Scientists have achieved the highest degree of precision ever in measuring the strong force, which binds together the particles that make up protons and neutrons. The strong force is the most powerful of all the fundamental forces of nature, but its strength is more uncertain compared to the others. Accurate measurement of the strong force is crucial for understanding the nature of the world around us.
While the other fundamental forces weaken as particles move further apart, the strong force becomes even stronger. This leads to exotic effects that make it difficult to measure directly. Researchers at the CERN particle physics laboratory in Geneva, Switzerland, used the ATLAS experiment at the Large Hadron Collider (LHC) to significantly improve the precision of the measurement. They reduced the relative uncertainty in the force’s strength to 0.8 percent, which is an improvement of 2 to 3 times compared to previous measurements.
The measurement was made by colliding pairs of protons, which produced a particle known as a Z boson. The presence of the strong force caused a small “kick” to the Z boson, altering its momentum in a way that depends on the strength of the force. The value of the strong force is a major source of uncertainty in the standard model of particle physics, and it plays a crucial role in predictions made by the LHC.
Besides its importance in particle physics, the strong force also influences our understanding of the fate of the universe. There is a possibility that the universe could end through a phenomenon called vacuum decay, in which a quantum fluctuation produces a small bubble of unusual space-time called pure vacuum. The probability of this happening is low but uncertain, and the value of the strong force contributes to that uncertainty.
Although this new measurement represents a significant achievement, our knowledge of the strong force still lags behind the precise calculations of other fundamental forces. The measurement of the strong force is extremely challenging, and it is unlikely that we will reach the same level of exactness in the near future. However, there are proposals for a new collider at CERN that would specialize in studying the Z boson, which may lead to further advancements in precision.
