Constraints on neutrino physics from DESI DR2 BAO and DR1 full shape

The Dark Energy Spectroscopic Instrument (DESI) Collaboration has obtained robust measurements of baryon acoustic oscillations in the redshift range <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mn>0.1</a:mn> <a:mo>&lt;</a:mo> <a:mi>z</a:mi> <a:mo>&lt;</a:mo> <a:mn>4.2</a:mn> </a:math> , based on the Lyman- <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:mi>α</c:mi> </c:math> forest and galaxies from data release 2. We combine these measurements with cosmic microwave background (CMB) data from and the Atacama Cosmology Telescope to place our tightest constraints yet on the sum of neutrino masses. Assuming the cosmological <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:mi mathvariant="normal">Λ</e:mi> <e:mi>CDM</e:mi> </e:math> model and three degenerate neutrino states, we find <h:math xmlns:h="http://www.w3.org/1998/Math/MathML" display="inline"> <h:mo>∑</h:mo> <h:msub> <h:mi>m</h:mi> <h:mi>ν</h:mi> </h:msub> <h:mo>&lt;</h:mo> <h:mn>0.0642</h:mn> <h:mtext> </h:mtext> <h:mtext> </h:mtext> <h:mi>eV</h:mi> </h:math> (95%) with a marginalized error of <j:math xmlns:j="http://www.w3.org/1998/Math/MathML" display="inline"> <j:mi>σ</j:mi> <j:mo stretchy="false">(</j:mo> <j:mo>∑</j:mo> <j:msub> <j:mi>m</j:mi> <j:mi>ν</j:mi> </j:msub> <j:mo stretchy="false">)</j:mo> <j:mo>=</j:mo> <j:mn>0.020</j:mn> <j:mtext> </j:mtext> <j:mtext> </j:mtext> <j:mi>eV</j:mi> </j:math> . We also constrain the effective number of neutrino species, finding <n:math xmlns:n="http://www.w3.org/1998/Math/MathML" display="inline"> <n:msub> <n:mi>N</n:mi> <n:mi>eff</n:mi> </n:msub> <n:mo>=</n:mo> <n:mn>3.2</n:mn> <n:msubsup> <n:mn>3</n:mn> <n:mrow> <n:mo>−</n:mo> <n:mn>0.34</n:mn> </n:mrow> <n:mrow> <n:mo>+</n:mo> <n:mn>0.35</n:mn> </n:mrow> </n:msubsup> </n:math> (95%), in line with the Standard Model prediction. When accounting for neutrino oscillation constraints, we find a preference for the normal mass ordering and an upper limit on the lightest neutrino mass of <p:math xmlns:p="http://www.w3.org/1998/Math/MathML" display="inline"> <p:msub> <p:mi>m</p:mi> <p:mi>l</p:mi> </p:msub> <p:mo>&lt;</p:mo> <p:mn>0.023</p:mn> <p:mtext> </p:mtext> <p:mtext> </p:mtext> <p:mi>eV</p:mi> </p:math> (95%). However, we determine using frequentist and Bayesian methods that our constraints are in tension with the lower limits derived from neutrino oscillations. Correcting for the physical boundary at zero mass, we report a 95% Feldman-Cousins upper limit of <r:math xmlns:r="http://www.w3.org/1998/Math/MathML" display="inline"> <r:mo>∑</r:mo> <r:msub> <r:mi>m</r:mi> <r:mi>ν</r:mi> </r:msub> <r:mo>&lt;</r:mo> <r:mn>0.053</r:mn> <r:mtext> </r:mtext> <r:mtext> </r:mtext> <r:mi>eV</r:mi> </r:math> , breaching the lower limit from neutrino oscillations. Considering a more general Bayesian analysis with an effective cosmological neutrino mass parameter, <t:math xmlns:t="http://www.w3.org/1998/Math/MathML" display="inline"> <t:mo>∑</t:mo> <t:msub> <t:mi>m</t:mi> <t:mrow> <t:mi>ν</t:mi> <t:mo>,</t:mo> <t:mi>eff</t:mi> </t:mrow> </t:msub> </t:math> , that allows for negative energy densities and removes unsatisfactory prior weight effects, we derive constraints that are in <v:math xmlns:v="http://www.w3.org/1998/Math/MathML" display="inline"> <v:mn>3</v:mn> <v:mi>σ</v:mi> </v:math> tension with the same oscillation limit, while the error rises to <x:math xmlns:x="http://www.w3.org/1998/Math/MathML" display="inline"> <x:mi>σ</x:mi> <x:mo stretchy="false">(</x:mo> <x:mo>∑</x:mo> <x:msub> <x:mi>m</x:mi> <x:mrow> <x:mi>ν</x:mi> <x:mo>,</x:mo> <x:mi>eff</x:mi> </x:mrow> </x:msub> <x:mo stretchy="false">)</x:mo> <x:mo>=</x:mo> <x:mn>0.053</x:mn> <x:mtext> </x:mtext> <x:mtext> </x:mtext> <x:mi>eV</x:mi> </x:math> . In the absence of unknown systematics, this finding could be interpreted as a hint of new physics not necessarily related to neutrinos. The preference of DESI and CMB data for an evolving dark energy model offers one possible solution. In the <bb:math xmlns:bb="http://www.w3.org/1998/Math/MathML" display="inline"> <bb:msub> <bb:mi>w</bb:mi> <bb:mn>0</bb:mn> </bb:msub> <bb:msub> <bb:mi>w</bb:mi> <bb:mi>a</bb:mi> </bb:msub> <bb:mi>CDM</bb:mi> </bb:math> model, we find <db:math xmlns:db="http://www.w3.org/1998/Math/MathML" display="inline"> <db:mo>∑</db:mo> <db:msub> <db:mi>m</db:mi> <db:mi>ν</db:mi> </db:msub> <db:mo>&lt;</db:mo> <db:mn>0.163</db:mn> <db:mtext> </db:mtext> <db:mtext> </db:mtext> <db:mi>eV</db:mi> </db:math> (95%), relaxing the neutrino tension. These constraints all rely on the effects of neutrinos on the cosmic expansion history. Using full-shape power spectrum measurements of data release 1 galaxies, we place complementary constraints that rely on neutrino free streaming. Our strongest such limit in <fb:math xmlns:fb="http://www.w3.org/1998/Math/MathML" display="inline"> <fb:mi mathvariant="normal">Λ</fb:mi> <fb:mi>CDM</fb:mi> </fb:math> , using selected CMB priors, is <ib:math xmlns:ib="http://www.w3.org/1998/Math/MathML" display="inline"> <ib:mo>∑</ib:mo> <ib:msub> <ib:mi>m</ib:mi> <ib:mi>ν</ib:mi> </ib:msub> <ib:mo>&lt;</ib:mo> <ib:mn>0.193</ib:mn> <ib:mtext> </ib:mtext> <ib:mtext> </ib:mtext> <ib:mi>eV</ib:mi> </ib:math> (95%).

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Physical review. D/Physical review. D.
Published
2025-08-04
DOI
https://doi.org/10.1103/w9pk-xsk7
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37
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Astrophysics and Cosmic Phenomena
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article
Field-Weighted Citation Impact
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article

Constraints on neutrino physics from DESI DR2 BAO and DR1 full shape

D. Kirkby, A. Menegas, C. Ravoux, H. E. Noriega et al.
37 citations
Physical review. D/Physical review. D.
Astrophysics and Cosmic Phenomena
69.20
article

Constraints on neutrino physics from DESI DR2 BAO and DR1 full shape

D. Kirkby, A. Menegas, C. Ravoux, H. E. Noriega, Will J. Percival, C. García-Quintero, Molly Wolfson, Rongpu Zhou, Abbé M Whitford, Willem Elbers, Michael Walther, E. Chaussidon, C. Poppett, Michael S. Schubnell, W. Turner, N. Deiosso, Matthew M. Pieri, D. J. Eisenstein, Graziano Rossi, Alejandro Avilés, N. Palanque‐Delabrouille, S. Nadathur, H. K. Herrera-Alcantar, J. Rohlf, E. Armengaud, Jeffrey A. Newman, J. Ereza, Gregory Tarlé, Kyle Dawson, Andreu Font-Ribera, Carlos S. Frenk, L. Le Guillou, Licia Verde, Gustavo Niz, D. Bianchi, David J. Schlegel, Ignasi Pérez-Ràfols, Axel de la Macorra, Héctor Gil-Marín, Martin Landriau, O. Alves, Simone Ferraro, Lado Samushia, D Huterer, A. Brodzeller, Francesco Sinigaglia, M. E. Levi, S. Brieden, William L. Matthewson, Gaston Gutierrez, O. Lahav, Anthony Kremin, Eusebio Sanchez, Satya Gontcho A Gontcho, J. Mena-Fernández, S. BenZvi, Alexie Leauthaud, A. Carnero Rosell, Cheng Zhao, ENRIQUE GAZTAÑAGA, Andrei Cuceu, Cullan Howlett, J. Chaves-Montero, Arjun T. Dey, E. Paillas, Peter L. Taylor, J. E. Forero-Romero, Steven P. Ahlen, Andrew P. Cooper, Krishna Naidoo, Aaron Meisner, Pauline Zarrouk, Theodore S. Kisner, Biprateep Dey, M. Rashkovetskyi, C. Ramírez-Pérez, John Moustakas, Ashley J. Ross, Lidia Casas, U. Andrade, Arnaud de Mattia, Mustapha Ishak, Qiong Li, Hee‐Jong Seo, M. Vargas-Magaña, T. Tan, R. Calderón, C. Lamman, V. Ruhlmann-Kleider, F. J. Castander, C. Yèche, F. Prada, K. Lodha, Hu Zou, S. Cole, B. A. Weaver, R. Miquel, R. Kehoe, Mike Charles, L. H. Garrison, Z. Ding, A. X. Gonzalez-Morales, Peter Doel, Marc Manera, D. Gonzalez, T. Claybaugh, C. Magneville, E. Burtin, Donal Brooks, S. He, R. E. A. Canning, S. Juneau, J. Behera, D. Rabinowitz, D. Sprayberry, D. Chebat, M. Herbold, M. Abdul-Karim, H. Rivera-Morales
article en
37 citations

Abstract

The Dark Energy Spectroscopic Instrument (DESI) Collaboration has obtained robust measurements of baryon acoustic oscillations in the redshift range <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mn>0.1</a:mn> <a:mo>&lt;</a:mo> <a:mi>z</a:mi> <a:mo>&lt;</a:mo> <a:mn>4.2</a:mn> </a:math> , based on the Lyman- <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:mi>α</c:mi> </c:math> forest and galaxies from data release 2. We combine these measurements with cosmic microwave background (CMB) data from and the Atacama Cosmology Telescope to place our tightest constraints yet on the sum of neutrino masses. Assuming the cosmological <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:mi mathvariant="normal">Λ</e:mi> <e:mi>CDM</e:mi> </e:math> model and three degenerate neutrino states, we find <h:math xmlns:h="http://www.w3.org/1998/Math/MathML" display="inline"> <h:mo>∑</h:mo> <h:msub> <h:mi>m</h:mi> <h:mi>ν</h:mi> </h:msub> <h:mo>&lt;</h:mo> <h:mn>0.0642</h:mn> <h:mtext> </h:mtext> <h:mtext> </h:mtext> <h:mi>eV</h:mi> </h:math> (95%) with a marginalized error of <j:math xmlns:j="http://www.w3.org/1998/Math/MathML" display="inline"> <j:mi>σ</j:mi> <j:mo stretchy="false">(</j:mo> <j:mo>∑</j:mo> <j:msub> <j:mi>m</j:mi> <j:mi>ν</j:mi> </j:msub> <j:mo stretchy="false">)</j:mo> <j:mo>=</j:mo> <j:mn>0.020</j:mn> <j:mtext> </j:mtext> <j:mtext> </j:mtext> <j:mi>eV</j:mi> </j:math> . We also constrain the effective number of neutrino species, finding <n:math xmlns:n="http://www.w3.org/1998/Math/MathML" display="inline"> <n:msub> <n:mi>N</n:mi> <n:mi>eff</n:mi> </n:msub> <n:mo>=</n:mo> <n:mn>3.2</n:mn> <n:msubsup> <n:mn>3</n:mn> <n:mrow> <n:mo>−</n:mo> <n:mn>0.34</n:mn> </n:mrow> <n:mrow> <n:mo>+</n:mo> <n:mn>0.35</n:mn> </n:mrow> </n:msubsup> </n:math> (95%), in line with the Standard Model prediction. When accounting for neutrino oscillation constraints, we find a preference for the normal mass ordering and an upper limit on the lightest neutrino mass of <p:math xmlns:p="http://www.w3.org/1998/Math/MathML" display="inline"> <p:msub> <p:mi>m</p:mi> <p:mi>l</p:mi> </p:msub> <p:mo>&lt;</p:mo> <p:mn>0.023</p:mn> <p:mtext> </p:mtext> <p:mtext> </p:mtext> <p:mi>eV</p:mi> </p:math> (95%). However, we determine using frequentist and Bayesian methods that our constraints are in tension with the lower limits derived from neutrino oscillations. Correcting for the physical boundary at zero mass, we report a 95% Feldman-Cousins upper limit of <r:math xmlns:r="http://www.w3.org/1998/Math/MathML" display="inline"> <r:mo>∑</r:mo> <r:msub> <r:mi>m</r:mi> <r:mi>ν</r:mi> </r:msub> <r:mo>&lt;</r:mo> <r:mn>0.053</r:mn> <r:mtext> </r:mtext> <r:mtext> </r:mtext> <r:mi>eV</r:mi> </r:math> , breaching the lower limit from neutrino oscillations. Considering a more general Bayesian analysis with an effective cosmological neutrino mass parameter, <t:math xmlns:t="http://www.w3.org/1998/Math/MathML" display="inline"> <t:mo>∑</t:mo> <t:msub> <t:mi>m</t:mi> <t:mrow> <t:mi>ν</t:mi> <t:mo>,</t:mo> <t:mi>eff</t:mi> </t:mrow> </t:msub> </t:math> , that allows for negative energy densities and removes unsatisfactory prior weight effects, we derive constraints that are in <v:math xmlns:v="http://www.w3.org/1998/Math/MathML" display="inline"> <v:mn>3</v:mn> <v:mi>σ</v:mi> </v:math> tension with the same oscillation limit, while the error rises to <x:math xmlns:x="http://www.w3.org/1998/Math/MathML" display="inline"> <x:mi>σ</x:mi> <x:mo stretchy="false">(</x:mo> <x:mo>∑</x:mo> <x:msub> <x:mi>m</x:mi> <x:mrow> <x:mi>ν</x:mi> <x:mo>,</x:mo> <x:mi>eff</x:mi> </x:mrow> </x:msub> <x:mo stretchy="false">)</x:mo> <x:mo>=</x:mo> <x:mn>0.053</x:mn> <x:mtext> </x:mtext> <x:mtext> </x:mtext> <x:mi>eV</x:mi> </x:math> . In the absence of unknown systematics, this finding could be interpreted as a hint of new physics not necessarily related to neutrinos. The preference of DESI and CMB data for an evolving dark energy model offers one possible solution. In the <bb:math xmlns:bb="http://www.w3.org/1998/Math/MathML" display="inline"> <bb:msub> <bb:mi>w</bb:mi> <bb:mn>0</bb:mn> </bb:msub> <bb:msub> <bb:mi>w</bb:mi> <bb:mi>a</bb:mi> </bb:msub> <bb:mi>CDM</bb:mi> </bb:math> model, we find <db:math xmlns:db="http://www.w3.org/1998/Math/MathML" display="inline"> <db:mo>∑</db:mo> <db:msub> <db:mi>m</db:mi> <db:mi>ν</db:mi> </db:msub> <db:mo>&lt;</db:mo> <db:mn>0.163</db:mn> <db:mtext> </db:mtext> <db:mtext> </db:mtext> <db:mi>eV</db:mi> </db:math> (95%), relaxing the neutrino tension. These constraints all rely on the effects of neutrinos on the cosmic expansion history. Using full-shape power spectrum measurements of data release 1 galaxies, we place complementary constraints that rely on neutrino free streaming. Our strongest such limit in <fb:math xmlns:fb="http://www.w3.org/1998/Math/MathML" display="inline"> <fb:mi mathvariant="normal">Λ</fb:mi> <fb:mi>CDM</fb:mi> </fb:math> , using selected CMB priors, is <ib:math xmlns:ib="http://www.w3.org/1998/Math/MathML" display="inline"> <ib:mo>∑</ib:mo> <ib:msub> <ib:mi>m</ib:mi> <ib:mi>ν</ib:mi> </ib:msub> <ib:mo>&lt;</ib:mo> <ib:mn>0.193</ib:mn> <ib:mtext> </ib:mtext> <ib:mtext> </ib:mtext> <ib:mi>eV</ib:mi> </ib:math> (95%).

Physical review. D/Physical review. D.Vol. 112(8)
Boston University (US), University of Science and Technology (YE), Institució Catalana de Recerca i Estudis Avançats (ES), Universidad Complutense de Madrid (ES), Universitat Autònoma de Barcelona (ES), Universidad de Guanajuato (MX), Fermi National Accelerator Laboratory (US), Institute of Space Sciences (ES), University of Arizona (US), Lawrence Berkeley National Laboratory (US), University of Waterloo (CA), Universidad de La Laguna (ES), The University of Texas at Dallas (US), The University of Queensland (AU), University of Pittsburgh (US), Southern Methodist University (US), Ilia State University (GE), Perimeter Institute (CA), University of California, Santa Cruz (US), University of Toronto (CA), University of Milan (IT), Kansas State University (US), Durham University (GB), Chinese Academy of Sciences (CN), Université Clermont Auvergne (FR), Czech Academy of Sciences (CZ), University of California, Irvine (US), Aix-Marseille Université (FR), University of Utah (US), National Tsing Hua University (TW), Université Paris-Saclay (FR), University of Michigan (US), Korea Astronomy and Space Science Institute (KR), Institut d'Astrophysique de Paris (FR), Brera Astronomical Observatory (IT), Evgeni Kharadze Georgian National Astrophysical Observatory (GE), University of California System (US), Sejong University (KR), Coast Mountain College (CA), Yale University (US), Institut d'Estudis Espacials de Catalunya (ES), Excellence Cluster Origins (DE), Laboratoire de Physique Nucléaire et de Hautes Énergies (FR), Royal Observatory (GB), Ohio University (US), Instituto de Estudios Avanzados (VE), FZU ‒ Institute of Physics of the Academy of Sciences of the Czech Republic (CZ), Center for Astrophysics Harvard & Smithsonian (US), Instituto de Astrofísica de Canarias (ES), Barcelona Institute of Science and Technology (ES), Community Science and Data Center (US), Laboratoire de Physique Subatomique et de Cosmologie (FR), NSF NOIRLab (US), Institute of Space Science - INFLPR Subsidiary (RO), Universidad de Los Andes (BO), Flatiron Health (United States) (US), Instituto de Astrofísica de Andalucía (ES), National Astronomical Observatories (CN), University of Chinese Academy of Sciences (CN), Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (ES), Flatiron Institute (US), Institute of Science and Technology, University College London (GB), The Ohio State University (US), University of Rochester (US), University of Portsmouth (GB), Universitat de Barcelona (ES), Korea University of Science and Technology (KR), Universidad Nacional Autónoma de México (MX), Universidad Diego Portales (CL), Siena College (US), University of California, Berkeley (US), Universitat Politècnica de Catalunya (ES), University of Edinburgh (GB), Tsinghua University (CN)
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