue that the conformal property of = 4 SYM is preserved, in both β- (one-parameter) and γi-deformed (three-parameters) theories, since the deformation for each amplitude can be extracted in a prefactor. We also conclude that the obtained amplitudes should follow the iterative structure of MHV amplitudes found by Bern, Dixon and Smirnov.
2.	Månsson, Teresia, 1974- (författare) The Liegh-Strassler deformation and the quest for integrability 2007 Ingår i: Journal of High Energy Physics (JHEP). - : Institute of Physics Publishing (IOPP). - 1126-6708 .- 1029-8479. Tidskriftsartikel (refereegranskat)abstract In this paper we study the one-loop dilatation operator of the full scalar field sector of Leigh-Strassler deformed =4 SYM theory. In particular we map it onto a spin chain and find the parameter values for which the Reshetikhin integrability criteria are fulfilled. Some years ago Roiban found an integrable subsector, consisting of two holomorphic scalar fields, corresponding to the XXZ model. He was pondering about the existence of a subsector which would form generalisation of that model to an integrable q(3) model. Later Berenstein and Cherkis added one more holomorphic field and showed that the subsector obtained this way cannot be integrable except for the case when q = eiβ, β. In this work we show if we add an anti-holomorphic field to the two holomorphic ones, we get indeed an integrable q(3) subsector. We find it plausible that a direct generalisation to a q(2\|3) one-loop sector will exist, and possibly beyond one-loop.
3.	Bundzik, Daniel, et al. (författare) The general Leigh-Strassler deformation and integrability 2006 Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479 .- 1126-6708. ; :1 Tidskriftsartikel (refereegranskat)abstract The success of the identification of the planar dilatation operator of N = 4 SYM with an integrable spin chain Hamiltonian has raised the question if this also is valid for a deformed theory. Several deformations of SYM have recently been under investigation in this context. In this work we consider the general Leigh-Strassler deformation. For the generic case the S-matrix techniques cannot be used to prove integrability. Instead we use R-matrix techniques to study integrability. Some new integrable points in the parameter space are found.
4.	Argurio, Riccardo, 1972, et al. (författare) Massless fermionic bound states and the gauge/gravity correspondence 2006 Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479 .- 1126-6708. ; 03:2006, s. 043- Tidskriftsartikel (refereegranskat)abstract We study the equations of motion of fermions in type IIB supergravity in the context of the gauge/gravity correspondence. The main motivation is the search for normalizable fermionic zero modes in such backgrounds, to be interpreted as composite massless fermions in the dual theory. We specialize to backgrounds characterized by a constant dilaton and a self-dual three-form. In the specific case of the Klebanov-Strassler solution we construct explicitly the fermionic superpartner of the Goldstone mode associated with the broken baryonic symmetry. The fermionic equations could also be used to search for goldstinos in theories that break supersymmetry dynamically.
5.	Henningson, Måns, 1964, et al. (författare) Zero-energy bound states of N=4 SYM on T^3: S-duality and the mapping class group 2008 Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479 .- 1126-6708. ; 0804:4, s. 066- Tidskriftsartikel (refereegranskat)abstract We continue our studies of the low-energy spectrum of N = 4 super-Yang-Mills theory on a spatial three-torus. In two previous papers, we computed the spectrum of normalizable zero-energy states for all choices of gauge group and all values of the electric and magnetic 't Hooft fluxes, and checked its invariance under the SL2(Z) S-duality group. In this paper, we refine the analysis by also decomposing the space of bound states into irreducible unitary representations of the SL3(Z) mapping class group of the three-torus. We perform a detailed study of the S-dual pairs of theories with gauge groups Spin(2n+1) and Sp(2n). The predictions of S-duality (which commutes with the mapping class group) are fulfilled as expected, but the proof requires some surprisingly intricate combinatorial infinite product identities.
6.	Akhmedov, Evgeny K., et al. (författare) Series expansions for three-flavor neutrino oscillation probabilities in matter 2004 Ingår i: Journal of High Energy Physics (JHEP). - : IOP Publishing. - 1126-6708 .- 1029-8479. ; 2004:04, s. 078- Tidskriftsartikel (refereegranskat)abstract We present a number of complete sets of series expansion formulas for neutrino oscillation probabilities in matter of constant density for three flavors. In particular, we study expansions in the mass hierarchy parameter alpha = Deltam(21)(2)/Deltam(31)(2) and mixing parameter s(13) = sin theta(13) up to second order and expansions only in alpha and only in s(13) up to first order. For each type of expansion we also present the corresponding formulas for neutrino oscillations in vacuum. We perform a detailed analysis of the accuracy of the different sets of series expansion formulas and investigate which type of expansion is most accurate in different regions of the parameter space spanned by the neutrino energy E, the baseline length L, and the expansion parameters alpha and s(13). We also present the formulas for series expansions in alpha and in s(13) up to first order for the case of arbitrary matter density profiles. Furthermore, it is shown that in general all the 18 neutrino and antineutrino oscillation probabilities can be expressed through just two independent probabilities.
7.	Blennow, Mattias, et al. (författare) Damping signatures in future neutrino oscillation experiments 2005 Ingår i: Journal of High Energy Physics (JHEP). - : IOP Publishing. - 1126-6708 .- 1029-8479. ; 2005:06, s. 049- Tidskriftsartikel (refereegranskat)abstract We discuss the phenomenology of damping signatures in the neutrino oscillation probabilities, where either the oscillating terms or the probabilities can be damped. This approach is a possibility for tests of damping effects in future neutrino oscillation experiments, where we mainly focus on reactor and long-baseline experiments. We extensively motivate different damping signatures due to small corrections by neutrino decoherence, neutrino decay, oscillations into sterile neutrinos, or other mechanisms, and classify these signatures according to their energy ( spectral) dependencies. We demonstrate, at the example of short baseline reactor experiments, that damping can severely alter the interpretation of results, e. g., it could fake a value of sin(2)(2 theta(13)) smaller than the one provided by Nature. In addition, we demonstrate how a neutrino factory could constrain different damping models with emphasis on how these different models could be distinguished, i.e., how easily the actual type of effect could be identified. We find that the damping models cluster in different categories, which can be much better distinguished from each other than models within the same cluster.
8.	Meloni, Davide, et al. (författare) Exact and approximate formulas for neutrino mixing and oscillations with non-standard interactions 2009 Ingår i: Journal of High Energy Physics (JHEP). - : IOP Publishing. - 1126-6708 .- 1029-8479. ; 2009:04, s. 033- Tidskriftsartikel (refereegranskat)abstract We present, both exactly and approximately, a complete set of mappings between the vacuum (or fundamental) leptonic mixing parameters and the effective ones in matter with non-standard neutrino interaction (NSI) effects included. Within the three-flavor neutrino framework and a constant matter density profile, a full set of sum rules is established, which enables us to reconstruct the moduli of the effective leptonic mixing matrix elements, in terms of the vacuum mixing parameters in order to reproduce the neutrino oscillation probabilities for future long-baseline experiments. Very compact, but quite accurate, approximate mappings are obtained based on series expansions in the neutrino mass hierarchy parameter eta equivalent to Delta m(21)(2)/Delta m(31)(2), the vacuum leptonic mixing parameter s(13) equivalent to sin theta(13), and the NSI parameters epsilon(alpha beta). A detailed numerical analysis about how the NSIs affect the smallest leptonic mixing angle theta(13), the deviation of the leptonic mixing angle theta(23) from its maximal mixing value, and the transition probabilities useful for future experiments are performed using our analytical results.
9.	Agarwal, Abhishek, et al. (författare) Higher charges in dynamical spin chains for SYM theory 2005 Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479 .- 1126-6708. ; :10, s. 1291-1302 Tidskriftsartikel (refereegranskat)abstract We construct, to the first two non-trivial orders, the next conserved charge in the su(2\|3) sector of N=4 Super Yang-Mills theory. This represents a test of integrability in a sector where the interactions change the number of sites of the chain. The expression for the charge is completely determined by the algebra and can be written in a diagrammatic form in terms of the interactions already present in the Hamiltonian. It appears likely that this diagrammatic expression remains valid in the full theory and can be generalized to higher loops and higher charges thus helping in establishing complete integrability for these dynamical chains.
10.	Ananth, S., et al. (författare) Eleven-dimensional supergravity in light-cone superspace 2005 Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479 .- 1126-6708. ; 5:5, s. 56-71 Tidskriftsartikel (refereegranskat)abstract We show that Supergravity in eleven dimensions can be described in terms of a constrained superfield on the light-cone, without the use of auxiliary fields. We build its action to first order in the gravitational coupling constant \kappa, by "oxidizing" (N=8,d=4) Supergravity. This is simply achieved, as for N=4 Yang-Mills, by extending the transverse derivatives into superspace. The eleven-dimensional SuperPoincare algebra is constructed and a fourth order interaction is conjectured.
11.	Bachas, Constantin, et al. (författare) Nahm's equations, {$\scr N=1^$} domain walls, and {D}-strings in {${\rm AdS}_5\times S_5$} 2001 Ingår i:* Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :7, s. Paper 41,28- Tidskriftsartikel (refereegranskat)abstract We consider the following two problems: classical domain walls in the = 1* mass deformation of the maximally supersymmetric Yang Mills theory, and D-strings as external magnetic sources in the context of the AdS/CFT correspondence. We show that they are both described by Nahm's equations with unconventional boundary conditions, and analyze the relevant moduli space of solutions. We argue that general `fuzzy sphere' configurations of D-strings in AdS5 correspond to Wilson-'t Hooft lines in higher representations of the dual SU(n) gauge theory.
12.	Bao, Ling, 1980, et al. (författare) A note on topological M5-branes and string-fivebrane duality 2008 Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479 .- 1126-6708. ; 2008:6, s. 11- Tidskriftsartikel (refereegranskat)abstract We derive the stability conditions for the M5-brane in topological M-theory using k-symmetry. The non-linearly self-dual 3-form on the world-volume is necessarily non-vanishing, as is the case also for the 2-form field strengths on coisotropic branes in topological string theory. It is demonstrated that the self-duality is consistent with the stability conditions, which are solved locally in terms of a tensor in the representation 6 of SU(3) subset of G(2). The double dimensional reduction of the M5-brane is the D4-brane, and its direct reduction is an NS5-brane. We show that the equation of motion for the 3-form on the NS5-brane wrapping a Calabi-Yau space is exactly the Kodaira-Spencer equation, providing support for a string-fivebrane duality in topological string theory.
13.	Brink, Lars, 1943, et al. (författare) E7(7) on the Light Cone 2008 Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479 .- 1126-6708. ; 2008:6 Tidskriftsartikel (refereegranskat)abstract We use the Cremmer-Julia E-7(7) non-linear symmetry of N = 8 Supergravity to derive its order k(2) on-shell Hamiltonian in terms of one chiral light-cone superfield. By requiring that E-7(7) commute with the super-Poincare group, we deduce to lowest non-trivial order in k, the light cone E-7(7) transformations of all fields of the theory, including the gravition. We then derive the dynamical supersymmetry transformation to order k(2), and express the Hamiltonian as a quadratic form in the chiral superfield.
14.	Brink, Lars, 1943, et al. (författare) E8(8) in Light Cone Superspace 2008 Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479 .- 1126-6708. ; 2008:7 Tidskriftsartikel (refereegranskat)abstract We derive the non-linear action of E-8(8) on the constrained chiral superfield in the light-cone superspace with eight complex Grassmann variables. We construct (to lowest order in the coupling) the sixteen dynamical supersymmetries which generate a Hamiltonian with E-8(8) invariance in three space-time dimensions, and show that it has only interactions with even powers of the coupling constant.
15.	Chialva, Diego, et al. (författare) Deforming, revolving and resolving : New paths in the string theory landscape 2008 Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; 02 Tidskriftsartikel (refereegranskat)abstract In this paper we investigate the properties of series of vacua in the string theory landscape. In particular, we study minima to the flux potential in type IIB compactifications on the mirror quintic. Using geometric transitions, we embed its one-dimensional complex structure moduli space in that of another Calabi-Yau with h1,1 = 86 and h2,1 = 2. We then show how to construct infinite series of continuously connected minima to the mirror quintic potential by moving into this larger moduli space, applying its monodromies, and moving back. We provide an example of such series, and discuss their implications for the string theory landscape
16.	Enberg, Rikard, et al. (författare) Vector Meson Photoproduction from the BFKL Equation I: Theory 2003 Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; 9, s. 008- Tidskriftsartikel (refereegranskat)
17.	Eriksson, David, et al. (författare) New angles on top quark decay to a charged Higgs 2009 Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; 01:1, s. 024- Tidskriftsartikel (refereegranskat)abstract To properly discover a charged Higgs Boson (H±) requires its spin and couplings to be determined. We investigate how to utilize t spin correlations to analyze the H± couplings in the decay t → bH+ → bτ+ντ. Within the framework of a general Two-Higgs-Doublet Model, we obtain results on the spin analyzing coefficients for this decay and study in detail its spin phenomenology, focusing on the limits of large and small values for tan β. Using a Monte Carlo approach to simulate full hadron-level events, we evaluate systematically how the H± → τ±ντ decay mode can be used for spin analysis. The most promising observables are obtained from azimuthal angle correlations in the transverse rest frames of t(). This method is particularly useful for determining the coupling structure of H± in the large tan β limit, where differences from the SM are most significant.
18.	Ferretti, Gabriele, 1963, et al. (författare) Instantons and Toric Quiver Gauge Theories 2008 Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479 .- 1126-6708. ; 2008:7 Tidskriftsartikel (refereegranskat)abstract We show how to construct the general action coupling (multi)instantons to gauge theories arising from branes probing arbitrary toric singularities. We give a general set of rules for how to construct such an action given the knowledge of the superpotential for the gauge theory. The main idea is to obtain the action by higgsing a theory whose instanton dynamics is known, namely an orbifold of N=4 super Yang-Mills. We find that the couplings of the fermionic zero-modes with the holomorphic fields are dictated by the structure of the superpotential describing the toric singularity. We present explicit examples such as the Suspended Pinch Point, the Conifold and the first three del Pezzo's. We perform various checks on these results by further higgsing to smaller orbifolds and present some applications, including both gauge theory and stringy instantons.
19.	Ferretti, Gabriele, 1963, et al. (författare) Non-Perturbative Effects on a Fractional D3-Brane 2009 Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479 .- 1126-6708. ; 03:3, s. 040- Tidskriftsartikel (refereegranskat)abstract In this note we study the N = 1 abelian gauge theory on the world volume of a single fractional D3-brane. In the limit where gravitational interactions are not completely decoupled we find that a superpotential and a fermionic bilinear condensate are generated by a D-brane instanton effect. A related situation arises for an isolated cycle invariant under an orientifold projection, even in the absence of any gauge theory brane. Moreover, in presence of supersymmetry breaking background fluxes, such instanton configurations induce new couplings in the 4-dimensional effective action, including non-perturbative contributions to the cosmological constant and non-supersymmetric mass terms.
20.	Giangreco Marotta Puletti, Valentina (författare) Aspects of quantum integrability for pure spinor superstring in AdS5 × S5 2008 Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :09, s. 070- Tidskriftsartikel (refereegranskat)abstract We consider the monodromy matrix for the pure spinor IIB superstring on AdS5 × S5 at leading order at strong coupling, in particular its variation under an infinitesimal and continuous deformation of the contour. Such variation is equivalent to the insertion of a local operator. Demanding the BRST-closure for such an operator rules out its existence, implying that the monodromy matrix remains contour-independent at the first order in perturbation theory. Furthermore we explicitly compute the field strength corresponding to the flat connections up to leading order and directly check that it is free from logarithmic divergences. The absence of anomaly in the coordinate transformation of the monodromy matrix and the UV-finiteness of the curvature tensor finally imply the integrability of the pure spinor superstring at the first order.
21.	Gran, Ulf, 1973, et al. (författare) Geometry of all supersymmetric four-dimensional N=1 supergravity backgrounds 2008 Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479 .- 1126-6708. ; 06:6, s. 102- Tidskriftsartikel (refereegranskat)abstract We solve the Killing spinor equations of ${\cal N}=1$ supergravity, with four supercharges, coupled to any number of vector and scalar multiplets in all cases. We find that backgrounds with N=1 supersymmetry admit a null, integrable, Killing vector field. There are two classes of N=2 backgrounds. The spacetime in the first class admits a parallel null vector field and so it is a pp-wave. The spacetime of the other class admits three Killing vector fields, and a vector field that commutes with the three Killing directions. These backgrounds are of cohomogeneity one with homogenous sections either $\bR^{2,1}$ or $AdS_3$ and have an interpretation as domain walls. The N=3 backgrounds are locally maximally supersymmetric. There are N=3 backgrounds which arise as discrete identifications of maximally supersymmetric ones. The maximally supersymmetric backgrounds are locally isometric to either $\bR^{3,1}$ or $AdS_4$.
22.	Gran, Ulf, 1973, et al. (författare) Geometry of all supersymmetric type I backgrounds 2007 Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479 .- 1126-6708. ; :8, s. 074- Tidskriftsartikel (refereegranskat)abstract We find the geometry of all supersymmetric type I backgrounds by solving the gravitino and dilatino Killing spinor equations, using the spinorial geometry technique, in all cases. The solutions of the gravitino Killing spinor equation are characterized by their isotropy group in Spin(9,1), while the solutions of the dilatino Killing spinor equation are characterized by their isotropy group in the subgroup Sigma(P) of Spin(9,1) which preserves the space of parallel spinors P. Given a solution of the gravitino Killing spinor equation with L parallel spinors, L = 1,2,3,4,5,6,8, the dilatino Killing spinor equation allows for solutions with N supersymmetries for any 0
23.	Gran, Ulf, 1973, et al. (författare) IIB solutions with N>28 Killing spinors are maximally supersymmetric 2007 Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479 .- 1126-6708. ; 2007:12, s. 070- Tidskriftsartikel (refereegranskat)abstract We show that all IIB supergravity backgrounds which admit more than 28 Killing spinors are maximally supersymmetric. In particular, we find that for all N>28 backgrounds the supercovariant curvature vanishes, and that the quotients of maximally supersymmetric backgrounds either preserve all 32 or N
24.	Gran, Ulf, 1973, et al. (författare) On relating multiple M2 and D2-branes 2008 Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479 .- 1126-6708. ; 2008:10 Tidskriftsartikel (refereegranskat)abstract Due to the difficulties of finding superconformal Lagrangian theories for multiple M2-branes, we will in this paper instead focus on the field equations. By relaxing the requirement of a Lagrangian formulation we can explore the possibility of having structure constants fABCD satisfying the fundamental identity but which are not totally antisymmetric. We exemplify this discussion by making use of an explicit choice of a non-antisymmetric fABCD constructed from the Lie algebra structure constants fabc of an arbitrary gauge group. Although this choice of fABCD does not admit an obvious Lagrangian description, it does reproduce the correct SYM theory for a stack of N D2-branes to leading order in gYM−1 upon reduction and, moreover, it sheds new light on the centre of mass coordinates for multiple M2-branes.
25.	Grumiller, Daniel, 1973-, et al. (författare) Instability in cosmological topologically massive gravity at the chiral point 2008 Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :7, s. 134- Tidskriftsartikel (refereegranskat)abstract We consider cosmological topologically massive gravity at the chiral point with positive sign of the Einstein-Hilbert term. We demonstrate the presence of a negative energy bulk mode that grows linearly in time. Unless there are physical reasons to discard this mode, this theory is unstable. To address this issue we prove that the mode is not pure gauge and that its negative energy is time-independent and finite. The isometry generators L0 and 0 have non-unitary matrix representations like in logarithmic CFT. While the new mode obeys boundary conditions that are slightly weaker than the ones by Brown and Henneaux, its fall-off behavior is compatible with spacetime being asymptotically AdS3. We employ holographic renormalization to show that the variational principle is well-defined. The corresponding Brown-York stress tensor coincides with that of global AdS3. Finally we address possibilities to eliminate the instability and prospects for chiral gravity.
26.	Henneaux, Marc, et al. (författare) Coxeter group structure of cosmological billiards on compact spatial manifolds 2008 Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479 .- 1126-6708. ; 2008:9, s. 49- Tidskriftsartikel (refereegranskat)abstract We present a systematic study of the cosmological billiard structures of Einstein-p-form systems in which all spatial directions are compactified on a manifold of nontrivial topology. This is achieved for all maximally oxidised theories associated with split real forms, for all possible compactifications as defined by the de Rham cohomology of the internal manifold. In each case, we study the Coxeter group that controls the dynamics for energy scales below the Planck scale as well as the relevant billiard region. We compare and contrast them with the Weyl group and fundamental domain that emerge from the general BKL analysis. For generic topologies we find a variety of possibilities: ( i) The group may or may not be a simplex Coxeter group; ( ii) The billiard region may or may not be a fundamental domain. When it is not a fundamental domain, it can be described as a sequence of pairwise adjacent chambers, known as a gallery, and the reflections in the billiard walls provide a non-standard presentation of the Coxeter group. We find that it is only when the Coxeter group is a simplex Coxeter group, and the billiard region is a fundamental domain, that there is a correspondence between billiard walls and simple roots of a Kac-Moody algebra, as in the general BKL analysis. For each compactification we also determine whether or not the resulting theory exhibits chaotic dynamics.
27.	Henningson, Måns, 1964 (författare) BPS states in (2,0) theory on R x T5 2009 Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479 .- 1126-6708. ; 2009:3 Tidskriftsartikel (refereegranskat)abstract We consider (2, 0) theory on a space-time of the form R x T(5), where the first factor denotes time, and the second factor is a flat spatial five-torus. In addition to their energy, quantum states are characterized by their spatial momentum, 't Hooft flux, and Sp(4) R-symmetry representation. The momentum obeys a shifted quantization law determined by the 't Hooft flux. By supersymmetry, the energy is bounded from below by the magnitude of the momentum. This bound is saturated by BPS states, that are annihilated by half of the supercharges. The spectrum of such states is invariant under smooth deformations of the theory, and can thus be studied by exploiting the interpretation of (2, 0) theory as an ultra-violet completion of maximally supersymmetric Yang-Mills theory on R x T(4). Our main example is the A-series of (2, 0) theories, where such methods allow us to study the spectrum of BPS states for many values of the momentum and the 't Hooft flux. In particular, we can describe the R-symmetry transformation properties of these states by determining the image of their Sp(4) representation in a certain quotient of the Sp(4) representation ring.
28.	Henningson, Måns, 1964 (författare) The low-energy spectrum of (2,0) theory on T5 x R 2008 Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479 .- 1126-6708. ; 2008:11, s. 028- Tidskriftsartikel (refereegranskat)abstract We consider the ADE-series of (2, 0) supersymmetric quantum theories on T(5) x R, where the first factor is a flat spatial five-torus, and the second factor denotes time. The quantum states of such a theory Phi are characterized by a discrete quantum number f is an element of H(3)(T(5), C), where the finite abelian group C is the center subgroup of the corresponding simply connected simply laced Lie group G. At energies that are low compared to the inverse size of the T5, the spectrum consists of a set of continua of states, each of which is characterized by the value of f and some number 5r of additional continuous parameters. By exploiting the interpretation of this theory as the ultraviolet completion of maximally supersymmetric Yang-Mills theory on T(4) x S(1) x R with gauge group G(adj) = G/C and coupling constant g given by the square root of the radius of the S(1) factor, one may compute the number N(f)(r) (Phi) of such continua. We perform these calculations in detail for the A- and D-series. While the Yang-Mills theory formalism is manifestly invariant under the SL(4)(Z) mapping class group of T(4), the results are actually found to be invariant under the SL(5)(Z) mapping class group of T(5), which provides a strong consistency check.
29.	Hornlund, J. L., et al. (författare) The weak coupling spectrum around isolated vacua in N=4 super Yang-Mills on T-3 with any gauge group 2008 Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479 .- 1126-6708. ; 2008:7, s. 34- Tidskriftsartikel (refereegranskat)abstract The moduli space of flat connections for maximally supersymmetric Yang-Mills theories, in a space-time of the form T-3 x R, contains isolated points, corresponding to normalizable zero energy states, for certain simple gauge groups G. We consider the low energy effective field theories in the weak coupling limit supported on such isolated points and find that when quantized they consist of an infinite set of harmonic oscillators whose angular frequencies are completely determined by the Lie algebra of G. We then proceed to find the isolated flat connections for all simple G and subsequently specify the corresponding effective field theories.
30.	Hällgren, Tomas, et al. (författare) Neutrino oscillations in deconstructed dimensions 2005 Ingår i: Journal of High Energy Physics (JHEP). - : IOP Publishing. - 1126-6708 .- 1029-8479. ; 2005:02, s. 049- Tidskriftsartikel (refereegranskat)abstract We present a model for neutrino oscillations in the presence of a deconstructed non-gravitational large extra dimension compactified on the boundary of a two-dimensional disk. In the deconstructed phase, sub-mm lattice spacings are generated from the hierarchy of energy scales between similar to 1 TeV and the usual B - L breaking scale similar to 10(15) GeV. Here, short-distance cutoffs down to similar to 1eV are motivated by the strong coupling behavior of gravity in local discrete extra dimensions. This could make it possible to probe the discretization of extra dimensions and non-trivial field configurations in theory spaces which have only a few sites, i.e., for coarse latticizations. Thus, the model has relevance to present and future precision neutrino oscillation experiments.
31.	Larsen, Kasper, 1983-, et al. (författare) MHV, CSW and BCFW : field theory structures in string theory amplitudes 2008 Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; 11:015, s. 1-59 Tidskriftsartikel (refereegranskat)abstract Motivated by recent progress in calculating field theory amplitudes, we study applications of the basic ideas in these developments to the calculation of amplitudes in string theory. We consider in particular both non-Abelian and Abelian open superstring disk amplitudes in a flat space background, focusing mainly on the four-dimensional case. The basic field theory ideas under consideration split into three separate categories. In the first, we argue that the calculation of α'-corrections to MHV open string disk amplitudes reduces to the determination of certain classes of polynomials. This line of reasoning is then used to determine the α'3-correction to the MHV amplitude for all multiplicities. A second line of attack concerns the existence of an analog of CSW rules derived from the Abelian Dirac-Born-Infeld action in four dimensions. We show explicitly that the CSW-like perturbation series of this action is surprisingly trivial: only helicity conserving amplitudes are non-zero. Last but not least, we initiate the study of BCFW on-shell recursion relations in string theory. These should appear very naturally as the UV properties of the string theory are excellent. We show that all open four-point string amplitudes in a flat background at the disk level obey BCFW recursion relations. Based on the naturalness of the proof and some explicit results for the five-point gluon amplitude, it is expected that this pattern persists for all higher point amplitudes and for the closed string.
32.	Melbéus, Henrik, 1984-, et al. (författare) Searches for hyperbolic extra dimensions at the LHC 2008 Ingår i: Journal of High Energy Physics (JHEP). - : IOP Publishing. - 1126-6708 .- 1029-8479. ; 2008:08, s. 077- Tidskriftsartikel (refereegranskat)abstract We investigate a model of large extra dimensions where the internal space has the geometry of a hyperbolic disc. Compared with the ADD model, this model provides a more satisfactory solution to the hierarchy problem between the electroweak scale and the Planck scale, and it also avoids constraints from astrophysics. In general, a novel feature of this model is that the physical results depend on the position of the brane in the internal space, and in particular, the signal almost disappears completely if the brane is positioned at the center of the disc. Since there is no known analytic form of the Kaluza-Klein spectrum for our choice of geometry, we obtain a spectrum based on a combination of approximations and numerical computations. We study the possible signatures of our model for hadron colliders, especially the LHC, where the most important processes are the production of a graviton together with a hadronic jet or a photon. We find that the signals are similar to those of the ADD model, regarding both qualitative behavior and strength. For the case of hadronic jet production, it is possible to obtain relatively strong signals, while for the case of photon production, this is much more difficult.
33.	Persson, Daniel, 1978, et al. (författare) Finite and infinite-dimensional symmetries of pure N=2 supergravity in D=4 2009 Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479 .- 1126-6708. Tidskriftsartikel (refereegranskat)abstract We study the symmetries of pure N=2 supergravity in D=4. As is known, this theory reduced on one Killing vector is characterised by a non-linearly realised symmetry SU(2,1) which is a non-split real form of SL(3,C). We consider the BPS brane solutions of the theory preserving half of the supersymmetry and the action of SU(2,1) on them. Furthermore we provide evidence that the theory exhibits an underlying algebraic structure described by the Lorentzian Kac-Moody group SU(2,1)^{+++}. This evidence arises both from the correspondence between the bosonic space-time fields of N=2 supergravity in D=4 and a one-parameter sigma-model based on the hyperbolic group SU(2,1)^{++}, as well as from the fact that the structure of BPS brane solutions is neatly encoded in SU(2,1)^{+++}. As a nice by-product of our analysis, we obtain a regular embedding of the Kac-Moody algebra su(2,1)^{+++} in e_{11} based on brane physics.
34.	Petersson, Christoffer, 1979, et al. (författare) Chiral SU(N) gauge theories and the Konishi anomaly 2003 Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479 .- 1126-6708. ; 2003:07, s. 044- Tidskriftsartikel (refereegranskat)abstract We study chiral SU(N) supersymmetric gauge theories with matter in the antifundamental and antisymmetric representations. For SU(5) with two families, we show how to reproduce the non-perturbatively generated superpotential, and we discuss dynamical supersymmetry breaking purely in terms of the Konishi anomaly. We apply the same technique in general to SU(N) with one family. We also briefly comment on the chiral ring for these theories.
35.	Wyllard, Niclas, 1971 (författare) AN-1 conformal Toda field theory correlation functions from conformal N=2 SU(N) quiver gauge theories 2009 Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479 .- 1126-6708. ; 2009:11, s. art no 002- Tidskriftsartikel (refereegranskat)abstract We propose a relation between correlation functions in the 2d A(N-1) conformal Toda theories and the Nekrasov instanton partition functions in certain conformal N = 2 SU(N) 4d quiver gauge theories. Our proposal generalises the recently uncovered relation between the Liouville theory and SU(2) quivers [1]. New features appear in the analysis that have no counterparts in the Liouville case.
36.	Wyllard, Niclas, 1971 (författare) Rigid surface operators and S-duality: some proposals 2009 Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479 .- 1126-6708. ; 2009:5 Tidskriftsartikel (refereegranskat)abstract We study surface operators in the N = 4 supersymmetric Yang-Mills theories with gauge groups SO(n) and Sp(2n). As recently shown by Gukov and Witten these theories have a class of rigid surface operators which are expected to be related by S-duality. The rigid surface operators are of two types, unipotent and semisimple. We make explicit proposals for how the S-duality map should act on unipotent surface operators. We also discuss semisimple surface operators and make some proposals for certain subclasses of such operators.
37.	Arai, Masato, et al. (författare) Hyperkahler sigma models on cotangent bundles of Hermitian symmetric spaces using projective superspace 2007 Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :2, s. 100- Tidskriftsartikel (refereegranskat)abstract Kahler manifolds have a natural hyperkahler structure associated with (part of) their cotangent bundles. Using projective superspace, we construct four-dimensional N=2 models on the tangent bundles of some classical Hermitian symmetric spaces (specifically, the four regular series of irreducible compact symmetric Kahler manifolds, and their non-compact versions). A further dualization yields the Kahler potential for the hyperkahler metric on the cotangent bundle.
38.	Arnlind, Joakim, et al. (författare) Fuzzy Riemann surfaces 2009 Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :6, s. 047- Tidskriftsartikel (refereegranskat)abstract We introduce C-Algebras (quantum analogues of compact Riemann surfaces), defined by polynomial relations in non-commutative variables and containing a real parameter that, when taken to zero, provides a classical non-linear, Poisson-bracket, obtainable from a single polynomial C (onstraint) function. For a continuous class of quartic constraints, we explicitly work out finite dimensional representations of the corresponding C-Algebras.
39.	Beisert, Niklas, et al. (författare) Complete spectrum of long operators in N=4 SYM at one loop 2005 Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; 0507, s. 030- Tidskriftsartikel (refereegranskat)abstract We construct the complete spectral curve for an arbitrary local operator, including fermions and covariant derivatives, of one-loop N=4 gauge theory in the thermodynamic limit. This curve perfectly reproduces the Frolov-Tseytlin limit of the full spectral curve of classical strings on AdS_5xS^5 derived in hep-th/0502226. To complete the comparison we introduce stacks, novel bound states of roots of different flavors which arise in the thermodynamic limit of the corresponding Bethe ansatz equations. We furthermore show the equivalence of various types of Bethe equations for the underlying su(2,2\|4) superalgebra, in particular of the type "Beauty" and "Beast".
40.	Danielsson, Ulf H, et al. (författare) Black holes in asymptotically Lifshitz spacetime 2009 Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :3, s. 070- Tidskriftsartikel (refereegranskat)abstract A model of 3 + 1 dimensional gravity with negative cosmological constant coupled to abelian gauge fields has been proposed as a gravity dual for Lifshitz like critical phenomena in 2 + 1 dimensions. The finite temperature behavior is described by black holes that are asymptotic to the Lifshitz fixed point geometry. There is a one-parameter family of charged black holes, where the magnitude of the charge is uniquely determined by the black hole area. These black holes are thermodynamically stable and become extremal in the limit of vanishing size. The theory also has a discrete spectrum of localized objects described by non-singular spacetime geometries. The finite temperature behavior of Wilson loops is reminiscent of strongly coupled gauge theories in 3 + 1 dimensions, including screening at large distances.
41.	Freyhult, Lisa, 1977-, et al. (författare) Integrable spin chains with U(1)^3 symmetry and generalized Lunin-Maldacena backgrounds. 2005 Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. Tidskriftsartikel (refereegranskat)
42.	Freyhult, Lisa, 1977-, et al. (författare) Rational three-spin string duals and non-anomalous finite size effects. 2005 Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; 05:043 Tidskriftsartikel (refereegranskat)
43.	Freyhult, Lisa, 1977-, et al. (författare) Spiky strings in the SL(2) Bethe Ansatz at strong coupling from AdS/CFT 2009 Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :7, s. 038- Tidskriftsartikel (refereegranskat)abstract We study spiky strings in the context of the SL(2) Bethe ansatz equations. We find an asymmetric distribution of Bethe roots along one cut that determines the all loop anomalous dimension at leading and subleading orders in a large S expansion. At leading order in strong coupling (large lambda) we obtain that the energy of such states is given, in terms of the spin S and the number of spikes n by E-S=n sqrt{lambda}/(2 pi) (ln 16 pi S/(n sqrt{lambda})+ ln sin (pi/n) - 1)+ O(ln S/S). This result matches perfectly the same expansion obtained from the known spiky string classical solution. We then discuss a two cut spiky string Bethe root distribution at one-loop in the SL(2) Bethe ansatz. In this case we find a limit where n goes to infinity, keeping (E+S)/n^2, (E-S)/n, J/n fixed. This is the one loop version of a limit previously considered in the context of the string classical solutions in AdS5 x S5. In that case it was related to a string solution in the AdS pp-wave background.
44.	Hull, Chris M., et al. (författare) Generalized Kahler geometry and gerbes 2009 Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :10, s. 062- Tidskriftsartikel (refereegranskat)abstract We introduce and study the notion of a biholomorphic gerbe with connection. The biholomorphic gerbe provides a natural geometrical framework for generalized Kahler geometry in a manner analogous to the way a holomorphic line bundle is related to Kahler geometry. The relation between the gerbe and the generalized Kahler potential is discussed.
45.	Klose, Thomas, et al. (författare) World-sheet scattering in AdS5 × S5 at two loops 2007 Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :8, s. 051- Tidskriftsartikel (refereegranskat)abstract We study the AdS5 × S5 sigma-model truncated to the near-flat-space limit to two-loops in perturbation theory. In addition to extending previously known one-loop results to the full SU(2\|2)2 S-matrix we calculate the two-loop correction to the dispersion relation and then compute the complete two-loop S-matrix. The result of the perturbative calculation can be compared with the appropriate limit of the conjectured S-matrix for the full theory and complete agreement is found.
46.	Akhmedov, Evgeny, et al. (författare) 1-3 leptonic mixing and the neutrino oscillograms of the Earth 2007 Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :5, s. 077- Tidskriftsartikel (refereegranskat)abstract We develop a detailed and comprehensive description of neutrino oscillations driven by the 1-3 mixing in the matter of the Earth. The description is valid for the realistic (PREM) Earth density profile in the whole range of nadir angles and for neutrino energies above 1 GeV. It can be applied to oscillations of atmospheric and accelerator neutrinos. The results are presented in the form of neutrino oscillograms of the Earth, i.e. the contours of equal oscillation probabilities in the neutrino energy-nadir angle plane. A detailed physics interpretation of the oscilligrams, which includes the MSW peaks, parametric ridges, local maxima, zeros and saddle points, is given in terms of the amplitude and phase conditions. Precise analytic formulas for the probabilities are obtained. We study the dependence of the oscillation pattern on theta(13) and find, in particular, that the survival probability P-ee < 1/2 appears for sin(2) 2 theta(13) as small as similar to 0.009. We consider the dependence of the oscillation pattern on the matter density profile and comment on the possibility of the oscillation tomography of the Earth.
47.	Akhmedov, Evgeny, et al. (författare) Interplay of type I and type II seesaw contributions to neutrino mass 2007 Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :1, s. 043- Tidskriftsartikel (refereegranskat)abstract Type I and type II seesaw contributions to the mass matrix of light neutrinos are inherently related if left-right symmetry is realized at high energy scales. We investigate implications of such a relation for the interpretation of neutrino data. We proved recently that the left-right symmetric seesaw equation has eight solutions, related by a duality property, for the mass matrix of right-handed neutrinos M-R. In this paper the eight allowed structures of M-R are reconstructed analytically and analyzed numerically in a bottom-up approach. We study the dependence of right-handed neutrino masses on the mass spectrum of light neutrinos, mixing angle theta(13), leptonic CP violation, scale of left-right symmetry breaking and on the hierarchy in neutrino Yukawa couplings. The structure of the seesaw formula in several specific SO(10) models is explored in the light of the duality. The outcome of leptogenesis may depend crucially on the choice among the allowed structures of M-R and on the level crossing between right-handed neutrino masses.
48.	Akhmedov, Evgeny, et al. (författare) Stability and leptogenesis in the left-right symmetric seesaw mechanism 2007 Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; 4, s. 022-1-022-25 Tidskriftsartikel (refereegranskat)abstract We analyze the left-right symmetric type I+II seesaw mechanism, where an eight-fold degeneracy among the mass matrices of heavy right-handed neutrinos M-R is known to exist. Using the stability property of the solutions and their ability to lead to successful baryogenesis via leptogenesis as additional criteria, we discriminate among these eight solutions and partially lift their eight-fold degeneracy. In particular, we find that viable leptogenesis is generically possible for four out of the eight solutions.
49.	Arai, Masato, et al. (författare) Polar supermultiplets, Hermitian symmetric spaces and hyperkahler metrics 2007 Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; 12, s. 008- Tidskriftsartikel (refereegranskat)abstract We address the construction of four-dimensional N = 2 supersymmetric non-linear sigma models on tangent bundles of arbitrary Hermitian symmetric spaces startingfrom projective superspace. Using a systematic way of solving the (infinite number of) aux-iliary field equations along with the requirement of supersymmetry, we are able to derivea closed form for the Lagrangian on the tangent bundle and to dualize it to give the hy-perk ̈hler potential on the cotangent bundle. As an application, the case of the exceptional asymmetric space E6 / SO(10) × U(1) is explicitly worked out for the first time.
50.	Benna, Marcus, et al. (författare) Superconformal Chern-Simons theories and AdS(4)/CFT3 correspondence 2008 Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :9, s. 072- Tidskriftsartikel (refereegranskat)abstract We discuss the N = 2 superspace formulation of the N = 8 superconformal Bagger-Lambert-Gustavsson theory, and of the N = 6 superconformal Aharony-Bergman-Jafferis-Maldacena U(N) x U(N) Chern-Simons theory. In particular, we prove the full SU(4)R-symmetry of the ABJM theory. We then consider orbifold projections of this theory that give non-chiral and chiral (U( N) x U(N))(n) superconformal quiver gauge theories. We argue that these theories are dual to certain AdS(4) x S-7/(Z(n) x Z (k$) over tilde) backgrounds of M-theory. We also study a SU(3) invariant mass term in the superpotential that makes the N = 8 theory flow to a N = 2 superconformal gauge theory with a sextic superpotential. We conjecture that this gauge theory is dual to the U(1)(R) x SU(3) invariant extremum of the N = 8 gauged supergravity, which was discovered by N. Warner 25 years ago and whose uplifting to 11 dimensions was found more recently.

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