Journal of High Energy Physics

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

List of Papers (Total 9,610)

ABJM baryon stability and Myers effect

We consider magnetically charged baryon vertex like configurations in AdS 4 × CP 3 with a reduced number of quarks l. We show that these configurations are solutions to the classical equations of motion and are stable beyond a critical value of l. Given that the magnetic flux dissolves D0-brane charge it is possible to give a microscopical description in terms of D0-branes ...

Symmetry and mass degeneration in multi-Higgs-doublet models

We investigate possible symmetry properties of the scalar sector of Multi-Higgs-Doublet Models, and, to some extent, the generalization of such models to gauge groups other than SU(2) L × U(1) Y . In models with C (charge conjugation) invariance, and where certain quartic terms are not present, the scalar potential is invariant under a group larger than the gauge group, O(4) when ...

Complete resummation of chirally-enhanced loop-effects in the MSSM with non-minimal sources of flavor-violation

In this article we present the complete resummation of the leading chirallyenhanced corrections stemming from gluino-squark, chargino-sfermion and neutralino-sfermion loops in the MSSM with non-minimal sources of flavor-violation. We compute the finite renormalization of fermion masses and the CKM matrix induced by chirality-flipping self-energies. In the decoupling limit M SUSY ≫ ...

Vector boson pair production at the LHC

We present phenomenological results for vector boson pair production at the LHC, obtained using the parton-level next-to-leading order program MCFM. We include the implementation of a new process in the code, pp → γγ, and important updates to existing processes. We incorporate fragmentation contributions in order to allow for the experimental isolation of photons in γγ, Wγ, and Zγ ...

Light Higgsinos as heralds of higher-dimensional unification

Grand-unified models with extra dimensions at the GUT scale will typically contain exotic states with Standard Model charges and GUT-scale masses. They can act as messengers for gauge-mediated supersymmetry breaking. If the number of messengers is sizeable, soft terms for the visible sector fields will be predominantly generated by gauge mediation, while gravity mediation can ...

The dropping of in-medium hadron mass in holographic QCD

We study the baryon density dependence of the vector meson spectrum using the D4/D6 system together with the compact D4 baryon vertex. We find that the vector meson mass decreases almost linearly in density at low density for small quark mass, but saturates to a finite non-zero value for large density. We also compute the density dependence of the η′ mass and the η′ velocity. We ...

A weakly constrained W′ at the early LHC

We study, within an effective approach, the phenomenology of a charged W′ vector which transforms as an isosinglet under the Standard Model gauge group. We discuss bounds from present data, finding that these are quite weak for suitable choices of the right-handed quark mixing matrix. Then we study the resonant production at the early LHC of such a weakly constrained W′. We start ...

A black ring with two angular momenta in Taub-NUT

We use the recently-constructed explicit duality transformation that relates a rotating \( \overline {{\text{D}}6} {\text{ - D}}4{\text{ - D}}2{\text{ - D}}0 \) black hole solution to a rotating M5-M2-P black string to construct a non-supersymmetric black ring in Taub-NUT that has two angular momenta, as well as M2 charges and M5 dipole moments. This is the first black ring ...

The hypermultiplet with Heisenberg isometry in N = 2 global and local supersymmetry

The string coupling of N = 2 supersymmetric compactifications of type II string theory on a Calabi-Yau manifold belongs to the so-called universal dilaton hyper-multiplet, that has four real scalars living on a quaternion-Kähler manifold. Requiring Heisenberg symmetry, which is a maximal subgroup of perturbative isometries, reduces the possible manifolds to a one-parameter family ...

MadGraph 5: going beyond

MadGraph 5 is the new version of the MadGraph matrix element generator, written in the Python programming language. It implements a number of new, efficient algorithms that provide improved performance and functionality in all aspects of the program. It features a new user interface, several new output formats including C++ process libraries for Pythia 8, and full compatibility ...

Higgs friends and counterfeits at hadron colliders

We consider the possibility of “Higgs counterfeits” - scalars that can be produced with cross sections comparable to the SM Higgs, and which decay with identical relative observable branching ratios, but which are nonetheless not responsible for electroweak symmetry breaking. We also consider a related scenario involving “Higgs friends,” fields similarly produced through gg fusion ...

CP violation and FCNC in a warped A4 flavor model

We recently proposed a spontaneous A4 flavor symmetry breaking scheme implemented in a warped extra dimensional setup to explain the observed pattern of quark and lepton masses and mixings. The quark mixing is absent at leading order in the VEV expansion and it is induced at next-to-leading order by bulk A4 flavons mediating “crossbrane” interactions and a “cross-talk” between the ...

Perturbative quantum gravity with the Immirzi parameter

We study perturbative quantum gravity in the first-order tetrad formalism. The lowest order action corresponds to Einstein-Cartan plus a parity-odd term, and is known in the literature as the Holst action. The coupling constant of the parity-odd term can be identified with the Immirzi parameter γ of loop quantum gravity. We compute the quantum effective action in the one-loop ...

Exploring new physics in the C 7-C 7′ plane

The Wilson coefficient C 7 governing the radiative electromagnetic decays of B meson has been calculated toa very high accuracy in the Standard Model, but experimental bounds on either the magnitude or the sign of C 7 are often model-dependent. In the present paper, we attempt at constraining both the magnitude and sign of C 7 using a systematic approach. We consider already ...

The one-loop six-dimensional hexagon integral and its relation to MHV amplitudes in \( \mathcal{N} = 4 \) SYM

We provide an analytic formula for the (rescaled) one-loop six-dimensional scalar hexagon integral \( {\tilde{\Phi }_6} \) with all external legs massless, in terms of classical polylogarithms. We show that this integral is closely connected to two integrals appearing in one-and two-loop amplitudes in planar \( \mathcal{N} = 4 \) super-Yang-Mills theory, Ω(1) and Ω(2). The ...

Search for supersymmetry in events with a lepton, a photon, and large missing transverse energy in pp collisions at \( \sqrt {s} = 7 \) TeV

A search is performed for an excess of events, over the standard model expectations, with a photon, a lepton, and large missing transverse energy in pp collisions at \( \sqrt {s} = 7 \) TeV. Such events are expected in many new physics models, in particular a supersymmetric theory that is broken via a gauge-mediated mechanism, when the lightest charged and neutral gauginos are mass ...

Small black hole constituents and horizontal symmetry

By exploiting the role of the horizontal symmetry \( S{L_h}\left( {2,\mathbb{R}} \right) \), we extend the analysis and classification of two-centered extremal black hole charge configurations to the case of “small” single-centered constituents. These latter are seen to decrease the number of independent horizontal-invariant polynomials from four to one, depending on the rank of ...

Search for new physics with same-sign isolated dilepton events with jets and missing transverse energy at the LHC

The results of searches for new physics in events with two same-sign isolated leptons, hadronic jets, and missing transverse energy in the final state are presented. The searches use an integrated luminosity of 35 pb−1 of pp collision data at a centre-of-mass energy of 7 TeV collected by the CMS experiment at the LHC. The observed numbers of events agree with the standard model ...

First-order flows and stabilisation equations for non-BPS extremal black holes

We derive a generalised form of flow equations for extremal static and rotating non-BPS black holes in four-dimensional ungauged N = 2 supergravity coupled to vector multiplets. For particular charge vectors, we give stabilisation equations for the scalars, analogous to the BPS case, describing full known solutions. Based on this, we propose a generic ansatz for the stabilisation ...

Correlations in double parton distributions at small x

We present a dynamical study of the double parton distribution in impact parameter space, which enters into the double scattering cross section in hadronic collisions. This distribution is analogous to the generalized parton densities in momentum space. We use the Lund Dipole Cascade model, presented in earlier articles, which is based on BFKL evolution including essential higher ...

Easy Dirac gauginos

A simple and natural model is presented that gives Dirac gauginos. The configuration is related to “deconstructed gaugino mediation”. A high energy completion is provided based on existing ISS-like models of deconstructed gaugino mediation. This provides a complete picture of Dirac gauginos that includes the necessary extra adjoint fermions (generated as magnetic quarks of the ISS ...

Reduced branching ratio for H → AA → 4 τ from A − η b mixing

Models with an extended Higgs sector, as the NMSSM, allow for scenarios where the Standard Model-like CP-even Higgs boson H decays dominantly as H → AA → 4τ where A is a light CP-odd Higgs boson. Tight constraints on this scenario in the form of lower bounds on M H have recently been published by the ALEPH group. We show that, due to A − η b mixing, the branching ratio H → AA → 4τ ...

Jet substructure without trees

We present an alternative approach to identifying and characterizing jet substructure. An angular correlation function is introduced that can be used to extract angular and mass scales within a jet without reference to a clustering algorithm. This procedure gives rise to a number of useful jet observables. As an application, we construct a top quark tagging algorithm that is ...

Massless D-strings and moduli stabilization in type I cosmology

We consider the cosmological evolution induced by the free energy F of a gas of maximally supersymmetric heterotic strings at finite temperature and weak coupling in dimension D ≥ 4. We show that F, which plays the role of an effective potential, has minima associated to enhanced gauge symmetries, where all internal moduli can be attracted and dynamically stabilized. Using the fact ...