The Large Hadron Collider, on the Franco-Swiss border near Geneva. Photo: Getty Images
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The Large Hadron Collider has made another exciting quantum discovery

Scientists working on one of the four experiments at the LHC have gathered enough evidence to confirm the existence of a four-quark particle.

Since the spectacular discovery of the Higgs boson in 2012, physicists at the Large Hadron Collider (LHC), the gigantic particle accelerator outside Geneva, have suffered a bit of a drought when it comes to finding new particles. In a welcome relief, the LHCb collaboration, who run one of four large experiments at the LHC, have announced one of the most genuinely exciting observations to come out of the 27km super-collider so far – an exotic particle that cannot be explained by current theories.

In the early 1930s physicists had a clean picture of the subatomic particles that make up our world. Every known atom has a tiny nucleus at its heart surrounded by a cloud of electrons, and each nucleus was made out of varying numbers of protons and neutrons. However, as the decades wore on a number of new, and somewhat unwelcome, particles were discovered, at first in detectors studying particles from outer space and later in particle-collider experiments.

By the 1950s, dozens of apparently elementary particles had been discovered, causing frustration among physicists who often brandish an inability to memorise a list of facts as a badge of honour. The famous physicist Enrico Fermi perhaps best expressed the mood of his colleagues in an infamous remark:

Young man, if I could remember the names of these particles, I would have been a botanist.”

Help came in the 1950s when physicists came up with a new model that explained most of these particles as being made up of a small number of truly elementary particles. Borrowing a line from James Joyce’s Finnegans Wake (a book that is even harder to understand than quantum field theory), Murray Gell-Mann dubbed these new particles “quarks”.

By the late 1960s the existence of quarks had been verified experimentally. We now know that there are six in total – the up, down, strange, charm, bottom and top quarks, along with six antiquarks (their anti-matter copies).

The quark model neatly explained all these peculiar particles. Protons, neutrons and many others besides are made of three quarks, belonging to a family known as baryons. Alternatively, a quark and an antiquark can pair up to form a meson.

Since then the quark model has been extremely successful, and is now a cornerstone of our understanding of particle physics. It was only at the turn of the millennium that some strange results started to suggest that the model might be incomplete. Until 2003 quarks had only been seen in twos or threes, but then a number of particles that looked like combinations of four quarks started to reveal themselves.

In 2008 the Belle Collaboration in Japan reported the observation of a new exotic particle – the unfortunately drably named Z(4430) (where for its negative charge). This has a mass that places it in a dense forest of charmonium states – particles that are made up of a charm quark and a charm antiquark. Crucially though, the Z is electrically charged whereas all charmonium states must be neutral, clearly marking it out as something unusual.

After a careful analysis of data from 25,000 decays of mesons resulting from more than 180 trillion collisions at the LHC in 2011 and 2012, the new announcement confirms the existence of Z(4430) with extremely high confidence. The particle was observed with an overwhelming significance of 13.9 sigma, well above the usual 5 sigma threshold required to declare a discovery. LHCb also went further than Belle by measuring the spin and parity of Z(4430), two quantum-mechanical properties that give a firm handle on the internal makeup of the particle.

The observation by LHCb is important because few physicists will take a result seriously until it has been seen by two independent experiments. This is why hundreds of millions of Euros were spent building two large detectors at the LHC. The observation of the Higgs boson by two independent teams, ATLAS and CMS, was what really convinced the scientific community that the particle was real.

This result is the clearest evidence yet of the existence of a tetraquark – a four-quark state, with the LHCb analysis suggesting that Z(4430) is most likely to be made of a charm, anti-charm, down and anti-up quark. Theorists are now able to add a whole new type of particle to the quark model and begin the hard work of trying to understand exactly how these four quarks are bound together.

Meanwhile, physicists working at the LHC experiments will continue to explore unmapped regions of the subatomic world, with the hope of turning up more members of this exotic new family. Now that we know that at least one is out there, it is very unlikely that Z(4430) is alone.The Conversation

Harry Cliff is affiliated with the University of Cambridge, CERN, the LHCb experiment.

This article was originally published on The Conversation. Read the original article.

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“Stinking Googles should be killed”: why 4chan is using a search engine as a racist slur

Users of the anonymous forum are targeting Google after the company introduced a programme for censoring abusive language.

Contains examples of racist language and memes.

“You were born a Google, and you are going to die a Google.”

Despite the lack of obscenity and profanity in this sentence, you have probably realised it was intended to be offensive. It is just one of hundreds of similar messages posted by the users of 4chan’s Pol board – an anonymous forum where people go to be politically incorrect. But they haven’t suddenly seen the error of their ways about using the n-word to demean their fellow human beings – instead they are trying to make the word “Google” itself become a racist slur.

In an undertaking known as “Operation Google”, some 4chan users are resisting Google’s latest artificial intelligence program, Conversation AI, by swapping smears for the names of Google products. Conversation AI aims to spot and flag offensive language online, with the eventual possibility that it could automatically delete abusive comments. The famously outspoken forum 4chan, and the similar website 8chan, didn’t like this, and began their campaign which sees them refer to “Jews” as “Skypes”, Muslims as “Skittles”, and black people as “Googles”.

If it weren’t for the utterly abhorrent racism – which includes users conflating Google’s chat tool “Hangouts” with pictures of lynched African-Americans – it would be a genius idea. The group aims to force Google to censor its own name, making its AI redundant. Yet some have acknowledged this might not ultimately work – as the AI will be able to use contextual clues to filter out when “Google” is used positively or pejoratively – and their ultimate aim is now simply to make “Google” a racist slur as revenge.


Posters from 4chan

“If you're posting anything on social media, just casually replace n****rs/blacks with googles. Act as if it's already a thing,” wrote one anonymous user. “Ignore the company, just focus on the word. Casually is the important word here – don't force it. In a month or two, Google will find themselves running a company which is effectively called ‘n****r’. And their entire brand is built on that name, so they can't just change it.”

There is no doubt that Conversation AI is questionable to anyone who values free speech. Although most people desire a nicer internet, it is hard to agree that this should be achieved by blocking out large swathes of people, and putting the power to do so in the hands of one company. Additionally, algorithms can’t yet accurately detect sarcasm and humour, so false-positives are highly likely when a bot tries to identify whether something is offensive. Indeed, Wired journalist Andy Greenberg tested Conversation AI out and discovered it gave “I shit you not” 98 out of 100 on its personal attack scale.

Yet these 4chan users have made it impossible to agree with their fight against Google by combining it with their racism. Google scores the word “moron” 99 out of 100 on its offensiveness scale. Had protestors decided to replace this – or possibly even more offensive words like “bitch” or “motherfucker” – with “Google”, pretty much everyone would be on board.

Some 4chan users are aware of this – and indeed it is important not to consider the site a unanimous entity. “You're just making yourselves look like idiots and ruining any legitimate effort to actually do this properly,” wrote one user, while some discussed their concerns that “normies” – ie. normal people – would never join in. Other 4chan users are against Operation Google as they see it as self-censorship, or simply just stupid.


Memes from 4chan

But anyone who disregards these efforts as the work of morons (or should that be Bings?) clearly does not understand the power of 4chan. The site brought down Microsoft’s AI Tay in a single day, brought the Unicode swastika (卐) to the top of Google’s trends list in 2008, hacked Sarah Palin’s email account, and leaked a large number of celebrity nudes in 2014. If the Ten Commandments were rewritten for the modern age and Moses took to Mount Sinai to wave two 16GB Tablets in the air, then the number one rule would be short and sweet: Thou shalt not mess with 4chan.

It is unclear yet how Google will respond to the attack, and whether this will ultimately affect the AI. Yet despite what ten years of Disney conditioning taught us as children, the world isn’t split into goodies and baddies. While 4chan’s methods are deplorable, their aim of questioning whether one company should have the power to censor the internet is not.

Google also hit headlines this week for its new “YouTube Heroes” program, a system that sees YouTube users rewarded with points when they flag offensive videos. It’s not hard to see how this kind of crowdsourced censorship is undesirable, particularly again as the chance for things to be incorrectly flagged is huge. A few weeks ago, popular YouTubers also hit back at censorship that saw them lose their advertising money from the site, leading #YouTubeIsOverParty to trend on Twitter. Perhaps ultimately, 4chan didn't need to go on a campaign to damage Google's name. It might already have been doing a good enough job of that itself.

Google has been contacted for comment.

Amelia Tait is a technology and digital culture writer at the New Statesman.