Have we reached the end of Particle Physics?

“The particle and the planet are subject to the same laws and what is learned of one will be known of the other.” -James Smithson

The entirety of the known Universe — from the smallest constituents of the atoms to the largest superclusters of galaxies — have more in common than you might think.

Image credit: Rogelio Bernal Andreo of http://blog.deepskycolors.com/about.html.

Although the scales differ by some 50 orders of magnitude, the laws that govern the grandest scales of the cosmos are the very same laws that govern the tiniest particles and their interactions with one another on the smallest known scales.

Image credit: R. Nave of http://hyperphysics.phy-astr.gsu.edu/hbase/particles/expar.html.

We study these two scales in entirely different ways; the largest scales can only be studied with great telescopes, using the natural cosmic laboratory of outer space, while the smallest scales require the largest, most powerful machines ever constructed here on Earth: particle accelerators! And of all the particle accelerators ever built by humanity, the Large Hadron Collider (LHC) is by far the most powerful.

Image credit: Maximilien Brice, © CERN.

Although many of us are still hoping that the LHC finds something new, exciting and unexpected, it was constructed — first and foremost — to find the last missing piece of the Standard Model: the Higgs Boson. There are many types of fundamental particles in the Universe, but we can divide them into three general categories: fermions (like quarks and electrons), gauge bosons (like the photon), and the Higgs, a unique, fundamental scalar particle.

Image retrieved from Fermilab, modified by me.

I don’t know whether you followed physics news prior to the LHC, but if you did, you’ll remember that there was wild speculation about what mass the Higgs Boson was going to have. There’s a very good reason for this: all these particles — through the physics of quantum field theory — have dramatic effects on what we observe in this world.

Image credit: DESY in Hamburg, from http://www.desy.de/f/hera/engl/chap1.html.

For example, we normally think of protons and neutrons as being made up of 3 quarks apiece, but those three quarks only account for some 2% of the total mass of those particles; the rest of that mass comes from all the other particles, interacting via the laws of quantum field theory (QFT). All these particles are so interdependent on one another that if the top quark — the heaviest of all standard model particles (and some 180 times the mass of the proton) — were twice the mass it actually is, every proton in the Universe would be 20% heavier than the protons that actually exist!

So, too, the mass of the Higgs would be highly dependent on what else is in the Universe, and what interactions actually happen according to the laws of QFT.

Image credit: David Kaplan.

The standard model, of course, does not include gravity. But the real Universe has gravity, and we assume that whatever the full, fundamental theory of the Universe is, it incorporates all of the known forces, gravity included. When it comes to gravity, we typically consider General Relativity as a low-energy, large-scale (compared to the Planck length, at least) approximation of a more fundamental, fully quantum treatment of gravity, which is simply beyond the scope of our theoretical tools.

Image credit: Jim Mims of Science And Computer Science, from http://www.alpcentauri.info/.

At least, it has been for generations. But there is a new idea gaining traction in recent years when it comes to making a quantum theory of gravity: asymptotic safety. Without going into any mathematical detail (and with full disclosure that I myself don’t understand it as well as I’d like), you can think of it as a mathematical trick that allows you to incorporate gravitation into your QFT. (For a little more detail, see here, and for a lot more, see the Weinberg original.)

There’s a very important reason we care about this: if we understand how to incorporate gravity into our quantum field theories, and we’ve measured the masses of all the standard model particles except one, we can theoretically predict what the mass of that one remaining particle needs to be in order for physics to work properly at all energies!

Image credit: Harrison Prosper at Florida State University.

We can do this because demanding that the Universe be stable constrains that last free parameter — the mass of the Higgs boson — to be one particular value. If the mass turns out to be that value, then that’s indicative that, if asymptotic safety is a valid idea, there are no new particles in the Universe that couple to the Standard Model. In other words, there are no new particles to be found by building colliders in the Universe, all the way up to Planck energies, some 15 orders of magnitude more energetic than those probed by the LHC.

But if we can predict that mass, and the actual mass of the Higgs boson turns out to be anything else, either higher or lower, then that means there must be something new in the Universe in order for physics to be self-consistent. Now, here’s the truly amazing thing: that mass was calculated back in 2009, before the LHC was turned on.

Image credit: From Phys. Lett. B's paper by Mikhail Shaposhnikov & Christof Wetterich.

You can read the abstract here and the full article here, but what’s truly amazing is that we’ve now found the Higgs, and we know its mass. Want to see what this paper, nearly 3 years old now, predicted for the mass of the Higgs? (Highlights, below, are mine.)

Image credit: Mikhail Shaposhnikov & Christof Wetterich.

Holy. Crap.

So I want you to understand this correctly, because this could be huge. If asymptotic safety is right, and the work done in this paper is right, then an observation of a Higgs Boson with a mass of 126 GeV, with a very small uncertainty (±1 or 2 GeV), would be damning evidence against supersymmetry, extra dimensions, technicolor, or any other theory that incorporates any new particles that could be found by any accelerator that could be built within our Solar System.

Fast-forward to this past July, when the discovery of the Higgs Boson — confirmed to be a single, fundamental scalar particle of spin-0 — was announced. What was its mass, again?

Image credit: Vixra blog, of combined CMS/ATLAS Higgs signal.

According to the combined ATLAS+CMS data (both major detectors), a Higgs of mass somewhere between 125 and 126 GeV was detected with a (robust) significance of 6-σ, with an uncertainty of around ±1 GeV. In other words, those of you who followed the excitement in July may have witnessed the last fundamental particle physics discovery we will ever make. There still may be more out there, but the Higgs Boson could have very well been the last unfound fundamental particle accessible to colliders.

Yes, there are still more questions to answer, more physics to learn and more to explore even with the LHC, including questions about dark matter, the origin of neutrino mass, and the lack of strong CP-violation. But there might not be anything more to learn — at least, in terms of fundamental, new particles — from doing particle physics at higher and higher energies.

Comments

  1. #1 Cosmonut
    October 17, 2012

    Fantastic. !!
    This is the first true prediction of the Higgs mass I’ve seen.
    Unlike the more recent fiasco by string theorists “predicting” the mass soon after the first set of LHC results was announced !

    Am waiting to see if the particle physicists like Matt Strassler start talking about this…

  2. #2 mithril
    October 17, 2012

    regarding quantum theories of gravity.. where does the current evidence point regarding the “gravity as a particle” view? are we likely to see ‘gravitons’ show up as a real thing, or is one of the non-particle explanations gaining traction?

  3. #3 Cosmonut
    October 18, 2012

    Also, if I understand this right, it means that dark matter interacts with ordinary matter ONLY through gravity and no other force.
    In fact, there could be whole classes of particles like our SM particles mutually decoupled from each other except by gravity.

    Of does the paper mean that the SM particles are the only constituents of matter ? If so, how do they account for dark matter.

  4. #4 Wow
    October 18, 2012

    As best as I can read it, mithril, asymptotic safety is fairly much saying that the closer you get to the particle of gravity, the less it is there because of the virtual particles interfering with its effect on other masses.

    A bit like how the electron charge is slightly hidden by the presence of virtual particles (though there were last I knew many people against this idea except as a fig-leaf) with opposite charge so that the electron has a fraction of these charges removed when you look from sufficient distance.

    Being a point particle with no extent, the charge of the electron asymptotically approaches the “bare charge”.

    Though my destription of this theory is probably no better than that which allows you to work out which way to hold the damn thing..!

  5. #5 Loren Amacher
    October 18, 2012

    This terminology-challenged (due to age!) person would appreciate if someone would explain just what ‘asymptotic safety’ means. I do try to understand!

  6. #6 chelle
    Latveria
    October 18, 2012

    “Have we reached the end of Particle Physics?

    Great idea! Now is a good time to end it, because:

    “Do nothing, and nuclear testing will eventually come to an end.”
    http://tinyurl.com/Nuclear-Testing-Greenpeace
    (the image is from the ending of the Planet of the Apes :mrgreen: )

  7. #7 Cliff
    Connecticut
    October 18, 2012

    Asymptotic safety is interesting, but it doesn’t seem plausible as a quantum theory of gravity that could actually describe nature. AS basically addresses ONE of the hurdles of describing gravity quantum mechanically: the nonrenormalizability. But There are other issues that must be addressed, like correctly accounting for the entropy of black holes, and there AS seems practically guaranteed to give the wrong answer. There are all kinds of other consistency criteria to consider and no way to satisfactorily address them with AS. There is still only one good choice to do the job and that is strings. Certainly if anything else comes along that could address all the requisite issues, I would like to know, but it doesn’t seem plausible at the moment.

    Of course some people will still take offense at their inability to personally test Planck-scale physics (take it up with God), but Im confident we will learn plenty from experiments to get a much better idea of what is going on.

  8. #8 Jeremy Henty
    October 18, 2012

    Isn’t this scenario contradicted by the existence of dark matter? Dark matter is not part of the Standard Model, yet it does interact (albeit weakly) with the particles of the Standard Model. So how can we account for dark matter if asymptotic safety is true?

  9. #9 Sinisa Lazarek
    October 18, 2012

    Have to say that am a bit puzzled by the title. As far as I know, there is nothing in the Standard Model that prohibits i.e. quarks to be made of yet smaller particles. It is true that we “assume” them to be non-composite, but it hasn’t been experimentaly proven.

    There could be much more surprises out there. Long way to go from 10^-16 to 10^-34.

    As for gravity. Am positive that it will get quantized somehow in the future, since everything that “creates” gravity is quantized already in QM. It’s an existing field.

    So, really don’t think we have reached the end of Particle Physics. To get philosophical, don’t think there is even an end.

  10. #10 Donovan
    October 18, 2012

    Didn’t Chaplain’s Assistant Billy Pilgrim predict this with much more accuracy?

  11. #11 Alan L.
    October 19, 2012

    @Ethan (quoting from the post):
    In other words, those of you who followed the excitement in July may have witnessed the last fundamental particle physics discovery we will ever make. There still may be more out there, but the Higgs Boson could have very well been the last unfound fundamental particle accessible to colliders.

    Isn’t it a bit adventurous and premature to be making such a claim?

    Surely you’re not suggesting that CoGeNT and DAMA have seen nothing scientifically acceptable in the way of possible Invisible Dark Matter particles?

    A DM particle with about the mass equivalent, it seems, of about two protons, or thereabouts. That’s easily accessible to the LHC. Hell, it was easily accessible to the Bevatron in 1956.

    And whatever happened to the Dirac-Cabrera Magnetic Monopole in the larger scheme of the Standard Model? Can it really be written off in the style of a Goldman-Sachs style piece of creative accounting?

  12. #12 Tom
    October 19, 2012

    Read the work by Hotson and his new understanding of Dirac’s equatiion. No big bang, none of this Higgs malarkey. He explains all the forces, and how they work on the micro and macro scale. Amazing work. This whole idea of many particles making a few is silly.

  13. #13 Aquanerd
    October 19, 2012

    “Have to say that am a bit puzzled by the title. As far as I know, there is nothing in the Standard Model that prohibits i.e. quarks to be made of yet smaller particles. It is true that we “assume” them to be non-composite, but it hasn’t been experimentaly proven.”

    I have to agree with Sinisa here… what about these theoretical preons?

  14. #14 Wow
    October 19, 2012

    “So how can we account for dark matter if asymptotic safety is true?”

    You answered your own question:

    “Dark matter is not part of the Standard Model”

  15. #15 Zephir
    Prague
    October 19, 2012

    This is just an accident. There was another one [hundred of articles](http://arxiv.org/abs/0708.3344), predicting the Higgs boson mass in less or more close interval too…

    In particular, I do expect a hints of higher particle generations and the Higgs boson itself will be probably recognized as [whole cluster of particles](http://www.aetherwavetheory.info/images/physics/aether/cmbr_higgs.gif) (*AWT prediction*)

  16. #16 Bob
    October 19, 2012

    It is now known that this asymptotic safety model *does not work*, the reason is that the paper assumed a top mass of 171 GeV. But we now know the top mass is about 173 GeV. So if you look at eq.(12) in that paper, it predicts m_Higgs = 130 GeV, about 4 or 5 GeV too much, hence ruled out.

    Instead, one needs new physics at sub-Planckian scales. A nice recent example which appears to work (as far as I can tell) is http://arxiv.org/abs/1210.3624 . It simultaneously solves the strong-CP problem and correctly relates the dark matter abundance to the Higgs mass. I wonder if it might be correct? who knows…

  17. #17 William McDill
    California
    October 19, 2012

    Einstein determined that gravity was an illusion derived from the path taken by mass through curved space. There are no gravitons, gravity is not a force but an effect from the space-time field.

  18. #18 CB
    October 19, 2012

    @ Tom “This whole idea of many particles making a few is silly.”

    What are you talking about? Before the Standard Model came along with it’s simple table of quarks, bosons, and leptons, there were literally HUNDREDS of particles known to exist. Still are, of course, but we can now understand them via simpler parts. It is a few creating many.

    Of course the objection to it being the other way around is merely aesthetic; if it turned out the universe really had hundreds of fundamental particles, that would just be the way it is. But that’s not the way it appears to be today, and neither is your statement of “many particles making a few”.

    P.S. Hoston’s work also supposedly explains psychic phenomenon. Quite a “Theory of Everything” there.

  19. #19 OKThen
    Hear no evil, see no evil, speak no evil
    October 19, 2012

    Well I’ve read it and I certainly don’t understand it.
    I’ll keep trying.

    Here are a few quotes from those who understand.
    “As usual with quantum gravity, asymptotic safety will only manifest itself at the Planck scale. If the world is four dimensional there is at present little hope of observing directly the consequences of the asymptotically safe behaviour in the laboratory. However, in theories with higher dimensions the Planck scale could be at the TeV scale. Then, signals of asymptotic safety could be observed at colliders.”

    “Since asymptotic safety is concerned with the ultraviolet behaviour of the theory, its impact in cosmology will probably be most important at the very earliest stages of cosmic history, e.g. the inflationary era. ”

    “This means that while in QED the quantum fluctuations screen external charges, in quantum gravity they have an antiscreening effect on external test masses. This entails Newton’s constant becoming a scale dependent quantity G(k) which is small at small dis- tances l ≡ k−1, and which becomes large at larger distances. ”

    The above quotes come from papers from this asymptotic safety site http://www.percacci.it/roberto/physics/as/index.html

    Truthfully I con’t understand anything else.
    And I’m not even sure I understand anything.
    I have at least 100 questions that just serve to show how little I understand. So I won’t ask any.

    Ethan, thanks for pointing this important topic out to us.
    Please cop me back to it as you understand more.
    Tough stuff.

    Steven Weinberg talk The Quantum Theory of Fields: Effective or Fundamental?
    http://cdsweb.cern.ch/record/1188567
    This talk is 73 minutes long and understandable and comes up in my search for asymptotic safety, so I’m listening to it. Nothing else promised. He is very understandable, nice. I’m at 10 minutes but will have to continue listening later. Nice education his giving at CERN 2009

  20. #20 Bob
    October 19, 2012

    The asymptotic safety argument is in contradiction with all known facts about gravity. I wouldn’t bet on it…

  21. #21 Wow
    October 20, 2012

    And it seems my original reading wasn’t correct.

    Bugger.

    It’s not nice for your self esteem to have friends smarter than you on something…

  22. #22 Amrit Sorli
    Slovenia
    October 20, 2012

    Mass of the Higgs boson and mass of the all other particles has origin in diminished energy density of quantum vacuum.
    In empty space energy density of quantum vacuum is: (mp x c2) / Vp.
    In the presence of a given elementary particle energy density of quantum vacuum is: (mp x c2 – hv) / Vp.

  23. #23 Andrew P
    October 20, 2012

    Saying there is nothing more to be found in particle physics is like saying in the 1890s that nothing remains to be invented. We all know how that prediction turned out. The fact that dark matter has 5x the mass of standard model matter makes me very skeptical of such claims.

  24. #24 Wow
    October 20, 2012

    Only in so far that they both talk about “nothing more to discover”.

    What if there are only a limited number of elementary particles and force carriers? At some point through discovering more and more you’d actually find that there really isn’t any more to discover.

  25. #25 chelle
    October 20, 2012

    Andrew P,

    “Saying there is nothing more to be found in particle physics is like saying in the 1890s that nothing remains to be invented.

    Haha. You need a giant machine like the LHC that uses as much energy as a whole city to generate a bunch of particles that are of absolutely no practical use, and certainly not containable. In contrast to electricity and magnetism that was already a know thing for millennia, and easy to generate. btw The Standard Model is already 40 years old and except the long awaited Higgs Boson nothing spectacular has been found for the last 25 years, and we already get all these kinds of ‘new’ particles out of cosmic ray collisions, … they are showering in the billions down upon us, and there is nothing we can do with them. Physically we have reached the limit of what is physically measurable.

    What are you actually hoping to find; some sort of energy source that can be used as fuel for space ships to fly faster than light, or a secret doorway passage to an other universe, or pink bunny that can cure any disease.

    Some realism is needed, the only thing that is possibly left to discover is that we ignite some combustion process, because of the intense heat that is focused in one particular spot, during these collisions. Curiosity isn’t always harmless, and it might be better to quit digging deeper while we still can; and spend money on other more fascinating fields of science; such as building new telescopes, preserve wildlife, fly people to Saturn via Mars etc. etc.

  26. #26 Sinisa Lazarek
    October 20, 2012

    “Physically we have reached the limit of what is physically measurable.”

    this is so untrue.

  27. #27 Fred
    October 20, 2012

    I agree with others that Chelle’s ignorance is breathtaking.

  28. #28 OKThen
    Why the LHC
    October 20, 2012

    The LHC is a most powerful and precise machine
    http://public.web.cern.ch/public/en/lhc/WhyLHC-en.html

    Even if the number of fundamental particles is limited there is a lot that is not known.
    http://public.web.cern.ch/public/en/lhc/LHCExperiments-en.html

    We will (and have already) learn much from CERN’s fundamental research program.
    Some of it will simply satisfy our curiousity; this is how the world works.
    – types of particle interactions
    – number of dimensions and size of dimensions (spatial and temporal)
    – relationship between emergent and fundamental particles

    Some of it will be very practical; this is how things work. Perhaps:
    – how to build powerful precise magnetic devices
    – femtometer (smaller and namometer) computing
    – specialty nuclear reactor (for space propulsion) or..

    We were born curious,
    It is our nature to taste the fruit of the tree of knowledge.
    And we will continue tasting. Yum.

    Our caveman ancestor protested in vain, “It is to dangerous; you will never understand fire and lightning and so on.”
    Because modern Luddites, you have learned to read and to master fire and electricity and the internet. So you are not so convincing when gobble gobble nonsense.

    But my dear Luddites, if you would protest with actions. Such as:
    – Living the Good Life by Helen and Scott Nearing or
    – Walden by Henry David Thoreau
    And if you have something profound to say about simple living; then you will read; and we will learn and be educated by you.

    But if you just talk gobble gobble gobble nonsense; we will roast you and toast you, “to a fine turkey.”.

  29. #29 chelle
    The Gods Themselves
    October 20, 2012

    OKThen,

    Why don’t you read this classic from Isaac Asimov just for fun :mrgreen:

    http://en.wikipedia.org/wiki/The_Gods_Themselves#First_part:_Against_Stupidity

    “Lamont discovers that the Pump is in fact creating a dangerous situation that could cause the Sun to become a nova”

  30. #30 Sinisa Lazarek
    October 20, 2012

    Chelle, do we need to warn you again?

  31. #31 chelle
    October 20, 2012

    SL,

    What I said is not so different from what ‘Wow’ said:

    “What if there are only a limited number of elementary particles and force carriers? At some point through discovering more and more you’d actually find that there really isn’t any more to discover.

    And me mentioning Isaac Asimov’s book was a response to OKThen’s book suggestions, I’m not a luddite, why point the finger at me?

  32. #32 Wow
    October 21, 2012

    Difference, chelle, you go all apeshit over “ignite some combustion process, because of the intense heat that is focused in one particular spot, during these collisions.” Which is errant bollocks (as usual).

    And you completely fake education by proclaiming: “You need a giant machine like the LHC that uses as much energy as a whole city to generate a bunch of particles that are of absolutely no practical use”

    I.e. the difference is that you’re anti-science and an idiot.

    At the very least I’m not anti-science, but open minded.

  33. #33 chelle
    October 21, 2012

    Wow,

    “And you completely fake education …”

    The energy use is correct, this is the number:

    “It takes 120 MW to run the LCH – approximately the power consumption of all the Canton State of Geneva. Need a better comparison? 120 megawatt is equivalent to the energy used by 1,2 million 100 watt incadescent light bulb or 120,000 average California home.”


    “the difference is that you’re anti-science …”

    It’s not because I don’t like one kind of stinky cheese that smell like dirty socks, that I don’t like cheese in general, i.e. I’m not anti-science.

  34. #34 Wow
    October 21, 2012

    Jessus frigging christ. When I quote only part of your work, you whine bitch and moan.

    Yet you do it liberally.

    READ THE WHOLE FRIGGING QUOTE YOU TWAT.

  35. #35 OKThen
    I can wait
    October 21, 2012

    Back to this asymptotic safety theory.

    The last 20 minutes of Weinberg’s 73 minute video is about about asymptotic safety. He concludes, “I don’t want to discourage string theorists, but there’s just the possibility that maybe that isn’t the way the world is, that the world is much more like we’ve always known, that is, the Standard Model and General Relativity.”

    OK it’s a possibility but above Bob says, “asymptotic safety model *does not work*” He sounds like he is reasonable.

    But I don’t know.

    I DO KNOW THAT sometimes a theory is good when we have 5 decimal place accuracy in data and that then things change dramatically when we get 6 decimal place accuracy.

    So overall, I’m not impressed with the precision of either theory or experiment yet. That gives me pause and reason to let the experts in theory and experiment do their excellent work.

    I’ll wait and watch. And try to learn, at least follow the discussion.

    A little later when I have time, I’ll give a paraphrase of my understanding of asymtptotic safety. So maybe someone can tell me if I’m thinking correctly or completely confused.

    Ciao.

  36. #36 Bob
    October 21, 2012

    Unbelievable, did anyone actually read the paper?
    It predicts the higgs mass to be 130 GeV, not 126 GeV, when you insert the recently measured top mass of 173 GeV.
    See equation (12)!

    Its funny how readers here just blindly accept Ethan’s summary, even though he admitted he doesn’t understand it, and he quit physics several years ago.

    This is really the blind leading the blind here on this blog.

  37. #37 Sinisa Lazarek
    October 21, 2012

    They have a +- few GeV to the result, so 126 and 130 are well in that range. Don’t see why the need for shouts and insults.

  38. #38 Bob
    October 21, 2012

    Sinisa, no, that is wrong. Have you actually looked at the ATLAS and CMS papers?
    ATLAS finds 126 and CMS finds 125.3. And the combined error bar from LHC completely rules out 130 GeV Higgs mass. So this rules out the prediction of this asymptotic safety scenario from 2009 which predicts higgs mass of 130 GeV. Thats just a fact… please don’t just go around denying facts.

  39. #39 OKThen
    171 GeV or 170.8 GeV
    October 21, 2012

    Bob
    Just a few points.
    You claim to have done the calculation that shows Higgs at 130 GeV.
    1) OK, I believe you but are you a PhD in Physics and if so what is your subspecialty?
    2) Two papers give different measures of Top Mass both papers are authored by 100s of scientists from Fermilab
    2a) Precise measurement of the top quark mass in the lepton+jets topology at CDF II, Jun27, 2007 “Using 167 events observed in 955 pb^-1 of integrated luminosity, we achieve the single most precise measurement of the top quark
    mass, 170.8 ± 2.2 (stat.) ± 1.4 (syst.) GeV/c^2.
    versus
    2b) Measurement of the top quark mass in the lepton+jets channel using the Ideogram Method, Feb 9, 2007, “In a data sample with an
    integrated luminosity of 425 pb
    −1
    , we observe 230 candidate events, with an estimated background
    of 123 events, and measure mt = 173.7±4.4 (stat + JES)
    +2.1
    −2.0
    (syst) GeV. This result represents the first application of the ideogram technique to the measurement of the top quark mass in lepton+jets events.”

    3) • mH = 126.3 ± 2.2 GeV per Authors: Shaposhnikov & C. Wetterich (2009)
    Idea: Assume that gravity is asymptotically safe, that there are no intermediate energy scales between the Fermi and Planck scales, that the gravity induced anomalous dimension of the Higgs selfcoupling is positive. Techniques: renormalisation group flow with mt = 171.2 GeV

    So unless you Bob tell me you are an expert in this area of physics; it seems to me that 171 GeV is correct and if not then 170.8 GeV.

    So please don’t argue this detail unless you are an expert. I am not so yes I will trust the published experts and Ethan’s interpretation of the published experts.

    And no I do not trust the Wikipedias 173 GeV is more correct than these reports or even understand the difference between the 170.8 GeV and the 173 GeV and why and when to use which number. Lots of details for the experts to understand, no you Bob (an ameteur) or me (an ameteur).
    .

  40. #40 OKThen
    What is asymptotic safety?
    October 21, 2012

    This my interpretation of what asymptotic safety is.
    I write this so an expert or someone who understands better than I can say, “Yep your are correct” or “No, your such and such statement is incorrect and here what would be better said.”

    1) classical physics uses classical fields (i.e. E&M, GR)
    2) quantum physics uses quantum fields theory QFT (i.e. QED and QCD)
    3) But QFT does not include gravity
    4) QED for the strong and weak force is renormalizable and
    QCD for the strong force is renormalizable in QFT but
    Gravity is not renormalizable in QFT so
    5) The Standard Model of Elementary Particles (which is a QFT) does not include the graviton because we don’t know how to renormalize a QFT of gravity and hence the graviton is omitted from the Standard Model.
    6) renormalizable simple means that the equations are sequences of terms and if those terms add up to infinity then the infinity has to be gotten rid of in some mathematical/physical way or else we got nonsense.
    7) QED, the E&M and weak force are renomalizable (i.e. can get rid of troublesome infinities)
    8) QCD, the strong force is renormalizable
    9) gravity is not renormalizable, i.e. we got troublesome infinities that we can’t get rid of; so we got no QFT of gravity and hence gravity is not part of the standard model of particles.
    10) BUT!!! there is a loophole.
    Even if gravity is not renormalizable everywhere; there are Fixed Points where by mathematical serendipity the troublesome infinities disappear. These fix points are called asymptotically safe Fixed Points. Because when you add up all of the terms of this incredibly complex mathematics; instead of diverging to troublesome infinities; at these Fixed Points the sum of all of the quantum gravity filed terms adds up to a finite number.
    11) Do not ask how this works. It is very hard math that some few theoretical physicists understand (a few hundred). So nice. Kudoos to these fine scientists.

    Now this far I think I am correct but now I need to speculate a little bit more.
    12) The asymptotic safety Fixed Points work well for our 4-Dimensional spacetime. Which is cool because that’s our observable universe.
    13) In QFT every point in the 4-Dimensional spacetime continuum is filled with a quantum field (which is different than a classical field).
    14) In classical field theory, every point of 4-dimensional spoacetime is not filled with a field (i.e. there can be points without classical fields). Not so in QFT.
    15) So in QFT every point of spacetime is filled with quantum fields of the 4 forces, QED (E&M and weak), QCD (strong) and Quantum Gravity (gravity). But we haven’t got a theory of Quantum Gravity.
    16)Well maybe we don’t need one! Because at certain Fixed Points that are asymptotically safe we can calculate the quantum gravity field sort of well enough.
    17)Now using our knowledge of all of the quantum fields (including gravity) those Fixed Points and using other data of the standard model (all of the masses of the standard model) and maybe knowing something about the universe (e.g. like the mass of the observable universe). Physicists can calculate the mass of the one missing particle of the stadard model.
    18) And as Ethan said, that calculation of the Higgs mass was done before the mass of the Higgs was experimentally measured.
    19) and Voila; they agree.
    20) So this idea of asymptotic safety has helped inch a little closer to a quantum theory of gravity. And for certain physics problems (not all) provides a way to do gravitational QFT calculations even without a Quantum Theory of gravity. VERY NICE.
    21) Now if asymptotic safety for quantum gravity (etc. etc. perfect assumptions and data) allows us to calcualte an exact Higgs mass 126.34562871657 GeV well then the game is over.
    No string theory, no extra dimensions, no supersymmetric particles, no technicolor, no preons, no axions, etc..
    22) But if asymptotic safety for quantum gravity allows an approximate calculation of the Higgs mass 126 + or – 1or 2 GeV; well then maybe string theory, extra dimensions, supersymmetry, technicolor, preons, axions, OR et. OR etc…
    23) ABSOLUTELY MINDBOGGLEING AMAZING WORK!
    GREAT JOB THEORETICAL PHYSICISTS

    OK, that’s my understanding by number 1 through 23.
    If you understand please correct me anywhere and everywhere.
    No ego here. I defer to your understanding.
    I just want to learn.
    Thanks.

    And thanks Ethan for bringing this exciting current physics topic to us.

  41. #41 Bob
    October 21, 2012

    Okthen, your ignorance is breathtaking. Why are you quoting 2007 vales for the top mass? Thr latest data prefers a central value of 173.2 GeV, while 171 GeV was ruled out long ago. For instance, here is a summary: http://arxiv.org/pdf/1205.2175v1.pdf

    Also, there is really no-one at any top institutions that care about this shaposhnikov paper, for several reasons (i) it conflicts with data badly, (ii) it conflocts with astronomical measurements of dark matter, (iii) it conflicts with the CP measurements (iv) it conflicts with inflation, (v) it conflicts with the observed matter/antimatter asymmetry, (vi) it conflicts with black hole microstate counting (vii) it conflicts with countless known aspects of gravity. Really, this is the only place that cares about this old paper.

    This is absolutely the blind leading the blind on this blog.

  42. #42 OKThen
    Dishonesty, deception, disparagement is not science
    October 22, 2012

    Bob

    The paper you point to is interesting.
    But you are not!

    You are a charlatan; not a physicists. You do not understand the research papers that you point to. You look for a sound bit to pretend knowledge and to use to disrupt honest discussion and learning.

    Your purpose here is not to learn science, not to educate about science; but only to disparage science and disrupt the learning of science.

    You come to this blog dishonestly, to misinform and to mock science.

    So tell us honestly Bob, what is your agenda that starts from a principle of dishonesty; what kind of falsehood and ignorance are you promoting because that is all that logically follows from the false assumption that misrepresenting yourself and disparaging honest search to understand can ever lead to or support “truth”.

    So Bob, give us a lttle of your honest insight, wisdom, knowledge.

    If as you pretend, you are really a physicsits who understands assymptopic safety and the insights that it gives into quantum gravity; then share your insight. Don’t point us to a research paper from which you have taken a soundbyte

    Yes, I’ve just read the paper that you pointed to; it changes nothing. There are several experiments that evaluate mass of the topquark and they have not resolved the issue yet. Asymptotic safety gives serious insight into quantum gravity. That is the important lesson here. It is not that asymptotic safety is the last word on quantum gravity.

    And yes, I have learned important physics from Ethan and the papers referenced on this post.
    I (we) have learned nothing from you. You are too cowardly to be honest even anonymously.

    As for the blind leading the blind. Yes that is how science works; we enquire, we hypothesis, we experiment, we learn from one another.

    No scientist desparages science like you. You do not learn from experiment; you use scientific knowledge to disparage scientific knowledge. You stick to your ignorance and your dishonesty and then you dare lecture on the blind leading the blind.

    You stick to some “last word” from some religion or political leader that pretends to be more correct in matters of truth even in matters of science.

    Go on I dare you to be honest about yourself. Tell us your source of truth, of the “last word”, of your religious or political guru who is not blind.

    Science is has a one eyed king and it is experiment, observation hypothesis, theory. It is not perfect but it is enough because it is honest and open. But yes, science is a matter of the blind leading the blind.

    Tell us about your one eyed king. Because yours is a case of dishonesty, misrepresentation, disparagement.
    Yours is a case of the blind misleading the blind.

    All my future comments to you Bob will be on Ethan’s comment page http://scienceblogs.com/startswithabang/2012/09/23/weekend-diversion-you-are-responsible-for-what-you-say/
    Go there, read it and keep your antiscience comments there. Yes, disparagement for disparagements sake is antiscience. And you have not shown one single insight suggesting rational intelligence.

  43. #43 Bob
    October 22, 2012

    So i point out the latest measurements of the top mass and its implications for the shaposhnikov paper, which is the subject of this blog entry. But instead of considering the data, Okthen says “it changes nothing”. Really, data changes nothing? And then Okthen goes on a nonsensical, illogical rampage.

    This blog sure does attract some crazies.

  44. #44 OKThen
    Bob you are warned
    October 22, 2012

    Bob
    This is your Warning.
    Continue to Ethan’s comment page http://scienceblogs.com/startswithabang/2012/09/23/weekend-diversion-you-are-responsible-for-what-you-say/
    Read it!

    I will continue my remarks to you there.

  45. #45 Pronoein
    October 22, 2012

    My god, this is the Pond. Ground zero of Graham’s pyramid: ” you twat! you ignorant! you charlatan! “.
    This is Ground zero: this is where intelligence is not happening.

    I find it so disturbing that Ethan allows such dogfights on a blog dedicated to science. Heinous barks fill the room.

  46. #46 Bob
    October 22, 2012

    I agree with Pronoein; OKThen’s behavior is disturbing and so is this blog.

  47. #47 OKThen
    Why no problem with equation 12
    October 22, 2012

    The paper
    Higgs boson mass and new physics by Fedor Bezrukov, Mikhail Yu. Kalmykov, Bernd A. Kniehl and Mikhail Shaposhnikov, Sept 27, 2012
    4 pages of section 2.2 analyzing Eqs 12 from the original paper (Yes, the eqs 12 that Bob aggitating about)

    “this computation (eqs 12 of the original) can be considerably improved… Table 3 summarizes the uncertainties in the new computation… One can see that the accuracy of theoretical computations and of the experimental measurements of the top and the Higgs boson masses does not allow yet to conclude with con fidence whether the discovery of the Higgs boson with the mass 124 127 GeV would indicate stability or metastability of the SM (standard model) vacuum. All these reference values of Higgs masses are compatible within 2 sigma with current observations.”

    So there is no problem within 2 sigma, according to the experts more detailed analysis as of Sept 27, 2012. http://arxiv.org/pdf/1205.2893v2.pdf
    Yes more theoretical and experimental work needs to be done and will be.

    If there is a more detailed analysis of eqs 12 from this Jan 12, 2010 paper http://arxiv.org/pdf/0912.0208v2.pdf.
    then please provide a link.

    Further analysis
    “Vacuum stability requires indeed the Higgs boson mass to be MH >∼ 129 ± 1 GeV, but the precise value depends critically on the input top quark pole mass which is usually taken to be the one measured at the Tevatron,m exp t = 173.2±0.9 GeV… This leads to the vacuum stability constraint MH ≥ 129.4±5.6 GeV to which a ≈ 126 GeV Higgs boson complies as the uncertainty
    is large.” http://xxx.lanl.gov/pdf/1207.0980v2.pdf

  48. #48 Wow
    October 22, 2012

    Oh dear, tone trolling, pronoun?

  49. #49 Zoran
    Belgrade
    October 23, 2012

    Forget about all that. Here is the return to sanity and commonsense:
    http://www.springerplus.com/imedia/1741190653821874_article.pdf
    Try and deny it. Think about it whichever reasonable way comes to your mind.
    “The noblest pleasure is the joy of understanding.” (Lenoardo da Vinci). Enjoy it! Physics is finally science. No need for mathematical mysticism anymore.

  50. #50 OKThen
    Zoran you are warned
    October 25, 2012

    For the psuedoscience inclined
    Zoran’s link concludes, “quantum mechanics, the string/superstring/M theories, the current particlephysics theory… are the results of tremendous intellectual efforts to model the reality, in a completely… fictitious ways… On the other hand, the photons-whirl concept is reasonable and understandable, clear and bright… (and has) unprecedented potential to explain everything.” etc.

    Zoran
    This is your Warning.
    Please continue to Ethan’s comment page http://scienceblogs.com/startswithabang/2012/09/23/weekend-diversion-you-are-responsible-for-what-you-say/
    Read it!

    I will continue my remarks to you there.

  51. #51 Wow
    October 25, 2012

    “On the other hand, the photons-whirl concept is reasonable and understandable”

    What is it about loons and a screwing universe that makes them lose their brain?

  52. #52 CB
    October 25, 2012

    I highly enjoyed reading the first couple pages of Zoran’s linked pdf. The style reminds me of the Illuminated Bibles where every third word has a parenthetical with five synonyms in it. Can’t we just define terminology in the beginning?

    But my favorite part was after starting off okay with real equations (inexplicably elevated to the level of axioms but whatever) it jumps the proverbial shark by going u0 *e0*deltaE = [all the permutations that show multiplication is in fact commutative] = deltaM. As in mass, the first time this is mentioned. And then it claims this is both the primary (primordial) definition of mass *and* the proper derivation of E=mc^2. Bam! Right smack into nonsense.

    Sorry for the clutter. I won’t mention it again. But for others who are done with the linked thread, I wanted to share teh funny.

  53. […] Have we reached the end of Particle Physics? (scienceblogs.com) […]

  54. […] Have we reached the end of Particle Physics? […]

  55. […] blogger Ethan Siegel has a fascinating article titled Have we reached the end of Particle Physics? I think this is a important as he thinks it is. This is the gist of it: there is a new idea gaining […]

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  57. #57 Melvin Goldstein
    April 8, 2013

    Numbers are the Supreme Court of science. However Godel proved that we may not prove everything. Physics needs numbers. There must be Physics Foibles!!

  58. #58 Sean T
    April 9, 2013

    Melvin Goldstein,

    Godel’s incompleteness theorem might have relevance to physics if we required a complete mathematical proof of an idea before we made use of it. Fortunately, we don’t do physics that way. The way it’s actually done is that an observation is made, a hypothesis is formulated to explain that observation, and then further observations are made to see if the consequences of that hypothesis are borne out by reality. If not, the hypothesis is rejected or modified. If so, the hypothesis, especially if there are multiple and independent observations supporting it, might well become a theory. No need for mathematical proof; theories are the ultimate goal of physics (and other sciences), but there’s NEVER proof of them. A new observation could overturn an accepted theory. When that occurs, Nobel prizes typically ensue. It’s a very rare and momentous occurrance.

  59. #59 melvin goldstein
    August 5, 2013

    Numbers are the Supreme Court of science. However Godel proved that we may not prove everything. Science needs numbers. There must be Science and Physics Foibles!!

  60. #60 Wow
    August 6, 2013

    Who’s a pretty boy then?

    Who’s a pretty boy then?

    Polly wanna cracker!

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