The Tevatron at the Frontier of Dark Matter Direct Detection (1005.3797v2)

Abstract: Direct detection of dark matter (DM) requires an interaction of dark matter particles with nucleons. The same interaction can lead to dark matter pair production at a hadron collider, and with the addition of initial state radiation this may lead to mono-jet signals. Mono-jet searches at the Tevatron can thus place limits on DM direct detection rates. We study these bounds both in the case where there is a contact interaction between DM and the standard model and where there is a mediator kinematically accessible at the Tevatron. We find that in many cases the Tevatron provides the current best limit, particularly for light dark matter, below 5 GeV, and for spin dependent interactions. Non-standard dark matter candidates are also constrained. The introduction of a light mediator significantly weakens the collider bound. A direct detection discovery that is in apparent conflict with mono-jet limits will thus point to a new light state coupling the standard model to the dark sector. Mono-jet searches with more luminosity and including the spectrum shape in the analysis can improve the constraints on DM-nucleon scattering cross section.

• The paper leverages mono-jet signals at the Tevatron to constrain dark matter–nucleon interactions using a model-independent operator analysis.
• It demonstrates that for light dark matter and spin-dependent cases, collider bounds can exceed those from direct detection experiments.
• The study highlights the need for refined collider strategies, such as increased luminosity, to more effectively probe DM interactions with light mediators.

The Tevatron at the Frontier of Dark Matter Direct Detection

The exploration of dark matter (DM) through both direct detection and collider-based approaches remains an active field of research. The paper "The Tevatron at the Frontier of Dark Matter Direct Detection," authored by Bai, Fox, and Harnik, addresses how collider searches, particularly mono-jet signals at the Tevatron, can place constraints on dark matter direct detection rates.

Key Contributions and Methodology

This research leverages the interaction of dark matter particles with nucleons, which is pivotal for direct detection, to evaluate mono-jet signals at the Tevatron. The paper studies both scenarios where dark matter interactions are mediated through contact interactions with the standard model (SM) and scenarios involving a kinematically accessible mediator at the Tevatron. The comparison of these collider-derived bounds with those from conventional direct detection experiments provides insights significant for dark matter detection, particularly for light dark matter (below approximately 5 GeV) and spin-dependent interaction cases.

The authors adopt a model-independent approach by considering operator analyses that account for DM as a fermion influenced by some massive state mediating its interaction with quarks. Notably, they focus on mono-jet searches, aligning theoretical predictions with experimental results to determine constraints on the strength of dark matter quark interactions, represented by parameters such as the mediator mass $M$ and couplings $g_\chi$ and $g_q$.

Numerical Results and Limitations

Through this analysis, the paper establishes that in many circumstances, the Tevatron provides stringent limits on DM interactions. Specifically, for light dark matter particles or scenarios with spin-dependent interactions, the Tevatron's bounds are shown to be more restrictive than those from direct detection experiments like CDMS or XENON. The introduction of light mediators, however, appears to weaken these bounds significantly unless they are in proximity to the energy scales probed by the Tevatron.

The numerical results illustrate that for heavy mediators, with $M \gtrsim 100$ GeV, the collider's sensitivity surpasses direct detection when comparing nuclear recoil exchanges. Conversely, for light mediators, the collider limits are less stringent, illustrating a need for such mediators to alleviate apparent conflicts between collider observations and direct detection data.

Theoretical and Practical Implications

The theoretical implications of this work highlight the importance of collider searches in the broader spectrum of DM detection strategies. Practically, its findings suggest that collider experiments should adapt strategies such as increased luminosity and mono-jet spectral shape analysis to enhance the constraints imposed on DM-nucleon scattering cross-sections. These adjustments could allow future collider experiments, including those at the LHC, to offer even more competitive bounds on potential dark matter candidates.

Moreover, the research hints at a promising direction in detecting non-standard dark matter scenarios. Should direct detections reveal signals at odds with mono-jet constraints, it would suggest the necessity of additional light states that mediate the interactions between the standard model and the dark sector, thus contributing to novel DM models.

Speculations on Future Developments

With advances in collider technology and data collection techniques, the approach elucidated in this paper may result in more refined bounds on various dark matter interactions. Particularly, the application of such methods at higher energy frontiers like the LHC could provide deeper insights and potentially novel discoveries within the field of particle physics and cosmology. The continued integration of collider and direct detection methodologies stands to refine our understanding of dark matter considerably.

In conclusion, the intersection of collider physics and direct detection techniques as explored in this paper presents an intricate path forward in the ongoing effort to uncover the nature of dark matter, demonstrating the significance of collider experiments as a complement to traditional dark matter detection strategies.