1. May 8, 2007

### neu

Dominant decays of W/Z bosons are quark aintiquark pairs which decay into jets of hadrons.

But how can a quark decay into a hadron?

Surely as hadrons are bound states of quarks then hadrons are heavier and so quark->hadrons violates mass conservation (energy conservation).

I know i'm wrong but i can't see why.

what am I missing?

2. May 8, 2007

### studnte

the process of quark->hadron is called fragmentation/hadronization. this precess is complicated. basically, there are three models: string fragmentation, independent fragmentation and cluster fragmentation. for string fragmentation, the basic idea is: two quark-anit quark connected by
a string(because colour flux), the string carries energy(1 GeV/fm).as the quark-anti quark move apart, the potential energy stored in string increases, and then the string may break down then another two pair quark-anti quark are generated. (just image a string is break, and then a new pair quarks are generated at the each end of new string), this process recycled untile on-mass shell hadrons remain. so this hadron corresponding to a small piece of string with two quarks at each of end the string. these hadrons are mostly pions. this ideal also is called lund model

but i am not a theorist and maybe there are some misunderestanding

3. May 11, 2007

### ihtw

Another way to think of this is to consider the electromagnetisim. Atoms tend to be neutral instead of being charged.

The only stable particle charged under strong force is color-singlet. Quarks carry color (the "charge" for strong force), r/g/b. one quark cannot be color-singlet. You have to take several quarks together, to make their colors "cancel" each other.