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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Should we protect artificial intelligence from sexual harassment?

Should anything be done to stop people sending sexually explicit messages to their AI personal assistants?

If you ask Apple’s artificially intelligent personal assistant “Siri” whether it is a virgin, it will waste no time in shooting you down. “We were talking about you, not me,” it replies in the clear, sharp tones of Susan Bennett, the woman chosen to voice the genderless computer program.

If you ask Apple’s artificially intelligent personal assistant “Siri” whether it is a virgin, you are probably not very weird. But a recent article in Quartz has detailed the extent to which AI systems – particularly personal assistant bots – are sexually harassed. Ilya Eckstein, CEO of Robin Labs, claims 5 percent of interactions in their database are sexually explicit, and that “some people try very hard to establish a relationship with the bot.”

Engineers have been aware of this problem for a while. Microsoft’s Cortana has been programmed to fend off sexual harassment, with Deborah Harrison, an editorial writer for the program, claiming: “If you say things that are particularly asshole-ish to Cortana, she will get mad.” But what about the other “female” AI out there? Amazon’s Alexa and Google Assistant, which is voiced by a woman, don’t currently seem to fend for themselves, so should we be fighting for them?

Probably not. Although developers should definitely program their “female” AI to shoot down anyone feeling frisky, as long as AI lacks sentience it’s hard to see these sexual interactions as a big enough problem to warrant further action. Yes, undoubtedly some lonely people have taken inspiration from Spike Jonze’s Her and fancy an AI girlfriend, and yes, a robust robot reply that teaches men to respect women can only be a good thing, but on the whole, most people that get saucy with Siri aren’t actually deranged perverts. They are just a boy, standing in front of a girl, asking them to say the world “willy”.

This is because despite what Quartz are claiming, the “sexual harassment” of bots is nothing new. It might, in fact, not even be gendered. Who among the MSN users of the Noughties didn’t ask the chatterbot SmarterChild whether he (most people, and media outlets, considered it a “he”) liked sex or had a penis? In fact, if you search Google Images for “Smarterchild”, pretty much all the screencapped chats are sexually explicit in some way.

Tumblr: The Dynamic Conversationalist

It’s hard to see someone sexting Siri as a problem, then, because it is part of a long tradition of humans being incredibly, incredibly dumb. Find me the man who doesn’t provoke every new chat bot on the market in the hopes of making them say something funny or rude, and you have found me a liar.

It is, of course, a big problem that AI personal assistants are so often female, as – in Laurie Penny’s words – it “says an uncomfortable amount about the way society understands both women and work.” But this, therefore, is the problem we should be tackling – instead of wasting our time debating the ethics and legality of coming on to Cortana.

I recently attended the UK launch of Amazon Echo, whose personal assistant is Alexa. Watching a room of old, balding, white, male journalists laugh heartily as the speaker on stage commanded Alexa to “Stop”, definitely troubled me. “If only I could get my…” began the speaker – as I desperately willed him not to say the word “wife” – “…children to do that,” he finished. Before we even begin to consider sexually explicit chatter, then, we should be confronting the underlying issue of gender bias in the AI industry.

Once we can set our personal assistants to have either male or female – or, even better, completely genderless – voices, we can get back to using them for what they were intended for. Asking them if they're virgins and then laughing at the response.

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