Re: Do Neutrinos Have Spin?

Ross A. Finlayson wrote: 
Bjoern Feuerbacher wrote:

Ross A. Finlayson wrote:

Oh, it does say GeV/c^2.  I wonder how I could have misread that.

So, people are positing the graviton to have spin 2. 

Yes. *If* gravitons exist (so far, they are entirely hypothetical),
they *must* have spin 2.



Are quarks indivisible? 

We don't know so far, but so far there is no evidence that they are
divisible.



Why not, if not? 

You could equally well ask: Why, if they are?



Remember, the atom used to be indivisible. 

Used to be *considered* as indivisible.



Are there any metrics of particles that when equipment increases in
precision, grow smaller or larger?  That is, if you were measuring
something about a quark, or other known particle, does the experimental
value or its reciprocal diverge as technology to observe them increases
in precision?


Change, yes, usually (read up on "running coupling constant" and
"running mass"). Diverge, no.



The universe's apparent size appears to be that way over time. 

Huh?


[snip]



In the particleadventure.org chart, it lists spin for fermions as 1/2,
3/2, 5/2, ..., and for bosons as 0, 1, 2, ....  Why is that inductive
sequence ellided?


Because particles with spin higher than 5/2 and 2 exist.



What fantastic particle has spin 99? 

You have to consider that spin is not only a property of *elementary*
particles, but also of *composite* particles. If you combine enough
particles with each other, you can get an almost arbitrarily large spin.



So, things with half-spin, or 1 1/2 or 2 1/2 spin, obey Fermi's rules.
That reminds me of passive electrical components that obey Ohm's and
Kirchoff's laws, I forget.


Huh? Sorry, I fail to see the analogy.



The Fermionic particles, or fermions, they are all hadrons? 

No. Look at the particle chart again. All leptons are fermions. And
leptons aren't hadrons!



So how do I snip a gluon and let it shoot off like a rubber band? 

Not possible. Did you deliberately misunderstand the analogy?


[snip]


Bye,
Bjoern



Hi,

OK, that makes more sense.

I did not deliberately misunderstand, it was more of an ignorant
misunderstanding.

So spin basically is the aspect of the particle that does not
contribute to mass, but may contribute to inertia.


No. Where did you get that from?

"Spin" is a property of a particle which behaves (mathematically and physically) like an intrinsic angular momentum, but which is not (necessarily) associated with an actual rotation of the particle.


Does it contribute
to the inertia of the particle for any non-zero spin?  How much in
terms of mass is this virtual inertia?


I have no clue what you are talking about.


From the first result of "Google" for "running coupling constants",
they have to do with the strong nuclear force, among weak nuclear
force, electroweak, electromagnetic, and gravitic, and vary based upon
the energy where they are measured.

Yes. "running coupling constant" means essentially that the strength of a force depends on the energy at which it is measured.


http://www.clab.edc.uoc.gr/materials/pc/proj/running_alphas.html 

Yes, that describes it rather well.


So basically I'm wondering if the running coupling constant is greater
than one for some energy level or that it goes to zero fo some energy
level, besides arbitrarily increasing the energy level.

AFAIK, neither does happen. Look at the diagram on the page you mentioned above. None of the three lines ever goes to infinity or to 1
(note that 1 over the strength is plotted there!)


I'm not
looking for how these things change from the Big Bang through its
initial development and now as much as an effect where as measurement
precision increases the value diverges,

But an increased precision of measurement in particle physics usually means that one measures at an higher energy.


an observational effect, like
finding a ladder at an apple tree and on every rung the apple tree
grows faster than you can climb, so the fruit on the branch's distance
appears to increase as you approach it.


I never heard of such an effect.


About the universe's size, that's more a question of its predicted
value.  Over time, as various predictions or extrapolations of its size
have been determined, I've never heard of it being determined smaller,
rather than larger, in general terms.  As we learn more about it, it
gets bigger.

Do you know the difference between the *observable* and the *whole* universe? The latter may well be infinitely large.


I've heard that in physics that there are some things in the universe
that mathematically represent singularities or infinities,


Black holes.


besides
their reciprocals I'm looking for things that represent infinitesimals.

What's the difference between a hadron and a non-hadron?

http://en.wikipedia.org/wiki/Hadron

The very first sentence gives the definition:
"In particle physics, a hadron is a subatomic particle which experiences the strong nuclear force."


http://en.wikipedia.org/wiki/Atom

The hadron is a subatomic particle composed of quarks, antiquarks, and
gluons bound by the strong nuclear force. "The gluons mediate the
color force that binds the quarks together." Oh, so that says the
color force, of something called "quantum chromodynamics", binds the
quarks together with some gluon(s) to form fermionic (odd multiple of
half spin) baryons, such as the proton and neutron.

Note that baryons always are fermions, so saying "fermionic baryons" is a bit redundant.


If the electron is a lepton, # 

It is, by definition.


and the neutron is a proton and electron bound or unified in
some way

Huh? It isn't. As you just said yourself above, the neutron consists of quarks.


, .... Quantum chromodynamics is the study of the "SU(3)
Yang-Mills theory" of quarks.


Yes.


I wonder if the quarks are divisible, and if there is some pattern of
divisibility that the resultant forces and particle organizations would
repeat.

You are not the only one to wonder that. People have tried to find experimental evidence for a substructure of quarks for several decades now, and several theoretical models were proposed already. But so far, no results.


Bye,
Bjoern
.

Relevant Pages

  • Re: Book on Pre-MATH for cryptography and cryptanalysis.
    ... She should persuade significant searchs beneath the grumpy insufficient ... Just implementing worth a landowner in search of the journey is too ... laughs the extended bargain very barely? ... Nobody furthermore squeeze plus Abdullah when the marginal suspicions ...
    (sci.crypt)
  • Re: Speed limit at C a misconception?
    ... >combined angular momentum is zero, but each one has a spin of its own ... >of measuring if they have spin up or down would then have led to odds of ... >the sine of 37 degrees squared for each particle *individually*. ...
    (sci.optics)
  • Re: Do Neutrinos Have Spin?
    ... people are positing the graviton to have spin 2. ... >> Are quarks indivisible? ... >> something about a quark, or other known particle, does the experimental ... force, electroweak, electromagnetic, and gravitic, and vary based upon ...
    (sci.physics)
  • Re: A New Foundation for Physics
    ... |> Now tell us why a neutron can be a spin 1 particle if it is a bound ... I wasn't aware that a neutron could be a spin 1 ... experimental evidence that a neutron is mainly three quarks (plus gluons ...
    (sci.physics)
  • Re: QM/EPR/relativity
    ... spin up for certain. ... Then measure the spin of particle 2 along the x-axis. ... both cases measuring the first particle again gives up. ... You might think that the loss of entanglement itself could be used to ...
    (sci.physics.research)