Subjet multiplicity of gluon and quark jets reconstructed with the κ algorithm in pp̄ collisions

V. M. Abazov, B. Abbott, A. Abdesselam, M. Abolins, V. Abramov, B. S. Acharya, D. L. Adams, M. Adams, S. N. Ahmed, G. D. Alexeev, A. Alton, G. A. Alves, N. Amos, E. W. Anderson, Y. Arnoud, C. Avila, M. M. Baarmand, V. V. Babintsev, L. Babukhadia, T. C. BaconA. Baden, B. Baldin, P. W. Balm, S. Banerjee, E. Barberis, P. Baringer, J. Barreto, J. F. Bartlett, U. Bassler, D. Bauer, A. Bean, F. Beaudette, M. Begel, A. Belyaev, S. B. Beri, G. Bernardi, I. Bertram, A. Besson, R. Beuselinck, V. A. Bezzubov, P. C. Bhat, V. Bhatnagar, M. Bhattacharjee, G. Blazey, F. Blekman, S. Blessing, A. Boehnlein, N. I. Bojko, F. Borcherding, S. Desai, DØ Collaboration

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34 Scopus citations


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 (κ) of energy clusters. Using the standard value D = 1.0 of the jet-separation parameter in the κ 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 κ 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)±0.18 0.22 (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.

Original languageEnglish (US)
Article number052008
JournalPhysical Review D
Issue number5
StatePublished - 2002


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