Browsing by Autor "C. García-Quintero"

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Constraints on neutrino physics from DESI DR2 BAO and DR1 full shape
(American Physical Society, 2025) Willem Elbers; Alejandro Avilés; H. E. Noriega; D. Chebat; A. Menegas; Carlos S. Frenk; C. García-Quintero; D. Gonzalez; Mustapha Ishak; O. Lahav
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><</a:mo> <a:mi>z</a:mi> <a:mo><</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><</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><</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><</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><</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><</ib:mo> <ib:mn>0.193</ib:mn> <ib:mtext> </ib:mtext> <ib:mtext> </ib:mtext> <ib:mi>eV</ib:mi> </ib:math> (95%).
Extended dark energy analysis using DESI DR2 BAO measurements
(American Physical Society, 2025) K. Lodha; R. Calderón; William L. Matthewson; Arman Shafieloo; M Ishak; Jian Pan; C. García-Quintero; D Huterer; Georgios Valogiannis; Luís Alfonso Ureña López
We conduct an extended analysis of dark energy constraints, in support of the findings of the Dark Energy Spectroscopic Instrument (DESI) second data release cosmology key paper, including DESI data, Planck cosmic microwave background observations, and three different supernova compilations. Using a broad range of parametric and nonparametric methods, we explore the dark energy phenomenology and find consistent trends across all approaches, in good agreement with the <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:msub><a:mi>w</a:mi><a:mn>0</a:mn></a:msub><a:msub><a:mi>w</a:mi><a:mi>a</a:mi></a:msub><a:mi>CDM</a:mi></a:math> (cold dark matter) key paper results. Even with the additional flexibility introduced by nonparametric approaches, such as binning and Gaussian processes, we find that extending <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mi mathvariant="normal">Λ</c:mi><c:mi>CDM</c:mi></c:math> to include a two-parameter <f:math xmlns:f="http://www.w3.org/1998/Math/MathML" display="inline"><f:mi>w</f:mi><f:mo stretchy="false">(</f:mo><f:mi>z</f:mi><f:mo stretchy="false">)</f:mo></f:math> is sufficient to capture the trends present in the data. Finally, we examine three dark energy classes with distinct dynamics, including quintessence scenarios satisfying <j:math xmlns:j="http://www.w3.org/1998/Math/MathML" display="inline"><j:mi>w</j:mi><j:mo>≥</j:mo><j:mo>−</j:mo><j:mn>1</j:mn></j:math>, to explore what underlying physics can explain such deviations. The current data indicate a clear preference for models that feature a phantom crossing; although alternatives lacking this feature are disfavored, they cannot yet be ruled out. Our analysis confirms that the evidence for dynamical dark energy, particularly at low redshift (<l:math xmlns:l="http://www.w3.org/1998/Math/MathML" display="inline"><l:mi>z</l:mi><l:mo>≲</l:mo><l:mn>0.3</l:mn></l:math>), is robust and stable under different modeling choices.