New bosons: CERN’s anomalies could bring us closer to novel particles

“We review the hints of new physics, called anomalies, that are seen for various interactions as discrepancies between standard-model predictions and experimental measurements,” the study authors note. 

Such anomalies can occur “in both direct high-energy searches for new particles at the Large Hadron Collider at CERN and indirect low-energy precision experiments,” they added. 

Anomalies explain what the Standard Model can’t

In simple words, the Standard Model is like a recipe book for the universe, explaining what the basic ingredients are (particles) and how they stick together or interact (forces). 

It’s one of the most successful theories in physics because it accurately predicts and explains many of the phenomena we observe in the world around us, such as particle collisions, atomic structure, electromagnetic interactions, nuclear reactions, etc.

“However, there are several phenomena that the Standard Model (SM) cannot account for such as dark-matter particles, or non-vanishing neutrino masses, nor does it describe gravity. There must be more to discover, to extend the SM into a full description of nature,” the study authors note.

In order to explore what’s beyond the Standard Model, the study authors observed the decay of multiple lepton particles inside the Large Hadron collider (LHC). 

Leptons are elementary particles that interact using weak forces (such as electromagnetic force) for interaction. They are of two types: charged and neutral. For example, electrons and muons are negatively charged leptons, and neutrinos are neutral leptons.

The results of the decay were different than what was expected as per the Standard Model. For instance, it resulted in the excess release of particles like electrons and muons.

“These anomalies are consistent with new bosons. This could answer why our current understanding of the matter is not working and would open the door to observing new forces in nature,” Andreas Crivellin, study co-author and a theoretical physicist at the University of Zurich, said. 

Anomalies aren’t limited to new bosons

The study authors explain that before the discovery of the Higgs boson and some other major breakthroughs in particle physics, scientists saw indirect signs, like unexpected results that defied existing theories. 

This suggests that anomalies are early signs or hints of an upcoming discovery. “The anomalies can be explained by supplementing the SM with new particles and new interactions — in particular, additional Higgs bosons, new fermions, and new strongly interacting particles,” the study authors said.

For instance, the multi-lepton anomalies described in the current study may lead to the discovery of new bosons. “Data accumulating from the third run of the LHC could establish the existence of some of these new particles,” the study authors added.

Hopefully, further research will confirm these findings and reveal fundamental particles and forces that are still unknown to us.

The study is published in the journal Nature Reviews Physics.