The physicist with Atlas collaboration We presented our first observations of VVZ production at Cern's large Hadron Collider. This is a rare combination of three giant vector bosons.
Three vector boson events recorded by Atlas are when one W-boson collapses into electrons and neutrinos, one collapses into moons and neutrinos, and two moons collapses into z boson. Muons are shown with a red line, electrons are shown with a green line, and a white line where “loss of energy” from Neutrino is destroyed. Image credits: Atlas/Cern.
As carriers of weak forces, W and Z bosons are central to standard models of particle physics.
Accurate measurements of multiboson production processes provide excellent testing of standard models and shed light on new physical phenomena.
“The production of three vector (V) bosons is a very rare process in LHC,” says Dr. Fabio Cerutti, Ph.D., Atlas Physics Coordinator.
“The measurement provides information about the interactions between multiple bosons linked to the symmetry underlying the standard model.”
“It is a powerful tool to uncover new physics phenomena, such as new particles that are too heavy to be produced directly in LHC.”
The Atlas team observed the generation of VVZ with statistical significance of 6.4 standard deviations, exceeding the five standard deviation thresholds needed to assert the observations.
This observation extends previous results from Atlas and CMS collaborations, including observations of VVV production by CMS and observations of WWW production by Atlas.
As some of the heaviest known particles, W and Z bosons can collapse in countless different ways.
In a new study, Atlas physicists focused on seven attenuation channels with the highest discovery potential.
These channels were further refined using a machine learning technique called Boosted Decision Trees, where the algorithms for each channel were trained to identify the desired signal.
By combining the attenuation channels, researchers were able to observe the production of VVZ and set limits on the contributions of new physical phenomena to the signal.
“The resulting limitations confirm the validity of the standard model and are consistent with previous results on the generation of three vector bosons,” they said.
“Analyzing the third run of LHC and the large dataset from future HLHCs will further improve the measurements of the generation of three vector bosons. We will deepen our understanding of these basic particles and our role in the universe.”
Team's result It will be published in journal Physical character b.
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Atlas collaboration. 2025. Observation of VVZ production at S√=13 TEV using an ATLAS detector. Phys. Rhett. bin press; Arxiv: 2412.15123
Source: www.sci.news
