17,429 research outputs found

    Status of SM calculations of b > s transitions

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    We report recent progress in SM calculations of bsb \to s transitions. We discuss the first NNLL prediction of the BˉXsγ\bar B \to X_s \gamma branching ratio, including important additional subtleties due to non-perturbative corrections and logarithmically-enhanced cut effects, and also recent results on the inclusive mode BˉXs+\bar B \to X_s \ell^+ \ell^-. Moreover, new results on the corresponding exclusive modes are reviewed. Finally, we comment on the present status of the so-called BKπB \to K \pi puzzle in hadronic bsb \to s transitionsComment: 10 pages, 6 figures, minor changes, published versio

    The Structure of Quasi-Real and Virtual Photons

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    This review covers the measurements of the QED and QCD structure of quasi-real and virtual photons from the reaction ee --> ee gamma* gamma(*) --> ee X.Comment: Invited talk given at the PHOTON 99 Conference, Freiburg, Germany, May 1999, to appear in the Proceeding

    LEP Tunnel Cross-section

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    Proposal to establish a Sponsoring Consortium for Open Access Publishing in Particle Physics

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    In the present proposal, the publishers' subscription income from multiple institutions is replaced by an "author-side" funding. Journals are paid through contracts between publishers and a single financial partner, the "Sponsoring Consortium for Open Access Publishing in Particle Physics" (SCOAP3). SCOAP3 is envisioned as a global network of funding agencies, research laboratories, and libraries that will contribute the necessary funding; each SCOAP3 partner will recover its contribution from the cancellation of journal subscriptions. This model avoids the obvious disadvantage of authors being directly charged for the OA publication of their articles, which is perceived as an even higher barrier than subscription charges, in particular for theoretical physicists from small institutions who account for the vast majority of HEP papers. The financing and governance of SCOAP3 will follow as much as possible the example of the memoranda of understanding governing large research collaborations. Its partners will contribute on a pro-rata basis according to the number of scientific publications from their country or laboratory in a reference period

    Final LHC Synchronization Test a Success

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    Geneva, 25 August 2008. CERN has today announced the success of the second and final test of the Large Hadron Collider’s beam synchronization systems which will allow the LHC operations team to inject the first beam into the LHC. Friday evening 22 August, a single bunch of a few particles travelled down the transfer line from the Super Proton Synchrotron (SPS) accelerator to the LHC. After a period of optimization, one bunch was kicked up from the transfer line into the LHC beam pipe and steered counter-clockwise about 3 kilometres around the LHC. “Thanks to a fantastic team, both the clock-wise and counter-clockwise tests went without a hitch. We look forward to a resounding success when we make our first attempt to send a beam all the way around the LHC,” said Lyn Evans, LHC Project Leader. Both the counter-clockwise and clockwise tests are part of the preparations to ready the LHC, the world’s most powerful particle accelerator, for the eventual acceleration and collision of two beams at an energy of 5 TeV per beam. This unprecedented event is foreseen to take place by end 2008

    Electricity-assisted production of caproic acid from grass

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    Background: Medium chain carboxylic acids, such as caproic acid, are conventionally produced from food materials. Caproic acid can be produced through fermentation by the reverse beta-oxidation of lactic acid, generated from low value lignocellulosic biomass. In situ extraction of caproic acid can be achieved by membrane electrolysis coupled to the fermentation process, allowing recovery by phase separation. Results: Grass was fermented to lactic acid in a leach-bed-type reactor, which was then further converted to caproic acid in a secondary fermenter. The lactic acid concentration was 9.36 +/- 0.95 g L-1 over a 33-day semi-continuous operation, and converted to caproic acid at pH 5.5-6.2, with a concentration of 4.09 +/- 0.54 g L-1 during stable production. The caproic acid product stream was extracted in its anionic form, concentrated and converted to caproic acid by membrane electrolysis, resulting in a >70 wt% purity solution. In a parallel test exploring the upper limits of production rate through cell retention, we achieved the highest reported caproic acid production rate to date from a lignocellulosic biomass (grass, via a coupled process), at 0.99 +/- 0.02 g(-)L(-1) h(-1). The fermenting microbiome (mainly consisting of Clostridium IV and Lactobacillus) was capable of producing a maximum caproic acid concentration of 10.92 +/- 0.62 g L-1 at pH 5.5, at the border of maximum solubility of protonated caproic acid. Conclusions: Grass can be utilized as a substrate to produce caproic acid. The biological intermediary steps were enhanced by separating the steps to focus on the lactic acid intermediary. Notably, the pipeline was almost completely powered through electrical inputs, and thus could potentially be driven from sustainable energy without need for chemical input

    Spectroscopy with Hadrons Beams at COMPASS

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    Following numerous interactions with the SPSC in 2007 we review projected capa- bilities of the COMPASS spectrometer in the field of light hadron spectroscopy. The paper describes in detail a full simulation with subsequent partial wave analysis of two final states for central production. Both, neutral and all charged states can very well be observed and analyzed within COMPASS. In addition we show the result of a full partial wave analysis of data taken in the pilot run 2004 using the diffractively produced π+ππ\pi^+\pi^-\pi^- final state. The results agree remarkably well with previous data taken an BNL. We also vaticinate the physics data sample expected for 2008, using projected beam times for different reaction mechanisms
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