October 5, 2022

Homing In on the Higgs Boson’s Interaction With the Charm Quark at the Large Hadron Collider

ATLAS and CMS have previously observed the interactions of the Higgs boson with the heaviest quarks and leptons, i.e. those of the third generation, which concur with the forecasts from the Standard Model within the existing measurement accuracy. They have also acquired the first indications that the Higgs boson interacts with a muon, a lepton of the second generation. Nevertheless, they have yet to observe it engaging with second-generation quarks. In two current publications, ATLAS and CMS report analyses that place tight limits on the strength of the Higgs bosons interaction with a charm quark, a second-generation quark.
Prospect occasions for a Higgs boson produced in association with a Z boson, as recorded by ATLAS (left) and CMS (best). The Higgs boson decays into a pair of jets (cones) stemming from appeal quarks, and the Z boson rots into muons (red lines on the left) or electrons (green lines on the right). Credit: CERN
ATLAS and CMS study the Higgs bosons interactions by looking at how it transforms, or “decays”, into lighter particles or how it is produced together with other particles. In their latest research studies, using information from the second run of the LHC, the two teams searched for the decay of the Higgs boson into an appeal quark and its antimatter counterpart, the charm antiquark.
To more quickly recognize this decay, ATLAS and CMS targeted their searches at Higgs bosons produced together with a z or a w boson rotting to electrons, muons (W, Z) or neutrinos (Z), and they utilized advanced machine-learning methods to identify jets stemming from beauty quarks. CMS also looked for high-momentum, or “increased”, Higgs bosons that result in 2 beauty jets collapsing into a wide jet.
The groups discovered no substantial indication of the decay of the Higgs boson into appeal quarks in the information, however their analyses set bounds on the rate at which this decay need to occur when the Higgs boson is produced along with a W and Z boson. These bounds represent ceilings on the interaction strength of the Higgs boson with a charm quark, of 8.5 and 5.5 times the Standard Model forecast in the case of ATLAS and CMS, respectively.
The ATLAS group went on to combine their analysis with a measurement of the Higgs boson decay into beauty quarks, demonstrating that the Higgs boson communicates more weakly with the appeal quark than it makes with the beauty quark. In other words, they found that the Higgs boson engages differently with quarks of the second and 3rd generations, as forecasted by the Standard Model.
Surprisingly, the CMS study permitted the CMS scientists to observe for the first time at a hadron collider the decay of the Z boson into appeal quarks, a perk observation that resulted from a recognition step in their look for the decay of the Higgs boson into appeal quarks.

In 2 recent publications, ATLAS and CMS report analyses that place tight limitations on the strength of the Higgs bosons interaction with a charm quark, a second-generation quark.
Candidate occasions for a Higgs boson produced in association with a Z boson, as recorded by ATLAS (left) and CMS (right). The Higgs boson decays into a pair of jets (cones) originating from charm quarks, and the Z boson decays into muons (red lines on the left) or electrons (green lines on the right). To more easily identify this decay, ATLAS and CMS targeted their searches at Higgs bosons produced together with a z or a w boson decomposing to electrons, muons (W, Z) or neutrinos (Z), and they used advanced machine-learning strategies to identify jets originating from appeal quarks.

New ATLAS and CMS analyses put tight limits on the strength of the Higgs bosons interaction with the appeal quark.
Considering that the discovery of the Higgs boson a decade back, the ATLAS and CMS collaborations at the Large Hadron Collider (LHC) have actually been hard at work attempting to open the tricks of this special particle. In particular, they have actually been examining in detail how the Higgs boson connects with fundamental particles such as those that make up matter, that is, quarks and leptons.

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