7,257 research outputs found

    Delta G(x) from high p_t hadrons in DIS at a polarised HERA

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    We investigate the possibility to identify photon-gluon fusion (PGF) events in polarised deep inelastic ep scattering, assuming the kinematics of the HERA collider, by a pair of charged high p_t particles. In a Monte Carlo study we find possible selection criteria and show the expected measurable asymmetries. We discuss the sensitivity to ΔG(x)\Delta G(x) and compare the result to the one obtained using di-jets to tag PGF events.Comment: 8 pages, 5 figures, Contributed paper to the Proceedings of the Workshop on Physics at HERA with Polarized Protons and Electron

    The polarised gluon density Delta G(x) from di-jet events at high energy ep-colliders

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    We present the potential to determine the polarised gluon density from boson-gluon fusion processes with di-jet events at future high energy ep-colliders. These include HERA at DESY operated with polarised electrons and protons, polarised protons from HERA colliding on polarised electrons from a future linear collider, and polarised protons from RHIC at BNL colliding on electrons from a future electron accelerator.Comment: 5 pages, 7 figures, Invited talk presented at the ``International Workshop on the Spin Structure of the Proton and Polarized Collider Physics'', ECT, Trento, Italy, July 23-28, 200

    The polarised gluon density from di-jet events in DIS at a polarised HERA

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    We present a possible direct measurement of the polarised gluon density ΔG(x)\Delta G(x) in LO from di-jet production in polarised deep inelastic ep scattering, assuming the kinematics of the HERA collider. We show the sensitivity to the x-dependence of ΔG(x)\Delta G(x) and to the first moment ∫ΔG(x)dx\int \Delta G(x) dx in the range 0.002<x<0.20.002< x <0.2, assuming the electron and proton beam of HERA being polarised to 70% and an integrated luminosity of at least 200 pb−1^{-1}. We include in our study hadronisation and higher order effects, as well as realistic detector smearing and acceptance. We find that the statistical and systematic uncertainties are small enough to distinguish between different parametrizations for ΔG(x)\Delta G(x), which all are in accordance with present data. We stress that at HERA an x-range could be measured, that is not accessible to any other present or proposed experiment.Comment: 15 pages, 9 figures, Contributed paper to the Proceedings of the Workshop on Physics at HERA with Polarized Protons and Electron

    Predictions for the γγ\gamma \gamma total cross-section in the TeV region: an update

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    In this talk we present an update of model predictions for the γγ\gamma \gamma total cross-section in the TeV region. The update includes preliminary results for γγ\gamma \gamma cross-sections using the Bloch-Nordsieck model for the overlap function of the partons in the transverse space, use of the CJLK parametrisation of the photonic parton densities that has recently become available and extension to the higher γγ\gamma \gamma energies relevant to the planned CLIC collider.Comment: Talk presented by A. De Roeck at the International Linear Collider Workshop, Jeju Island, Aug. 26-30,2002. To appear in the proceedings. 10 pages, LaTeX file, requires A4.sty, four figure

    Total Cross-Sections : Cross-Talk between HERA, LHC and LC

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    We discuss the need to compare total cross-section measurements at LHC and HERA with each other and with available models in order to obtain a more precise prediction of the total hadronic cross-section at the future Linear Collider, thus leading to a better estimate of the hadronic background.Comment: 5 pages, three figures, Talk presented by G. Pancheri at the International Linear Collider Workshop, Paris, April, 200

    Implications of initial LHC searches for supersymmetry

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    13 pĂĄginas, 7 figuras, 1 tabla.-- El Pdf del artĂ­culo es la versiĂłn pre-print: arXiv:1102.4585v1.-- et al.The CMS and ATLAS Collaborations have recently published the results of initial direct LHC searches for supersymmetry analyzing ∌35/pb of data taken at 7 TeV in the centre of mass. We incorporate these results into a frequentist analysis of the probable ranges of parameters of simple versions of the minimal supersymmetric extension of the Standard Model (MSSM), namely the constrained MSSM (CMSSM), a model with common non-universal Higgs masses (NUHM1), the very constrained MSSM (VCMSSM) and minimal supergravity (mSUGRA). We present updated predictions for the gluino mass, m[(g)\tilde]mg, the light-Higgs boson mass, M h , BR(B s →Ό + ÎŒ −) and the spin-independent dark matter scattering cross section, sSIppSI. The CMS and ATLAS data make inroads into the CMSSM, NUHM1 and VCMSSM (but not mSUGRA) parameter spaces, thereby strengthening previous lower limits on sparticle masses and upper limits on sSIppSI in the CMSSM and VCMSSM. The favoured ranges of BR(B s →Ό + ÎŒ −) in the CMSSM, VCMSSM and mSUGRA are close to the Standard Model, but considerably larger values of BR(B s →Ό + ÎŒ −) are possible in the NUHM1. Applying the CMS and ATLAS constraints improves the consistency of the model predictions for M h with the LEP exclusion limits.This work was supported in part by the European Community’s Marie-Curie Research Training Network under contracts MRTN-CT-2006-035505 ‘Tools and Precision Calculations for Physics Discoveries at Colliders’ and MRTN-CT-2006-035482 ‘FLAVIAnet’, and by the Spanish MEC and FEDER under grant FPA2005-01678. The work of S.H. was supported in part by CICYT (grant FPA 2007–66387 and FPA 2010–22163-C02-01), and the work of K.A.O. was supported in part by DOE grant DE–FG02–94ER– 40823 at the University of Minnesota. K.A.O. also thanks SLAC (supported by the DOE under contract number DE-AC02-76SF00515).Peer reviewe

    SASICE: Safety and sustainability in civil engineering

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    The performance of the built environment and the construction sector are of major importance in Europe’s long term goals of sustainable development in a changing climate. At the same time, the quality of life of all European citizens needs to be improved and the safety of the built environment with respect to man-made and natural hazards, such as flooding and earthquakes, needs to be ensured. Education has a central role to play in the transformation of a construction sector required to meet increasing demands with regard to safety and sustainability. In this work, the SASICE project is presented. The aim of this project is to promote the integration of safety and sustainability in civil engineering education. The project is organised in the context of the Lifelong Learning Programme, funded by the European Community. The coordinator organisation is the University of Bologna. Nine partner universities from different countries are involved in this transnational project. The universities participating to the project constitute a network of high level competences in the civil engineering area, with several opportunities to improve lifelong learning adopting different media: joint curricula, teaching modules and professor and student exchanges. As a response to the challenge regarding new educational methods in sustainable engineering, teaching modules are developed in 4 thematic areas: (1) Safety in construction, (2) Risk induced by Natural Hazards Assessment, (3) Sustainability in construction, and (4) Sustainability at the territorial level. The development of the teaching modules is based on an extensive analysis of the need for highly qualified education on Safety and Sustainability involving all relevant stakeholders (European and national authorities, companies, research institutes, professional organizations, and universities).The main target is enabling students to introduce these advanced topics in their study plans and curricula and reach, at the end of their studies, a specific skill and expertise in safety and sustainability in Civil Engineering. With our natural resources fading away and our infrastructure in dire need of repair, new trends and challenges in civil engineering education in the concept of “Sustainable Development” are needed to be adressed.<br/

    Derivation of some translation-invariant Lindblad equations for a quantum Brownian particle

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    We study the dynamics of a Brownian quantum particle hopping on an infinite lattice with a spin degree of freedom. This particle is coupled to free boson gases via a translation-invariant Hamiltonian which is linear in the creation and annihilation operators of the bosons. We derive the time evolution of the reduced density matrix of the particle in the van Hove limit in which we also rescale the hopping rate. This corresponds to a situation in which both the system-bath interactions and the hopping between neighboring sites are small and they are effective on the same time scale. The reduced evolution is given by a translation-invariant Lindblad master equation which is derived explicitly.Comment: 28 pages, 4 figures, minor revisio
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