Gamma-ray limits on neutrino lines from dark matter annihilations

0.1 1 10 100

Dark Matter Mass [TeV]

1e-24 1e-23 1e-22

σv [cm3 /s]

χχ −> ν

α

_ να

Fermi (e,µ) Fermi (τ)

HESS (e, µ)

HESS ( τ) IceCube GC

IceCube Dwarfs

SuperK GC

CTA (e, µ)

CTA ( τ)

α = e, µ, τ

Gamma-ray limits on neutrino lines from dark matter annihilations

Based on 1602.05966 (JCAP) with F. Queiroz and C. Weniger

Carlos E. Yaguna

Max-Planck-Institute for Nuclear Physics Heidelberg, Germany

2016

How strongly?

What’s the mediator?

Ω_DM ∝ 1/hσvi

Φ_γ,ν,e+,p¯ ∝ hσvi

The annihilation rate into SM fields is a basic property of the dark matter particle

It hints at how the dm particle interacts

It determines the relic density via freeze-out

It gives rise to indirect detection signals

hσvi_total < hσvi_νν¯ Beacom et al, 2007

E_ν = M_DM

Z⁰, Leptophilic, DM-ν ^masses

The

final state sets an upper bound on the total dm annihilation rate into SM fields

Because ν’s are the least detectable particles

It gives rise to a line in the ν ^spectrum

Many dm models feature such a final state

100 1000 10000 1e+05

Dark Matter Mass [GeV]

1e-24 1e-23 1e-22 1e-21 1e-20

σv [cm3 /s]

IceCube GC (NFW) IceCube GC (Burkert) IceCube Dwarfs

Super-K GC (NFW)

χχ −> ν

αν

α

Neutrino experiments already provide some constraints on

From dm annihilation in the GC and dwarfs

What about gamma-ray data?

0.1 1 10 100 1000

Eγ [GeV]

0.01 0.1 1 10 100

E γ dN γ/dE γ

bb WW ν_eν_e νµν

µ

ντν

τ

MDM = 3 TeV

A continuous gamma-ray spectrum is always produced in association with

lines

Induced by electroweak corrections

This spectrum is model-independent

The flux increases with the dm mass

0.1 1 10 100

Dark Matter Mass [TeV]

1e-24 1e-23 1e-22

σv [cm3 /s]

χχ −> ν

α

_ να

Fermi (e,µ) Fermi (τ)

HESS (e, µ)

HESS ( τ) IceCube GC

IceCube Dwarfs

SuperK GC

α = e, µ, τ

Neutrino lines can be indirectly searched for with Fermi-LAT and HESS data

They provide stronger limits above 200 GeV

They may distinguish the ν ^flavor

0.1 1 10 100

Dark Matter Mass [TeV]

1e-24 1e-23 1e-22

σv [cm3 /s]

χχ −> ν

α

_ να

Fermi (e,µ) Fermi (τ)

HESS (e, µ)

HESS ( τ) IceCube GC

IceCube Dwarfs

SuperK GC

CTA (e, µ)

CTA ( τ)

α = e, µ, τ

γ

-ray data already set the most stringent bounds on

lines from dm annihilation

CTA will improve the current limit by . 10

ν detectors will remain valuable at low masses

ν lines will likely be discovered in γ-rays