ON HIS PHYSICS-INSIDER blog, Résonaances, theorist Adam Falkowski titled his latest post “After the Hangover.” He’s not talking about a party. He’s talking about particle physics—and the decline and fall of this year’s most-exciting-discovery-that-was-not.
On July 29, Falkowski declared what CERN, the European organization that runs the Large Hadron Collider, hasn’t yet: The Standard-Model-busting maybe-particle that has left physicists breathless since September actually isn’t busting anything. Because it’s not a particle. It’s just math, misbehaving. What appeared to be the signature of a brand-new thing was random fluctuations adding up in just the right way.
To make discoveries in particle physics, scientists have to accumulate lots of data. That data adds together, and tiny bumps that appear in the beginning can grow and gather significance. Or they can shrink. Particle physicists usually wait to declare a discovery until their results reach “five-sigma” confidence: If they did the same experiment 3.5 million times, they would see this result by chance just once.
But there’s a lot of lead-up to that five-sigma mark. And in that lead-up, physicists don’t just sit back in silence, wait, and wonder. They’re analyzing the data, theorizing about it. And gossiping about it—on Facebook, Twitter, blogs. Their murmurs usually make it into the wider world ahead of official announcements.
Within this physics rumor mill, the situation soon became clear: The LHC’s data was a fluke. But CERN wasn’t saying anything.
Falkowski thought people should know. So he decided to tell them ahead of schedule—“schedule” being a session and press event at the International Conference on High Energy Physics taking place in Chicago on Friday.
The Ghost Particle
Inside the Large Hadron Collider, physicists smash small particles together. These break apart, spreading subatomic debris and energy. Detectors catch the ultimate results of the collisions, and scientists work backwards to understand the particle chain that begat them. So far, physicists have only found particles predicted by the Standard Model, a framework developed in the 1970s. But this model has holes, and scientists are pretty sure it can’t be the whole story. They all cross their fingers that the LHC will discover something new, something that will confuse them and then lead them toward a more complicated understanding of the universe.
So they were thrilled when a December 15 presentation showed strange data from the LHC’s ATLAS and CMS detectors: an excess of photon pairs with energies of 750 gigaelectron-volts (GeV). They called it “the diphoton excess.” It wasn’t statistically significant, but it looked promising. It might have represented a particle six times more massive than the Higgs boson. Particle physicists got so psyched that they published 531 papers about it (isn’t that what you do when you’re psyched?). And they conversed.
“People talk,” says Falkowsi. They tweet. They send emails. Theorists are married to experimentalists, ergo particle-physics pillow talk. Falkowski says there is, in fact, a secret Facebook group that I am not allowed to join where physicists go precisely to discuss scientific rumors.
Falkowski watched his peers’ excitement, which mirrored his own. He published his own papers, and chronicled the saga on Résonaances, whose readership he estimates is 50 percent physicists. Previous posts on the same topic had the heds “Game of Thrones: 750 GeV edition” and “750 ways to leave your lover.”
The insider chatter started to become bleak, though, not long after the LHC started taking its first 2016 data in April. Different people brought different pieces of information to the secret group, and none of it looked good: The bump was disappearing. CERN stayed silent.
It’s been clear since June 20, Falkowski says, that the end was nigh. “And there’s a huge community out there, and they’re waiting for this result,” he says. On June 21, he tweeted:
There were people around the world reading papers, writing papers, imagining the universe as it might be and what it would mean if it were. But Falkowski knew that these scientists were essentially writing anatomy articles about a jackalope.
“The fact that the experiment waits so long to announce this result, it doesn’t make any sense,” he says. “There is no really good reason for that.”
So on July 29, he pressed publish on a kind of obituary for the diphoton excess, making its death more than mere gossip. “We are currently going through the 5 stages of grief,” he wrote.
In the Beginning
Falkowski began Résonaances in 2007 when he was a postdoctoral researcher at CERN. He knew about the “blogosphere,” about sites like Sabine Hossenfelder’s Backreaction. “‘Why can’t I do it?’” he says he thought. “‘I’m at the center of the universe at CERN, so I could write something about what’s going on there.’”
It was winter, he thinks probably a rainy day, when he actually did it. “I had nothing else to do, so I just started writing,” he says. At the time, he was anonymous: Jester. Few people paid attention. But then his clicks started to creep up. “It was just a small thing for fun,” he says, “but it evolved into something more far-reaching than expected.”
Not quite far-reaching on the pop-level. His readers are serious about science’s specifics, whether they’re working physicists, former researchers, or autodidacts. He says he learns something new from 10 percent of the comments that come in.
I first came across his blog in 2014, when Falkowski wrote about flaws in an analysis of primordial gravitational waves. The BICEP2 team had just had a big-fanfare press conference on March 17, 2014, to announce their result—evidence of cosmic inflation, gravitational waves from the beginning of the universe. The words “Nobel Prize” were thrown around.
Falkowski wasn’t buying it.
He talked to lots of people who were in the field—outside his own area of expertise—to get a handle on their reservations and form his own. “I had to weigh the evidence and what I heard from people who were explaining what went wrong,” he says. Two months after the big press announcement, on May 12, he hit publish. Nature picked up on it.
Nine months later, in February 2015, the BICEP2 team made the statement themselves: Their analysis was flawed. “They had to bite the bullet,” Falkowski says. “They did this. They made the mistake. …They probably were unhappy with the way it was announced. But I never received any complaint from them about this story.”
Particle No More
By the time Falkowski was convinced the LHC’s diphoton bump was a ghost, lots of the physics community knew too. But others hadn’t yet heard, and without word from the inside, they couldn’t be sure. Falkowski doesn’t like the I-know-and-you-don’t of institutional holdback. “I think there is always a value in sharing information and in openness,” he says.
“People invest a lot of time and resources and energy into this,” he continues. “And I think if there is something obviously wrong, they should know.”
There are, of course, reasons that scientific organizations want to control the dissemination of information. It’s an attempt to ensure that the right information gets out, not just rumors; to stop premature data from leading people to incorrect conclusions. It’s also probably to get glory. But information will make itself free, one way or another, before press conferences. And sometimes the most well-planned announcements are the ones disseminating incorrect, or at least premature, conclusions.
For the most part, even though physicists knew of the disappearance of the diphotons early—and, a little later, so did people stalking around Twitter and science gossip blogs—people for the most part weren’t saying anything. Thursday afternoon, a day early, an abstract appeared on the CERN document server about the data surrounding goneness of the non-particle. While it initially contained the words “no significant excess,” the CMS collaboration removed those words. It seems CERN, the institution, isn’t so good at keeping its own secrets. Twitter noticed, but many journalists who had surely pre-written their articles still didn’t really call it until the official word came, at 10 am Eastern time today. We are all of us playing a weird game of chicken.
Even though this potential discovery didn’t pan out, Falkowski doesn’t think the time physicists spent on it was a waste. “I can perfectly imagine how this looks from the outside,” he says. “You have this rush of theorists who are writing 500 papers about nothing, something that disappears,” he says. “And there are some questions they have to ask themselves. But at the end of the day, one has to stress that no animal was hurt.”
Physicists saw something they couldn’t explain. They tried to explain it. And while the specifics of those explanations won’t make it into text- or history books, it’s likely every scientist who participated in the jackalope chase learned something. And the other option—putting data out of mind until there’s confirmation—would just slow down science. If the particle were actually a particle, physicists would have a pretty epic running start right now.
Still, Falkowski—and probably every particle physicist—is disappointed. He wanted to move beyond the Standard Model, and this seemed to be the shot. “But,” he clarifies, “the reason why I’m depressed is not because this particular bump went away but because it’s not clear we’ll get another chance. We badly need a discovery in our field to keep it moving. We’ve been waiting for so long, and it’s not coming.”
You can be sure, though, that if another chance does come, Falkowski will let you know.