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Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAM ; Three-jet production in deep inelastic ep scattering and photoproduction was investigated with the ZEUS detector at HERA using an integrated luminosity of up to 127pb-1. Measurements of differential cross sections are presented as functions of angular correlations between the three jets in the final state and the proton-beam direction. These correlations provide a stringent test of perturbative QCD and show sensitivity to the contributions from different color configurations. Fixed-order perturbative calculations assuming the values of the color factors CF, CA, and TF as derived from a variety of gauge groups were compared to the measurements to study the underlying gauge group symmetry. The measured angular correlations in the deep inelastic ep scattering and photoproduction regimes are consistent with the admixture of color configurations as predicted by SU(3) and disfavour other symmetry groups, such as SU(N) in the limit of large N ; This work was supported by the U.S. Department of Energy, the Italian National Institute for Nuclear Physics (INFN), the German Federal Ministry for Education and Research (BMBF) under Contract No. H09PDF, No. 05h09GUF, and the SFB 676 of the Deutsche Forschungsgemeinschaft (DFG); DESY, Germany; the Science and Technology Facilities Council, United Kingdom; an FRGS grant from the Malaysian government; Presidential grant N-4142.2010.2 for Leading Scientific Schools, by the Russian Ministry of Education and Science through its grant for Scientific Research on High Energy Physics and under Contract No. 02.740.11.0244; the Netherlands Foundation for Research on Matter (FOM); the Israel Science Foundation; the Max Planck Institute for Physics, Munich, Germany; MEIN research grant No. 1 P03B 04529 (2005–2008), Poland; Warsaw University, Poland; the Russian Foundation for Basic Research, Grant 11-02- 91345-DFG_a; the Polish Ministry of Science and Higher Education as a scientific project No. DPN/N188/DESY/ 2009 and its grants for Scientific Research; the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT) and its grants for Scientific Research; the Korean Ministry of Education and Korea Science and Engineering Foundation; FNRS and its associated funds (IISN and FRIA) and by an Inter-University Attraction Poles Programme subsidized by the Belgian Federal Science Policy Office; the Spanish Ministry of Education and Science through funds provided by CICYT; the Natural Sciences and Engineering Research Council of Canada (NSERC); and the U.S. National Science Foundation

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAM ; A search for first-generation leptoquarks was performed in electron-proton and positron-proton collisions recorded with the ZEUS detector at HERA in 2003–2007 using an integrated luminosity of 366 pb-1. Final states with an electron and jets or with missing transverse momentum and jets were analyzed, searching for resonances or other deviations from the standard model predictions. No evidence for any leptoquark signal was found. The data were combined with data previously taken at HERA, resulting in a total integrated luminosity of 498 pb-1. Limits on the Yukawa coupling, λ, of leptoquarks were set as a function of the leptoquark mass for different leptoquark types within the Buchmüller-Rückl-Wyler model. Leptoquarks with a coupling λ = 0.3 are excluded for masses up to 699 GeV ; This work was supported by the U.S. Department of Energy; the Italian National Institute for Nuclear Physics (INFN); the German Federal Ministry for Education and Research (BMBF), under Contract No. 05 H09PDF; the Science and Technology Facilities Council, UK; an FRGS grant from the Malaysian government; the U.S. National Science Foundation (any opinion, findings and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation); the Polish Ministry of Science and Higher Education as a scientific project No. DPN/N188/DESY/2009; the Polish Ministry of Science and Higher Education and its grants for Scientific Research; the German Federal Ministry for Education and Research (BMBF), under Contract No. 05h09GUF, and the SFB 676 of the Deutsche Forschungsgemeinschaft (DFG); the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT) and its grants for Scientific Research; the Korean Ministry of Education and Korea Science and Engineering Foundation; FNRS and its associated funds (IISN and FRIA) and by an Inter- University Attraction Poles Programme subsidised by the Belgian Federal Science Policy Office; the Spanish Ministry of Education and Science through funds provided by CICYT; the Natural Sciences and Engineering Research Council of Canada (NSERC); supported by the German Federal Ministry for Education and Research (BMBF); R. F. Presidential Grant No. 4142.2010.2 for Leading Scientific Schools, by the Russian Ministry of Education and Science through its grant for Scientific Research on High Energy Physics and under Contract No. 02.740.11.0244; the Netherlands Foundation for Research on Matter (FOM); and the Israel Science Foundation. R. Aggarwal, P. Kaur, and I. Singh were supported by the Max Planck Institute for Physics, Munich, Germany. V. Aushev, Y. Aushev, V. Bokhonov, and N. Zhmak were supported by DESY, Hamburg, Germany. A. Kotanski was supported by the research Grant No. 1 P03B 04529 (2005-2008). W. Słomin´ski was supported by the Polish National Science Centre, Project No. DEC-2011/01/BST2/03643. J. Tomaszewska was partially supported by Warsaw University, Poland. K. Gladilin and I. A. Korzhavina were supported by the Russian Foundation for Basic Research, Grant No. 11-02-91345-DFG_a

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAM ; Measurements of neutral current cross sections for deep inelastic scattering in e+p collisions at HERA with a longitudinally polarized positron beam are presented. The single-differential cross-sections dσ/dQ2, dσ/dx and dσ/dy and the reduced cross section σ are measured in the kinematic region Q2>185 GeV2 and y<0.9, where Q2 is the four-momentum transfer squared, x the Bjorken scaling variable and y the inelasticity of the interaction. The measurements are performed separately for positively and negatively polarized positron beams. The measurements are based on an integrated luminosity of 135.5 pb-1 collected with the ZEUS detector in 2006 and 2007 at a center-of-mass energy of 318 GeV. The structure functions F3 and F3γZ are determined by combining the e+p results presented in this paper with previously published e-p neutral current results. The asymmetry parameter A+ is used to demonstrate the parity violation predicted in electroweak interactions. The measurements are well described by the predictions of the Standard Model ; Support was provided by the following: U.S. Department of Energy; Italian National Institute for Nuclear Physics (INFN); German Federal Ministry for Education and Research (BMBF) under Contract No. 05 H09PDF; the Science and Technology Facilities Council, UK; a F. R. S. grant from the Malaysian government; the U.S. National Science Foundation (any opinions, findings and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation); the Polish Ministry of Science and Higher Education as a scientific Project No. DPN/N188/DESY/2009; the Polish Ministry of Science and Higher Education and its grants for scientific research; the German Federal Ministry for Education and Research (BMBF) under Contract No. 05h09GUF, and the SFB 676 of the Deutsche Forschungsgemeinschaft (DFG); the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT) and its grants for scientific research; the Korean Ministry of Education and Korea Science and Engineering Foundation; the FNRS and its associated funds (IISN and FRIA) and by an Inter-University Attraction Poles Programme subsidized by the Belgian Federal Science Policy Office; the Spanish Ministry of Education and Science through funds provided by CICYT; the Natural Sciences and Engineering Research Council of Canada (NSERC); the German Federal Ministry for Education and Research (BMBF); R. F. Presidential Grant No. N 4142.2010.2 for Leading Scientific Schools, by the Russian Ministry of Education and Science through its grant for Scientific Research on High Energy Physics and under Contract No. 02.740.11.0244; the Netherlands Foundation for Research on Matter (FOM); the Israel Science Foundation, Max Planck Institute for Physics, Munich, Germany; the Polish National Science Centre, Project No. DEC-2011/01/BST2/03643; Warsaw University, Poland; DESY, Germany; and Russian Foundation for Basic Research, Grant No. 11-02-91345-DFG_a

A search is performed for WH production with a light Higgs boson decaying to hidden- sector particles resulting in clusters of collimated electrons, known as electron-jets. The search is performed with 2.04 fb−1 of data collected in 2011 with the ATLAS detector at the Large Hadron Collider in proton–proton collisions at √s = 7 TeV. One event satisfying the signal selection criteria is observed, which is consistent with the expected background rate. Limits on the product of the WH production cross section and the branching ratio of a Higgs boson decaying to prompt electron-jets are calculated as a function of a Higgs boson mass in the range from 100 to 140 GeV ; We acknowledge the support of ANPCyT, Argentina; YerPhI, Armenia; ARC, Australia; BMWF and FWF, Austria; ANAS, Azerbaijan; SSTC, Belarus; CNPq and FAPESP, Brazil; NSERC, NRC and CFI, Canada; CERN; CONICYT, Chile; CAS, MOST and NSFC, China; COLCIENCIAS, Colombia; MSMT CR, MPO CR and VSC CR, Czech Republic; DNRF, DNSRC and Lundbeck Foundation, Denmark; EPLANET, ERC and NSRF, European Union; IN2P3-CNRS, CEA-DSM/IRFU, France; GNSF, Georgia; BMBF, DFG, HGF, MPG and AvH Foundation, Germany; GSRT and NSRF, Greece; ISF, MINERVA, GIF, DIP and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; FOM and NWO, Netherlands; BRF and RCN, Norway; MNiSW, Poland; GRICES and FCT, Portugal; MERYS (MECTS), Romania; MES of Russia and ROSATOM, Russian Federation; JINR; MSTD, Serbia; MSSR, Slovakia; ARRS and MVZT, Slovenia; DST/NRF, South Africa; MICINN, Spain; SRC and Wallenberg Foundation, Sweden; SER, SNSF and Cantons of Bern and Geneva, Switzerland; NSC, Taiwan; TAEK, Turkey; STFC, the Royal Society and Leverhulme Trust, UK; DOE and NSF, USA. The crucial computing support from all WLCG partners is acknowledged gratefully, in particular from CERN and the ATLAS Tier-1 facilities at TRIUMF (Canada), NDGF (Denmark, Norway, Sweden), CC-IN2P3 (France), KIT/GridKA (Germany), INFNCNAF (Italy), NL-T1 (Netherlands), PIC (Spain), ASGC (Taiwan), RAL (UK) and BNL (USA) and in the Tier-2 facilities worldwide

The ATLAS detector at the Large Hadron Collider is used to search for excited electrons and excited muons in the channel pp → ℓℓ* → ℓℓγ, assuming that excited leptons are produced via contact interactions. The analysis is based on 13 fb-1 of pp collisions at a centre-of-mass energy of 8 TeV. No evidence for excited leptons is found, and a limit is set at the 95% credibility level on the cross section times branching ratio as a function of the excited-lepton mass mℓ*. For mℓ*> 0.8 TeV, the respective upper limits on σB(ℓ* → ℓγ) are 0.75 and 0.90 fb for the e* and μ* searches. Limits on σB are converted into lower bounds on the compositeness scale Λ. In the special case where Λ = m ℓ*, excited-electron and excited-muon masses below 2.2 TeV are excluded ; We acknowledge the support of ANPCyT, Argentina; YerPhI, Armenia; ARC, Australia; BMWF and FWF, Austria; ANAS, Azerbaijan; SSTC, Belarus; CNPq and FAPESP, Brazil; NSERC, NRC and CFI, Canada; CERN; CONICYT, Chile; CAS, MOST and NSFC, China; COLCIENCIAS, Colombia; MSMT CR, MPO CR and VSC CR, Czech Republic; DNRF, DNSRC and Lundbeck Foundation, Denmark; EPLANET, ERC and NSRF, European Union; IN2P3-CNRS, CEA-DSM/IRFU, France; GNSF, Georgia; BMBF, DFG, HGF, MPG and AvH Foundation, Germany; GSRT and NSRF, Greece; ISF, MINERVA, GIF, DIP and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; FOM and NWO, Netherlands; BRF and RCN, Norway; MNiSW, Poland; GRICES and FCT, Portugal; MERYS (MECTS), Romania; MES of Russia and ROSATOM, Russian Federation; JINR; MSTD, Serbia; MSSR, Slovakia; ARRS and MIZˇ S, Slovenia; DST/NRF, South Africa; MICINN, Spain; SRC and Wallenberg Foundation, Sweden; SER, SNSF and Cantons of Bern and Geneva, Switzerland; NSC, Taiwan; TAEK, Turkey; STFC, the Royal Society and Leverhulme Trust, UK; DOEand NSF, USA. The crucial computing support from all WLCG partners is acknowledged gratefully, in particular from CERN and the ATLAS Tier-1 facilities at TRIUMF (Canada), NDGF (Denmark, Norway, Sweden), CC-IN2P3 (France), KIT/GridKA (Germany), INFNCNAF (Italy), NL-T1 (Netherlands), PIC (Spain), ASGC (Taiwan), RAL (UK) and BNL (USA) and in the Tier-2 facilities worldwide

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