How Does the Higgs Field Affect Particle Mass?

[ChrisVer]

How does having a non-zero vev gives particles mass.

The main thing is to understand that the mass of the fields appear in the Lagrangian density as (field)² terms (field self-interactions). One possible explanation that can help you understand it, is that the fields will have to contain some certain amount of energy just to exist (to have the mass) and that's 1 reason why the quadratic terms of fields are the mass terms (Lagrangian and Hamiltonian are both connected to the energy of your system). Another way is that they will give the correct equations of motion for the fields.

Then you can go to the Lagrangian and see what is happening if you allow for a Higgs field. There is a Yukawa term allowed in your lagrangian which will couple two fermionic fields to a scalar one. Since the Higgs field H is a scalar it's able to be coupled to your fermions F in the form:
\bar{F}HF . If now the Higgs field H has a vev different to zero, then it means that this interaction term will give some energy even if you are looking at the vacuum value. Let's say that this vev is a you will get:
\bar{F}HF=a \bar{F}F
where then you can say that a is the (bare) mass.

The Higgs boson will appear by perturbing around the vacuum, that is doing something like: H(x)= a + h(x) then you will also have a term like: a \bar{F}F+ \bar{F} h(x) F which will correspond to your fermions having a mass a coming only because of the Higgs field's vev, and also interact with the Higgs boson (not so strongly interesting).

 

[ChrisVer]

Can matter made up of composite particles acquire mass when moved through higgs field?

In fact why would someone try to answer this question? if you have composite particles, they must consist of some elementary particles that acquire their masses from the Higgs vev. So it depends on what you are trying to see as an answer (?).

 

[phinds]

Sorry phinds to reply a bit late to this. By chance I happened to read a post regarding this. I was saying "Just as it is hard to push a car to increase (or decrease) its speed because the car has a big mass, the more massive a particle the harder it is to CHANGE its speed."
.

And AGAIN, I have to ask, "change it's speed RELATIVE TO WHAT?". You continue to seem to think that things have a "speed" all by themselves and that just is not true. Everything is at rest relative to itself. I think what you are doing here is using shorthand for "take two particles at rest relative to each other and change their relative speed" or something like that, but the kind of sloppy phasing you have used regarding "speed" either leads to or comes from sloppy thinking, so should be avoided.

Alternatively, perhaps it is that you think there is some absolute "aether" rest frame and you can talk about things moving relative to it, but there is not.

 

[Drakkith]

Let's not be too hard on the OP. We are all aware of how difficult it is to explain advanced physics to people who have little experience in science. The fact that poor analogies, such as the celebrity moving through a crowd, are routinely touted as an example of how something works only makes it more difficult. I for one don't blame the OP for having such difficulty at all.

That being said, Avito, it is important to understand that much of what you've commonly read or heard has been simplified and watered down to the point of being outright wrong in some cases. The only way to make progress is to start by getting a firm grasp of classical mechanics first and then move on to more advanced concepts later.

 

[jtbell]

Inspired from Einstein who presented a paper when he was a clerk in patent office.

Note that he studied physics for many years, was well aware of all the current research back then and was in contact with other physicists.

While he was working in the patent office, Einstein was what we would nowadays call an "ABD" = "All But Dissertation". He had completed his formal studies towards a Ph.D. and needed only to finish his dissertation and submit it, which he did in fact do in 1905, shortly before he published his famous relativity paper.

 

[nikkkom]

http://profmattstrassler.com/articl...s-basics/how-the-higgs-field-works-with-math/

This article explains, *with math*, how exactly Higgs field (a scalar field with nonzero vev) gives mass to excitations (particles) of another field.

The math in this article is greatly simplified, but it is still better than attempts to "explain it in layman's terms" without math.

 

[TumblingDice]

Hello avito009,

I've been following this thread and would like to try to help. Some of what you've written is on the right track, yet it's mixed with misunderstandings. The mentors and members who've stressed that a deeper understanding of prerequisite physics topics is required to fully understand is true. Speaking for myself, perhaps they think of the 'cocktail party' analogy and how misleading it is when they offer this viewpoint.

I'm not an expert and can't explain the Higgs mechanism, but I think I can help to form a good foundation for future questions by offering my layman's explanation to establish some terminology and possibly remove the misconceptions. You've mentioned moving and motion, rest mass, and change in speed.

1) The first terminology I'll mention is an IRF (inertial reference frame). An IRF is a frame of reference that can either be described as "at rest" or "moving with a constant linear velocity". Simply put, it is not being acted upon by any forces that cause it to change direction or speed.

2) Rest mass is a specific term for the mass of an object as observed in its IRF. There are other flavors of 'mass', but they're not relevant to this discussion. In modern physics the term 'mass' is expected to refer to 'rest mass' unless otherwise noted. Mass is sometimes referred to as the resistance to change in motion. Ergo, measuring mass requires acceleration.

3) Acceleration is a change in velocity. As a vector, velocity has a rate (speed) and a direction. Acceleration can be measured when either the speed or direction of an object is changing.

Before proceeding, let's set aside any queries that you received asking about motion "relative to what?" This doesn't matter and might cause confusion.

I was saying "Just as it is hard to push a car to increase (or decrease) its speed because the car has a big mass, the more massive a particle the harder it is to CHANGE its speed."

This is on a good track. Changing speed is acceleration, and that is when mass raises its head.

Very early on I thought you had been looking at the "cocktail party" analogy which, as ChrisVer and mfb pointed out, these are inaccurate explanations.

the molasses analogy is not the description of what the Higgs field does.

I don't like the cocktail party analogy, because it gets the "velocity is not acceleration" part wrong.

"Moving" through the Higgs field is a poor analogy. I hope I'm following @mfb properly when he mentions "velocity is not acceleration". Acceleration is absolute and can always be measured (thanks to the Higgs mechanism).

Not to tangent - but only to explain an aspect of the equivalence of gravity and acceleration. On Earth the terms mass and weight are often used interchangeably. Yet weight is dependent on the strength of the gravitational field that's acting on the mass. We know the acceleration gravity causes here on Earth. The acceleration of an object due to Earth's gravity (at the surface) is 32 feet/sec/sec. Bathroom scales are calibrated to measure weight (mass) based on this value. If you tried weighing yourself in an elevator that was accelerating upward, the scale would measure incorrecty because of the additional acceleration.

I'm going to pause here to give you time to read, and the experts time to correct any mistakes! :)

 

[ChrisVer]

Mass is sometimes referred to as the resistance to change in motion.

That's the definition of inertial mass.

 

[TumblingDice]

That's the definition of inertial mass.

I gotcha' CV. Inertial framing is what I thought would help to establish a basis to build on. Thank you for helping me with the appropriate terminology. Does this mean you were "mostly OK" with the rest of my post? Thanks again!