Validation of harmonic-space likelihood methods for LiteBIRD B-mode polarisation analysis
Abstract
The LiteBIRD satellite mission aims to measure the tensor-to-scalar ratio r with unprecedented sensitivity through observations of the cosmic microwave background (CMB) B-mode polarisation. Robust constraints on r require accurate likelihood modelling across a wide range of angular scales. In this work, we validate harmonic-space likelihood methods against pixel-based benchmarks using 20\,000 end-to-end simulations that include CMB, instrumental noise, and Galactic foreground residuals processed through a realistic component-separation pipeline. We compare a debiased pixel-based likelihood, which serves as our benchmark on large scales (ℓ≤32), with an offset Hamimeche \& Lewis (oHL) likelihood applicable across the full multipole range. We systematically explore the space of analysis settings, identifying the number of simulations used for covariance estimation and the choice of beam window function as the most critical factors. Over the full multipole range considered (ℓ≤128), where the benchmark combines the pixel-based likelihood at ℓ≤32 with a harmonic one at smaller scales, the 68\% upper bound on r from the oHL likelihood is $19−−29\%$ larger than the benchmark one, depending on the beam window function. This demonstrates its viability as a computationally efficient baseline for LiteBIRD data analysis and cosmological inference from the polarisation B-mode field.
Related
- A cross-calibration approach for polarisation-sensitive detectors in CMB experiments: application to LiteBIRD's polarisation angle calibration
- Reconstruction of Shower-like Events in NEON Using Likelihood and Graph Neural Network Methods
- Setting requirements on out-of-band rejection for next-generation CMB experiments. Application to the LiteBIRD instrument
- Combining Systematic Effects in CMB Polarization Experiments through map-based simulations: application to LiteBIRD's HWP non-idealities and detectors non-linearity
- CMB Data Analysis in the example of the POLARBEAR experiment and the LiteBIRD experiment
BibTeX
@misc{galloni2026validation,
title = {{Validation of harmonic-space likelihood methods for LiteBIRD B-mode polarisation analysis}},
author = {G Galloni and P Campeti and C Gimeno-Amo and A Carones and A Rizzieri and Y Chinone and N Krachmalnicoff and E Martínez-González and L Pagano and D Adak and E Allys and A Anand and K Aryan and J Aumont and C Baccigalupi and A.J Banday and R.B Barreiro and N Bartolo and A Basyrov and M Bersanelli and A Besnard and F Bouchet and N Brancadori and T Brinckmann and F.J Casas and L. Castelló Gomar and L Colombo and F Columbro and A Coppolecchia and M Cruz and F Cuttaia and P de Bernardis and E de la Hoz and M de Lucia and S Della Torre and C Demay and P Diego-Palazuelos and J.J. Díaz García and F Finelli and C Franceschet and U Fuskeland and M Galloway and K Ganga and M Gerbino and T Ghigna and S Giardiello and E Gjerløw and M Gomes and A Gruppuso and S.E Harper and M Hazumi and S Henrot-Versillé and L.T Hergt and E Hivon and K Ikuma and H Ishino and K Kohri and L Lamagna and M Lattanzi and C Leloup},
howpublished = {HAL},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.18036},
eprint = {2610.18036},
archivePrefix = {arXiv},
url = {https://hal.science/hal-05842410v1},
}
RIS
TY - UNPB
TI - Validation of harmonic-space likelihood methods for LiteBIRD B-mode polarisation analysis
AU - G Galloni
AU - P Campeti
AU - C Gimeno-Amo
AU - A Carones
AU - A Rizzieri
AU - Y Chinone
AU - N Krachmalnicoff
AU - E Martínez-González
AU - L Pagano
AU - D Adak
AU - E Allys
AU - A Anand
AU - K Aryan
AU - J Aumont
AU - C Baccigalupi
AU - A.J Banday
AU - R.B Barreiro
AU - N Bartolo
AU - A Basyrov
AU - M Bersanelli
AU - A Besnard
AU - F Bouchet
AU - N Brancadori
AU - T Brinckmann
AU - F.J Casas
AU - L. Castelló Gomar
AU - L Colombo
AU - F Columbro
AU - A Coppolecchia
AU - M Cruz
AU - F Cuttaia
AU - P de Bernardis
AU - E de la Hoz
AU - M de Lucia
AU - S Della Torre
AU - C Demay
AU - P Diego-Palazuelos
AU - J.J. Díaz García
AU - F Finelli
AU - C Franceschet
AU - U Fuskeland
AU - M Galloway
AU - K Ganga
AU - M Gerbino
AU - T Ghigna
AU - S Giardiello
AU - E Gjerløw
AU - M Gomes
AU - A Gruppuso
AU - S.E Harper
AU - M Hazumi
AU - S Henrot-Versillé
AU - L.T Hergt
AU - E Hivon
AU - K Ikuma
AU - H Ishino
AU - K Kohri
AU - L Lamagna
AU - M Lattanzi
AU - C Leloup
PY - 2026
DA - 2026/10/13
PB - HAL
DO - 10.48550/arxiv.2610.18036
UR - https://hal.science/hal-05842410v1
AB - The LiteBIRD satellite mission aims to measure the tensor-to-scalar ratio r with unprecedented sensitivity through observations of the cosmic microwave background (CMB) B-mode polarisation. Robust constraints on r require accurate likelihood modelling across a wide range of angular scales. In this work, we validate harmonic-space likelihood methods against pixel-based benchmarks using 20\,000 end-to-end simulations that include CMB, instrumental noise, and Galactic foreground residuals processed through a realistic component-separation pipeline. We compare a debiased pixel-based likelihood, which serves as our benchmark on large scales (ℓ≤32), with an offset Hamimeche \& Lewis (oHL) likelihood applicable across the full multipole range. We systematically explore the space of analysis settings, identifying the number of simulations used for covariance estimation and the choice of beam window function as the most critical factors. Over the full multipole range considered (ℓ≤128), where the benchmark combines the pixel-based likelihood at ℓ≤32 with a harmonic one at smaller scales, the 68\% upper bound on r from the oHL likelihood is $19−−29\%$ larger than the benchmark one, depending on the beam window function. This demonstrates its viability as a computationally efficient baseline for LiteBIRD data analysis and cosmological inference from the polarisation B-mode field.
ER -