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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The mother lode: how mums became the ultimate viral fodder

The internet’s favourite joke used to be "your mum". Now it's "my mum".

“I was like: oh my.”

Terri Squires is describing her reaction to the news that she had gone viral. Last month, more than 213,000 people shared a tweet about Terri – but it wasn’t sent from her account. The 50-year-old Ohioan was propelled to internet stardom by her son, Jeff, who had tweeted about his mother.

“I didn’t really realise what it meant at first until he was like: ‘Mum, you do realise that millions of people have looked at this?’ … When I started seeing those numbers I was like: ‘Oh boy’.”

It’s a funny story – and Terri laughs heartily all she tells it. After coming out of a meeting, she checked her phone and noticed a picture of a missing – white – dog on Facebook. She quickly texted 17-year-old Jeff to check that the family dog, Duey, was safe. “That’s not Duey… Duey’s face is brown,” replied her son. “OK – just checking,” replied Terri.

More than 600,000 people “liked” Terri’s mistake after Jeff shared screenshots of the text message exchange on Twitter. But Terri is just one of hundreds of mums who have gone viral via their sons and daughters. Texts mums send, mistakes they make, things they fail to notice – these have all become the ultimate viral fodder.

In the last three months alone, Gerald’s mum went viral for a microphone mishap, Adam’s mum shot to Twitter fame for failing to understand WhatsApp, Lois’ mum got tricked by her daughter, Harry’s mum was hit in the head with a football, Hanna’s mum misunderstood a hairstyle, and Jake’s mum failed to notice her son had swapped a photo in her home for a portrait of Kim Jong-un.

But how do the mothers behind these viral tweets feel?

“I'm pretty much a mum that everybody wants to talk to these days,” says Terri, with another warm laugh. The mum of three says going viral “is not that big of a deal” to her, but she is happy that her son can enjoy being a “local superstar”. But is she embarrassed at being the punchline of Jeff’s joke?

“Believe me, I have thick skin,” she says. “I kinda look at what it is, and it’s actually him and his fame. I’m just the mum behind it, the butt of the joke, but I don't mind.”

Not all mums feel the same. A handful of similar viral tweets have since been deleted, indicating the mothers featured in them weren’t best pleased. A few people I reach out to haven’t actually told their mums that they’re the subject of viral tweets, and other mums simply don’t want any more attention.

“I think I’ve put my mum through enough with that tweet already,” says Jacko, when I ask if his mum would be willing to be interviewed. In 2014, Jacko tweeted out a picture of his family writing the word “cock” in the air with sparklers. “This is still my favourite ever family photo,” he captioned the tweet, “My mum did the ‘O’. We told her we were going to write ‘Love’.”

“No one ever expects to call home and say ‘Mum, have you heard of something called LADbible? No, you shouldn’t have, it’s just that a quarter of a million of its fans have just liked a photo of you writing the word ‘cock’ with a sparkler’,” Jacko explains.

Although Jacko feels his mum’s been through enough with the tweet, he does say she was “ace” about her new found fame. “She’s probably cooler about it all than I am”. Apart from the odd deletion, then, it seems most mums are happy to become viral Twitter stars.

Yet why are mums so mocked and maligned in this way? Although dads are often the subject of viral tweets, this is usually because of jokes the dads themselves make (here’s the most notable example from this week). Mums, on the other hand, tend to be mocked for doing something “wrong” (though there are obviously a few examples of them going viral for their clever and cunning). On the whole: dads make jokes, mums are the butt of them.

“We all think our mums are so clueless, you know. They don’t know what’s going on. And the fun thing is, one day we come to realise that they knew way more of what was going on than we thought,” says Patricia Wood, a 56-year-old mum from Texas. “People always kind of make fun of their mums, but love them.”

Last year, Patricia went viral when her daughter Christina tweeted out screenshots of her mum’s Facebook posts. In them, Patricia had forgotten the names of Christina’s friends and had candidly written Facebook captions like: “My gorgeous daughter and her date for formal, sorry I forgot his name”. Christina captioned her tweet “I really can't with my mom” and went on to get more than 1,000 likes.

“I felt, like, wow, it was like we’re famous, you know. I thought it was really cool,” says Patricia, of going viral. Her experiences have been largely positive, and as a part-time Uber driver she enjoys telling her customers about the tweet. “But I did have one bad experience,” she explains. A drunken passenger in her car saw the tweet and called Patricia an “asshole”.

Another aspect of viral fame also worried Patricia. She and her daughter were invited on a reality show, TD Jakes, with the production company offering to pay for flights and hotels for the pair. “I have too many skeletons in my closet and I didn't want them to come dancing out,” says Patricia, of her decision not to go. “By the time I got off it, it would be the Jerry Springer show, you know. I’m kind of a strange bird.”

On the whole, then, mothers are often amused by going viral via their offspring – and perhaps this is the real beauty of tweeting about our mums. Since the moment they earn the title, mums can’t afford to be fragile. There is a joy and relatability in “my mum” tweets – because really, the mum in question could be anyone’s. Still, from now on, mums might be more careful about what they tell their sons and daughters.

“When I send Jeff a text now I make sure I’m like: ‘Is my spelling correct? Is what I’m saying grammatically correct?’,” says Terri, “Because who knows where the words are gonna end up?”

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