
ATLAS Collaboration(Aad, G. et al), Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Fassi, F., Ferrer, A., et al. (2014). Search for highmass dilepton resonances in pp collisions at root s = 8 TeV with the ATLAS detector. Phys. Rev. D, 90(5), 052005–30pp.
Abstract: The ATLAS detector at the Large Hadron Collider is used to search for highmass resonances decaying to dielectron or dimuon final states. Results are presented from an analysis of protonproton (pp) collisions at a centerofmass energy of 8 TeV corresponding to an integrated luminosity of 20.3 fb(1) in the dimuon channel. A narrow resonance with Standard Model Z couplings to fermions is excluded at 95% confidence level for masses less than 2.79 TeV in the dielectron channel, 2.53 TeV in the dimuon channel, and 2.90 TeV in the two channels combined. Limits on other model interpretations are also presented, including a grandunification model based on the E6 gauge group, Z* bosons, minimal Z' models, a spin2 graviton excitation from RandallSundrum models, quantum black holes, and a minimal walking technicolor model with a composite Higgs boson.



Campanario, F., Kerner, M., Ninh, D. L., & Zeppenfeld, D. (2014). Nexttoleading order QCD corrections to ZZ production in association with two jets. J. High Energy Phys., 07(7), 148–14pp.
Abstract: We present a calculation of nexttoleading order QCD corrections to QCDinduced ZZ production in association with two jets at hadron colliders. Both Z bosons decay leptonically with all offshell effects, virtual photon contributions and spincorrelation effects fully taken into account. This process is an important background to weak boson scattering and to searches for signals of new physics beyond the Standard Model. As expected, the nexttoleading order corrections reduce significantly the scale uncertainty and show a nontrivial phase space dependence in kinematic distributions. Our code will be publicly available as part of the parton level Monte Carlo program VBFNLO.



ATLAS Collaboration(Aad, G. et al), Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Fassi, F., Ferrer, A., et al. (2014). Measurement of the centrality and pseudorapidity dependence of the integrated elliptic flow in leadlead collisions at root SNN=2.76 TeV with the ATLAS detector. Eur. Phys. J. C, 74(8), 2982–25pp.
Abstract: The integrated elliptic flow of charged particles produced in Pb+Pb collisions at root SNN = 2.76 TeV has been measured with the ATLAS detector using data collected at the Large Hadron Collider. The anisotropy parameter, upsilon(2), was measured in the pseudorapidity range eta <= 2.5 with the eventplane method. In order to include tracks with very low transverse momentum p(T), thus reducing the uncertainty in upsilon(2) integrated over p(T), a 1 μb(1) data sample recorded without a magnetic field in the tracking detectors is used. The centrality dependence of the integrated upsilon(2) is compared to other measurements obtained with higher PT thresholds. The integrated elliptic flow is weakly decreasing with eta. The integrated upsilon 2 transformed to the rest frame of one of the colliding nuclei is compared to the lowerenergy RHIC data.



ATLAS Collaboration(Aad, G. et al), Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Fassi, F., Ferrer, A., et al. (2014). Monitoring and data quality assessment of the ATLAS liquid argon calorimeter. J. Instrum., 9, P07024–55pp.
Abstract: The liquid argon calorimeter is a key component of the ATLAS detector installed at the CERN Large Hadron Collider. The primary purpose of this calorimeter is the measurement of electron and photon kinematic properties. It also provides a crucial input for measuring jets and missing transverse momentum. An advanced data monitoring procedure was designed to quickly identify issues that would affect detector performance and ensure that only the best quality data are used for physics analysis. This article presents the validation procedure developed during the 2011 and 2012 LHC datataking periods, in which more than 98% of the protonproton luminosity recorded by ATLAS at a centreofmass energy of 78 TeV had calorimeter data quality suitable for physics analysis.



Aguilar, A. C., Binosi, D., Ibañez, D., & Papavassiliou, J. (2014). New method for determining the quarkgluon vertex. Phys. Rev. D, 90(6), 065027–26pp.
Abstract: We present a novel nonperturbative approach for calculating the form factors of the quarkgluon vertex in terms of an unknown threepoint function, in the Landau gauge. The key ingredient of this method is the exact allorder relation connecting the conventional quarkgluon vertex with the corresponding vertex of the background field method, which is Abelianlike. When this latter relation is combined with the standard gauge technique, supplemented by a crucial set of transverse Ward identities, it allows the approximate determination of the nonperturbative behavior of all 12 form factors comprising the quarkgluon vertex, for arbitrary values of the momenta. The actual implementation of this procedure is carried out in the Landau gauge, in order to make contact with the results of lattice simulations performed in this particular gauge. The most demanding technical aspect involves the approximate calculation of the components of the aforementioned (fully dressed) threepoint function, using lattice data as input for the gluon propagators appearing in its diagrammatic expansion. The numerical evaluation of the relevant form factors in three special kinematical configurations (softgluon and quark symmetric limit, zero quark momentum) is carried out in detail, finding qualitative agreement with the available lattice data. Most notably, a concrete mechanism is proposed for explaining the puzzling divergence of one of these form factors observed in lattice simulations.



Kersten, J., Park, J. H., Stockinger, D., & VelascoSevilla, L. (2014). Understanding the correlation between (g2)(mu) and μ> e gamma in the MSSM. J. High Energy Phys., 08(8), 118–32pp.
Abstract: The supersymmetric contributions to the muon anomalous magnetic moment a and to the decay μ> e gamma are given by very similar Feynman diagrams. Previous works reported correlations in specific scenarios, in particular if alpha(mu) is dominated by a single diagram. In this work we give an extensive survey of the possible correlations. We discuss examples of singlediagram domination with particularly strong correlations, and provide corresponding benchmark parameter points. We show how the correlations are weakened by significant cancellations between diagrams in large parts of the MSSM parameter space. Nevertheless, the order of magnitude of BR(mu > e gamma) for a fixed flavorviolating parameter can often be predicted. We summarize the behavior by plotting the correlations as well as resulting bounds on the flavorviolating parameters under various assumptions on the MSSM spectrum.



LHCb Collaboration(Aaij, R. et al), MartinezVidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2014). Measurement of CP asymmetry in D0 > K K+ and D0 > pi() pi(+) decays. J. High Energy Phys., 07(7), 041–25pp.
Abstract: Timeintegrated CP asymmetries in D0 decays to the final states K K+ and pi() pi(+) are measured using protonproton collisions corresponding to 3 fb(1) of integrated luminosity collected at centreofmass energies of 7 TeV and 8 TeV. The D0 mesons are produced in semileptonic bhadron decays, where the charge of the accompanying muon is used to determine the initial flavour of the charm meson. The difference in CP asymmetries between the two final states is measured to be Delta A(CP) = A(CP)(K K+) – A(CP)(pi() pi(+)) = (+0.14 +/ 0.16 (stat) +/ 0.08 (syst))% . A measurement of A(CP)(K K+) is obtained assuming negligible CP violation in charm mixing and in Cabibbofavoured D decays. It is found to be A(CP)(K K+) = (0.06 +/ 0.15 (stat) +/ 0.10 (syst))% , where the correlation coefficient between Delta A(CP) and A(CP)(K K+) is rho = 0.28. By combining these results, the CP asymmetry in the D0 > pi() pi(+) channel is A(CP)(pi() pi(+)) = (0.20 +/ 0.19 (stat) +/ 0.10 (syst))%.



Boucenna, M. S., Morisi, S., & Valle, J. W. F. (2014). Radiative neutrino mass in 331 scheme. Phys. Rev. D, 90(1), 013005–5pp.
Abstract: We propose a new radiative mechanism for neutrino mass generation based on the SU(3)(c) circle times SU(3)(L) circle times U(1)(X) electroweak gauge group. Lepton number is a symmetry of the Yukawa sector which is spontaneously broken in the gauge sector. As a result light Majorana masses arise from neutral gauge boson exchanges at the oneloop level. In addition to the isosinglet neutrinos that may be produced at the LHC through the extended gauge boson portals, the model contains new quarks which can also lie at the TeV scale, and which can provide a plethora of accessible collider phenomena.



Di Valentino, E., Giusarma, E., Lattanzi, M., Melchiorri, A., & Mena, O. (2014). Axion cold dark matter: Status after Planck and BICEP2. Phys. Rev. D, 90(4), 043534–11pp.
Abstract: We investigate the axion dark matter scenario (ADM), in which axions account for all of the dark matter in the Universe, in light of the most recent cosmological data. In particular, we use the Planck temperature data, complemented by WMAP Epolarization measurements, as well as the recent BICEP2 observations of Bmodes. Baryon acoustic oscillation data, including those from the baryon oscillation spectroscopic survey, are also considered in the numerical analyses. We find that, in the minimal ADM scenario and for Delta(QCD) = 200 MeV, the full data set implies that the axion mass m(a) = 82.2 +/ 1.1 μeV [corresponding to the PecceiQuinn symmetry being broken at a scale f(a) = (7.54 +/ 0.10) x 10(10) GeV], or m(a) = 76.6 +/ 2.6 μeV [f(a) = (8.08 +/ 0.27) x 10(10) GeV] when we allow for a nonstandard effective number of relativistic species Neff. We also find a 2 sigma preference for Neff > 3.046. The limit on the sum of neutrino masses is Sigma m(v) < 0.25 eV at 95% C.L. for Neff = 3.046, or Sigma m(v) < 0.47 eV when Neff is a free parameter. Considering extended scenarios where either the dark energy equationofstate parameter w, the tensor spectral index n(t), or the running of the scalar index dn(s)/d ln k is allowed to vary does not change significantly the axion massenergy density constraints. However, in the case of the full data set exploited here, there is a preference for a nonzero tensor index or scalar running, driven by the different tensor amplitudes implied by the Planck and BICEP2 observations. We also study the effect on our estimates of theoretical uncertainties, in particular the imprecise knowledge of the QCD scale Delta(QCD), in the calculation of the temperaturedependent axion mass. We find that in the simplest ADM scenario the Planck + WP data set implies that the axion mass m(a) = 63.7 +/ 1.2 μeV for Delta(QCD) = 400 MeV. We also comment on the possibility that axions do not make up for all the dark matter, or that the contribution of stringproduced axions has been grossly underestimated; in that case, the values that we find for the mass can conservatively be considered as lower limits. Dark matter axions with mass in the 6080 μeV (corresponding to an axionphoton coupling G(a gamma gamma) similar to 10(14) GeV1) range can, in principle, be detected by looking for axiontophoton conversion occurring inside a tunable microwave cavity permeated by a highintensity magnetic field, and operating at a frequency nu similar or equal to 1520 GHz. This is out of the reach of current experiments like the axion dark matter experiment (limited to a maximum frequency of a few GHzs), but is, on the other hand, within the reach of the upcoming axion dark matter experimenthigh frequency experiment that will explore the 440 GHz frequency range and then be sensitive to axion masses up to similar to 160 μeV.



Strege, C., Bertone, G., Besjes, G. J., Caron, S., Ruiz de Austri, R., Strubig, A., et al. (2014). Profile likelihood maps of a 15dimensional MSSM. J. High Energy Phys., 09(9), 081–59pp.
Abstract: We present statistically convergent profile likelihood maps obtained via global fits of a phenomenological Minimal Supersymmetric Standard Model with 15 free parameters (the MSSM15), based on over 250M points. We derive constraints on the model parameters from direct detection limits on dark matter, the Planck relic density measurement and data from accelerator searches. We provide a detailed analysis of the rich phenomenology of this model, and determine the SUSY mass spectrum and dark matter properties that are preferred by current experimental constraints. We evaluate the impact of the measurement of the anomalous magnetic moment of the muon (g – 2) on our results, and provide an analysis of scenarios in which the lightest neutralino is a subdominant component of the dark matter. The MSSM15 parameters are relatively weakly constrained by current data sets, with the exception of the parameters related to dark matter phenomenology (M1, M2, mu), which are restricted to the subTeV regime, mainly due to the relic density constraint. The mass of the lightest neutralino is found to be < 1.5TeV at 99% C.L., but can extend up to 3 TeV when excluding the g – 2 constraint from the analysis. Lowmass binolike neutralinos are strongly favoured, with spinindependent scattering crosssections extending to very small values, similar to 10(20) pb. ATLAS SUSY null searches strongly impact on this mass range, and thus rule out a region of parameter space that is outside the reach of any current or future direct detection experiment. The bestfit point obtained after inclusion of all data corresponds to a squark mass of 2.3 TeV, a gluino mass of 2.1 TeV and a 130 GeV neutralino with a spinindependent crosssection of 2.4 x 10(10) pb, which is within the reach of future multiton scale direct detection experiments and of the upcoming LHC run at increased centreofmass energy.

