تقرير
Neff in the Standard Model at NLO is 3.043
| العنوان: | Neff in the Standard Model at NLO is 3.043 |
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| المؤلفون: | Cielo, Mattia, Escudero, Miguel, Mangano, Gianpiero, Pisanti, Ofelia |
| سنة النشر: | 2023 |
| المجموعة: | Astrophysics High Energy Physics - Phenomenology |
| مصطلحات موضوعية: | High Energy Physics - Phenomenology, Astrophysics - Cosmology and Nongalactic Astrophysics |
| الوصف: | The 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. Comment: 4 pages, 2 figures. v2: Added a paragraph discussing electroweak corrections and other processes at O(alpha). v3: matches published version. References added, typos fixed |
| نوع الوثيقة: | Working Paper |
| URL الوصول: | http://arxiv.org/abs/2306.05460 |
| رقم الأكسشن: | edsarx.2306.05460 |
| قاعدة البيانات: | arXiv |
| الوصف غير متاح. |