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Campanario, F., Kerner, M., Ninh, L. D., & Zeppenfeld, D. (2014). Z gamma production in association with two jets at next-to-leading order QCD. Eur. Phys. J. C, 74(9), 3085–7pp.
Abstract: Next-to-leading order QCD corrections to the QCD-induced pp -> l(+)l(-)gamma j j + X and pp -> <(nu)lover bar>(l)nu(l)gamma(jj) + X processes are presented. The latter is used to find an optimal cut to reduce the contribution of radiative photon emission off the charged leptons in the first channel. As expected, the scale uncertainties are significantly reduced at NLO and the QCD corrections are phase-space dependent and important for precise measurements at the LHC.
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FLAG Working Group(Aoki, S. et al), & Della Morte, M. (2014). Review of lattice results concerning low-energy particle physics. Eur. Phys. J. C, 74(9), 2890–179pp.
Abstract: We review lattice results related to pion, kaon, D- and B-meson physics with the aim of making them easily accessible to the particle-physics community. More specifically, we report on the determination of the light-quark masses, the form factor f(+)(0), arising in semileptonic K -> pi transition at zero momentum transfer, as well as the decay-constant ratio f(K)/f(pi) of decay constants and its consequences for the CKM matrix elements V-us and V-ud. Furthermore, we describe the results obtained on the lattice for some of the low-energy constants of SU(2)(L) x SU(2)(R) and SU(3)(L) x SU(3)(R) Chiral Perturbation Theory and review the determination of the B-K parameter of neutral kaon mixing. The inclusion of heavy-quark quantities significantly expands the FLAG scope with respect to the previous review. Therefore, we focus here on D- and B-meson decay constants, form factors, and mixing parameters, since these are most relevant for the determination of CKM matrix elements and the global CKM unitarity-triangle fit. In addition we review the status of lattice determinations of the strong coupling constant alpha(s).
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ATLAS Collaboration(Aad, G. et al), Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Ferrer, A., Fiorini, L., et al. (2014). Muon reconstruction efficiency and momentum resolution of the ATLAS experiment in proton-proton collisions at root s=7 TeV in 2010. Eur. Phys. J. C, 74(9), 3034–32pp.
Abstract: This paper presents a study of the performance of the muon reconstruction in the analysis of proton-proton collisions at root s = 7TeV at the LHC, recorded by the ATLAS detector in 2010. This performance is described in terms of reconstruction and isolation efficiencies and momentum resolutions for different classes of reconstructed muons. The results are obtained from an analysis of J/psi meson and Z boson decays to dimuons, reconstructed from a data sample corresponding to an integrated luminosity of 40 pb(-1). The measured performance is compared to Monte Carlo predictions and deviations from the predicted performance are discussed.
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Gonzalez Felipe, R., Ivanov, I. P., Nishi, C. C., Serodio, H., & Silva, J. P. (2014). Constraining multi-Higgs flavour models. Eur. Phys. J. C, 74(7), 2953–12pp.
Abstract: To study a flavour model with a non-minimal Higgs sector one must first define the symmetries of the fields; then identify what types of vacua exist and how they may break the symmetries; and finally determine whether the remnant symmetries are compatible with the experimental data. Here we address all these issues in the context of flavour models with any number of Higgs doublets. We stress the importance of analysing the Higgs vacuum expectation values that are pseudo-invariant under the generators of all subgroups. It is shown that the only way of obtaining a physical CKM mixing matrix and, simultaneously, non-degenerate and non-zero quark masses is requiring the vacuum expectation values of the Higgs fields to break completely the full flavour group, except possibly for some symmetry belonging to baryon number. The application of this technique to some illustrative examples, such as the flavour groups Delta (27), A(4) and S-3, is also presented.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2014). Measurement of the forward W boson cross-section in pp collisions at root s = 7 TeV. J. High Energy Phys., 12(12), 079–25pp.
Abstract: A measurement of the inclusive W -> μnu production cross-section using data from pp collisions at a centre-of-mass energy of root s=7 TeV is presented. The analysis is based on an integrated luminosity of about 1.0 fb(-1) recorded with the LHCb detector. Results are reported for muons with a transverse momentum greater than 20 GeV/c and pseudorapidity between 2.0 and 4.5. The W+ and W- production cross-sections are measured to be sigma(W+->mu+nu)=861.0 +/- 2.0 +/- 11.2 +/- 14.7pb, sigma(W-->mu-(nu)over bar)=675.8 +/- 1.9 +/- 8.8 +/- 11.6pb, where the first uncertainty is statistical, the second is systematic and the third is due to the luminosity determination. Cross-section ratios and differential distributions as functions of the muon pseudorapidity are also presented. The ratio of W+ to W- cross-sections in the same fiducial kinematic region is determined to be sigma(W+->mu+nu)/sigma(W-->mu-(nu)over bar) = 1.274 +/- 0.005 +/- 0.009, where the uncertainties are statistical and systematic, respectively. Results are in good agreement with theoretical predictions at next-to-next-to-leading order in perturbative quantum chromodynamics.
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