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I was doing some info gathering for my forum, and found that the mesons consists of quark-antiquark pairing, but i have read that, when a particle comes near to it's antiparticle they annihilate each other, so how can the meson be real?, anyone to help clearing my doubt
Thanks for all the help

Look this link (PDF) for a explanation:

http://www.infn.it/thesis/PDF/482-Cerizza-laurea.pdf


Where do you have found that the mesons consist of quark-antiquark pairing? The meson ?· for example consist of a 25% of (quark top-antiquark top); 25% of (quark down-antiquark down) and for a 50% of (quark strange-antiquark strange); but there are even the vectorial mesons with a mix of (antiquark up-quark strange), (antiquark down-quark strange) and (antiquark strange-quark strange).

Bluespace wrote:I was doing some info gathering for my forum, and found that the mesons consists of quark-antiquark pairing, but i have read that, when a particle comes near to it's antiparticle they annihilate each other, so how can the meson be real?, anyone to help clearing my doubt
Thanks for all the help

Things are by far not as simple. Most mesons are not composed of the SAME type of quarks and anti-qualrs, whence they cannot annihilate. Each quark comes in a particular "flavour" (up, down, strange, charm, beauty, top) , which implies certain conserved quantum numbers that prevent the state to annihilate.

Moreover, besides the socalled /valence/ quark and anti-quark, there is a cloud of gluons as well in each meson. Also within a meson bound state, new quark-antiquark pairs can be created by a pair of gluons besides annihilation.

So there are many such time-dependent quantum fluctuations going on all the time.

Bye Fridger

Fenerit wrote:Where do you have found that the mesons consist of quark-antiquark pairing?

that too was in a pdf i downloaded

The meson ?· for example consist of a 25% of (quark top-antiquark top); 25% of (quark down-antiquark down) and for a 50% of (quark strange-antiquark strange); but there are even the vectorial mesons with a mix of (antiquark up-quark strange), (antiquark down-quark strange) and (antiquark strange-quark strange).

i am not that deep into particle physics, i learn just for fun, so is it that when they combine in small percentage values, the rules of annihilation disappears? because u mentioned above the (quark top-antiquark top) 25%, but isn't it still a particle-antiparticle combination and with the strong force acting wouldn't they turn into pure energy ?

meantime thanks for the link, though it looks to be a lot of equations, but any informations are great, i'll read it tomorow, in hope it will clear everything, it's 00.30 am, zzzzzz

bye thanks again

Fenerit wrote:Look this link (PDF) for a explanation:

http://www.infn.it/thesis/PDF/482-Cerizza-laurea.pdf


Where do you have found that the mesons consist of quark-antiquark pairing? The meson ?· for example consist of a 25% of (quark top-antiquark top); 25% of (quark down-antiquark down) and for a 50% of (quark strange-antiquark strange); but there are even the vectorial mesons with a mix of (antiquark up-quark strange), (antiquark down-quark strange) and (antiquark strange-quark strange).

Fenerit,

let me tell you as a Prof. in Theoretical Particle Physics that this paper is about the entirely different issue of CP violation in weak decays of mesons. This does NOT give an answer whatsoever on Bluespace's question...

Bye Fridger

hi Fridger, your reply came when i was replying to Fenerit

thanks for the help,

also can you help in Fenerit's reply about the percentage value 'combination' ? as he's mentioning the same type of quarks

Bluespace wrote:hi Fridger, your reply came when i was replying to Fenerit

thanks for the help,

also can you help in Fenerit's reply about the percentage values ? as it mentioned the same type of quarks

Fridger, how you can see from the last post, somewhat which concern the CP violation is required. Right, the paper is quicky here, just as link on what about we "normal" people who attempt to speak of mesons can do.

Bluespace wrote:hi Fridger, your reply came when i was replying to Fenerit

thanks for the help,

also can you help in Fenerit's reply about the percentage value 'combination' ? as he's mentioning the same type of quarks

The mixing of the different quark-"flavors" within a particular meson is an involved issue. The ?· and the ?·' (pseudo-scalar) mesons are particularly tricky cases, that need a more thorough discussion for understanding. Vector mesons are much simpler in that respect. They have so-called "ideal" mixings of the involved quark flavours.

In any case that's not a subject one may understand within a few lines of forum discussion

Bye Fridger

GOT IT

More PDF's required

ZZZZZZZzzzzz..............

Fenerit wrote:

Bluespace wrote:hi Fridger, your reply came when i was replying to Fenerit

thanks for the help,

also can you help in Fenerit's reply about the percentage values ? as it mentioned the same type of quarks

Fridger, how you can see from the last post, somewhat which concern the CP violation is required. Right, the paper is quicky here, just as link on what about we "normal" people who attempt to speak of mesons can do.

Because I had a look at it and because I am a Prof. in Particle Physics. What else can I say. The paper describes the CP=T-violating physics of B-meson decays as observed at the BaBar experiment at Slac/California (Stanford!).

Bye fridger

t00fri wrote:
...

In any case that's not a subject one may understand within a few lines of forum discussion

Bye Fridger

Indeed. I ABSOLUTELY agree. Mesons are serious, charmed, things.

Mesons are real, just not for very long. (They are unstable and decay quickly)