Physicists with the ATLAS Collaboration at CERN’s Massive Hadron Collider have introduced the primary remark of VVZ manufacturing — a uncommon mixture of three huge vector bosons.
A 3-vector-boson occasion recorded by ATLAS, with one W boson decaying to an electron and a neutrino, one W boson decaying to a muon and a neutrino, and a Z boson decaying to 2 muons; muons are proven by crimson traces, the electron by a inexperienced line, and ‘lacking vitality’ from the neutrino by a dashed white line. Picture credit score: ATLAS / CERN.
Because the carriers of the weak pressure, the W and Z bosons are central to the Normal Mannequin of particle physics.
Exact measurements of multi-boson manufacturing processes present a wonderful check of the Normal Mannequin and will make clear new physics phenomena.
“The manufacturing of three vector (V) bosons is a really uncommon course of on the LHC,” mentioned Dr. Fabio Cerutti, ATLAS physics coordinator.
“Its measurement gives info on the interactions amongst a number of bosons, that are linked to underlying symmetries of the Normal Mannequin.”
“This can be a highly effective software for uncovering new physics phenomena, reminiscent of new, undiscovered particles which can be too heavy to be immediately produced on the LHC.”
The ATLAS staff noticed VVZ manufacturing with a statistical significance of 6.4 customary deviations, surpassing the 5 customary deviation threshold wanted to say remark.
The remark extends earlier outcomes from the ATLAS and CMS collaborations, together with the remark of VVV manufacturing by CMS and the remark of WWW manufacturing by ATLAS.
As among the heaviest identified particles, the W and Z bosons can decay in a myriad of various methods.
Within the new examine, the ATLAS physicists targeted on seven decay channels with the very best discovery potential.
These channels have been additional refined utilizing a machine-learning approach referred to as boosted resolution bushes, with algorithms skilled for every channel to determine the sought-after sign.
By combining the decay channels, the researchers have been capable of observe VVZ manufacturing and set limits on contributions from new-physics phenomena to the sign.
“The ensuing limits verify the validity of the Normal Mannequin and are consistent with earlier outcomes on the manufacturing of three vector bosons,” they mentioned.
“As we analyze bigger information units from the LHC’s third run and the upcoming HL-LHC, we are going to additional refine our measurements of the manufacturing of three vector bosons — deepening our understanding of those elementary particles and their function within the Universe.”
The staff’s results will probably be revealed within the journal Physics Letters B.
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ATLAS Collaboration. 2025. Remark of VVZ manufacturing at s√=13 TeV with the ATLAS detector. Phys. Lett. B, in press; arXiv: 2412.15123
