Journal of High Energy Physics

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

List of Papers (Total 10,500)

Dark force detection in low energy e-p collisions

We study the prospects for detecting a light boson X with mass m X ≾ 100 MeV at a low energy electron-proton collider. We focus on the case where X dominantly decays to e + e − as motivated by recent “dark force” models. In order to evade direct and indirect constraints, X must have small couplings to the standard model (α X ≾ 10−8) and a sufficiently large mass (m X ≳ 10 MeV...

Hamiltonian dynamics and the hidden symmetries of the AdS 5 × S 5 superstring

We construct the Lax connection of the Green-Schwarz superstring in AdS 5 × S 5 within the Hamiltonian formalism and obtain precisely that used in 0810.4136. It differs in a crucial way from the Bena-Polchinski-Roiban connection by terms proportional to the Hamiltonian constraints. These extra terms ensure firstly that the integrals of motion are all first class and secondly that...

Witten index in supersymmetric 3d theories revisited

We have performed a direct calculation of Witten index I in \( \mathcal{N} = 1,2,3 \) supersymmetric Yang-Mills Chern-Simons (SYMCS) 3d theories. We do it in the framework of Born-Oppenheimer (BO) approach by putting the system into a small spatial box and studying the effective Hamiltonian depending on the zero field harmonics. At the tree level, our results coincide with the...

Towards a non-abelian electric-magnetic symmetry: the skeleton group

We propose an electric-magnetic symmetry group in non-abelian gauge theory, which we call the skeleton group. We work in the context of non-abelian unbroken gauge symmetry, and provide evidence for our proposal by relating the representation theory of the skeleton group to the labelling and fusion rules of charge sectors. We show that the labels of electric, magnetic and dyonic...

Heterotic resolved conifolds with torsion, from supergravity to CFT

We obtain a family of heterotic supergravity backgrounds describing warped non-Kähler conifolds with three-form flux and an Abelian gauge bundle, preserving \( \mathcal{N} \) = 1 supersymmetry in four dimensions. At large distance from the singularity the usual Ricci- at conifold is recovered. By performing a ℤ2 orbifold of the T 1,1 base, the conifold singularity can be blown-up...

Kahler moduli inflation revisited

We perform a detailed numerical analysis of inflationary solutions in Kahler moduli of type IIB flux compactifications. We show that there are inflationary solutions even when all the fields play an important role in the overall shape of the scalar potential. Moreover, there exists a direction of attraction for the inflationary trajectories that correspond to the constant volume...

Toric Lego: a method for modular model building

Within the context of local type IIB models arising from branes at toric Calabi-Yau singularities, we present a systematic way of joining any number of desired sectors into a consistent theory. The different sectors interact via massive messengers with masses controlled by tunable parameters. We apply this method to a toy model of the minimal supersymmetric standard model (MSSM...

Heavy-light mesons in the ϵ-regime

We study the finite-size scaling of heavy-light mesons in the static limit. We compute two-point functions of chiral current densities as well as pseudoscalar densities in the ϵ-regime of heavy meson Chiral Perturbation Theory (HMChPT). As expected, finite volume dependence turns out to be significant in this regime and can be predicted in the effective theory in terms of the...

Scattering amplitudes and BCFW recursion in twistor space

Twistor ideas have led to a number of recent advances in our understanding of scattering amplitudes. Much of this work has been indirect, determining the twistor space support of scattering amplitudes by examining the amplitudes in momentum space. In this paper, we construct the actual twistor scattering amplitudes themselves. We show that the recursion relations of Britto...

DBI analysis of generalised permutation branes

We investigate D-branes on the product G×G of two group manifolds described as Wess-Zumino-Novikov-Witten models. When the levels of the two groups coincide, it is well known that there exist permutation D-branes which are twisted by the automorphism exchanging the two factors. When the levels are different, the D-brane charge group demands that there should be generalisations of...

Strong dark matter constraints on GMSB models

We reconsider the dark matter problem in supersymmetric models with gauge mediated supersymmetry breaking, with and without R-parity breaking. In these classes of models, a light gravitino forms the dark matter. Consistency with the experimental data, in particular the dark matter abundance and the small-scale power spectrum, requires additional entropy production after the...

Radiative corrections to the neutral-current Drell-Yan process in the Standard Model and its minimal supersymmetric extension

An adequate description of the neutral-current Drell-Yan process at the Tevatron and the LHC, in particular, requires the inclusion of electroweak radiative corrections. We extend earlier work in this direction in various ways. First, we define and numerically compare different methods to describe the Z-boson resonance including next-to-leading order electroweak corrections...

Canonical analysis of algebraic string actions

We investigate the canonical aspects of the algebraic first order formulation of strings introduced two decades ago by Balachandran and collaborators. We slightly enlarge the Lagrangian framework and show the existence of a self-dual formulation and of an Immirzi-type parameter reminiscent of four-dimensional first order gravity. We perform a full Hamiltonian analysis of the self...

Measuring slepton masses and mixings at the LHC

Flavor physics may help us understand theories beyond the standard model. In the context of supersymmetry, if we can measure the masses and mixings of sleptons and squarks, we may learn something about supersymmetry and supersymmetry breaking. Here we consider a hybrid gauge-gravity supersymmetric model in which the observed masses and mixings of the standard model leptons are...

Extremal black holes, nilpotent orbits and the true fake superpotential

Dimensional reduction along time offers a powerful way to study stationary solutions of 4D symmetric supergravity models via group-theoretical methods. We apply this approach systematically to extremal, BPS and non-BPS, spherically symmetric black holes, and obtain their “fake superpotential” W. The latter provides first order equations for the radial problem, governs the mass...

Feynman rules for the rational part of the electroweak 1-loop amplitudes

We present the complete set of Feynman rules producing the rational terms of kind R2 needed to perform any 1-loop calculation in the Electroweak Standard Model. Our results are given both in the ’t Hooft-Veltman and in the Four Dimensional Helicity regularization schemes. We also verified, by using both the ’t Hooft-Feynman gauge and the Background Field Method, a huge set of...

One-loop Higgs plus four gluon amplitudes: full analytic results

We consider one-loop amplitudes of a Higgs boson coupled to gluons in the limit of a large top quark mass. We treat the Higgs as the real part of a complex field ϕ that couples to the self-dual field strengths and compute the one-loop corrections to the ϕ-NMHV amplitude, which contains one gluon of positive helicity whilst the remaining three have negative helicity. We use four...

Constructing all-order corrections to multi-jet rates

We discuss the universal behaviour of scattering cross sections in the limit of infinite rapidity separation between all produced particles, and illustrate the behaviour explicitly for the production of n jets, W + n jets, Z + n jets for n = 2, 3, 4, and for H + 2, 3 jets. We give a set of rules for constructing scattering cross sections, which are exact in the given limit, and...

Decoupling of unphysical states in the minimal pure spinor formalism I

This is the first of a series of two papers where decoupling of unphysical states in the minimal pure spinor formalism is investigated. The multi-loop amplitude prescription for the minimal pure spinor superstring formulated in hep-th/0406055 involves the insertion of picture changing operators in the path integral. These operators are BRST closed in a distributional sense and...

No forbidden landscape in string/M-theory

Scale invariant but non-conformal field theories are forbidden in (1 + 1) dimension, and so should be the corresponding holographic dual gravity theories. We conjecture that such scale invariant but non-conformal field configurations do not exist in the string/M-theory. We provide a proof of this conjecture in the classical supergravity limit when the space-time is trivially...

On supersymmetric D7-branes in the warped deformed conifold

We study the supersymmetric properties of D7-branes in the warped deformed conifold. We consider the κ-symmetry conditions on D7-branes in this specific warped background, taking into account the background NS-NS 2-form flux. While any holomorphic embedding defines a supersymmetric D7-brane in the absence of background H-flux, most of the D7-brane embeddings considered in the...

D-brane inspired fermion mass textures

In this paper, the issues of the quark mass hierarchies and the Cabbibo Kobayashi Maskawa mixing are analyzed in a class of intersecting D-brane configurations with Standard Model gauge symmetry. The relevant mass matrices are constructed taking into account the constraints imposed by extra abelian symmetries and anomaly cancelation conditions. Possible mass generating mechanisms...

Non-unitary leptonic mixing and leptogenesis

We investigate the relation between non-unitarity of the leptonic mixing matrix and leptogenesis. We discuss how all parameters of the canonical type-I seesaw mechanism can, in principle, be reconstructed from the neutrino mass matrix and the deviation of the effective low-energy leptonic mixing matrix from unitary. When the mass M′ of the lightest right-handed neutrino is much...

Simplifying the tree-level superstring massless five-point amplitude

We use the pure spinor formalism to obtain the supersymmetric massless five-point amplitude at tree-level in a streamlined fashion. We also prove the equivalence of an OPE identity in string theory with a subset of the Bern-Carrasco-Johansson five-point kinematic relations, and demonstrate how the remaining BCJ identities follow from the different integration regions over the...

MSSM baryogenesis and electric dipole moments: an update on the phenomenology

We explore the implications of electroweak baryogenesis for future searches for permanent electric dipole moments in the context of the minimal supersymmetric extension of the Standard Model (MSSM). From a cosmological standpoint, we point out that regions of parameter space that over-produce relic lightest supersymmetric particles can be salvaged only by assuming a dilution of...