The ATLAS experiment, one of the four major experiments at CERN’s Large Hadron Collider in Switzerland, has reported the first evidence for the decay of the Higgs boson to a pair of bottom quarks.
The ATLAS Experiment presented evidence for a first sighting of the Higgs boson decaying to a pair of bottom quarks, with an observed significance of 3.6 sigma. Image credit: ATLAS Collaboration.
In 2012, CERN physicists reported the discovery of a new boson with a mass near 125 GeV and properties compatible with those expected for the Higgs boson — a fundamental particle first proposed in 1964.
In the Standard Model, the Higgs boson is a spin-zero particle predicted to arise from the Higgs field which is responsible for electroweak symmetry breaking.
To date, physicists have confirmed that the particle decays to three types of gauge bosons (the W and Z bosons, photons) and one type of fermions (tau-leptons).
However, these impressive achievements represent only 30% of the Higgs decays.
The Standard Model also predicts that the Higgs boson decays (58% of the time) to bottom quarks: H→bb.
“The strong evidence that the Higgs particle, as predicted by theory, decays into quarks provides yet another essential piece to the puzzle about this particle,” said ATLAS collaboration member Dr. Christian Weiser, from the Institute of Physics at the University of Freiburg, Germany.
Using data collected by the ATLAS detector at the Large Hadron Collider in 2015 and 2016, the physicists have found the first evidence for H→bb decay.
“This evidence for H→bb fills in one of the big missing pieces of our knowledge of the Higgs sector, suggesting that the Higgs mechanism is responsible for the masses of quarks,” they said.
“Further precise studies with higher precision are important to look for hints of new physics beyond our current theories.”
“This evidence of the decay of the Higgs boson to bottom quarks constitutes an important milestone in the exploration of the Higgs boson properties,” added ATLAS spokesperson Professor Karl Jakobs, also from the Institute of Physics at the University of Freiburg.
“It is important for the understanding of its short lifetime and for seeking indirect evidence for other, rarer decays.”
The researchers reported their results at the 2017 European Physical Society Conference on High Energy Physics in Venice, Italy.
_____
ATLAS Collaboration. Evidence for the H→bb¯ decay with the ATLAS detector. ATLAS-CONF-2017-041, 55 p.
