29 research outputs found
The Infrared Structure of Exceptional Scalar Theories
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
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 -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
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 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 . The complete list of corrections to
HVV, HHVV, HVVV and TGC couplings in composite Higgs models is presented to all
orders in , and up to four-derivative level, without referring to a
particular . 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
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
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
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
NLO Spin-Orbit Interaction via the EFT of Spinning Gravitating Objects
We present the derivation of the third subleading order (NLO) 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
NLO 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
NLO Quadratic-in-Spin Interactions for Generic Compact Binaries
We derive the third subleading (NLO) 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 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