# Explanation of the Higgs Field?

1. Jul 13, 2009

### um0123

I want to understand the higgs field more, but all the explanations i read i only slightly understand. Even that explanation of the celebrity walking into a room just made me more confused.
Why does the higgs field gives objects mass? and how is the higgs field created? I want to know more but i just cant seem to understand it.
Any response is greatly appreciated but keep in mind i am only 16 and havent had any courses on particle physics (besides my late night google sessions )

2. Jul 13, 2009

### malawi_glenn

Ok, it's gonna be tough to explain HOW and why it gives masses to some of the particles without the fancy math behind it (probably impossible). The short answer is that it gives mass to the W and Z bosons by (mathematically) giving mass terms to the "Lagrangian" (the physical formula which contains expressions for the kinetic and potential energies for all the particles in the standard model). We can not have these "mass terms" without the Higgs mechanism and the Higgs field - the Lagrangian will not respect some of the most important symmetries that we know of. But with this field and this mechanism (spontaneous symmetry breaking) we can mathematically generate the terms we need to have massive particles in the Lagrangian AND respect this symmetry.

Now that was the best, non-mathematical, explanation I can give - that one needs math to see "how and why", maybe not so much of a comfort. I actually started to think about particle physics in my 3rd year of university studies of physics, and I was stunned of the Higgs Mechanism, I did not understand A SINGLE thing LOL but that encouraged me to search for and study the math and physics necessary - and now I can derive the Higgs Mechanism almost in my sleep, It took me 2years to learn more math and physics besides what I already knew.

So I really encourage you to study this to be seen from the eyes of a physicsts - we speak and think of things mainly in math - so our analogies and explanations can be quite anti-logical and confusing sometimes, so I refuse to give one of those "popular" physics explanations which exists out there.

Here is another explanation I recently gave to a guy who perhaps is a bit older than you but he has read many popular science books https://www.physicsforums.com/showpost.php?p=2268865&postcount=13

Here you can read about the Lagrangian, I think you are familiar with Newtons equations (?) http://en.wikipedia.org/wiki/Lagrangian_mechanics

Here you can find some explanations of quantum field theory:
(contains many errors though, but you can at least get some of the ideas)

And here is one of the best explanations (in math) of the higgs mechanism:
http://arxiv.org/PS_cache/hep-ph/pdf/0001/0001283v1.pdf

In order to understand things, one very often need the appropriate background and training, so don't give up!

3. Jul 13, 2009

### um0123

Thanks for the info, it was really helpful. I understand it may be hard to explain without mathematics. I usually only asked for non-mathematic responses because i didnt want to waste peoples time, considering i only have advanced algebra under my belt, i probably wouldn't understand any of the stuff you guys are saying. But some things can be explained non-mathematicly such as color charge (even though that has a lot of math to it) it can be explained without math by not going to far into the rabbit hole.

i know the basic concept of Lagrangian phormula, but i would like to know more. I have done some reading on the Quantum Chromodynamic Langrangian and i find it quite interesting. But i think i might be biting off more than i can chew.

I would love to learn more about this so thank you for the links and i intend to do some research. Since 8th grade i wanted to be a scientist and since 9th i wanted to be a particle physicist. So i started by reading on special and general relativity. While special relavity was easy enough to understand without math, general relativity - although i understood it - i felt i was not going deep enough to fully understand, that is what i feel when i try to research this stuff, it uses things like differentials, integrals, etc. and i just dont understand it yet.

Question Time:
May i ask which field of physics you specialize in?
How much mathematical and knowledge do i need before i can start to make sense of this kind of stuff?

Last edited: Jul 13, 2009
4. Jul 13, 2009

### malawi_glenn

Sometimes non mathematical explanations is not possible.

I am specialized in elementary particle phemenology, I have just started my phd studies - I do simulations for LHC experiments and astroparticle stuff. So it is a combination of theory and experiment one can say.

You need at least on full academic year at a unversity, plus some extra classes in group theory and stuff like that which is often not included in standard physics-program curriculum.

here is a good starter for you after you have done at least the first math year and the first physics year, you can have a look at it now and then go back to it each 6months or so.

http://arxiv.org/abs/0810.3328

Then you of course need a solid ground in classical and basic quantum mechanics and all that kinda stuff, 2years approx. if you follow the standard physics curriculum.

5. Jul 13, 2009

### um0123

Sounds really interesting

Wow, so i guess that means its gonna be a while before i can start to immerse myself in this.

Thanks for the link, ill add it to the rest. Do they teach quantum mechanics to undergrads? or would that be impossibly hard? Also what kind of math is involved, calculus obviously but is there something above calculus?

6. Jul 13, 2009

### diazona

Not impossibly hard at all - you need to know about complex numbers, of course, and linear algebra (the math of vectors and matrices) but that's about it, at least to get started. Obviously as you get deeper and deeper into QM you run across applications for more and more sophisticated math. At a lot of the colleges I'm familiar with, introductory quantum mechanics is a sophomore-level class. (I hear that at other colleges it's a senior-level class but I'm not sure whether that's the norm)

7. Jul 13, 2009

### um0123

I see, thanks for the info. its much appreciated!

But when you say sophomore year do you mean undergraduate or grad school? Cause if its graduate school i have a long long time to prepare, if its undergrad ill be there in 4 years and cant wait.

8. Jul 13, 2009

### Civilized

In the universities I am familiar with, there is usually a undergraduate sophomore level QM that is focused on the results (solutions) rather than the theory behind QM. Then the senior level course introduces the theoretical setting of QM, and shows how to calculate the solutions that you worked with as a sophomore. Then in the first year of grad school you do "Intro to QM" which is the full blown version that includes the parts of QM that almost all physicists use. After that the QM classes become more specialized e.g. quantum computing, solid state physics, particle theory, etc.

9. Jul 13, 2009

### diazona

I'm talking about undergrad. I don't think people usually apply the terms "freshman"/"sophomore" etc. to graduate students - normally it's "first-year," "second-year," etc.

10. Jul 13, 2009

### um0123

Thanks for the reply, i cant wait to learn this stuff, its so fascinating!

I see, thanks for the info.

This may be a little over the line so feel free not to respond but, are you guy all like super smart 4.0 students? After two years of high school i only have a 3.2 average, mainly due to laziness, but im trying to get my work ethic up.

11. Jul 14, 2009

### diazona

Well, I had a 3.3 departmental average in college... but the numbers don't tell you that much. A 3.2 at one school might be equivalent to a 4.0 at another.

12. Jul 14, 2009

### DrFaustus

um0123 -> Will try to give you the simplest and most intuitive explanation I can think of without any maths, Lagrangians or equations.

First you have to realize that quantum fields are not just "particle physics", even though that's how they are most frequently used. For example, a very hot gas of relativistic particles can be described by a quantum field. And more generally, quantum fields are used to describe matter and its interactions. So, roughly speaking: "quantum field = matter".

How do we think and what is mass? One way to understand it is to say that mass is that physical property of matter that opposes to a change of it's motion. That is, if an object is standing still and it's "very difficult" to move it (ignoring friction, like in outer space), it's because it's very massive. if, on the other hand, you can move an object just by "pinging" it, it's because it has small mass.

Finally, think about yourself running in air and in water. It's easier for you to change your running velocity in air than in water. And the faster you go, the more difficult would be to increase your speed. So you could (very heuristically and not really correct) say that in water you have "a mass that depends on speed". And in particular, such "mass" will increase. In other words, your mass "increases as you move through water".

And now let's put it all together. Think of all the elementary particles as being massless but propagating through some "medium" (the Higgs fields, that is matter described by the Higgs quantum field) which increases their mass. At least of some of them - the ones that do interact with that matter, the Higgs field. The photon does not interact with the Higgs matter/field and is hence massless.

As for the famous person walking in a room, if the room was empty (no Higgs field), he'd be able to walk with no impediment. But if the room is full of people, they will want to talk to the him slowing him down and, most importantly, making it more difficult for him to regain his original velocity - change his current velocity (the famous person has "acquired a mass").

Makes sense?

13. Jul 14, 2009

### um0123

That took me a while to read, i had to read over part of it a couple times, but i think i get it. I bet it makes a lot more sense and is easier to explain using math. Im sure there is more for me to learn but as everyone stated above some things cant be explained non-mathematically, so i am just gonna have to wait.. Until then im gonna keep learning what i can. Thanks for the response.