Cutting Rule for Cosmological Collider Signals: A Bulk Evolution Perspective

Tong, Xi; Wang, Yi; Zhu, Yuhang

doi:10.48550/arxiv.2112.03448

Cited by 2 publications

(2 citation statements)

References 43 publications

(49 reference statements)

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“…which emphasizes that this structure is representative of the underlying cutting rules applied to Fig. 1 [99]. We point out that the overbar in Ī(1) h indicates complex conjugation.…”

Section: A General Calculationmentioning

confidence: 67%

Parity-Violating Trispectrum from Chern-Simons Gravity

Creque-Sarbinowski¹,

Alexander²,

Kamionkowski³

et al. 2023

Preprint

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A potential source for parity violation in the Universe is inflation. The simplest inflationary models have two fields: the inflaton and graviton, and the lowest-order parity-violating coupling between them is dynamical Chern-Simons (dCS) gravity with a decay constant f . Here, we show that dCS imprints a parity-violating signal in primordial scalar perturbations. Specifically, we find that, after dCS amplifies one graviton helicity due to a tachyonic instability, the graviton-mediated correlation between two pairs of scalars develops a parity-odd component. This correlation, the primordial scalar trispectrum, is then transferred to the corresponding curvature correlator and thus is imprinted in both large-scale structure (LSS) and the cosmic microwave background (CMB). We find that the parity-odd piece has roughly the same amplitude as its parity-even counterpart, scaled linearly by the degree of gravitational circular polarization Πcirc ∼ √ ε[H 2 /(M Pl f )] ≤ 1, with ε the slow-roll parameter, H the inflationary Hubble scale, and the upper bound saturated for purely circularlypolarized gravitons. We also find that, in the collapsed limit, the ratio of the two trispectra contains direct information about the graviton's spin. In models beyond standard inflationary dCS, e.g. those with multiple scalar fields or superluminal scalar sound speed, there can be a large enhancement factor F 10 6 to the trispectrum. We find that an LSS survey that contains N modes linear modes would place an nσ constraint on Πcircr of ∼ 0.04 (n/3)(10 6 /F )(10 6 /N modes ) 1/2 from the parity-odd galaxy trispectrum, for tensor-to-scalar ratio r. We also forecast for several spectroscopic and 21-cm surveys. This constraint implies that, for high-scale single-field inflation parameters, LSS can probe very large dCS decay constants f 4 × 10 9 GeV(3/n)(F/10 6 ) N modes /10 6 1/2 . Our result is the first example of a massless particle yielding a parity-odd scalar trispectrum through spin-exchange.

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“…which emphasizes that this structure is representative of the underlying cutting rules applied to Fig. 1 [99]. We point out that the overbar in Ī(1) h indicates complex conjugation.…”

Section: A General Calculationmentioning

confidence: 67%

Parity-Violating Trispectrum from Chern-Simons Gravity

Creque-Sarbinowski¹,

Alexander²,

Kamionkowski³

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…The general recursion formula is given in equation (4.14), and is obtained by deforming the kinematics that the wavefunction depends on into the complex plane. The recursion relations as a sort of cosmological collider [23,34,35,[46][47][48][49][50][51][52][53][54][55][56][57]. 2 Scattering amplitudes can also satisfy soft theorems when there are cubic vertices present that are compatible with the nonlinearly realized symmetries, for example in the conformal dilaton [61], or in non-relativistic cases [62] (see also [63] for another relativistic example).…”

Section: Introductionmentioning

confidence: 99%

Soft limits of the wavefunction in exceptional scalar theories

Noah¹,

Joyce²

2022

Preprint

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We study the structure of the flat space wavefunctional in scalar field theories with nonlinearly realized symmetries. These symmetries imply soft theorems that are satisfied by wavefunction coefficients in the limit where one of the external momenta is scaled to zero. After elucidating the structure of these soft theorems in the nonlinear sigma model, Dirac-Born-Infeld, and galileon scalar theories, we combine them with information about the singularity structure of the wavefunction to bootstrap the wavefunction coefficients of these theories. We further systematize this construction through two types of recursion relations: one that utilizes the flat space scattering amplitude plus minimal information about soft limits, and an alternative that does not require amplitude input, but does require subleading soft information.

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Cutting Rule for Cosmological Collider Signals: A Bulk Evolution Perspective

Cited by 2 publications

References 43 publications

Parity-Violating Trispectrum from Chern-Simons Gravity

Parity-Violating Trispectrum from Chern-Simons Gravity

Soft limits of the wavefunction in exceptional scalar theories

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