A Measurement of the Cosmic Microwave Background B-mode Polarization Power Spectrum at Subdegree Scales from Two Years of polarbear Data
Ade, P. A. R.; Baccigalupi, C.; Borrill, J.; Ducout, A.; Jaffe, A. H.; Keskitalo, R.; Le Jeune, M.; Stompor, R.; Linder, E.; Chapman, S.; Reichardt, C. L.; Lee, A. T.; Leitch, E. M.; Tucker, C.; Dobbs, M.; Richards, P. L.; Kisner, T.; Krachmalnicoff, N.; Errard, J.; Teply, G. P.; Inoue, Y.; Gilbert, A.; Whitehorn, N.; Montgomery, J.; POLARBEAR Collaboration; Aguilar, M.; Akiba, Y.; Arnold, K.; Barron, D.; Beck, D.; Bianchini, F.; Boettger, D.; Chinone, Y.; Crowley, K.; Cukierman, A.; Dünner, R.; Elleflot, T.; Fabbian, G.; Feeney, S. M.; Feng, C.; Fujino, T.; Galitzki, N.; Goeckner-Wald, N.; Groh, J. C.; Hall, G.; Halverson, N.; Hamada, T.; Hasegawa, M.; Hazumi, M.; Hill, C. A.; Howe, L.; Jaehnig, G.; Jeong, O.; Kaneko, D.; Katayama, N.; Keating, B.; Kusaka, A.; Leon, D.; Lowry, L.; Matsuda, F.; Matsumura, T.; Minami, Y.; Navaroli, M.; Nishino, H.; Paar, H.; Peloton, J.; Pham, A. T. P.; Poletti, D.; Puglisi, G.; Ross, C.; Segawa, Y.; Sherwin, B. D.; Silva-Feaver, M.; Siritanasak, P.; Stebor, N.; Suzuki, A.; Tajima, O.; Takakura, S.; Takatori, S.; Tanabe, D.; Tomaru, T.; Zahn, A.
United Kingdom, Chile, Japan, United States, Italy, France, Australia, Canada, Taiwan
Abstract
We report an improved measurement of the cosmic microwave background B-mode polarization power spectrum with the Polarbear experiment at 150 GHz. By adding new data collected during the second season of observations (2013-2014) to re-analyzed data from the first season (2012-2013), we have reduced twofold the band-power uncertainties. The band powers are reported over angular multipoles 500≤slant {\ell }≤slant 2100, where the dominant B-mode signal is expected to be due to the gravitational lensing of E-modes. We reject the null hypothesis of no B-mode polarization at a confidence of 3.1σ including both statistical and systematic uncertainties. We test the consistency of the measured B-modes with the Λ Cold Dark Matter (ΛCDM) framework by fitting for a single lensing amplitude parameter A L relative to the Planck 2015 best-fit model prediction. We obtain {A}L={0.60}-0.24+0.26({stat}{)}-0.04+0.00({inst}) ± 0.14(foreground) ± 0.04(multi), where {A}L=1 is the fiducial ΛCDM value.