I would like to supplement dmckee's answer for completeness, since the «middle» comment might be misinterpreted, it is middle in energy.

One might think that the hadrons are formed centrally or distributed spherically in space, which is not the case. Experimentally the so called leading particle effect dominates the data, and before the advent of QCD gave the parton model proposed by Feynman. The leading partons fragmented into jets defining the direction of the quarks. This leading effect was laboriously reproduced by QCD, laboriously because calculations in QCD are not simple.

This search gives experimental data from the decay of Z into two quarks that shows both the effect and that the jets from the quarks are different depending on the quark type.

Gluon jets were established at PETRA, again collimated hadrons about the jet, and their difference with quark jets studied by DELPHI and OPAL extensively. In fig 2 you can see that the three parton jets, two quarks and the gluon, are separated cleanly.

I would like to supplement dmckee's answer for completeness, since the "middle" comment might be misinterpreted, it is middle in energy.

One might think that the hadrons are formed centrally or distributed spherically in space, which is not the case. Experimentally the so called leading particle effect dominates the data, and before the advent of QCD gave the parton model proposed by Feynman. The leading partons fragmented into jets defining the direction of the quarks. This leading effect was laboriously reproduced by QCD, laboriously because calculations in QCD are not simple.

This search gives experimental data from the decay of Z into two quarks that shows both the effect and that the jets from the quarks are different depending on the quark type.

Gluon jets were established at PETRA, again collimated hadrons about the jet, and their difference with quark jets studied by DELPHI and OPAL extensively. In fig 2 you can see that the three parton jets, two quarks and the gluon, are separated cleanly.

I would like to supplement dmckee's answer for completeness, since the "middle" comment might be misinterpreted, it is middle in energy.

One might think that the hadrons are formed centrally or distributed spherically in space, which is not the case. Experimentally the so called leading particle effect dominates the data  , and before the advent of QCD gave the parton model proposed by Feynman. The leading partons fragmented into jets defining the direction of the quarks. This leading effect was laboriously reproduced by QCD, laboriously because calculations in QCD are not simple.

This search gives experimental data from the decay of Z into two quarks that shows both the effect and that the jets from the quarks are different depending on the quark type.

Gluon jets were established at PETRA, again collimated hadrons about the jet, and their difference with quark jets studied by DELPHI and OPAL extensively. In fig 2 you can see that the three parton jets, two quarks and the gluon, are separated cleanly.

I would like to supplement dmckee's answer for completeness, since the «middle» comment might be misinterpreted, it is middle in energy.

One might think that the hadrons are formed centrally or distributed spherically in space, which is not the case. Experimentally the so called leading particle effect dominates the data, and before the advent of QCD gave the parton model proposed by Feynman. The leading partons fragmented into jets defining the direction of the quarks. This leading effect was laboriously reproduced by QCD, laboriously because calculations in QCD are not simple.

This search gives experimental data from the decay of Z into two quarks that shows both the effect and that the jets from the quarks are different depending on the quark type.

Gluon jets were established at PETRA, again collimated hadrons about the jet, and their difference with quark jets studied by DELPHI and OPAL extensively. In fig 2 you can see that the three parton jets, two quarks and the gluon, are separated cleanly.