TY  - JOUR
AU  - Sanchis-Lozano, M. A.
AU  - Sanz, V.
PY  - 2024
DA  - 2024//
TI  - Observable imprints of primordial gravitational waves on the temperature anisotropies of the cosmic microwave background
T2  - Phys. Rev. D
JO  - Physical Review D
SP  - 063529
EP  - 11pp
VL  - 109
IS  - 6
PB  - Amer Physical Soc
AB  - We examine the contribution of tensor modes, in addition to the dominant scalar ones, on the temperature anisotropies of the cosmic microwave background (CMB). To this end, we analyze in detail the temperature two -point angular correlation function C(Theta) from the Planck 2018 dataset, focusing on large angles (Theta greater than or similar to 120 degrees) corresponding to small l multipoles. A hierarchical set of infrared cutoffs are naturally introduced to the scalar and tensor power spectra of the CMB by invoking an extra Kaluza-Klein spatial dimension compactifying at about the grand unified theory scale between the Planck epoch and the start of inflation. We associate this set of lower scalar and tensor cutoffs with the parity of the multipole expansion of the C(Theta) function. By fitting the Planck 2018 data we compute the multipole coefficients, thereby reproducing the well-known odd -parity preference in angular correlations seen by all three satellite missions: Cosmic Background Explorer, WMAP, and Planck. Our fits improve significantly once tensor modes are included in the analysis, hence providing a hint of the imprints of primordial gravitational waves on the temperature correlations observed in the CMB today. To conclude, we suggest a relationship between, on the one hand, the lack of (positive) large -angle correlations and the odd -parity dominance in the CMB and, on the other hand, the effect of primordial gravitational waves on the CMB temperature anisotropies.
SN  - 2470-0010
UR  - https://arxiv.org/abs/2312.02740
UR  - https://doi.org/10.1103/PhysRevD.109.063529
DO  - 10.1103/PhysRevD.109.063529
LA  - English
N1  - WOS:001195716600006
ID  - Sanchis-Lozano+Sanz2024
ER  -