Physics objects for top quark physics in ATLAS

Top quark physics measurements performed using data from the ATLAS detector at the LHC rely on efficient reconstruction and precise calibration of leptons, jets and missing transverse energy. A review of the techniques used to reconstruct such objects is given, with an emphasis on the uncertainties achieved for energy calibration and efficiency measurements, illustrated with their impact on key top quark physics results.Comment: 5 pages, 3 figures, proceedings of Top2016 conferenc

Inclusive ttˉt\bar{t} cross-section measurements at LHC

A review of ATLAS and CMS measurements of the inclusive $t\bar{t}$ production cross-section in $pp$ collisions at $\sqrt{s}=$7-13 TeV is presented, focusing on the most precise results in the dilepton and lepton+jets final states. The measurements are in good agreement with state-of-the-art QCD predictions, and have been used to determine the top quark pole mass and provide constraints on proton parton distribution functions.Comment: 5 pages, 3 figures, proceedings of the Top2017 conferenc

Electroweak and CP violation physics at a Linear Collider Z-factory

A future linear collider such as TESLA may be able to run on the Z0 resonance with very high luminosity and polarised electron and positron beams. The possibilities of measuring electroweak quantities with high precision are investigated. Huge improvements with respect to the present precision can be expected, especially for the asymmetries A_LR and A_b where beam polarisation can be exploited. The very large sample of Z to bbbar events also allows studies of various CP-violating b decays. The precision achievable on the CKM unitarity triangle angles is comparable to experiments at b factories and future hadron colliders.Comment: 26 pages, 11 figures. To be submitted to European Journal of Physics Direc

Top quark property measurements at the LHC

Measurements of top quark properties performed at the Large Hadron Collider are reviewed, with a particular emphasis on top-pair charge asymmetries, spin correlations and polarization measurements performed by the ATLAS and CMS collaborations. The measurements are generally in good agreement with predictions from next-to-leading-order QCD calculations, and no deviations from Standard Model expectations have been seen.Comment: 5 pages, 4 figures, to appear in proceedings of Top 2014, Cannes, France, 28th Sept - 3rd Oct 201

Study of e/gamma trigger for the electron calibration stream

This note describes a study of the possibilities for selecting an electron calibration stream using the High level electron trigger (Level 2 and the event filter). Using the electromagnetic calorimeter reconstruction and the track reconstruction algorithms, an evaluation has been performed of the selection efficiencies and purities for different physics channels with single or double electrons in the final state. A study of the calibration stream composition, including the background from QCD processes, is presented.Comment: 14 page

B Physics at the Z0 Resonance

B physics results from e+ e- annihilation at the Z0 resonance are reviewed. A vast program is summarised, including the study of B+, B0d, B0s and b baryon lifetimes, the time dependence of B0d and B0s oscillations, the width difference in the B0s system, and the measurements of the magnitudes of the CKM matrix elements Vcb and Vub.Comment: 17 pages, 8 figures, presented at the UK Phenomenology Workshop on Heavy Flavour and CP Violation, 17-22 September 200

The influence of glacial cover on riverine silicon and iron exports in Chilean Patagonia

Glaciated environments have been highlighted as important sources of bioavailable nutrients, with inputs of glacial meltwater potentially influencing productivity in downstream ecosystems. However, it is currently unclear how riverine nutrient concentrations vary across a spectrum of glacial cover, making it challenging to accurately predict how terrestrial fluxes will change with continued glacial retreat. Using 40 rivers in Chilean Patagonia as a unique natural laboratory, we investigate how glacial cover affects riverine Si and Fe concentrations, and infer how exports of these bioessential nutrients may change in the future. Dissolved Si (as silicic acid) and soluble Fe (0.45 mu m) phases of both Si and Fe, which are not typically accounted for in terrestrial nutrient budgets but can dominate riverine exports. Dissolved Si and soluble Fe yield estimates showed no trend with glacial cover, suggesting no significant change in total exports with continued glacial retreat. However, yields of colloidal-nanoparticulate and reactive sediment-bound Si and Fe were an order of magnitude greater in highly glaciated catchments and showed significant positive correlations with glacial cover. As such, regional-scale exports of these phases are likely to decrease as glacial cover disappears across Chilean Patagonia, with potential implications for downstream ecosystems

Bose-Einstein Correlations of Three Charged Pions in Hadronic Z^0 Decays

Bose-Einstein Correlations (BEC) of three identical charged pions were studied in 4 x 10^6 hadronic Z^0 decays recorded with the OPAL detector at LEP. The genuine three-pion correlations, corrected for the Coulomb effect, were separated from the known two-pion correlations by a new subtraction procedure. A significant genuine three-pion BEC enhancement near threshold was observed having an emitter source radius of r_3 = 0.580 +/- 0.004 (stat.) +/- 0.029 (syst.) fm and a strength of \lambda_3 = 0.504 +/- 0.010 (stat.) +/- 0.041 (syst.). The Coulomb correction was found to increase the \lambda_3 value by \~9% and to reduce r_3 by ~6%. The measured \lambda_3 corresponds to a value of 0.707 +/- 0.014 (stat.) +/- 0.078 (syst.) when one takes into account the three-pion sample purity. A relation between the two-pion and the three-pion source parameters is discussed.Comment: 19 pages, LaTeX, 5 eps figures included, accepted by Eur. Phys. J.

TESLA Technical Design Report Part III: Physics at an e+e- Linear Collider

The TESLA Technical Design Report Part III: Physics at an e+e- Linear ColliderComment: 192 pages, 131 figures. Some figures have reduced quality. Full quality figures can be obtained from http://tesla.desy.de/tdr. Editors - R.-D. Heuer, D.J. Miller, F. Richard, P.M. Zerwa