Journal of High Energy Physics最新文献

There is now strong evidence that the superconformal index of holographic gauge theories admits a giant graviton expansion capturing the worldvolume dynamics of spherical D3-branes moving in internal space. While the giant graviton indices may be written as suitable contour integrals, care must be taken in their evaluation, as there can be an ambiguity in choice of integration contour or, equivalently, “pole selection”. We resolve this ambiguity by using Murthy’s recent expansion of the superconformal index to provide a rigorous underpinning of the evaluation of the supergravity giant graviton indices. In doing so, we directly relate Murthy’s giant graviton expansion to the supergravity D3-brane expansion.

We apply our previously developed approach to marginal quartic interactions in multiscalar QFTs, which shows that one-loop RG flows can be described in terms of a commutative algebra, to various models in 4d. We show how the algebra can be used to identify optimal scalings of the couplings for taking large N limits. The algebra identifies these limits without diagrammatic or combinatorial analysis. For several models this approach leads to new limits yet to be explored at higher loop orders. We consider the bifundamental and trifundamental models, as well as a matrix-vector model with an adjoint representation. Among the suggested new limit theories are some which appear to be less complex than general planar limits but more complex than ordinary vector models or melonic models.

We study a texture of neutrino mass matrix characterized by two constraints consisting of one equality and another antiequality between two elements corresponding to two pairs of the matrix entries. Amidst such textures, we limit our study to three patterns which were realizable assuming an S₄-symmetry within type II-seesaw scenario. Three such cases were found and studied: I (M_ν22 = −M_ν33 & M_ν11 = +M_ν23), II (M_ν11 = −M_ν33 & M_ν22 = +M_ν13) and III (M_ν11 = −M_ν22 & M_ν33 = +M_ν12). We specify the role of unphysical phases in the definition of the textures under study which were tested against experimental constraints, and were found to accommodate data with both hierarchies allowed. However, switching off the unphysical phases allows only for inverted hierarchy, except for the texture III which allows also, albeit for a very narrow parameter space region, for normal ordering. We stress that the different phenomenologies when including/excluding unphysical phases stem from the different definitions of the texture one has to adopt in order to make it insensitive to unphysical phases, rather than to any ‘absent’ physical effects of unphysical phases. In addition, we made clear how a texture definition should be independent of the PMNS parametrization. We present a complete phenomenological analysis of these three textures and justify analytically the resulting correlations. We detail the effect of the unphysical phases in diluting/deforming several correlations, which otherwise would have been “clear”. Finally, we give theoretical realizations within seesaw type II scenarios for such textures.

Recently, the maximally-helicity-violating four-point form factor for the chiral stress-energy tensor in planar ( mathcal{N} ) = 4 super Yang-Mills was computed to three loops at the level of the symbol associated with multiple polylogarithms. It exhibits antipodal self-duality, or invariance under the combined action of a kinematic map and reversing the ordering of letters in the symbol. Here we lift the two-loop form factor from symbol level to function level. We provide an iterated representation of the function’s derivatives (coproducts). In order to do so, we find a three-parameter limit of the five-parameter phase space where the symbol’s letters are all rational. We also use function-level information about dihedral symmetries and the soft, collinear, and factorization limits, as well as limits governed by the form-factor operator product expansion (FFOPE). We provide plots of the remainder function on several kinematic slices, and show that the result is compatible with the FFOPE data. We further verify that antipodal self-duality is valid at two loops beyond the level of the symbol.

This study deals with a piecewise ϕ² scalar field theory in (1 + 1) dimensions. The scalar field potential is designed with a triple-well shape, engendering kink solutions with asymmetric square-well linearized potentials. Thus, the localized and delocalized modes in this model can be obtained analytically in terms of transcendental equations. This allows us to explore kink-antikink and antikink-kink collisions with any desired number of localized and delocalized modes. We obtain new scenarios of resonance windows suppression, shedding light on the role of higher excited modes in kink scattering.

We study the cohomology of an elliptic differential complex arising from the infinitesimal moduli of heterotic string theory in the supergravity approximation. We compute these cohomology groups at the standard embedding, and show that they decompose into a direct sum of cohomologies. While this is often assumed in the literature, it had not been explicitly demonstrated. Given a stable gauge bundle over a complex threefold with trivial canonical bundle and no holomorphic vector fields, we also show that the Euler characteristic of this differential complex is zero. This points towards a perfect obstruction theory for the heterotic moduli problem, at least for the most physically relevant compactifications.

We study the phenomenology of a string bosenova explosion in vector superradiance clouds around spinning black holes, focusing on the observable consequences in gravitational wave detectors and accelerometers. During the superradiance growth of a dark photon cloud — which occurs for dark photon masses ( {m}_{A^{prime }}sim {10}^{-14}-{10}^{-11}textrm{eV} ) around stellar-mass black holes (( {m}_{A^{prime }}sim {10}^{-23}-{10}^{-16}textrm{eV} ) for supermassive black holes) — the dark electromagnetic field might reach a critical field strength, when a network of dark photon strings is produced via a superheated phase transition. These dark photon strings will then absorb the energy in the background gauge fields and get ejected from the cloud, with total energy of the string network as large as the total rotational energy of the spinning black hole. In this paper, we study the subsequent evolution of this dense string network, and the resulting observational consequences depending on the unknown string tension, or almost equivalently, the ratio between the quartic and the gauge coupling in the Abelian Higgs model. Strings with large tension will dissipate into gravitational waves, detectable over a wide range of frequencies, from ~ nHz near supermassive blackholes, to ≳ 10MHz around stellar mass black holes. This is the first known source of high frequency gravitational waves, unconstrained by cosmological observations. The strain of this gravitational wave can be larger than 10⁻¹⁴ at low frequencies, lasting for longer than typical duration of experiments. Small tension strings, whose string networks can have total lengths as large as 10⁴⁰ km, can travel to the earth with appreciable rate from any black hole in the Milky Way and interact with earth based accelerometers. If the Standard Model particles are directly charged under the dark photon, e.g. U(1)_B−L, this interaction leads to an acceleration of Standard Model particles that is independent of the coupling strength. We work out the spectral density of this acceleration, and project that modern accelerometers and equivalence principle tests can be sensitive to the passing of these strings.

We propose bulk 3D ( mathcal{N} ) = 4 rank-0 superconformal field theories, which are related to 2D ( mathcal{N} ) = 1 supersymmetric minimal models, SM (2, ·) and SM (3, ·), via recently discovered non-unitary bulk-boundary correspondence. The correspondence relates a 3D ( mathcal{N} ) = 4 rank-0 superconformal field theory to 2D chiral rational conformal field theories. A topologically twisted theory of the rank-0 SCFT supports the rational chiral algebra at the boundary upon a proper choice of boundary condition. We test the proposal by checking several non-trivial dictionaries of the correspondence.

Inspired by the anomalies in ( Bto {D}^{left(ast right)}tau {overline{nu}}_{tau } ) decay, in this work, we carefully study the influence of the most general dimension-six effective operators involving right-handed neutrinos on the four cascade decays ( {B}_cto tau left(to {nu}_{tau }hright){overline{nu}}_{tau } ) (h = π, ρ) and ( {B}_cto tau left(to {nu}_{tau}ell {overline{nu}}_{ell}right){overline{nu}}_{tau } ) (ℓ = μ, e). We calculate for the first time the analytical results of the distributions of the differential decay rates of these cascade decays with respect to the energy of the charged particles in the final state. We select a total of 13 new physics benchmark points, among which 9 are derived from the effect of purely left-handed neutrinos, and the other 4 are from the effect of purely right-handed neutrinos. We find that the benchmark points BP4, BP6, BP11, and BP13 can significantly increase the values of these distributions while the BP3 causes a sharp decrease in these distributions. The end-point behavior of the differential distribution dΓ/dE_π can be used to disentangle the effects of left-handed and right-handed neutrinos. Finally, in order to eliminate the uncertainties brought by the CKM matrix element V_cb and the decay constant ( {f}_{B_c} ), we introduce the normalized distributions dΓ/(ΓdE_a) (a = π, ρ, μ, e), which are only sensitive to the right-handed neutrinos. We find that in each normalized distribution there exists a fixed point that is not related to any dimension-six effective operators considered in this work.

In this paper we discuss the definition, the construction and the implementation of generalised antenna functions for final-state radiation up to Next-to-Next-to-Leading Order (NNLO) in QCD. Generalised antenna functions encapsulate the singular behaviour of unresolved emissions when these occur within multiple hard radiators and not just two of them, as for traditional antenna functions. The construction of such objects is possible thanks to the recently proposed algorithm for building idealised antenna functions from a target set of infrared limits. Generalised antenna functions bring major simplifications in the assemblage of subtraction terms in the context of the antenna scheme at NNLO and beyond, as well as a substantial computational speedup of higher-order calculations. We discuss in detail the improvements on the formal and practical side for the computation of the NNLO correction to three-jet production at electron-positron colliders, providing a thorough numerical validation of the newly proposed scheme. For this calculation one can expect almost an order of magnitude speedup with respect to the original implementation.