Simplified Models for Dark Matter Searches at the LHC (1506.03116v3)

Abstract: This document outlines a set of simplified models for dark matter and its interactions with Standard Model particles. It is intended to summarize the main characteristics that these simplified models have when applied to dark matter searches at the LHC, and to provide a number of useful expressions for reference. The list of models includes both s-channel and t-channel scenarios. For s-channel, spin-0 and spin-1 mediation is discussed, and also realizations where the Higgs particle provides a portal between the dark and visible sectors. The guiding principles underpinning the proposed simplified models are spelled out, and some suggestions for implementation are presented.

• The paper introduces simplified models for dark matter searches, emphasizing mediator roles and parameter constraints in LHC experiments.
• It systematically categorizes models into s-channel scalar/pseudoscalar, s-channel vector, and t-channel flavored mediators to delineate distinct collider signatures.
• The study provides actionable insights by linking mediator phenomenology with search strategies, unifying collider data with direct and indirect detection efforts.

Simplified Models for Dark Matter Searches at the LHC

The search for dark matter (DM) remains a crucial endeavor in understanding the fundamental constituents of our universe. The paper "Simplified Models for Dark Matter Searches at the LHC" presents a comprehensive framework for investigating DM interactions using the Large Hadron Collider (LHC). This work elaborates on a set of simplified models designed to interpret potential signals of DM, focusing on how these interactions can be studied and constraints derived using collider data.

Overview of Simplified Models

The paper introduces simplified models as an essential tool for DM studies at colliders, offering a middle ground between effective field theories (EFTs) and complete theories like supersymmetry. The key advantage of simplified models lies in their ability to capture the essential phenomenology with a limited number of free parameters, such as masses and couplings, thereby offering a more tractable theoretical framework for LHC analyses.

The paper categorizes simplified models into three primary classes based on the nature of the mediator:

1. s-Channel Scalar and Pseudoscalar Mediators: These models involve scalar and pseudoscalar particles that mediate interactions between DM and Standard Model (SM) fermions. Particular attention is given to the Higgs portal scenario, where the Higgs boson serves as the mediator. The models discuss possible LHC signatures, including invisible Higgs decays and associated missing energy signals involving heavy quarks.
2. s-Channel Vector Mediators: In these models, a new vector particle facilitates DM-SM interactions, typically associated with an extended gauge sector. The paper emphasizes leptophobic scenarios where the vector boson couples predominantly to quarks, minimizing constraints from resonance searches in the leptonic channels. The paper explores bounds from di-jet resonance searches and mono-jet signals, especially emphasizing constraints from LHC Run II.
3. t-Channel Flavored Mediators: These models feature colored scalar mediators and suggest phenomenologies akin to supersymmetric squark searches. The analyses highlight potential co-annihilation effects and emphasize the complementary nature of mono-jet and multi-jet searches to exclude or discover such signatures.

Collider Phenomenology and Beyond

The theoretical groundwork laid out for these simplified models is crucial for interpreting LHC data. The paper provides detailed cross-section calculations and outlines constraints from existing LHC searches. Moreover, it discusses the relation of these collider searches to direct and indirect detection efforts, stressing the complementarity of each approach.

The authors also address the potential shortcomings of simplified models, such as their limited scope compared to full-fledged theories like the MSSM, encouraging ongoing efforts to refine these frameworks with higher-order corrections and more complex parameter spaces.

Implications and Prospective Directions

The paper's framework has significant implications for future DM searches at colliders. The clear specification of parameters within these simplified models allows for a focused experimental program, enhancing the potential for discovery or exclusion of DM candidates. It suggests strategic modifications to existing experimental searches, notably in leveraging new event topologies that may arise from these interactions.

In conclusion, the paper underscores the importance of simplified models in bridging the gap between theoretical constructs and experimental realities. By providing a versatile and practical approach to probing DM at the LHC, this work lays the foundation for more refined searches in future collider runs, potentially unraveling the elusive nature of dark matter. As experimental techniques improve and theoretical models evolve, this line of investigation will continue to be pivotal in the quest to uncover the nature of dark matter and its role in the cosmos.