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  • 2014-12-02Master thesis Open access Show more
  • A measurement of the ratio of the production cross sections for $W$ and $Z$ bosons in association with jets with the ATLAS detector
    Publication . ATLAS collaboration (2896 authors); Aguilar-Saavedra, Juan Antonio; Amor Dos Santos, Susana Patricia; Anjos, Nuno; Araque, Juan Pedro; Cantrill, Robert; Carvalho, João; Castro, Nuno Filipe; Conde Muiño, Patricia; Da Cunha Sargedas De Sousa, Mario Jose; Do Valle Wemans, André; Fiolhais, Miguel; Galhardo, Bruno; Gomes, Agostinho; Gonçalo, Ricardo; Jorge, Pedro; Lopes, Lourenco; Machado Miguens, Joana; Maio, Amélia; Maneira, José; Marques, Carlos; Onofre, António; Palma, Alberto; Pedro, Rute; Pina, João Antonio; Pinto, Belmiro; Santos, Helena; Saraiva, João; Silva, José; Tavares Delgado, Ademar; Veloso, Filipe; Wolters, Helmut
    The ratio of the production cross sections for $W$ and $Z$ bosons in association with jets has been measured in proton–proton collisions at $\sqrt{s}=7\,\mathrm {TeV}$ with the ATLAS experiment at the Large Hadron Collider. The measurement is based on the entire 2011 dataset, corresponding to an integrated luminosity of $4.6\,\mathrm {fb}^{-1}$ . Inclusive and differential cross-section ratios for massive vector bosons decaying to electrons and muons are measured in association with jets with transverse momentum $p_\mathrm {T} >30\,\mathrm {GeV}$ and jet rapidity $|y| < 4.4$ . The measurements are compared to next-to-leading-order perturbative QCD calculations and to predictions from different Monte Carlo generators implementing leading-order matrix elements supplemented by parton showers.
    2014-12-02Journal article Open access Show more
  • Identification techniques for highly boosted W bosons that decay into hadrons
    Publication . CMS collaboration (2145 authors); Hollar, Jonathan; Nayak, Aruna; Bargassa, Pedrame; Beirão Da Cruz E Silva, Cristóvão; Faccioli, Pietro; Ferreira Parracho, Pedro Guilherme; Gallinaro, Michele; Nguyen, Federico; Rodrigues Antunes, Joao; Seixas, Joao; Varela, Joao; Vischia, Pietro; Lloret Iglesias, Lara; David Tinoco Mendes, Andre; Musella, Pasquale; Silva, Pedro; Pela, Joao; Leonardo, Nuno
    In searches for new physics in the energy regime of the LHC, it is becoming increasingly important to distinguish single-jet objects that originate from the merging of the decay products of W bosons produced with high transverse momenta from jets initiated by single partons. Algorithms are defined to identify such W jets for different signals of interest, using techniques that are also applicable to other decays of bosons to hadrons that result in a single jet, such as those from highly boosted Z and Higgs bosons. The efficiency for tagging W jets is measured in data collected with the CMS detector at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.7 fb$^{−1}$. The performance of W tagging in data is compared with predictions from several Monte Carlo simulators.
    2014-12-02Journal article Open access Show more