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Can Higgs Boson Decay On Dark Things?

Concept of the Dark Sub-Atomic Particle Artist

Probably Dark Things Using Higgs Boson

Visible objects – everything from pollen to stars and galaxies – cost about 15% of the total mass of the Universe. The remaining 85% is made of something completely different from the things we can touch and see: dark things. Despite the overwhelming evidence from observing the effects of gravitational effects, the nature of the dark matter and its composition remain unknown.

How do physicists study dark matter beyond the effects of gravitational if it is not visible? Three different methods are pursued: indirect detection of astronomical observatories, searching for products decomposed by dark matter extinction in galactic centers; direct detection with highly sensitive experiments in low background, searching for dark matter scattered in nuclei; and by creating dark matter in the controlled environment of the Large Hadron Collider (LHC) laboratory in CERN.

Although successfully describing particle elements and their interactions at low energy, the Standard Model of particle physics does not include a viable dark particle. Possible candidates, neutrinos, do not have the right characteristics to explain the perceived dark matter. To solve this problem, a simple theoretical extension of the Standard Model implies that existing particles, such as the Higgs boss, act as a “portal” between known parties and dark objects. . Since the Higgs couple boson in the mass, enormous dark particles must come into contact with it. The Higgs boss still has major uncertainties associated with the strength of its interaction with Model Standard Adjectives; up to 30% of decomposing Higgs-bosons may be invisible, according to the latest ATLAS combined Higgs-boson measurements.

Maybe some of the Higgs bosses are rotting in the dark stuff? Because the dark matter does not directly interact with the ATLAS detector, physicists are looking for signs of “invisible particles”, which are rotated by preserving the momentum of proton-proton products. According to the Standard Model, the fraction of Higgs bosses that decompose in an invisible final state (four neutrinos!) Costs only 0.1% and is thus neglected. If such events should be followed, it is a direct indication of the new physics and potential evidence of Higgs bosses rotting in dark things.

Can Higgs boson decompose in dark matter? ATLAS Collaboration searched the entire LHC Run 2 scheduled to set the strongest limits on lowering the Higgs boson until dark objects disappeared until now.

At LHC, the most sensitive channel to search for direct decomposition of Higgs bosons into invisible particles is through the so-called vector boson fusion (VBF) producing Higgs boson. The VBF Higgs-boson results in two sprays of particles (called “jets”) that point in a more forward direction to the ATLAS detector. This, combined with a large missing momentum in the vertical direction (“opposite”) to the axis of the beam from invisible dark objects, creates a unique signature that ATLAS physicists can find.

Hypothetical Higgs Boson Signal Decaying to Invisible Final States

Figure 1: Mass of the top two jets (x-axis) in the search region with all background processes stacked and compared with the data. A hypothetical Higgs boson signal decaying in invisible final states is shown in red. Credit: ATLAS Collaboration / CERN

In the results presented recently, ATLAS Collaboration analyzed the entire LHC Run 2 listed, collected by the ATLAS detector in 2015–2018 to search for Higgs-boson decays in dark objects at VBF events. No significant excess events in the expected background from the well-known Standard Naming processes found in the review. ATLAS derives, with a 95% confidence level, an exception of Higgs-boson decay to invisible particles of 13%. This review includes almost 75% more data than previous ATLAS searches, and the team has implemented several improvements including:

  • Faster filtering algorithm to generate more simulated collisions and equivalent computing power. The lack of simulated events is the leading uncertainty in the first 13 versions of TeV of this review.
  • Optimized collision selection to accept ~ 50% more Higgs-boson events in the same dataset.
  • Fine event calculation to result in a higher signal-to-background ratio in search regions. This can be seen in Figure 1 as the red curve at the bottom panel increases with the higher invariant mass of the two leading jets (mjj).
  • Improved acceptance for resource collisions in background processes, allowing analysts to improve modeling in the background process.
Upper Limit in WIMP-Nucleon Cross Section

Figure 2: High limit on WIMP-nucleon cross-section with 90% confidence level obtained in this analysis compared to direct detection experiments. Credit: ATLAS Collaboration / CERN

The noticeable exception is consistent with no signs of Higgs boson decay in the dark matter. The new results promote the search for weak contact of massive particles (WIMPs), a popular candidate for dark matter. ATLAS sets additional exclusion limits for lower WIMP masses, which are compared to other direct detection experiments in Figure 2. These limitations are competitive with the best direct detection experiments for the mass of WIMP up to half the mass of Higgs-boson, assuming that Higgs directly contacts the boson in the dark matter.

This new analysis puts the strongest existing limits on lowering the Higgs boson until the particles are invisible. As the search continues, physicists will continue to increase sensitivity to the basic compression of dark matter.

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