After the Higgs hype, Cern still has as much purpose and passion as ever

As the tram trundles through the suburbs of Geneva, a huge lit-up globe by the side of the road lets me know I have arrived at Cern (the European Organisation for Nuclear Research). This is the mecca of particle physics. Most of it looks like a fairly undistinguished campus. "The money has not been spent on the buildings," I am repeatedly told. "The money is all underground." Underground, of course, are the tunnels where beams of light are smashed into each other. Under my feet are the colliders and detectors that are helping us understand what the universe is actually made of.

Above ground it's all fairly utilitarian. After dumping my bag in the spartan hotel, I head over to the big canteen. The streets are named things like Route Heisenberg or Route Democrite (Democritus postulated the first atom). Cern has four restaurants, but the big canteen is the centre of the place.

Cern, indeed physics itself, has entered popular consciousness in recent years. Geeks are pretty cool, and theoretical physics has replaced philosophy as a signifier of intellectual prowess. My 12-year-old had heard of the Large Hadron Collider. "That's where Sheldon wants to go." Indeed, a whole episode of The Big Bang Theory was about Leonard wanting to take his girlfriend to Switzerland to see the LHC, which resulted in Sheldon's paroxysms of jealousy. "But Penny has no interest in subatomic particle research! I've been dreaming of seeing the Large Hadron Collider since I was nine." I am no Sheldon, but have been wondering about Cern since seeing hordes of people cheering when the announcements about the Higgs boson (many people here call it the Goddam particle) were made and a recalcitrant Peter Higgs getting the Noble prize. "Oh yeah, sleeping bags everywhere, queues to get in," a young Canadian tells me. What do all these people do all day, I wondered, these people preoccupied by that which we cannot see?

As I sit down in the canteen – every expense spared, except for an Antony Gormley sculptural scribble hanging outside – it is obvious these people have their minds on something higher than decor. "Will I see anyone doing any physics?" I muse to myself without having any real idea what that might look like. Next to me two guys are talking Japanese but I can hear the words "configurations", "servers", "axes", "rubics". Just opposite, some young guys and an older man are actually working stuff out on the back of a napkin. This, I will soon realise, is how it is. Indeed, one of them tells me, "one of the top guys here works everything out on the back of an envelope. So he keeps a special supply of envelopes."

These people live and breathe physics. A young woman shows me the iPad she has just been "doodling" on. It's all numbers and equations.

Carl Sagan may have said that "we are all made of stars", but here this translates as "we are all made of numbers", and if you are not a numbers person, Cern is another planet. Often when I am talking to people, they will jump up and draw a quick graph to make their point, which only further confuses me.

It takes a while to get used to the international babble all around – "Cernish" is the common language – and the way people will introduce themselves: "I'm accelerators."

Cern, founded in 1954, has 20 member states, with many other countries co-operating. The atmosphere is collegiate but blokey. The ratio of men to women is about 80:20, but the women I meet are well supported. There is a creche and a kindergarten, and I see toddlers running round. The problem seems to be getting women into apprenticeships, and the UK as a whole suffers from our shortage of engineers. Once in, though, there appears to be less of an old boys' network than in many professions. "As long as you drink coffee, you are in."

Most people here – apart from the British – have four or five languages. Cern employs 2,000 people, but another 10,000 pass through, working on the four main experiments (AMS, CMS, Atlas and LHC).

This is a large and shifting community. People may come on student placements and then get work here. In summer the place is full of students drinking beer outside. To live here requires commitment – the surrounding villages either in France or Switzerland are expensive. But it soon becomes clear that people are here for the work, and the line between work and leisure is permeable. They often work 16 hours a day, because they want to. Even in the canteen.

"There is an etiquette. If they have their laptops open, it could be an ideas meeting," Claire Lee (physicist and Phd student) tells me. "Oh, they keep all hours," says Rachel Bray (product lifecycle management and document management specialist). "My office is next door to some theoretical physicists. I often see them rock up at 5.30. Or having a kip. There are no rigid hours."

Rachel tells me about all the clubs that Cern employees can go to. Many are keen to shake off the image of physicists as wild–haired, eccentric old men, and that image is easily disrupted when I see a hip young woman and a guy queueing for his dinner in the bottom half of a gorilla suit. "Physicists don't have the best dress sense," Rachel laughs. Indeed, it's all pretty casual. There are lots of clubs for those inclined and lots of winter sports, although some prefer to spend their spare time coding or doing robotics. Rachel asks me if I fancy some pilates at lunchtime, but I want to go and see the little office where Tim Berners-Lee invented the web. Cern has also given us cloud computing. It proves to be a hassle, however, to actually get online, and I have to get approval. "Cern is under constant attack from hackers."

When I ask most people what they miss, or what they have given up to be at Cern, they look bewildered. It seems a love of physics goes hand in hand with a love of skiing and snowboarding. They love the fact their children are in local schools and are bilingual.

Lucy Lockwood (HR systems analyst) has two small children, who her husband looks after, and says she doesn't have a social life, but she loves being "in this temple of physics". The problem I hear of over and over is that when a couple are both physicists or engineers, it can mean only one person gets the job they both want. Right across Cern there is movement between different roles: physicists become engineers. Everyone on an experiment will do overnight shifts in the control room. All this produces a less hierarchical way of working.

It is this flattening out of traditional structures that makes this place special, as well as the daily and huge international co-operation. Scientists whose countries are in conflict work together, Palestinians besides Israelis. Steve McMahon also explains: "Remuneration is not an issue. I may be working alongside eastern Europeans, for instance. We just don't talk about money".

The fact that the director is well paid, but not on a mega CEO/banker-type salary, helps this sense of common purpose. People are valued for their ideas and their ability to work across projects. "Hans Blix was here last week," someone will say casually. "Well, he would be. He is interested in Thorium." Or, "No one knew what to wear when the Dalai Lama came, so we wore Cern T shirts".

The philosophy of knowledge transfer and access to data adds to the openness of the place. The only real sense I get of hierarchy is when people talk in awe of Nobel prizewinners. If you get one of those, you can do what you like. Smoke cigars in your office. Jakob Steinberger, who won the Nobel in 1988 for his discovery of the muon neutrino, will be hanging out in canteen with every one else. "Its like a college. But with no undergraduates," says Alex Brown (development office). I soon stop asking people about their qualifications. "Only an obnoxious so-and-so would announce that they have a PhD. Best to assume whoever you are talking to does."

But if demarcations between nations and jobs dissolve under the mantra "We are all here for science", this is still a strange place to be, a transient society.

Alex explains the psychology: "You have to have a new model of friendship. You make friends, and in six months you have a whole new group and your best friend has gone." Instead this class of international young scientists uses Twitter, Facebook and Skype. Claire, who is wearing a bat on her headband for Halloween, is planning to paint herself blue for the evening's festivities. "You know, the Na'vi out of Avatar," she explains. If you want to bust the image of the average physicist, look no further. With funding from South Africa and Taiwan, she has a small baby whom her husband, an IT project manager, looks after.

Still, there is a Cern bubble that is hard to escape. Because Geneva has the UN, there is a large ex-pat community. Hugo Day (Marie Curie fellow) says he meets locals as he speaks the international language of heavy metal, and is honest about the limitations. "It is the place to be for physics. If you want cutting-edge, straight-up computer science, it would be IBM or Google." Now an engineer, after some years at Cern he is quite proud he doesn't ski. Ice climbing is his thing. And zombies.

Everyone I talk to bristles when I ask if, having found the Higgs, research has now stalled. The LHC is on "the long shutdown". The Higgs boson has actually thrown up more unknowns, from anti-matter and dark matter to supersymmetry and the inability of the standard model to incorporate gravity. All this work and these massive machines are about proving theories that are decades old. This is a long game. I go underground to see the CMS (Compact Muon Solenoid) particle detector, a massively complex but gorgeous piece of mega-engineering. We also see the AMS (Alpha Magnetic Spectrometer), and watching people sitting in a control room analysing data as it comes down from the international space station is fairly mind-blowing. A young Jordanian shows us round and tells us about Sesame, a major new research facility in the Middle East bringing in scientists from Egypt, Israel, Jordan, the Palestinian territories and Iran, among others. Its object is partly to promote peace through scientific co-operation.

Steve McMahon (Atlas upgrade tracker leader) commutes between Cern and the Rutherford Appleton lab in Oxfordshire, and like everyone here, is thankful for easyJet. He takes me round Atlas. He seems to know everyone, stopping to chat to an old Israeli, pipe-smoking professor. As he talks about everything from luminosity to his four children, to explaining the new dimensions and all the other bits of the universe to be explored (most of it) a Russian guy knocks on his door excitedly. He has had some good news on funding. "You know people say, 'It's not rocket science'?" says Steve. "Well, it is. He is a rocket scientist."

I tell him I like the big statue of Shiva in the grounds – the old "cosmic dancer" – but I sense a lot of people don't like big expressions of cultural difference, never mind faith. Everything is for a higher purpose, and that purpose is phsyics.

I have never been anywhere where I felt such a sense of shared purpose. It is in the canteen at lunchtime, where folk whizz about with trays of food and seemingly no system, as if they were crazed particles themselves, so that one fears a collision. But there is none – just this sense of charged intensity. People talk passionately in every tongue about the problems they are solving. Everywhere one feels these minds working collectively and intently, and even someone like me, who is not really up to speed on quarks, strangeness, mass and gluons, can pick up this terrific buzz.

What is the universe made of? Matter and force. Or, here, concentration and caffeine. And a new kind of excitement. Real energy. I begin to understand a little of what Lucy said earlier: "We are all here for what Cern is doing. This is a beautiful thing."

This article was amended on 8 November to correct the name of Leonard from The Big Bang Theory

The Guardian and Observer are media partners of the London Science Museum's Collider exhibition, which opens on Wednesday and runs until May 2014. More details: sciencemuseum.org.uk