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A Longitudinal Investigation Of Business Angel Relationship Risk Mitigation Strategies Within Investments - A Three-dimensional Approach
- 2015
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Proceedings (redaktörskap) (refereegranskat)abstract
- Business angel (BA) investing is associated with various types of risks, where relationship risk often is highlighted as being especially critical (Fiet, 1995). Three investor strategies for mitigating relationship risks associated with BA investing in young private firms can be traced in the literature: (i) indirect control through monitoring and rewarding/punishing entrepreneur behavior and output, (ii) direct control through active involvement, and (iii) relying on mutual trust (Van Osnabrugge and Robinson, 2000; Maxwell and Lévesque, 2011). While early research in the field adopted a rather static view on BA categorization (Coveney and Moore, 1998; Sørheim and Landström, 2001), more contemporary research shows that BAs change investment roles across investments (Avdeitchikova, 2008; Lahti, 2011). However, whether BAs behave differently regarding risk mitigation within investments is less explored. This explorative study contributes to the opening of the black box of how BAs may shift risk mitigation strategies over time within single investments.
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| 5. |
- Aaboud, M., et al.
(författare)
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Direct top-quark decay width measurement in the t(t)over-bar lepton plus jets channel at root s=8 TeV with the ATLAS experiment
- 2018
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 78
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a direct measurement of the decay width of the top quark using t (t) over bar events in the lepton+jets final state. The data sample was collected by the ATLAS detector at the LHC in proton-proton collisions at a centre-of-mass energy of 8 TeV and corresponds to an integrated luminosity of 20.2 fb(-1). The decay width of the top quark is measured using a template fit to distributions of kinematic observables associated with the hadronically and semileptonically decaying top quarks. The result, Gamma(t) = 1.76 +/- 0.33 (stat.) (+0.79)(-0.68) (syst.) GeV for a top-quark mass of 172.5 GeV, is consistent with the prediction of the Standard Model.
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| 6. |
- Aaboud, M, et al.
(författare)
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Measurement of jet pT correlations in Pb + Pb and pp collisions at sNN=2.76 TeVwith the ATLAS detector
- 2017
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 774, s. 379-402
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Tidskriftsartikel (refereegranskat)abstract
- Measurements of dijet pT correlations in Pb+Pb and pp collisions at a nucleon–nucleon centre-of-mass energy of sNN=2.76 TeV are presented. The measurements are performed with the ATLAS detector at the Large Hadron Collider using Pb+Pb and pp data samples corresponding to integrated luminosities of 0.14 nb−1 and 4.0 pb−1, respectively. Jets are reconstructed using the anti-kt algorithm with radius parameter values R=0.3 and R=0.4. A background subtraction procedure is applied to correct the jets for the large underlying event present in Pb+Pb collisions. The leading and sub-leading jet transverse momenta are denoted pT1 and pT2. An unfolding procedure is applied to the two-dimensional (pT1,pT2) distributions to account for experimental effects in the measurement of both jets. Distributions of (1/N)dN/dxJ, where xJ=pT2/pT1, are presented as a function of pT1 and collision centrality. The distributions are found to be similar in peripheral Pb+Pb collisions and pp collisions, but highly modified in central Pb+Pb collisions. Similar features are present in both the R=0.3 and R=0.4 results, indicating that the effects of the underlying event are properly accounted for in the measurement. The results are qualitatively consistent with expectations from partonic energy loss models. © 2017 The Author
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| 7. |
- Aaboud, M, et al.
(författare)
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Measurement of lepton differential distributions and the top quark mass in tt¯ production in pp collisions at √s=8 TeV with the ATLAS detector
- 2017
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 77:11
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents single lepton and dilepton kinematic distributions measured in dileptonic tt¯ events produced in 20.2fb - 1 of s=8 TeV pp collisions recorded by the ATLAS experiment at the LHC. Both absolute and normalised differential cross-sections are measured, using events with an opposite-charge eμ pair and one or two b-tagged jets. The cross-sections are measured in a fiducial region corresponding to the detector acceptance for leptons, and are compared to the predictions from a variety of Monte Carlo event generators, as well as fixed-order QCD calculations, exploring the sensitivity of the cross-sections to the gluon parton distribution function. Some of the distributions are also sensitive to the top quark pole mass; a combined fit of NLO fixed-order predictions to all the measured distributions yields a top quark mass value of mtpole=173.2±0.9±0.8±1.2 GeV, where the three uncertainties arise from data statistics, experimental systematics, and theoretical sources. © 2017, CERN for the benefit of the ATLAS collaboration.
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| 8. |
- Aaboud, M, et al.
(författare)
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Measurement of the azimuthal anisotropy of charged particles produced in √sNN = 5.02 TeV Pb+Pb collisions with the ATLAS detector
- 2018
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 78:12
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Tidskriftsartikel (refereegranskat)abstract
- Measurements of the azimuthal anisotropy in lead–lead collisions at sNN = 5.02 TeV are presented using a data sample corresponding to 0.49 nb - 1 integrated luminosity collected by the ATLAS experiment at the LHC in 2015. The recorded minimum-bias sample is enhanced by triggers for “ultra-central” collisions, providing an opportunity to perform detailed study of flow harmonics in the regime where the initial state is dominated by fluctuations. The anisotropy of the charged-particle azimuthal angle distributions is characterized by the Fourier coefficients, v2–v7, which are measured using the two-particle correlation, scalar-product and event-plane methods. The goal of the paper is to provide measurements of the differential as well as integrated flow harmonics vn over wide ranges of the transverse momentum, 0.5 < pT< 60 GeV, the pseudorapidity, | η| < 2.5, and the collision centrality 0–80%. Results from different methods are compared and discussed in the context of previous and recent measurements in Pb+Pb collisions at sNN = 2.76 TeV and 5.02 TeV. In particular, the shape of the pTdependence of elliptic or triangular flow harmonics is observed to be very similar at different centralities after scaling the vn and pTvalues by constant factors over the centrality interval 0–60% and the pTrange 0.5 < pT< 5 GeV. © 2018, CERN for the benefit of the ATLAS collaboration.
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| 9. |
- Aaboud, M., et al.
(författare)
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Measurements of b-jet tagging efficiency with the ATLAS detector using tt¯" role="presentation">tt¯ events at s=13" role="presentation">s√=13 TeV
- 2018
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Ingår i: Journal of High Energy Physics (JHEP). - : SPRINGER. - 1126-6708 .- 1029-8479. ; :8
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Tidskriftsartikel (refereegranskat)abstract
- The efficiency to identify jets containing b-hadrons (b-jets) is measured using a high purity sample of dileptonic top quark-antiquark pairs (t (t) over bar) selected from the 36.1 fb(-1) of data collected by the ATLAS detector in 2015 and 2016 from proton-proton collisions produced by the Large Hadron Collider at a centre-of-mass energy root s = 13 TeV. Two methods are used to extract the efficiency from t (t) over bar events, a combinatorial likelihood approach and a tag-and-probe method. A boosted decision tree, not using b-tagging information, is used to select events in which two b-jets are present, which reduces the dominant uncertainty in the modelling of the flavour of the jets. The efficiency is extracted for jets in a transverse momentum range from 20 to 300 GeV, with data-to-simulation scale factors calculated by comparing the efficiency measured using collision data to that predicted by the simulation. The two methods give compatible results, and achieve a similar level of precision, measuring data-to-simulation scale factors close to unity with uncertainties ranging from 2% to 12% depending on the jet transverse momentum.
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| 10. |
- Aaboud, M, et al.
(författare)
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Measurements of top-quark pair differential cross-sections in the lepton+jets channel in pp collisions at √s=13 TeV using the ATLAS detector
- 2017
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Ingår i: Journal of High Energy Physics. - 1029-8479 .- 1126-6708. ; 2017:11
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Tidskriftsartikel (refereegranskat)abstract
- Measurements of differential cross-sections of top-quark pair production in fiducial phase-spaces are presented as a function of top-quark and tt¯ system kinematic observables in proton-proton collisions at a centre-of-mass energy of s=13 TeV. The data set corresponds to an integrated luminosity of 3.2 fb−1, recorded in 2015 with the ATLAS detector at the CERN Large Hadron Collider. Events with exactly one electron or muon and at least two jets in the final state are used for the measurement. Two separate selections are applied that each focus on different top-quark momentum regions, referred to as resolved and boosted topologies of the tt¯ final state. The measured spectra are corrected for detector effects and are compared to several Monte Carlo simulations by means of calculated χ2 and p-values. © 2017, The Author(s).
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