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arXiv · 2008.12619

CMB-S4: Forecasting Constraints on Primordial Gravitational Waves

S4 Collaboration·Kevork Abazajian·Graeme E. Addison·Peter Adshead·Zeeshan Ahmed·Daniel Akerib·Aamir Ali·Steven W. Allen·David Alonso·Marcelo Alvarez·Mustafa A. Amin·Adam Anderson·Kam S. Arnold·Peter Ashton·Carlo Baccigalupi·Debbie Bard·Denis Barkats·Darcy Barron·Peter S. Barry·James G. Bartlett·Ritoban Basu Thakur·Nicholas Battaglia·Rachel Bean·Chris Bebek·Amy N. Bender·Bradford A. Benson·Federico Bianchini·Colin A. Bischoff·Lindsey Bleem·James J. Bock·Sebastian Bocquet·Kimberly K. Boddy·J. Richard Bond·Julian Borrill·François R. Bouchet·Thejs Brinckmann·Michael L. Brown·Sean Bryan·Victor Buza·Karen Byrum·Carlos Hervias Caimapo·Erminia Calabrese·Victoria Calafut·Robert Caldwell·John E. Carlstrom·Julien Carron·Thomas Cecil·Anthony Challinor·Clarence L. Chang·Yuji Chinone·Hsiao-Mei Sherry Cho·Asantha Cooray·Will Coulton·Thomas M. Crawford·Abigail Crites·Ari Cukierman·Francis-Yan Cyr-Racine·Tijmen de Haan·Jacques Delabrouille·Mark Devlin·Eleonora Di Valentino·Marion Dierickx·Matt Dobbs·Shannon Duff·Jo Dunkley·Cora Dvorkin·Joseph Eimer·Tucker Elleflot·Josquin Errard·Thomas Essinger-Hileman·Giulio Fabbian·Chang Feng·Simone Ferraro·Jeffrey P. Filippini·Raphael Flauger·Brenna Flaugher·Aurelien A. Fraisse·Andrei Frolov·Nicholas Galitzki·Patricio A. Gallardo·Silvia Galli·Ken Ganga·Martina Gerbino·Vera Gluscevic·Neil Goeckner-Wald·Daniel Green·Daniel Grin·Evan Grohs·Riccardo Gualtieri·Jon E. Gudmundsson·Ian Gullett·Nikhel Gupta·Salman Habib·Mark Halpern·Nils W. Halverson·Shaul Hanany·Kathleen Harrington·Masaya Hasegawa·Matthew Hasselfield·Masashi Hazumi
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Abstract

CMB-S4---the next-generation ground-based cosmic microwave background (CMB) experiment---is set to significantly advance the sensitivity of CMB measurements and enhance our understanding of the origin and evolution of the Universe, from the highest energies at the dawn of time through the growth of structure to the present day. Among the science cases pursued with CMB-S4, the quest for detecting primordial gravitational waves is a central driver of the experimental design. This work details the development of a forecasting framework that includes a power-spectrum-based semi-analytic projection tool, targeted explicitly towards optimizing constraints on the tensor-to-scalar ratio, $r$, in the presence of Galactic foregrounds and gravitational lensing of the CMB. This framework is unique in its direct use of information from the achieved performance of current Stage 2--3 CMB experiments to robustly forecast the science reach of upcoming CMB-polarization endeavors. The methodology allows for rapid iteration over experimental configurations and offers a flexible way to optimize the design of future experiments given a desired scientific goal. To form a closed-loop process, we couple this semi-analytic tool with map-based validation studies, which allow for the injection of additional complexity and verification of our forecasts with several independent analysis methods. We document multiple rounds of forecasts for CMB-S4 using this process and the resulting establishment of the current reference design of the primordial gravitational-wave component of the Stage-4 experiment, optimized to achieve our science goals of detecting primordial gravitational waves for $r > 0.003$ at greater than $5\sigma$, or, in the absence of a detection, of reaching an upper limit of $r < 0.001$ at $95\%$ CL.

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S4 Collaboration, Kevork Abazajian, Graeme E. Addison, Peter Adshead, Zeeshan Ahmed, Daniel Akerib, Aamir Ali, Steven W. Allen, David Alonso, Marcelo Alvarez, Mustafa A. Amin, Adam Anderson, Kam S. Arnold, Peter Ashton, Carlo Baccigalupi, Debbie Bard, Denis Barkats, Darcy Barron, Peter S. Barry, James G. Bartlett, Ritoban Basu Thakur, Nicholas Battaglia, Rachel Bean, Chris Bebek, Amy N. Bender, Bradford A. Benson, Federico Bianchini, Colin A. Bischoff, Lindsey Bleem, James J. Bock, Sebastian Bocquet, Kimberly K. Boddy, J. Richard Bond, Julian Borrill, François R. Bouchet, Thejs Brinckmann, Michael L. Brown, Sean Bryan, Victor Buza, Karen Byrum, Carlos Hervias Caimapo, Erminia Calabrese, Victoria Calafut, Robert Caldwell, John E. Carlstrom, Julien Carron, Thomas Cecil, Anthony Challinor, Clarence L. Chang, Yuji Chinone, Hsiao-Mei Sherry Cho, Asantha Cooray, Will Coulton, Thomas M. Crawford, Abigail Crites, Ari Cukierman, Francis-Yan Cyr-Racine, Tijmen de Haan, Jacques Delabrouille, Mark Devlin, Eleonora Di Valentino, Marion Dierickx, Matt Dobbs, Shannon Duff, Jo Dunkley, Cora Dvorkin, Joseph Eimer, Tucker Elleflot, Josquin Errard, Thomas Essinger-Hileman, Giulio Fabbian, Chang Feng, Simone Ferraro, Jeffrey P. Filippini, Raphael Flauger, Brenna Flaugher, Aurelien A. Fraisse, Andrei Frolov, Nicholas Galitzki, Patricio A. Gallardo, Silvia Galli, Ken Ganga, Martina Gerbino, Vera Gluscevic, Neil Goeckner-Wald, Daniel Green, Daniel Grin, Evan Grohs, Riccardo Gualtieri, Jon E. Gudmundsson, Ian Gullett, Nikhel Gupta, Salman Habib, Mark Halpern, Nils W. Halverson, Shaul Hanany, Kathleen Harrington, Masaya Hasegawa, Matthew Hasselfield, Masashi Hazumi. 2020-08-27. CMB-S4: Forecasting Constraints on Primordial Gravitational Waves. https://doi.org/10.3847/1538-4357/ac1596

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