New twist on excited dark matter: Implications for INTEGRAL, PAMELA/ATIC/PPB-BETS, DAMA
Bibliographic record
Abstract
We show that the 511 keV gamma ray excess observed by INTEGRAL/SPI can be more robustly explained by exciting dark matter (DM) at the center of the galaxy, if there is a peculiar spectrum of DM states ${\ensuremath{\chi}}_{0}$, ${\ensuremath{\chi}}_{1}$, and ${\ensuremath{\chi}}_{2}$, with masses ${M}_{0}\ensuremath{\sim}500\text{ }\text{ }\mathrm{GeV}$, ${M}_{1}\ensuremath{\lesssim}{M}_{0}+2{m}_{e}$, and ${M}_{2}={M}_{1}+\ensuremath{\delta}M\ensuremath{\gtrsim}{M}_{0}+2{m}_{e}$. The small mass splitting $\ensuremath{\delta}M$ should be $\ensuremath{\lesssim}100\text{ }\text{ }\mathrm{keV}$. In addition, we require at least two new gauge bosons (preferably three), with masses $\ensuremath{\sim}100\text{ }\text{ }\mathrm{MeV}$. With this spectrum, ${\ensuremath{\chi}}_{1}$ is stable but can be excited to ${\ensuremath{\chi}}_{2}$ by low-velocity DM scatterings near the Galactic center, which are Sommerfeld-enhanced by two of the 100 MeV gauge boson exchanges. The excited state ${\ensuremath{\chi}}_{2}$ decays to ${\ensuremath{\chi}}_{0}$ and nonrelativistic ${e}^{+}{e}^{\ensuremath{-}}$, mediated by the third gauge boson, which mixes with the photon and $Z$. Although such a small 100 keV splitting has been independently proposed for explaining the DAMA annual modulation through the inelastic DM mechanism, the need for stability of ${\ensuremath{\chi}}_{1}$ (and hence sequestering it from the standard model) implies that our scenario cannot account for the DAMA signal. It can, however, address the PAMELA/ATIC positron excess via DM annihilation in the galaxy, and it offers the possibility of a sharper feature in the ATIC spectrum relative to previously proposed models. The data are consistent with three new gauge bosons, whose couplings fit naturally into a broken SU(2) gauge theory where the DM is a triplet of the SU(2). We propose a simple model in which the SU(2) is broken by new Higgs triplet and 5-plet vacuum expectation values, giving rise to the right spectrum of DM and mixing of one of the new gauge bosons with the photon and $Z$ boson. A coupling of the DM to a heavy ${Z}^{\ensuremath{'}}$ may also be necessary to get the right relic density and PAMELA/ATIC signals.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".