International Joint Workshop on the Standard Model and Beyond 2024 & 3rd Gordon Godfrey Workshop on Astroparticle Physics

New 511 keV Line Data Provide Strongest Sub-GeV Dark Matter Constraints

12 Dec 2024, 15:30

20m

202 (Ainsworth Building)

Contributed Talk Light and ultralight physics

Speaker

Shyam Balaji (LPTHE)

Description

We explore the $511$~keV emission associated to sub-GeV dark matter (DM) particles that can produce electron-positron pairs and form positronium after thermalizing. We use $\sim 16$~yr of SPI data from INTEGRAL to constrain DM properties, including the full positron propagation and losses, and the free electron density suppression away from the Galactic plane. We show that the predicted longitude and latitude profiles vary significantly for different DM masses, unlike previous assumptions, and obtain the strongest limits on sub-GeV DM (from the MeV to a few GeV) so far, excluding cross-sections down to $⟨\sigma v⟩\lesssim {10}^{-32}$ cm${}^3$ s${}^{-1}$ for $m_{\chi }\sim 1\text{MeV}$ and $⟨\sigma v⟩\lesssim {10}^{-26}$ cm${}^3$ s${}^{-1}$ for $m_{\chi }\sim 5\text{GeV}$ and lifetimes up to $\tau \gtrsim {10}^{29}\text{s}$ for $m_{\chi }\sim 1\text{MeV}$ and $\tau \gtrsim {10}^{27}\text{s}$ for $m_{\chi }\sim 5$~GeV for the typical Navarro-Frenk-White DM profile. Our derived limits are robust within a factor of a few due to systematic uncertainties.

Presentation materials

Shyam_Syd_talk.pdf