Dark matter annihilation into right-handed neutrinos and the galactic center gamma-ray excess

In this paper, we will discuss a specific case that the dark matter particles annihilate into right-handed neutrinos. We calculate the predicted gamma-ray excess from the galactic center and compare our results with the data from the Fermi-LAT. An approximately 10-60 GeV right-handed neutrino with heavier dark matter particle can perfectly explain the observed spectrum. The annihilation cross section $\langle \sigma v \rangle$ falls within the range $0.5$-$4 \times 10^{-26} \text{ cm}^3/\text{s}$, which is roughly compatible with the WIMP annihilation cross section.

Introduction to the photon excess from the galactic center ▶ In Ref. arXiv:hep-ph/0508108, a γ-ray excess of 1-10 GeV from near the galactic center was studied in the EGRET era.  Introduction to the photon excess from the galactic center ▶ In order to fit the data from arxiv:1409.0042, Introduction to the photon excess from the galactic center ▶ In order to fit the data from arxiv:1409.0042,

Introduction to the WIMP Dark Matter
▶ Weak Interacting Massive Particles (WIMPs). As the temperature of the universe drops down after the Big Bang, the annihilating dark matter particles finally "freeze-out" when n eq ⟨σv⟩ dec ≈ H.
▶ ⟨σv⟩ dec is calculated to be approximately 2-3 × 10 −26 cm 3 /s, which is said to be "coincide" with the weak interaction strength.

Introduction to the WIMP Dark Matter
▶ Weak Interacting Massive Particles (WIMPs). As the temperature of the universe drops down after the Big Bang, the annihilating dark matter particles finally "freeze-out" when n eq ⟨σv⟩ dec ≈ H.
▶ ⟨σv⟩ dec is calculated to be approximately 2-3 × 10 −26 cm 3 /s, which is said to be "coincide" with the weak interaction strength.

See-saw Mechanisms
▶ Majorana mass among right-handed neutrinos.

See-saw Mechanisms
▶ Majorana mass among right-handed neutrinos.

See-saw Mechanisms
▶ Majorana mass among right-handed neutrinos.

See-saw Mechanisms
▶ Majorana mass among right-handed neutrinos.

Yi-Lei Tang(汤亦蕾)
Dark matter annihilation into right-handed neutrinos and the ga

See-saw Mechanisms
▶ Majorana mass among right-handed neutrinos. . γ spectrum from the N's decay ▶ One light right-handed neutrino for simplicity. In the multi-right-handed neutrino cases, we can only linearly sum over the spectrum by each single right-handed neutrino. . γ spectrum from the N's decay ▶ One light right-handed neutrino for simplicity. In the multi-right-handed neutrino cases, we can only linearly sum over the spectrum by each single right-handed neutrino.
▶ Eqn. (3) can summarize the features of the right-handed neutrinos in most of the right-handed neutrino models. . γ spectrum from the N's decay ▶ One light right-handed neutrino for simplicity. In the multi-right-handed neutrino cases, we can only linearly sum over the spectrum by each single right-handed neutrino.
▶ Eqn. (3) can summarize the features of the right-handed neutrinos in most of the right-handed neutrino models. ▶ After EWSB, . γ spectrum from the N's decay ▶ One light right-handed neutrino for simplicity. In the multi-right-handed neutrino cases, we can only linearly sum over the spectrum by each single right-handed neutrino.
▶ Eqn. (3) can summarize the features of the right-handed neutrinos in most of the right-handed neutrino models. ▶ After EWSB, . γ spectrum from the N's decay ▶ One light right-handed neutrino for simplicity. In the multi-right-handed neutrino cases, we can only linearly sum over the spectrum by each single right-handed neutrino.
▶ Eqn. (3) can summarize the features of the right-handed neutrinos in most of the right-handed neutrino models. ▶ After EWSB, . γ spectrum from the N's decay ▶ For simplicity, we only consider the following two scenarios, ▶ y 1 = y 2 = 0, y 3 ̸ = 0. Then 100% of the right-handed neutrinos decay through τ + W * /ν τ + Z * channels. The tau leptons also contribute to the gamma-ray spectrum; . . γ spectrum from the N's decay ▶ For simplicity, we only consider the following two scenarios, ▶ y 1 = y 2 = 0, y 3 ̸ = 0. Then 100% of the right-handed neutrinos decay through τ + W * /ν τ + Z * channels. The tau leptons also contribute to the gamma-ray spectrum; ▶ y 3 = 0, y 2 1 + y 2 2 ̸ = 0. Since muons and electrons do not produce photons, and the ratios Br(N→νeZ * ) are fixed at a given m N ≫ m µ , the gamma-ray spectrum should be independent on concrete values of y 1,2 . . γ spectrum from the N's decay ▶ For simplicity, we only consider the following two scenarios, ▶ y 1 = y 2 = 0, y 3 ̸ = 0. Then 100% of the right-handed neutrinos decay through τ + W * /ν τ + Z * channels. The tau leptons also contribute to the gamma-ray spectrum; ▶ y 3 = 0, y 2 1 + y 2 2 ̸ = 0. Since muons and electrons do not produce photons, and the ratios Br(N→νeZ * ) are fixed at a given m N ≫ m µ , the gamma-ray spectrum should be independent on concrete values of y 1,2 .
▶ The gamma-ray spectrum by general values of y 1,2,3 are just linear-combinations of the above two cases.