Higgs field

I always hate to ask these type of questions. But reading on the Higgs field, it reminds me of the theory of ether, in some ways.

Perhaps. But I don't see it's surface resemblance to ether as being something that tells us very much. It would be as informative as referencing Democritus' atomic theory. It's an interesting historical aside, to be sure, but still a lucky guess.

I can see the connection - that of aether in the 1900s.

It's vaguely plausible, but as yet vrey little experimental evidence. There is some data out there and within wide margins space for the 'aether'. Obviously most standard model physicists are hoping the LHC won't be a Michleson-Morley. But if it is it will open up such a wide range of discussion that would almost be as good as finally confirming the Standard Model. Note though that physics of today is well aware that the Higgs is only theoretical - and that wasn't the case with aether.

Ok, just in time for July 4th the Higgs boson has been declared a reality. I found a great explanation {for the layman like myself at least} for the "God Particle" in a local newspaper article. The explanation is attributed to Al Goshaw, professor of physics at Duke

" 'It behaves exactly like the Higgs boson is predicted to behave,' Goshaw said.

The Higgs boson is a force-carrying particle. Each of the four fundamental forces of nature is proposed to have such a particle.

One of these forces is the electromagnetic force. When two charged objects are brought close together, they interact by sending photons, also known as light particles, to each other.

When two heavy objects like the Earth and moon are brought close to each other, they interact with the gravitational force. The Higgs boson, if theories are correct, is the particle that transmits this force. The Higgs is to gravity as the photon is to the electromagnetic force. "

Read more here: http://www.charlotteobserver.com/2012/07/04/3362382/scientists-believe-they-have...

I did not think of the Higgs as the exchange particle for gravity. My understanding is that gravity as a field is supposed to have its own particle - the graviton.

Higgs is responsible for the presence manifestation of mass, not so much the interaction between massive objects or for the quality of resistance to force.

Maybe I have a mistaken understanding. Always a possibility.

ETA
struck presence to read manifestation. Maybe the existence of the quality of mass?

The newspaper article does not show that explanation as a direct quote from Professor Goshaw. Perhaps it is a reporters interpretation of an explanation. I like that the article is something close to what I can wrap my brain around.

Thanks for yours and any other posts that offer insight into the discovery. I was {an still am a bit} feeling quite the stupe for having only the vaguest notion of what is heralded as a monumental, evolutionary science discovery.

One of the USA broadcast stations had a short interview with Michio Kaku as he was two stepping down a hallway excitedly in his office building giving his take on the topic. He said the research "opens the door for finding other universes".

I think I read that one theory is that mass or gravity emanates from a parallel universe?

Don't take my comment as anything close to accurate. Some others will likely comment here to straighten us out.

#7 No problem - I doubt anyone would venture to say they have the definitive opinion on the topic! Besides I went to UNC Chapel Hill {something they are loathe to admit} and to make a slight correction to a Duke prof's statement would be something to cherish. ;-)

I found this quote in an article after an online search:

( While all of this took place a rock-climbing physicist from Harvard University - Lisa Randall - had been greatly troubled by one of our physical forces: gravity. Why was it that gravitational force was so comparatively weak, when compared with other physical forces? Though intuitively gravity seems rather strong - it fixes us to the planet, for instance - it is in fact surprisingly weak. Despite the force of the sum of the Earth's gravitation pull on us, we are still able to move, for instance. Gravity's force can be overcome extremely simply, by using a weak magnet. A metallic object such as a pin can be lifted out of gravity's pull very simply using such a magnet. Why is this? Could it be that its force is being dissipated in some way? Could gravity be somehow 'leaking' into, for instance, the Eleventh Dimension? When Lisa Randall carried out experiments to check the validity of this hypothesis, her calculations wouldn't compute. Then, she started to consider a bizarre proposition. Instead of gravity leaking from our universe into one of our more unusual dimensions, could gravity be instead originate from a different membrane, elsewhere, and be leaking into our universe? In effect, could gravity come from a parallel universe? When Lisa Randall redid her calculations using an alternative membrane as a point of origin for gravity, she resolved her equations. The weakness of gravity could at last be explained, but only by introducing the idea of a parallel universe

I'm sure Goshaw knows what he's talking about, though I think his statement is too strong. He's referring to predictions made by the standard model of particle physics, formulated in the 1960s. Many other (though far from all) varieties of non-standard models make similar predictions, and measurements of many properties of the particle discovered last week are not yet accurate enough to distinguish between the various possibilities. There is not yet any significant disagreement with the predictions of the standard model, but claiming "exact" confirmation may be misleading when even some of the cleanest measurements have uncertainties of ~25%.

Michio Kaku, on the other hand, is a well-known nutball, a status reinforced every time he makes a comment like that. Also, a good rule of thumb is that any writers who refer to the Higgs boson as a "god particle" do not have the slightest idea what they're writing about. You can stop reading immediately upon seeing those words.

As Richard noted, the fourth paragraph quoted in 4 is completely wrong, while the second and third are irrelevant. For reliable information about the Higgs (and much more) and geared for the general public, I strongly recommend Matt Strassler's Web site. A good place to start may be his recent summary of "Why the Higgs Particle Matters".

I would not describe the Higgs as "responsible for the manifestation of mass" as in 5; I think that also is too strong a statement. In order for the known elementary particles to possess the masses we observe them to have, a Higgs field (or multiple Higgs fields) must exist. But it is perfectly possible for there to be different types of as-yet-undiscovered elementary particles (possibly including those that form the dark matter of the universe) that can be massive without any need for a Higgs.

Regarding the quote about parallel universes, I have a reasonable idea what it's trying to explain, though it does so in language so fanciful as to be nearly meaningless. You might want to go to the source and check out Lisa Randall's popular physics book Warped Passages.

Finally, going back to the first post in this thread, one way the Higgs field differs from the classical aether is that you are always at rest with respect to the Higgs field, no matter how you are moving. Strassler briefly touches on this point in a comment on his "Higgs FAQ".

dashaich,

Thanks for the link to Strassler. Not the first time you have pointed me to his blog, but I needed the reminder.

It had not even crossed my mind that dark matter might interact differently.

Strassler's list of questions regarding all that remains to be understood put this discovery in the context of even greater excitement over discoveries to come.

Now to diverge a bit:

From Strassler's Higgs FAQ

A field is something that
1.is present everywhere in space and time,
2.can be, on average, zero or not zero, and
3.can have waves in it.
4.And if it is a quantum field, its waves are made from particles.

.........

A quantum field’s waves cannot be of arbitrary intensity. The least-intense possible wave that a field can have is called a particle, and it often behave in rough accordance with your intuitive notion of “particle”, moving in a straight line and bouncing indivisibly off of things, etc., which is why we give it that name.

Two requested confirmations:

1. The old dichotomy of sometimes particle and sometimes wave is then actually phrasing the question wrong. A particle is the quantum of a wave. A wave in a field is not continuous, it is quantized, and that unit we can call a particle, for lack of a better word.

2. Faraday's intuition about his field description of electricity was remarkably dead on descriptive about nature. I had always thought it was a way to understand things, but more profoundly, it is the way of things.

#9 post's recommended Matt Strassler's Web site is a great place! Richard B also pointed that way in other topics. I just had a chance to browse the site a bit for the first time. It looks like there is a danger of becoming a, head nodding yes, zombie acolyte disciple of Srassler if not careful however ;-)

I'm not sure about the "least-intense possible wave is called a particle". If by intensity he means energy and for example the particle is an electron surely he can't mean that an electron is an electron only when it's in its ground state?

13> I'm not sure about the "least-intense possible wave is called a particle".

He's only talking about particles that are quantums of a field, like a photon is the quantum of the electromagnetic field (I'm sure I'm using quantum wrong but I don't know how else to say it). A photon represents the smallest amount of electromagnetic energy that exists (although it can be a high-energy or low-energy photon depending on it's wavelength, so Strassler must mean something else by intensity in that statement).

Yes, intensity and energy are distinct concepts -- this was one of the contributions Einstein made in his "miracle year", in the context of the photoelectric effect (the work for which he was awarded the Nobel Prize). Briefly stated, the intensity of a wave depends on its amplitude, while the energy of a wave depends on its frequency (or equivalently its wavelength). A consequence of the identification of the electron as the least-intense possible wave in the electron field is that all electrons have the same mass.

More intense fluctuations in the electron field represent either multiple electrons or "virtual particles" (a problematic term since such fluctuations don't possess the properties we associate with "particles": they don't have a well-defined mass and they don't propagate or interact in a particle-like way). I would avoid referring to virtual particles as "excited states" to be contrasted with the "ground state" of the electron itself; that terminology is better-suited to composite (non-elementary) particles and fields, such as hadrons or atoms. An electron in an atom is always the same particle regardless of whether the atom is in its ground state or an excited state.

#12: It looks like there is a danger of becoming a, head nodding yes, zombie acolyte disciple of Srassler if not careful however ;-)

There are worse fates. One of the reasons I recommend that site so strongly is that Strassler makes a point of explaining the mainstream consensus in his pedagogical articles. So you won't really become his personal zombie, but rather a zombie of modern physics in general.

Regarding the particle--wave dichotomy mentioned in #11, this is a somewhat different issue than the relation between particles and fields... long story -- see here.

"Strassler makes a point of explaining the mainstream consensus "

Thanks for taking the time to point that out and the explanatory links. I have Strassler's site bookmarked as a reference. It would have taken me hours to ferret out reliable resources.

I happened to be near a library today and picked up the book Massive: The Missing Particle That Sparked the Greatest Hunt in Science by Ian Sample. It was published in 2010, well before the confirmation of Higgs Boson of course, but I noticed it on the shelf and thought it might be enlightening.

.......A little later. I just scanned the first few pages and Higgs was working at UNC chapel Hill in 1965 when he published his "first major paper on the origin of mass"!!

I finished Massive: The MIssing Particle and it was informative to me, a layman. It takes us to the start up of the Large Collider that got the HIggs particle results.

I am confused by stuff like a "top quark" weighing as much a gold atom. I thought it was a component of a proton, neutron etc. guess I will have to look that up.

Near the end of the book the author, not a physicist, writes about Higgs to dark matter etc. reminiscent of Kaku's comment above in #6.

"...Some physicists believe that our own Higgs field will be tenuously linked to other Higgs fields that give mass to particles in the hidden" {dark matter} "world.........The Higgs field is unique in being able to do this, for several reasons. One crucial feature that sets the Higgs field apart from all others is that it is a scalar field. This means that only the Higgs field looks the same from every direction. A second feature is that the HIggs field, and so its associated particle, permeates all of space. These two features make the Higgs field incredibly sensitive to tiny fluctuations in energy that might ripple over from the hidden world."

"...The effect would show up in the LHC's detectors as a sudden burst of particle tracks that seem to come from nowhere. Spotting tracks like this would allow scientists, working backward, to build up an idea of the kinds of hidden-world particles the Hisggs boson must have decayed into."

Currently reading The God Particle: If the Universe Is the Answer, What Is the Question? written in 1994 when the Superconducting Super Collider in Texas was set to lead the search for the Higgs boson and A Hole in Texas: A Novel (2004) about the SSC's cancellation and subsequent discovery of the Higgs boson by the Chinese. Both timely and ripping yarns.

#19 In Massive Ian mentions that President Clinton, if memory serves, made a decision between money for the ISS space station or the Texas Super Collider, both with centers located in Texas. He went with the ISS and later on balanced the budget. I think he made a good call.

There are six kinds of quarks, whose masses span a huge range from ~2 MeV (four times the mass of the electron) to almost 180,000 MeV (about the mass of a gold atom). Protons and neutrons are predominantly composed of gluons and the lightest quarks, called "up" (~2 MeV) and "down" (~5 MeV), with some non-negligible contributions from the "strange" quark (~96 MeV) and even the "charm" quark (~1250 MeV).

I strongly suspect something got garbled on its way into Sample's discussion of dark matter. Dark matter is a topic on the periphery of my research, but I am far more familiar with models in which dark matter particles interact with the actual Higgs field itself, rather than additional "dark Higgs" fields that mix with the usual one. I'm sure there are some models of the latter sort (in the field of dark matter there seem to be models of every conceivable sort), but I don't think they merit the amount of advertisement that Sample gives them. Moreover, trying to connect this to Kaku's balderdash involves considering the dominant portion of the matter surrounding us as a parallel universe, which I don't think is appropriate.

On the scale of the federal budget, the SSC was inconsequential, and none of the funds saved by abandoning it part-built went to any other science project. I suspect "science project" here includes the ISS, even though it's scientifically useless, an issue discussed by Robert Park's Voodoo Science: The Road from Foolishness to Fraud in addition to the article linked in the previous sentence:

The International Space Station was partly responsible for the cancellation of the SSC. Both came up for a crucial vote in Congress in 1993. Because the Space Station would be managed from Houston, both were seen as Texas projects. After promising active support for the SSC, in 1993 the Clinton administration decided that it could only support one large technological project in Texas, and it chose the Space Station. Members of Congress were hazy about the difference. At a hearing before a House committee, I heard a congressman say that he could see how the Space Station would help us to learn about the universe, but he couldn’t understand that about the SSC. I could have cried. As I later wrote, the Space Station had the great advantage that it cost about ten times more than the SSC, so that NASA could spread contracts for its development over many states. Perhaps if the SSC had cost more, it would not have been canceled.

It makes me sick to my stomach that the US did not move forward with the collider. It is like a conscious decision to abdicate leadership.

#21 Thanks for the info on the ISS vs SCC projects. Ian's book gave the impression it was a "political" decision in that government did not want to fund both and Texas was the home state of the former president Bush. The timeline he mentions is two days before the decision to build the SCC in Texas was made Bush the 1st was elected Pres.. Then after 2 billion was spent and projected costs escalated to 11 billion Clinton canceled the project.

Ian also had a caveat that Texas was a great place geologically because of a huge "flat" chalk bed to tunnel through.

I have read the opinion that the ISS has in reality had fewer "research" results than expected, when costs are considered, but to me it seems to promote a {all join hands now ;-) } "global unity" by reaching the imaginations of more people perhaps than the SCC would have.

I will be the first to admit my opinion may be influenced by the inability to intellectually appreciate the magnitude of the Higgs size collider's contributions to mankind. Ian mentioned that when the electron was first discovered it was held to be of no applicable significance. {This was before we used electricity}

The article linked : The Crisis of Big Science May 10, 2012 by Steven Weinberg, is well written and concise -good stuff!

I think it also had to do with that we had international commitments to help build the ISS. To back out would have been a diplomatic fiasco.

Yes, it was all political. Both Space Station Freedom and the SSC were conceived in the Cold War, to compete with the Soviet Union. This was the sole purpose of the space station (I don't think anybody expected any research results to speak of), and the reason the U.S. tried to "go it alone" with the SSC. As #24 notes, the space station made a more graceful transition to the post-Cold War environment, merging with Mir-2 and the European Columbus program. A Japanese colleague of mine was telling me just a few weeks ago that the Japanese government set aside $1 ($2?) billion in 1993 to contribute to the SSC if they were asked to do so by the Clinton administration; they weren't. Probably this has something to do with the SSC being managed by the Department of Energy rather than NASA: the DOE also manages the US nuclear stockpile and (especially during and shortly after Cold War) tended to be less receptive to foreign collaboration.

The SSC's main challenges were problems of perception -- PR, in other words. The perception of mismanagement and cost overruns were far more severe than the reality. You'll often hear statements that the projected cost ballooned from $4 billion in 1987 to $11--12 billion in 1993. This looks like a 300% increase, but in order to get it you have to ignore inflation; compare the lower limit of the initial cost estimate with the upper limit of the final cost estimate; and include the detectors in the final cost but only the accelerator itself in the initial cost. The accelerator was going over budget even if you do the accounting properly, but only by 10--20%, not 300%. Unfortunately, it's been many years since I read the very interesting article that laid out this issue, and I don't know if I could find it again if I tried. (Also, I was told at that discussion a few weeks ago that only this budget overrun forced the project to go through a full re-approval process that ended up killing it; I'm not sure whether I completely buy that, given the capriciousness of the normal U.S. budget process.)

In a similar vein, the perception that the SSC was being built in Texas for political reasons also did serious damage, even though Waxahachie was in fact a good site geologically. The fact that the Speaker of the House in 1987 was a Texan (Jim Wright, whose district was within commuting distance of the SSC site) was probably more significant than Bush's connection to the state. In 1993 the Speaker of the House was Tom Foley, from Spokane, Washington.

As an aside, the Deep Underground Science and Engineering Laboratory is currently having some similar problems with the perception that it was sited in South Dakota in order to win the support of former Senate majority leader Tom Daschle. This is despite the fact that the site was chosen two and a half years after Daschle left office. I've heard claims that this contributed to the plans for that site being scrapped this spring, though I am somewhat skeptical.

Finally, there was the perception that the funds being spent on the SSC would produce more "bang for the buck" by being redirected to other projects. I wasn't around at the time, but I'm told it was obvious well in advance that if the SSC were cancelled its funding wouldn't go to other areas of science, but would vanish back into the discretionary pot. As I mentioned in my previous post, this is exactly what happened.

Regarding the "conscious decision to abdicate leadership" mentioned by #22, this was appreciated at the time. On 16 June 1993, President Clinton wrote:

Abandoning the SSC at this point would signal that the United States is compromising its position of leadership in basic science—a position unquestioned for generations.

What's troubling is that this is just one piece in a larger trend of the U.S. abandoning leadership in all areas of science, from basic research to applied technology. It's not just a high-energy physics problem, but in high-energy physics we're faced with the prospect of the U.S. giving up even the junior-partner role it currently plays. This spring I saw a depressing presentation by the Associate Director of the DOE's Office of High Energy Physics, which warned that the U.S. might not participate in upgrades to the LHC planned for around 2018. In addition, while the U.S. is currently maintaining "VERY low-level GDE involvement" (emphasis in the original) with the Global Design Effort for an international linear collider to succeed the LHC in the future (no sooner than the 2020s), it has no interest in hosting the linear collider, and may not even participate in that project at all. This presentation may even be optimistic -- it didn't contain any warning that the Long Baseline Neutrino Experiment (LBNE) at the Deep Underground Science and Engineering Laboratory was in trouble; plans for LBNE were scrapped about a week later. (If you want to check out those slides, HEPAP=High Energy Physics Advisory Panel, P5=Particle Physics Project Prioritization Panel, and DPF=Division of Particles and Fields of the American Physical Society.)

(Edit to add links)

daschaich,

You are not helping my stomach feel better. But thanks for the info on plans for future research. Maybe some politician will have the sense to stand up and stand out, to raise this as an issue and a challenge.

I have some friends who quesion the massive investments in scientific research. They are not convinced with by the arguments that the costs are not especially large, relative to other budget items; nor that the long range return always exceeds the investment (though not always to the researcher, always to humanity); nor that the US should have leadership in the sciences if it expects to remain a world leader politically.

#26

The problem with research (and not necessarily big science) is that not every project delivers results. To non-science people that looks bad - they ask "why can't we just fund the projects that are successful. That do deliver results on which we can make money fast." As a result science funding may be cut, or go to very safe projects which are likely to deliver short-term exploitable results. Non-science people often don't realise that a negative finding is often as interesting and important as a positive finding.

No doubt. Michelson-Morley comes to mind as a successful failed experiment.

From an older astronomy book A short history of astronomy:

modern theories of light and electricity require space to be filled with an ether capable of transmitting certain waves; and although there is no direct evidence that it in any way affects the motions of earth or planets, it is difficult to imagine a medium so different from all know forms of ordinary matter as to offer no resistance to a body moving through it.

How things have changed.

And how much more will they change.

Rutherford - Hey let's shoot some of this stuff at some gold and see what happens.

The following quote from daschaich's article The Crisis of Big Science May 10, 2012 by Steven Weinberg prompted me to go off track and search some government costs. { I think the Afghanistan war was unavoidable, the first Iraq war caused by bad politics, second Iraq war a mistake in escalation IMOHO.}

"...We had better not try to defend science by attacking spending on these other needs. We would lose, and would deserve to lose. Some years ago I found myself at dinner with a member of the Appropriations Committee of the Texas House of Representatives. I was impressed when she spoke eloquently about the need to spend money to improve higher education in Texas. What professor at a state university wouldn’t want to hear that? I naively asked what new source of revenue she would propose to tap. She answered, “Oh, no, I don’t want to raise taxes. We can take the money from health care.” This is not a position we should be in".

U.S. 2009 Monthly Spending in Iraq - $7.3 billion as of Oct 2009

From the Stars and Stripes
.."According to Defense Department figures, by the end of April the wars in Iraq and Afghanistan — including everything from personnel and equipment to training Iraqi and Afghan security forces and deploying intelligence-gathering drones — had cost an average of $9.7 billion a month, with roughly two-thirds going to Afghanistan. That total is roughly the entire annual budget for the Environmental Protection Agency."

#29 and making gold into lead is going to be funded by whom? ;-)

#31

By "Hu", surely.

:-)

Once again, like most Threads on LT, this thread has veered.
Into politics this time, surprise, surprise.
At least not into "fundamentalistic" religion!
(Wow, one of the longest words I have ever spelled)

Hi, what happened to the Higgs field?
And thingys like that?
Like Physiks and Chemystry and things of importance?
Oh, a bit of Maths would'nt go astray either!

Your old curmudgeon,

Guido.

Ok I am reading parts of Strassler's website, still a bit confused as to where {"The third generation consists of the tau, the neutrino-3, the top quark and the bottom quark"} those big top quarks would live at - in atom nuclei bigger than a gold atom or were they present in the "big bang soup" and temporarily recreated when you bash stuff together?

::edit:: ok I got this quote from {the hated} wiki which helps a bit: "Because top quarks are very massive, large amounts of energy are needed to create one. The only way to achieve such high energies is through high energy collisions. These occur naturally in the Earth's upper atmosphere as cosmic rays collide with particles in the air, or can be created in a particle accelerator. As of 2011, the only operational accelerator that generates a beam of sufficient energy to produce top quarks is the Large Hadron Collider at CERN, with a center-of-mass energy of 7 TeV."

and to appease Guido, this quote from the inestimable fount of knowledge - Playboy magazine:

A physics professor was explaining a particularly complicated concept to his class when a premed student interrupted him.
"Why do we have to learn this stuff?" the young man blurted out.
"To save lives," the professor replied.
"How does physics save lives?" asked the smartass student.
"Physics saves lives," the professor said,
"because it keeps certain people out of medical school."

Probably a tired old joke. ;-)

The Higgs field gives elementary particles their mass, as a result the Higgs field is the source of mass for all objects.

What is mass?

There is gravitational and inertial mass. Gravity the attraction between massive objects resulting from their mass. Inertia the resistance from mass to an object's change in speed or direction of motion.

It is easy to visualize a field that would resist a change in direction or an increase in speed. But it might seem that a such a field would inherently bring a decrease in speed, by providing some resistance to the motion.

How does the Higgs field create the gravitational attraction between massive objects?

Dear DugsBooks,

I read "Playboy" to oggle at the nude women!

I was eventually surprised to find that the articles were written by 'erudite' authors, and that some of the greatest cartoonist contributed to that magazine.

But I agree, I can't get my brain aroung the 'triloghy' that appears in nature.

G.

There are a few problems in #35. First, gravity affects everything with energy, only one form of which is mass. (Remember that gravity bends light, which is massless.) Next, the Higgs field is required for electroweak gauge bosons and chiral fermions to be massive, but it is not the source of mass for all objects. In fact, "the link between the Higgs and mass is likely to be true only for the known elementary particles, and may not be true for other elementary particles yet to be discovered — and is not even true for the Higgs particle itself." The emphasis is in the original, which includes a longer discussion of why "any resemblance between the Higgs field and gravity is purely coincidental!"

With that in hand, the question "How does the Higgs field create the gravitational attraction between massive objects?" has a simple answer: It doesn't.

Finally, while it is easy to visualize a field that would resist a change in direction or an increase in speed, this is not how the Higgs field behaves: "Analogies which refer to the particle’s mass as having something to do with the field being like molasses, or a room full of people, are problematic analogies because they make it seem as though a particle must be moving in order to feel the effect of Higgs field, whereas in fact that is not the case."

Guido, I hope you appreciate the irony of posting about Playboy after complaining about off-topic posts on the recent history of hadron colliders -- I know I do.

Yep, Irony :-)

Hi Group and #37 in particular,

I hope you had the "equasions" (spl?) open on your desk when you said Finally, while it is easy to visualize a field that would resist a change in direction or an increase in speed, this is not how the Higgs...

I find it difficult, nay impossibe, to "visualize" a field. It is just a mathematical construct to me.
And I know I can't Visualize them at all.

ETA. I am not just a "smartarse". I do truely want to understand these difficult/complex concepts.

Ack, Hi Guido, my joke about physics was not an attempt at putting anyone in the role of the recalcitrant physics student.{if that is how it appeared}. It was just a joke I serendipitously came across and tried to squeeze in apropos of something. I am confused in that I thought all the products of particle colliders were "subatomic" particles smaller than what they started with! I also appreciate daschaich's attempts to enlighten me.

equations

#39
My son-in-law is one of the CERN physicists who has been searching for the Higgs boson and on 30 June, in his wedding reception speech, he announced the discovery of the Higgs boson would be announced later in the week.

In relation to your comment, I do truly want to understand these difficult/complex concepts.
, he would say "So do all the physicists in CERN".

Thanks #42, You have truely made my day :-)

G.

We aim to please. :-)

pgmcc,

Please pass our congratulations and appreciation to your son in law for his work.

We are fortunate to have some physicists here on LT, like daschaich, who take time to help with some questions.

#45 On Phil's behalf I say, Thank you!. I will pass on your regards.

My daugher is also a physicist and at times it's like being in an episode of "The Big Bang Theory". :-)

In my understanding the original concept of the Higgs boson had it giving mass only to other bosons (i.e gluons and W and Z bosons since the photon is massless). Later the concept was expanded to include fermions. Now because of indications that the Higgs discovered at CERN is not quite in agreement with the Standard Model people are talking about going back to the original conception and postulating a supersymmetric particle to give mass to fermions.

#39: I hope you had the "equasions" (spl?) open on your desk

I've been familiar with the equations for several years, but I was addressing a much simpler issue: particles' masses don't depend on their motion. (And, in a forum such as this, I make a conscious effort to avoid jargon, equations and other technical language, since I suspect it would not help my aim of communicating information.)

Fields are not necessarily so abstract. Look at a cup of coffee and you have visualized a field: a field is something that has a value at every point in a given region, such as the density or temperature of the coffee in that cup. If we were able to look closely enough to see that the coffee were actually a collection of various molecules, this description would break down, but on human scales it is completely legitimate. The main difficulty in shifting from the sorts of fields we work with every day to those describing elementary particles and forces is that the latter are governed by relativity and quantum mechanics. (There is also no indication that this description ever breaks down, but that's less important.)

#47: Gluons are also massless, and the original concept of the Higgs mechanism (by Brout, Englert, Guralnik, Hagen, Higgs and Kibble in alphabetical order, building on earlier work by Anderson and others) came from abstract consideration of what would happen if a symmetry broke spontaneously in the context of a relativistic gauge theory. (Unfortunately, this issue suffers from some of the worst jargon in particle physics.) It wasn't until a few years later that Weinberg applied this concept to the particular relativistic gauge theory that Glashow had earlier proposed as a model for W bosons and photon (the Z boson was a prediction of the model). Once that application had been made, the connection to elementary fermions was immediate -- Weinberg's paper is actually called "A Model of Leptons".

There is not yet any reliable indication that the particle discovered at CERN differs from the Higgs boson predicted by the standard model. Of course, this won't stop people from working on most of the many ideas for physics beyond the standard model (including supersymmetric scenarios) that they have been developing for the last several decades. Those models are now just more tightly constrained by the requirement that they accommodate a standard-model-Higgs-like boson with mass around 125 GeV. There is no need to go back to the original conception.

From what I've read (and admittedly the number of events observed is still too small to be fully determinative) the number of decays into tau particles is less than expected and the number of decays into photons are greater than predicted. I believe the thinking is that if the Higgs is not decaying into taus it is probably not giving them mass and that leaves the gate open for one of the supersymmetric Higgs particles to do so.

ATLAS measured the number of decays into photons to be a bit less than 1.8 standard deviations larger than the standard model predicts. For CMS, the excess is only 1.3 standard deviations. That is, both of these measurements are in agreement with the standard model prediction at the usual two-sigma level of uncertainty. The agreement with the standard model may actually be even better than that, since some standard model uncertainties may be underestimated (particularly those related to the strongly-interacting quantum effects through which the Higgs boson couples to the massless gluons on one side and the massless photons on the other).

The number of decays to taus is in even better agreement with the standard model, with overlapping uncertainties between the prediction and the measurements (or, in the language I used above, differences of 1 standard deviation or less). That is, these results are in complete agreement with the standard model prediction, albeit within fairly large uncertainties. The uncertainties are large because it is very hard to measure these decays to taus at a hadron collider, in large part since the taus themselves can decay to hadronic jets. I don't even recall seeing actual numbers for the tau rate in the ATLAS and CMS presentations at ICHEP, though these points are shown on some plots. The CMS plot actually shows a negative number of decays into taus, which gives you some indication of how reliable these results are at present...

In generic supersymmetric models you have (for anomaly cancellation among other reasons) an up-type Higgs field that couples to the up-type fermions and a down-type Higgs that couples to the down-type fermions. When you move from the flavor basis to the mass basis, I'm sure it's possible to fiddle with the model parameters so that the particle at 125 GeV has suppressed couplings to some or all of the fermions. You can do the same thing in other non-supersymmetric models with multiple Higgs fields.

In short, a tau-phobic Higgs is not unique to supersymmetry, is not required by supersymmetry, and is not yet motivated by the data. In the future there may be actual deviations from the predictions of the standard model, but trying to justify physics beyond the standard model with the current data is really grasping at straws.

My information on the decays came from the July 14th issue of New Scientist. I would be interested to know if you've read the article and if you think it's hype.

I don't have a subscription to New Scientist, so I can only see the titles and first few paragraphs of the articles in that issue. Most of that limited sample looks to be reasonably accurate, but there is definitely some hype, including the "Deviant decays hint at exotic physics" headline. Keep in mind that the press hypes whatever it can as a survival instinct, and tends to display a particularly poor grasp of probability and statistical significance.

They didn't report the differences in terms of standard deviations. They reported the tau decay as "a lot less than the 6% expected" and the photon decay as "one-and-a-half times the rate predicted".

I don't know how that compares to your data.

#53: They reported the tau decay as "a lot less than the 6% expected" and the photon decay as "one-and-a-half times the rate predicted".

Yes, both of those statements are incorrect, precisely because they didn't consider the uncertainties (the standard deviations). The uncertainties on the CMS photon decay rate are such that it is only known to be between 0.7 to 2.4 times the standard model prediction, at the two-sigma level (the 95% confidence level). 1.5 times the rate is indeed the "central value" of this range, but at present the experiment simply can't tell whether the rate is larger or smaller than the prediction!

The situation is similar for the taus, except that the uncertainties are much larger: the experiments' results are consistent with a tau rate of anywhere from zero to roughly 1.5--4 times the prediction (1.5x for CMS, 4x for ATLAS).

Below I include the overall summary plots from the presentations I linked above (conveniently posted online by this blog). These plots show the ratio of the measured rate compared to the standard model prediction: 1 is agreement with the prediction, 0 is no discernible signal at all, and negative values are physically nonsensical, but provide some information about the current reliability of the results. Note that ATLAS has drawn a vertical line at the standard model prediction (not at the average of their results, 1.2±0.3), while CMS has drawn theirs at the average of their results, roughly 0.8±0.2 (not at the standard model prediction).

To correctly interpret these plots, note that the error bars shown on the data points correspond to one standard deviation, or the 68% confidence level. So, if the standard model prediction is correct, roughly one third of the data points should disagree with the prediction simply due to statistical fluctuations. This rule of thumb is widely used as a simple sanity check to consider whether error bars might have been under- or over-estimated.

Thank you. New Scientist actually gave the second chart but didn't note that the scale at the bottom was in standard deviations nor did it give your explanation of the significance of zero and negative values which rather alters the whole thing.

Quick clarification that I should have anticipated: the horizontal scale in each plot is the ratio of the measured cross section to that predicted for the standard model Higgs particle ("SMH"). (CMS writes out the ratio, ATLAS just calls it mu.) The cross section is a measure of how many events there are for a given amount of data (above I called it a "rate"), and it is designated by the same Greek letter (sigma) used to refer to standard deviations. The standard deviations themselves are given by the sizes of the error bars on the points.

Possibly of interest: I just read in Physics Today a fairly glowing review of The Infinity Puzzle by Frank Close. The reviewer praises the book for going into more detail than Ian Sample's Massive, which was mentioned in #17, #18 and #20.

Edit for clarity/grammar.

#57 Thanks for the suggestion dasch. I am still interested in the topic but not able to pursue it at fast pace {gotta work & pay bills}. A leisurely read when I have time is probably my best bet.

I went to a {free} lecture by Sean Carroll who was pushing his new book The Particle at the End of the Universe last week. He did a great one hour more or less presentation with projected illustrations about the Higgs boson and explained he hung out at CERN for a while during the hoopla. I did not buy a copy of the book {my stock in apple has gone from way + to way -} but he was signing copies.

The lecture was concise and hit all the high notes evidently; the short line graph with a lump in it that indicates the higgs boson, photos of the accelerator, and brought everyone up on what is happening now at CERN with an upgrade of the accelerator. My favorite part was his making a little more clear the the Higgs field is always there and when a lot of energy is added to it the Higgs boson is the, very ephemeral, result. I had wondered why the sum of bashing two protons together seemed to be more than the parts as related to the energy level of the higgs. He also related that this is the case for other particles but I forget the details.

He mentioned a "next step" might be an electron accelerator which would have the advantage of fewer particles to sift through while looking for exotic phenomenon after bashing them together - because their mass is so much less than a proton.

Link to Sean Carroll's website:
http://preposterousuniverse.com/particle/

Here is a longer talk about the 'Higgs Field' by Carroll

Thanks guido, that is the same lecture I saw more or less. He has a question/ answer session after the presentation. I am on the waiting list at the library for the book - I hope it does not increase my overdue fees.

How quickly the world changes :-)

I recently received Penrose's The Road to reality He briefly mentions it (Higgs) on one page but does say "...the full detail of this remarkable and ingenious body of ideas must, unfortunalely, remain outside the scope of this book...".

The book is copyrighted 2004. Not yet 10 years old.

Dear Group.

I quickly re-perused this thread and hope you might find This lecture, on the 'Higgs...', by Susskind usefull. I have mentioned another lecture by Sussking on another thread in this Science! group.

I would like it, if the LT "workers in the field (not a QFT type field :-)" would comment. I understand that it is 'impossible' to visualize these concepts and that they can/should only be 'seen' through mathematics.

But...but...I can only try. And I do like Susskind as a lecturer, for trying to show, a non dumbed down, 'physics' to a layman.

Guido.

I just ran across this short but very interesting article by Michio Kaku "Whats Next After the Higgs?".

A couple of quotes from the article: But 23% of the universe is made of Dark Matter, and 73% is made of Dark Energy, and we physicists are clueless to understand what they are. So most of the universe, 96% in fact, is beyond our present day understanding. (So all high school textbooks which say that the universe is mainly made of atoms are wrong and have to be revised.)

Next, we hope to find evidence of Dark Matter with the Large Hadron Collider, which may be a higher resonance of the string. And beyond that, we hope to find evidence of parallel universes and higher dimensions predicted by string theory.

#63 guido, I finally had a chance to view your link to Susskind {they don't call me lightnin for nothin!} and was surprised that mass can be gained in different ways. Afraid I might have nodded here and there in the one hour talk but he did a good job of explaining about as much as I can understand about the subject.

edited to make better sense