# How can a free elementary particle really be a particle

• hurk4
In summary, the conversation is discussing the relationship between free elementary particles and the Planck mass. The Planck mass is the smallest mass that can be attributed to a particle and has dimensions that are inversely proportional to its mass. Some believe that this is the fundamental scale of the universe, but others argue that there are other scales and dimensions that influence the strength of gravity. The conversation also touches on the concept of Compton particles and Compton wavelength, which are related to the mass of a particle. However, it is debated whether these particles can still be considered "free" when detected by a detector. The conversation also mentions string theory and bi-scale theories, which propose that the Planck scale is not a fundamental scale and is instead a
hurk4
Free elementary particles are lighter than the Planck mass, how can the exist as particles, or are they just Compton particles having a Comton waveleght?

What is a "Compton particle"?

What is a "Comton waveleght?"

Lots of things are lighter than the Planck mass (which is not all that small at around 10^-8kg). I don't see how a Planck mass has anything to do with particles being particles.

jtbell said:
What is a "Compton particle"?

Dear jtbell,

Here I give you the background i used to pose my question.

The Planck length is the smallest length one can physically attribute to a particle it corresponds to the smallest Schwarzschild black hole which is physically possible.
Blackholes have dimensions inverse proportional to their mass.
To "particles" lighter than the Planck mass one can attribute a Compton wavelenght which is inverse proportional to their mass.
In my question i gave them the name "Compton particle" because I have no better indication.
Below I give you a description of the Compton wavelenght as you can find in Wikipedia

The Compton wavelength is a quantum mechanical property of a particle. It was introduced by Arthur Compton in his explanation of the scattering of photons by electrons (a process known as Compton scattering). The Compton wavelength of a particle is equivalent to the wavelength of a photon whose energy is the same as the rest-mass energy of the particle.

hurk4 said:
Dear jtbell,

it corresponds to the smallest Schwarzschild black hole which is physically possible.

Correction: Of course it is proportional to its black hole mass

regards
hurk4

hurk4 said:
Free elementary particles are lighter than the Planck mass, how can the exist as particles, or are they just Compton particles having a Comton waveleght?
You misunderstood something. The mass of the elementary particle has nothing to do with its wavelength.

Matterwave said:
Lots of things are lighter than the Planck mass (which is not all that small at around 10^-8kg). I don't see how a Planck mass has anything to do with particles being particles.

Dear Matterwave

At the Planck mass Compton wavelenght and Schwarzschild radius are about equal. So I suppose at lower mass free particles are compton waves.
kind regards
hurk 4

Demystifier said:
You misunderstood something. The mass of the elementary particle has nothing to do with its wavelength.

Yes, it does. They are deeply related. Compton wavelength in Planck units of length, and Compton frequency in Planck units of time, are equal to the inverse of particle's mass in units of Planck mass. Compton frequency is the native frequency of the particle, it is the frequency with which rest solutions of Dirac and Klein-Gordon oscillate.

This is all well and good, but I still don't understand what it has to do with anything.

The "smallest wavelength", "highest point-like energy", etc all correspond to the Planck length/time/mass in various units.

But this has nothing to do with the definition of the word "particle" - that comes from a detector: for example, when we shine a VERY low-intensity light at a florescent screen, we find that we see little "blips" that are isolated from each other. We interpret these as "particles" of light. The same experiment exists for electrons, neutrons, etc, suitably generalized.

None of that has anything to do with Planck-anything!

blechman said:
This is all well and good, but I still don't understand what it has to do with anything.

The "smallest wavelength", "highest point-like energy", etc all correspond to the Planck length/time/mass in various units.

But this has nothing to do with the definition of the word "particle" - that comes from a detector: for example, when we shine a VERY low-intensity light at a florescent screen, we find that we see little "blips" that are isolated from each other. We interpret these as "particles" of light. The same experiment exists for electrons, neutrons, etc, suitably generalized.

None of that has anything to do with Planck-anything!

I said "free particle"
Once it is located in your detector it is not free anymore and the compton wavelengh has gone. And in that situation I would not give it such a name like Compton particle.
Maybe you can explain me what is wrong with this questioning?

kind regards hurk4

hurk4 said:
The Planck length is the smallest length one can physically attribute to a particle it corresponds to the smallest Schwarzschild black hole which is physically possible.
Blackholes have dimensions inverse proportional to their mass.
[/B]

The source you are using is an interpretation based a belief that Plank's level is fundamental. This is the level usually associated with string theory.

This is
1) not a fact but a belief [not a well substantiated, but a problematic belief, see 2), 3) 4) ]

2) the basis for this belief is not actually a requirement of string theory but certain versions of string theory. These versions of string theory all fail to produce the magnitude of gravity.

3) is "disproved" by the versions of string theory that can produce the magnitude of gravity, which propose that space-time is bi-scalar [a solution to (conversely as implied by) the Hierarchy Problem].

4) Planks scale theories produce a cosmological constant that is 10^128 times too large, bi.e 10^128 WRONG! Not exactly an indorsement! (I may be off by a couple of powers of 10 but after 20 or 30 powers of 10 who cares).

As indicated by the authors N. Arkani-Hamed, S. Dimpopoulus, and G. Dvali, [The hierarchy problem and new dimensions at a millimeter'', Phys. Lett. B429 263-272 (1998)] the implication of a bi-scale string theory is that Planck scale is not a fundamental scale; its enormity is simply a consequence of the large size of the new dimensions.".

It is the inter-scale interaction between the regular strings and
the large strings that results in producing the weakness of
gravity. Ignoring the bi-scale source of this weakness results in
the false view that Plank's scale is fundamental.

Also see, I. Antoniadis, N. Arkani-Hamed, S. Dimpopoulus, and G. Dvali, New dimensions at a millimeter to a fermi and superstrings at a TeV'', {\it Phys. Lett.} {\bf B}, {\bf 436} 257-263 (1998)

Last edited:
enotstrebor said:
The source you are using is an interpretation based a belief that Plank's level is fundamental. This is the level usually associated with string theory.

Dear enotstrebor,
It is not just in some of the string theories but it is also in other new theories like Loop Quantum Gravity that Planck units are used.
In physics forums there are several extended threads discussing Planck units such as "Is the Plancklenght a commonly accepted theory or is it controversial anyway"? A nice answer I like is that of Marcus in his post nr.2.
Or "How can the Planck length be claimed to be the smallest lenght"? etc. etc.

Any way I must agree that Planck units are not experimentally verified but I would say that my convinction that they exist is more than just a belief. The Planck era IMO is a way to save physics from an unphysical singularity (even non realistic) and new theories like LQG are giving me hope that finaly we can really go beyond a big bang started from an infinite small point at time zero.

Regards
Hurk4

## 1. How can a free elementary particle really be a particle?

The concept of a free elementary particle refers to a particle that exists independently and is not bound to any other particles. These particles are considered to be fundamental building blocks of matter and cannot be broken down into smaller components. They have properties such as mass, charge, and spin, which make them behave like particles. Therefore, they are classified as particles despite their tiny size.

## 2. What evidence supports the existence of free elementary particles?

There is a vast amount of evidence from experiments and observations that support the existence of free elementary particles. For example, high-energy particle accelerators have allowed scientists to observe the interactions and behaviors of these particles. Additionally, the Standard Model of particle physics, which is a well-tested and accepted theory, includes all known elementary particles and their interactions.

## 3. How do free elementary particles interact with each other?

Free elementary particles interact with each other through fundamental forces such as electromagnetism, weak nuclear force, strong nuclear force, and gravity. These interactions are mediated by particles such as photons, gluons, and W and Z bosons. The type and strength of the interaction depend on the properties of the particles involved.

## 4. Can free elementary particles be created or destroyed?

According to the Law of Conservation of Mass and Energy, matter and energy cannot be created or destroyed. Therefore, free elementary particles cannot be created or destroyed. However, they can be converted into different types of particles through interactions with each other or with high-energy particles.

## 5. How are free elementary particles related to the composition of matter?

Free elementary particles are the building blocks of matter. They combine to form atoms, which then make up all the elements and compounds in the universe. The properties and interactions of these particles determine the properties of the matter they compose. Therefore, understanding free elementary particles is crucial to understanding the composition and behavior of matter.

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