Hunting for Higgs Pairs: A New Chapter in Particle Physics
The search for rare events involving multiple Higgs bosons is gaining momentum at CERN, with recent combined data from the ATLAS and CMS experiments offering tantalizing hints. Whereas the existence of two Higgs particles produced in proton-proton collisions is theoretically possible, it’s an incredibly rare occurrence. Combining the datasets from these two major experiments allows physicists to achieve better statistical power in their search.
The Significance of the Higgs Boson
Both ATLAS and CMS famously confirmed the existence of the Higgs boson in 2012. This particle is central to the Standard Model of particle physics, explaining how fundamental particles acquire mass. Since its discovery, the Higgs boson has been the subject of intense scrutiny, particularly to map the shape of its associated potential.
Understanding the interaction between Higgs bosons is crucial. One key question is whether the Higgs potential exhibits structural features at higher energies. These features could potentially indicate that the universe is fundamentally unstable.
First Joint Results: A Hint of Discovery
ATLAS and CMS have recently presented their first joint results in the hunt for double-Higgs events, based on data collected during the LHC’s Run 2 (2015-2018). The combined data reveals tentative evidence for the existence of these paired Higgs bosons. These pairs are primarily expected to arise from the fusion of gluons within colliding protons.
Currently, the statistical significance of the observed signal is 1.1 sigma. In particle physics, a significance of 5 sigma is required for a definitive discovery. However, researchers are optimistic.
“If we already identify a hint in this relatively little dataset, it gives good hope for the experiments with LHC Run-3 that still need to be analyzed,” says Tristan du Pree, a researcher at Nikhef involved in the search for double and even triple Higgs events.
The High-Luminosity LHC: A Future Boost
CERN is currently preparing for the High-Luminosity Large Hadron Collider (HiLumi LHC) project, which will significantly increase the intensity of proton beams. This upgrade, scheduled to be operational by 2030, will deliver roughly an order of magnitude more data than previous runs, dramatically increasing the chances of observing rare events like double Higgs production.
The HiLumi LHC involves the installation of new cryogenic “cold boxes” deep within the LHC tunnel, as part of the upgrade process. This will allow for more frequent and energetic collisions.
CMS and ATLAS: Complementary Approaches
Both the CMS and ATLAS detectors are designed as general-purpose experiments, capable of studying various aspects of proton collisions. While they share the same scientific goals, they employ different technical solutions and system designs. The CMS detector, for example, is built around a large solenoid, while ATLAS utilizes a different magnet system.
What Does This Indicate for Our Understanding of the Universe?
The potential discovery of double Higgs events could provide crucial insights into the nature of the Higgs potential and the stability of the universe. It could also open up new avenues for exploring physics beyond the Standard Model, including the search for dark matter and extra dimensions.
Did you recognize?
The ATLAS detector weighs 7,000 tonnes and is the largest volume particle detector ever constructed.
FAQ
Q: What is the Higgs boson?
A: The Higgs boson is a fundamental particle associated with a field that gives other particles mass.
Q: What is the significance of finding double Higgs events?
A: Observing double Higgs events could reveal information about the shape of the Higgs potential and the stability of the universe.
Q: What is the High-Luminosity LHC?
A: The HiLumi LHC is an upgrade to the LHC that will increase the intensity of proton beams, allowing for more frequent and energetic collisions.
Q: What is the statistical significance needed for a discovery?
A: A statistical significance of 5 sigma is generally required for a definitive discovery in particle physics.
Q: What are the differences between the ATLAS and CMS experiments?
A: Both experiments have the same goals, but they utilize different technical solutions and magnet system designs.
Want to learn more about the cutting edge of particle physics? Explore the ATLAS experiment website or visit the CMS website.
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