Journal of High Energy Physics

http://link.springer.com/journal/13130

List of Papers (Total 10,585)

Virtual Compton scattering off a spinless target in AdS/QCD

We study the doubly virtual Compton scattering off a spinless target γ*P → γ*P′ within the Anti-de Sitter(AdS)/QCD formalism. We find that the general structure allowed by the Lorentz invariance and gauge invariance of the Compton amplitude is not easily reproduced with the standard recipes of the AdS/QCD correspondence. In the soft-photon regime, where the semi-classical...

New horizons for black holes and branes

We initiate a systematic scan of the landscape of black holes in any spacetime dimension using the recently proposed blackfold effective worldvolume theory. We focus primarily on asymptotically flat stationary vacuum solutions, where we uncover large classes of new black holes. These include helical black strings and black rings, black odd-spheres, for which the horizon is a...

Parton distributions for event generators

In this paper, conventional global QCD analysis is generalized to produce parton distribution functions (PDFs) optimized for use with event generators at the Large Hadron Collider (LHC). This optimization is accomplished by complementing usual constraints on the PDFs from the existing hard-scattering experimental data with those needed to reproduce cross sections for key...

Holomorphic variables in magnetized brane models with continuous Wilson lines

We analyze the action of the target-space modular group in toroidal type IIB orientifold compactifications with magnetized D-branes and continuous Wilson lines. The transformation of matter fields agree with that of twisted fields in heterotic compactifications, constituting a check of type I/heterotic duality. We identify the holomorphic \(\mathcal{N} \)= 1 variables for these...

Moduli stabilization and cosmology of type IIB on SU(2)-structure orientifolds

We consider type IIB flux compactifications on six-dimensional SU(2)-structure manifolds with O5- and O7-planes. These six-dimensional spaces allow not only for F 3 and H 3 fluxes but also for F 1 and F 5 fluxes. We derive the four-dimensional \( \mathcal {N} \) = 1 scalar potential for such compactifications and present one explicit example of a fully stabilized AdS vacuum with...

Neutrino oscillations: quantum mechanics vs. quantum field theory

A consistent description of neutrino oscillations requires either the quantum-mechanical (QM) wave packet approach or a quantum field theoretic (QFT) treatment. We compare these two approaches to neutrino oscillations and discuss the correspondence between them. In particular, we derive expressions for the QM neutrino wave packets from QFT and relate the free parameters of the QM...

Approximate R-symmetries and the μ term

We discuss the role of approximate U(1) R symmetries for the understanding of hierarchies in Nature. Such symmetries may explain a suppressed expectation value of the superpotential and provide us with a solution to the MSSM μ problem. We present various examples in field theory and string-derived models.

Deep inelastic scattering in conformal QCD

We consider the Regge limit of a CFT correlation function of two vector and two scalar operators, as appropriate to study small-x deep inelastic scattering in \( \mathcal{N} = 4 \) SYM or in QCD assuming approximate conformal symmetry. After clarifying the nature of the Regge limit for a CFT correlator, we use its conformal partial wave expansion to obtain an impact parameter...

Perturbative tests of non-perturbative counting

We observe that a class of quarter-BPS dyons in \( \mathcal{N} = 4 \) theories with charge vector (Q, P) and with nontrivial values of the arithmetic duality invariant I := gcd(Q∧P) are nonperturbative in one frame but perturbative in another frame. This observation suggests a test of the recently computed nonperturbative partition functions for dyons with nontrivial values of...

Quantum field theory, gravity and cosmology in a fractal universe

We propose a model for a power-counting renormalizable field theory living in a fractal spacetime. The action is Lorentz covariant and equipped with a Stieltjes measure. The system flows, even in a classical sense, from an ultraviolet regime where spacetime has Hausdorff dimension 2 to an infrared limit coinciding with a standard D-dimensional field theory. We discuss the...

Charged magnetic brane solutions in AdS5 and the fate of the third law of thermodynamics

We construct asymptotically AdS5 solutions to 5-dimensional Einstein-Maxwell theory with Chern-Simons term which are dual to 4-dimensional gauge theories, including \(\mathcal{N} = 4 \) SYM theory, in the presence of a constant background magnetic field B and a uniform electric charge density ρ. For the solutions corresponding to supersymmetric gauge theories, we find numerically...

Towards a holographic model of color-flavor locking phase

We demonstrate a holographic realization of color-flavor locking phase, using \( \mathcal{N} \) = 4 SU(N c ) SYM coupled to \( \mathcal{N} \) = 2 N f fundamental hypermultiplets as an example. The gravity dual consists of N c D3-branes and N f D7-branes with world volume gauge field representing the baryon density. Treating a small number Ñ c \( \subset \) N c of D3-branes as...

Observations on arithmetic invariants and U-duality orbits in \( \mathcal {N} \) = 8 supergravity

We establish a relation between time-like, light-like and space-like orbits of the non-compact E 7(7)(\(\mathbb{R} \)) symmetry and discrete E 7(7)(\(\mathbb{Z} \)) invariants. We discuss the Uduality invariant formula for the degeneracy of states \( d (\mathcal{Q}) \) which in the approximation of large occupation numbers reproduces the Bekenstein-Hawking entropy formula for...

Goldstini

Supersymmetric phenomenology has been largely bound to the hypothesis that supersymmetry breaking originates from a single source. In this paper, we relax this underlying assumption and consider a multiplicity of sectors which independently break supersymmetry, thus yielding a corresponding multiplicity of goldstini. While one linear combination of goldstini is eaten via the...

Dileptonic signatures of T-odd quarks at the LHC

Little Higgs models are often endowed with a T-parity in order to satisfy electroweak precision tests and give at the same time a stable particle which is a candidate for cold dark matter. This type of models predicts a set of new T-odd fermions in addition to the heavy gauge bosons of the Little Higgs models, which may show interesting signatures at colliders. In this paper, we...

Supergravity solutions from floating branes

We simplify the equations of motion of five-dimensional ungauged supergravity coupled to three U(1) gauge fields using a floating-brane Ansatz in which the electric potentials are directly related to the gravitational warp factors. We find a new class of non-BPS solutions, that can be obtained linearly starting from an Euclidean four-dimensional Einstein-Maxwell base. This class...

Holographic superconductor/insulator transition at zero temperature

We analyze the five-dimensional AdS gravity coupled to a gauge field and a charged scalar field. Under a Scherk-Schwarz compactification, we show that the system undergoes a superconductor/insulator transition at zero temperature in 2 + 1 dimensions as we change the chemical potential. By taking into account a confinement/deconfinement transition, the phase diagram turns out to...

D1D5 microstate geometries from string amplitudes

We reproduce the asymptotic expansion of the D1D5 microstate geometries by computing the emission amplitudes of closed string states from disks with mixed D1D5 boundary conditions. Thus we provide a direct link between the supergravity and D-brane descriptions of the D1D5 microstates at non-zero string coupling. Microscopically, the profile functions characterizing the microstate...

R4 couplings and automorphic unipotent representations

Four-graviton, eight-derivative couplings in the low energy effective action of toroidal type II string compactifications are tightly constrained by U-duality invariance and by supersymmetry. In this note, we revisit earlier proposals for the automorphic form governing these couplings in dimension D = 3, 4, 5, 6, and propose that the correct automorphic form is the minimal theta...

Photoemission “experiments” on holographic superconductors

We study the effects of a superconducting condensate on holographic Fermi surfaces. With a suitable coupling between the fermion and the condensate, there are stable quasiparticles with a gap. We find some similarities with the phenomenology of the cuprates: in systems whose normal state is a non-Fermi liquid with no stable quasiparticles, a stable quasiparticle peak appears in...

Quasinormal modes of massive charged flavor branes

We present an analysis and classiffication of vector and scalar fluctuations in a D3/D7-brane setup at finite temperature and baryon density. The system is dual to an \( \mathcal{N} = 2 \) supersymmetric Yang-Mills theory with SU(N c ) gauge group and N f hyper-multiplets in the fundamental representation in the quenched approximation. We improve significantly over previous...

The S-matrix in twistor space

The marvelous simplicity and remarkable hidden symmetries recently uncovered in (Super) Yang-Mills and (Super)Gravity scattering amplitudes strongly suggests the existence of a “weak-weak” dual formulation of these theories where these structures are made more manifest at the expense of manifest locality. In this note we suggest that in four dimensions, this dual description...

Finite-temperature fractional D2-branes and the deconfinement transition in 2+1 dimensions

The supergravity dual to N regular and M fractional D2-branes on a cone over \( \mathbb{C}{\mathbb{P}^3} \) has a naked singularity in the infrared. One can resolve this singularity and obtain a regular fractional D2-brane solution dual to a confining 2+1 dimensional \( \mathcal{N} = 1 \) supersymmetric field theory. The confining vacuum of this theory is described by the...

More on the connection between planar field theory and string theory

We continue work on the connection between world sheet representation of the planar ϕ 3 field theory and string formation. The present article, like the earlier work, is based on the existence of a solitonic solution on the world sheet, and on the zero mode fluctuations around this solution. The main advance made in this paper is the removal of the cutoff and the transition to...

On the relation between hybrid and pure spinor string theory

In this paper we revisit Berkovits’ pure spinor formalism in lower dimensions. We are particularly interested in relating a six-dimensional pure spinor action previously constructed in the literature to other superstring formalisms. In order to gain some insight into six-dimensional pure spinors, we first derive their action by gauge-fixing the classical six-dimensional Green...