Journal of High Energy Physics

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

List of Papers (Total 9,431)

Holographic superconductors from gauged supergravity

We consider minimal setups arising from different truncations of \( \mathcal{N} = 8 \) five-dimensional SO(6) gauged supergravity to study phase transitions involving spontaneous breaking of any of the U(1) symmetries in U(1) × U(1) × U(1) ⊂ SO(6). These truncations only keep the three relevant vector fields, four complex scalar fields carrying U(1) charges, plus two neutral scalar ...

Composite GUTs: models and expectations at the LHC

We investigate grand unified theories (GUTs) in scenarios where electroweak (EW) symmetry breaking is triggered by a light composite Higgs, arising as a Nambu-Goldstone boson from a strongly interacting sector. The evolution of the standard model (SM) gauge couplings can be predicted at leading order, if the global symmetry of the composite sector is a simple group \( \mathcal{G} ...

How to halve maximal supergravity

We work out the truncation from maximal to half-maximal supergravity in four dimensions. In particular, we determine the explicit constraints on the embedding tensors of both theories. These tensors specify the complete theories, including gauge groups and scalar potentials. Firstly, we find the linear constraint on \( \mathcal{N} = 8 \) theories to allow for a truncation to \( ...

Search for physics beyond the standard model in opposite-sign dilepton events in pp collisions at \( \sqrt {s} = 7\,{\text{TeV}} \)

A search is presented for physics beyond the standard model (SM) in final states with opposite-sign isolated lepton pairs accompanied by hadronic jets and missing transverse energy. The search is performed using LHC data recorded with the CMS detector, corresponding to an integrated luminosity of 34 pb−1. No evidence for an event yield beyond SM expectations is found. An upper ...

Quantum black holes, localization, and the topological string

We use localization to evaluate the functional integral of string field theory on AdS 2 × S 2 background corresponding to the near horizon geometry of supersymmetric black holes in 4d compactifications with \( \mathcal{N} = 2 \) supersymmetry. In particular, for a theory containing n v + 1 vector multiplets, we show that the functional integral localizes exactly onto an ordinary ...

Identifying dark matter event topologies at the LHC

Assuming dark matter particles can be pair-produced at the LHC from cascade decays of heavy particles, we investigate strategies to identify the event topologies based on the kinematic information of final state visible particles. This should be the first step towards measuring the masses and spins of the new particles in the decay chains including the dark matter particle. As a ...

The open string membrane paradigm with external electromagnetic fields

We study the effective geometry felt by the fluctuations of open strings living on the worldvolume of probe D-branes in the presence of background electromagnetic fields. This is captured by an effective action consisting of a Maxwell term and a topological term, with the role of the metric played by the open string metric. Studying generalized Eddington-Finkelstein coordinates for ...

Spin-2 spectrum of defect theories

We study spin-2 excitations in the background ofthe recently-discovered type-IIB solutions of D’Hoker et al. These are holographically-dual to defect conformal field theories, and they are also of interest in the context of the Karch-Randall proposal for a string-theory embedding of localized gravity. We first generalize an argument by Csaki et al to show that for any solution with ...

Exploring the CP-violating Inert-Doublet Model

We have explored properties of an extension of the Inert Doublet Model by the addition of an extra non-inert scalardoublet. The model offers a possibility of CP violation in the scalar sector and a candidate for the Dark Matter. Allowed regions in the plane spanned by the mass of the Dark-Matter particle and the lightest neutral Higgs particle have been identified, and constraints ...

SUSY renormalization group effects in ultra high energy neutrinos

We have explored the question of whether the renormalization group running of the neutrino mixing parameters in the Minimal Supersymmetric Standard Model is detectable with ultra-high energy neutrinos from active galactic nuclei (AGN). We use as observables the ratios of neutrino fluxes produced at the AGN, focusing on four different neutrino production models: \( \left( ...

String solitons and T-duality

We construct for arbitrary dimensions a universal T-duality covariant expression for the Wess-Zumino terms of supersymmetric String Solitons in toroidally compactified string theories with 32 supercharges. The worldvolume fields occurring in the effective action of these String Solitons form either a vector or a tensor multiplet with 16 supercharges. We determine the dimensions of ...

Lovelock theories, holography and the fate of the viscosity bound

We consider Lovelock theories of gravity in the context of AdS/CFT. We show that, for these theories, causality violation on a black hole background can occur well in the interior of the geometry, thus posing more stringent constraints than were previously found in the literature. Also, we find that instabilities of the geometry can appear for certain parameter values at any point ...

Inclusive measurements of inelastic electron and positron scattering from unpolarized hydrogen and deuterium targets

Results of inclusive measurements of inelastic electron and positron scattering from unpolarized protons and deuterons at the HERMES experiment are presented. The structure functions F 2 p and F 2 d are determined using a parameterization of existing data for the longitudinal-to-transverse virtual-photon absorption cross-section ratio. The HERMES results provide data in the ranges ...

Magnetic phase diagram of dense holographic multiquarks in the quark-gluon plasma

We study phase diagram of the dense holographic gauge matter in the Sakai-Sugimoto model in the presence of the magnetic field above the deconfinement temperature. Even above the deconfinement, quarks could form colour bound states through the remaining strong interaction if the density is large. We demonstrate that in the presence of the magnetic field for a sufficiently large ...

Black funnels and droplets in thermal equilibrium

It has recently been proposed that the strong coupling behaviour of quantum field theories on a non-dynamical black hole background can be described, in the context of the AdS/CFT correspondence, by a competition between two gravity duals: a black funnel and a black droplet. We present here thermal equilibrium solutions which represent such spacetimes, providing the first example ...

Fine-tuning implications for complementary dark matter and LHC SUSY searches

The requirement that SUSY should solve the hierarchy problem without undue fine-tuning imposes severe constraints on the new supersymmetric states. With the MSSM spectrum and soft SUSY breaking originating from universal scalar and gaugino masses at the Grand Unification scale, we show that the low-fine-tuned regions fall into two classes that will require complementary collider ...

Lopsided gauge mediation

It has been recently pointed out that the unavoidable tuning among supersymmetric parameters required to raise the Higgs boson mass beyond its experimental limit opens up new avenues for dealing with the so called μ-B μ problem of gauge mediation. In fact, it allows for accommodating, with no further parameter tuning, large values of B μ and of the other Higgs-sector soft masses, ...

Dynamic SU(2) structure from seven-branes

We obtain a family of supersymmetric solutions of type IIB supergravity with dynamic SU(2) structure, which describe the local geometry near a stack of four D7-branes and one O7-plane wrapping a rigid four-cycle. The deformation to a generalized complex geometry is interpreted as a consequence of nonperturbative effects in the seven-brane gauge theory. We formulate the problem for ...

Simple loop integrals and amplitudes in \( \mathcal{N} = 4 \) SYM

We use momentum twistors to evaluate planar loop integrals. Infrared divergences are regulated by the recently proposed AdS-inspired mass regulator. We show that two-loop amplitudes in \( \mathcal{N} = 4 \) super Yang-Mills can be expanded in terms of basis integrals having twistor numerators. We argue that these integrals are considerably simpler compared to the ones ...

Cascades with adjoint matter: adjoint transitions

A large class of duality cascades based on quivers arising from non-isolated singularities enjoy adjoint transitions-a phenomenon which occurs when the gauge coupling of a node possessing adjoint matter is driven to strong coupling in a manner resulting in a reduction of rank in the non-Abelian part of the gauge group and a subsequent flow to weaker coupling. We describe adjoint ...

Metastable supersymmetry breaking in extended supergravity

We consider the stability of non-supersymmetric critical points of general \( \mathcal{N} = 4 \) supergravities. A powerful method to analyse this issue based on the sGoldstino direction has been developed for minimal supergravity. We adapt this to the present case, and address the conceptually new features arising for extended supersymmetry. As an application, we investigate the ...

LHC bounds on large extra dimensions

We derive new dominant bounds on the coefficient of the effective operator generated by tree-level graviton exchange in large extra dimensions from pp → jj data at LHC: M T > 2.1 TeV (ATLAS after 3.1/pb of integrated luminosity), M T > 3.4 TeV (CMS after 36/pb), M T > 3.2 TeV (ATLAS after 36/pb). We clarify the role of on-shell graviton exchange and compare the full graviton ...

Search for resonances in the dilepton mass distribution in pp collisions at \( \sqrt {s} = 7 \) TeV

A search for narrow resonances at high mass in the dimuon and dielectron channels has been performed by the CMS experiment at the CERN LHC, using pp collision data recorded at \( \sqrt {s} = 7 \) TeV. The event samples correspond to integrated luminosities of 40 pb−1 in the dimuon channel and 35 pb−1 in the dielectron channel. Heavy dilepton resonances are predicted in theoretical ...

Search for large extra dimensions in the diphoton final state at the Large Hadron Collider

A search for large extra spatial dimensions via virtual-graviton exchange in the diphoton channel has been carried out with the CMS detector at the LHC. No excess of events above the standard model expectations is found using a data sample collected in proton-proton collisions at \( \sqrt {s} = 7 \) TeV and corresponding to an integrated luminosity of 36 pb− 1. New lower limits on ...