The production and decay of new possible heavy Majorana neutrinos are analyzed in hadronic collisions. New bounds on the mixing of these particles with standard neutrinos are estimated according to a fundamental representation suggested by grand unified models. A clear signature for these Majorana neutrinos is given by same-sign dileptons plus a charged weak vector boson in the final state. We discuss the experimental possibilities for the future Large Hadron Collider (LHC) at CERN.Comment: Latex2e(epsfig), 12 pages, 8 figures, to appear Physical Review

We discuss the possibility of same-sign dileptons as a signature for Majorana neutrinos. The production mechanism is given by a single heavy neutrino production and decay pp −→ l ± N X −→ l ± l ± X ′ . Cross section and distributions are presented for the LHC energies.

Experimental evidence for the existence of orbitally excited B meson states is presented in an analysis of the Bπ and B∗π distribution of View the MathML source using Z0 decay data taken with the DELPHI detector at LEP. The mean Q-value of the decays B∗∗ → B(∗)π is measured to be 284 ± 5 (stat.) ± 15 (syst.) MeV/c2, and the Gaussian width of the signal is 79 ± 5 (stat.) ± 8 (syst.) MeV/c2. This signal can be described as a single resonance of mass m = 5732 ± 5 (stat.) ± 20 (syst.) MeV/c2 and full width Γ = 145 ± 28 MeV/c2. The observed shape is also consistent with the production of several broad and narrow states as predicted by the quark model and partly observed in the D-meson sector. The production rate of B∗∗ per b-jet is found to be 0.27 ± 0.02 (stat.) ± 0.06 (syst.)

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We discuss the production and decay of possible new heavy leptons in some extensions of the standard model. We present a comparison between models and the recent results from the CERN e + e -collider LEP and analyze the most reliable signatures for heavy leptons in the reaction e + e P -I L . A clear separation among models and masses can be done using a Monte Carlo reconstruction of the events.