physics, a true kind of magic

something I can't understand, a proton consists of 2 up quarks, 1 down quark, { up, up, down } , and gluons holding them together, while a neutron consists of 1 up quark, 2 down quarks, {up, down, down } , and gluons. The decay process in simple terms occurs because a down quark changes into an up quark Neutron{ up, down, down } - beta decay -> proton{ up, up, down } and emits an electron and an anti-neutrino. The important thing to note (something I can't understand) is that the electron and anti-neutrino weren't there before. They were created at the time this weak force reaction took place X____________X

so, one of the down quarks in the neutron gets converted into an up quark, an electron and an antineutrino through the mediation of the weak force: that's a kind of magic!

and ... about gluons ... well a proton has a mass of 938,272 MeV, if you sum the mass of three quark particles inside the proton you get 9 MeV, while a neutron has a mass of 939,568 MeV, if you sum the mass of three quark particles inside the neutron you get 12 MeV

proton: { up, up, down } = 9 MeV, { up, up, down } + gluons = 938,272 MeV neutron: { up, down, down } = 12 MeV, { up, down, down } + gluons = 939,568 MeV

that means that gluons convert energy into mass (E=m*C^2 ?!?), W@!!£!T$$!"F$!"£!?!?!?!

also experiments confirm that the neutron is really composed of three quarks, and it is a an intuitive mistake to imagine that if a particle X decays to YZ, then X is the "same thing" as YZ. One may say that it has the same conserved charges, but conserved charges don't fully define the identity of an object, therefore a neutron [u]is not[/u] a proton and an electron lumped together, things are more complex, the electron and anti-electron-neutrino appear when one of the down quarks decays into an up quark { up, (down), down } -> { up, (up), down }, and a W-boson, and the W-boson then decays into an electron and an anti-electron neutrino, conserving charge and lepton number

beta dacay(neutron->proton) : udd→uud+e−+νe¯

that's what turns a neutron into a proton, it's not some kind of ejection of an electron out of the neutron, but a genuine transmutation of a fundamental particle, a down quark, through the weak force

oh, at this step, since a neutron is composed of three valence quarks {u,d,d} while a hydrogen atom is made out of {u,u,d,e−}, you might be tempted to think that a neutron is also a bound state of an electron and a proton because a neutron can decay into an electron and a proton and the neutron is also slightly more massive than a proton .... right ? [u]again N_O!!!!![/u], they are very different, referring to different length scales and energy scales

e.g.

  • hydrogen atom, 1 proton, 1 electron: {u,u,d,e−}, it's a proton with an electron orbiting around it, it's stable and the size of the hydrogen atom is about 10^−10 meters, and it's bound by the electromagnetic force
  • neutron particle, composed of three valence quarks {u,d,d}, it decays into 1 proton, 1 electron, 1 anti-neutrino, it's not stable, the lifetime of a neutron is just 15 minutes outside the atom, the size of a neutron is about 10^−14 meters, and a neutron is bound by the strong force, quarks and gluons

oh, and ... about the beta decay ... what would happen if ... a hydrogen atom ... absorb an anti-neutrino ? would you say ... changed into neutron? again N_O! but the inverse beta decay makes sense to describe the process of electron capture, where a nucleus which is proton rich absorbs one of the inner orbit electrons and transforms into another element, but It can't happen with lighter elements like hydrogen because it isn't energetically favourable

no doubt, that's a true kind of magic X____X

what is magic ?

Indistiguishable from any sufficiently advanced technology

AWOL: Indistiguishable from any sufficiently advanced technology

well ... about the inverse beta decay ... H+ν¯e→n is possible in the theory it can conserve { energy, momentum, all quantum numbers }, therefore "OK", but .... but .... there are also good reasons it will never be observe: one of the reactants is a neutrino, and the beams are not available in the lab and the cross section is so much tiny that seeing a resonance at the neutron energy is a dream

ah, physics ...

The realm of things you consider magic is inversely proportional to the realm of things you understand.

Some people enjoy existences full of magic.

Yet another kind of magic

AWOL: Yet another kind of magic

Wonderful

...R

INTP:
The realm of things you consider magic is inversely proportional to the realm of things you understand.

exactly, we don’t know the world we live in
and we don’t know about gravitons and gravity at all

a lot of questions are still unanswered

even Einstein was not able to fully explain things without using a trampoline and a bowling ball, which was his attempt to explain the gravity like a funny effect of being a massive mass, therefore we don’t know WHY the energy is converted into mass, we have a theory about it (Higgs effect), we don’t know about gluons, we have described the beta decay like a “transmutation”, we don’t know about the inverse beta decay, we don’t know about neutrino (and to stop them we need a very massive wall made of lead, say … long no less than 1 year light … who is able to build it on the Earth planet? and how much does it cost?), we don’t know about dark matter, we don’t know about singularities (extreme massive gravity conditions, black holes)

etc etc etc

we are able to observe gravitation waves from a binary system (when two extra big stars spin around), but oh, after a few centuries after Newton we are still unable to describe why an apple falls down the tree, or why the white rabbit tumbles down the hole

we know it’s the gravity, and what is the gravity?

is it the gravity force produced by the whole mass of the Earth planet?
AhAhAh, happy to know that a portable electromagnet can win the gravity force quite easily

do we know why? why is it so weak? we don’t =’(

Some people enjoy existences full of magic.

well, the beta decay of a neutron into a proton is defined like
a genuine transmutation of a fundamental particle …

doesn’t “transmutation” (it’s the exact scientific term) sound like …

a___l___c___h___e___m___y

yes/no/maybe ?!?

according to its definition, alchemy is a philosophical and proto-scientific tradition
(practiced throughout Europe, Egypt and Asia)
which aimed to purify, mature, and perfect certain objects
which implies the need to improve the knowledge of the matter

and what are we trying to do in physics? in our collision experiments?
aren’t we improving our knowledge about the matter and equipment
in order to purify, mature, and perfect those “transmutations”
to bend the matter to our wishes? oh …

and we’d better(1) collide electrons instead of protons
because a proton is composed by quarks, whereas an electron is not divisible
we don’t build electron-colliders simply because we can’t build it

an electrons-collider should be a linear collider, not a ring like the LHC (protons-collider)
therefore it should be a 100Km linear long machine: and we can’t build such a machine

anyway, we can have more fun in gamma-gamma physics
happy to see what happens when
two (gamma ray radiation) photons collide each other
and two massive particles arise up from the sub-world

photons with no mass collide ----> something happens ----> mass particles arise up

that’s Alchem-----ohhhhh, shocked X______________X

p.s.
(1) we can’t accelerate electrons in a ring because of the cyclotron radiation
in short because we loose a lot of energy to bend their trajectories
(though a lot of electromagnets along the ring)
with protons is acceptable whereas with electrons it is not

AWOL: Yet another kind of magic

that's the soundtrack of this topic approved :D :D :D :D :D

...and the lead guitarist is an astrophysicist.

AWOL: ...and the lead guitarist is an astrophysicist.

and it will be a success !!!

I know a rock group wanted to put physics in their lyrics therefore they do physics on the stage and you do physics when you listen to their rock n roll


it will take a century to be familiar with the modern physics that is my conclusion


I have a sexy shop (well, it's my girlfriend's property), and a job contract (collaborations) like freelancer, in the spare time I also play like fitness trainer (at a local swimming pool), but it's not a serious job, it was something I did when I was a student and it helped to pay the bills, anyway I find less difficulties talking about plastic toys and muscles compared to the difficulties we have talking about physics, even at CERN, where math is the spoken language

oh, my math and my knowledge are reduced to the ability to provide them the requested electronics circuits (I have a few skills in my CV, from a job in avionics, and they need people skilled in radiation hardening) with a few degree of freedom, formally I am more a mere executor, but I can do physics during the coffee break, talking with those scientists ( hApPy because I studied QEM when I was a student )

but we all love lock n roll, it's the universal language, and my girl friend's hipster trousers are too cute :D

dally:
but we all love lock n roll, it’s the universal language, and my girl friend’s hipster trousers are too cute :smiley:

… i can’t understand you .

Yea.. Quarks.. The come into are country, we don't know what they are doing.... The might kill people. Let's keep them out till we figure out what the hell is going on.

Physisists: NO QUARKS

Qdeathstar: Yea.. Quarks.. The come into are country, we don't know what they are doing.... The might kill people. Let's keep them out till we figure out what the hell is going on.

Physisists: NO QUARKS

Yep. Send them back to Quarkia!!!

dally: ...

p.s. (1) we can't accelerate electrons in a ring because of the cyclotron radiation in short because we loose a lot of energy to bend their trajectories (though a lot of electromagnets along the ring) with protons is acceptable whereas with electrons it is not

Mass has its uses.

I don't quite get chromodynamics, but I put some effort into learning how to think about qed. Enough so that I can do mindless magic calculations anyway. But wasn't much connection between the calculations and anything observable until I learned that X________X'

ain't the same as

X
 \           /
  \         /
   ~~~~~~~~~
  /         \
 /           \
              X´.

Then it all balanced. I don't know what it means, but the calcs come out right.

Hi, Question, we are on Earth orbiting the Sun.

We see light from the Sun 8minutes after it leaves the Sun.

You all still with me? ? ? Okay

If the Sun was to instantly disappear, (not a silly question, lots of questions like this get asked in the science world).

We would know about it 8minutes later. (no heap big light in the sky.)

The gravitational field of the Sun has also instantly disappeared.

When does the Earth and the other orbiting objects start moving off at a tangent to their orbit?(Sort of tangent cos their moons will still be orbiting their planets)

How fast is a gravity wave?

Tom... :)

How fast is a gravity wave?

Speed of light.

But the moon pulling the Earth's oceans involves a lag time so therefore the speed of gravity is water :)

INTP: But the moon pulling the Earth's oceans involves a lag time so therefore the speed of gravity is water :)

What is lagging?

The earth is spinning faster than the moon orbits it. And that orbit is elliptical.