The Orthogonal Non-Gaussian Shape at a Bounce and Its Correlation With the Standard Template
Year: 2026
Type: article
Abstract: Data analyses search for primordial non-Gaussianity with a small set of standard templates, so a model's bispectrum matters observationally only through its overlap with those templates. This paper computes the overlap of the bounce-generated bispectrum with the orthogonal template and the amplitude the orthogonal search would report. The normalised shape correlation, evaluated as an inner-product integral over the reduced triangle domain, is 0.753, leaving a fraction 0.433 of the bounce bispectrum's power outside the orthogonal template. Projected onto that template, the model predicts fNL orthogonal = -21, against the Planck 2018 measurement of -38 plus or minus 24, a deviation of 0.71 standard deviations. The bounce bispectrum is thus substantially, but far from entirely, visible to the standard orthogonal search: more than two fifths of its signal power would be missed by template analyses, a correction that matters when null results are converted into bounds on bounce parameters. The study is computed from stated assumptions, not measured.
Author: Aldred, William Alexander
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7225828629
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