Theoretical physicists find Higgs boson does not seem to contain any harbingers of new physics

The Higgs boson was discovered in detectors at the Large Hadron Collider about ten years ago. It has proven to be an extremely difficult particle to produce and observe, and despite the passage of time, its properties have still not been understood with sufficient accuracy. Results just published by an international group of theoretical physicists, with the participation of the Institute of Nuclear Physics of the Polish Academy of Sciences, have shed a little light on the origin of the Higgs boson.

This study Published In the journal Physics Review Letter.

The scientific community unanimously considers the greatest discovery from the Large Hadron Collider (LHC) to be the famous Higgs boson. For 12 years, physicists have been trying to determine the properties of this crucial elementary particle as precisely as possible, a task that is extremely difficult due to both experimental challenges and numerous computational hurdles.

Fortunately, Theoretical studiesThe result was made possible through a collaboration between a group of physicists from the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN) in Krakow, the RWTH Aachen University of Technology in Aachen and the Max Planck Institute for Physics (MPI) in Garching near Munich.

The Standard Model is a complex theoretical construct that was constructed in the 1970s and is the basis for the theory as we know it today. Elementary particles The interaction of matter (quarks, electrons, muons, tau, and the associated neutrino trinity) with the electromagnetic force (photons) and the nuclear force (gluons in the strong interaction, and W and Z bosons in the weak interaction).

The greatest achievement in the creation of the Standard Model was the LHC’s discovery of the Higgs boson, a particle that plays a key role in the mechanism that gives other elementary particles mass. The discovery of the Higgs was announced in mid-2012, and since then scientists have been trying to learn as much as possible about this fundamentally important particle.

“For a physicist, one of the most important parameters associated with any elementary or nuclear particle is cross section “The theoretical determination of the cross section of the Higgs particle for a specific collision is of great importance, since it gives information about how frequently the particle appears in a certain type of collision. We have focused on the theoretical determination of the cross section of the Higgs particle in gluon-gluon collisions, which are responsible for around 90% of Higgs productions and whose signatures are recorded in the detectors of the LHC accelerator”, explains Dr. René Ponceret (IFJ PAN).

“The essence of our work was the desire to take into account certain corrections that are usually ignored due to their seemingly small contribution when determining the effective cross section for Higgs particle production, because ignoring them significantly simplifies the calculations. This is the first time that we have succeeded in overcoming mathematical difficulties and determining these corrections,” adds co-author of the paper, Professor Michal Chacón (RWTH).

The importance of the role that higher-order corrections play in understanding the properties of the Higgs particle can be seen from the fact that the second-order corrections calculated in the paper, although seemingly small, account for almost one-fifth of the sought-for effective cross section value, compared to 3% for the third-order correction (although this reduces the uncertainty in the calculation to only 1%).

The novelty of this work was taking into account the effect of the bottom quark’s mass, which led to a small but significant change of about 1%. At this point, it’s worth recalling that the LHC collides protons, particles made of two up quarks and one down quark. The temporary presence of massive quarks inside protons, such as the beauty quark, is a consequence of the quantum nature of the strong interaction that binds quarks together inside the proton.

“The value of the effective cross section for Higgs particle production found by our group is practically the same as that measured in previous beam collisions at the LHC – naturally, taking into account the current imprecision of calculations and measurements. Thus, at least for now, there do not appear to be any precursors to new physics within the mechanism responsible for the formation of the Higgs particle that we are investigating,” Dr. Poncere summarises his team’s research.

The widespread belief among scientists that new physics is necessary stems from the fact that many fundamentally important questions remain unanswered by the Standard Model: Why do elementary particles have mass? Why do they form families? Dark matter What is matter made of, whose traces are so clearly visible in the universe? Why does matter predominate over antimatter in the universe? The Standard Model also needs to be extended, as it does not take into account any of the very common interaction: gravity.

It is important to note that the latest results of theoretical physicists from IFJ PAN, RWTH and MPI do not conclusively deny the existence of new physics in the phenomena associated with the birth of the Higgs particle. A lot can change when data from the gradually starting fourth research cycle of the Large Hadron Collider start to be analyzed.

Increasing the number of collisions of the new particle could narrow the measurement uncertainty and cause the measured range of allowed cross sections for Higgs boson production to no longer match the range defined by theory. Physicists will know in a few years whether this happens.

For now, the Standard Model feels safer than ever, and this fact is slowly becoming the LHC’s most surprising discovery.