Arnold Engler Professor Emeritus Ph.D., University of Berne Email: engler@cmphys.phys.cmu.edu Phone: (412) 268-2777 Fax: (412) 681-0648

Among the most important questions, in physics are the properties and the interactions of the three families of particles. The Colliding Beams group at Carnegie Mellon has over the past 16 years participated in the construction and operation of a giant detector to address this question. This detector, the largest of its kind, is situated at the LEP Collider at CERN, straddling the border between France and Switzerland, near Geneva. The observation that only three particle families exist has been answered by this detector. We have also studied in great detail the properties of the Z^o, the neutral Intermediate Vector Boson.  We have also studied the properties of the charged Intermediate Vector Bosons W⁺ and W^-.  The LEP detector is currently being dismantled to make room for the LHC, a new proton proton collider at CERN to search for the Higgs Boson.  Our group is participating in the design of a new detector to look for the Higgs particle.

Selected Publications

L3 Collaboration -- M. Acciarri et al., "Search for Charginos and Neutralinos in e+e- collisions at Sqrt(s) = 189 GeV," Phys. Lett. B 472 (2000) 420-433.

L3 Collaboration -- M. Acciarri et al., "Search for Excited Leptons at Sqrt(s) = 189 GeV," Phys. Let. B 473 (2000) 177-185.

L3 Collaboration -- M. Acciarri et al., "Measurement of the Probability of Gluon Splitting into Charmed Quarks in Hadronic Z Decays," Phys. Let. B 476 (2000) 243-255.

L3 Collaboration -- M. Acciarri et al., "Direct Observation of Longitudinally Polarised W+- Bosons.," Phys. Let. B 474 (2000) 194-204.

L3 Collaboration -- M. Acciarri et al., Measurement of Hadron and Lepton-Pair Production at 130 GeV < sqrt(s) < 189 GeV at LEP. Phys. Let. B 479 (2000) 101-117.

L3 Collaboration -- M. Acciarri et al., "Measurement of the Effective Weak Mixing Angle by Jet-Charge Asymmetry in Hadronic Decays of the Z Boson," Phys. Lett. B 439, 225 (1998).

L3 Collaboration -- M. Acciarri et al., "Measurement of the Michel Parameters and the Average Tau-Neutrino Helicity From Tau Decays at LEP," Phys. Lett. B 438, 405 (1998).

L3 Collaboration -- M. Acciarri et al., "Measurement of W-Pair Cross Sections in e⁺e^- Interactions at the square root of s = 183 GeV and W-Decay Branching Fractions," Phys. Lett. B 436, 437 (1998).

L3 Collaboration -- M. Acciarri et al., "Measurement of Radiative Bhabha and Quasi-Real Compton Scattering," Phys. Lett. B 439, 183 (1998).

L3 Collaboration -- M. Acciarri et al., "Study of Anomalous ZZ_gamma and Z_{gamma gamma} Couplings at LEP," Phys. Lett. B 436, 187 (1998).

L3 Collaboration -- M. Acciarri et al., "Test of CP Invariance in Z -> mu⁺ mu^- gamma Decay," Phys. Lett. B 436, 428 (1998).

L3 Collaboration -- M. Acciarri et al., "Search for Neutral Higgs Bosons of the Minimal Supersymmetric Standard Model in Interactions at the square root of s = 130-183 GeV," Phys. Lett. B 436, 389 (1998).