Quark-antiquark creation in strong interactions

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sunrah
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(please note this is similar to a homework question I have posted but it is not the same and here I am just trying to understand a concept)

In a book I was reading it said

[itex] \Delta^{+} \longrightarrow n + \pi^{+}[/itex]

is a viable process via the strong force because all that is needed is a down antidown quark pair, which can be provided via the strong force. My question is why? If [itex]\Delta^{+}[/itex] is uud and [itex]\Delta^{+}\pi^{+}[/itex] is udd + [itex]u\bar{d}[/itex] we can see that the right hand side only has one antidown quark therefore there has only been one quark-antiquark pair created. Converting one quark into two only creates one extra particle effectively so I see a deficit on the left hand side.

Please can someone explain
 
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Bill_K said:
:confused: What you have written does not conserve charge.

You're right. I've changed it now it. My question really is about how a 3 quark particle can become two particles with a total of 5 quarks :smile:

we don't do this stuff in lectures
 
The process would be

d -> d + g -> d + (q qbar)

A gluon gets emitted that then decays. You're thinking its one d decaying to two, when its really 1 to 3
 
Hepth said:
The process would be

d -> d + g -> d + (q qbar)

A gluon gets emitted that then decays. You're thinking its one d decaying to two, when its really 1 to 3

oh I see. does the q-qbar-pair have to be the same type? If I understand it right in this case the gluon must become an up and an antidown pair.
 
Hepth said:
The q can be anything, but not mixed. A pi0 is not u dbar. It is u ubar and d dbar.

sorry my question was wrong. it should have been pi+ :redface:

does this mean this process is forbidden?
 
I'll write ubar as u~

You have
uud > udd + ud~
So quark content is fine.

Draw it out, the gluon makes a d d~ but the d goes to the neutron, the d~ to the pion.
 
I think it just went click.
The Delta+ decays into two parts (e.g. ud and u) thereby producing a gluon which becomes dd~ pair except the d is taken up by ud to form a neutron and d~ joins with u to form a pi+.

Is that more or less right?