002861697 001__ 2861697
002861697 005__ 20240913045504.0
002861697 0248_ $$aoai:cds.cern.ch:2861697$$pcerncds:FULLTEXT$$pcerncds:CERN:FULLTEXT$$pcerncds:CERN
002861697 0247_ $$2DOI$$9APS$$a10.1103/PhysRevD.108.L121301$$qpublication
002861697 037__ $$9arXiv$$aarXiv:2306.05460$$chep-ph
002861697 037__ $$9arXiv:reportnumber$$aCERN-TH-2023-103
002861697 035__ $$9arXiv$$aoai:arXiv.org:2306.05460
002861697 035__ $$9Inspire$$aoai:inspirehep.net:2667553$$d2024-09-12T11:54:42Z$$h2024-09-13T02:00:10Z$$mmarcxml$$ttrue$$uhttps://inspirehep.net/api/oai2d
002861697 035__ $$9Inspire$$a2667553
002861697 041__ $$aeng
002861697 100__ $$aCielo, Mattia$$jORCID:0000-0002-5036-3550$$uINFN, Naples$$uNaples U.$$vDipartimento di Fisica E. Pancini, Naples, and INFN, Sezione di Napoli, Monte S. Angelo I-80126 Naples, Italy
002861697 245__ $$9APS$$a<math display="inline"><msub><mi>N</mi><mrow><mi>eff</mi></mrow></msub></math> in the Standard Model at NLO is 3.043
002861697 246__ $$9arXiv$$aNeff in the Standard Model at NLO is 3.043
002861697 269__ $$c2023-06-08
002861697 260__ $$c2023-12-13
002861697 300__ $$a6 p
002861697 500__ $$9arXiv$$a4 pages, 2 figures. v2: Added a paragraph discussing electroweak
corrections and other processes at O(alpha). v3: matches published version.
References added, typos fixed
002861697 520__ $$9APS$$aThe effective number of relativistic neutrino species is a fundamental probe of the early Universe, and its measurement represents a key constraint on many scenarios beyond the Standard Model of Particle Physics. In light of this, an accurate prediction of <math display="inline"><msub><mi>N</mi><mi>eff</mi></msub></math> in the Standard Model is of pivotal importance. In this work, we consider the last ingredient needed to accurately calculate <math display="inline"><msubsup><mi>N</mi><mi>eff</mi><mrow><mi>SM</mi></mrow></msubsup></math>: standard zero and finite-temperature QED corrections to <math display="inline"><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>-</mo></msup><mo stretchy="false">↔</mo><mi>ν</mi><mover accent="true"><mi>ν</mi><mo stretchy="false">¯</mo></mover></math> interaction rates during neutrino decoupling at temperatures around <math display="inline"><mi>T</mi><mo>∼</mo><mi>MeV</mi></math>. We find that this effect leads to a reduction of <math display="inline"><mo>-</mo><mn>0.0007</mn></math> in <math display="inline"><msubsup><mi>N</mi><mi>eff</mi><mrow><mi>SM</mi></mrow></msubsup></math>. This next-to-leading-order QED correction to the interaction rates, together with finite-temperature QED corrections to the electromagnetic density of the plasma, and the effect of neutrino oscillations, implies that <math display="inline"><msubsup><mi>N</mi><mi>eff</mi><mrow><mi>SM</mi></mrow></msubsup><mo>=</mo><mn>3.043</mn></math> with a theoretical uncertainty that is much smaller than any projected observational sensitivity.
002861697 520__ $$9arXiv$$aThe effective number of relativistic neutrino species is a fundamental probe of the early Universe and its measurement represents a key constraint on many scenarios beyond the Standard Model of Particle Physics. In light of this, an accurate prediction of $N_{\rm eff}$ in the Standard Model is of pivotal importance. In this work, we consider the last ingredient needed to accurately calculate $N_{\rm eff}^{\rm SM}$: standard zero and finite temperature QED corrections to $e^+e^- \leftrightarrow \nu\bar{\nu}$ interaction rates during neutrino decoupling at temperatures around $T\sim {\rm MeV}$. We find that this effect leads to a reduction of $-0.0007$ in $N_{\rm eff}^{\rm SM}$. This NLO QED correction to the interaction rates, together with finite temperature QED corrections to the electromagnetic density of the plasma, and the effect of neutrino oscillations, implies that $N_{\rm eff}^{\rm SM} = 3.043$ with a theoretical uncertainty that is much smaller than any projected observational sensitivity.
002861697 540__ $$3preprint$$aarXiv nonexclusive-distrib 1.0$$uhttp://arxiv.org/licenses/nonexclusive-distrib/1.0/
002861697 540__ $$3publication$$aCC BY 4.0$$fSCOAP3$$uhttps://creativecommons.org/licenses/by/4.0/
002861697 542__ $$3publication$$dauthors$$g2023
002861697 595__ $$aCERN-TH
002861697 65017 $$2arXiv$$aastro-ph.CO
002861697 65017 $$2SzGeCERN$$aAstrophysics and Astronomy
002861697 65017 $$2arXiv$$ahep-ph
002861697 65017 $$2SzGeCERN$$aParticle Physics - Phenomenology
002861697 690C_ $$aCERN
002861697 690C_ $$aARTICLE
002861697 700__ $$aEscudero, Miguel$$jORCID:0000-0002-4487-8742$$uCERN$$vTheoretical Physics Department, CERN, 1211 Geneva 23, Switzerland
002861697 700__ $$aMangano, Gianpiero$$jORCID:0000-0002-6901-4633$$uINFN, Naples$$uNaples U.$$vDipartimento di Fisica E. Pancini, Naples, and INFN, Sezione di Napoli, Monte S. Angelo I-80126 Naples, Italy
002861697 700__ $$aPisanti, Ofelia$$uINFN, Naples$$uNaples U.$$vDipartimento di Fisica E. Pancini, Naples, and INFN, Sezione di Napoli, Monte S. Angelo I-80126 Naples, Italy
002861697 773__ $$cL121301$$mpublication$$n12$$pPhys. Rev. D$$v108$$y2023
002861697 8564_ $$82457692$$s695580$$uhttp://cds.cern.ch/record/2861697/files/2306.05460.pdf$$yFulltext
002861697 8564_ $$82457693$$s10374$$uhttp://cds.cern.ch/record/2861697/files/Cartoon.png$$y00000 Born diagram for $e^+e^-\to \bar{\nu} \nu$ annihilations and NLO QED corrections to the $e^+e^-\to \bar{\nu} \nu$ process, including processes contributing to: 1) electron mass and wave function renormalization, 2) electromagnetic vertex correction, and 3) photon emission and absorption.
002861697 8564_ $$82457694$$s15429$$uhttp://cds.cern.ch/record/2861697/files/NLO_Rate.png$$y00001 The relative difference in the $e^+e^-\to \bar{\nu}\nu$ energy transfer rate between the NLO QED and Born scenarios as a function of temperature as calculated in this study. In grey, we highlight the approximate epoch at which neutrinos decouple in the early Universe.
002861697 8564_ $$82501502$$s474040$$uhttp://cds.cern.ch/record/2861697/files/Publication.pdf$$yFulltext
002861697 960__ $$a13
002861697 980__ $$aARTICLE