Constraints on multifield inflation from the BOSS galaxy survey

We use redshift-space galaxy clustering data from the BOSS survey to constrain local primordial non-Gaussianity (LPNG). This is of particular importance due to the consistency relations, which imply that a detection of LPNG would rule out all single-field inflationary models. Our constraints are based on the consistently analyzed redshift-space galaxy power spectra and bispectra, extracted from the public BOSS data with optimal window-free estimators. We use a complete perturbation theory model including all one-loop power spectrum corrections generated by LPNG. Our constraint on the amplitude of the local non-Gaussian shape is <math display="inline"><msubsup><mi>f</mi><mrow><mi>NL</mi></mrow><mtext>local</mtext></msubsup><mo>=</mo><mo>-</mo><mn>33</mn><mo>±</mo><mn>28</mn></math> at 68% C.L., yielding no evidence for primordial non-Gaussianity. The addition of the bispectrum tightens the <math display="inline"><msubsup><mi>f</mi><mrow><mi>NL</mi></mrow><mtext>local</mtext></msubsup></math> constraints from BOSS by 20%, and allows breaking of degeneracies with non-Gaussian galaxy bias. These results set the stage for the analysis of future surveys, whose larger volumes will yield significantly tighter constraints on LPNG.