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Higgs Field: Perfectly Static Particle is Massless?

by Islam Hassan
Tags: field, higgs, massless, particle, perfectly, static
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Islam Hassan
#1
Nov24-12, 06:25 AM
P: 149
Like the question says: if a particle is perfectly static with respect to the Higgs field, can we still define mass or is mass then irrelevant?

On another note, (and if I am not mistaken) why does mass not vary with a particle's speed with respect to the Higgs field?


IH
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mfb
#2
Nov24-12, 08:37 AM
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Physics is the same in all inertial frames. There is no "perfectly static with respect to the Higgs field".
Every particle has the same mass, just given by its type and independent of its velocity relative to anything else.
Bill_K
#3
Nov24-12, 09:09 AM
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... and the Higgs field itself is the same in all inertial frames. It's a scalar field, uniform in time and space, and looks exactly the same to all observers no matter what their velocity.

The_Duck
#4
Nov24-12, 08:00 PM
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Higgs Field: Perfectly Static Particle is Massless?

Quote Quote by Islam Hassan View Post
Like the question says: if a particle is perfectly static with respect to the Higgs field, can we still define mass or is mass then irrelevant?

On another note, (and if I am not mistaken) why does mass not vary with a particle's speed with respect to the Higgs field?
You are probably thinking of the analogy that the Higgs field is like "molasses" which slows down moving particles, making them act as if they had mass.

The problem is that this is a very poor analogy. As you have noted, it suggests that the particle's mass should depend on its speed, which isn't true.
Islam Hassan
#5
Nov25-12, 03:48 AM
P: 149
Quote Quote by The_Duck View Post
You are probably thinking of the analogy that the Higgs field is like "molasses" which slows down moving particles, making them act as if they had mass.

The problem is that this is a very poor analogy. As you have noted, it suggests that the particle's mass should depend on its speed, which isn't true.
Yes, exactly, that is what prompted my question. If the molasses thing is a very poor analogy, then I guess I really don't understand the basics of the Higgs mechanism. Why do physicists keep using this analogy then? About time they should stop, no?

The problem is that there are so many poor analogies used by physicists to explain certain phenomena of non-classical physics, like the universe-with-no-center-expanding-on-a-balloon surface, an object's mass increasing with its relative speed, etc. How about some high-quality analogies for a change...


IH
tiny-tim
#6
Nov25-12, 04:19 AM
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Hi Islam!
Quote Quote by Islam Hassan View Post
Yes, exactly, that is what prompted my question. If the molasses thing is a very poor analogy, then I guess I really don't understand the basics of the Higgs mechanism.
i think a better analogy is to imagine space filled with velcro, and each particle having a coat of different densities of velcro

mass is resistance to movement (ie the more mass it has, the more force is needed to move it)

so stationary particles aren't affected by the velcro at all, but the heavily-coated particles feel a lot more resistance when they do move, and need to be pushed harder to achieve the same change in speed
Islam Hassan
#7
Nov25-12, 06:11 AM
P: 149
Quote Quote by tiny-tim View Post
so stationary particles aren't affected by the velcro at all, but the heavily-coated particles feel a lot more resistance when they do move, and need to be pushed harder to achieve the same change in speed

Hi there Tim :); well your comment brings me back to the original question: if the particle is stationary, can one talk of/define mass at all? I recall reading somewhere that electron for example 'collide' with the Higgs every 10^-17 cm on average, so if the electron was somehow stopped between 'collissions', can we talk of mass?


IH
Bill_K
#8
Nov25-12, 07:13 AM
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well your comment brings me back to the original question: if the particle is stationary, can one talk of/define mass at all?
IH, We've answered this for you several times. The mass of a particle is independent of its velocity.
I recall reading somewhere that electron for example 'collide' with the Higgs every 10^-17 cm on average
You misunderstood. In the first place it's the Higgs FIELD that is involved with particle masses. The Higgs field is uniform everywhere and doesn't need to be collided with!

The 10-17 cm is a reference to the Higgs BOSON. This is the distance that a virtual Higgs boson can travel before it is reabsorbed. (the Compton wavelength that corresponds to 125 GeV)
mfb
#9
Nov25-12, 07:55 AM
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Quote Quote by Islam Hassan View Post
The problem is that there are so many poor analogies used by physicists to explain certain phenomena of non-classical physics, like the universe-with-no-center-expanding-on-a-balloon surface, an object's mass increasing with its relative speed, etc. How about some high-quality analogies for a change...
Possible reasons:
- nobody found a better analogy of similar complexity yet
- the analogy is fine, but someone (usually not a scientist) used it where it is not appropriate

I think the balloon analogy is an example of a very good analogy.
Relativistic mass is a bad concept.
Vanadium 50
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Nov25-12, 08:31 AM
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Quote Quote by Islam Hassan View Post
How about some high-quality analogies for a change...
This is perilously close to "I don't want to put the effort into understanding this in detail - and it's your fault!"

It is said that a translation is like a mistress - either beautiful and unfaithful, or faithful but not beautiful. Analogies are the same way: they can be simple, they can be accurate, but usually they cannot be both.
Islam Hassan
#11
Nov26-12, 06:18 AM
P: 149
Quote Quote by Vanadium 50 View Post
This is perilously close to "I don't want to put the effort into understanding this in detail - and it's your fault!"

It is said that a translation is like a mistress - either beautiful and unfaithful, or faithful but not beautiful. Analogies are the same way: they can be simple, they can be accurate, but usually they cannot be both.

I understand your argument and can tell you that as a layman I have devoted much time trying to understand many phenomena in non-classical physics; sometimes quantitatively (SR and QM especially), sometimes not.

In some cases, as with the Higgs field/particle, common lay analogies are my starting point; this may in retrospect not be an appropriate approach, I grant you that. The issue I have however is that these lay analogies don't come with any type of qualification. They are simplified and therefore appear intuitive when often they are not. I am not against analogies, be they good or bad, so long as I am simultaneously aware of their (sometimes significant) limits.

I understand that physicists -like any other profession- enjoy informing the public of their very considerable scientific achievements. Simply, I don't think that adding a dose of qualification (call it realism...) to lay analogies would detract from our fascination with physics.


IH
Islam Hassan
#12
Nov26-12, 06:31 AM
P: 149
Quote Quote by Bill_K View Post
IH, We've answered this for you several times. The mass of a particle is independent of its velocity.

You misunderstood. In the first place it's the Higgs FIELD that is involved with particle masses. The Higgs field is uniform everywhere and doesn't need to be collided with!

The 10-17 cm is a reference to the Higgs BOSON. This is the distance that a virtual Higgs boson can travel before it is reabsorbed. (the Compton wavelength that corresponds to 125 GeV)

My reference is at 37:05 mins on this IAS lecture by N Arkani-Hamed:

http://www.youtube.com/watch?v=weGgGkt7_48

He talks of an electron moving around and 'banging into' the Higgs field 'condensate' every 10^-17cm. This I trust is equivalent to your statement re this being the distance that virtual Higgs bosons travel.


IH
mfb
#13
Nov26-12, 08:07 AM
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Quote Quote by Islam Hassan View Post
Simply, I don't think that adding a dose of qualification (call it realism...) to lay analogies would detract from our fascination with physics.
There is some limit how much you can explain with simple analogies - otherwise you could use this analogy as scientific theory. If you want to go beyond that, you have to investigate the actual physics. In terms of the Higgs mechanism, this requires a basic knowledge of quantum field theory - something you won't find in the public.

He talks of an electron moving around and 'banging into' the Higgs field 'condensate' every 10^-17cm.
That is... problematic.
phinds
#14
Nov26-12, 10:05 AM
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If you think the balloon analogy is a poor analogy, you simply haven't seen a good representation of that analogy. Try this:

http://www.phinds.com/balloonanalogy/


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