[en] The authors present recent D0 results based on approximately 1 fb^-1 of p(bar p) collisions at √s = 1.96 TeV recorded at the Fermilab Tevatron. Preliminary results on a search for the flavor changing neutral current process D⁺ → π⁺μ⁺μ^-, a measurement of the Cp violation parameter in B mixing, ε_B, and a two sided limit on the B_s oscillation frequency Δm_s are presented. The limits on ε_B and Β(D⁺ → π⁺μ⁺μ^-) are the world's best limits. The two sided bound on Δm_s is the first direct indication by a single experiment that Δm_s is bounded from above

[en] The most recent achievements of the analysis of the data collected by the OBELIX experiment at LEAR are presented. The most interesting results concern the apparent OZI-rule violation in some annihilation channels and the consequent explanation in terms of a polarized ($\text{s}\text{s}$) strangeness content of the nucleon, a further convincing evidence for the presence of two pseudoscalar states in the $\text{E}\text{ι}$ region and finally the observation of a tantalizing anomaly in the total antineutron-proton cross section at very low momenta.

[en] We present the observation of doubly produced J/ψ mesons as an example of processes containing a substantial fraction of double parton scattering. Measurements of the production cross sections for singly and doubly-produced J/ψ mesons were done with the D0 detector at Fermilab in pp̄ collisions at √s = 1.96 TeV with an integrated luminosity of 8.1 fb"−"1. For the first time, the double J/ψ production cross section is separated into two parts: contributions from both single and double parton scattering. Lastly, this separation allowed us to determine the effective cross section σ_e_f_f, a parameter related to the parton spatial density inside the hadron.

[en] The results of a spin-parity analysis of n(bar sign)p annihilation in the channels with 3 and 5 charged pions are presented. In the former case, the analysis suggests the existence of two resonances with quantum numbers 0++ and 2++ around 1500-1550 MeV/c2; in the latter case, the presence of a broad resonance at about 1350 MeV/c2 decaying dominantly the ρρ is confirmed, but a great amount of ρσ(1--) nonresonant background is required

[en] The eight layer, 750 k channel CDF Run II silicon detector is an essential part of the heavy flavor tagging and forward tracking capabilities of the CDF experiment. A summary of the experience in commissioning and operating this double sided silicon detector during the first 2 years of Run II is given

[en] Neutrinos are elementary particles with no electric charge, no magnetic moment, half integral spin and a small but non-zero mass. Being electrically neutral, neutrinos rarely interact with matter via weak force. In this work, we study charged current anti-neutrino - nucleus (¹²C) QES. To describe CCQES, we use the Llewellyn Smith (LS) model. For incorporating the nuclear effects, we use the Fermi gas model along with Pauli suppression condition. We calculate ν-bar_μ ¹²C CCQES differential and total cross sections for different values of axial mass M_A and compare the results with experimental data, with the goal of finding the most appropriate M_A value

[en] Ten years ago, in May 1983, the UA1 experiment led by Carlo Rubbia at CERN's proton-antiproton collider saw the first Z particle, the heavy (91 GeV) electrically neutral carrier of the weak force. The press announced the discovery of 'heavy light', a highly apt description which has unfortunately fallen into disuse. The weak force comes in two varieties - one which permutes electric charges (the classic example being the beta decay of a neutron into a proton and an electron), and a neutral variant which does not. Each has its carrier particle, and both were discovered at CERN - first the charged W, in January 1983, and then the Z, a few months later. For both experiment and theory, the Z discovery was the culmination of a long and diligent quest without parallel in the history of modern physics. The missing piece of the 'electroweak' jigsaw finally clicked into place, and for ever after electromagnetism would be firmly linked with the weak nuclear force. It was the twentieth-century remake, with a much bigger cast, of the story which began in 1864 when James Clerk Maxwell wrote down his four famous equations linking electricity and magnetism. This was the birth of a new science - electromagnetism

[en] The hypothetic R-resonance production (anomalous 'll-barγγ' events at LEP) with 60 GeV mass at FNAL hadron collider has been considered. The cross-section of this R-resonance production with the consequent decay R → γγ is obtained. Various distributions of leptons and photons in the process pp-bar → ll-bar R (→ γγ) X are calculated. 13 refs

[en] The combined 1993, 1994, and 1995 data from the LSND experiment shows a statistically compelling excess of events of the type expected for anti ν_μ → anti ν_e neutrino oscillations. An electron between 36 and 60 MeV is identified by Cherenkov and scintillation light from anti ν_ep → e⁺n and if a γ is tightly constrained to be correlated with it from np → dγ (2.2 MeV), then 22 such events are observed, but only 4.6 ± 0.6 are expected from backgrounds. The probability that this is a fluctuation is < 10^-7. If subsequent analysis shows a similar effect from the independent channel ν_μ → ν_e, then this would imply a neutrino mass difference which would contribute significantly to the dark matter of the universe. Explaining also the solar and atmospheric neutrino deficits results in a neutrino mass pattern which gives a cold and hot dark matter mix which fits the structure of the universe on all scales and requires a critical density universe and a universe age compatible with that of the oldest stars. This mass pattern involves a sterile neutrino, evidence for which may come from the need for it in producing heavy elements by supernovae and for blowing off the supernova mantle. (orig.)

[en] In 1995 two international teams demonstrated the existence of the quark top, the sixth and last of the standard model accepted by most particle physicists. A group of CEA scientists participated in one of the two experiments that enabled this discovery in the Fermi laboratory. The standard model and the theory of quarks is briefly reviewed and detection methods, the d-zero (d-0) detector and Tevatron experiments are described. (C.B.)