LiteBIRD Science Goals and Forecasts. $E$-mode Anomalies
Abstract
Various so-called anomalies have been found in both the WMAP and Planck cosmic microwave background (CMB) temperature data that exert a mild tension against the highly successful best-fit 6 parameter cosmological model, potentially providing hints of new physics to be explored. That these are real features on the sky is uncontested. However, given their modest significance, whether they are indicative of true departures from the standard cosmology or simply statistical excursions, due to a mildly unusual configuration of temperature anisotropies on the sky which we refer to as the "fluke hypothesis", cannot be addressed further without new information. No theoretical model of primordial perturbations has to date been constructed that can explain all of the temperature anomalies. Therefore, we focus in this paper on testing the fluke hypothesis, based on the partial correlation between the temperature and -mode CMB polarisation signal. In particular, we compare the properties of specific statistics in polarisation, built from unconstrained realisations of the CDM cosmological model as might be observed by the LiteBIRD satellite, with those determined from constrained simulations, where the part of the -mode anisotropy correlated with temperature is constrained by observations of the latter. Specifically, we use inpainted Planck 2018 SMICA temperature data to constrain the -mode realisations. Subsequent analysis makes use of masks defined to minimise the impact of the inpainting procedure on the -mode map statistics. We find that statistical assessments of the -mode data alone do not provide any evidence for or against the fluke hypothesis. However, tests based on cross-statistical measures determined from temperature and modes can allow this hypothesis to be rejected with a moderate level of probability.
Cite
@article{arxiv.2508.16451,
title = {LiteBIRD Science Goals and Forecasts. $E$-mode Anomalies},
author = {A. J. Banday and C. Gimeno-Amo and P. Diego-Palazuelos and E. de la Hoz and A. Gruppuso and N. Raffuzzi and E. Martínez-González and P. Vielva and R. B. Barreiro and M. Bortolami and C. Chiocchetta and G. Galloni and D. Scott and R. M. Sullivan and D. Adak and E. Allys and A. Anand and J. Aumont and C. Baccigalupi and M. Ballardini and N. Bartolo and S. Basak and M. Bersanelli and A. Besnard and D. Blinov and F. Bouchet and T. Brinckmann and F. Cacciotti and E. Calabrese and P. Campeti and A. Carones and F. J. Casas and K. Cheung and M. Citran and L. Clermont and F. Columbro and A. Coppolecchia and P. de Bernardis and M. De Lucia and S. Della Torre and E. Di Giorgi and H. K. Eriksen and F. Finelli and C. Franceschet and U. Fuskeland and M. Galloway and M. Gervasi and R. T. Génova-Santos and T. Ghigna and S. Giardiello and M. Hazumi and L. T. Hergt and E. Hivon and K. Ichiki and H. Ishino and B. Jost and K. Kohri and L. Lamagna and M. Lattanzi and C. Leloup and F. Levrier and A. I. Lonappan and M. López-Caniego and G. Luzzi and J. Macias-Perez and V. Maranchery and S. Masi and S. Matarrese and T. Matsumura and S. Micheli and M. Migliaccio and M. Monelli and L. Montier and G. Morgante and M. Najafi and T. Namikawa and A. Novelli and I. Obata and A. Occhiuzzi and A. Paiella and D. Paoletti and G. Pascual-Cisneros and F. Piacentini and G. Piccirilli and G. Polenta and L. Porcelli and M. Remazeilles and A. Rizzieri and J. A. Rubiño-Martín and M. Ruiz-Granda and Y. Sakurai and J. Sanghavi and M. Shiraishi and G. Signorelli and Y. Takase and L. Terenzi and M. Tomasi and M. Tristram and L. Vacher and B. van Tent and I. K. Wehus and G. Weymann-Despres and E. J. Wollack and Y. Zhou},
journal= {arXiv preprint arXiv:2508.16451},
year = {2025}
}
Comments
39 pages, 23 figures. Prepared for submission to JCAP