Physicists at CERN say they have measured the lifespan of the Higgs boson more accurately than ever before. For their work, the researchers fell back on a creative workaround.
Theorized in the mid-1960s by physicist Peter Higgs, the Higgs boson (which therefore bears his name) was finally revealed in 2012. Then imagine a particle. Particles are made up of atoms, which are themselves made up of protons and neutrons. Break them down, and you find elementary particles. In other words, at the end of this game of Russian dolls, you can't make it smaller. The Higgs boson is one of these elementary particles. It should also be understood that these bosons are in the form of a "field" uniformly lining the entire cosmos.
To better understand, let's take the example of a carpet of snow that is perfectly identical at every point in the universe. The Higgs boson here would be the flake that makes up this carpet. Then imagine a skier tumbling down at breakneck speed. It then does not have time to sink and therefore leaves no trace. This skier could for example be the photon that makes up light. A photon evolves so quickly that it does not interact with the Higgs field. It does not "sink" and therefore does not gain mass. The more a particle interacts with the Higgs field, the more mass it acquires.
In summary, the Higgs boson is therefore an elementary particle that makes up the Higgs field, whose interaction with other particles determines their mass. Its importance is such thatwithout it, there would be no matter . Its detection in 2012 was thus considered one of the most important scientific breakthroughs of a century.
Since 2012, the Higgs boson has been regularly produced in the Large Hadron Collider (LHC), which has allowed physicists to study its properties. However, some of them are still difficult to pin down due to its short lifespan (a few seven-millionths of a second). Beyond that, the Higgs boson decays into other particles. Moreover, its lifetime is itself one of the most difficult properties to measure directly . This brings us back to this new study.
In an attempt to precisely measure the lifetime of the Higgs boson, researchers at CERN relied on an indirect method, focusing on its mass width; the range of possible masses the particle can have. The wider the mass width of a particle, the shorter its lifetime, allowing physicists to calculate the latter by measuring the former.
The nominal mass of the Higgs boson (its usual and most common value) is 125 gigaelectronvolts (GeV) . However, thanks to the strangeness of the Heisenberg uncertainty principle, it can happen that versions with larger masses are also produced.
As part of this study, the researchers calculated the ratio of Higgs bosons close to their nominal mass and those with a mass much larger than usual. Based on this technique, they now determine that the lifetime of the Higgs boson is 210 yoctoseconds, that is to say of the order of a seven-millionth of a second (a decimal point followed by 22 zeros ).
The uncertainty of this value is (+2.3/-0.9) x 10^-22 seconds, making it the most accurate measurement of the lifetime of the Higgs boson to date . This new work therefore marks an important step in the study of the properties of this unique particle.
