Recent Tests of QCD at SLD

Abstract

We present selected results on strong interaction physics from the SLD experiment at the SLAC Linear Collider. We report on several new studies of 3- and 4-jet hadronic Z decays, in which jets are identified as quark, antiquark or gluon. The 3-jet Z^0->b\bar{b}g rate is sensitive to the b-quark mass; prospects for measuring m_b are discussed. The gluon energy spectrum is measured over the full kinematic range, providing an improved test of QCD and limits on anomalous bbg couplings. The parity violation in Z^0->b\bar{b}g decays is consistent with electroweak theory plus QCD. New tests of T- and CP-conservation at the bbg vertex are performed. A new measurement of the rate of gluon splitting into b\bar{b} pairs yields g_{b\bar{b}}=0.0031+-0.0007(stat.)+-0.0006(syst.) (Preliminary). We also present a number of new results on jet fragmentation into identified hadrons. The B hadron energy spectrum is measured over the full kinematic range using a new, inclusive technique, allowing stringent tests of predictions for its shape and a precise measurement of <x_B>=0.714+-0.005(stat.)+-0.007(syst.) (Preliminary). A detailed study of correlations in rapidity y between pairs of identified pions, kaons and protons confirms that strangeness and baryon number are conserved locally, and shows local charge conservation between meson-baryon and strange-nonstrange pairs. Flavor-dependent long-range correlations are observed for all combinations of these hadron species, yielding new information on leading particle production. The first study of correlations using rapidities signed such that y>0 corresponds to the quark direction provides additional new insights into fragmentation, including the first direct observation of baryon number ordering along the q\bar{q} axis.

20 pages, 12 figs.; talk given at the QCD99 meeting, Montpellier, France, 7-13 July, 1999; a smaller-print version will appear in the proceedings

References in corpus (5)

• Do the quark masses run? Extracting $m_b(m_Z)$ from LEP data
• Next-to-Leading Order QCD Corrections to Three-Jet Cross Sections with Massive Quarks
• Next-to-Leading-Order Corrections to the Production of Heavy-Flavour Jets in e+e- Collisions
• Next-to-Leading Order QCD Corrections and Massive Quarks in $e^{+}{e}^{-}\to 3$ Jets
• Next-to-Leading-Order Corrections to Momentum Correlations in $Z^0\to b\bar{b}$

Cited by in corpus (3)

• Angular correlations measured in pp collisions by ALICE at the LHC
• Two-particle angular correlations in pp collisions recorded with the ALICE detector at the LHC
• Rapidity-Alignment and p_T Compensation of Particle Pairs in Hadronic Z0 Decays