Breakthrough in Nuclear Physics: Strong Interaction Between Stable and Unstable Particles

Particle Collision Proton Hyperons

Using collision data from the ALICE detector at the Large Hadron Collider at CERN, the strong interaction between a proton (right) and the rarest of the hyperons, the omega hyperon (left), which contains three strange quarks, was successful measured with high precision. Credit: Daniel Dominguez / CERN

High-precision measurements of the strong interaction between stable and unstable particles.

The positively charged protons in atomic nuclei should actually repel each other, and yet even heavy nuclei with many protons and neutrons stick together. The so-called strong interaction is responsible for this. Prof. Laura Fabbietti and her research group at the Technical University of Munich (TUM) have now developed a method to precisely measure the strong interaction utilizing particle collisions in the ALICE experiment at CERN in Geneva.

The strong interaction is one of the four fundamental forces in physics. It is essentially responsible for the existence of atomic nuclei that consist of several protons and neutrons. Protons and neutrons are made up of smaller particles, the so-called quarks. And they too are held together by the strong interaction.

As part of the ALICE (A Large Ion Collider Experiment) project at CERN in Geneva, Prof. Laura Fabbietti and her research group at the Technical University of Munich have now developed a method to determine with high precision the forces that act between protons and hyperons, unstable particles comprising so-called strange quarks.

The measurements are not only groundbreaking in the field of nuclear physics, but also the key to understanding neutron stars, one of the most enigmatic and fascinating objects in our universe.

Comparison between theory and experiment

One of the biggest challenges in nuclear physics today is understanding the strong interaction between particles with different quark content from first principles, that is, starting from the strong interaction between the particles’ constituents, the quarks and the gluons, that convey the interaction force. 

The theory of the strong interaction can be used to determine the strength of the interaction. However, these calculations do not provide reliable predictions for normal nucleons with up and down quarks, but for nucleons that contain heavy quarks, such as hyperons which contain one or more strange quarks.

Experiments to determine the strong interaction are extremely difficult because hyperons are unstable particles that are rapidly decaying after production. This difficulty has so far prevented a meaningful comparison between theory and experiment. The research method deployed by Prof. Laura Fabbietti now opens a door to high-precision studies of the dynamics of the strong force at the Large Hadron Collider (LHC).

Measurement of the strong force even for the rarest hyperon

Four years ago, Prof. Fabbietti, professor for Dense and Strange Hadronic Matter at TUM, proposed to employ a technique called femtoscopy to study the strong interaction at the ALICE experiment. The technique allows investigating spatial scales close to 1 femtometer (10-15 meter) – about the size of a proton – and the spatial range of the strong-force action.

Meanwhile, Prof. Fabbietti’s group at TUM managed not only to analyse the experimental data for most of the hyperon-nucleon combinations, they also succeeded in measuring the strong interaction for the rarest of all hyperons, the Omega, consisting of three strange quarks. Furthermore, the group also developed their own framework that is able to produce theoretical predictions.

“My TUM group has opened a new avenue for nuclear physics at the LHC, one which involves all types of quarks, reaching an unexpected precision in a place nobody has looked so far,” says Prof. Fabbietti. The work published now in “nature” presents only some of the many interactions measured for the first time.

Do neutron stars contain hyperons?

Understanding the interaction between hyperons and nucleons is also extremely important for testing the hypothesis of whether neutron stars contain hyperons. The forces that exist between the particles have a direct influence on the size of a neutron star.

So far, the relationship between the mass and the radius of a neutron star is unknown. In the future, Prof. Fabbietti’s work will therefore also help to solve the riddle of the neutron stars.

Reference: “Unveiling the strong interaction among hadrons at the LHC” by ALICE Collaboration, 9 December 2020, Nature.
DOI: 10.1038/s41586-020-3001-6

The collaboration ALICE (A Large Ion Collider Experiment) counts more than 1000 scientists from over 100 physics institutes in 30 countries. The following German institutions are involved: University Bonn, University Frankfurt, GSI Helmholtzzentrum für Schwerionenforschung, University Heidelberg, University Münster, TUM, University Tübingen and Hochschule Worms. In Germany, ALICE receives funding from the BMBF and the GSI Helmholtzzentrum für Schwerionenforschung.

10 Comments on "Breakthrough in Nuclear Physics: Strong Interaction Between Stable and Unstable Particles"

  1. Really interesting stuff it brings us to ultimate reality of infinate light

  2. …⛱ …

    • Philippe Martin | December 13, 2020 at 12:13 pm | Reply

      Bravo, et deux fois Bravo. Dur labeur Sais plus que payant. Bravo encore une fois. Vous tous sela est sincèrement le fruit d’une nouvelle épopée. Sincères amitiés Philippe Martin 😎🎶

  3. Strangeness was invented to accommodate non-strong interaction phenomena. If omega interacts with protons, it cannot be fully strange or proton is not totally non-strange or both. Either way strangeness loses its meaning.

  4. Eric L. kopchia | December 13, 2020 at 11:35 pm | Reply

    If like to shed some light on what all photons are made of and new forces involved. I estimate the photons must spin either in equitorial direction it a dipole direction
    But the photons has to gain momentum in order to spin in either angular direction. So new forces are the EQ spin and dipole spin and differential force and the energy force to sustain all light and then all matter. But has to be in.a six axis arrangement and 36 to 42 micro photon particles to start the spinning motion. But it starts by having a complicated wave propagation from all 7 forces to be complete in its conceptual firm and theory

  5. Sisanta Chhatoi | December 14, 2020 at 2:45 am | Reply

    Bravo!!!Guys,great,
    Physics the father of all.

  6. Sekar Vedaraman | February 14, 2021 at 4:01 pm | Reply

    Outstanding . Fabulous Research by Prof. Laura Fabbietti! AND the ALICE Team.

    ALICE has finally entered the Wonderland. Guess What? The Mad Hatter who is Present with numerous Theories he pulls out of his hat which ALICE needs to Prove and or Disprove.

    Reimagine Strong Nuclear Forces and Weak Nuclear Forces.

    Q Why do we call them unstable hadrons? Just because they have fleeting existence! Time and Space are both infinitesmally smalle in the Quantum World , so this measureent is the first step in really understanding the “Theory of Eveything” !

    Let us first understand Magnetism. In Magnetism at the Gross Level both the attractive and repulsive forces exist in equilibrium at each pole. In Magnetism at the atomic level and magnetism at the sub-atomic levels, if we extend this logic of existence in Eqilibrium , the Quantum World exists in Equilibrium with the Gross world in which we exist.

    Next understand Electromagnetism. The role of electrons in the same is fairly well understood. Maxwells principles are fairly well understood from high School physics.Columbs….

    What exactly are we doing when we accelerate the various particles at very high speeds approahing the speed of light using a cyclotron, and getting them to collide and examining the outputs which are sub -atomic partiicles of various shades and nature…..

    Assumptions we make cloud our thinking . Here too we are letting our natural bias for linerailty and time spans as we know it, to define stable particles and unstable particles!
    Why cannot non-linear Quarks exist rather than just Up and Down Quarks?

    If we can conduct such measurements why cant we reimagine Fusion itself at Room Temperatures. Cold Fusion, you ask? Yes. Find out which sub-atomic particles interactions of attractions and repulions can result in this phenomenon at room tempearue!! AND Produce an Inexhaustible Source of Energy for Humanity. Well Fusion is happenning in the Sun but as very high temperatures. If we can make it happen at room temperature , wouldn’t that be great.

    Finite Space-Time is a sub-set of Infinite Space -Time. Work out the mathemtics of infinite space time ( Either OR AND BOTH) ! Corelate it with Mattter- Energy Equation of Einstien — E = MC Squared. In my opinion Matter is equivalent to Energy stored in Potential Form and Energy is the Kinetic Version of Mass. Light can Exist in both Forms. Particle and Wave. The Speed of Light is the Connecting Piece in this Puzzle. Or is it? Are there other forces?

    Solve the Mathematics of this and we will have the ability to predict what sub-atomic particles will exist as we keep doing these collision eperiments and which collision would release maximum energy at minimum effort of temperature and pressure etc. so that the dreaam of Cold fuson at room temperature can be made into a reality. Basically a engineering problem after that , once the Science is established.

    This Measurement of Quark with higher Mass exhibiting Space-Time Latice behaviour is predictable. What would be even more interesting would be to see the results of Quark with less mass and more energy and its behavious certainty and uncertainty results. I would predict lees certainty and Less Mass – Latice Certainty though —- if it exhibits similar Behaviour what it means is there is NO Difference between Mass AND Energy! Einstiens theory would be proved. However if it exhibits different behaviour it opens up an entire realm of possibilities. This includes Speeds greater than the Speed of Light.

    Statistics and Correlation

    Distances and Time in thw Quantum is FAR FAR Different from the same in the Gross World.

    Good to see thinig progressing beyond a Coorelation of Zero and One as he limit. The Data related to Correlation shown by Laura F and her ALICF team is interesting. At least we have moved from Zero and One as the Limit of Co-relation!!

    Correlation above Unity for Strong Forces Interaction going up to 6 is Extremely Interesting.It also explians the relationship between Strong Forces and Weak Forces like Va Der Waals Force and Surface Tension whose corelation is probably at the low end of the Zero to One Scale. It will also explain the Force of Gravity. We are only dealing with the Forces of Attraction. This is at the Gross level. I wonder why the Theory is not extended to Negative Corelations. Measure that as well.

    I will bet that such similar Strong and Weak Forces also exist at the sub- atomic levels. The Cyclotron Experiments and the discovery of these sub atomic particles since they started, could be an indicator of the binding strength of the same holding the matter together at the Gross World level.

    The Binding Stregth of all such sub-atomic patticles should be determined and the collisions between the same and others with mass and without mass can lead us to the desired Cold Fusion we may need to travel to the stars!

    This successful attempt to measure the correlation between Mass- Space – Latice interactions for strong forces is only a first step as it is done with low speed and low momentum quark and with mass . Do it for others with or without mass and the wave behaviour. I wonder of there are hybrid Wave-Particle entities among the sub-atomic entities! AND What kind of Behavior they exhibit. Critical Experiment to Shed Light on LIGHT! By the way degree of Corelation determines Certainty/Uncertainty. Once we get this sorted out we can move from “Bhors Uncertainty Principle ” to the Scientists name who proves this “Certainty Princile”. Bet you it will be a AI program!

    You may be wondering — Why did I say We may need to rethink the ” Theory of Every Thing”. Thing represents MASS . I suspect we will Need to Undertsand the ” Theory of Every Energy”. The venn Diagram of the “Theory of every Thing” and the ” Theory of Every Energy” is the intersectionof the two which is the fulcrum on which our current state of Knowledge exists. We need to workk out the mathematics of Higher Dimensions.

    All current Knowledge of Quantum we have obtained rests, for the two dimensional / Three dimensional world we inhabit. .

    ALL of this does not give us any clue about how Life came into Existence. Also does not explian wy different Life Forms have different Life Spans. Have always wondered why when we go to places of worship like temples , churches, synagogues and Mosques after the prayers are over the Priest gives us holy water and also Prasad . Similarly in the Catholic Church the Prayers are Called attending MASS as also ALL other faiths!

    Maybe the knowledge of the equivalence of MASS and Energy equivalence is lost and this research will give us results which will help us to travel to distan stars at unimaginable speeds! Let us hope the Results prove that these Priests were Right after All!!

    Mad Hatter Signing Off ALICE . ALL the BEST to YOU.

    Opinions Expressed are Personal and not binding on Anyone incuding Artificial Intelligence Programs which can now Solve Schrodingers Equation. Maybe AI can explain how the Same Cat can be both inside the room and outside the room!

  7. Sekar Vedaraman | February 14, 2021 at 4:10 pm | Reply

    Valentines Day Gift from the Mad Hatter!

    Thanks ALICE for helping me Connect the Dots!

  8. Sekar Vedaraman | February 14, 2021 at 4:22 pm | Reply

    One Final Thhught on this exciting discovery.

    Why limit the searh of the Universe to only Neutron Stars. The Evidence of the same is /will be Probably visibile with Future Advanced Telescopes including the use of Telescopes of the Creator. Both need to be refined ……

    In the Footprints of Time we can see the tracks left by the creator. Fascinating Research lies ahead and Collaboration is the Key. Astronomers are the Pioneers who spot such Phenomenon!

  9. Sekar Vedaraman | February 14, 2021 at 8:53 pm | Reply

    One More Thought I am sharing after some more Tinking.

    Fact 1: The numerous Galaxies in the Milky way appear to be fleeing away fom ours rapidly.Self Preservation mechnism? Maybe?

    Fact 2: There is Huge amount of Dark Matter at the Centre of the Galaxy.

    Hypothesis: We may be in the Expansion pahse of the Universe where the Force of Repulsion is driving away the Other Galaxies and the Univesre is expanding. We don’t think that the expansion phase can go on forever. We don’t know about the elsticity of this expnasion and the forces driving the expansion. Countless stars in various stages of birth , life and death. Creating dark matter as time passes. If 86% of the Univesrse is a unknown quantity ” which we call “Dark Matter” we need to find out more. Some may be Real ” Dark Matter ” as a collapse of the Star which has become a singularity. Others may be in the Thores of being Born from the mating of Galaxies!

    The complexity boggles the puny mind. Maybe Artificial Intelligence will give us some answers. I doubt if human Intelligence by itself can. However a networked parralel processing of human intelligence could get to the solution rapidly and easily.

    Fits in with the ancient Hindu Philosophy of” Hiranyagarbha”.

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