Exploring the Mysteries of Dark Matter and Energy at CERN
Written on
Chapter 1: The Quest for Dark Matter and Energy
The pursuit of dark matter and dark energy is intensifying at CERN’s Large Hadron Collider (LHC). Following the successful identification of the Higgs Boson, researchers are now focusing on these two elusive phenomena.
Dark matter and dark energy constitute the vast majority of the universe's composition, yet their presence remains largely theoretical, detected only through their gravitational effects. As LianTao Wang, a physics professor involved in seeking signals in particle accelerators like the LHC, articulates, “We are certain there exists a dark realm, containing more energy than our own.”
Wang and a collaborative team from the University of Chicago and Fermilab have devised a pioneering approach to uncovering dark matter at the LHC by targeting particles that might exhibit slightly reduced speeds.
Section 1.1: Understanding Dark Matter and Energy
Despite dark matter and dark energy accounting for over 95% of the universe, direct observation has been elusive. For instance, dark matter's existence is inferred from its gravitational influence, which prevents galaxies from dispersing.
Subsection 1.1.1: Theoretical Insights into Dark Particles
Theorists speculate the existence of a specific type of dark particle that interacts occasionally with ordinary matter. This particle is hypothesized to be significantly heavier and more enduring—lasting roughly one-tenth of a second—compared to other known particles. Such particles could occasionally become entangled in the frequent collisions of protons that the LHC generates and monitors, though this interaction is extremely rare.
Going Back to the Big Bang: In the Hunt for Dark Matter - This video explores the efforts to trace dark matter back to the origins of the universe, shedding light on its elusive nature.
Section 1.2: The Role of the Higgs Boson
Wang posits that uncovering more about dark matter and energy may be intricately linked to the Higgs Boson, which was discovered in 2012. “One particularly intriguing possibility is that these long-lived dark particles may be connected to the Higgs boson in some way—the Higgs could serve as a gateway to the dark realm,” he explains.
“There’s a chance that the Higgs itself might decay into these long-lived particles.”
However, distinguishing these events from the vast array of other occurrences is a significant challenge. With the LHC executing over a billion collisions every second within its 27-kilometer structure, finding such rare events is akin to searching for a needle in a haystack.
Chapter 2: Innovations in Detection Methods
Wang, along with UChicago postdoctoral fellow Jia Liu and Fermilab scientist Zhen Liu, propose a novel strategy that leverages a specific characteristic of these dark particles. Liu clarifies, “Given their weight, generating such particles requires considerable energy, resulting in lower momentum and slower velocities compared to light.”
This time delay could distinguish dark particles from the myriad of typical particles. Researchers need only adjust their systems to seek particles that are produced and subsequently decay at a pace slightly slower than their counterparts.
The New Hunt for Dark Matter - This video discusses the latest techniques and discoveries in the ongoing search for dark matter, highlighting the importance of innovative methods.
The disparity in speed is minuscule—on the order of a nanosecond or less. Fortunately, the LHC's advanced detectors are already capable of identifying such variations, with recent studies confirming that this method is promising. Additionally, ongoing upgrades to the detectors are expected to enhance their sensitivity.
Liu adds, “We foresee this method significantly improving our ability to detect long-lived dark particles by more than an order of magnitude, utilizing existing capabilities at the LHC.”
Experimental efforts are currently underway to construct the necessary detection apparatus. When the LHC resumes operations in 2021, following a tenfold increase in its luminosity, all three major detectors will implement this innovative approach, according to the scientists involved.
Liu concludes, “We believe this has immense potential for groundbreaking discoveries. If the particle exists, we just need to discover the right questions to ask.”
Original research: Enhancing Long-Lived Particles Searches at the LHC with Precision Timing Information, Jia Liu et al, Physical Review Letters (2019). DOI: 10.1103/PhysRevLett.122.131801