ATLAS Experiment adds more pieces to the Higgs boson puzzle

ATLAS Experiment adds more pieces to the Higgs boson puzzle
Cross sections time branching fraction for the main Higgs production modes at the LHC (ggF, VBF, VH and ttH+tH) in each relevant decay mode (γγ, WW, ZZ, ττ, bb). All values are normalized to Standard Model predictions. In addition, the combined results for each production cross-section are also shown, assuming the Standard Model values for the branching ratios into each decay mode. Credit: ATLAS Collaboration/CERN

The Higgs boson was discovered in 2012 by the ATLAS and CMS Experiments at CERN, but its coupling to other particles remains a puzzle.

Fortunately, the LHC provides many windows into measuring Higgs boson couplings. There are four main ways to produce the Higgs boson: through the fusion of two gluon particles (gluon-fusion, or ggF), through the fusion of weak vector bosons (VBF), or in association with a W or Z boson (VH), or one or more top quarks (ttH+tH). There are also five main channels in which Higgs bosons can decay: into pairs of photons, W or Z bosons, tau leptons or b quarks. Each of these processes brings unique insights into the Higgs boson properties.

Thanks to the unprecedented quantities of Higgs bosons produced at the LHC, all of the above production and decay modes have now been observed. In a new result presented by the ATLAS Collaboration, using data collected through 2017, the measurements for each of these processes have reached the significance threshold of five standard deviations, beyond which their existence is considered established.

The Higgs boson yields for most of the combinations of production and decay have been measured (see figure) and have been found to agree with Standard Model predictions. The measurement of the cross sections for each production mode in proton–proton collisions at 13 TeV, assuming the decays occur as predicted by the Standard Model, are the most precise ones obtained to date.

Physicists have also begun to explore the Higgs boson puzzle in a new way. In the latest analyses, instead of counting Higgs bosons inclusively in the major production and decay modes, ATLAS physicists have measured Higgs boson topologies separately for smaller regions of phase-space: different ranges of Higgs boson transverse momentum, numbers of associated jets, and numbers and kinematic properties of associated weak bosons and top quarks. Using these smaller puzzle pieces, called "simplified template cross sections" (STXS), allows physicists to better separate the measurement process from the interpretation in terms of theoretical properties. Ultimately, it provides a finer-grained picture of Higgs boson couplings at the LHC and more stringent tests of the Standard Model.

Among the STXS regions considered in the analysis, some have already been measured with good precision at the LHC, but no deviation from the Standard Model has been observed so far. These measurements allow physicists to further enhance the sensitivity on the coupling properties of the Higgs boson to the other elementary particles. Further, they have set constraints on new physics theories – such as the "two-Higgs doublet ", which introduces additional Higgs bosons, and the hMSSM supersymmetric model – which are more stringent than those reported previously by ATLAS.

These measurements will continue to improve as more data from Run 2 and beyond are included, providing a yet-finer picture of the properties of the Higgs .


Explore further

ATLAS experiment measures Higgs boson coupling to top quark in diphoton channel with full Run 2 dataset

More information: Combined measurements of Higgs boson production and decay using up to 80 fb−1 of proton—proton collision data at 13 TeV collected with the ATLAS experiment: atlas.web.cern.ch/Atlas/GROUPS … ATLAS-CONF-2019-005/
Provided by ATLAS Experiment
Citation: ATLAS Experiment adds more pieces to the Higgs boson puzzle (2019, May 7) retrieved 17 July 2019 from https://phys.org/news/2019-05-atlas-pieces-higgs-boson-puzzle.html
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May 07, 2019
"the LHC provides many windows into measuring Higgs boson couplings."

I often see complaints by antiDR/SR/QM woomingers that the LHC research is not instantly complete. That it is too complicated for them to comprehend.

That "Many Windows" phrase is an honest appraisal of what has been discovered,
& a forecast of how much still remains to be discovered.

To the antiscience cultists, they resent that science continues to correct * change & devekop & evolve,

The simpletons cannot keep up with new discoveries that leave the old pseudo-sciences obsolete. Redundant to needs!

The looneyticks & stuporstitious have nothing to contribute but disruption & obstruction of Humanities progress.

May 07, 2019
Ok here is my problem with all the findings using super colliders.... The presumption is said findings are equal to those found in interstellar space where the creation of energies, acceleration, gravitation, magnetism, and elements occur. But scientifically how can that be when no tests have been done in zero gravity or macro gravity (like a black hole or neutron star), in the cold vacuum of space while constantly being bathed in high and low energy galactic cosmic radiation? I am not saying the calculations are wrong, I am saying that the effects of earth's gravity and magnetic fields cannot be truly nullified. Thus all said findings are based on the effects on particles in a earthly environs and not in actual space....

May 07, 2019
@I pray now

Yes you are saying that everything that is done at the ungodly LHC is wrong, couching in the phrase, "I am not saying the calculations are wrong", doesn't undo your asshole logic.

May 07, 2019
"the LHC provides many windows into measuring Higgs boson couplings."

I often see complaints by antiDR/SR/QM woomingers that the LHC research is not instantly complete. That it is too complicated for them to comprehend.

That "Many Windows" phrase is an honest appraisal of what has been discovered,
& a forecast of how much still remains to be discovered.

To the antiscience cultists, they resent that science continues to correct * change & devekop & evolve,

The simpletons cannot keep up with new discoveries that leave the old pseudo-sciences obsolete. Redundant to needs!

The looneyticks & stuporstitious have nothing to contribute but disruption & obstruction of Humanities progress.

That should be - Humanity's... :-)
And it is the ATTEMPT to disrupt or obstruct that generates further progress... :-)

May 07, 2019
The models that are alternatives to the standard Higgs fields mechanism, the SU(2) doublet field [ https://www.forbe...fdb7330a ].

how can that be when no tests have been done in zero gravity or macro gravity (like a black hole or neutron star)


First let me rephrase to physics, you mean flat space - the average cosmological background - versus strong gravity fields - but note that the insides of black hole event horizons break physics, we don't know quantum particle fields exists inside. so are irrelevant here.

Second, you can see the power and beauty of perturbative Feynman diagrams here. They approximate *all* interactions between a quantum field and the environment vacuum, as long as we are outside black hole event horizons. And they are complete if the quantum field theory is, meaning that if physicists can predict Higgs they know all Standard Particle interactions.

- tbctd -

May 07, 2019
Why are we doing this nonsense?

May 07, 2019
- ctd -

https://en.wikipe..._diagram .

One - for some - unexpected discovery from a self contained "low" (less than TeV) energy model of everyday matter baryons is what physicists like Brian Cox, Neal deGrasse Tyseon and Sean Carroll pointed something out in public starting 2017. The emptying out of experimental checks was nearly complete at the time but the model worked. Meaning we could conclude remaining interactions - whether quantum field or not (but we know no other types, even gravity and simplest dark energy models conform outside black hole event horizons) - are too weak to inject mysteries and magic. We now know there are no 'miracles', no 'ghosts', no 'souls', no 'afterlife', and no 'rebirth'.

LHC did that for us, without needing to be subjected to strong fields as such. But collisions (high energies = strong fields) meant strong local fields I take it, and nitpicking: detectors and beam lines have very strong magnets outside the collision volumes.

May 07, 2019
Editing removed a reference link in my previous comment, and it was still poorly edited. New attempt at the first two sentences:

https://en.wikipe..._diagram , http://www.prepos...erstood/ .

One - for some - unexpected discovery from a self contained "low" (less than TeV) energy model of everyday matter baryons is what physicists like Brian Cox, Neal deGrasse Tyson and Sean Carroll pointed out in public starting 2017.

Why are we doing this nonsense?


You mean, like trolling something others cannot understand the meaning of, likely unrelated to the article under discussion!? Should you not ask yourself that?

May 07, 2019
I take it at this point that we are past the 'Higgs-like boson' stage, 2012. That we are past the 'walks-like-a-duck' stage. That all cross-fixes on the animal indicate the actual animal, 6 or 7-sigma...

May 07, 2019
ipray & hyped, I understand your infantile frustrations.

The scientists get to use all sorts of complicated technology to gather evidence to support their speculations towards explaining Reality.

All you guys got is some cheap jackinthebox, ouiijaboard, tin whistle & other rusty toys to sustain your superstitions & belief in pseudo-science mythology.

May 07, 2019
So, now we have the pattern and like always in science, we are filling in the blank spots in it. Looking for places where we say, "Gee, I wonder why it did that."

May 07, 2019
here is my problem with all the findings using super colliders.... The presumption is said findings are equal to those found in interstellar space ... zero gravity or macro gravity (like a black hole or neutron star) ... all said findings are based on the effects on particles in a earthly environs...

And the problem with your complaint is in replicating the LHC in either interstellar space or close to a black hole or neutron star, as you've suggested. I'd strongly encourage you to publish your proposal on how either could be achieved with current state-of-the-art technology.

May 08, 2019
I am tickled that people resort to insults instead of answering the question I posed about whether physicists would be able to replicate their findings in interstellar space (not the space between atoms or particles). And what I mean is building a super collider space station and launching it out of our solar system and conducting the exact same tests with the same controls and etc... without knowing the effects of zero gravity and radiation on hyper accelerated particles then saying you have a concrete answer is not science. This has nothing to do about religion. It has everything to do with true facts. And as a scientist who has done extensive research on Galactic Cosmic Radiation, I know there are several major gaps in our knowledge about the universe. To date no one knows what Dark energy or Dark matter is. No one has ever studied real black hole matter. Anyone of these could completely rewrite our understanding of our world both at the micro and macro environs....

May 08, 2019
Considering that we can see stars as far as we look and they all appear to behave the same as our Sun and all the nearby stars, I would say that your question is ill-thought and ill-formed. There's some subatomic physics for you. Explain how that can be if the physics there are different.

No hand-waving. And no FUD. Which is what you've been doing so far.

And I think @humy has you nailed, @PreysALot.

May 08, 2019
@ I pray alot

Anyone of these could completely rewrite our understanding of our world both at the micro and macro environs....

And you still would not accept the results.

May 08, 2019
I am tickled that people resort to insults instead of answering the question I posed about whether physicists would be able to replicate their findings in interstellar space (not the space between atoms or particles). ...
You got 4 downvotes on an innocuous enough objection, and my sympathies. And then:

And as a scientist who has done extensive research on Galactic Cosmic Radiation...
I don't think either of us are scientists. I took some physics in university, but honestly man... WUT

May 08, 2019
Oy! There were some serious cut-and-paste errors of mine yesterday.

"The models that are alternatives to the standard Higgs fields mechanism, the SU(2) doublet field [ https://www.forbe...fdb7330a ]."

The sentence that got missing was alluding to was something like that the "constraints on new physics theories – such as the "two-Higgs doublet model", which introduces additional Higgs bosons, and the hMSSM supersymmetric model" are the alternative models.

While the SU(2) doublet field is the simplest, standard model that is now shored up by tighter constrains against other theories. (Some of the figures of the resulting parameter space leaves just a small region around the standard Higgs.) I simply found it interesting and Siegel's illustration neat.

May 08, 2019
I am tickled that people resort to insults instead of answering the question I posed ... And as a scientist who has done extensive research on Galactic Cosmic Radiation, I know there are several major gaps in our knowledge about the universe. To date no one knows what Dark energy or Dark matter is. No one has ever studied real black hole matter. Anyone of these could completely rewrite our understanding of our world both at the micro and macro environs....


I would say that your inability to respond to my non-insult answer tell us that you are not interested in such. As for an anonymous 'scientist' that capitalize the subject area and gives no references, likely all will reject it for the time being - what is claimed without evidence can be rejected without evidence, and what is claimed with crackpot signature can be rejected as crackpottery signature.

- tbctd -

May 08, 2019
- ctd -

FWIW, the M87* black hole imagery strengthened the evidence for general relativity cosmology, so the evidence for dark matter and dark energy, as well as made the idea of black hole "matter" instead of a GR black hole (whatever it is) a whole lot weaker.

What we "know" about what DM and DE is can be argued, but the simple hypotheses (heavy non-EM particles respectively vacuum energy) are most supported by observing them. As the article, it is science in progress, certainly nothing to base suggestions of bad science or overturning science on.

May 08, 2019
Not follow the inventors of SUSY, WIMP, HIGGS, BIG BANG and so on - there is no new physics there ...

Here are the LHC results...:
https://drive.goo...xgaim-0j
Dr. Gunn
https://www.youtu...alv2f5oM


May 10, 2019
Is this science or is this a religion? I posed a serious question.... can the results of found in all the earth based super colliders be replicated in outer space in true zero gravity and constantly being bathed in galactic cosmic radiation? And as for the Higgs particle one anomaly that keeps happening is Twin Higgs particles popping up which was not predicted... if you can't answer my question scientifically then say so... personal attacks is beneath physics...

May 10, 2019
@I prey alot

You are insincere in your jackassery.

May 10, 2019
@hat1208 it's clear a bunch of wanna be's who couldn't tell the difference between an electron and proton troll this site... failure to answer a scientific question reveals your inability to fully grasp physics... to say the findings at the super c olliders are not affected by earth's gravity is plain stupid, and to think these experiments are the "be all end" is hubris to the max. I guessed I missed their discovering dark matter and dark matter and dark energy. Or capturing a wimp. Or how about simply bathing the hyper accelerated photons with high levels of ionized radiation and see if you get the same results when they collide. Then publish the results for all to see.

May 10, 2019
There are 6 category, One pair of them accurate regularity , decay into photon. common regularization of group. find out imply law would lead math&phy to edge of mirror.

May 10, 2019
@PreysALot, it's obvious that you don't have any scientific arguments and also can't answer real questions. Instead you concentrate on politics. You still haven't explained why if physics is different "out there," the stars mostly look like our Sun.

Like most cretinists and other losers, you whine about getting pwnt and ignore questions you have no answers for.

Coward.

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