Hans P. Paar

Measurement of the Cosmic Microwave Background Polarization Lensing Power Spectrum with the POLARBEAR experiment

Gravitational lensing due to the large-scale distribution of matter in the cosmos distorts the primordial cosmic microwave background (CMB) and thereby induces new, small-scale B-mode polarization. This signal carries detailed information about the distribution of all the gravitating matter between the observer and CMB last scattering surface. We report the first direct evidence for polarization lensing based on purely CMB information, from using the four-point correlations of even- and odd-parity E- and B-mode polarization mapped over ∼30 square degrees of the sky measured by the POLARBEAR experiment. These data were analyzed using a blind analysis framework and checked for spurious systematic contamination using null tests and simulations. Evidence for the signal of polarization lensing and lensing B modes is found at 4.2σ (stat+sys) significance. The amplitude of matter fluctuations is measured with a precision of 27%, and is found to be consistent with the Lambda cold dark matter cosmological model. This measurement demonstrates a new technique, capable of mapping all gravitating matter in the Universe, sensitive to the sum of neutrino masses, and essential for cleaning the lensing B-mode signal in searches for primordial gravitational waves.

POLARBEAR constraints on cosmic birefringence and primordial magnetic fields

Author(s): Ade, PAR; Arnold, K; Atlas, M; Baccigalupi, C; Barron, D; Boettger, D; Borrill, J; Chapman, S; Chinone, Y; Cukierman, A; Dobbs, M; Ducout, A; Dunner, R; Elleflot, T; Errard, J; Fabbian, G; Feeney, S; Feng, C; Gilbert, A; Goeckner-Wald, N; Groh, J; Hall, G; Halverson, NW; Hasegawa, M; Hattori, K; Hazumi, M; Hill, C; Holzapfel, WL; Hori, Y; Howe, L; Inoue, Y; Jaehnig, GC; Jaffe, AH; Jeong, O; Katayama, N; Kaufman, JP; Keating, B; Kermish, Z; Keskitalo, R; Kisner, T; Kusaka, A; Le Jeune, M; Lee, AT; Leitch, EM; Leon, D; Li, Y; Linder, E; Lowry, L; Matsuda, F; Matsumura, T; Miller, N; Montgomery, J; Myers, MJ; Navaroli, M; Nishino, H; Okamura, T; Paar, H; Peloton, J; Pogosian, L; Poletti, D; Puglisi, G; Raum, C; Rebeiz, G; Reichardt, CL; Richards, PL; Ross, C; Rotermund, KM; Schenck, DE; Sherwin, BD; Shimon, M; Shirley, I; Siritanasak, P; Smecher, G; Stebor, N; Steinbach, B; Suzuki, A; Suzuki, JI; Tajima, O; Takakura, S; Tikhomirov, A; Tomaru, T; Whitehorn, N; Wilson, B; Yadav, A; Zahn, A | Abstract:

The bolometric focal plane array of the POLARBEAR CMB experiment

The POLARBEAR Cosmic Microwave Background (CMB) polarization experiment is currently observing from the Atacama Desert in Northern Chile. It will characterize the expected B-mode polarization due to gravitational lensing of the CMB, and search for the possible B-mode signature of inflationary gravitational waves. Its 250 mK focal plane detector array consists of 1,274 polarization-sensitive antenna-coupled bolometers, each with an associated lithographed band-defining filter. Each detector’s planar antenna structure is coupled to the telescope’s optical system through a contacting dielectric lenslet, an architecture unique in current CMB experiments. We present the initial characterization of this focal plane.

Contributions of Cherenkov light to the signals from lead tungstate crystals

Results are presented of detailed measurements of the signals generated by high-energy electrons and muons in lead tungstate crystals. A significant fraction of the light produced in these crystals and detected by photomultiplier tubes is the result of the Cherenkov mechanism. This is concluded from the angular dependence of the signals and from their time structure. Depending on the orientation of the crystals and on the particle type, Cherenkov light may account for up to 15% of the total signals. r 2007 Elsevier B.V. All rights reserved. PACS: 29.40.Ka; 29.40.Mc; 29.40.Vj

The Simons Array: expanding POLARBEAR to three multi-chroic telescopes

The Simons Array is an expansion of the POLARBEAR cosmic microwave background (CMB) polarization experiment currently observing from the Atacama Desert in Northern Chile. This expansion will create an array of three 3.5m telescopes each coupled to a multichroic bolometric receiver. The Simons Array will have the sensitivity to produce a ≥ 5σ detection of inationary gravitational waves with a tensor-to-scalar ratio r ≥ 0:01, detect the known minimum 58 meV sum of the neutrino masses with 3σ confidence when combined with a next-generation baryon acoustic oscillation measurement, and make a lensing map of large-scale structure over the 80% of the sky available from its Chilean site. These goals require high sensitivity and the ability to extract the CMB signal from contaminating astrophysical foregrounds; these requirements are met by coupling the three high-throughput telescopes to novel multichroic lenslet-coupled pixels each measuring CMB photons in both linear polarization states over multiple spectral bands. We present the status of this instrument already under construction, and an analysis of its capabilities.

POLARBEAR: Ultra-high energy physics with measurements of CMB polarization

POLARBEAR is a ground‐based experiment to measure polarization anisotropy in the Cosmic Microwave Background. It is designed to have a combination of sensitivity, foreground mitigation, and rejection of systematic errors to search for the B‐mode signature of Inflationary gravity waves over much of the parameter range suggested by simple power‐law Inflation models. POLARBEAR is designed to detect a gravitational‐wave signature with a tensor‐to‐scalar ratio r as low as 0.025 (95% confidence). POLARBEAR will also measure polarized lensing of the Cosmic Microwave Background which will give valuable information on large‐scale structure at z>1 and bound the total mass of the neutrinos. POLARBEAR will have a 3.5 meter primary meter giving it an angular resolution of 3.0′ at its main observation frequency band centered at 150 GHz. The 250 mK focal plane design contains 637 dual‐polarization pixels (1274 bolometers) that are coupled to the telescope using microlithographed planar antennas. The experiment will be sited in the Atacama Desert in Chile at 5000 meter (16,500 ft) altitude starting in 2009 after a prototype testing stage at Cedar Flats California. The first configuration of the experiment will observe at only one frequency band with the first season at 150 GHz and the second at 220 GHz. The optics will be upgraded to have simultaneous observations in those two bands in the third season of observations. POLARBEAR and QUIET will observe the same sky patches, and together they will have frequency bands at 30, 40, 90, 150, and 220 GHz giving broad coverage of galactic foregrounds and a valuable cross‐check by comparison of polarization maps. In POLARBEAR, polarization systematic errors are mitigated by a continuously rotating 50 K half‐wave plate and an observation strategy that takes advantage of parallactic angle rotation to rotate the experiment relative to polarization patterns on the sky.

A Measurement of the Cosmic Microwave Background B-mode Polarization Power Spectrum at Subdegree Scales from Two Years of polarbear Data

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

POLARBEAR-2: An instrument for CMB polarization measurements

500\leqslant {\ell }\leqslant 2100

Measuring gravitational lensing of the cosmic microwave background using cross correlation with large scale structure

, 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

Measurement of the contribution of neutrons to hadron calorimeter signals

{A}_{L}={0.60}_{-0.24}^{+0.26}(\mathrm{stat}{)}_{-0.04}^{+0.00}(\mathrm{inst})