title: Ð Ð¾Ð»Ñ Ð»ÐµÐ¿ÑÐ¾Ð½Ð½Ð¾Ð¹ Ð°ÑÑÐ¸Ð¼ÐµÑÑÐ¸Ð¸ Ð¸ ÑÑÐµÑÐ¸Ð»ÑÐ½ÑÑ Ð½ÐµÐ¹ÑÑÐ¸Ð½Ð¾ Ð² ÑÐ°Ð½Ð½ÐµÐ¹ ÐÑÐµÐ»ÐµÐ½Ð½Ð¾Ð¹
title: Ð²ÑÐ¿ÑÑÐºÐ½Ð°Ñ ÐºÐ²Ð°Ð»Ð¸ÑÐ¸ÐºÐ°ÑÐ¸Ð¾Ð½Ð½Ð°Ñ ÑÐ°Ð±Ð¾ÑÐ° Ð¼Ð°Ð³Ð¸ÑÑÑÐ°
titleType: Subtitle
title: The role of lepton asymmetry and sterile neutrinos in the early Universe
Creators: name: Ð©ÐµÐ¿ÐºÐ¸Ð½, ÐÐ»ÐµÐºÑÐ°Ð½Ð´Ñ
Publisher: name: Ð¡Ð°Ð½ÐºÑ-ÐÐµÑÐµÑÐ±ÑÑÐ³ÑÐºÐ¸Ð¹ Ð¿Ð¾Ð»Ð¸ÑÐµÑÐ½Ð¸ÑÐµÑÐºÐ¸Ð¹ ÑÐ½Ð¸Ð²ÐµÑÑÐ¸ÑÐµÑ ÐÐµÑÑÐ° ÐÐµÐ»Ð¸ÐºÐ¾Ð³Ð¾
Year: 2024
Subjects: ÐÑÐµÐ»ÐµÐ½Ð½Ð°Ñ
ÐÐµÐ¹ÑÑÐ¸Ð½Ð¾
Ð»ÐµÐ¿ÑÐ¾Ð½Ð½Ð°Ñ Ð°ÑÐ¸Ð¼Ð¼ÐµÑÑÐ¸Ñ
lepton asymmetry

description: Ð Ð´Ð°Ð½Ð½Ð¾Ð¹ ÑÐ°Ð±Ð¾ÑÐµ Ð±ÑÐ» Ð¸ÑÑÐ»ÐµÐ´Ð¾Ð²Ð°Ð½ ÑÑÐ´ Ð²Ð¾Ð¿ÑÐ¾ÑÐ¾Ð², ÑÐ²ÑÐ·Ð°Ð½Ð½ÑÑ Ñ Ð²Ð¾Ð·Ð¼Ð¾Ð¶Ð½ÑÐ¼ ÑÑÑÐµÑÑÐ²Ð¾Ð²Ð°Ð½Ð¸ÐµÐ¼ Ð²Ð¾ ÐÑÐµÐ»ÐµÐ½Ð½Ð¾Ð¹ ÑÑÐµÑÐ¸Ð»ÑÐ½ÑÑ Ð½ÐµÐ¹ÑÑÐ¸Ð½Ð¾ Ð¸ Ð»ÐµÐ¿ÑÐ¾Ð½Ð½Ð¾Ð¹ Ð°ÑÐ¸Ð¼Ð¼ÐµÑÑÐ¸Ð¸ Ð°ÐºÑÐ¸Ð²Ð½ÑÑ Ð½ÐµÐ¹ÑÑÐ¸Ð½Ð¾. Ð£ÑÐ¾ÑÐ½ÐµÐ½Ð¾ ÑÐ¾Ð¾ÑÐ½Ð¾ÑÐµÐ½Ð¸Ðµ Ð¼ÐµÐ¶Ð´Ñ Ð»ÐµÐ¿ÑÐ¾Ð½Ð½Ð¾Ð¹ Ð°ÑÐ¸Ð¼Ð¼ÐµÑÑÐ¸ÐµÐ¹ Ð½ÐµÐ¹ÑÑÐ¸Ð½Ð¾, $L_\nu$, Ð¸ ÑÑÑÐµÐºÑÐ¸Ð²Ð½ÑÐ¼ ÑÐ¸ÑÐ»Ð¾Ð¼ Ð´Ð¾Ð¿Ð¾Ð»Ð½Ð¸ÑÐµÐ»ÑÐ½ÑÑ ÑÐ¾ÑÑÐ¾Ð² Ð½ÐµÐ¹ÑÑÐ¸Ð½Ð¾, $\Delta N_{\rm{eff}}$, Ð½ÐµÐ¾Ð±ÑÐ¾Ð´Ð¸Ð¼Ð¾Ðµ Ð´Ð»Ñ ÑÐµÑÐµÐ½Ð¸Ñ Ð¿ÑÐ¾Ð±Ð»ÐµÐ¼Ñ ÑÐ°ÑÑÐ¾Ð³Ð»Ð°ÑÐ¾Ð²Ð°Ð½Ð¸Ñ Ð¿ÑÐµÐ´ÑÐºÐ°Ð·Ð°Ð½Ð¸Ð¹ Ð¼Ð¾Ð´ÐµÐ»Ð¸ ÐÐµÑÐ²Ð¸ÑÐ½Ð¾Ð³Ð¾ ÐÑÐºÐ»ÐµÐ¾ÑÐ¸Ð½ÑÐµÐ·Ð° Ñ ÑÐµÐ·ÑÐ»ÑÑÐ°ÑÐ°Ð¼Ð¸ Ð½Ð°Ð±Ð»ÑÐ´ÐµÐ½Ð¸Ð¹, Ñ ÑÑÑÑÐ¾Ð¼ Ð½Ð¾Ð²ÑÑ Ð´Ð°Ð½Ð½ÑÑ Ð¿Ð¾ ÑÐ°ÑÐ¿ÑÐ¾ÑÑÑÐ°Ð½ÑÐ½Ð½Ð¾ÑÑÐ¸ Ð¿ÐµÑÐ²Ð¸ÑÐ½Ð¾Ð³Ð¾ $^4$He Ð¸ Ð¿Ð¾ ÑÑÐµÐ¿ÐµÐ½Ð¸ ÑÐµÑÐ¼Ð°Ð»Ð¸Ð·Ð°ÑÐ¸Ð¸ Ð»ÑÐ³ÐºÐ¾Ð³Ð¾ ÑÑÐµÑÐ¸Ð»ÑÐ½Ð¾Ð³Ð¾ Ð½ÐµÐ¹ÑÑÐ¸Ð½Ð¾ Ð² ÑÐ°Ð½Ð½ÐµÐ¹ ÐÑÐµÐ»ÐµÐ½Ð½Ð¾Ð¹. Ð£ÑÑÐ°Ð½Ð¾Ð²Ð»ÐµÐ½Ð¾, ÑÑÐ¾ Ð½Ð°Ð»Ð¸ÑÐ¸Ðµ Ð»ÐµÐ³ÐºÐ¸Ñ Ð¿Ð¾Ð»Ð½Ð¾ÑÑÑÑ ÑÐµÑÐ¼Ð°Ð»Ð¸Ð·Ð¾Ð²Ð°Ð½Ð½ÑÑ ÑÑÐµÑÐ¸Ð»ÑÐ½ÑÑ Ð½ÐµÐ¹ÑÑÐ¸Ð½Ð¾ ($\Delta N_{\rm{eff}} = 1$) Ð½Ðµ Ð±ÑÐ´ÐµÑ Ð¿ÑÐ¾ÑÐ¸Ð²Ð¾ÑÐµÑÐ¸ÑÑ Ð½Ð°Ð±Ð»ÑÐ´Ð°ÑÐµÐ»ÑÐ½ÑÐ¼ Ð´Ð°Ð½Ð½ÑÐ¼ Ð¿ÑÐ¸ Ð²ÐµÐ»Ð¸ÑÐ¸Ð½Ðµ Ð»ÐµÐ¿ÑÐ¾Ð½Ð½Ð¾Ð¹ Ð°ÑÐ¸Ð¼Ð¼ÐµÑÑÐ¸Ð¸ $L_\nu \sim 0.04$. ÐÑÐ»Ð° Ð¸ÑÑÐ»ÐµÐ´Ð¾Ð²Ð°Ð½Ð° Ð²Ð¾Ð·Ð¼Ð¾Ð¶Ð½Ð¾ÑÑÑ Ð³ÐµÐ½ÐµÑÐ°ÑÐ¸Ð¸ Ð»ÐµÐ¿ÑÐ¾Ð½Ð½Ð¾Ð¹ Ð°ÑÐ¸Ð¼Ð¼ÐµÑÑÐ¸Ð¸ Ð´Ð¾ ÑÐ¿Ð¾ÑÐ¸ ÐÐµÑÐ²Ð¸ÑÐ½Ð¾Ð³Ð¾ ÐÑÐºÐ»ÐµÐ¾ÑÐ¸Ð½ÑÐµÐ·Ð°. ÐÐ¾ÐºÐ°Ð·Ð°Ð½Ð¾, ÑÑÐ¾ Ð½ÐµÐ¾Ð±ÑÐ¾Ð´Ð¸Ð¼Ð¾Ð¹ Ð²ÐµÐ»Ð¸ÑÐ¸Ð½Ñ Ð»ÐµÐ¿ÑÐ¾Ð½Ð½Ð°Ñ Ð°ÑÐ¸Ð¼Ð¼ÐµÑÑÐ¸Ñ Ð¼Ð¾Ð¶ÐµÑ Ð±ÑÑÑ ÑÐ³ÐµÐ½ÐµÑÐ¸ÑÐ¾Ð²Ð°Ð½Ð° ÑÐµÑÐµÐ· ÑÐµÐ·Ð¾Ð½Ð°Ð½ÑÐ½ÑÐµ Ð¾ÑÑÐ¸Ð»Ð»ÑÑÐ¸Ð¸ Ð°ÐºÑÐ¸Ð²Ð½ÑÑ Ð½ÐµÐ¹ÑÑÐ¸Ð½Ð¾ ÑÐ¾ ÑÑÐµÑÐ¸Ð»ÑÐ½ÑÐ¼Ð¸ Ð¿ÑÐ¸ ÑÐ¸ÑÐ¾ÐºÐ¾Ð¼ Ð´Ð¸Ð°Ð¿Ð°Ð·Ð¾Ð½Ðµ Ð¿Ð°ÑÐ°Ð¼ÐµÑÑÐ¾Ð² Ð¾ÑÑÐ¸Ð»Ð»ÑÑÐ¸Ð¹. Ð ÑÐ²ÑÐ·Ð¸ Ñ Ð²Ð¾Ð·Ð¼Ð¾Ð¶Ð½ÑÐ¼ ÑÑÑÐµÑÑÐ²Ð¾Ð²Ð°Ð½Ð¸ÐµÐ¼ ÑÑÐ¶ÑÐ»ÑÑ ÑÑÐµÑÐ¸Ð»ÑÐ½ÑÑ Ð½ÐµÐ¹ÑÑÐ¸Ð½Ð¾, Ð±ÑÐ»Ð¾ Ð¸Ð·ÑÑÐµÐ½Ð¾ Ð²Ð»Ð¸ÑÐ½Ð¸Ðµ Ð¸Ñ ÑÐ°ÑÐ¿Ð°Ð´Ð° Ð½Ð° Ð¿Ð°ÑÐ°Ð¼ÐµÑÑ $\Delta N_{\rm{eff}}$ Ð¸ Ð´Ð¸Ð½Ð°Ð¼Ð¸ÐºÑ ÑÐ°ÑÑÐ¸ÑÐµÐ½Ð¸Ñ ÐÑÐµÐ»ÐµÐ½Ð½Ð¾Ð¹. ÐÑÐ¸ Ð¾Ð¿ÑÐµÐ´ÐµÐ»ÑÐ½Ð½Ð¾Ð¼ Ð²ÑÐ±Ð¾ÑÐµ Ð¿Ð°ÑÐ°Ð¼ÐµÑÑÐ¾Ð² Ð¾ÑÑÐ¸Ð»Ð»ÑÑÐ¸Ð¹ ÑÑÐ¶ÑÐ»ÑÑ ÑÑÐµÑÐ¸Ð»ÑÐ½ÑÑ Ð½ÐµÐ¹ÑÑÐ¸Ð½Ð¾ Ñ Ð°ÐºÑÐ¸Ð²Ð½ÑÐ¼Ð¸ $\Delta N_{\rm{eff}}$ Ð´Ð¾ÑÑÐ¸Ð³Ð°ÐµÑ Ð½ÐµÐ¾Ð±ÑÐ¾Ð´Ð¸Ð¼Ð¾Ð³Ð¾ Ð·Ð½Ð°ÑÐµÐ½Ð¸Ñ Ð´Ð»Ñ Ð²Ð¾Ð·Ð¼Ð¾Ð¶Ð½Ð¾Ð³Ð¾ Ð¾Ð±ÑÑÑÐ½ÐµÐ½Ð¸Ñ Ð¸Ð·Ð²ÐµÑÑÐ½Ð¾Ð¹ Ð¿ÑÐ¾Ð±Ð»ÐµÐ¼Ñ $H_0$-tension.
description: In this work, a number of problems related to the presence of sterile neutrinos and the lepton asymmetry of active neutrinos in the Universe was investigated. The necessary value of the neutrino lepton asymmetry, $L_\nu$, and effective number of additional neutrino flavours, $\Delta N_{\rm{eff}}$, to solve the problem of discrepancy between the predictions of the Primordial Nucleosynthesis theory and the observational results was clarified, taking into account new data on the abundance of primordial $^4$He and on the thermalization of light sterile neutrinos in the early Universe. It was found that the presence of light fully thermalized ($\Delta N_{\rm{eff}} = 1$) sterile neutrinos do not contradict the observational data at a value of $L_\nu \sim 0.04$. The possibility of generating such a value of lepton asymmetry before the epoch of the Primordial Nucleosynthesis was investigated. It was shown that such a value of lepton asymmetry can be generated by the resonance oscillations of active neutrinos with sterile ones within a wide range of oscillation parameters. The effect of the possible decay of heavy sterile neutrinos on the parameter $\Delta N_{\rm{eff}}$ and the dynamics of the expansion of the Universe was also studied. At a certain choice of oscillation parameters of heavy sterile neutrinos with active ones $\Delta N_{\rm{eff}}$ reaches the necessary value to explain the well-known $H_0$-tension problem.