The First Year at LHC: Diffractive Physics

At the LHC, diffractive physics will be explored by the dedicated experiment TOTEM whose Technical Design Report has been approved in Summer 2004. The experimental programme will be carried out partly in TOTEM standalone mode for purely forward phenomena like elastic scattering, and partly in collaboration with CMS for processes requiring a full rapidity coverage. ATLAS and ALICE are interested in diffraction for a later stage. This article presents the TOTEM/CMS running scenario for diffractive physics in the first year of LHC. We discuss which processes are within reach and with which statistics they can be measured.Comment: 11 pages, 7 figures; proceedings of "Physics at LHC", July 2004, Vienna; to be published in a supplement of the Czechoslovak Journal of Physic

Fluorescence study on rat epithelial cells and liposomes exposed to aromatic nitroxides

This study was performed to evaluate the effects, if any, of aromatic nitroxides, namely, indolinic nitroxides, on membrane fluidity of rat epithelial cells using steady-state fluorescence. These nitroxides are being increasingly considered as new and versatile compounds to reduce oxidative stress in biological systems. Hence, the results obtained in this study will give more insights on the interaction of these compounds with biological structures which at present is lacking, especially in view of their possible application as antioxidant therapeutic agents. The probes DPH and Laurdan which give information on the hydrophobic and hydrophilic-hydrophobic regions of the membrane bilayer, respectively, showed that nitroxide 1 (1,2-dihydro-2-methyl-3H-indole-3-one-1-oxyl) significantly increases membrane fluidity, whereas the corresponding phenylimino nitroxide derivative 2 (1,2-dihydro-2-methyl-3H-indole-3-phenylimino-1-oxyl) leads to membrane rigidification. The aliphatic nitroxide TEMPO included in this study for comparison produced no modifications. Consequently, it appears that the structure of the heterocyclic rings (aromatic or aliphatic) and the substituents may affect membrane fluidity differently. (C) 2004 Elsevier Inc. All rights reserved

Interference Study of the chi_c0 (1^3P_0) in the Reaction Proton-Antiproton -> pi^0 pi^0

Fermilab experiment E835 has observed proton-antiproton annihilation production of the charmonium state chi_c0 and its subsequent decay into pi^0 pi^0. Although the resonant amplitude is an order of magnitude smaller than that of the non-resonant continuum production of pi^0 pi^0, an enhanced interference signal is evident. A partial wave expansion is used to extract physics parameters. The amplitudes J=0 and 2, of comparable strength, dominate the expansion. Both are accessed by L=1 in the entrance proton-antiproton channel. The product of the input and output branching fractions is determined to be B(pbar p -> chi_c0) x B(chi_c0 -> pi^0 pi^0)= (5.09 +- 0.81 +- 0.25) x 10^-7.Comment: 4 pages, 4 figures, Accepted by PRL (July 2003

Precision measurements of the total and partial widths of the psi(2S) charmonium meson with a new complementary-scan technique in antiproton-proton annihilations

We present new precision measurements of the psi(2S) total and partial widths from excitation curves obtained in antiproton-proton annihilations by Fermilab experiment E835 at the Antiproton Accumulator in the year 2000. A new technique of complementary scans was developed to study narrow resonances with stochastically cooled antiproton beams. The technique relies on precise revolution-frequency and orbit-length measurements, while making the analysis of the excitation curve almost independent of machine lattice parameters. We study the psi(2S) meson through the processes pbar p -> e+ e- and pbar p -> J/psi + X -> e+ e- + X. We measure the width to be Gamma = 290 +- 25(sta) +- 4(sys) keV and the combination of partial widths Gamma_e+e- * Gamma_pbarp / Gamma = 579 +- 38(sta) +- 36(sys) meV, which represent the most precise measurements to date.Comment: 17 pages, 3 figures, 3 tables. Final manuscript accepted for publication in Phys. Lett. B. Parts of the text slightly expanded or rearranged; results are unchange

Measurement of the branching fraction and CP content for the decay B(0) -> D(*+)D(*-)

This is the pre-print version of the Article. The official published version can be accessed from the links below. Copyright @ 2002 APS.We report a measurement of the branching fraction of the decay B0→D*+D*- and of the CP-odd component of its final state using the BABAR detector. With data corresponding to an integrated luminosity of 20.4  fb-1 collected at the Υ(4S) resonance during 1999–2000, we have reconstructed 38 candidate signal events in the mode B0→D*+D*- with an estimated background of 6.2±0.5 events. From these events, we determine the branching fraction to be B(B0→D*+D*-)=[8.3±1.6(stat)±1.2(syst)]×10-4. The measured CP-odd fraction of the final state is 0.22±0.18(stat)±0.03(syst).This work is supported by DOE and NSF (USA), NSERC (Canada), IHEP (China), CEA and CNRS-IN2P3 (France), BMBF (Germany), INFN (Italy), NFR (Norway), MIST (Russia), and PPARC (United Kingdom). Individuals have received support from the A.P. Sloan Foundation, Research Corporation, and Alexander von Humboldt Foundation