Dark matter is a critical component of the universe, with evidence suggesting it constitutes about a quarter of the universe's total energy density. While dark matter's gravitational effects are well understood, its composition remains unknown. This review explores various dark matter candidates motivated by particle physics, including WIMPs, superWIMPs, light gravitinos, hidden dark matter, sterile neutrinos, and axions. These candidates are evaluated based on their particle physics motivations, production mechanisms, and implications for detection methods such as direct and indirect detection, particle colliders, and astrophysical observations.
The Standard Model of particle physics, while successful, has several unresolved issues, including the gauge hierarchy problem, new physics flavor problem, neutrino mass problem, and the strong CP problem. These issues motivate the search for new particles that could explain dark matter. For example, the gauge hierarchy problem suggests new particles at the weak scale, while the neutrino mass problem implies the existence of sterile neutrinos. The strong CP problem is addressed by axions, which are also considered dark matter candidates.
WIMPs, which are weakly interacting massive particles, are the most studied dark matter candidates. They are produced through thermal freeze-out and have the correct relic density to account for dark matter. The WIMP miracle suggests that weak-scale particles are excellent dark matter candidates. However, the stability of WIMPs is crucial, and their interactions with the Standard Model must be efficient enough to produce the observed dark matter density.
Other dark matter candidates include superWIMPs, which are heavier and may be produced through different mechanisms, and light gravitinos, which are the supersymmetric partners of the graviton. Hidden dark matter, which exists in a separate sector from the Standard Model, and sterile neutrinos, which do not interact via the weak force, are also considered. Axions, which are hypothetical particles that solve the strong CP problem, are another candidate.
The review discusses the implications of these candidates for detection methods. Direct detection experiments, such as those searching for dark matter scattering off normal matter, and indirect detection experiments, which look for annihilation products, are key to identifying dark matter. Particle colliders, such as the Large Hadron Collider, may also provide insights into dark matter production and interactions.
The review concludes that while the identity of dark matter remains a mystery, the interplay between particle physics and cosmology offers promising avenues for discovery. Future experiments may confirm or exclude many of these candidates, potentially leading to a new era of understanding the universe at both the largest and smallest scales.Dark matter is a critical component of the universe, with evidence suggesting it constitutes about a quarter of the universe's total energy density. While dark matter's gravitational effects are well understood, its composition remains unknown. This review explores various dark matter candidates motivated by particle physics, including WIMPs, superWIMPs, light gravitinos, hidden dark matter, sterile neutrinos, and axions. These candidates are evaluated based on their particle physics motivations, production mechanisms, and implications for detection methods such as direct and indirect detection, particle colliders, and astrophysical observations.
The Standard Model of particle physics, while successful, has several unresolved issues, including the gauge hierarchy problem, new physics flavor problem, neutrino mass problem, and the strong CP problem. These issues motivate the search for new particles that could explain dark matter. For example, the gauge hierarchy problem suggests new particles at the weak scale, while the neutrino mass problem implies the existence of sterile neutrinos. The strong CP problem is addressed by axions, which are also considered dark matter candidates.
WIMPs, which are weakly interacting massive particles, are the most studied dark matter candidates. They are produced through thermal freeze-out and have the correct relic density to account for dark matter. The WIMP miracle suggests that weak-scale particles are excellent dark matter candidates. However, the stability of WIMPs is crucial, and their interactions with the Standard Model must be efficient enough to produce the observed dark matter density.
Other dark matter candidates include superWIMPs, which are heavier and may be produced through different mechanisms, and light gravitinos, which are the supersymmetric partners of the graviton. Hidden dark matter, which exists in a separate sector from the Standard Model, and sterile neutrinos, which do not interact via the weak force, are also considered. Axions, which are hypothetical particles that solve the strong CP problem, are another candidate.
The review discusses the implications of these candidates for detection methods. Direct detection experiments, such as those searching for dark matter scattering off normal matter, and indirect detection experiments, which look for annihilation products, are key to identifying dark matter. Particle colliders, such as the Large Hadron Collider, may also provide insights into dark matter production and interactions.
The review concludes that while the identity of dark matter remains a mystery, the interplay between particle physics and cosmology offers promising avenues for discovery. Future experiments may confirm or exclude many of these candidates, potentially leading to a new era of understanding the universe at both the largest and smallest scales.