TY - JOUR
T1 - Missing large-angle correlations versus even-odd point-parity imbalance in the cosmic microwave background
AU - Sanchis-Lozano, M. A.
AU - Melia, F.
AU - López-Corredoira, M.
AU - Sanchis-Gual, N.
N1 - Funding Information:
Acknowledgements. This work has been partially supported by Agencia Estatal de Investigación del Ministerio de Ciencia e Innovación under grant PID2020-113334GB-I00/AEI/10.13039/501100011033, by Generalitat Valenciana under grant PROMETEO/2019/113 (EXPEDITE), by the Center for Research and Development in Mathematics and Applications (CIDMA) through the Portuguese Foundation for Science and Technology (FCT – Fundação para a Ciên-cia e a Tecnologia), references UIDB/04106/2020 and UIDP/04106/2020, by national funds (OE), through FCT, I.P., in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19 and by the projects PTDC/FIS-OUT/28407/2017, CERN/FIS-PAR/0027/2019 and PTDC/FIS-AST/3041/2020. This work has further been supported by the European Union’s Horizon 2020 research and innovation (RISE) programme H2020-MSCA-RISE-2017 Grant No. FunFiCO-777740 and by FCT through Project No. UIDB/00099/2020.
Publisher Copyright:
© 2022 ESO.
PY - 2022/4/1
Y1 - 2022/4/1
N2 - Context. The existence of a maximum correlation angle (θmax≲; 60) in the two-point angular temperature correlations of cosmic microwave background (CMB) radiation, measured by WMAP and Planck, stands in sharp contrast to the prediction of standard inflationary cosmology, in which the correlations should extend across the full sky (i.e., 180). The introduction of a hard lower cutoff (kmin) in the primordial power spectrum, however, leads naturally to the existence of θmax. Among other cosmological anomalies detected in these data, an apparent dominance of odd-over-even parity multipoles has been seen in the angular power spectrum of the CMB. This feature, however, may simply be due to observational contamination in certain regions of the sky. Aims. In attempting to provide a more detailed assessment of whether this odd-over-even asymmetry is intrinsic to the CMB, we therefore proceed in this paper, first, to examine whether this odd-even parity imbalance also manifests itself in the angular correlation function and, second, to examine in detail the interplay between the presence of θmax and this observed anomaly. Methods. We employed several parity statistics and recalculated the angular correlation function for different values of the cutoff kmin in order to optimize the fit to the different Planck 2018 data. Results. We find a phenomenological connection between these features in the data, concluding that both must be considered together in order to optimize the theoretical fit to the Planck 2018 data. Conclusions. This outcome is independent of whether the parity imbalance is intrinsic to the CMB, but if it is, the odd-over-even asymmetry would clearly point to the emergence of new physics.
AB - Context. The existence of a maximum correlation angle (θmax≲; 60) in the two-point angular temperature correlations of cosmic microwave background (CMB) radiation, measured by WMAP and Planck, stands in sharp contrast to the prediction of standard inflationary cosmology, in which the correlations should extend across the full sky (i.e., 180). The introduction of a hard lower cutoff (kmin) in the primordial power spectrum, however, leads naturally to the existence of θmax. Among other cosmological anomalies detected in these data, an apparent dominance of odd-over-even parity multipoles has been seen in the angular power spectrum of the CMB. This feature, however, may simply be due to observational contamination in certain regions of the sky. Aims. In attempting to provide a more detailed assessment of whether this odd-over-even asymmetry is intrinsic to the CMB, we therefore proceed in this paper, first, to examine whether this odd-even parity imbalance also manifests itself in the angular correlation function and, second, to examine in detail the interplay between the presence of θmax and this observed anomaly. Methods. We employed several parity statistics and recalculated the angular correlation function for different values of the cutoff kmin in order to optimize the fit to the different Planck 2018 data. Results. We find a phenomenological connection between these features in the data, concluding that both must be considered together in order to optimize the theoretical fit to the Planck 2018 data. Conclusions. This outcome is independent of whether the parity imbalance is intrinsic to the CMB, but if it is, the odd-over-even asymmetry would clearly point to the emergence of new physics.
KW - Cosmic background radiation
KW - Cosmological parameters
KW - Cosmology: observations
KW - Cosmology: theory
KW - Inflation
KW - Large-scale structure of Universe
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U2 - 10.1051/0004-6361/202142296
DO - 10.1051/0004-6361/202142296
M3 - Article
AN - SCOPUS:85129140288
VL - 660
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
SN - 0004-6361
M1 - A121
ER -