Higgs boson turns ten: the mysteries physicists are still trying to solve

Host: Benjamin Thompson

Welcome back to the Nature Podcast. This week: the Higgs boson turns ten.

Host: Nick Petrić Howe

And how to support scientists who stutter. I’m Nick Petrić Howe.

Host: Benjamin Thompson

And I’m Benjamin Thompson.

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Host: Benjamin Thompson

This week marks a momentous milestone for physics. Ten years ago this week, scientists at CERN in Switzerland announced that they’d found evidence of the existence of the Higgs boson – a fundamental particle first theorised to exist nearly 60 years earlier. Discovered by researchers smashing particles together in the Large Hadron Collider (LHC), the Higgs boson is a key part of the standard model – physicists’ best description of the elementary subatomic particles, and the fundamental forces between them, that make up the Universe. To celebrate the particle’s tenth birthday party, we got two people together who know an awful lot about particle physics – Lizzie Gibney, a senior reporter for Nature, and Federico Levi a senior physics editor for the Nature journal. We sat them down to reminisce about what the discovery meant at the time, and what questions are left to be answered about this mysterious particle.

Lizzie Gibney

Fede, can you remember where you were, what you were doing when the Higgs was discovered?

Federico Levi

I definitely do. Yeah, I was still doing my PhD, actually. We crowded the main room of the physics department to look at broadcast in real time because people knew that something was in the air. And we were all there and it was amazing.

Lizzie Gibney

I heard people camped outside the lecture theatre at CERN, like from the night before, to be able to actually fit into that room.

Federico Levi

That must have been incredibly exciting to be there on site. I wasn't in Geneva, but the buzz was palpable. And everybody was texting one another going like, ‘This is incredible.’ So, it was quite a momentous moment.

Lizzie Gibney

Yeah, I was a reporter at the time, but not here at Nature, and I was writing for a publication that was more about policy rather than like research itself. But I remember, I was actually at a scientific event at the Royal Society in London, and there was so much buzz that evening. And because I had actually worked previously at CERN as a kind of staff writer as an intern, I had lots of questions from my friends and family, so they were being pinged at me all the time. It was great. It was kind of the first moment really that particle physics felt like it had broken through in that way. It was a subject for people on the street to talk about. But I do remember as well that, when they made the announcement, I just said now that it was a discovery, but they were quite cautious at first, weren’t they? They said we found a Higgs-like particle or something like that. They didn't say, ‘We've definitely got the Higgs boson.’ Why were they so cautious?

Federico Levi

As you know well, physicists tend to be quite cautious, right. And I think that deep inside their hearts, many people felt differently than what they actually said. But the evidence that was presented on that day was the presence of a particle with a certain mass. And it was a particle that was definitely off the chart. It was not corresponding to any particles that we knew already.

Lizzie Gibney

It was new.

Federico Levi

It was a new particle, exactly, with a mass that was exactly in the range that people expected the Higgs boson to be. And so, people were like, ‘That seems to be the thing we're looking for but clearly there is so much more to characterise about this,’ and definitely people have been busy since.

Lizzie Gibney

Yeah, so maybe we should tackle a bit of what it actually is because we've heard about how grand a discovery it was, but why was it so important to find the Higgs?

Federico Levi

Well, first of all, I wasn't around back when other particles conjectured by the standard model had been detected, and I could imagine that the excitement was similar. But in a way, the Higgs is so fundamental that it has almost a different status. It was sort of like something that had to be there for everything else that we've seen to make sense. It was really sort of the keystone that holds together a big mathematical construction – that is the theory of the standard model. And so, it's amazing that that particular thing, which comes from a very sort of human idea, which is the maths behind it, actually exists. To me, it’s mind blowing, right, and I think that many people felt that way.

Lizzie Gibney

I mean, people might have heard of a boson being something like a photon, but photons don't have mass, and that's the electromagnetic force. And then we've got the weak nuclear force, which has bosons, which do have a mass – they’re the W and Z bosons. And so, if I'm right, this is what the Higgs mechanism was doing, was giving some maths that would explain those two phenomena and how they could both equally fit in the standard model.

Federico Levi

Yeah, that's exactly it. Basically, how these two different forces could be different representations of a bigger structure, despite them being so different from a physical perspective.

Lizzie Gibney

And for that we need the Higgs field, which is this idea that Peter Higgs, but also a whole alphabet of other physicists, helped to discover and to theorise. So, this field exists that gives other particles mass, and the boson then, how does that relate? The boson isn't what's giving the mass, right? It's the field.

Federico Levi

The boson is the excitation of the field. So, in a way, if the field is there, the way you see it is through the corresponding boson. So, the Higgs boson is what you can use to actually sort of probe the field, which is, as you said, the fundamental entity that gives then masses to the rest.

Lizzie Gibney

And the way then that it works is that the more a particle interacts with the field, the more mass it has. Is that the general idea? So, when you have a really heavy particle, it's because it's reacting in a strong way with the field.

Federico Levi

Yeah, that's exactly it. I think that, like a mathematical perspective, what we call mass is effectively a drag that the particle feels through the Higgs field.

Lizzie Gibney

That's cool thing to mess with your brain, isn't it? So, as you said, Peter Higgs came up with this idea 50-60 years ago, a long time ago. And in terms of what we’ve learnt so far, I mean, the main thing is just how well it does fit with the standard model.

Federico Levi

It is fitting perfectly. And I think that that's, yet again, a moment that you almost want to pause and consider how incredible it is that something that was theorised 60 years ago, it's exactly been revealed in experiments. So, our description of reality is perfectly matching what nature is throwing at us. Nobody said that this should happen.

Lizzie Gibney

And so, we're ten years in. What did it mean for you in terms of papers and publishing? And how did it change physics in that way?

Federico Levi

It's an interesting question because, at some level, there is something about these huge discoveries that seem to change everything, but they don't really change that much in the end because, if you browse particle physics journals or articles, you will see articles that are very similar to the articles that used to be around, just with the Higgs in it, right. And that's actually, it's so deep, the difference, and yet so almost unnoticeable because, basically, most of the research these years has been focused on understanding the Higgs’ interaction with particles. And so, several results are how can we measure this better? What have we measured so far? Here's an idea on how to increase the precision on measuring this interaction with that. Essentially, particle physics got down to it and like they really kind of get going applying the expertise accumulated over decades of work with other particles to the Higgs.

Lizzie Gibney

So, the discovery was kind of like a starting gun and then you're like, ‘Oh, actually, we have to pin down all its properties and all the Higgs’ interactions and figure out how all those results then fit with theory.’ But I assume there are still a lot more questions that physicists want answered.

Federico Levi

Absolutely. To start with, given that the Higgs interacts more with heavier particles, we have seen only the interaction with the heaviest particles, whereas the interaction between the Higgs boson and the lighter particles, such as the ones that actually make up the world, such as electrons, protons and neutrons, it is much harder to realise this experimentally. And so, this has not been really observed yet with enough statistics to make any estimates. So, that's definitely something that the community would like to explore next. And this is clearly an effort to, first of all, check whether the standard model, as annoyingly accurate as it's been so far, keeps being so annoyingly accurate, if you want. But also, the Higgs boson is one of the many possibilities that could be happening to explain what we've seen. So, there are a number of conjectures that, if you want to set the stage for beyond the standard model physics, that involve the Higgs boson in some way. There could be more Higgs bosons or some conjectures are whether the Higgs boson is a composite particle, so whether it's made of something else.

Lizzie Gibney

So, it's not fundamental.

Federico Levi

We have no idea. There are basically theories for everything you can imagine, right? But then the experimental evidence needs to be accrued. So, there is so much that we need to understand.

Lizzie Gibney

And so, how big a deal is the discovery of the Higgs? if we look at, like the history of physics, of science, how far up there is it? Of course, it's part of the standard model. There have been lots of different inputs to the standard model over the years, but it is also that last missing piece that was discovered.

Federico Levi

Well, I was hoping you wouldn't ask me this question, but here I am.

Lizzie Gibney

Maybe personally because that’s the other thing is for you in your life, it probably has been a bigger deal than the discovery of relativity was because you weren't around.

Federico Levi

That is fair. That is accurate. No, I think it's basically up there to be honest because, to an extent, this is the equivalent of one of those first, early experiments that actually confirmed the theory of relativity. Because at some level, the standard model, the paper by Peter Higgs and all the other researchers of that time, remain quite bound to the realm of physics literature, until an experiment, bang on, realises that these people were right. And this is something so fundamental about the workings of nature, similar to relativity in a way, that is really like, ‘Okay, this is how the world works.’ So, these moments come very rarely in human history, so I would say that it's definitely up there. Don't ask me to put it before or after relativity, but I would say it's up there.

Lizzie Gibney

We were quite lucky to be around to see it.

Federico Levi

Absolutely, absolutely. Well, let's hope there is something else coming.

Lizzie Gibney

That's true. This might not be the end of the story.

Host: Benjamin Thompson

Lizzie Gibney and Federico Levi there, discussing the Higgs’ tenth anniversary. This is an edited down version of their chat, and there was so much fascinating stuff that we didn’t have time to include in this week’s show, so we’ll be publishing a longer version in the near future. Look out in your podcast feed for that. In the meantime, Nature has a wealth of content about the Higgs boson’s birthday. Head over to this week’s show notes for links.

Host: Nick Petrić Howe

Talking under pressure is difficult enough for most scientists but for scientists who stutter, it can be even more of a challenge. We'll hear the experience of one researcher and how best to support people who stutter later on. Right now, though, it's time for the Research Highlights with Shamini Bundell.

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Shamini Bundell

Clothes that can both cool a person when they're hot and warm them when they're cold have applications from sportswear to spacesuits. But these garments typically require an external power source or offer limited temperature regulation. To overcome these issues, a team of researchers have designed a garment that integrates an array of ultra-thin, lightweight strips made of metal and plastic into the outer surface of the clothing. When the wearer is warm, these strips curl outwards, allowing the person's body heat to escape to their surroundings. And when the weather is cold, the strips flatten, suppressing such heat transfer. The team say that their clothing could extend the range of external temperatures at which a person would be comfortable by more than 2 °C on both the cold and the hot sides. And they suggest that wearing the clothes indoors would greatly reduce the costs of cooling and heating a building. Try that research on for size in Cell Reports Physical Science.

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Shamini Bundell

Scientists have found that lost DNA from the critically endangered red wolf might be hidden in Louisiana coyotes. Red wolves were once common in the southeastern United States, but are now among the world's most endangered canids. The last known wild red wolves were captured in Louisiana and Texas in the 1980s to establish a breeding programme. But before disappearing from the wild, red wolves interbred with coyotes. Now, to search for hidden wolf DNA, a team of researchers sequenced the genomes of 36 coyotes from Louisiana. The team found that coyotes living in isolated wetlands in southwestern Louisiana have high levels of red wolf DNA, some of which their ancestors had acquired less than 30 years ago, suggesting that red wolves may have survived there into the 90s. The researchers suggest that the high levels of red wolf DNA in these coyotes could make these wetlands a suitable site to reintroduce red wolves into the wild. Read that research in full in Science Advances.

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Interviewer: Nick Petrić Howe

Stuttering, or stammering as we say here in the UK, is a condition that affects around 70 million people worldwide. This speech disorder can make things like speaking in public, or even one-on-one, a lot more daunting. And that is something that scientists do quite a lot of, in high-pressure situations like conferences, lab meetings, or even interviews with journalists. And so, this week in Nature, there’s a careers article about scientists who stutter and how best to support them. To find out more about this, I reached out to Eric Jackson, a researcher of stuttering at New York University, who got into this field because he felt he had a unique insight as someone who stutters himself. I gave him a call and asked him about how others respond to people who stutter and what effect this can have.

Interviewee: Eric Jackson

What often ends up happening is that stuttering turns into an undesirable trait, right? So, people get indications from the people around them that stuttering is something that they should not be doing, and what that results in is a desire to conceal. So much of the experience of stuttering is actually trying to conceal those moments and trying not to stutter and because of that, it can lead to shame and guilt and embarrassment, and certainly something that's going to get stronger over time.

Interviewer: Nick Petrić Howe

Now, that's really interesting because, as I said, we want to talk about scientists who stutter, and one thing scientists do is they give talks at conferences, or they have interviews with people like me, like this, for instance. I guess I'm wondering, what is it like to be in that situation, and what can be done to help support people who have stutters?

Interviewee: Eric Jackson

I think that that's a really good question, and it certainly extends past science as well, right? So, the experience of being put on the spot, or recording a podcast like this, or giving a talk when eyes are on you, it's not like that is what is going to cause stuttering, but it's certainly going to make the experience of it and dealing with it more challenging. For me and science, I've actually had a very positive experience in terms of how my colleagues relate to stuttering because they're all super interested in stuttering and asking me questions about it, which is a good thing because then that informs the kinds of questions that we have. In terms of what people can do, what I typically say is that, well, just speak to a person who stutters how you would speak to anybody else, so not interrupting them, or maybe we interrupt people all the time, right. But maybe when you're speaking with a person who stutters, paying a little extra attention to not interrupting, to listening, to maintaining eye contact, even when a person is in a stuttering block. Besides that, I think that it's up to the person who stutters, in a lot of ways, to let listeners know if there are certain things that the listener can do to make their experience of communicating a little bit easier.

Interviewer: Nick Petrić Howe

And so, thinking about conferences specifically, these can be quite high-pressure moments where people are rushing around, it's very busy, maybe you're giving a talk and that sort of thing. Is there anything that can be done there?

Interviewee: Eric Jackson

So, I think that this is especially related to the kind of like chit chat that happens at a conference, right, which is often the best part of the conference, right? So, like talks generally, maybe, sometimes are okay. But really, it's the in between the talks and the poster sessions where it often seems like everybody's in a rush, everybody wants to kind of get something in, and certainly, that kind of setting can be difficult for a person who stutters, where the time pressure may be heightened. And for me, I think that this process of normalising stuttering, right, and for example, if a person is not used to speaking with people who stutter, it could maybe be pretty uncomfortable for them, right. But the more that stuttering is talked about, the more that it's talked about openly, I think that that'll go a long way in allowing people to feel more comfortable not to interrupt and not to be uncertain of what they should be doing when they're speaking with a person who stutters at a conference. And just tangibly for people who are hearing this who maybe are speaking with a person at a conference who stutters, maybe to put in a little extra attention to kind of staying in the moment with the person who stutters and to like be a better listener for the person who stutters because, in turn, that's going to help to mitigate some of that time pressure that a person who stutters feels.

Interviewer: Nick Petrić Howe

And for you personally, what have you found useful in these sorts of situations?

Interviewee: Eric Jackson

So, my own personal journey with stuttering has probably mostly benefited from changing how I think about stuttering as a thing that you're not supposed to do, to a thing that sometimes happens. Because when it's not something that you're supposed to run away from or to try to conceal, then you could learn to be more present in the moment, which is going to positively impact confidence and self-esteem and all of those other things. And it's going to make you more likely to engage in all aspects of your life, right? So, scientific conferences being one of those, of course, but really, it applies across the board.

Interviewer: Nick Petrić Howe

And one thing, as well, that you talk about in the article is this idea that stuttering is somehow pathologised in the field. Can you tell me a little bit about that?

Interviewee: Eric Jackson

Yeah, so I think it is just natural for scientists who study disorders to use the type of terminology that includes healthy controls, right? Certainly, all of these colleagues are probably well intentioned and they don't mean anything by it, but what is happening with use of the term ‘healthy controls’ is that you're saying, ‘Okay, well, then that must mean that the stuttering group is not healthy.’ It's kind of medicalising the problem, where stuttering is not a medical issue, right. It's this condition that sometimes interrupts the forward flow of speech. So, I think it's a little bit of a microaggression that I've been trying to get out there that, okay, well, why don't we just call them the stuttering group, right, or the group who stutters, as opposed to kind of putting this label that implies that there's some kind of medical illness there.

Interviewer: Nick Petrić Howe

So, after speaking to you and reading the article, if I were to have one takeaway, I guess it would be that we should all become more respectful and better listeners.

Interviewee: Eric Jackson

I think that that's a great way to sum it up, Nick, yes. And actually, one interesting thing about stuttering is it helps a person become a better listener, right? Because most of us, by default, could be better listeners, right? And this experience of sort of knowing what you want to say, when you want to say it, but for some reason your body, in that particular moment, breaking down, and like knowing that that's a possibility, I think that it gives people who stutter and an especial appreciation for the art of listening.

Interviewer: Nick Petrić Howe

That was Eric Jackson, from New York University in the US. For more on this topic, check out the show notes for a link to the careers article.

Host: Benjamin Thompson

Finally on the show, it's time for the Briefing chat, where we discuss a couple of articles that have been featured in the Nature Briefing. And before we start, just for the benefit of the listeners, Nick, I think it's worth saying this is the first one of these we've done, in person, in the same space, in what, three years, I think?

Host: Nick Petrić Howe

It must be. It must have been before the pandemic kicked off. And it's very weird to be doing this whilst looking directly at your face in 3D. It's very strange, but it's good because the story that I was reading this week in New Scientist is all about being in person and sort of close contact because it's sort of about how people smell.

Host: Benjamin Thompson

Right, and also for the benefit of the listeners, I will say that Nick hasn't sort of reached over the desk here to give me a sniff. But tell me what's going on with this story then.

Host: Nick Petrić Howe

Well, maybe I haven't yet, but maybe I did when we first met because this story is all about how people who have similar odours seem to click and become instant friends a lot more quickly than people who do not have such similar odours.

Host: Benjamin Thompson

So, if we smell the same, we're more likely to be buddies. Is that what you're saying?

Host: Nick Petrić Howe

Yeah, this research is really about that sort of instant connection that you sort of feel with people sometimes where you’re like, ‘I really clicked with that person.’ And these researchers are saying, well, maybe it's because you gave him a good sniff and you were like, ‘Well, smells similar to me.’ So, previous research has shown that when we first meet people, we actually unconsciously sniff them. So, you may have shook their hand or something like that, and you may lift the hand to your nose without even realising it, and give it a smell, and that may be giving us all sorts of signals. It's very common in other animals, for example. And so, this research, it got 20 pairs of people together who had said they had clicked on first meeting, and then it took their T-shirts, and sniffed them with an electronic nose – something that's able to determine what the chemical composition of the smells are – and also got some human volunteers to sniff the T-shirts as well, and say how they smelt. And those people who clicked instantly had much more similar smells than those people who didn't because they also had a group where they'd sorted them randomly together, and they were just random groups of people and they didn't smell alike.

Host: Benjamin Thompson

I mean, that's quite something, Nick. Have the researchers behind the work given any insight into why people who kind of smell similar might get on better than those who don't?

Host: Nick Petrić Howe

It's a bit of a mystery, to be honest, but they've given some sort of hints. For example, as I mentioned, other animals – dogs are the famous example – sniff each other to determine who's a friend and who's a foe, so it could be something like that. And also, previous research has shown that we tend to become friends with people who are similar to us, like they’re similar ages or education level, that sort of thing, so it could be an aspect of that. But the interesting thing is, in heterosexual people, when they're attracted to people, they tend to be attracted to people who smell different to them, so it seems to be this is something just for friendship when you smell alike.

Host: Benjamin Thompson

Right, well, that is an interesting one, and I'm sure we'll be sniffing out some more information when it arrives. Well, listen, let's stick in kind of the smell arena, if we may, for my story this week, and this is something that I read about in Nature and it's based on a paper in Cell, and it's about how odour can affect how mosquitoes bite. Now, I know we've talked about this on the podcast not too long ago, but this story is neat because it's about how viral infections can change our smells and maybe make us more attractive to mosquitoes.

Host: Nick Petrić Howe

Okay, so this is not about being attractive to other people, but to mosquitoes. Now, it does remind me that study you did, but that was about humans being more attractive than other animals, and this is viruses can change it. So, how does the virus change your sort of smell makeup?

Host: Benjamin Thompson

Well, this is very strange indeed, Nick, and the viruses we're talking about specifically are Zika and dengue, right, which can cause very serious disease, and millions of people are affected by them every year. Now, a lot of this work is done in mice, but there are some human aspects as well. Now, I will say that it's been known that microorganisms that cause disease can alter the smells of their hosts, right. So, for example, the malaria parasite can make humans smell different, and mosquitoes are more attracted to them. And apparently, cucumber mosaic virus can make plants more attractive for aphids, who can then go and pass the disease on in other places. And now, I think we can add Zika and dengue to that list. And this experiment, what they did is they looked at mice, okay, and they infected mice with Zika or dengue, and then they wafted air over them and compared this wafted air to uninfected controls, and saw what kind of effect that had on mosquitoes. And what they showed is the mosquitoes really, really preferred the smell of the infected animals and would go towards them much more preferentially than the uninfected mice.

Host: Nick Petrić Howe

Right, and you said there that in some cases this has helped microorganisms spread themselves around. Is that what's going on here, do the researchers think?

Host: Benjamin Thompson

I think that's what they're working on, Nick, but it gets even more interesting in terms of the microorganisms. So, analysis showed that the infected mice gave off a bunch of smelly compounds, right, but one in particular, this airborne molecule called acetophenone, and I hope I'm pronouncing that correctly, and the infected mice gave that off ten times as much. And now, this is where we need to strap in a little bit because this molecule is made by bacteria that live on the skin, and these grow naturally and the numbers are kept in check by an antimicrobial that is produced by the skin, okay? Now, in the infected mice, the team showed that the gene responsible for making this antimicrobial compound was less active, so more of these skin bacteria could grow, which in turn made more of this acetophenone compound which, in turn, attracted more mosquitoes.

Host: Nick Petrić Howe

So, the virus stopped the antimicrobial activities going on in the skin, so there were more of these bacteria, and so they gave up more of this compound, and that then attracts mosquitoes.

Host: Benjamin Thompson

Seemingly so, and it turns out that humans infected with dengue produce more acetophenone as well, adding some more weight to the fact that this is kind of the key to what's going on in this instance.

Host: Nick Petrić Howe

And when we're talking about mosquitoes and certainly disease spread, the thing that always pops into my head is disease control and sort of preventing the spread of it. Can this information help us design interventions that will help stop the spread of these diseases?

Host: Benjamin Thompson

So, it seems like that might be the case. What the team showed is that giving mice a vitamin A derivative, okay, now this is used to treat skin conditions, what this did is it helped lower the amounts of the acetophenone produced. So, it made these mice less attractive to the mosquitoes. So, it's a strange one, right, but it might be that this could be used in future as some sort of way to reduce transmission. And indeed, this team plan to test the use of vitamin A to reduce the transmission of dengue in Malaysia, where it is endemic. And there are potentially some other things as well. You mentioned an artificial nose earlier. It could be that being able to smell this compound or to check for it really quickly could be a way to diagnose someone who has a Zika or a dengue infection. And as I say, these viruses infect millions of people a year, so it's a serious health burden, and this work could provide some new insights that could have some real-world applications.

Host: Nick Petrić Howe

I mean, let's hope so. It will be great to have better control of these diseases. So, thank you, Ben, for bringing that to the Briefing chat. And listeners, for more on these articles and for where to sign up to the Nature Briefing to get more stories like them, make sure you check out the show notes.

Host: Benjamin Thompson

That’s all for this week, but as always, you can keep in touch with us on email – we’re podcast@nature.com – or on Twitter – @NaturePodcast. I’m Benjamin Thompson.

Host: Nick Petrić Howe

And I’m Nick Petrić Howe. Thanks for listening.