Is the Proton's Half Life Really 10 to the Power of 32 Years?

[garytse86]

you can say that a proton is not stable chemically, that's why you get h30+ ions, the proton is not going to sit in solution doing nothing

 

[chroot]

gary:

Compounds of hydrogen have nothing to do with the stability of the proton itself.

- Warren

 

[Mr. Robin Parsons]

But I would be curious to know if, in separating protons from their respective electrons, by ionizational energies, (then a magnet to evacuate the protons), if placed back into an ionizing chamber, then turning the ionizing energy off, will the electrons that were once there, re-appear, from the energy that the ionization process imparted?

 

[chroot]

If you separate electrons from protons, you have a box of electrons and a box of protons. You can't destroy electrons, nor can you create them.

- Warren

 

[garytse86]

yes but in an acid, you don't get H+ ions but H30+ ions instead

 

[Terry Giblin]

Where did all the electrons disappear too?

If you separate electrons from protons, you have a box of electrons and a box of protons. You can't destroy electrons, nor can you create them.

- Warren

Warren,

Assuming you now have a box of electrons, and the walls of the box, act as a square-square potential well - quantum barrier which we can control, to release only one single electron at a 'time'.

Now we build two concentric circular walls around the box, the inner wall has two slits in it and the outter wall is painted white.

How did the electrons tunnel throught the wall?

Where do all the electrons disappear too?

Where did all the photons appear from and how?

I can only see a intereference wave pattern, but no electrons?

"You can't destroy electrons" - or matter or energy only change its form.

Regards

Terry Giblin

 

[ahrkron]

yes but in an acid, you don't get H+ ions but H30+ ions instead

How is that relevant?

In a chemical reaction, by definition the number of protons do not change. Actually, even the number of protons in each nucleus is not altered.

 

[garytse86]

How is that relevant?

In a chemical reaction, by definition the number of protons do not change. Actually, even the number of protons in each nucleus is not altered.

yes but the proton is not chemically stable otherwise it would not form an ion with H2O.

 

[chroot]

We're not talking about "chemical stability," gary, for the last time.

- Warren

 

[chroot]

I have split off MRP's discussion of whether or not chemistry includes nuclear effects to the Theory Development subforum.

- Warren

 

[IooqXpooI]

Isn't a proton just a combination of quarks?

It is stable, yet turns into a Neutron by means of Weak Force quickly...(in the atom)

 

[Nereid]

Isn't a proton just a combination of quarks?

Yes.

It is stable, yet turns into a Neutron by means of Weak Force quickly...(in the atom)

I think you mean 'in a nucleus', and only in certain cases, e.g. where it can capture an orbital electron, and where the resulting nucleus has lower energy than the starting one, ...

 

[Mr. Robin Parsons]

And in radio-active decay, it reverts back to a proton, from a neutron by decay emitance of either, an electron, or a positron. (and a neutrino too, I suspect, I recall)

 

[chroot]

Beta decay:

n \rightarrow p + e^- + \overline{\nu}_e

- Warren

 

[Haelfix]

Note the inverse process is not a 'decay', its a reaction... One with very small cross section too I might add.

So the point stands, the proton has nothing to decay into... In nuclear and particle physics, any situation like that is defined to be 'stable'. Note this is not the same meaning as a chemist would use, where typically you aren't dealing with extreme vacuums.

You have to go beyond the SDM* to find a mechanism for its decay. (*aside from one technicality which has vanishingly small contribution)

 

[Antonio Lao]

What I don't understand is why the sum of the mass of the quarks composing the proton is larger than the mass of the proton.

Experimentally it can be said that the formation of proton liberates mass in term of energy because it takes about the same energy to form the jets which have proven the existence of quarks. But individual quark cannot be isolated. How much more energy does it takes to isolate the quark?

 

[Mr. Robin Parsons]

Have protons been created experimentally? or are you simply referring to the math's prediction(s)?

 

[Antonio Lao]

Experimental verification of quarks by the formation of jets proving the compositeness of nucleons and mesons of all hadrons.

 

[chroot]

What I don't understand is why the sum of the mass of the quarks composing the proton is larger than the mass of the proton.

You have it backward. The proton has more mass than the sum of its constituent quarks, because the binding energy between them counts as additional mass via E=mc².

How much more energy does it takes to isolate the quark?

You can't isolate quarks, because the energy required to pull two apart is more than the energy required to create two more. In other words, you can pull a pair apart to a point and then *pop* you'll wind up with two pairs.

- Warren

 

[Mr. Robin Parsons]

Uhmmm, this was the question I had asked: "Have protons been created experimentally?" Lord knows what question you answered...

 

[Antonio Lao]

The natural decay of the "free" neutron does produce a proton as shown by trivial experiments requiring a lot less energy than all other modern accelerators.

 

[chroot]

I'd like to make sure that you understand, Robin, that these protons are not being created out of nothingness; that would violate many conservation rules. Instead, when you smash bits of matter together in particle accelerators, the kinetic energy of the particles can be manifested in the creation of various kinds of particles, some very exotic -- that's the fun part. In no situation does an experiment end up with more mass and energy than it started with, however.

- Warren

 

[Antonio Lao]

Robin Parsons,

As a novice in any experimental process, I know I don't how to create a proton. And I don't recall any experiment done by the experts. But in the early age of the universe, I think, it was naturally done by the first nucleosynthesis?.

 

[ZapperZ]

Just to make sure that there are NO misconceptions about our ability to create protons experimentally, we can do this the quick and dirty way (zap a hydrogen atom with enough energy and voila! We have a proton), or systematically to generate a high "quality", low emittance, high brightness proton beam as done routinely at Fermilab and many other accelerator/collider facilities.

http://www.fnal.gov/pub/inquiring/physics/accelerators/chainaccel.html

Zz.

 

[Antonio Lao]

I am thinking more in the line of creating proton from the component quarks than that of dissociation of hydrogen atoms.

 

[ZapperZ]

I am thinking more in the line of creating proton from the component quarks than that of dissociation of hydrogen atoms.

Yes, I was aware of that. I was merely addressing to the broader issue of "can we create protons experimentally", in case there are peole jumping in in the middle and see a discussion that might give them the impression that we do not know decisively that we have created protons.

As for your line of thinking, either beta decay (change of flavor by quarks) might answer your question, or you will have to wait till we make and verify the first gamma-gamma collider.

Zz.

 

[Antonio Lao]

Sorry for my being narrow and one trackly minded.

 

[taxman]

If the theroies are correct mass and energy are essentially the same thing just in a different form. It is not impossible for a decay of protons. Everything changes so over time it is not unlikely that the energy of the proton would decay into its principle parts. I just don't think that we know or understant all of the parts yet.

 

[chroot]

taxman,

According to the standard model, it is absolutely impossible for protons to decay. The argument "everything changes over time" is not a strong one at all.

- Warren

 

[Nereid]

If the theroies are correct mass and energy are essentially the same thing just in a different form. It is not impossible for a decay of protons. Everything changes so over time it is not unlikely that the energy of the proton would decay into its principle parts. I just don't think that we know or understant all of the parts yet.

Welcome to Physics Forums, taxman!

As chroot said, the proton is a stable particle in the Standard Model, so it will not decay (by itself; there are certainly situations under which it will 'decay' e.g. in certain proton-rich nuclides). Of course, one of the tests of the Standard Model is to look for decays of the proton. AFAIK, several research projects to find proton decays, by a wide variety of channels, have been undertaken. No confirmed proton decays have been observed, so we can conclude that the proton's 'half-life' is at least 10³⁸ years (though it may be somewhat less, in some hypothesised decay modes).

To put this into context, a proton half-life of 10³⁸ years would mean an expectation of just *one* decay in ~12,000 moles of ordinary hydrogen, in a period of time equal to the life of the universe to date!