| 1. |
- Abdulov, N. A., et al.
(författare)
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TMDlib2 and TMDplotter : a platform for 3D hadron structure studies
- 2021
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 81:8
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Tidskriftsartikel (refereegranskat)abstract
- A common library, TMDlib2, for Transverse-Momentum-Dependent distributions (TMDs) and unintegrated parton distributions (uPDFs) is described, which allows for easy access of commonly used TMDs and uPDFs, providing a three-dimensional (3D) picture of the partonic structure of hadrons. The tool TMDplotter allows for web-based plotting of distributions implemented in TMDlib2, together with collinear pdfs as available in LHAPDF.
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| 2. |
- Butterworth, J., et al.
(författare)
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Les Houches 2013: Physics at TeV Colliders: Standard Model Working Group Report
- 2014
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Konferensbidrag (refereegranskat)abstract
- This Report summarizes the proceedings of the 2013 Les Houches workshop on Physics at TeV Colliders. Session 1 dealt primarily with (1) the techniques for calculating standard model multi-leg NLO and NNLO QCD and NLO EW cross sections and (2) the comparison of those cross sections with LHC data from Run 1, and projections for future measurements in Run 2.
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| 3. |
- Abdulhamid, M. I., et al.
(författare)
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Azimuthal correlations of high transverse momentum jets at next-to-leading order in the parton branching method
- 2022
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 82:1
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Tidskriftsartikel (refereegranskat)abstract
- The azimuthal correlation, Δ ϕ12, of high transverse momentum jets in pp collisions at s=13 TeV is studied by applying PB-TMD distributions to NLO calculations via MCatNLO together with the PB-TMD parton shower. A very good description of the cross section as a function of Δ ϕ12 is observed. In the back-to-back region of Δ ϕ12→ π, a very good agreement is observed with the PB-TMD Set 2 distributions while significant deviations are obtained with the PB-TMD Set 1 distributions. Set 1 uses the evolution scale while Set 2 uses transverse momentum as an argument in αs, and the above observation therefore confirms the importance of an appropriate soft-gluon coupling in angular ordered parton evolution. The total uncertainties of the predictions are dominated by the scale uncertainties of the matrix element, while the uncertainties coming from the PB-TMDs and the corresponding PB-TMD shower are very small. The Δ ϕ12 measurements are also compared with predictions using MCatNLO together Pythia8, illustrating the importance of details of the parton shower evolution.
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| 4. |
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| 5. |
- Frederix, R., et al.
(författare)
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On the reduction of negative weights in MC@NLO-type matching procedures
- 2020
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Ingår i: Journal of High Energy Physics. - 1126-6708. ; 2020:7
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Tidskriftsartikel (refereegranskat)abstract
- We show how a careful analysis of the behaviour of a parton shower Monte Carlo in the vicinity of the soft and collinear regions allows one to formulate a modified MC@NLO-matching prescription that reduces the number of negative-weight events with respect to that stemming from the standard MC@NLO procedure. As a first practical application of such a prescription, that we dub MC@NLO-∆, we have implemented it in the MadGraph5_aMC@NLO framework, by employing the Pythia8 Monte Carlo. We present selected MC@NLO-∆ results at the 13 TeV LHC, and compare them with MC@NLO ones. We find that the former predictions are consistent with the latter ones within the typical matching systematics, and that the reduction of negative-weight events is significant.
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| 6. |
- van Kampen, A. M., et al.
(författare)
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Boson-jet and jet-jet azimuthal correlations at high transverse momenta
- 2022
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Ingår i: Proceedings of Science. ; 414
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Konferensbidrag (refereegranskat)abstract
- We discuss our recent results on azimuthal distributions in vector boson + jets and multi-jet production at the LHC, obtained from the matching of next-to-leading order (NLO) perturbative matrix elements with transverse momentum dependent (TMD) parton branching. We present a comparative analysis of boson-jet and jet-jet correlations in the back-to-back region, and a study of the theoretical systematic uncertainties associated with the matching scale in the cases of TMD and collinear parton showers.
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| 7. |
- Yang, H., et al.
(författare)
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Back-to-back azimuthal correlations in Z + jet events at high transverse momentum in the TMD parton branching method at next-to-leading order
- 2022
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 82:8
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Tidskriftsartikel (refereegranskat)abstract
- Azimuthal correlations in Z + jet production at large transverse momenta are computed by matching Parton-Branching (PB) TMD parton distributions and showers with NLO calculations via MCatNLO. The predictions are compared with those for dijet production in the same kinematic range. The azimuthal correlations Δ ϕ between the Z boson and the leading jet are steeper compared to those in dijet production at transverse momenta O(100) GeV , while they become similar for very high transverse momenta O(1000) GeV . The different patterns of Z + jet and dijet azimuthal correlations can be used to search for potential factorization-breaking effects in the back-to-back region, which depend on the different color and spin structure of the final states and their interferences with the initial states. In order to investigate these effects experimentally, we propose to measure the ratio of the distributions in Δ ϕ for Z + jet- and multijet production at low and at high transverse momenta, and compare the results to predictions obtained assuming factorization. We examine the role of theoretical uncertainties by performing variations of the factorization scale, renormalization scale and matching scale. In particular, we present a comparative study of matching scale uncertainties in the cases of PB-TMD and collinear parton showers.
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| 8. |
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| 9. |
- Karneyeu, A., et al.
(författare)
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MCPLOTS : A particle physics resource based on volunteer computing
- 2014
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 74:2, s. 1-22
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Tidskriftsartikel (refereegranskat)abstract
- The mcplots.cern.ch web site (mcplots) provides a simple online repository of plots made with high-energy-physics event generators, comparing them to a wide variety of experimental data. The repository is based on the hepdata online database of experimental results and on the rivet Monte Carlo analysis tool. The repository is continually updated and relies on computing power donated by volunteers, via the lhc@home 2.0 platform.
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