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Interviews: Giovanni Organtini Answers About the Higgs and LHC 123

Posted by timothy
from the for-greater-understanding dept.
You asked questions about the LHC (and in particular, the believed discovery of the Higgs Boson) of physicist Giovanni Organtini. Organtini has responded (answers below), and written a brief introduction to explain what the Higgs boson is and how it provides mass to other particles: "The Higgs mechanism was introduced to explain the fact that experimentally particles have mass. In fact, without the Higgs mechanism, the equations of motion for particles can only be written for massless particles. The actual mechanism is rather difficult to understand without a solid Quantum Field Theory background, but can be understood as follows: most of you know that particles gain some energy when they interact with a field. As an example, consider a book on a table. Since the book is subject to the earth's gravitational field, it has some potential energy that transforms into kinetic energy if it is free to fall. The potential energy depends on the mass of the book and on the intensity of the gravitational field. With the introduction of Special Relativity, however, we have to add an extra term to the energy of the book depending on its mass only (the famous E=mc^2). Introducing a special field (the Higgs field), we can turn this term into something similar to the gravitational potential energy, i.e. something that contributes to the energy of the book because it interacts with a field. The mass of a particle, then, is nothing but its potential energy in the Higgs field. The Higgs field is auto-interacting, i.e. it interacts with itself, as the electric and magnetic fields do. As the electromagnetic field can, the Higgs field can also propagate through space, but since it's auto-interacting, it gains some energy from itself, as the book gains energy from the interaction with it, resulting in the appearance of a mass for such a field, that becomes observable as a particle called the Higgs boson. You can find a more formal, yet simple, explanation of the mechanism here." Read on for his answers to reader questions.
Why is Higgs so elusive?
by jkauzlar

This may sound really dumb but the answers to the dumbest questions are sometimes the most interesting :) I understand that the Higgs is responsible for giving mass to all the other particles, then it must be *everywhere*. Why is it so difficult to detect? Why does it take such a staggeringly powerful supercollider to find what ought to be as common as the electron or proton?

Giovanni Organtini: The Higgs boson is unstable: once produced, it suddenly decays into pairs of particles. As a result, it cannot be found in ordinary matter as protons or electrons. It must be produced and observed soon after. In order to produce new massive particles, we are used to smashing other particles together. It happens that the energy E of the collision can "materialize" into particles, provided that E>=mc^2, where m is the sum of all the particles produced in the collision.

The Higgs boson mass is about 125 times the proton mass: it is quite heavy, in fact! The higher the mass of the particle to be produced, the higher must be the energy of the collision. Moreover, it turns out that protons are not elementary particles: they are composed of quarks and gluons, collectively called 'partons'. It is the collision between partons that produces the Higgs bosons. Partons carry only a fraction of the total energy of the proton. Then, we had to build a very high energy collider to produce such a Higgs boson, such that the collision between two partons happens with enough energy to create a Higgs boson.

There are other limitations, too: the production of a Higgs boson, even if the energy of the collision is enough, is a rare process, much rarer than the production of other particles like those we already know. The collider, then, must not be just powerful in terms of energy; it must also be 'luminous' enough, i.e. it must produce billions of collisions, such that the expected number of Higgs bosons produced is large enough to be distinguished from background.

"Also, I can't help but to visualize particles as something like billiard balls while I'm aware they're only mathematical abstractions from our point of view and that experiments like the double-slit experiment refute the billiard-ball model... is there a way to visualize the Higgs to make the answer to my previous question easier to understand?"

Actually, from the mathematical point of view, there is no such a distinction between particles and fields. Both are represented in the same way. In fact, in quantum mechanics, there are neither particles, nor fields, as we imagine them. The 'objects' behave like fields in certain conditions and like particles in different conditions.

This may sound frustrating to some people, but you have to consider that physics relies on experiments. We cannot tell the Universe how it should work: it's just the opposite! Despite the fact that we cannot figure out what a particle that behave like a field is, experiments tell us that, in our Universe, sometimes particles behave like fields. That's all! There is no reason for Nature to work as we would like it. Nature works irrespective of our ability to imagine how it works.

In my opinion the best image you can have of a Higgs boson produced at LHC is just like a billiard ball, in fact.

Energy to mass conversion?
by slashmydots

This is an IT worker question, not a particle physicist question, so hopefully it's an easy one. How does the Higgs boson come into play when photons, which have a tiny amount of mass, are spontaneously created when a substance like metal gets hot. Is it a direct energy to mass conversion?

GO: Photons do not have a tiny amount of mass. They are massless, as they do not interact with the Higgs field. When a metal gets hot, it's because you provide some heat — that is, a form of energy. You can always convert energy into particles (and vice versa) provided the total energy (i.e. including the rest energy mc^2) is conserved. As far as the metal glow, it gets colder, since the energy accumulated during heating is released in form of photons. There is no need for a Higgs boson in this case. Even this is not the case, energy to mass conversion is a common practice in high energy physics and is predicted by Einstein's Special Relativity. Each time we make two particles collide, they often produce new particles as a result of materialization of the energy of the collision.

The question, however, is interesting to discuss another feature. Despite that photons do not couple with the Higgs bosons, the latter were identified because of their decay into two photons. It may happen in quantum mechanics that a pair of particles 'annihilate' into photons. In this case, the Higgs bosons decay into a pair of quarks or vector bosons, that in turn annihilate producing two photons.

Is it higgsy?
by rwven

What success or failure factors can/should/will be used to determine whether or not the new particle is actually the higgs, or something else unexpected?

GO: We currently have just a measurement of the mass of this new particle. We also know, from its decays, that it must have spin-0 or spin-2. In order to be reasonably sure that this new particle is in fact a Higgs boson we must precisely measure its spin and we also have to observe and measure the predicted decays.

To complete this task we need a lot more statistics. It will take years, probably, to obtain enough precision.

That said, assuming that the new particle behaves exactly like a Higgs boson in its decays, there is in principle no guarantee that it is the Higgs boson, in the sense that all these measurements do not prove that the observed particle is the one that gives rise to the existence of mass! However, I cannot believe that we observed a particle that behaves exactly as predicted for a Higgs boson that is, in fact, something very different!

Analogies to magnetic and electric fields?
by FreedomFirstThenPeac

One press report discussed the idea that the Higgs field might have the same transient existence that the aether did in Electro-Magnetic theory. Do you think there is a field that will interact with the Higgs field to produce an energy transmission function similar to that described by Maxwell's equations?

GO: The Higgs field interacts with itself and as such is able to propagate more or less as electromagnetic waves. The only difference with respect to the e.m. field is that the latter is massless and propagates to infinite distances, while the Higgs field gets mass and materializes into a Higgs boson. Due to its finite mass, it cannot propagate too far, in fact. Actually a Higgs boson decays into matter particles in tiny fractions of a second.

Higgs and the Ether?
by Liquidrage

The likely Higgs discovery would seem to validate Quantum field theory. Would this then be best described as an ether, only instead of matter traveling through the ether, matter is a manifestation of the ether (fields) itself? Would this also than mean that the motion of matter is not a physical movement of a "particle" but instead the transfer of the "excitement" of a field from one spot of the field to another?

GO: That is an intriguing question. I am personally convinced that there could be some relationship between the Higgs mechanism, inertia and the fact that the speed of light is finite, mostly because the Higgs field is a scalar field (I do not want to enter into details, here, but this is the first observed spin-0 elementary particle). In my opinion what physicists called Ether could in fact be something related to the Higgs boson. It must be said that there is no coherent formulation of this. It's just a guess I make (and not very popular among other physicists).

As already said, there is no difference between a particle that moves and what you called an excitement of a field from one spot to another, in quantum mechanics. Both are the same thing.

And what, if any, implications does this discovery have for unifying gravity or other areas of physics?

GO: It is hard to say. Despite the Higgs hypothesis was formulated some 50 years ago, no convincing theory emerged yet, unifying gravity and other forces. In fact it is not yet clear why the inertial mass (the one provided by the Higgs boson) is equal to the gravitational mass (the source of gravity).

Inertial mass vs. gravitational mass?
by Omnifarious

The Higgs boson is famously associated with how particles acquire a 'mass.' But mass is, in itself, an interesting property. As I understand it, the Higgs boson is only associated with inertial mass. If this is so, do you expect gravitational mass and inertial mass to be always the same? If so, would you speculate on the mechanism that ensures this is true?

GO: In fact the Higgs boson provides inertial mass to particles. As far as we know inertial mass is something fundamentally different with respect to the gravitational mass: the first is responsible for inertia; the second is the source of the gravitational field. We have no idea about why the two masses are numerically equal. We do not believe in coincidences. There must be a reason for that, but we could not yet figure out it.

If you want me to speculate, I can imagine that gravity comes into play because the Universe tends to remain stable. The Higgs mechanism predicts that an empty Universe is unstable, while a Universe with some amount of the Higgs field is stable, because its energy is lower than an empty Universe. We call this condition the vacuum condition (i.e. vacuum does not correspond to 'empty', but to 'minimum energy'). What I imagine is that there should be some mechanism according to which fluctuations of the vacuum produces Higgs bosons that must interact in such a way that the energy of the Universe is conserved. And this may generate gravity. Though, again, I have not a coherent formulation of such a principle.

Applying the discovery in engineering & tech?
by globaljustin

Dr. Joe Incandela of UC Santa Barbara and CMS director said recently of the CERN Higgs results: "This is so far out on a limb, I have no idea where it will be applied, we're talking about something we have no idea what the implications are and [they] may not be directly applied for centuries." My questions: Do you agree that the direct application of the findings are as nebulous and abstract as he describes?Please discuss the implications of your answer and how they relate to the economic choices of how humans use their scientific resources.

GO: I completely agree with the above statements. Note that most important revolutions in technology and economy came much later with respect to a fundamental scientific discovery: we can use cell phones and WiFi because of Maxwell equations, GPS because of Relativity and all the electronics is an application of quantum mechanics. None of these discoveries were done having in mind any application. Moreover, no major breakthrough in technology or economy was achieved thanks to applied research. That is, in fact, a very good reason to support our activities.

That said, even if we cannot imagine possible direct applications of the Higgs bosons, we can for sure imagine possible applications of the technologies developed in order to detect it: large scale superconduction can save lot of money and energy savings, computing techniques needed to analyze LHC data are driving the birth of cloud computing, the detectors developed for these experiments can be used in different ways in medicine and industry. The past generation of experiments already generated some interesting spin-off: the new detectors for mammography, much more compact and precise with respect to the past, were developed for LEP experiments. Also the research on composite materials received a boost from our needs and are nowadays used to realize helicopters. Last, but not least, the world wide web as we know it today, is a CERN spin-off, developed to keep hundreds of physicists around the world updated about what was going on at CERN.

The future of the Higgs?
by Dartz-IRL

While I know it is rather early to comment, what do you think the future applications of today's research into Higgs Boson will be? Don't be afraid to be a little bit sky-high. I for one am already fantasizing about space ships propelled by manipulation of the Higgs field on a local scale. I'm only asking because, a century ago the electron was discovered and nobody was quite sure what to do with it. And it runs the world.

GO: As I said above, I cannot figure out any direct application of the Higgs boson itself. However I can imagine the birth of new techniques in manufacturing, energy production and transport, medicine and computing inspired by the technologies that we had to develop to discover the Higgs boson.

However, I don't want to escape the question and, being *very* sky-high, I can imagine that if we were able to isolate a region from the Higgs field (much as we use Faraday cages, i.e. metal boxes, to protect circuits from electromagnetic interferences), we can turn all the particles inside the region massless. You can imagine by yourself what this implies, for transportation, storage, etc.

What are the next incremental follow-ons?
by peter303

I heard they may want to check several other decay paths for energy resonances. I also heard there could be a family of Higgs bosons, so we may look for others?

GO: There are plenty of questions to which we need to provide answers, in fact. First of all we have to search for all the predicted decay paths for the observed resonance. There are theories predicting the existence of two or more Higgs bosons, and we need to discriminate between them. Some theory predicts charge Higgses, too. Moreover, even if the resonance is a standard Higgs boson, we are still left with the questions 'why different particles have different mass?' and 'why the masses are those observed?', just to be on the subject.

Needless to say that with the discovery of the Higgs boson we still have the problem to explain the estimated mass and energy of the Universe. With the known particles we can explain less than 10% of the mass of the Universe. There must be other weakly interacting particles (called dark matter) providing the missing energy, that we have not yet discovered.

Significance of Higgs Boson mass?
by SpinyNorman

As I understand it, a Higgs Boson compatible with the standard model could have been found at a range of different masses, and the search for it has involved searching the possible mass range until it was either discovered or not. Assuming that this new discovery is indeed the Higgs Boson as predicted and compatible with the standard model, what is the significance of the particular mass that it has been found to have? Are there any macro-scale predictions that depend on its mass?

It means that with this mass, a Higgs boson can be accommodated in any 'reasonable' theory. In other words, the Higgs boson has the observed mass because it cannot have any other mass. Any other mass would cause the Universe to behave differently at different scales. This is an important fact. If something similar is proven for other fundamental constants, we can get rid (at least partially) of the (in)famous anthropic principle: the world is as we observe it because, whatever the initial conditions, it must necessarily evolve in the current state!

The Best of the Worst Science Reporting?
by eldavojohn

In regards to the Higgs Boson, what's the stupidest thing you've seen in the press? Has anything in particular made you really laugh or groan? Has the reporting been overly irresponsible for this discovery process or just the same old press that you're used to?

GO: Incredibly enough, for this discovery I didn't find something particularly funny in the press. As I am a bit conceited :-) I can attribute the merit to our communication teams, that in fact did a great job this time.

The nickname given to that particle (the 'God' particle) makes me laugh a bit. But in this case the one responsible for this is a physicist: Prof. Leon Lederman, who gave this title to a book of his about the Higgs boson. According to what can be read, in fact it was the publisher that chose that title, but manifestly Prof. Lederman must have agreed. In this case journalists just used that nickname, which obviously sounds appealing.

SSC
by Michael Woodhams

Had the superconducting supercollider (SSC) been completed in the USA in the 1990s, would it have found this particle? Even with a 20 year technology advantage, LHC has taken some time to get there.

GO: The plan for the SSC was to achieve a higher energy with respect to the one planned for LHC. In fact we are still using LHC at half of its maximum energy, for safety reasons. Hence, in principle, SSC would have found it.

However, a discovery like that is not just a matter of energy and luminosity. The possibility to find the Higgs boson is strongly related to the available computing and networking technologies that evolve much faster than detector's technology.

Use of military tech in physics?
by solidraven

How do you feel about the fact that a large portion of the CMS was built by recycling military hardware? Do you see it as a sign that the world is finally moving towards peace and that large scientific projects like the LHC are helping it along that path; Or do you find it disappointing that it was the only option to acquire the necessary materials?

GO: I am happy with the fact that a portion (not so large, in fact) of the CMS was built by recycling material, irrespective of its provenance. I believe that we should learn recycling much more than what we do now, not only in building detectors (on the other hand we build a new detector like CMS every 15-20 years). Then I don't see why I should be disappointed. Recycling should not be seen as a last resort to exploit when money is lacking; its should be regarded as an opportunity for the whole of mankind.

The fact that, to build CMS, weapons were destroyed, well, is exciting! The less weapons on earth, the better the life for humans. I'm glad to be part of an experiment who helped in making weapons disappear.

Open Data?
by eldavojohn

Since you're a fan of free software, why don't we see more open data efforts in particle physics? I see headlines like this and they're kind of a turn-off. Aside from this super-confusing applet I haven't been able to find torrents of the data available on these tests. Why is that? I mean, as a software developer there is a legitimate effort of folks writing open source software and then there's a legitimate effort of people using that software to accomplish many things and everyone deserves credit. So why are particle physicists so keen on being the collectors and (at least initially) the sole keepers of their data? It would seem to make sense to me that people should be rewarded based on their collection of data and how meticulous and well they do that while any group can consume and derive results from said data. I understand the process has gotten more open but why so slowly? Why not torrent your data to whoever wants it immediately after you get it?

GO: Let me first state here that I'm in favor of open data, whatever they come from. Then, I will support any action to make more and more public our data, too.

There is, in fact, some reluctance to make scientific data public, also by scientists that use and promote open source software. I believe that this attitude has sociological bases and with time will vanish, as is happening with software.

That said, not only particle physicists tend to keep their data. As far as I know, in most scientific projects data (at least raw data) can be accessed only by those who collected them. The only exception I know is in astrophysics where, however, there is an initial period in which only the principle investigator's team can look at data collected by telescopes or satellites. This is comprehensible since who had a brilliant idea about how to make some observation, want to keep for himself the right to publish the result that, in few cases, can be straightforward to obtain once you have the data.

It must be said that in particle physics this is not the case. And in particular for LHC. Data are extremely complex and it is not at all easy to extract interesting signals from it. You must also consider that we produce of the order of 1 to 5 PB of data per year and it is impossible for anyone not owning a large computer centre to download even a small portion of them. You should also consider that the physicists working on these experiments already saturate all the available resources (in terms, e.g., of bandwidth, storage and CPU) and, of course, we do not want to reduce our quota of resources just to make data public.

Thanks to Dr. Organtini for these answers. Do you have ideas for leads for more Slashdot interviews? They're welcome at feedback@slashdot.org!
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Interviews: Giovanni Organtini Answers About the Higgs and LHC

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  • Awesome, more please (Score:5, Interesting)

    by vlm (69642) on Tuesday July 24, 2012 @03:08PM (#40753987)

    Not many comments on this story because its awesome. Or maybe I'm a faster reader than the rest of you. More /. interviews like this, please!

    • in quantum mechanics, there are neither particles, nor fields, as we imagine them. The 'objects' behave like fields in certain conditions and like particles in different conditions.

      Could it be that a "particle" is where two waveforms intersect?

      • by crgrace (220738) on Tuesday July 24, 2012 @04:24PM (#40755303)

        Could it be that a "particle" is where two waveforms intersect?>

        unlikely. What you are describing is constructive and destructive interference. That has been observed for particles (the famous double-slit experiment). We can have a particle with "one" waveform, so there is nothing to intersect.

        • by Anonymous Coward

          Could it be that a "particle" is where two waveforms intersect?>

          unlikely. What you are describing is constructive and destructive interference. That has been observed for particles (the famous double-slit experiment). We can have a particle with "one" waveform, so there is nothing to intersect.

          True, but see also this. [wikipedia.org]

      • by Guy Harris (3803)

        in quantum mechanics, there are neither particles, nor fields, as we imagine them. The 'objects' behave like fields in certain conditions and like particles in different conditions. Could it be that a "particle" is where two waveforms intersect?

        No, a "particle" is a quantum of a quantum field [wikipedia.org].

    • by Megahard (1053072)
      Here's the reason there's so few comments.
      http://www.youtube.com/watch?v=VyiYJl7QZhQ [youtube.com]
    • Most interesting/awesome part of answers, IMHO:

      "I can imagine that if we were able to isolate a region from the Higgs field (much as we use Faraday cages, i.e. metal boxes, to protect circuits from electromagnetic interferences), we can turn all the particles inside the region massless. You can imagine by yourself what this implies, for transportation, storage, etc."

      In response to a second question about future applications. "Future of Higgs?"

      Forgive my crude drawing above, but if I understand correctly, he

      • my drawing was supposed to look like this: ">|_|>" but i typed the wrong character

        sort of a prototype of a flying saucer...or the LEM Research Lander the Apollo astronauts used: http://en.wikipedia.org/wiki/File:Lunar_Landing_Research_Vehicle_in_Flight_-_GPN-2000-000215.jpg [wikipedia.org]

      • Just want to mention that for all the "ordinary" particles, that is the hadrons, the Higgs contribution is only part of their mass. Only the mediators of the weak nuclear force, the W- and Z-gauge bosons, get all their mass from the Higgs mechanism, which is the reason why this force is short-ranged, as opposed to for instance the electromagnetic force mediated by photons, which is (infinitely) long-ranged.

      • by Guy Harris (3803)

        Forgive my crude drawing above, but if I understand correctly, he's saying we can make a "Higgs Cage" that would make what's inside of it massless...

        No, he's saying that if we could do that, then there might be some interesting applications; the answer you quoted said "I can imagine that if we were able to isolate a region from the Higgs field (much as we use Faraday cages, i.e. metal boxes, to protect circuits from electromagnetic interferences), we can turn all the particles inside the region massless." (emphasis mine).

  • by Anonymous Coward

    Brandon's Mom: Where are you going with those fireworks?
    Brandon: Well, the Protector got super-accelerated coming out of the black hole, and it, like, nailed the atmosphere at Mach 15, which, you guys know, is pretty unstable, obviously, so we're gonna help Laredo guide it on the vox ultra-frequency carrier and use Roman candles for visual confirmation.
    Brandon's Mom: Uh, all right, dinner's at seven.
    [Brandon exits. Mom turns to a dubious Dad]
    Brandon's Mom: Well, he's outside.

    http://www.imdb.com/title/tt0177 [imdb.com]

  • by tphb (181551) on Tuesday July 24, 2012 @03:30PM (#40754337)

    Great questions and very well-written answers.

    • by MightyMartian (840721) on Tuesday July 24, 2012 @03:36PM (#40754425) Journal

      Indeed. This is probably one of the best /. articles in a very long time. Unfortunately, what's there to comment about it? Most of us have nowhere near the level of knowledge to do much more than go "Okay... that kinda makes sense."

      The important thing for me to come out of this is to defend very expensive quests like finding the Higg's Boson by pointing out that even if we cannot fathom an application for confirming the Standard Model now, we cannot predict how that research may play out in the decades or centuries to come.

      To my mind, we're handing our descendants a bucket full of shit; pollution, climate change, environmental destruction, short-minded use of large amounts of non-renewable resources, all of which is going to make things much more difficult for them. At the very least we can also hand them some quality basic research and confirmations of theories so they can leap off our shoulders and solve some of our messes (and theirs too of course).

    • Can we do one of these /. Q&A's with Brian Greene? String theory is another almost-impossible-to-understand subject and his 1999 Elegant Universe [wikipedia.org] is a bit old now. He must have plenty of new thoughts on the subject.
  • by Anonymous Coward

    The first question asks how come if the higgs gives everything mass, and is therefore presumably available just about everywhere that there are things that have mass, how come its so hard to find.

    And the answer... doesn't address it. It just says that they're really rare and they dont last long and they're really hard to create even temporarily.

    So, back to the question: how are they responsible for giving everything mass if there's hardly any of them anywhere, they don't last long and they're really hard to

    • by MightyMartian (840721) on Tuesday July 24, 2012 @03:43PM (#40754575) Journal

      Read it again. The Higg's Field gives a lot of other particles mass. In quantum field theory, particles and fields are essentially facets of the same phenomena. Thus, the Higg's Field (which is what gives many particles mass) and the Higg's Boson, are really two sides of the same coin. The point to finding the Higg's Boson is that it confirms the existence of the Higg's field.

      Quantum field theory is very well confirmed, by the way, and it was no less than Albert Einstein (despite his later dislike of QM) who was a major instigator due to his research into photons and electromagnetic field theory. So study up on how that works so far as electromagnetic radiation is concerned, and then apply the same field concepts to Higg's.

    • by r1348 (2567295)

      It is my understanding (and I'm no physicists so take what i say with a pinch of salt) that it's the decay of the Higgs boson what gives mass to other particles.

      • by crgrace (220738) on Tuesday July 24, 2012 @04:30PM (#40755397)

        It is my understanding (and I'm no physicists so take what i say with a pinch of salt) that it's the decay of the Higgs boson what gives mass to other particles.

        It isn't the decay of the Higgs boson that gives mass to other particles, it is rather the interaction of these particles with the Higgs field that gives them mass. A boson is a particle that conveys a force, its decay is not the means of conveyance.

    • by Ixokai (443555) on Tuesday July 24, 2012 @04:38PM (#40755525)

      IIUC, and I didn't even think I understood it at all before this well-written article, you're confusing the Higgs Boson and the Higgs Field.

      The *particle* -- the boson -- does not give anything mass, the *field* does. Particles interact with the field, and have inertial mass as a result. But we can't detect the field. However, since particles and fields are the same thing, we /can/ in theory detect occasional blips in the field, when the energy of the field materializes as the particle. (E=mc2) That's very rare, and those don't last very long, which is why its elusive.

      But those particles aren't what's important. They don't give everything mass, they aren't everywhere: they may have been around at the start of the universe when everything was all bursting with energy and such, but they quickly decayed; the field persisted though, and that underlining /field/ of the same name, is everywhere.

      I think.

    • by jdray (645332)

      Dunno, but I am looking forward to gravity decking! :D

    • by Chris Burke (6130) on Tuesday July 24, 2012 @05:42PM (#40756641) Homepage

      What his answer describes is why it's so hard to create a free Higgs Boson that we can observe in our detectors through its decay paths. The missing part of the answer, the gist of your question, is what about all the Higgs Bosons that are busy giving rest mass to the detector and everything else in the universe? The answer is that those bosons are, by necessity, virtual ones where "virtual" means "unobservable".

      I'm going to switch gears to something I know about but where the same principle applies: Electromagnetism and photons. Photons are a type of boson, similar to the higgs but massless, and they mediate the electromagnetic interaction.

      When two charged particles interact, they do so by exchanging a photon. This transfers momentum creating the repulsive force between electrons. In this interaction, the photon's world line begins at one electron and ends at the other. That's its whole existence. So you can't intercept it in the middle -- if you could that would mean the electrons hadn't interacted in the first place, and you had blocked the EM interaction (like with the Faraday Cage he mentioned). This is why you can't see the photons flying back and forth between the plates of a capacitor. Those photons are unobservable, or virtual.

      Now in addition to these electrostatic interactions creating virtual photons, you can disturb the EM field and create a 'real' photon, one which can be observed. Because photons are mass-less and have energy based solely on the wavelength which can be arbitrarily long, they can be created very easily. Even exceedingly cold objects emit real photons from the excitation of charged particles inside them.

      The Higgs Boson, on the other hand, is massive object so to create a real one suffers from the problems Dr. Organtini describes.

      • by mestar (121800)

        So does this mean that when you are looking at a star, your eye is repulsed or attracted by the star via photons?

        • by sFurbo (1361249)
          Yes, your eyes are pushed away from the light. So is the rest of you, at least the parts the light hits. That is the idea behind a solar sail [wikipedia.org]. Of course, the force is minute, and hard to even measure in the atmosphere.
          • by mestar (121800)

            Then, what exactly is the difference between real photons and those virtual photons mentioned in the gp?

      • I don't understand why people continue to confuse the Higgs field with the Higgs Boson. They are not interchangeable....

      • by Chris Burke (6130)

        Oh, I should mention that virtual particles are part of Perturbation Theory, which is a particular mathematical treatment of Quantum Field Theory. The one where you can use Feynman Diagrams to figure out what you're actually supposed to be calculating.

        What's interesting is that in Perturbation Theory, virtual particles are allowed to actually violate Conservation laws briefly so long as it falls below the Uncertainty Principle limit (so the Universe can never knows it happened).

        In non-perturbation theories

  • I sort of get what this Higgs Boson is, and if this field gives mass to particles, what gives mass to this Higgs Boson? I mean, if you go down deep enough, their must be some sold object that makes up all this energy, or is energy just an infinite level of density?
    • Re: (Score:2, Informative)

      by Anonymous Coward
      The Higgs boson does indeed interact with and get its mass from the Higgs field.
    • by rcuhljr (1132713) on Tuesday July 24, 2012 @04:03PM (#40754943)
      I believe that's what he meant by the field being self interacting. It effects itself.
      • by na1led (1030470)
        Is there anyway to visualize this?
        • by Anonymous Coward
          *crickets*
        • An EM field interacts with itself, too. If an EM field happens to be moving around, its self-interaction causes itself to look and act particle-like. We call this a photon. Replace EM with Higgs, and re-visualize.
          • by Guy Harris (3803)

            An EM field interacts with itself, too.

            So there's a Feynman diagram that's all photons all the time? How does a neutral particle such as the photon interact with an EM field?

            • by Guy Harris (3803)

              An EM field interacts with itself, too.

              So there's a Feynman diagram that's all photons all the time? How does a neutral particle such as the photon interact with an EM field?

              See also a sci.physics.particle discussion [google.com] which notes that the answer to my (rhetorical) question is "no", at least in the Standard Model (there are fermions in the diagram as well). (And, no, that mediated interaction isn't what causes particle-like behavior from an electromagnetic field.)

          • No, an EM field doesn't interact with itself. You can see that if you try to deflect the beam of a flashlight with the beam of another flashlight: You'll not succeed.

            Another field which does interact with itself is the QCD field, which is responsible for the strong force. Here the self-interaction is responsible for the fact that you cannot separate the quarks of a hadron.

        • A way to visualize quantum field theory? I think not.

          I'm still looking into a way to understand it.

    • the higgs field interacts with itself. Or if you prefer, the boson interacts with the field, and the field gives mass to the boson. At least, that's roughly what I took from the article.

      • by na1led (1030470)
        So the Boson makes up the field, or the field makes up the Boson? How can something be made up of itself?
        • How can something be made up of itself

          I don't know the correct answer but if I would, it would be vulgarized with that analogy: My dick is made of me, but my dick is not myself since he has a mind of his own and we sometime self-interact.

        • by slew (2918)

          So the Boson makes up the field, or the field makes up the Boson? How can something be made up of itself?

          Although it is not technically correct, the way I like to think about it is virtual Bosons make up the field, and the field is from what the Boson is created. In some situations the virtual Bosons can be converted to real Boson which completes the circle... Virtual Bosons seem to be mostly just the accounting trick for balancing in quantized field unit interactions, but with the proper situation, just like monetary accounting tricks, you can convert that back into the real thing ;^)

        • Here's the crux of quantum field theory. The particle and the field are the same thing. Like photons and other force mediators, whether you describe it as a particle or as a field, you are talking about an attribute of the same thing.

  • by dmbasso (1052166) on Tuesday July 24, 2012 @03:36PM (#40754411)

    ... in the Higgs field.

  • Thanx to Dr. Organtini and the people responsible for this.

    Almost enough here for somebody to figure out how to decouple Inertial and gravitational masses!

    myke

    • by jd (1658)

      If the two are distinct but numerically the same, then you must introduce some mechanism to couple the two.

      Do we have any mechanisms for coupling two particles, such that one particle will have a state that has the same absolute value as the other particle?

      Weeelll, yes we do, but I can think of no obvious reason why gravitons and Higgs bosons would be entangled, nor why those which were entangled would be found solely in the same object. As such, although it could conceivably be something like that, I am no

  • by Greger47 (516305) on Tuesday July 24, 2012 @03:52PM (#40754737)
    So I read the arXiv paper which was quite understandable, but on page 5 it suddenly throws in a phi^4 term:

    It is easy to show that adding a term like phi^4 to the energy density, the latter reaches its minimum for a field phi != 0.

    And suddenly vacuum isn't empty any more. Why is that? What is the motivation for adding that phi^4 term out of nowhere?

    /greger

    • Re:Wait, phi^4 what? (Score:5, Informative)

      by crgrace (220738) on Tuesday July 24, 2012 @04:27PM (#40755357)

      Vacuum hasn't been "empty" for almost 60 years. John Wheeler coined the term quantum foam in the 50s to describe the fact that even vacuum must essentially be boiling in a sea of virtual particles to satisfy Heisenberg.

    • by jd (1658)

      As noted in the Q&A session above, a vaccuum is the minimum energy state, not an empty state. An empty state actually has greater energy than a vaccuum.

      Another way to look at it is that an empty state must have zero entropy (forbidden by the laws of thermodynamics). Physics doesn't work well with zeros. Physics allows you to have a system which -averages- out to zero, which is what quantum foam does, but it doesn't permit any individual point in that system to have a zero state.

      Quantum foam is the prefe

    • That question is a bit difficult to answer. Let me try a few, hopefully one of them helps you.

      1) It's there because it works. A large part of high-energy theory is what is called model building, where people build models that at the least agree with previous knowledge and are internally consistent. Hopefully they also explain something not explained before. Such a phi^4 potential term is very natural to try (cannot elaborate on that here), and gives the Higgs boson and mechanism as we know it, and thus the

  • by Anonymous Coward

    "Moreover, no major breakthrough in technology or economy was achieved thanks to applied research"

    I couldn't disagree more. All major breakthroughs are strictly on the back of applied research. However, all applied research relies solely on basic research. It falls under the "shoulders of giants" argument.

    • "Moreover, no major breakthrough in technology or economy was achieved thanks to applied research"

      I couldn't disagree more. All major breakthroughs are strictly on the back of applied research. However, all applied research relies solely on basic research. It falls under the "shoulders of giants" argument.

      I was about to post an angry protest of this as well, and I'd go even farther than you did. Plenty of things are developed from applied research that are barely even related to basic research. Take the airplane, for example. The concepts of lift and drag, and their relationships, owed relatively little to the basic research being done in the 19th century on the nature of air (ideal gas law, etc.) and much more to the design and application of wind tunnel testing. Anyone who works in fluid dynamics owes

  • It's kind of like that Far Side...Just substitute "Higgs Boson" for "Ginger" and you'll get the idea. http://tinypic.com/r/2144k8w/6 [tinypic.com]
  • Last time I read up on this subject, the only postulated spin-2 particle was the graviton. I'm starting to lean towards a result of "what we found turns out to be a clump consisting of a graviton and some arbitrary collection of virtual bosons that gives the resulting 'particle' mass", especially if the determination is that the found particle is (to a high degree of likelihood) spin-2.

    • by Guy Harris (3803)

      Last time I read up on this subject, the only postulated spin-2 particle was the graviton. I'm starting to lean towards a result of "what we found turns out to be a clump consisting of a graviton and some arbitrary collection of virtual bosons that gives the resulting 'particle' mass", especially if the determination is that the found particle is (to a high degree of likelihood) spin-2.

      ...and especially not if the determination is that the found particle is spin-0; that would leave no need to drag in the graviton.

      • by mdenham (747985)

        Well, at that point we still have the "why are inertial and gravitational mass the same" question. If the Higgs turns out to be a graviton-and-other-stuff composite, that potentially neatly ties that particular question up (loosely explained, they're the same because the graviton forms a component of the Higgs field in this situation).

        That said, the found particle having spin-0 doesn't necessarily rule out it being a graviton composite (there's spin canceling going on in baryons - for example, a proton con

  • by Anonymous Coward

    Giovanni Organtini messes up a bit answering this question (most particle physicist are no experts on gravity). First, it is true that inertial mass of fermions and weak bosons comes from the Higgs mechanism. But this mechanism is not related to why gravitational mass is exactly equal to inertial mass. This comes from the equivalence principle which can be stated in different but equivalent ways (the most usual being the geometrical of general relativity), I will give another statement (hopefully in simple

  • It's my understanding that this boson was not discovered before LHC because it was too massive to produce in a lesser accelerator; however, the top quark was produced at Fermilab some years ago, and it has a larger mass (Higgs @ 125GeV, top quark @ ~171GeV). Does anyone understand why this is? I know I am missing something here...
    • by mdenham (747985)

      I believe the LHC has a higher luminosity than the Tevatron, which for low-probability results means you don't have to run the device as long to see results.

    • by Old Wolf (56093) on Tuesday July 24, 2012 @09:04PM (#40759329)

      It's my understanding that this boson was not discovered before LHC because it was too massive to produce in a lesser accelerator; however, the top quark was produced at Fermilab some years ago, and it has a larger mass (Higgs @ 125GeV, top quark @ ~171GeV). Does anyone understand why this is? I know I am missing something here...

      The top quark is easy to detect, as its most common decay channel is fairly distinctive. But 99.999% of the Higgs decays are into things that are indistinguishable from other by-products of the collisions that generated the Higgs boson in the first place. Fermilab and the other colliders definitely would have generated many Higgs bosons, however they just couldn't amass the volume of data required to pick the Higgs decays out of the background. The LHC wins here not because of its energy, but because of its sustained luminosity.

      In fact, Fermilab has published plots that do show small bumps at the Higgs boson mass [discovery.com] - but in themselves, the statistical significance is not nearly enough to make a discovery.

  • Great article. One quick correction from a practitioner in the field: there is plenty of open source software in use in and developed by science. Care for a useful example? The Scientific Linux distribution [scientificlinux.org] of Fermilab and CERN is a good example, very accessible to everyone. (And there is that whole World Wide Web thing - not exclusively open source, but still pretty darn useful!)
  • I asked about the technical application of work like the Higgs research at CERN and he responded.

    "even if we cannot imagine possible direct applications of the Higgs bosons, we can for sure imagine possible applications of the technologies developed in order to detect it"

    To Dr. Organtini,

    Thank you for your time in responding. I appreciate your humble insistence that the universe tells US how IT works.

    _justin

  • I can imagine that if we were able isolate a region from the Higgs field (much as we use Faraday cages, i.e. metal boxes, to protect circuits from electromagnetic interferences), we can turn all the particles inside the region massless.

    I know he was just theorising, but if it is possible to isolate regions of space from the Higgs field, thus reducing the mass of the contents, then wouldn't that explain where the missing dark matter in the universe is? Could it simply be located in areas of space where th

    • by mdenham (747985)

      The problem is that there should be more mass than is observed. So theoretically there might be areas where the Higgs field is stronger, which would obviate the need for dark matter, but then the question becomes "why is the Higgs field stronger here?" (Well, that's one of the questions. Another question then obviously becomes "Does dark energy have the side effect of increasing the Higgs field strength?", and if the answer to that question is "yes"... well, I believe one outcome is "we get a Big Bang w

  • by Old Wolf (56093) on Tuesday July 24, 2012 @08:42PM (#40759139)

    I understand that the Higgs is responsible for giving mass to all the other particles, then it must be *everywhere*. Why is it so difficult to detect? Why does it take such a staggeringly powerful supercollider to find what ought to be as common as the electron or proton?

    A poster asked the above questions, which G.O.'s reply did not actually address. The Higgs field is everywhere, and gives mass to many (not all) of the other particles. In a sense, we detected it long ago when we noticed that things have mass. The Higgs boson doesn't give mass to anything.

    Why is the Higgs boson not as common as electrons or protons? A particle is the smallest possible ripple in a field. It so happens that the electron field has its smallest possible ripple of mass 0.511 MeV, but the Higgs field has its smallest possible ripple of mass ~125300 MeV , about a quarter of a million times more energetic. If the collision only produces 100 MeV of energy, for example, there's not much chance it'll be able to make a Higgs boson, but it could make a lot of electrons.

    Why is the Higgs boson so hard to detect? It has a short lifetime (by human standards) and quickly dissipates into other particles (much like how a vibrating guitar string dissipates into vibrations in adjacent fields such as the guitar body, the surrounding air, the guitar head, your hand, etc.). However, the vast majority of its decay products are the same things that are produced in the collisions that we used to create the Higgs boson in the first place; for example if we detect a pair of bottom quarks, we don't know whether they came directly out of the proton-proton collision, or whether that collision produced a Higgs boson that then decayed into a pair of bottom quarks.

    The main way that we're detecting the Higgs boson is by it decaying to two photons. Of course, photons come directly out of the collisions too, but they have a smooth frequency (energy) distribution. But the Higgs decay photons always will add up to the mass of the Higgs boson. So we plot the photon output of the collisions against their frequency (energy), and look for a bump.

    It happens that the energy E of the collision can "materialize" into particles, provided that E>=mc^2, where m is the sum of all the particles produced in the collision.

    Virtual particles don't follow this rule (a virtual particle is really a disturbance in the field that isn't the right sort to become a self-propagating ripple, so it dissipates straight away. This can have any amount of energy). For example, one of the Higgs decay channels (or production channels) is H -> ZZ. But Z bosons have a mass of 91 GeV , so two Z bosons weigh nearly 50% more than the Higgs boson. So, at least one of the Z's must be virtual; careful writers will call the process H -> ZZ* to indicate this. What actually happens here is that the energy of the Higgs boson dissipates into the Z field, and from there it quickly dissipates again into other fields. This does happen despite the fact that it didn't create two real bosons in the Z field on its way.

    Actually, from the mathematical point of view, there is no such a distinction between particles and fields. Both are represented in the same way. In fact, in quantum mechanics, there are neither particles, nor fields, as we imagine them. The 'objects' behave like fields in certain conditions and like particles in different conditions.

    This is like saying there's no distinction between oceans and tsunamis. But there is; the tsunami is a self-propagating ripple in the ocean. Just as a particle is a self-propagating ripple in a field. There's only one field (of each type) and it's everywhere, and it's normally off unless there's a ripple passing through. (The Higgs field is unique in that it's always on).

    in our Universe, sometimes particles behave like fields.

    That just doesn't make any sense. It's as if

    • by Anonymous Coward

      Firstly, the guy does state that he is speculating. Trying to make a point of that despite the disclaimer makes you sound like an asshole.

      Secondly, the fact that the inertial mass is the same as gravitational mass is interesting. Gravitational mass result in curvature on space-time, inertial mass is the result of the ripples in the Higgs field. Their associativity is related to the quantum-mechanics and gravity connection, which is still an unsolved area in physics.

      • by Old Wolf (56093)

        Trying to make a point of that despite the disclaimer makes you sound like an asshole

        I'll admit that I used a sensational title, hoping to avoid my post never getting read!

        Secondly, the fact that the inertial mass is the same as gravitational mass is interesting. Gravitational mass result in curvature on space-time, inertial mass is the result of the ripples in the Higgs field. Their associativity is related to the quantum-mechanics and gravity connection,

        Inertial mass (of quarks, Zs, Ws, electrons, muons, and taus) is the result of them interacting with the Higgs field even when there were no ripples present in it. The Higgs field is always on, you could almost think of it as one giant particle that has unlimited energy and has 100% chance to be found at any point in space.

        The idea of 'curvature of space-time' comes from general relativity, which basically says that ther

  • It is interesting that charge Higgses were mentioned. As a physics undergraduate I remember asking my supervisor, if the Higgs causes mass, then what causes charge? To me, mass and charge are equally essential properties of a particle, so why would we look for the cause for only one of them? Of course, mass is kind of special in that it gives inertia; no matter what the force on a particle is, it needs to deal with its inertia.

    Moreover, the way that different particles acquire different masses means that

    • by Anonymous Coward

      It might be a little early for you to appreciate the answer, but you will get there. The reason is that the lagrangian of the standard model doesn't like to have mass terms (i.e. terms that give mass to the fields) because they break chiral symmetry. So the lagrangian of the standard model (lagrangians specify the theory) can't have mass terms, but we see mass around. So we had to think some other mechanism that gave mass to particles, this is Higgs mechanism.

      Now, the same doesn't happen to other charges (m

      • by TeknoHog (164938)
        Thanks for the reply, I knew there had to be an obvious explanation. BTW, I finished my undergrad degree 10 years ago, and I understood everything in your post, but I have since moved to engineering and education.

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