Particle Physics

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Particle Physics

I have been struggling to figure out what, exactly, the relationship between energy and matter is.  What I struggle to understand is the connection at the subatomic level.  I am not well-versed in quantum mechanics, so when I try to read up on it I get lost in jargon and concepts.  Any chance any of you could explain it? 

 

My current understanding would be that the particles that make up electrons, neutrons, and protons, are composed of 'point' particles whose resulting compositions are governed by the  interactions of the 4 fundamental forces.  I fail to see, however, how exactly something has mass at a macro level, but none at a particle level.  ( if that isn't a fallacious statement)

 

Also, in string theory, is it posited that a certain vibration would lend credence to mass?


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v4ultingbassist wrote:I have

v4ultingbassist wrote:

I have been struggling to figure out what, exactly, the relationship between energy and matter is.  What I struggle to understand is the connection at the subatomic level.  I am not well-versed in quantum mechanics, so when I try to read up on it I get lost in jargon and concepts.  Any chance any of you could explain it? 

 

My current understanding would be that the particles that make up electrons, neutrons, and protons, are composed of 'point' particles whose resulting compositions are governed by the  interactions of the 4 fundamental forces.  I fail to see, however, how exactly something has mass at a macro level, but none at a particle level.  ( if that isn't a fallacious statement)

 

Also, in string theory, is it posited that a certain vibration would lend credence to mass?

Couple of quick points:

Electrons may be 'fundamental. but protons are composed of three quarks, and a neutron is equivalent to a proton plus an electron.

Current theory envisages force being conveyed, somehow, by other particles moving between the particles that 'feel' the force.

Photons convey electromagnetic forces, and the hypothetical 'graviton' carries gravity.

Along similar lines, 'mass' is somehow due to the way basic particles interact with something called the Higgs Boson, the most important target of the LHC experiments.

I don't quite follow how these particle interaction lead to field forces and mass, but it seems to work for physicists.

As to matter and energy, I will need more time to sort out my own thoughts...

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OK, I just wanted to make

OK, I just wanted to make sure this connection wasn't clear-cut, or I would've felt like an ignoramus.  I know that protons and neutrons are not considered fundamental.  I also figured the Higgs-boson was an important part of what I don't understand.  


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As a partial response (it's

As a partial response (it's almost dinner time) to your question as to string theory's conception of mass, a string vibrates at a particular resonant energy through an extra-dimensional geometry that confines its vibration such that "physical properties" like mass may be defined. While the extra dimensions are obviously outside the realm of the physically observable, their effect on vibrational patterns nonetheless dictates the properties of the open or closed loop's perception as a fundamental particle.


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v4ultingbassist wrote:OK, I

v4ultingbassist wrote:

OK, I just wanted to make sure this connection wasn't clear-cut, or I would've felt like an ignoramus.  I know that protons and neutrons are not considered fundamental.  I also figured the Higgs-boson was an important part of what I don't understand.  

An apology, I misread your post - I see you already understood that protons and neutrons are composite. I think I jumped ahead to the 'point' particle bit.

Need more sleep....

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Unrepentant_Elitist wrote:As

Unrepentant_Elitist wrote:

As a partial response (it's almost dinner time) to your question as to string theory's conception of mass, a string vibrates at a particular resonant energy through an extra-dimensional geometry that confines its vibration such that "physical properties" like mass may be defined. While the extra dimensions are obviously outside the realm of the physically observable, their effect on vibrational patterns nonetheless dictates the properties of the open or closed loop's perception as a fundamental particle.

 

OK, thanks, that was pretty much how I interpreted it.

 

And Bob, just think about how much sleep you could get if you didn't hang around this forum... I haven't been around long but I've already spent a few nights up later than I should have  


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OK I recommend that you take

OK I recommend that you take two steps back on this one.

 

How are you getting that particles don't have mass?

 

Seriously, there is one class of particles (gauge bosons) that do have a zero rest mass but those are the ones that are associated with forces. The particles that are associated with “stuff” (mainly protons, neutrons and electrons) do have mass. In that particles of stuff have mass, it follows that stuff has mass. There are also a whole host of other particles that have mass as well but for ordinary purposes, we can leave them out for the moment at least.

 

So to get back to your first question, what is the relationship of mass and energy?

 

Well, through the equation E=mc^2, we see that energy and mass are really the same thing. Sort of anyway, by not dropping the math on you, I am missing out on some of the main points to that concept. However, for now, I will treat them as two sides of a coin.

 

Actually, we see this effect in binary star systems. Remember that a body in uniform motion will tent to stay in uniform motion unless it is subject to some energy source that will change the motion. So when two stars are orbiting each other, in that they are bound together, they are undergoing a constant acceleration.

 

Now the energy of the gravitational field is equivalent to some amount of mass and mass has gravitation. Hence, we can see that the orbits are affected by the “extra gravitation” which arises from the extra mass that we should be accounting for in order for the math to work out. If we just go with what “ought to be” the masses of the respective stars, then we will not be able to account for the observations which we make.

 

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v4ultingbassist wrote:I have

v4ultingbassist wrote:

I have been struggling to figure out what, exactly, the relationship between energy and matter is.  What I struggle to understand is the connection at the subatomic level.  I am not well-versed in quantum mechanics, so when I try to read up on it I get lost in jargon and concepts.  Any chance any of you could explain it?

My current understanding would be that the particles that make up electrons, neutrons, and protons, are composed of 'point' particles whose resulting compositions are governed by the  interactions of the 4 fundamental forces.

This is not 100% physics-perfect, but it's a pretty good intuitive explanation. It's how I generally think of particle physics, based on an advanced undergrad course plus keeping up with the science mags like Scientific American etc.

Energy is primary. That's what the universe began with. That's what all the conservation laws work with.

Energy comes in particle/waves. If you think of them as particles, you'll screw up. If you think of them as waves, you'll screw up. When I visualize them, I imagine a kind of standing wave, which can translate through space while maintaining itself in a sort of stable standing wave formation. The standing wave moves around in a particle-like fashion, but it's always a wave regardless. The standing wave is measuring probabilities, so the higher the wave, the greater the probability you'll 'find' the particle/wave at that location. There is no fixed limit to these particle/waves. This means that they pretty much stretch on forever, it's just that the probability for most waves gets really low beyond a certain distance from the centre that it's basically zero, but still not exactly zero. This is why these particle/waves appear to be 'point' particles, but they are really not point particles, they always have some extension in space. There are no true point particles in modern physics, although you might hear people talking that way as a kind of short-hand to avoid dealing with the quantum/wave nature of things.

As for mass, the way I think of it is like this: Primary energy always moves at the speed of light (which is really the 'speed of information' or the 'speed of interaction', since it limits more than just light). Thus, energy particles by default move at the speed of light. It's only when they take on mass that they 'slow' down to sub-light speeds. So, you can think of mass as a kind of state switch: If mass is off, speed is c; if mass is on, speed is sub-c. The connection between mass and velocity is not something they teach you in highschool, but if you ponder for a second you'll see that it's plainly written in E = mc^2.

Another interesting thing about mass is its connection to time, and this is another interesting twist. Massless energy, traveling at speed c, does not experience time. It is 'frozen' in its state until it interacts with another particle, at which time it might change state. But massive particles (matter) experiences time according to relativity in proportion to how 'slow' it is going compared to c (the proportion is not simple, but calculated according to the Lorenz transformations). The faster the particle moves, the less time it experiences. The interesting twist is that if you calculate the combined 'speed' at which the particle is traveling through space and through time, as if time were a forth dimension of space, then you'll find that the combined speed is always c^2 (or c if you take a final square root). So, when a particle is not moving (in its inertial reference frame) it is 'moving through time' at speed c, and when a particle is moving through space at speed c, it is not moving through time at all. So, this interesting twist is that all particles move through *spacetime* at a 'speed' of c, if you consider c to be a spacetime velocity and not just a space velocity.

So mass has this interesting connection to velocity and time. It's a special case of primal energy where the 'velocity' shifts into the time dimension, slowing the particle from its default spatial velocity of c. When this shift happens, mass is required to become non-zero in order to balance everything out.

In regards to forces/interactions: Different particle/waves (both energy and mass) have different physical properties, and so some are able to interact with some physical forces, and others are able to interact with other physical forces. For example, neutrinos tend not to interact with the electromagnetic force, which is why they pass right through most matter so easily. Light, on the other hand, is pretty much defined as a carrier and interactor of electromagnetic force, and so will interact with normal matter, depending on the wavelength of light and the energy states of the electrons in its path.

All matter/energy interacts with gravity, as far as we know. Dark matter is interesting because it's matter (sub-c energy) but it doesn't interact with the electromagnetic force (or any other force, I think, except gravity), which all of our 'everyday' matter does. We humans are fundamentally electromagnetic phenomena. DNA, proteins, water, cells, neurons, brains, consciousness are all governed by electromagnetic interactions. We live in the electromagnetic portion of the universe. Of course, below the level of molecules, we are also nuclear phenomena, interacting with the strong and weak nuclear forces. But dark matter only interacts with gravity. There could be dark matter flying through you right now, and you'd never know because it would only interact with you gravitationally, and I guess it's not as dense as something like the Earth, so the interaction is too weak to feel at this small scale.

Quote:
  I fail to see, however, how exactly something has mass at a macro level, but none at a particle level.  ( if that isn't a fallacious statement)

I'm pretty sure that's fallacious. If the particle is moving as sub-c, it has mass (as far as I know, there may be some esoteric exceptions to this rule). Quarks, for instance, have mass.

Quote:
Also, in string theory, is it posited that a certain vibration would lend credence to mass?

I'm not as strong on string theory, I only read enough to get the gist of it. I'm pretty sure that string vibration is somewhat analogous to the 'standing wave' idea I was describing earlier. The vibration probably confers the physical properties of the particle.

But I sense a confusion in your question which I'm more confident to answer: Mass is not a property that is continuous from X down to zero. It's more like a switch, as I tried to explain earlier. You either have mass or you don't. Similarly, you're either moving at c or you're not. A particle is either a massless particle, and it moves at c, or it has mass and does not move at c (again, there may be esoteric exceptions, but for a simple intuitive idea, this will serve you well).

So, a continuous change to string vibration won't slowly turn on mass, it would have to be a fundamental change in the string, from one kind of 'standing wave' to a different kind. This is how mass particle/waves can transform into energy particle/waves, again, according to E = mc^2. Usually you don't get full conversion from mass to energy. I think most, if not all, transformations are from one mass particle/wave to another mass particle/wave plus some energy, or one m p/w to two m p/ws plus some energy, or what have you. What I gather is happening here is that one string with a particular 'standing wave' pattern snips off another smaller string with a different pattern. But I think the mass/velocity relationship is the most important thing to remember when thinking about this. Either the new string is massless and moves at c, or has mass and moves at sub-c.

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Bob Spence wrote:Current

Bob Spence wrote:

 

Current theory envisages force being conveyed, somehow, by other particles moving between the particles that 'feel' the force.

Photons convey electromagnetic forces, and the hypothetical 'graviton' carries gravity.

Along similar lines, 'mass' is somehow due to the way basic particles interact with something called the Higgs Boson, the most important target of the LHC experiments.

If I may add some pedantry here, Bob, the photon and the "graviton" are also bosons which are particles with integer spin (the spin number is relevant to the statistics that characterise the particle), like the Higgs Boson. And thus the Higgs Boson is a hypothetical force carrier and mediator, rather than what the particles interact with which is the Higgs Field (analogous to an electromagnetic field).

 

In any case, vaultingbassist, as AIG said, most fundamental particles are not massless. Could you clarify your question?

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I hope I'm not the only

 

natural wrote:

Energy comes in particle/waves. If you think of them as particles, you'll screw up. If you think of them as waves, you'll screw up. When I visualize them, I imagine a kind of standing wave, which can translate through space while maintaining itself in a sort of stable standing wave formation. The standing wave moves around in a particle-like fashion, but it's always a wave regardless. The standing wave is measuring probabilities, so the higher the wave, the greater the probability you'll 'find' the particle/wave at that location. There is no fixed limit to these particle/waves. This means that they pretty much stretch on forever, it's just that the probability for most waves gets really low beyond a certain distance from the centre that it's basically zero, but still not exactly zero. This is why these particle/waves appear to be 'point' particles, but they are really not point particles, they always have some extension in space. There are no true point particles in modern physics, although you might hear people talking that way as a kind of short-hand to avoid dealing with the quantum/wave nature of things.

 

person on the thread whose brain exploded at the end of this paragraph.

 

 

 

 

 

 

 

 

 

 

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Atheistextremist

Atheistextremist wrote:

 

natural wrote:

Energy comes in particle/waves. If you think of them as particles, you'll screw up. If you think of them as waves, you'll screw up. When I visualize them, I imagine a kind of standing wave, which can translate through space while maintaining itself in a sort of stable standing wave formation. The standing wave moves around in a particle-like fashion, but it's always a wave regardless. The standing wave is measuring probabilities, so the higher the wave, the greater the probability you'll 'find' the particle/wave at that location. There is no fixed limit to these particle/waves. This means that they pretty much stretch on forever, it's just that the probability for most waves gets really low beyond a certain distance from the centre that it's basically zero, but still not exactly zero. This is why these particle/waves appear to be 'point' particles, but they are really not point particles, they always have some extension in space. There are no true point particles in modern physics, although you might hear people talking that way as a kind of short-hand to avoid dealing with the quantum/wave nature of things.

 

person on the thread whose brain exploded at the end of this paragraph.

 

 

I've read it a few times myself

 

But I think this addresses my question best.  Eloise, I was basically asking how energy becomes matter.  Because matter can be converted to energy (again annihilation is an example of this), it is my understanding that EVERYTHING is some form of energy.  I'm just trying to understand how energy can become matter.  If the above quote works, I think I understand now. 

 

AIG, I added the fallacious statement bit because it didn't make sense to me, but that's how I've seen it written, and misinterpreted that as being the case.  Also, feel free to drop math on me.  I am not adverse to calculus, and am usually interested in how it works.

 

Natural, could you expand on your thoughts?  You say that "when they take on mass that they 'slow' down to sub-light speeds." At this point is some of the energy 'slowing down' and thus forming the physical property of mass?  Or am I misinterpreting your explanation? You talked of mass 'turning on and off' by necessity, is this process understood?

 

 

And thanks for the responses, definitely helpful.

 

EDIT:  I am also treating matter and mass as synonymous in this discussion, just in case this is causing any confusion.  I am mainly concerned with understanding the transition between energy and 'substance.'  AKA energy becoming substance.


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v4ultingbassist

v4ultingbassist wrote:
natural wrote:

Energy comes in particle/waves. If you think of them as particles, you'll screw up. If you think of them as waves, you'll screw up. When I visualize them, I imagine a kind of standing wave, which can translate through space while maintaining itself in a sort of stable standing wave formation. The standing wave moves around in a particle-like fashion, but it's always a wave regardless. The standing wave is measuring probabilities, so the higher the wave, the greater the probability you'll 'find' the particle/wave at that location. There is no fixed limit to these particle/waves. This means that they pretty much stretch on forever, it's just that the probability for most waves gets really low beyond a certain distance from the centre that it's basically zero, but still not exactly zero. This is why these particle/waves appear to be 'point' particles, but they are really not point particles, they always have some extension in space. There are no true point particles in modern physics, although you might hear people talking that way as a kind of short-hand to avoid dealing with the quantum/wave nature of things.

I've read it a few times myself

Check out these videos for how you might visualize standing waves:

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

http://www.youtube.com/watch?v=tI6S5CS-6JI

http://www.youtube.com/watch?v=t0FsSYLH_SY

Now imagine these standing waves have no limit but just diminish in amplitude really quickly from the centre so that they seem mostly like a 'point' in space. But it's not really a point, because the wave itself takes up space. Something like this:

----------------~~mWm~~--------------------

At a small scale, it's clearly a wave, but at a bigger scale it appears to be a 'point' particle. Here's a wave/particle in motion in 1D:

t1: ---~~mWm~~---------------------------------

t2: ------------------~~mWm~~------------------

t3: ---------------------------------~~mWm~~---

Extend this metaphor into three dimensions, and you have a wave/particle.

Quote:
Natural, could you expand on your thoughts?  You say that "when they take on mass that they 'slow' down to sub-light speeds." At this point is some of the energy 'slowing down' and thus forming the physical property of mass?  Or am I misinterpreting your explanation? You talked of mass 'turning on and off' by necessity, is this process understood?

I used 'slow' with quotes to indicate it's a loose metaphor. You have to think in terms of interactions to understand physics. Two things with particular states interact and out come two different things with different states. The energy doesn't literally slow, what happens is that an interaction occurs such that one of the resulting things coming out of the interaction is energy with a particular state wherein that energy has two measurable properties: Non-zero mass, and sub-c speed. These properties are linked, as I described earlier, meaning if you have one, you have the other, which is what I meant by it being like a 'switch'.

Below the level of interaction, no, it is not understood. That's why they are called fundamental forces. Actually, they are really called fundamental interactions, which is why I said you have to think in terms of interactions.

Sometimes, due to quantum nature, an 'interaction' can occur without an obvious outside 'cause'. These can be called quantum fluctuations. A particle/wave can suddenly decompose into some other particle/wave(s). This is related to what I said earlier about the 'standing waves' being measures of probability. There is a fundamental limit to predictability of interactions. They are statistical and probabilistic at the quantum level. If you think about particle/waves as standing probability waves, it helps visualization.

So, I don't know the exact process by which the initial energy of the universe became partially matter, but the explanation will be in terms of fundamental interactions at a probabilistic quantum level. Some energy 'interacted' with itself splitting into gazillions of particle/waves, and some of those interacted in such a way as to take on the linked properties of non-zero mass and sub-c speed. That's essentially how energy gave rise to matter. The more complex details I leave to the experts. I'm satisfied with my intuitive understanding, and if I need to look up the facts, I'll be able to understand them.

Quote:
EDIT:  I am also treating matter and mass as synonymous in this discussion, just in case this is causing any confusion.  I am mainly concerned with understanding the transition between energy and 'substance.'  AKA energy becoming substance.

Matter is energy which has mass at a sub-c velocity. Mass is the property associated with gravity. It is relativistic, being based on a 'rest mass' which is measured as if the object were not moving (inertial reference frame). Thus while light and other energy is massless while moving at c, it still has a 'rest mass' equal to its energy divided by c^2 which is how Einstein predicted that it would bend in the presence of a strong gravitational field. So, no, mass and matter not synonymous.

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natural wrote:Quote:EDIT: 

natural wrote:

Quote:
EDIT:  I am also treating matter and mass as synonymous in this discussion, just in case this is causing any confusion.  I am mainly concerned with understanding the transition between energy and 'substance.'  AKA energy becoming substance.

Matter is energy which has mass at a sub-c velocity. Mass is the property associated with gravity. It is relativistic, being based on a 'rest mass' which is measured as if the object were not moving (inertial reference frame). Thus while light and other energy is massless while moving at c, it still has a 'rest mass' equal to its energy divided by c^2 which is how Einstein predicted that it would bend in the presence of a strong gravitational field. So, no, mass and matter not synonymous.

 

I just meant that I may have said 'mass' when referring to matter, in regards to my attempt to say 'energy with mass at sub-c.'  I know they are not synonymous.

 

Thanks for the explanation.  It certainly makes more sense now than it did before.


 


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I have read all the posts on

I have read all the posts on this thread, and my eyes are now crossed with x's  over both.

But, I've given this ALOT of thought over the past 15 years or so. And, feel free to laugh if you want, but

here is my take on it.

 

I tried to imagine the 'singularity' that is claimed by many experts which was the precursor of the big bang(rapid expanse) from which all matter came into existence. It was difficult for me until I realized that since matter and energy are interchangable via E=mc^2  , a limitless amount of energy can exist in a zero volume amount of space. as without mass no space is needed, energy doesn't occupy space, mass does. Without mass that interacts, no motion occurs, without motion, no time is needed as time is a measure of the motion of mass. This making any sense to anyone?

 

I think that all mass that we can perceive and all that we can't could easily have been an unbelievably large amount of energy that was at an unbelievably huge temperature occupying no space and without time until it 'condensed' and dropped to a temperature that allowed matter to form rapidly at first and slowing exponentially over time.

I also think that is why time dilation exists for objects in motion and accerleration. We know time dilation exists, but I can't find a single reason as to what the actual cause is.

Stay with me here,  If an object travels from point A to point B, it experiences less time than if it had remaind stationary. Suppose the object undergoes much the same effect that an electron does when raised to a higher energy level. From one quantum state to the next higher quantum state without ever being between those states.

Suppose the traveling object experiences a matter to energy to matter..etc  existence during the acceleration(energy input) and doesn't experience 'time' while it is in an energy state. That would explain the time loss of the object in question.

 

Any thoughts?  Anyone?

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Well WV, you are all over

Well WV, you are all over the place on this one. The first thing that I would suggest is that you don't worry too much about singularities. All of physics breaks down when you get close to one. Well, actually physics itself obviously can't just fall apart but everything that we have managed to make sense of in other areas pretty much doesn't work in any way that we can make sense of.

 

As far as E=mc^2 goes, that tells us that energy and mass are really the same thing. So if you have some quantity of energy, that energy will have an associated gravitational field. I mentioned the matter briefly with binary stars, mainly because that is a fairly obvious place where there is lots of energy but any amount of energy will have gravitation.

 

As far as time dilation goes, that does not need a cause or at least not any greater cause than the relative motion of two bodies. Allow me to explain:

 

Say for example that you and your brother are in two star ships which are parked right beside each other. Further, say that you each have a clock that is connected to a radio so that you can each listen to the other one's clock ticking. Since you are parked next to each other, both of you hear the other one's clock tick once per second.

 

Now, if the two of you head away from each other at half the speed of light (important note: This is the relative velocity between the two of you), then you are going to hear something different. Each time your clock ticks, it has farther to travel before your brother can hear the radio signal. The same holds true for you hearing your brother's clock.

 

Provided that the relative velocity remains constant, what each of you will notice is that the time between the ticks is just a bit slower than once per second. Because the distance between the two of you is increasing at a steady rate (in this case half a light second per second), the rate at which you hear the ticks is slower by the amount required by the uniform relative motion.

 

A related phenomenon is the Lorentz Fitzgerald contraction. The easiest way to visualize this would be if you were in a train heading down the tracks at half the speed of light (yes that is odd but run with it for now). Say that the telegraph poles are uniformly spaced along the tracks.

 

Because you are heading toward the poles at a very large velocity, you have to wait less time for the light from each pole to reach you in the engineer's cabin (than would someone in a similar but stationary train). So you will measure the poles as being closer together than the guy in the stationary train will.

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