Journal of High Energy Physics

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

List of Papers (Total 9,782)

Labelled tree graphs, Feynman diagrams and disk integrals

In this note, we introduce and study a new class of “half integrands” in Cachazo-He-Yuan (CHY) formula, which naturally generalize the so-called Parke-Taylor factors; these are dubbed Cayley functions as each of them corresponds to a labelled tree graph. The CHY formula with a Cayley function squared gives a sum of Feynman diagrams, and we represent it by a combinatoric polytope ...

A complete basis of helicity operators for subleading factorization

Factorization theorems underly our ability to make predictions for many processes involving the strong interaction. Although typically formulated at leading power, the study of factorization at subleading power is of interest both for improving the precision of calculations, as well as for understanding the all orders structure of QCD. We use the SCET helicity operator formalism to ...

Angular distribution of polarised Λ b baryons decaying to Λℓ + ℓ −

Rare b → sℓ + ℓ − flavour-changing-neutral-current processes provide important tests of the Standard Model of particle physics. Angular observables in exclusive b → sℓ + ℓ − processes can be particularly powerful as they allow hadronic uncertainties to be controlled. Amongst the exclusive processes that have been studied by experiments, the decay Λ b → Λℓ + ℓ − is unique in that ...

Spontaneous CP violation in multi-Higgs potentials with triplets of Δ(3n 2) and Δ(6n 2)

Motivated by discrete flavour symmetry models, we analyse Spontaneous CP Violation (SCPV) for potentials involving three or six Higgs fields (both electroweak doublets and singlets) which fall into irreducible triplet representations of discrete symmetries belonging to the Δ(3n 2) and Δ(6n 2) series, including A 4, S 4, Δ(27) and Δ(54). For each case, we give the potential and find ...

Kinematic space for conical defects

Kinematic space can be used as an intermediate step in the AdS/CFT dictionary and lends itself naturally to the description of diffeomorphism invariant quantities. From the bulk it has been defined as the space of boundary anchored geodesics, and from the boundary as the space of pairs of CFT points. When the bulk is not globally AdS3 the appearance of non-minimal geodesics leads ...

Self-consistency of conformally coupled ABJM theory at the quantum level

We study the \( \mathcal{N} \) = 6 superconformal Chern-Simons matter field theory (the ABJM theory) conformally coupled to a Lorentzian, curved background spacetime. To support rigid supersymmetry, such backgrounds have to admit twistor spinors. At the classical level, the symmetry of the theory can be described by a conformal symmetry superalgebra. We show that the full \( ...

Solving the Bars-Green equation for moving mesons in two-dimensional QCD

The two-dimensional QCD in the large N limit, generally referred to as the ’t Hooft model, is numerically investigated in the axial gauge in a comprehensive manner. The corresponding Bethe-Salpeter equation for a bound \( q\overline{q} \) pair, originally derived by Bars and Green in 1978, was first numerically tackled by Li and collaborators in late 1980s, yet only for the ...

Charmed baryon weak decays with SU(3) flavor symmetry

We study the semileptonic and non-leptonic charmed baryon decays with SU(3) flavor symmetry, where the charmed baryons can be B c = (Ξ c 0 , Ξ c + , Λ c + ), B c ′ = (Σ c (++,+,0) , Ξ c ′ (+,0) , Ω c 0 ), B cc = (Ξ cc + + , Ξ cc + , Ω c + ) or B cc = Ω ccc + + . With B n (′) denoted as the baryon octet (decuplet), we find that the B c → B n ′ ℓ + ν ℓ decays are forbidden, while the ...

A swamp of non-SUSY vacua

We consider known examples of non-supersymmetric AdS7 and AdS4 solutions arising from compactifications of massive type IIA supergravity and study their stability, taking into account the coupling between closed- and open-string sector excitations. Generically, open strings are found to develop modes with masses below the Breitenlohner-Freedman (BF) bound. We comment on the ...

Zγ production at NNLO including anomalous couplings

In this paper we present a next-to-next-to-leading order (NNLO) QCD calculation of the processes pp → l + l −γ and \( pp\to \nu \overline{\nu}\gamma \) that we have implemented in MCFM. Our calculation includes QCD corrections at NNLO both for the Standard Model (SM) and additionally in the presence of Zγγ and ZZγ anomalous couplings. We compare our implementation, obtained using ...

Exotic matter on singular divisors in F-theory

We analyze exotic matter representations that arise on singular seven-brane configurations in F-theory. We develop a general framework for analyzing such representations, and work out explicit descriptions for models with matter in the 2-index and 3-index symmetric representations of SU(N) and SU(2) respectively, associated with double and triple point singularities in the ...

LHC Run I bounds on minimal lepton flavour violation in Type-III see-saw: a case study

In minimal lepton flavour violation Type-III see-saw models the flavour structure of the couplings of the triplet fermions to the Standard Model leptons can be reconstructed from the neutrino mass matrix and lepton number violation is very suppressed. Here, we explore the possibility of imposing bounds on this class of models with results of existing LHC searches and we quantify ...

Structure constants of operators on the Wilson loop from integrability

We study structure constants of local operators inserted on the Wilson loop in \( \mathcal{N}=4 \) super Yang-Mills theory. We conjecture the finite coupling expression of the structure constant which is interpreted as one hexagon with three mirror edges contracted by the boundary states. This is consistent with a holographic description of the correlator as the cubic open string ...

A proposal for (0,2) mirrors of toric varieties

In this paper we propose (0,2) mirrors for general Fano toric varieties with special tangent bundle deformations, corresponding to subsets of toric deformations. Our mirrors are of the form of (B/2-twisted) (0,2) Landau-Ginzburg models, matching Hori-Vafa mirrors on the (2,2) locus. We compare our predictions to (0,2) mirrors obtained by Chen et al. for certain examples of toric ...

Non-perturbative reheating and Nnaturalness

We study models in which reheating happens only through non-perturbative processes. The energy transferred can be exponentially suppressed unless the inflaton is coupled to a particle with a parametrically small mass. Additionally, in some models a light scalar with a negative mass squared parameter leads to much more efficient reheating than one with a positive mass squared of the ...

Complex Chern-Simons from M5-branes on the squashed three-sphere

We derive an equivalence between the (2,0) superconformal M5-brane field theory dimensionally reduced on a squashed three-sphere, and Chern-Simons theory with complex gauge group. In the reduction, the massless fermions obtain an action which is second order in derivatives and are reinterpreted as ghosts for gauge fixing the emergent non-compact gauge symmetry. A squashing ...

Superposition induced topology changes in quantum gravity

We show that superpositions of classical states in quantum gravity with fixed topology can lead to new classical states with a different topology. We study this phenomenon in a particular limit of the LLM geometries. In this limit, the UV complete minisuperspace of allowed quantum states is exactly given by the Hilbert space of a free chiral boson in two dimensions. We construct ...

Multilepton signals of heavier electroweakinos at the LHC

As a sequel to our recent paper we examine the phenomenology of the full electroweakino sector of the pMSSM without invoking the ad hoc but often employed assumption that the heavier ones are decoupled. We showcase the importance of the heavier electroweakinos using several generic models with different hierarchies among the slepton and electroweakino masses. We obtain constraints ...

E 8 orbits of IR dualities

We discuss USp(2n) supersymmetric models with eight fundamental fields and a field in the antisymmetric representation. Turning on the most generic superpotentials, coupling pairs of fundamental fields to powers of the antisymmetric field while preserving an R symmetry, we give evidence for the statement that the models are connected by a large network of dualities which can be ...

Continuous-spin field propagator and interaction with matter

Action principles for the single and double valued continuous-spin representations of the Poincaré group have been recently proposed in a Segal-like formulation. We address three related issues: first, we explain how to obtain these actions directly from the Fronsdal-like and Fang-Fronsdal-like equations by solving the traceless constraints in Fourier space. Second, we introduce a ...

Global orientifolded quivers with inflation

We describe global embeddings of fractional D3 branes at orientifolded singularities in type IIB flux compactifications. We present an explicit Calabi-Yau example where the chiral visible sector lives on a local orientifolded quiver while non-perturbative effects, α′ corrections and a T-brane hidden sector lead to full closed string moduli stabilisation in a de Sitter vacuum. The ...

Vacuum degeneracy and Conformal Mass in Lovelock AdS gravity

It is shown that the notion of Conformal Mass can be defined within a given anti-de Sitter (AdS) branch of a Lovelock gravity theory as long as the corresponding vacuum is not degenerate. Indeed, conserved charges obtained by the addition of Kounterterms to the bulk action turn out to be proportional to the electric part of the Weyl tensor, when the fall-off of a generic solution ...

Pauli-Lubanski limit and stress-energy tensor for infinite-spin fields

String-localized quantum fields transforming in Wigner’s infinite-spin representations were originally introduced in [18, 19]. We construct these fields as limits of fields of finite mass m → 0 and finite spin s → ∞. We determine a string-localized infinite-spin quantum stress-energy tensor with a novel prescription that does not refer to a classical Lagrangean.

Quiver theories and formulae for nilpotent orbits of Exceptional algebras

We treat the topic of the closures of the nilpotent orbits of the Lie algebras of Exceptional groups through their descriptions as moduli spaces, in terms of Hilbert series and the highest weight generating functions for their representation content. We extend the set of known Coulomb branch quiver theory constructions for Exceptional group minimal nilpotent orbits, or reduced ...

The μ-τ reflection symmetry of Dirac neutrinos and its breaking effect via quantum corrections

Given the Dirac neutrino mass term, we explore the constraint conditions which allow the corresponding mass matrix to be invariant under the μ-τ reflection transformation, leading us to the phenomenologically favored predictions θ 23 = π/4 and δ = 3π/2 in the standard parametrization of the 3 × 3 lepton flavor mixing matrix. If such a flavor symmetry is realized at a superhigh ...