29 research outputs found

    The Infrared Structure of Exceptional Scalar Theories

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    Exceptional theories are a group of one-parameter scalar field theories with (enhanced) vanishing soft limits in the S-matrix elements. They include the nonlinear sigma model (NLSM), Dirac-Born-Infeld scalars and the special Galileon theory. The soft behavior results from the shift symmetry underlying these theories, which leads to Ward identities generating subleading single soft theorems as well as novel Berends-Giele recursion relations. Such an approach was first applied to NLSM in 1709.08639 and 1804.08629, and here we use it to systematically study other exceptional scalar field theories. In particular, using the subleading single soft theorem for the special Galileon we identify the Feynman vertices of the corresponding extended theory, which was first discovered using the Cachazo-He-Yuan representation of scattering amplitudes. Furthermore, we present a Lagrangian for the extended theory of the special Galileon, which has a rich particle content involving biadjoint scalars, Nambu-Goldstone bosons and Galileons, as well as additional flavor structure.Comment: 30 pages + appendices, 7 figures; matched to the JHEP version in v

    Ward Identity and Scattering Amplitudes for Nonlinear Sigma Models

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    We present a Ward identity for nonlinear sigma models using generalized nonlinear shift symmetries, without introducing current algebra or coset space. The Ward identity constrains correlation functions of the sigma model such that the Adler's zero is guaranteed for SS-matrix elements, and gives rise to a subleading single soft theorem that is valid at the quantum level and to all orders in the Goldstone decay constant. For tree amplitudes, the Ward identity leads to a novel Berends-Giele recursion relation as well as an explicit form of the subleading single soft factor. Furthermore, interactions of the cubic biadjoint scalar theory associated with the single soft limit, which was previously discovered using the Cachazo-He-Yuan representation of tree amplitudes, can be seen to emerge from matrix elements of conserved currents corresponding to the generalized shift symmetry.Comment: 5 page

    Universal Relations in Composite Higgs Models

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    We initiate a phenomenological study of `universal relations' in composite Higgs models, which are dictated by nonlinear shift symmetries acting on the 125 GeV Higgs boson. These are relations among one Higgs couplings with two electroweak gauge bosons (HVV), two Higgses couplings with two electroweak gauge bosons (HHVV), one Higgs couplings with three electroweak gauge bosons (HVVV), as well as triple gauge boson couplings (TGC), which are all controlled by a single input parameter: the decay constant ff of the pseudo-Nambu-Goldstone Higgs boson. Assuming custodial invariance in strong sector, the relation is independent of the symmetry breaking pattern in the UV, for an arbitrary symmetric coset G/HG/H. The complete list of corrections to HVV, HHVV, HVVV and TGC couplings in composite Higgs models is presented to all orders in 1/f1/f, and up to four-derivative level, without referring to a particular G/HG/H. We then present several examples of universal relations in ratios of coefficients which could be extracted experimentally. Measuring the universal relation requires a precision sensitive to effects of dimension-8 operators in the effective Lagrangian and highlights the importance of verifying the tensor structure of HHVV interactions in the standard model, which remains untested to date.Comment: 31 pages, 6 figure

    Universal Imprints of a Pseudo-Nambu-Goldstone Higgs Boson

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    A large class of models addressing the electroweak naturalness problem postulates the existence of new spontaneously broken global symmetries above the weak scale. The Higgs boson arises as a pseudo-Nambu-Goldstone boson (pNGB) whose interactions are nonlinear due to the presence of de- generate vacua. We argue that, once the normalization of the pNGB decay constant f is determined, the Higgs nonlinear interactions in the gauge sector are universal in the infrared and independent of the symmetry breaking pattern G/H, even after integrating out heavy composite resonances. We propose a set of "universal relations" in Higgs couplings with electroweak gauge bosons and in triple gauge boson couplings, which are unique predictions of the universal nonlinearity. Experimental measurements of these relations would serve as the litmus test of a pNGB Higgs boson.Comment: 5 page

    Completing the Fifth PN Precision Frontier via the EFT of Spinning Gravitating Objects

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    We derive and establish the new precision frontier at the fifth PN (5PN) order, and put forward a broader picture of the effective theory of a spinning particle within the EFT of spinning gravitating objects. This precision frontier includes higher-spin sectors, quadratic and quartic in the spin, which both display novel physical effects, from the extension of the effective theory beyond linear order in the curvature. In the quadratic-in-spin sectors there is a new tidal effect, and in the quartic-in-spin sectors there is a new multipolar deformation. With eyes towards the next precision frontier, we then generalize the concept of tidal operators and of spin-induced multipolar deformations, and make conjectures on the numerical values of their Wilson coefficients for Kerr black holes. We confirm the generalized actions for generic compact objects of the NLO quartic-in-spin sectors which were derived via the extension of the EFT of gravitating spinning objects. We derive the consequent interaction potentials and general Hamiltonians, that consist of 12 distinct sectors, with a new one due to the new multipolar deformation. These Hamiltonians give the full information on the binary system, which partly gets lost, especially in higher-spin sectors, when going to observables with aligned-spins, since generic spin orientations have an observational signature in the gravitational waveform. Moreover with these Hamiltonians, obtained within our framework, we find the complete Poincar\'e algebra at the 5PN order with spins. We derive observables for GW applications, and to further make contact with the scattering problem, we also derive the extrapolated scattering angles with aligned spins. The completion of the Poincar\'e algebra provides the strongest validation to our most comprehensive new results, and thus that the 5PN order has now been established as the new precision frontier.Comment: 51 p

    Rethinking Urban Flood Risk Assessment By Adapting Health Domain Perspective

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    Inspired by ideas from health risk assessment, this paper presents a new perspective for flood risk assessment. The proposed perspective focuses on three pillars for examining flood risk: (1) inherent susceptibility, (2) mitigation strategies, and (3) external stressors. These pillars collectively encompass the physical and environmental characteristics of urban areas, the effectiveness of human-intervention measures, and the influence of uncontrollable external factors, offering a fresh point of view for decoding flood risks. For each pillar, we delineate its individual contributions to flood risk and illustrate their interactive and overall impact. The three-pillars model embodies a shift in focus from the quest to precisely model and quantify flood risk to evaluating pathways to high flood risk. The shift in perspective is intended to alleviate the quest for quantifying and predicting flood risk at fine resolutions as a panacea for enhanced flood risk management. The decomposition of flood risk pathways into the three intertwined pillars (i.e., inherent factors, mitigation factors, and external factors) enables evaluation of changes in factors within each pillar enhance and exacerbate flood risk, creating a platform from which to inform plans, decisions, and actions. Building on this foundation, we argue that a flood risk pathway analysis approach, which examines the individual and collective impacts of inherent factors, mitigation strategies, and external stressors, is essential for a nuanced evaluation of flood risk. Accordingly, the proposed perspective could complement the existing frameworks and approaches for flood risk assessment

    N3^3LO Spin-Orbit Interaction via the EFT of Spinning Gravitating Objects

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    We present the derivation of the third subleading order (N3^3LO) spin-orbit interaction at the state of the art of post-Newtonian (PN) gravity via the EFT of spinning objects. The present sector contains the largest and most elaborate collection of Feynman graphs ever tackled to date in sectors with spin, and in all PN sectors up to third subleading order. Our computations are carried out via advanced multi-loop methods. Their most demanding aspect is the imperative transition to a generic dimension across the whole derivation, due to the emergence of dimensional-regularization poles across all loop orders as of the N3^3LO sectors. At this high order of sectors with spin, it is also critical to extend the formal procedure for the reduction of higher-order time derivatives of spin variables beyond linear order for the first time. This gives rise to a new unique contribution at the present sector. The full interaction potential in Lagrangian form and the general Hamiltonian are provided here for the first time. The consequent gravitational-wave (GW) gauge-invariant observables are also derived, including relations among the binding energy, angular momentum, and emitted frequency. Complete agreement is found between our results, and the binding energy of GW sources, and also with the extrapolated scattering angle in the scattering problem, derived via traditional GR. In contrast with the latter derivation, our framework is free-standing and generic, and has provided theory and results, which have been critical to establish the state of the art, and to push the precision frontier for the measurement of GWs.Comment: 65 pp, 21 ancillary files, including 386pp pdf of visual graph

    N3^3LO Quadratic-in-Spin Interactions for Generic Compact Binaries

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    We derive the third subleading (N3^3LO) corrections in the quadratic-in-spin sectors via the EFT of spinning objects in post-Newtonian (PN) gravity. These corrections include contributions from 4 sectors for generic compact objects, entering at the fifth PN order. One of these is a new tidal interaction, first entering in the spinning sectors, which complements the tidal interaction that first enters at the same PN order in the non-spinning sector. The evaluation of Feynman graphs is carried out in a generic dimension via multi-loop methods, and yields dimensional-regularization poles in conjunction with logarithms. At these higher-spin sectors the reduction of generalized Lagrangians entails redefinitions of the position beyond linear order. We provide here for the first time the relevant Lagrangians and Hamiltonians, and their useful simplified versions. We also derive the consequent gauge-invariant binding energy relations to the angular momentum and frequency. We end with a derivation of all scattering angles for aligned spins that correspond to an extension of the Hamiltonians for binary inspirals of the 44 independent sectors, and find complete agreement with the limited available results obtained via traditional GR, EFT and scattering-amplitudes methods.Comment: 55 pp, 1 figure, 25 ancillary files, including pdf of ~1000 visual graph
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