A candidate event display for the production of a Higgs boson decaying to two b-quarks (blue cones), in association with a W boson decaying to a muon (red) and a neutrino. The neutrino leaves the detector unseen, and is reconstructed through the missing transverse energy (dashed line). Credit: ATLAS Collaboration/CERN

Six years after its discovery, the Higgs boson has at last been observed decaying to fundamental particles known as bottom quarks. The finding, presented today at CERN by the ATLAS and CMS collaborations at the Large Hadron Collider (LHC), is consistent with the hypothesis that the all-pervading quantum field behind the Higgs boson also gives mass to the bottom quark. Both teams have submitted their results for publication today.

The Standard Model of particle physics predicts that about 60% of the time a Higgs boson will decay to a pair of bottom quarks, the second-heaviest of the six flavours of quarks. Testing this prediction is crucial because the result would either lend support to the Standard Model – which is built upon the idea that the Higgs field endows quarks and other fundamental particles with mass – or rock its foundations and point to new physics.

Spotting this common Higgs-boson decay channel is anything but easy, as the six-year period since the discovery of the boson has shown. The reason for the difficulty is that there are many other ways of producing bottom quarks in proton–proton collisions. This makes it hard to isolate the Higgs-boson decay signal from the background "noise" associated with such processes. By contrast, the less-common Higgs-boson decay channels that were observed at the time of discovery of the particle, such as the decay to a pair of photons, are much easier to extract from the background.

To extract the signal, the ATLAS and CMS collaborations each combined data from the first and second runs of the LHC, which involved collisions at energies of 7, 8 and 13 TeV. They then applied complex analysis methods to the data. The upshot, for both ATLAS and CMS, was the detection of the decay of the Higgs boson to a pair of bottom quarks with a significance that exceeds 5 standard deviations. Furthermore, both teams measured a rate for the decay that is consistent with the Standard Model prediction, within the current precision of the measurement.

Candidate event display for the production of a Higgs boson decaying to two b-quarks. A 2 b-tag, 2-jet, 2-electron event within the signal-like portion of the high pTV and high BDTVH output distribution is shown (Run 337215, Event 1906922941). Electrons are shown as blue tracks with a large energy deposit in the electromagnetic calorimeter, corresponding to light green bars. Two of them form an invariant mass of 93.6 GeV, compatible with a Z boson. The two central high-pT b-tagged jets are represented by light blue cones. They contain the green and yellow bars corresponding to the energy deposition in the electromagnetic and hadronic calorimeters respectively, and they have an invariant mass of 128.1 GeV. The value of pTV is 246.7 GeV, and BDTVH output value is 0.47. Credit: ATLAS Collaboration/CERN

"This observation is a milestone in the exploration of the Higgs boson. It shows that the ATLAS and CMS experiments have achieved deep understanding of their data and a control of backgrounds that surpasses expectations. ATLAS has now observed all couplings of the Higgs boson to the heavy quarks and leptons of the third generation as well as all major production modes," said Karl Jakobs, spokesperson of the ATLAS collaboration.

"Since the first single-experiment observation of the Higgs boson decay to tau-leptons one year ago, CMS, along with our colleagues in ATLAS, has observed the coupling of the Higgs boson to the heaviest fermions: the tau, the top quark, and now the bottom quark. The superb LHC performance and modern machine-learning techniques allowed us to achieve this result earlier than expected," said Joel Butler, spokesperson of the CMS collaboration.

With more data, the collaborations will improve the precision of these and other measurements and probe the decay of the Higgs boson into a pair of much-less-massive fermions called muons, always watching for deviations in the data that could point to physics beyond the Standard Model.

Candidate event display for the production of a Higgs boson decaying to two b-quarks. A 2-tag, 2-jet, 0-lepton event within the signal-like portion of the high pTV and high BDTVH output (Run 339500, Event 694513952) is shown. The ETMiss, shown as a white dashed line, has a magnitude of 479.1 GeV. The two central high-pT b-tagged jets are represented by light blue cones. They contain the green and yellow bars corresponding to the energy deposition in the electromagnetic and hadronic calorimeters respectively. The dijet invariant mass of 128.1 GeV. The BDTVH output value is 0.74. Credit: ATLAS Collaboration/CERN

"The experiments continue to home in on the Higgs particle, which is often considered a portal to new physics. These beautiful and early achievements also underscore our plans for upgrading the LHC to substantially increase the statistics. The analysis methods have now been shown to reach the precision required for exploration of the full physics landscape, including hopefully new physics that so far hides so subtly," said CERN Director for Research and Computing Eckhard Elsen.

Explore further New level of precision achieved in combined measurements of Higgs boson couplings

More information: Observation of Higgs boson decay to bottom quarks. arXiv:1808.08242 [hep-ex] Observation of Higgs boson decay to bottom quarks. arXiv:1808.08242 [hep-ex] arxiv.org/abs/1808.08242</s>Aug. 28 (UPI) -- Particle physicists have finally witnessed the decay of a Higgs boson particle into two bottom quarks.

Models predict Higgs boson particles decay into two bottom quarks 60 percent of the time. Bottom quarks, or b quarks, are the second heaviest of the six types of quarks.

Scientists have struggled to directly observe the predicted decay. Several types of proton-proton collisions can produce bottom quarks, making it difficult to link quarks produced by particle collisions with decaying Higgs boson particles.

Pairs of photons produced by decaying Higgs boson particles is much easier spot among the "noise" produced by high-energy particle collisions.

During experiments, scientists regularly witnessed the Higgs boson decaying into photons, tau-leptons, and W and Z bosons, but b quarks proved hard to see.

To isolate the link between decaying Higgs boson particles and pairs of bottom quarks, scientists combined the observations of the two particle detectors at CERN's Large Hadron Collider, ATLAS and CMS.

Physicists applied complex statistical analysis to the combined dataset. According to CERN, the analysis methods revealed "the decay of the Higgs boson to a pair of bottom quarks with a significance that exceeds 5 standard deviations."

"This observation is a milestone in the exploration of the Higgs boson," Karl Jakobs, spokesperson of the ATLAS collaboration, said in a news release. "It shows that the ATLAS and CMS experiments have achieved deep understanding of their data and a control of backgrounds that surpasses expectations."

Scientists working on the ATLAS experiment have now witnessed Higgs bosons decay into all of the heavy quarks and leptons predicted by particle physics models, including the Standard Model.

"Since the first single-experiment observation of the Higgs boson decay to tau-leptons one year ago, CMS, along with our colleagues in ATLAS, has observed the coupling of the Higgs boson to the heaviest fermions: the tau, the top quark, and now the bottom quark," said Joel Butler, spokesperson of the CMS collaboration. "The superb LHC performance and modern machine-learning techniques allowed us to achieve this result earlier than expected."

Researchers detailed their breakthrough in a scientific paper, published online this week. Scientists previously presented their findings at the 2018 International Conference on High Energy Physics in Seoul, South Korea.

Scientists hope their latest feat will pave the way for the detection of even more elusive decays, as well as the exploration of physics beyond the Standard Model.

"The analysis methods have now been shown to reach the precision required for exploration of the full physics landscape, including hopefully new physics that so far hides so subtly," said Eckhard Elsen, director of research and computing at CERN.</s>It’s been over half a decade since scientists working with the Large Hadron Collider (LHC) managed to capture what they believed was the elusive “God Particle” that would help tie together a few loose ends in our understanding of particle physics. It’s called the Higgs Boson and its discovery was a momentous occasion, but it also presented a few more questions that researchers desperately wanted to answer.

Now, with even more data from the Large Hadron Collider, a team of physicists has evidence to support previous theories about how the Higgs Boson behaves. That’s good news, because if the predictions didn’t pan out we might be looking for an entirely new model to explain how the most basic building blocks of our universe work.

Observing the behavior of a Higgs Boson is difficult because it decays rapidly. It turns into other particles in an instant, and figuring out what particles it turns into has been challenging ordeal for scientists. This new discovery revolves around what is called a “bottom quark.”

Existing models suggested that the Higgs Boson usually decays into the particles called bottom quarks. Bottom quarks have mass, and proving that the Higgs Boson decays turns into a pair of those particles was the focus of the research. Watching it happen would be impossible without the help of the extremely sensitive instruments in the LHC, but the researchers have now been able to isolate the feedback from that specific transition and demonstrate that the Higgs particle does indeed produce a pair of heavy bottom quarks more often than not.

“This observation is a milestone in the exploration of the Higgs boson,” Karl Jakobs, a member of the collaboration which conducted the research, explains. “It shows that the ATLAS and CMS experiments have achieved deep understanding of their data and a control of backgrounds that surpasses expectations. ATLAS has now observed all couplings of the Higgs boson to the heavy quarks and leptons of the third generation as well as all major production modes.”

In short, this is good news for physicists who work with what is known as the Standard Model of particle physics. If scientists hadn’t been able to observe the action, or if they saw something completely different in the resulting data, researchers would have to seriously consider a total revamp of one of the most basic physics models in use today. Thankfully, that’s not the case.</s>Six years after the strange, elusive Higgs boson particle was discovered, scientists working with the world's largest particle accelerator have finally observed its mysterious, yet most common, decaying process.

Using data from the Large Hadron Collider, physicists caught the boson decaying into two smaller particles - a bottom quark and its antimatter equivalent, an antibottom quark.

The Standard Model of particle physics predicts that a Higgs boson will decay into bottom quarks - the second-heaviest of the quark flavours - about 60 percent of the time.

Physicists have been trying to observe this process, because it will either support the Standard Model, or show that it's insufficient - requiring a search for new physics to explain the discrepancy.

The problem is that the process is extraordinarily hard to catch in action. The Higgs boson is produced by a collision between two protons. If two gluons inside the protons fuse and produce two top quarks, these top quarks can recombine into a Higgs boson.

This particle exists for about one-septillionth of a second before it decays into less massive particles. It's the detection of these particles from which particle physicists infer the existence of the Higgs boson.

There are several ways these particles decay, including into a fermion-antifermion pair, a pair of photons, or a pair of gauge bosons, which are relatively easy to observe.

But with bottom quarks, it gets a little trickier, because every proton-proton collision produces a shower of subatomic particles, including bottom quarks. These then rapidly decay into other particles.

Since the Higgs boson's existence is so brief, it's been impossible to determine whether the bottom quarks detected were the result of a decaying Higgs boson, or of proton collision background processes.

To find the decay, two collaborations - ATLAS and CMS - combined data from the first and second runs of the Large Hadron Collider, and analysed it to try and find bottom quarks from the particle showers they produced. Then they had to trace those bottom quarks back to a Higgs boson.

"Finding just one event that looks like two bottom quarks originating from a Higgs boson is not enough," said Chris Palmer, a physicist at Princeton University who worked on the CMS analysis.

"We needed to analyse hundred of thousands of events before we could illuminate this process, which is happening on top of a mountain of similar-looking background events."

However, there are a few particles that are identifiable by-products of the Higgs boson production mechanism.

"We used these particles to tag potential Higgs events and separate them out from everything else," Palmer explained. "So we really got a two-for-one deal with this analysis because not only did we find the Higgs decaying to bottom quarks, but we also learned a lot about its production mechanisms."

And they confirmed - again - the Standard Model of particle physics, with which the measured rate of decay matched.

It's a result that opens a new possibility for scientists to study the behaviour of the Higgs boson in closer detail, and how it interacts with other matter, plus whether it could interact with particles that haven't been discovered yet (such as dark matter).

The next step in the research is to refine the measurements to study the decay mode in much higher resolution.

Both collaborations have submitted their papers for publication in science journals, and in the meantime can be found on arXiv: the CMS research is available here, and the ATLAS research is available here.</s>PARIS-Six years after tracking down the Higgs boson, the subatomic particle that confers mass on matter, physicists said Tuesday they have “at long last” witnessed it decaying into tiny bits called “bottom quarks”.

The predicted decay was observed at the Large Hadron Collider (LHC) famous for the Nobel-capped discovery of the Higgs particle in 2012, Europe’s CERN physics lab announced.

“During the early preparations of the LHC, there were doubts on whether this observation could be achieved,” the ATLAS scientific collaboration said of the “elusive interaction” now documented at the massive particle accelerator.

Because Higgs bosons themselves are hard to find, and other particles also break up into bottom quarks, it has been difficult to track down those attributed specifically to Higgs decay.

Researchers say the long-awaited observation serves as further verification of the Standard Model of physics - the mainstream theory of the fundamental particles that make up the Universe and the forces that govern them.

Under the model, developed in the early 1970s, quarks and leptons are the most basic building blocks of matter.

There are six types of quarks, of which bottom quarks - also called beauty quarks - are among the heaviest.

The Standard Model predicted that Higgs decay would yield pairs of bottom quarks about 60 percent of the time.

But finding these quarks has been “among the most demanding analyses carried out by ATLAS so far,” the team said in a statement.

Scientists probing the nature and workings of the Higgs and other particles are on the lookout for anything that does not fit with Standard Model predictions.

This is because the model doesn’t explain dark matter or dark energy, and appears to be incompatible with the theory of gravity.

Some other model of “new physics” is needed to explain these.

Proposed alternatives have included the existence of extra dimensions, or “supersymmetry” which postulates the existence of a sibling of equal mass for every known Standard Model particle.

Evidence for neither has yet been found.

The latest observation was also “consistent with” the Standard Model, said the CMS team that worked with ATLAS on the project. But it “still leaves room for contributions from new physics.”

“It’s another point for the Standard Model,” physicist Pauline Gagnon told AFP.

While it was an important scientific breakthrough, the observation was also “a disappointment (for physicists) because the Standard Model has not yet been disproven.”

Physicists have sifted through mountains of experimental data these last years to piece together a profile of the elusive Higgs boson first predicted in 1964.

They have so far observed its mass, spin, and lifetime.

“In the coming years, much more data will be collected and the precision will be improved in our quest to see if the Higgs boson reveals the presence of physics beyond the Standard Model,” said the CMS collaboration.</s>Six years after the discovery of the Higgs boson, physicists have observed it decaying to fundamental particles known as bottom quarks. The discovery is a huge contribution to scientists’ understanding of the Standard Model of particle physics and the universe at large. The finding was presented on Tuesday at CERN1 by the ATLAS and CMS collaborations at the Large Hadron Collider (LHC). In 2012, physicists discovered the Higgs boson - an elementary particle predicted by the Standard Model which relates to how objects have mass.

The Standard Model of particle physics predicts that about 60 percent of the time a Higgs boson will decay to a pair of bottom quarks - the second-heaviest of the six flavours of quarks. The finding provides major support for the Standard Model, which has many implications for how we understand the world and the universe. Jessie Shelton, a high-energy particle physicist at the University of Illinois said: “The Higgs boson is the least well-known and in many ways the most baffling particle in the standard model. “Observing its decay to bottom quarts is a major milestone in our understanding of its properties.”

The discovery of the decay has been a long time coming, as there are many other ways of producing bottom quarks in proton-proton collisions. This makes it hard to isolate the Higgs boson decay from the background “noise” associated with such processes. The finding is another big step to better understand the Higgs boson and the universe. Each new discovery or observation, has the potential to give way to new questions and experiments.

James Beacham, an experimental high-energy particle physicist said: “First [you] discover the thing. Then you want to measure everything about it.” Karl Jakobs, spokesperson of the ATLAS collaboration, said the observation is a “major milestone in the exploration of the Higgs boson.” He said: “It shows that the ATLAS and CMS experiments have achieved deep understanding of their data and a control of backgrounds that surpasses expectations. “ATLAS how now observed all couplings of the Higgs boson to the heavy quarks and leptons of the third generation as well as all major production modes.”</s>I think that the quality of the content of the Quanta Magazine, a publication funded by a guru of mathematical physics and financier Jim Simons, seems to be dropping. Their latest text claiming to be about theoretical physics is titled



OK, once I saw the title and "James O’Brien for Quanta Magazine" near the top of the article, I was thinking: James, I've never heard of your name, but you seem to be a new clone of crackpot John Horgan who became notorious after he released his ludricrous book "End of Science" in 1996. No, dear readers, science hasn't ended and theoretical physics hasn't ended, either. They will only end when the human civilization does.To make the story short, I had to read the whole article before I was shown the actual author... Sabine Hossenfelder. James O'Brien just drew a childish picture that has nothing to do with any sufficiently well-defined concepts of science. OK, Sabine Hossenfelder is the actual author and that explains a lot. Surely an article in the Quanta Magazine must contain something a bit smarter than Horgan's idiotic rants about the end of science, mustn't it? Well, yes and no. The main claim made by Hossenfelder's short article is that in theoretical physics, brains are being replaced by computers, computer simulations, and "quantum simulations".Not really.Her text is full of ludicrous statements and a chaotic mixture of references to computing in science. It's completely unfocused and it is not clear what kind of (recent?) research she is talking about in most of her chosen examples.The first paragraph is dedicated to a different question – simplicity – and it makes a bold claim:Is theoretical physics complicated? Well, it depends how you define "complicated". The laws are simple in the sense that they're determined by some principles. They're much more beautiful and elegant than one would expect – beauty and elegance are among the first things that crackpot Hossenfelder loves to deny as well. But the laws of physics are not simple in the sense that everyone could understand them.In particular, Ms Sabine Hossenfelder hasn't understood the kind of laws that are used by state-of-the-art theoretical physics to describe Nature. She has never done a new, real, full-blown calculation in quantum field theory let alone string theory and she almost certainly doesn't have the intellectual potential to do the former, or to even learn the prerequisites needed for the latter. So her saying that theoretical physics is simple is no different from your dog's claims that Fermat's Last Theorem is trivial to prove. She is a clueless fraudulent fake researcher whom the most hopeless idiots in the general public (e.g. most of the self-described science journalists) consider a "go to physicist".Her claim about the simplicity makes it clear that she is one of the numerous female disciples of Lee Smolin's who famously told us at Harvard:In the corridors of Harvard, I've never heard something so laughable from someone invited as a theoretical physics which is why I will never forget about this authentic testimony about the Smolinisque kind of thinking – more precisely, the absence of thinking.The laws of Nature may be written as relatively compact expressions (although the full explicit form of the Lagrangian of the Standard Model still takes pages) but to understand what these symbols mean and how one should use them, at least in principle, one has to learn a pyramid of mutually dependent concepts that is arguably more intellectually demanding than any other scholarly discipline. The fact that the laws may be written exactly shows that theoretical physics is a hard science. It is hard, quantitative, and well-defined but these adjectives are something different than simple.In the bulk of the article, she randomly mentions numerical calculations, simulations of galaxy formations, and simulations of 2D superfluids – without saying anything substantial about any of them – and she tries to make the point that something is dramatically changing in the methodology of theoretical physicists that makes computers and simulations more central than the physicists' brains.The only problem is that this claim is just false. Simulations have been made since the first moment when computers were used. After all, the huge computers in the Manhattan Project were used to run a simulation (explosion of a nuclear bomb). That 1945 simulation was highly analogous to her galaxy and superfluid examples. So you can be sure that nothing qualitative has changed about these matters in the recent 70 years. And the analogies between superfluids and black holes – more generally between phenomena in different subdisciplines of physics – have been realized and exploited for centuries. A semi-recent class of such analogies exploded in the 1970s when Ken Wilson's "Renormalization Group" allowed us to study quantum field theory and classical statistical physics by the same toolkit.Are there some newer aspects of computing and simulations in physics? Well, yes. Just in a few recent decades, thanks to folks like Stephen Wolfram, we had good enough symbolic software that allowed us to compute results such as scattering amplitudes analytically. Certain folks in this "amplitudes" industry use computers to produce sometimes simple, often complicated exact formulae with many terms that take lots of pages to be reproduced.Now, computers are used – and have been used for decades – to analyze lots of data, e.g. those from the collisions at particle accelerators. That includes the reconstructions of tracks – recall that Edwin Steiner ended up very well in a Kaggle contest although he finally lost a medal (and the money). All of this software is getting better. A somewhat qualitative development was the expansion of machine learning in particle physics (and other disciplines).One shouldn't forget that the reconstruction of particle tracks and similar tasks really belongs to experimental physics, not theoretical physics.Some graduate students in theoretical physics are very good with computers, others are less so. That's true for postdocs and professors, too. However, theoretical physics hasn't switched to a system that would revolve about computers as the main "thinking gadgets". The main thinking gadgets are still the human brains. It's still true that the truly important papers and ideas are generated by human brains. They're a form of quantitative philosophy – note that Newton pioneered his physics under the slogan "mathematical principles of natural philosophy".And that's how theoretical physics primarily works today, too. The heart of the discipline still depends on a certain intellectual activity in which the human brains still show their superiority relatively to the computers.Lots of laymen I have met seem to be confused about this point (and their confusion is bound to increase whenever they read a deceitful article similar to Hossenfelder's rant). They are imagining that a theoretical physicist is someone who is playing with computers all the time – because he is interviewing the real guru of thinking, a computer. But that's simply not the case. A theoretical physicist primarily deals with the ideas – and invents new ideas – directly, using his or her brain. He or she is doing something analogous to a philosopher except that his brain and its products are or must be sharper, harder, and more quantitative than the philosophers' vague counterparts.Hossenfelder is also wrong about the separation of physics to "formulation of laws" and "solution of the laws". Well, the only thing she is correct about is the suggestion that one may divide the activity in this way. But among other things, she says that the formulation of laws is "trivial" and it's often hard to solve them. In reality, solving some equations or conditions is often hard but it may be and it should be considered straightforward and the problems are purely technical as long as the laws are really well-formulated. Well, we usually find aspects of solutions by clever thinking, not by brute force – which is one of the reasons why humans tend to beat computers even in the "solutions part" of theoretical physics. But in principle, well-defined laws can be solved by brute force.On the other hand, the finding of the viable laws themselves is not straightforward. It's the part of the process that really requires the exceptional human brains and this is why this part of the process must be considered harder. And she's also wrong that the important questions are really reduced to some complicated computations by computers. The most important questions are qualitative ones and even if they may be reduced to an aspect of a complicated solution, it's still more likely that a human brain finds the correct answer and its proof before a straightforward calculation is run to produce an answer.In real situations, computers tend to compute "details and precise values" of some problems whose rough behavior was first determined by a human brain. Even in factories, robots have embraced some jobs that were roughly done by human workers before. And at the end, we want some arguments comprehensible to human brains, anyway. Curious, critically thinking physicists wouldn't be quite satisfied if the answer to an important question were reduced to the faith in some unreadable run of a computer program. OK, the answer to everything is 42. But what have we really learned? Do we believe it? We might but we still prefer arguments comprehensible by the bare human brains.There are too many wrong things in her short article and it would take more space to address all of them. I am annoyed by the fact that the promising publication has been increasingly devoured by fake thinkers who are not thinkers at all and whose texts have no positive correlation to the scientific reality.Please, Dr Simons, stop this insanity. You are indirectly becoming a herdsman of self-serving clueless lying crackpots. And Cumrun and others who talk to Simons frequently enough, encourage him to regulate what's going on in that publication because without this supervision by the adults in the room, the publication starts to do a disservice, not service, to physics.</s>The ATLAS collaboration at the Large Hadron Collider has excitingly observed the Higgs boson decaying.

In a momentous event for physics, CERN physicists collaborating through ATLAS and CMS have finally, at long last, observed the Higgs boson particle decaying into bottom quarks, a new discovery which has been six years in the making after the exciting announcement of the Higgs boson in 2012.

According to ATLAS, the transition into two bottom quarks is estimated to account for around 60 percent of Higgs boson decays. ATLAS spokesperson Karl Jakobs announced the results of the ATLAS collaboration at the Large Hadron Collider today, noting that there were certainly doubts as to whether physicists would be able to catch the Higgs boson disintegrating.

“ATLAS is proud to announce the observation of this important and challenging Higgs boson decay. While the result is certainly a confirmation of the Standard Model, it is equally a triumph for our analysis teams. During the early preparations of the LHC, there were doubts on whether this observation could be achieved. Our success is thanks to the excellent performance of the LHC and the ATLAS detector, and the application of highly sophisticated analysis techniques to our large dataset.”

Physicists were curious to see whether the decay of the Higgs boson would follow the Standard Model of particle physics which gives the prediction that 60 percent of Higgs boson decays will see the Higgs particle continuing life as bottom quarks which, out of the six different flavors of quarks, just happens to be the second heaviest out of them all.

This made the new experiment all the more important as physicists would then know with the results whether the Standard Model, which provides quarks with mass, should be used or whether physicists needed to look at a completely new kind of physics.

Part of the reason why it has taken six years to spot the Higgs boson decay is because there are actually quite a few different ways in which to use proton-proton collisions to create bottom quarks. Because of this, it is quite difficult to “isolate the Higgs-boson decay signal from the background noise associated with such processes.”

However, Higgs boson decay channels that aren’t quite as common, like the process of photons decaying, are much simpler to differentiate from background noise, and it was determined that the decay of the Higgs boson was in keeping with the Standard Model prediction.

“To extract the signal, the ATLAS and CMS collaborations each combined data from the first and second runs of the LHC, which involved collisions at energies of 7, 8 and 13 TeV. They then applied complex analysis methods to the data. The upshot, for both ATLAS and CMS, was the detection of the decay of the Higgs boson to a pair of bottom quarks with a significance that exceeds 5 standard deviations.”

Now that CERN physicists at the Large Hadron Collider have successfully observed the Higgs boson decaying into a pair of bottom quarks, they will be gathering more data and continuing with their measurements of the Higgs into other decays, including its decay into muons.</s>Theoretical physics has a reputation for being complicated. I beg to differ. That we are able to write down natural laws in mathematical form at all means that the laws we deal with are simple — much simpler than those of other scientific disciplines.

Unfortunately, actually solving those equations is often not so simple. For example, we have a perfectly fine theory that describes the elementary particles called quarks and gluons, but no one can calculate how they come together to make a proton. The equations just can’t be solved by any known methods. Similarly, a merger of black holes or even the flow of a mountain stream can be described in deceptively simple terms, but it’s hideously difficult to say what’s going to happen in any particular case.

Of course, we are relentlessly pushing the limits, searching for new mathematical strategies. But in recent years much of the pushing has come not from more sophisticated math but from more computing power.

When the first math software became available in the 1980s, it didn’t do much more than save someone a search through enormous printed lists of solved integrals. But once physicists had computers at their fingertips, they realized they no longer had to solve the integrals in the first place, they could just plot the solution.

In the 1990s, many physicists opposed this “just plot it” approach. Many were not trained in computer analysis, and sometimes they couldn’t tell physical effects from coding artifacts. Maybe this is why I recall many seminars in which a result was degraded as “merely numerical.” But over the past two decades, this attitude has markedly shifted, not least thanks to a new generation of physicists for whom coding is a natural extension of their mathematical skill.

Accordingly, theoretical physics now has many subdisciplines dedicated to computer simulations of real-world systems, studies that would just not be possible any other way. Computer simulations are what we now use to study the formation of galaxies and supergalactic structures, to calculate the masses of particles that are composed of several quarks, to find out what goes on in the collision of large atomic nuclei, and to understand solar cycles, to name but a few areas of research that are mainly computer based.

The next step of this shift away from purely mathematical modeling is already on the way: Physicists now custom design laboratory systems that stand in for other systems which they want to better understand. They observe the simulated system in the lab to draw conclusions about, and make predictions for, the system it represents.

The best example may be the research area that goes by the name “quantum simulations.” These are systems composed of interacting, composite objects, like clouds of atoms. Physicists manipulate the interactions among these objects so the system resembles an interaction among more fundamental particles. For example, in circuit quantum electrodynamics, researchers use tiny superconducting circuits to simulate atoms, and then study how these artificial atoms interact with photons. Or in a lab in Munich, physicists use a superfluid of ultra-cold atoms to settle the debate over whether Higgs-like particles can exist in two dimensions of space (the answer is yes).

These simulations are not only useful to overcome mathematical hurdles in theories we already know. We can also use them to explore consequences of new theories that haven’t been studied before and whose relevance we don’t yet know.

This is particularly interesting when it comes to the quantum behavior of space and time itself — an area where we still don’t have a good theory. In a recent experiment, for example, Raymond Laflamme, a physicist at the Institute for Quantum Computing at the University of Waterloo in Ontario, Canada, and his group used a quantum simulation to study so-called spin networks, structures that, in some theories, constitute the fundamental fabric of space-time. And Gia Dvali, a physicist at the University of Munich, has proposed a way to simulate the information processing of black holes with ultracold atom gases.

A similar idea is being pursued in the field of analogue gravity, where physicists use fluids to mimic the behavior of particles in gravitational fields. Black hole space-times have attracted the bulk of attention, as with Jeff Steinhauer’s (still somewhat controversial) claim of having measured Hawking radiation in a black-hole analogue. But researchers have also studied the rapid expansion of the early universe, called “inflation,” with fluid analogues for gravity.

In addition, physicists have studied hypothetical fundamental particles by observing stand-ins called quasiparticles. These quasiparticles behave like fundamental particles, but they emerge from the collective movement of many other particles. Understanding their properties allows us to learn more about their behavior, and thereby might also to help us find ways of observing the real thing.

This line of research raises some big questions. First of all, if we can simulate what we now believe to be fundamental by using composite quasiparticles, then maybe what we currently think of as fundamental — space and time and the 25 particles that make up the Standard Model of particle physics — is made up of an underlying structure, too. Quantum simulations also make us wonder what it means to explain the behavior of a system to begin with. Does observing, measuring, and making a prediction by use of a simplified version of a system amount to an explanation?

But for me, the most interesting aspect of this development is that it ultimately changes how we do physics. With quantum simulations, the mathematical model is of secondary relevance. We currently use the math to identify a suitable system because the math tells us what properties we should look for. But that’s not, strictly speaking, necessary. Maybe, over the course of time, experimentalists will just learn which system maps to which other system, as they have learned which system maps to which math. Perhaps one day, rather than doing calculations, we will just use observations of simplified systems to make predictions.

At present, I am sure, most of my colleagues would be appalled by this future vision. But in my mind, building a simplified model of a system in the laboratory is conceptually not so different from what physicists have been doing for centuries: writing down simplified models of physical systems in the language of mathematics.</s>Today at CERN, the Large Hadron Collider collaborations ATLAS and CMS jointly announced the discovery of the Higgs boson transforming into bottom quarks as it decays. This is predicted to be the most common way for Higgs bosons to decay, yet was a difficult signal to isolate because background processes closely mimic the subtle signal. This new discovery is a big step forward in the quest to understand how the Higgs enables fundamental particles to acquire mass.

After several years of refining their techniques and gradually incorporating more data, both experiments finally saw evidence of the Higgs decaying to bottom quarks that exceeds the 5-sigma threshold of statistical significance typically required to claim a discovery. Both teams found their results were consistent with predictions based on the Standard Model.

“The Higgs boson is an integral component of our universe and theorized to give all fundamental particles their mass,” said Patty McBride, distinguished scientist at Fermi National Accelerator Laboratory and recently elected deputy spokesperson of the CMS experiment. “But we haven’t yet confirmed exactly how this field interacts—or even if it interacts—with all the particles we know about, or if it interacts with dark matter particles, which remain to be detected.”

Higgs bosons are only produced in roughly one out of a billion LHC collisions and live only a tiny fraction of a second before their energy is converted into a cascade of other particles. Because it’s impossible to see Higgs bosons directly, scientists use these secondary particle decay products to study the Higgs’ properties. Since its discovery in 2012, scientists have been able to identify only about thirty percent of all the predicted Higgs boson decays.

“We expected the Higgs would decay into bottom quarks most often, but it is crucial to see and measure it,” said Young-Kee Kim, the Louis Block Distinguished Service Professor in Physics and chair of the Department of Physics at the University of Chicago, who worked on the bottom quark decay of the Higgs with the ATLAS experiment in the past. “We now have seen all of the primary decay modes of the Higgs predicted by the current theory of particle physics, the Standard Model. This marks a very important moment in particle physics!”

According to Viviana Cavaliere, a physicist at DOE’s Brookhaven National Laboratory who works on the ATLAS experiment, finding the Higgs boson decaying into bottom quarks has been priority number one for the last several years because of its large decay rate.

“Theory predicts that sixty percent of Higgs bosons decay into bottom quarks,” said Cavaliere, who is also using this process to search for new physics. “Finding and understanding this channel is critical because it opens up the possibility for us to examine the behavior of the Higgs, such as whether it could interact with new, undiscovered particles.”

The Higgs field is theorized to interact with all massive particles in the Standard Model, the best theory scientists have to explain the behavior of subatomic particles.

“However, questions remain which cannot be answered by the Standard Model,” said Kim. “For example, is the Higgs responsible for giving mass to dark matter particles, the dominant form of matter in the universe?”

Kim's group is currently studying whether or not some fraction of Higgs bosons created in the LHC decay into dark matter particles.

Even though this decay is the most popular path, spotting it in the experimental data was no walk in the park. Every proton-proton collision at the LHC produces a splattering of subatomic byproducts, one of the most common being bottom quarks. These bottom quarks then quickly decay into other kinds of particles, leaving behind vast showers of particles in the detectors. Tracing these particle showers back to two bottom quarks (and then figuring out which ones came from a Higgs boson) is extremely delicate and labyrinthine work.

“Being able to identify and isolate bottom quarks in the experimental data is a huge challenge and required precise detector calibration and sophisticated tagging capabilities to identify b-quarks,” said Giacinto Piacquadio, a physicist at Stony Brook University who co-leads the Higgs-to-bottom-quarks analysis group. “We were only able to do these analyses thanks to years of work that came before.”
For the first time, scientists observe the Higgs Boson decay into bottom quarks. This supports a prediction in the Standard Model of particle physics.