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arXiv · 1903.04763

Messengers from the Early Universe: Cosmic Neutrinos and Other Light Relics

Daniel Green·Mustafa A. Amin·Joel Meyers·Benjamin Wallisch·Kevork N. Abazajian·Muntazir Abidi·Peter Adshead·Zeeshan Ahmed·Behzad Ansarinejad·Robert Armstrong·Carlo Baccigalupi·Kevin Bandura·Darcy Barron·Nicholas Battaglia·Daniel Baumann·Keith Bechtol·Charles Bennett·Bradford Benson·Florian Beutler·Colin Bischoff·Lindsey Bleem·J. Richard Bond·Julian Borrill·Elizabeth Buckley-Geer·Cliff Burgess·John E. Carlstrom·Emanuele Castorina·Anthony Challinor·Xingang Chen·Asantha Cooray·William Coulton·Nathaniel Craig·Thomas Crawford·Francis-Yan Cyr-Racine·Guido D'Amico·Marcel Demarteau·Olivier Doré·Duan Yutong·Joanna Dunkley·Cora Dvorkin·John Ellison·Alexander van Engelen·Stephanie Escoffier·Tom Essinger-Hileman·Giulio Fabbian·Jeffrey Filippini·Raphael Flauger·Simon Foreman·George Fuller·Marcos A. G. Garcia·Juan García-Bellido·Martina Gerbino·Vera Gluscevic·Satya Gontcho A Gontcho·Krzysztof M. Górski·Daniel Grin·Evan Grohs·Jon E. Gudmundsson·Shaul Hanany·Will Handley·J. Colin Hill·Christopher M. Hirata·Renée Hložek·Gilbert Holder·Shunsaku Horiuchi·Dragan Huterer·Kenji Kadota·Marc Kamionkowski·Ryan E. Keeley·Rishi Khatri·Theodore Kisner·Jean-Paul Kneib·Lloyd Knox·Savvas M. Koushiappas·Ely D. Kovetz·Benjamin L'Huillier·Ofer Lahav·Massimiliano Lattanzi·Hayden Lee·Michele Liguori·Tongyan Lin·Marilena Loverde·Mathew Madhavacheril·Kiyoshi Masui·Jeff McMahon·Matthew McQuinn·P. Daniel Meerburg·Mehrdad Mirbabayi·Pavel Motloch·Suvodip Mukherjee·Julian B. Munõz·Johanna Nagy·Laura Newburgh·Michael D. Niemack·Andrei Nomerotski·Lyman Page·Francesco Piacentni·Elena Pierpaoli·Levon Pogosian·Clement Pryke

Abstract

The hot dense environment of the early universe is known to have produced large numbers of baryons, photons, and neutrinos. These extreme conditions may have also produced other long-lived species, including new light particles (such as axions or sterile neutrinos) or gravitational waves. The gravitational effects of any such light relics can be observed through their unique imprint in the cosmic microwave background (CMB), the large-scale structure, and the primordial light element abundances, and are important in determining the initial conditions of the universe. We argue that future cosmological observations, in particular improved maps of the CMB on small angular scales, can be orders of magnitude more sensitive for probing the thermal history of the early universe than current experiments. These observations offer a unique and broad discovery space for new physics in the dark sector and beyond, even when its effects would not be visible in terrestrial experiments or in astrophysical environments. A detection of an excess light relic abundance would be a clear indication of new physics and would provide the first direct information about the universe between the times of reheating and neutrino decoupling one second later.

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Daniel Green, Mustafa A. Amin, Joel Meyers, Benjamin Wallisch, Kevork N. Abazajian, Muntazir Abidi, Peter Adshead, Zeeshan Ahmed, Behzad Ansarinejad, Robert Armstrong, Carlo Baccigalupi, Kevin Bandura, Darcy Barron, Nicholas Battaglia, Daniel Baumann, Keith Bechtol, Charles Bennett, Bradford Benson, Florian Beutler, Colin Bischoff, Lindsey Bleem, J. Richard Bond, Julian Borrill, Elizabeth Buckley-Geer, Cliff Burgess, John E. Carlstrom, Emanuele Castorina, Anthony Challinor, Xingang Chen, Asantha Cooray, William Coulton, Nathaniel Craig, Thomas Crawford, Francis-Yan Cyr-Racine, Guido D'Amico, Marcel Demarteau, Olivier Doré, Duan Yutong, Joanna Dunkley, Cora Dvorkin, John Ellison, Alexander van Engelen, Stephanie Escoffier, Tom Essinger-Hileman, Giulio Fabbian, Jeffrey Filippini, Raphael Flauger, Simon Foreman, George Fuller, Marcos A. G. Garcia, Juan García-Bellido, Martina Gerbino, Vera Gluscevic, Satya Gontcho A Gontcho, Krzysztof M. Górski, Daniel Grin, Evan Grohs, Jon E. Gudmundsson, Shaul Hanany, Will Handley, J. Colin Hill, Christopher M. Hirata, Renée Hložek, Gilbert Holder, Shunsaku Horiuchi, Dragan Huterer, Kenji Kadota, Marc Kamionkowski, Ryan E. Keeley, Rishi Khatri, Theodore Kisner, Jean-Paul Kneib, Lloyd Knox, Savvas M. Koushiappas, Ely D. Kovetz, Benjamin L'Huillier, Ofer Lahav, Massimiliano Lattanzi, Hayden Lee, Michele Liguori, Tongyan Lin, Marilena Loverde, Mathew Madhavacheril, Kiyoshi Masui, Jeff McMahon, Matthew McQuinn, P. Daniel Meerburg, Mehrdad Mirbabayi, Pavel Motloch, Suvodip Mukherjee, Julian B. Munõz, Johanna Nagy, Laura Newburgh, Michael D. Niemack, Andrei Nomerotski, Lyman Page, Francesco Piacentni, Elena Pierpaoli, Levon Pogosian, Clement Pryke. 2019-03-12. Messengers from the Early Universe: Cosmic Neutrinos and Other Light Relics. https://arxiv.org/abs/1903.04763

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