The detector Compact Muon Solenoid (CMS) in a tunnel of the Big Collider of Hadrons.Picture: VALENTIN FLAURAUD / AFP (Getty Images)
On July 4, 2012, CERN scientists confirmed the observation of the Higgs boson, an elementary particle first proposed in the 1960s. The discovery of the boson was a momentous occasion, as it meant that physicists they were one step closer to probing the field associated with the boson, which gives too much to the particles.
But since 2012, particle physics has not had any other seismic events. Important discoveries have been made: measurements of the behavior of the muon in a magnetic field were taken, the mass of the W boson was measured more accurately, and new particles have been discovered, but nothing as surprising as the Higgs confirmation.
But we are not pessimistic: there are currently many fascinating experiments underway that can offer the next big leap in our understanding of the subatomic universe. So we asked several physicists where they think this breakthrough can happen. The following responses have been condensed and edited slightly for clarity.
Rice University physicist and collaborator of the CMS experiment at CERN
The next big thing in physics will be a better understanding of dark matter. A number of facilities will be activated and will allow us to explore the nature of dark matter significantly better than has been achieved so far. For example, the High Luminosity-LHC will increase by an order of magnitude the number of Higgs bosons we will have to study, and we will be able to study their properties with tremendous accuracy.
This in turn will give us a new window through which to explore the dark matter that permeates the universe, as any deviation from the predictions of the standard model will tell us the direction of the new physics involved. Other new facilities, such as the Cosmic Microwave Background Stage 4 (CMB-S4), will operate in a similar period of time. It will be possible to combine the results of these different installations to paint our best image so far of the dark matter that permeates the universe.
“The next big thing in physics will be a better understanding of dark matter.”
Theoretical cosmologist at the University of Chicago
Here are five possibilities, at least as good as the Higgs.
1) Discovery of the dark matter particle. We have an airtight case where there is 5 times more matter than atoms (in any form) can explain (> 50 sigma). We have good candidates, the lightest particle of supersymmetry and axion, and we experiment with the ability to make a discovery. The problem of dark matter has been with us for almost 100 years and is ripe to be solved. Whenever it is, we will close a mystery, discover a new form of matter, and open a new door to study the first microsecond of the Universe. What more can you ask for!
2) Discovery of the signature of gravitational waves produced by inflation in the polarization of the cosmic microwave background. If the “mode B” polarization signature is discovered and confirmed, this would tell us when inflation occurred in addition to being the oldest relic in cosmology. (If detected, these gravitational waves would have occurred when the Universe was 10 ^ -36 seconds old.) It is not an easy task, but the experiments / experimenters are up to the task: the signal is the level of nanoKelvin to CMB. (whose temperature is 2.76 K).
3) Confirmation that the Hubble discrepancy is real. That is, the rate of expansion measured directly today is not equal to that measured at 400,000 years (cosmic microwave background measurements) and extrapolated forward using our current cosmological paradigm (Lambda CDM). Both measurements may be correct if something is missing in Lambda CDM.
4) The discovery of supersymmetry at CERN. A whole new world of particles and the first big home run for superstring theory.
5) Something unexpected in the Gravitational Wave Observatory with laser interferometer (LIGO). As we know and like to say, it is the unexpected discovery in a new installation such as the LIGO or the telescope or accelerator that transforms the most. LIGO has been a fantastic success, but all the events it has discovered were the ones predicted: coalescences of two black holes, two neutron stars and one black hole and one neutron star. How about a surprise? (e.g., mid-1960s pulsars or quasars)
I won’t even mention signs of life elsewhere (e.g., Venus, a moon of Jupiter or Saturn, or the atmosphere of an exoplanet). This will happen, the only question is when and where.
“… we will close a mystery, discover a new form of matter and open a new door to study the first microsecond of the Universe. What more can you ask for!”
Particle physicist at the University of Hamburg and collaborator of the CMS and FCC-ee collaborations
So this is also a kind of challenging situation we were in, in which we were not when we were dealing with the Higgs boson of the standard model. With the standard model Higgs boson, you basically had a nice puzzle and you miss this piece. You knew the shape of the piece, and then you looked at the box and found the shape of the piece and put it on. What we have now is a box full of 3D or possibly 2D puzzle pieces. You’re not really sure. And they just said, “Yeah, there should be something.” Have fun.’
According to the standard model, the frequency with which the Higgs boson interacts or dissolves, these two things are interchangeable for particle physicists, this depends on the mass of the other Higgs particle. This means that you can predict (if you know the mass of all these particles) how often they should be done. When you make a Higgs boson, often the Higgs boson should make these particles. And that’s the kind of thing we’ve been checking over the last year: seeing the Higgs boson decay into Z bosons, seeing the Higgs boson decay into W bosons, seeing it decay into Tau leptons, into B quarks. , if it interacts with the upper quarks. Recently, which can decay into muons, these kinds of things are tests of the internal consistency of the standard model in the hope that we find something inconsistent, which will guide us to see where the standard model begins to break down.
There are a few very exciting dark matter experiments that will be back online. If they see something, [the LHC] we can change our selection so we can check if we can also play it consistently. And that’s because these particle detectors are really good at this: once you know what you’re looking for, it’s very easy to find an algorithm to isolate these particles.
I am referring to the Xenon experiment and the LUX-Zeplin experiment. Both have been updated over the last few years and are now back online. These experiments are large xenon tanks (which is why they all have X in their name), and they all expect the Earth to move through dark matter and the experiment is on Earth, and that dark matter will be Xenon Atom and they can detect this bouncing atom.
The expectation that such experiments will produce something innovative, winning the Nobel Prize every five years is unrealistic. This is a long-term science where you need to plan things and you need big data sets that are extremely difficult to analyze.
“With the standard model Higgs boson, you basically had a nice puzzle and you are missing this piece … What we have now is a box full of 3D or possibly 2D puzzle pieces. You’re not really sure.
Particle physicist at Nikhef and collaborator of the LHCb experiment at CERN
We are currently preparing for the LHC reboot with a new LHCb detector (called “LHCb Upgrade I”), so all we are excited about is getting the new detector up and running as well as the data processing chain. , which is what I work on.
The main goal for us will be to identify “taste abnormalities” in particles that contain quarks b. I am very excited that these show a discrepancy with the standard model: it seems that there are too few b quarks that transform into pairs of muons compared to electrons. I started this study at LHCb 10 years ago, so I will be watching it very closely. The huge amount of data we will collect in the next 10 years will tell us.
If this is true, it requires a new force of nature associated with (at least) a new boson. It could be a Z boson, similar to the well-known Z, or something completely different, like leptoquarks (or both). Either way, this would be a revolution in particle physics.
The next question is whether these new particles can be produced at the LHC. There are some “shocks” to the data shown by ATLAS and CMS collaborations at the Moriond conference in March. These may be the first signs of new particles causing taste abnormalities. But experience has shown that these blows disappear with more data. So let’s see.
If the LHC has too low an energy to produce these new bosons, we need another machine. This could be the brute force of the Future Circular Collider (FCC) and its 100 km and energy 7 times greater than the LHC. Or a much smaller but more challenging muon collider. Depending on the cause of the anomalies (still hoping they survive the scrutiny with more data), a muon collider may be the ideal tool: if we have a problem with muons, we use muons to find out -ho.
“There are some ‘bumps’ in the data shown by the ATLAS and CMS collaborations … These may be the first signs of the new particles causing the taste anomalies.”
Physicist at Texas A&M University and spokesman for the CDF collaboration
I see two great potential advances in physics over the next 10 years in physics. The first is that with the recent observation of the CDF experiment at Fermilab that the mass of the W boson is at 7 standard deviations from expectations, there will be a global focus on this potential rupture in the standard particle model …