CMS employed machine learning to probe rare Higgs decays into charm quarks. The search produced the most stringent limits so far.
The Higgs boson, first observed at the Large Hadron Collider (LHC) in 2012, is a cornerstone of the Standard Model of particle physics.
Through its interactions, it gives fundamental particles such as quarks their mass. Interactions between the Higgs boson and the heaviest “third-generation” quarks—the top and bottom quarks—have already been confirmed and shown to align with Standard Model predictions.
However, studying how the Higgs couples to lighter quarks remains much more difficult. Its interactions with “second-generation” quarks, like the charm quark, and “first-generation” quarks, the up and down quarks that form the nuclei of atoms, are still largely untested. This leaves open the key question of whether the Higgs boson is responsible for giving mass to the very quarks that make up everyday matter.
CMS reports first charm decay search
To explore these interactions, physicists examine how the Higgs boson decays into other particles or is produced alongside them in high-energy proton–proton collisions at the LHC. At a recent CERN seminar, the CMS collaboration presented the first search for a Higgs boson decaying into two charm quarks in events where the Higgs is produced together with a pair of top quarks. By applying advanced artificial intelligence methods, the team achieved the strongest limits so far on the strength of the Higgs boson’s interaction with the charm quark.
Producing a Higgs boson along with a top-quark pair, and then observing it decay into two quarks, is both an uncommon event at the LHC and one that is especially challenging to identify. Quarks almost instantly generate narrow sprays of hadrons, called “jets,” which travel only a short distance before decaying further. This makes it very hard to separate jets that originate from charm quarks in Higgs decays from those created by other quark types. Conventional jet identification techniques, known as “tagging,” are not efficient at recognizing charm jets, driving the need for more sophisticated approaches to improve discrimination.
“This search required a paradigm shift in analysis techniques,” explains Sebastian Wuchterl, a research fellow at CERN. “Because charm quarks are harder to tag than bottom quarks, we relied on cutting-edge machine-learning techniques to separate the signal from backgrounds.”
Neural networks for jet recognition
The CMS team addressed two central challenges by applying machine-learning techniques. The first involved detecting charm jets, which they approached using a graph neural network specifically designed for this task. The second challenge was separating genuine Higgs boson events from background collisions, handled with a transformer network—the same family of models that underlies ChatGPT, but here adapted to classify particle events rather than generate text. To train the charm-tagging system, researchers used hundreds of millions of simulated jets, enabling the algorithm to identify charm jets with much greater precision.
Using data collected from 2016 to 2018, combined with the results from previous searches for the decay of the Higgs boson into charm quarks via other processes, the CMS team set the most stringent limits yet on the interaction between the Higgs boson and the charm quark, reporting an improvement of around 35% compared to previous constraints. This places significant bounds on potential deviations from the Standard Model prediction.
Next steps at the LHC
“Our findings mark a major step,” says Jan van der Linden, a postdoctoral researcher at Ghent University. “With more data from upcoming LHC runs and improved analysis techniques, we may gain direct insight into the Higgs boson’s interaction with charm quarks at the LHC—a task that was thought impossible a few years ago.”
As the LHC continues to collect data, refinements in charm tagging and Higgs boson event classification could eventually allow CMS, and its companion experiment ATLAS, to confirm the Higgs boson’s decay into charm quarks. This would be a major step towards a complete understanding of the Higgs boson’s role in the generation of mass for all quarks and provide a crucial test of the 50-year-old Standard Model.
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4 Comments
The Higgs boson, first observed at the Large Hadron Collider (LHC) in 2012, is a cornerstone of the Standard Model of particle physics.
VERY GOOD!
Please ask researchers to think deeply:
1. What did you observe in your research?
2. What did you not observe in your research?
3. Is there a correlation between what you observed in your research and what you did not observe?
An entire generation has been severely misled, poisoned and fooled by so-called peer-reviewed publications. In today’s physics, the so-called peer-reviewed journals—including Physical Review Letters, Nature, Science, and others—stubbornly insist on and promote the following:
1. Even though θ and τ particles exhibit differences in experiments, physics can claim they are the same particle. This is science.
2. Even though topological vortices and antivortices have identical structures and opposite rotational directions, physics can define their structures and directions as entirely different. This is science.
3. Even though two sets of cobalt-60 rotate in opposite directions and experiments reveal asymmetry, physics can still define them as mirror images of each other. This is science.
4. Even though vortex structures are ubiquitous—from cosmic accretion disks to particle spins—physics must insist that vortex structures do not exist and require verification. Only the particles that like God, Demonic, or Angelic are the most fundamental structures of the universe. This is science.
5. Even though everything occupies space and maintains its existence in time, physics must still debate and insist on whether space exists and whether time is a figment of the human mind. This is science.
6. Even though space, with its non-stick, incompressible, and isotropic characteristics, provides a solid foundation for the development of physics, physics must still insist that the ideal fluid properties of space do not exist. This is science.
And so on.
The so-called peer-reviewed journals—including Physical Review Letters, Nature, Science, and others openly define differences as sameness, sameness as differences, existence as nonexistence, and nonexistence as existence—all while deceiving and fooling the public with so-called “impact factors (IF),” never knowing what shame is.
The universe is not a God, nor is it merely Particles. Moreover, it is not Algebra, Formulas, or Fractions. The universe is the superposition, deflection, entanglement, and locking of spacetime vortex geometries, the interaction and balance of topological vortices and their fractal structures. Topological invariants are the identical intrinsic properties between two isomorphic topological spaces. Different civilizations may create distinct mathematical codes or tools to describe the universality and specificity of these topological invariants under different physical laws.
Mathematics is a formal science, not a natural science. Certain aspects and interactions within space-time vortices and their fractal structures cannot be explained by existing mathematical methods because we have not yet developed a complete mathematical framework. Purportedly ‘peer-reviewed’ publications (including Physical Review Letters, Nature, Science, etc.) are ideologically outdated and entrenched in vested interests. They remain complacent within their insular circles, wholly divorced from notions of sordidness, ugliness, and shame. Your act and comment is one of the greatest contributions of these so-called peer-reviewed publications to society.
Topology provides stability blueprints, but specific physics (spatial features, gravitational collapse, fluid viscosity, quantum measurement) dictates vortex generation, evolution, and decay. If researchers are interested in this, please visit https://zhuanlan.zhihu.com/p/1933484562941457487 and https://zhuanlan.zhihu.com/p/1925124100134790589.
Countless pseudoscientific studies and papers have been shocking.
Philosopher Thomas Kuhn in The Structure of Scientific Revolutions noted science often progresses through “paradigm shifts” with incommensurability between old and new paradigms. Through Topological Vortex Theory (TVT), human cognition of nature’s essence is undergoing a profound shift from “universal gravitation” to “universal spin.” This transition not only addresses old theory limitations but philosophically reshapes our cosmic view.
If researchers are interested in this, please visit https://zhuanlan.zhihu.com/p/1943715764965188178.
You’re going to find that your sacred cows, aren’t there. ( surprise! )