The DØ Collaboration has studied for the first time the properties of hadron-collider jets reconstructed with a successive-combination algorithm based on relative transverse momenta (k⊥) of energy clusters. Using the standard value D=1.0 of the jet-separation parameter in the k⊥ algorithm, we find that the pT of such jets is higher than the ET of matched jets reconstructed with cones of radius R=0.7, by about 5 (8) GeV at pT~90 (240) GeV. To examine internal jet structure, the k⊥ algorithm is applied within D=0.5 jets to resolve any subjets. The multiplicity of subjets in jet samples at (s)=1800 GeV and 630 GeV is extracted separately for gluons (Mg) and quarks (Mq), and the ratio of average subjet multiplicities in gluon and quark jets is measured as (<Mg>-1)/(<Mq>-1)=1.84+/-0.15 (stat)+/-0.220.18 (syst). This ratio is in agreement with the expectations from the HERWIG Monte Carlo event generator and a resummation calculation, and with observations in e+e- annihilations, and is close to the naive prediction for the ratio of color charges of CA/CF=9/4=2.25.
Physical Review D
- Pub Date:
- March 2002
- Experimental tests;
- Light quarks;
- High Energy Physics - Experiment
- Submitted to Phys.Rev.D. 24 pages, 31 figures. Updated references, minor text changes