Why Particle Physics?

April 3, 2010 at 8:04 am 18 comments

I have blogged less since Tuesday because I have been working with journalists at Northwestern to write articles and interviews on the start-up of the 7 TeV run of the LHC. This has been a very satisfying experience, since all three ladies and a young man are intelligent, attentive and enthusiastic about this momentous event and the participation of scientists from Northwestern.

We were featured on the front page of the Daily Northwestern in an article “Northwestern physicists collider particles, create history” by undergraduate journalist Ali Elkin, and on the front page of the Northwestern University web site in an article “Another Big Bang” by Megan Fellman with a slide show prepared by Matt Paolelli. Later this month, a research newsletter will include an article being prepared by Amanda Morris. And there is a short blurb about us on the departmental web site.

The most delicate question journalists ask is: What do you hope to accomplish/learn from all this?. They were sincere and took my response seriously and avoided hackneyed phrases about the origins of the universe and the dreaded awful phrase about the Higgs boson coined by Leon Lederman.

At the same time, many comments posted in response to Dennis Overbye’s article in the New York Times are highly critical of our endeavor to learn more about particle physics – why didn’t we work on a cure for cancer instead?

Indeed – we have a bad situation here, because some scientists and journalists make exaggerated, overblown, stupendous claims (“LHC physicists hope to understand the origins of the universe!”) while some segments of the general population see science as essentially utilitarian (“Go find a better source of energy and solve the problem of global climate change!”).

Why do we do particle physics – for a career? The answer from each of us has to be personal, so I can only explain my own motivations. As a teenager, I was often entertained by physics articles in Scientific American, which spurred me to read low-level science books. I loved to learn about the fundamental forces and particles of nature, and the role of symmetry and order in explaining (better said, describing) them pleased my sense of intellectual beauty. Eventually I followed my interests and earned a Ph.D. in experimental particle physics and recognized that the best research opportunities for me were to be found at LEP. Later, I worked on CDF and now I am very busy with CMS. While I admire the imagination, deep thinking and fruitfulness of my theoretical colleagues, I am convinced that insights into particle physics beyond the standard model will come from experiments in the coming years, and I want to be a part of that.

As everyone reading this blog knows, the standard model is technically successful, but deficient as an ultimate explanation for the fundamental forces, particles and symmetries of nature. I do want to see what comes after the standard model, some time in my lifetime. Is there really a symmetry connecting fermions and bosons? Are there really extra dimensions of space, and if so, are they small or large or warped? Will we finally get the clue we need for the riddle of the quark and neutrino flavor matrices? Is the Higgs sector mundane or exotic beyond our wildest imagination? Finally, can particle physics – the LHC – provide crucial information for the elucidation of dark matter? For me, answers to those questions would be immensely satisfying. I do not need to explain the origins of the universe in order to feel this enterprise is a success.

Why does society need the answers to these questions? Maybe there will be technological spin-offs from the LHC and other experiments that will benefit society. But for me, the questions we ask, like the questions asked by many physicists and astronomers not involved in particle physics, are justified as an expression of human’s innate philosophical nature. Civilization is not just the technological betterment of the physical state of human beings. It is also the enhancement of intrinsic, and noble, human characteristics, such as an appreciation for beauty in the arts, for triumph in sports and athletics, and for higher ethical and moral standards in the justice system. Perceiving scientific truths about nature belongs with these things, not with traffic and pollution control. Why is our research in particle physics justified and good for society? For the same reason that people dance the samba, or learn to make boeuf bourguignon, or visit the Art Institute. It appeals to the better side of our nature and ennobles our civilization.

Anyway, that’s my view, for the record. I’m not saying anything new or surprising here, and many of you would say it better. And you should.


Entry filed under: Outreach, Particle Physics.

CMS Muons in 7 TeV Collisions Where have I been?

18 Comments Add your own

  • 1. Teresa  |  April 6, 2010 at 12:12 am

    Why particle physics? Money, prestige, job security. The usual reasons…

    • 2. Andrea Giammanco  |  April 11, 2010 at 4:24 am

      Hi Teresa, by choosing particle physics (or in general the academic world) one chooses job INsecurity, and about money, well, the salary level depends a lot on the country (*) but a general rule is that it tends to be significantly less than for an equally qualified job in industry.

      (*) and even the ratio of the salary to the local cost of life.

      Maybe prestige, yes, or ego, can play a role. But I invite you to consider the possibility that there could be also other reasons in alternative or in addition to that (like actually liking this job so much to prefer to do an objectively miserable life from the point of view of job insecurity and of the starvation of time available for a private life, and nevertheless be of good humour when, let’s say, a W->e+nu candidate shows up in the event display…)

      • 3. Clive Tooth  |  April 11, 2010 at 7:42 am

        Andrea… I think Teresa had her tongue firmly in her cheek… 🙂

  • 4. cormac  |  April 6, 2010 at 2:15 pm

    Interesting article but
    1. Why do most physicists object so strongly to the name ‘God particle’? Given that the Higgs field and associated particle is thought to determine the masses of other particles in the SM, it seems quite an apt name to me i.e. gets the message across that it is a very important particle
    2. “LHC physicists hope to understand the origins of the universe”
    should of course read “hope their experiments will help understand the origins of the universe” but again, it’s not that far off, is it? It seems to me to get the basic idaa across

    • 5. Clive Tooth  |  April 7, 2010 at 2:58 am

      Ranking elementary particles by importance seems silly. Is the electron more important than the up quark?

    • 6. Arthur Sabintsev  |  April 7, 2010 at 7:50 am

      1) Mass is not the only degree of freedom available to particles. There is also spin and charge and a slew of other properties (via quantum numbers) such as isospin, hyperon charge, Baryon number etc… Sure, the Higgs is important, but it is in no way deserving of such an ostentatious name.

      2) They’re experiments, regardless if they succeed or fail will allow them to better understand the universe. If they fail, then they know what theories or theoretical frameworks are wrong, and can throw those out. A big problem will occur if ALL of the theories are wrong. Then it’s back to the drawing board.

  • 7. carlbrannen  |  April 6, 2010 at 3:31 pm

    There’s this movie, “The Truman Show” about this guy who thinks he’s living a normal life, but actually everything is a set.

    Amazingly, he never notices that the moon is always in quarter phase, and is incorrectly placed relative to the sun. But eventually he figures out what’s going on.

    To me, that’s why we study particle physics. As you heat something up, it gets supposed to get simpler and simpler. It starts out as a solid, then liquid, gas, atoms, nuclei, quarks. What comes next? That’s why we study particle physics.

  • 8. Zoe Louise Matthews  |  April 8, 2010 at 5:10 am

    I studied particle physics because I wanted to understand some of the mysteries of the universe. Some of those mysteries have been solved and the story is fascinating (neutrinos, parity violation…) Some are still outstanding and a curious as ever. We know roughly where to look but we don’t know what answer we are going to get to any of the questions.

    The ALICE experiment, for example, really IS trying to understand the beginnings of the universe – the very first microseconds after the big bang – and the way it evolved and cooled into nuclei. We do that by recreating the temperatures on a very very small and much shorter timescale and measuring the mess as accurately as possible. It sounds like an overblown statement but it isn’t.

    But that’s why it’s important for scientists and journalists to talk to each other, because too easily that turns into “big bang machine” and we are back to sensationalist nonsense again.

    Great blog! 🙂

  • […] Why Particle Physics? « Collider Blog […]

  • 10. RSTX45851  |  April 30, 2010 at 11:01 pm

    Gravity and the universe


    Let’s see if we can figure out where is all started
    Before there was matter in the universe and all it consisted of was an empty vacuum.
    How did it become filled with matter? Stars, planets, gasses etc.
    Many have a theory that it all started from a single point in time and space and expanded from a “BIG BANG” I on the other hand see thing differently.
    This does not explain where anything came from and is more of a fairytale, like saying where did your presents come from and your parents tell you “Santa Claus” and until you turn 6 or 7 you believe it.

    So let’s try another theory, let us imagine the universe was void of any matter being a vacuum of space, and matter which is nothing more than energy in another form came from another universe within another dimension.
    As one of these dimensions rupture it merges into this dimension and energy is forced into our universe.
    Imagine a universe filled with energy that is rupturing out into another dimension because it has reached its limit of space so is forced into another dimension, which is what is happening in this dimension,
    Every galaxy has what they call a black hole; some have more than one according to recent discoveries, these are not caused by imploding stars but are actually where the energy ruptures into this universe from the other universe within another dimension.

    As the energy is injected into our universe it is entering into a dimension that is stable with its own form of energy, we will call this (dark energy) Dark energy is a force so strong it transformed the pure energy by compressing it into matter, as an example you all know what happens when this matter is released, you see this in the atomic bomb, when the dark energy that holds atoms together is compromised this pure energy is released which is what you see when these bombs explode.

    If dark matter were to become weakened matter would become unstable and life would not be able to form, your body would literally transform with atoms being unstable and some may release/ transform into energy causing a flash that burns everything around it etc.

    An example of how this could happen is when the universe stops expanding and the dark matter is done decompressing to the point it no longer hold atoms together, that is of the universe expands enough, there is also the opposite reaction which is explain more later in this post.

    The reason gravity is so strong in black holes is due to the compression of dark matter, to better understand how this works imagine what happens when a bomb explodes under water, everything in the area is compressed by the concussion, the oxygen in your lungs would be forced out and your bones would be crushed from this concussion.
    A black hole is compressed dark matter caused from the cataclysmic event of the pure energy rupturing into this dimension leaving behind black holes, these may last for billions and billions of years but will mend by filling the ruptured universe with matter that surrounds it while the dark matter decompresses.

    As matter is being compressed by the dark matter, energy transforms into gases then into particles forming matter, the stars and planets you see are pure energy transformed by the dark matter, remember all things in the universe are made of atoms, atoms are compressed energy being held together by dark matter, dark matter is not black but is invisible we just use the term dark matter to explain gravity, the gravity you feel on earth is from the compressed dark matter around the planet, the larger the planet the greater the gravity, this is because there is more matter being forced into this space, if you were on the moon the gravity would be much weaker because the moon is smaller therefore displacing less dark matter.
    As energy enters the universe is displaced dark matter compressing the entire universe more and more.
    Energy is still entering the universe today and as it does space will speed up, then dark matter will equalize spreading galaxies apart while it equalizes.
    The more energy that enters the universe the greater gravity will become once the universe has expanded to its limits, until then the universe will continue to speed up and slow down its expansion.
    Here is one for you to think about: when the universe reaches its capacity of expansion and energy continues to enter into the universe, gravity will increase its force upon matter making it impossible for life to form under such pressures, it may get to the point that this universe will also rupture into another dimension and the process begins again.
    There is much more I could explain and hope to get time to post more of these helping the human race get a better understanding of how the universe was formed.


  • 11. Bewildered  |  May 11, 2010 at 5:17 pm

    I completely agree that this is why we study particle physics and why it matters for society. I’d add though that technological applications appear not just as spin offs, but also as a direct consequence of of fundamental research. If we don’t increase our understanding of how nature works we run out of ideas of how to build practical applications. In some sense the two motivations are fundamentally related.

  • 12. Fred Howard  |  October 10, 2010 at 9:28 pm

    Your long posting and comment 11 have it right. Excellent! It seems to me useless to go on and on about Big Bangs and ultimately original causes until we have a much better understanding of what is going on around us between particles, our solar system, and the distant galaxies with their supernovae shedding photons and neutrinos upon us. Truly the firmest grasp we have of that range of preliminary insights we have today lies in the Particle Data Group’s accumulation of hard empirical data over many decades of effort by thousands of gifted investigators, who were aided by the brilliant sequences of probable estimates of what could be hidden in the black boxes of our atoms that we call quantum mechanics. Let us return to the hard data, get more of it, and ponder over more of it.

    I have been working on the particles following an insight from the Particle Data Group Summary Tables several years ago now. A very concise equation I uncovered there led directly (published 2005) to exact mass/charge values for the common quarks within and very close to the error limits now published (2010) by QM theoreticians to great acclaim. My son, a Georgia Tech mathematical physicist, thought I should start blogging to find others with common interests in the particles, including the neutrinos too, in fact all the particles, as the papers on my website will show (electron-particlephysics.org) In summary, the same equation’s results found values for the common and uncommon quarks that accounted exactly under the equation for the baseline hadron values so enthusiastically welcomed when published three years later by others (2008), as well as at least four more originally in 2005-6, and in the meantime for all of the PDG Summary Table baryon series and all of the PDG Light Unflavored Mesons in their stair-step progressions of what I call Group Leaders and Isomers. To round it off neatly, the balanced structure of the proton from these distinctive common quark components explains that baryon’s amazingly stable empirical half-life as well as the lone neutron’s instability until it is precisely rebalanced (to our universe’s causation) by bonding forcefully with a proton in the deuteron structure that underlies the cyclic peak abundances of the more stable nuclei. The other main outcome is the necessity for numerous exactly defined (and doubtless oscillatory) neutrinos in both the pre-2004 PDG ranges of mass limits and the cosmologists”s micromasses to account for the present electrically unbalanced, and therefore unconserved, charges that now have to pop in and out of the vacuum (preserving constant net charges only) in every major baryon decay (of over 30% fractional mode channels) except the one that only releases a photon rather than other massive particles. I’m looking for someone who might like to discuss this series of consequences of one empirical equation. [There is also (necessarily) the demonstration of the only possible form of microquantal constituent that could contribute to each particle its share (under the mass’charge equation) of the four previously sourceless forces from structures that inherenlly spin in orbital linkages, with the scaling equations whose solutions show why the atomic electron and the collider’s electron have such drasticly different and elastic dimensions. (In this, and in entanglements, the baseline art of the early 1900s, as carried forward, appears to have been on the right track in large part, but also slightly misleading at a critical juncture.) ]

  • 13. Fred Howard  |  October 10, 2010 at 10:12 pm

    On re-reading too late to stop the comment, I should have given the potent little equation its proper title of a mass/charge power law in the structural step of composing particles out of two mirror-image microquanta of plus and minus charged mass. In the next steps to hadrons and to larger nuclei such as the proton and above, the exponent does vary, and there the law goes exponential. Also all quarks are charged, so the charge coefficient factor taking care of neutral pairs of charged microquanta in the more fundamental structural step then vanishes in the exponential steps, shortening the equation by half as the structures become larger and exponentially more massive.

  • 14. Patrick  |  November 7, 2010 at 11:29 pm

    Why should we continue on smashing particles?

    For physicists, this is the equivalent of seeing. We weren’t given by evolution the ability to sense the strong or weak force, so we need to grope with our eyes, hands, ears and minds into the numbers and traces left by the escaping particles to know anything at all about those forces. Everything we know has come from these kind of interactions. To stop is to turn off the light and leave us thinking in the darkness of the cave again.

    I teach HS physics at times and I have been thinking over the last 24 hours about re-conceptualizing the way I think about force, energy and interactions I will add some of those thoughts as another response. I would appreciate any corrections and responses from this intelligent and interested readership. [I understand they are a little beyond where most high schoolers start.]

  • 15. Patrick  |  November 7, 2010 at 11:45 pm

    After years of learning about energy and forces and interactions, I think I finally am gaining some insights as to the meanings of these very basic concepts.

    We live in a universe that is at a very precise ambient temperature that has allowed some of the properties of particles that are witnessed today by sentient creatures to be more obvious than others.

    One of those particles that we can notice at this energy level we call the electron and the forces between its participants we call E-M force. Actually the force that we most witness is electric force, but quite separately it is accompanied by a “magnetic force” which seems to be the result of a momentum change that doesn’t give rise to a photon in any unique way. That is, we cannot distinguish between the delta p (change in momentum)—which is the only thing that releases an energy wave to our eyes [or ears or tongue or nose]—of an electron in up spin or down spin. Luckily we can distinguish the force they exert as an amalgam (the domain of a magnet) on the field in question. So though we cannot see the difference, we can feel the difference; and at least to most physicists that is enough.

    Our primary sense is sight, and as such, we are best able to distinguish between things by sight. So we rely on photons to give us most of our information. Such boson-mediated information begs the question of what a boson is. A photon [and by extension, any boson] is the wave that is the net result of a change of momentum from a higher energy electron [usually] to a lower state.

    Why should any particle give off energy? Because every particle is optimizing at all times by definition its position in the universe, relative to all other particles. Space is the freedom of movement [dimensions are the degree of freedom] of the particles we experience. In all likelihood, there are many more dimensions than we are able to experience, both because the energy levels at this point in the universe’s development. Earlier in the universe, there was enough energy to allow for many more degrees of movement of very energetic particles. Electrons (and protons) are restricted to a fairly narrow average range of energies.

    Also because we are fragile creatures, there is a very limited range of energies available to our sensorium. No less energy than the equivalent of a single photon of red light, and no more than the thud of a ground wave from an earthquake hitting our balance sensors. Sure one is 10 billion times more energetic than the other [approx] but in the scheme of things, it is a paucity of data. The range of energies that we can “experience” enough to learn from [as cognitive beings using our senses from birth], we are stuck in a much smaller range: ~ 10^3.

    E-M energy is this net-momentum-change-wave. It can either be sucked in or expelled in an electrons interaction with other electrons. And sometimes the energy is turned instead into KE of the whole atom. As such, it is very hard for an individual electron to again gain the net effect and increase its singular momentum–one explanation of the third law of thermo. [Rare interactions give such a result. But they are rare enough to be considered quantum anomalies.]

    As a wave front the energy wave is being dissipated quite rapidly in 3-D space. But if it encounters another particle in the right state to undergo a change of state, if that particle is pushed over some favorable edge, then the second particle absorbs the energy, and the 3-D wave in essence stops.

    That is as far as I got in an hours thinking. Tell me what you think.

  • 16. kelvin  |  December 11, 2010 at 7:43 pm

    excuse me,may i ask a qq? can a positron annihilate a proton,and can an electron annihilate an antiproton??

  • 17. David Brown  |  January 17, 2011 at 12:27 pm

    If particle physics can make quantum theory easier to understand, then that might be a worthwhile return on investment. The mathematical and computational spin-offs probably justify fairly expensive R&D efforts in particle physics.

  • 18. northwestern college  |  September 18, 2012 at 3:01 am

    The future of this studies has a very good scope indeed . so as a passion in the studies i would like to have a look into it


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