by Daniel Ang
figures by Aparna Nathan

Particle physics says that the universe shouldn’t exist.

This is a radical claim! But if the current theories that underlie particle physics are correct and complete, then the Big Bang that birthed the universe would have simply resulted in a massive flash of light. Nothing else would remain – no stars, planets or galaxies. And neither you nor I would be around to read this text.

Why does particle physics conclude that the universe shouldn’t exist? In this article, we will explore the most widely accepted theory in particle physics – the Standard Model- our inability to find any significant new physics beyond it, and the implications for our overall understanding of the universe.

Why the Standard Model is important

Particle physics is the study of subatomic particles and their interactions with one another. These include protons, neutrons, and electrons, which are the basic constituents of most naturally occurring matter, as well as more obscure particles such as muons and neutrinos, which can only be produced in significant amounts artificially. Some subatomic particles like protons and neutrons are made of fundamental particles called quarks. Others such as electrons are considered fundamental particles in their own right. While we cannot see any of these particles with our naked eye, they give rise to the nature and properties of all the macro-level matter around us (Figure 1).

Figure 1: The connection between everyday matter and the subatomic realm. Ordinary objects are made of atoms, which consist of a nucleus and orbiting electrons. The nucleus consists of neutrons and protons, which in turn consist of quarks bound together by gluons.

Throughout the 20th century, particle physics progressed rapidly, from Rutherford’s discovery of the structure of the atom (1911) all the way to the development of the Standard Model (SM), a theoretical framework that incorporates the 17 types of known fundamental particles and their interactions (Figure 2). As a theory, the SM has been very accurate, giving predictions that have been borne out by multiple experiments. Its latest major victory was the discovery of a new particle called the Higgs boson – the last fundamental particle proposed by the model that had not previously been directly observed. The SM currently represents our best understanding of the universe. In almost all of our experiments, we have not been able to find definite signs of new physics beyond the SM. But, as we shall see, this theory has some fundamental problems, as it fails to explain major natural phenomena in our universe.

Figure 2: The 17 fundamental particles of the Standard Model. Protons and neutrons that we regularly encounter around us are made of combinations of quarks. Some other particles such as muons can only be created artificially in the lab, while neutrinos are ubiquitous around us but so tiny that they rarely interact with anything they pass through.

The problem of dark matter

One of the limitations of the Standard Model is the existence of dark matter: mysterious masses of matter that do not reflect light and are thus invisible to the naked eye and  telescopes. However, we can infer the presence of dark matter through its gravitational interaction with normal, light-reflecting matter, which results in anomalies like altered galaxy rotation curves. It is unlikely that dark matter consists of any of the particles in the SM. Rather, the most probable explanation for this evidence would be the existence of as-of-yet undiscovered particles that behave and interact differently than those outlined in the SM.

Many experiments have been designed to look for these new particles. For example, dark matter experiments LUX and XENON1T use a large tank of liquid xenon to find experimental evidence for the existence of a hypothetical dark matter particle called a WIMP, or a Weakly Interacting Massive Particle. If such a particle were to pass through the tank, it would interact with the xenon and produce a flash of light that is picked up by detectors. Unfortunately, despite over a decade of similar searches, no WIMPs have been detected by either experiment. Nor have any other dark matter experiments detected a clear, unambiguous signal of new particles. While this does not rule out all the range of possibilities of dark matter, null results like these have already constrained many simpler classes of theories.

In light of our failure to verify any of our proposed theories about dark matter with experimental evidence, we have to make do with the fact that there is a great hole in our understanding of matter in the universe. Still, can’t we at least be satisfied that the Standard Model describes ordinary, everyday matter – protons, neutrons, electrons – very well?

Unfortunately, the answer is: not quite.

The problem of baryon asymmetry

In the beginning of this article, I described how the Standard Model tells us that instead of stars and galaxies, there should only be pure light. To understand why this is the case, we have to talk about antimatter, a new type of matter different from ordinary matter and dark matter. Antimatter has certain properties that are opposite to ordinary matter (which we shall henceforth just call matter) but otherwise seems exactly the same. The first antimatter particle discovered was the positron (1932), whose properties such as mass and magnetism are identical to the more familiar electron. The only difference is that its charge is positive instead of negative. In addition, when matter and antimatter come into contact with one another, they annihilate, leaving only pure energy mostly in the form of photons.

As we know that antimatter is the perfect opposite of matter, if the Standard Model is a complete theory, the Big Bang should have produced equal amounts of matter and antimatter. These two different, opposite types of matter would mix with each other and annihilate, resulting in a bath of pure, formless energy, mostly light (Figure 3).

Figure 3: two scenarios depicting the evolution of the universe with or without asymmetric processes. In the first, the Big Bang occurs assuming only Standard Model physics (top left), resulting in equal amounts of matter and antimatter being produced, which annihilate to result in a universe of pure photons (top right). In the second scenario, asymmetric processes not predicted by the SM result in the production of more matter than antimatter (bottom left), giving the universe we know today, filled with stars, planets, and numerous other objects (bottom right).

Of course, the reality is that we have more than just light in this universe. So there must be some missing piece in the puzzle. Specifically, there must be asymmetric processes happening in the universe that produce more matter than antimatter. After the Big Bang, matter would win out, leading to the abundance of galaxies and planets we see today. This is called the baryon asymmetry problem.

What are these asymmetric processes? The SM does contain some processes that would result in a tiny bit more matter being produced than antimatter. But it is far from enough to explain the amount of matter we see today. Thus, if there is no new physics beyond the SM, particle physics would have no good explanation for baryon asymmetry, utterly failing in its goal to explain the origin, nature, and behavior of matter.

In response to this quandary, particle physicists run experiments to look for new asymmetric processes beyond what is predicted by the SM. In the Large Hadron Collider, particles are smashed together at high speeds in hopes of observing these asymmetric processes. In 2017, some evidence was found of particle decays that result in more matter than antimatter. However, it remains to be seen whether these results are sufficient to completely solve the baryon asymmetry problem. Similarly, experiments like the ACME EDM experiment also investigate these asymmetric processes by looking at their effects on fundamental particles, such as the charge distribution of the electron. However, despite the incredible degree of precision achieved, the most recent ACME EDM result failed to find evidence that explains baryon asymmetry.

A never-ending search

As we have seen, the Standard Model presents us with a conundrum. Because it cannot explain the evidence of dark matter nor baryon asymmetry, we are almost sure that it has to be wrong at some level. Yet, every time we get into the laboratory to pinpoint exactly how it fails, we have come up empty handed. In other words, there seems to be a great tension at the heart of particle physics!

Will the answer to this conundrum be lying around in the corner, in the next magnitude of improvement in precision in these experiments, or is it impossibly distant, forever inaccessible without recreating the Big Bang itself? We can only hope that it is the former, as I think the human capacity to keep asking these great questions will never be exhausted.

Daniel Ang is a fourth-year graduate student in physics at Harvard University who works on the ACME EDM experiment.

Aparna Nathan is a second year Ph.D. student in the Bioinformatics and Integrative Genomics program at Harvard University. 

For more information:

  • To learn more about the Standard Model, see this article hosted by CERN. The Particle Adventure is also a great guide to what particle physicists do and what questions they are interested in.
  • To learn more about dark matter, see this past SITN article.
  • This article by Eric Sather gives an excellent explanation of how the asymmetric processes mentioned above (the technical term is CP violation) can give rise to baryon asymmetry.
  • See here for more information on the experiments investigating baryon asymmetry at the Large Hadron Collider, as well as an excellent explanation of CP violation.
  • To learn more about the ACME EDM experiment, see this past SITN article. See here also for a series of blog posts that I have written to explain the experiment in an understandable way to a general audience. See here for an update on the latest finding of the ACME EDM experiment.

14 thoughts on “The Frustrating Search for New Physics

  1. Dark matter is a supersolid that fills ’empty’ space, strongly interacts with ordinary matter and is displaced by ordinary matter. What is referred to geometrically as curved spacetime physically exists in nature as the state of displacement of the supersolid dark matter. The state of displacement of the supersolid dark matter is gravity.

    The supersolid dark matter displaced by a galaxy pushes back, causing the stars in the outer arms of the galaxy to orbit the galactic center at the rate in which they do.

    Displaced supersolid dark matter is curved spacetime.

    1. There is evidence of the supersolid dark matter every time a double-slit experiment is performed as it is the supersolid dark matter that waves. Wave-particle duality is a moving particle and its associated wave in the supersolid dark matter.

      In the following video, the vibrating silicon substrate represents the chaotic supersolid dark matter.

      In a double slit experiment the particle always travels through a single slit and the associated wave in the supersolid dark matter passes through both. As the wave exits the slits it creates wave interference which alters the direction the particle travels as it exits a single slit. Over time the particles form an interference pattern. Strongly detecting the particle exiting a single slit destroys the cohesion between the particle and its associated wave, the particle continues on the trajectory it was traveling and does not form an interference pattern.

      The supersolid dark matter ripples when galaxy clusters collide and waves in a double-slit experiment, relating general relativity and quantum mechanics.

      1. ‘The Milky Way’s dark matter halo appears to be lopsided’

        > “the dark matter halo of the Milky Way is dominantly lopsided in nature.”

        The Milky Way’s halo is lopsided due to the ordinary matter in the Milky Way moving through and displacing the supersolid dark matter, analogous to a submarine moving through and displacing the water.

        1. In the following articles the fluid is the chaotic supersolid. dark matter.

          ‘Fluid mechanics suggests alternative to quantum orthodoxy’

          > “The fluidic pilot-wave system is also chaotic. It’s impossible to measure a bouncing droplet’s position accurately enough to predict its trajectory very far into the future. But in a recent series of papers, Bush, MIT professor of applied mathematics Ruben Rosales, and graduate students Anand Oza and Dan Harris applied their pilot-wave theory to show how chaotic pilot-wave dynamics leads to the quantumlike statistics observed in their experiments.”

          ‘When Fluid Dynamics Mimic Quantum Mechanics’

          “If you have a system that is deterministic and is what we call in the business ‘chaotic,’ or sensitive to initial conditions, sensitive to perturbations, then it can behave probabilistically,” Milewski continues. “Experiments like this weren’t available to the giants of quantum mechanics. They also didn’t know anything about chaos. Suppose these guys — who were puzzled by why the world behaves in this strange probabilistic way — actually had access to experiments like this and had the knowledge of chaos, would they have come up with an equivalent, deterministic theory of quantum mechanics, which is not the current one? That’s what I find exciting from the quantum perspective.””

          It is the chaotic nature of the supersolid dark matter which causes the Casimir effect.

          1. ‘Astronomers Discover New Galaxy That Is 99.99% Dark Matter’

            > “A relatively large fraction of the stars is in the form of very compact clusters, and that is probably an important clue.”

            The more compact the cluster the greater the displacement of the supersolid dark matter connected to and neighboring the cluster, the greater the displaced supersolid dark matter pushes back and exerts pressure toward the cluster, the faster the stars in the cluster move.

            ‘Scientists Thought All Galaxies Had Dark Matter, but They Just Found One Without It’

            > “DF2 upends current theories about how galaxies form, which predict that the gravity of dark matter is necessary for early galaxies to hang together.”

            The reason for the mistaken notion the galaxy is missing dark matter is that the galaxy is so diffuse that it doesn’t displace the supersolid dark matter outward and away from it to the degree that the supersolid dark matter is able to push back and cause the stars far away from the galactic center to speed up.

            It’s not that there is no dark matter connected to and neighboring the visible matter. It’s that the galaxy has not coalesced enough to displace the supersolid dark matter to such an extent that it forms a halo around the galaxy.

            A galaxy’s halo is not a clump of dark matter traveling with the galaxy. A galaxy’s halo is displaced supersolid dark matter.

          2. ‘Robert B. Laughlin, Nobel Laureate in Physics, endowed chair in physics, Stanford University, had this to say:’

            > “the empty vacuum of space … is filled with ‘stuff’ … The modern concept of the vacuum of space, confirmed every day by experiment, is a relativistic ether. ”

            Laughlin’s relativistic ‘stuff’ is the supersolid dark matter. The state of the supersolid dark matter determines the rate at which an atomic clock ticks. The state of the supersolid dark matter determines the relativistic effects.

          3. ‘Einstein: Ether and Relativity’

            > “the state of the [ether] is at every place determined by connections with the matter and the state of the ether in neighbouring places”

            The state of the supersolid dark matter at every place determined by its connections with the ordinary matter and the state of the supersolid dark matter in neighboring places is the state of displacement of the supersolid dark matter.

          4. ‘NASA’s Gravity Probe B Confirms Two Einstein Space-Time Theories’

            > “Imagine the Earth as if it were immersed in honey. As the planet rotates, the honey around it would swirl, and it’s the same with space and time”

            Honey has mass and so does the supersolid dark matter. The swirl is the state of displacement of the supersolid dark matter connected to and neighboring the Earth.

          5. The “missing mass” associated with dark matter is the mass of the supersolid dark matter that is connected to and neighbors the ordinary matter which is displaced by the ordinary matter.

          6. The Bullet Cluster collision is analogous to two boats that crash into each other, the boats stop and their bow waves continue to propagate. The galaxies are moving through and displacing the supersolid dark matter. When the galaxies collide their associated dark matter displacement waves continue to propagate.

          7. What physicists mistake for the Bullet Cluster “matter distribution calculated from gravitational lensing” is actually the gravitational lensing caused by the associated dark matter displacement waves propagating away from the colliding galaxies.

  2. The search for a New Physics is routinely mirrored by ignorance of breakthrough findings like cold fusion, room temperature superconductivity, overunity and antigravity, which just point to scalar wave physics of Nicola Tesla. So that the actual progress is hidden in just the areas of physics, which are currently ignored and dismissed the most.

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