| 1. |
- Andersen, J. R., et al.
(författare)
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Small-x phenomenology - Summary of the 3rd Lund small-x workshop in 2004
- 2006
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 48:1, s. 53-105
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Forskningsöversikt (refereegranskat)abstract
- A third workshop on small-x physics, within the Small-x Collaboration, was held in Hamburg in May 2004 with the aim of overviewing recent theoretical progress in this area and summarizing the experimental status.
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| 2. |
- Andersen, JR, et al.
(författare)
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Small-x phenomenology - summary and status 2002
- 2004
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 35:1, s. 67-98
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Forskningsöversikt (refereegranskat)abstract
- A second workshop on small-x physics, within the Small-x Collaboration, was held in Lund in June 2002 with the aim of over-viewing recent theoretical progress in this area and summarizing the experimental status.
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| 3. |
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| 4. |
- Bothmann, Enrico, et al.
(författare)
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A standard convention for particle-level Monte Carlo event-variation weights
- 2023
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Ingår i: SciPost Physics Core. - 2666-9366. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- Streams of event weights in particle-level Monte Carlo event generators are a convenient and immensely CPU-efficient approach to express systematic uncertainties in phenomenology calculations, providing systematic variations on the nominal prediction within a single event sample. But the lack of a common standard for labelling these variation streams across different tools has proven to be a major limitation for event-processing tools and analysers alike. Here we propose a well-defined, extensible community standard for the naming, ordering, and interpretation of weight streams that will serve as the basis for semantically correct parsing and combination of such variations in both theoretical and experimental studies.
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| 5. |
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| 6. |
- Abramowicz, H., et al.
(författare)
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The Physics case for a forward detector upgrade
- 1995
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Ingår i: Future physics at HERA. Proceedings, Workshop, Hamburg, Germany, September 25, 1995-May 31, 1996. Vol. 1, 2.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 7. |
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| 8. |
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| 9. |
- Alwall, J., et al.
(författare)
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A standard format for Les Houches Event Files
- 2007
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Ingår i: Computer Physics Communications. - : Elsevier BV. - 0010-4655. ; 176:4, s. 300-304
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Tidskriftsartikel (refereegranskat)abstract
- A standard file format is proposed to store process and event information, primarily output from partoti-level event generators for further use by general-purpose ones. The information content is identical with what was already defined by the Les Houches Accord five years ago, but then in terms of Fortran commonblocks. This information is embedded in a minimal XML-style structure, for clarity and to simplify parsing.
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| 10. |
- Alwall, J., et al.
(författare)
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Comparative study of various algorithms for the merging of parton showers and matrix elements in hadronic collisions
- 2008
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 53:3, s. 473-500
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Tidskriftsartikel (refereegranskat)abstract
- We compare different procedures for combining fixed-order tree-level matrix-element generators with parton showers. We use the case of W-production at the Tevatron and the LHC to compare different implementations of the so-called CKKW and MLM schemes using different matrix-element generators and different parton cascades. We find that although similar results are obtained in all cases, there are important differences.
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| 11. |
- Andersen, Jeppe, et al.
(författare)
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A Parton Shower for High Energy Jets
- 2011
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Ingår i: Journal of High Energy Physics. - 1029-8479. ; 2011:7, s. 1-23
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Tidskriftsartikel (refereegranskat)abstract
- We present a method to match the multi-parton states generated by the High Energy Jets Monte Carlo with parton showers generated by the A riadne program using the colour dipole model. The High Energy Jets program already includes a full resummation of soft divergences. Hence, in the matching it is important that the corresponding divergences in the parton shower are subtracted, keeping only the collinear parts. We present a novel, shower-independent method for achieving this, enabling us to generate fully exclusive and hadronized events with multiple hard jets, in hadronic collisions. We discuss in detail the arising description of the soft, collinear and hard regions by examples in pure QCD jet-production.
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| 12. |
- Andersen, Jeppe R., et al.
(författare)
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Les Houches 2017: Physics at TeV Colliders Standard Model Working Group Report
- 2018. - 07977
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- This Report summarizes the proceedings of the 2017 Les Houches workshop on Physics at TeV Colliders. Session 1 dealt with (I) new developments relevant for high precision Standard Model calculations, (II) theoretical uncertainties and dataset dependence of parton distribution functions, (III) new developments in jet substructure techniques, (IV) issues in the theoretical description of the production of Standard Model Higgs bosons and how to relate experimental measurements, (V) phenomenological studies essential for comparing LHC data from Run II with theoretical predictions and projections for future measurements, and (VI) new developments in Monte Carlo event generators.
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| 13. |
- Andersen, Jeppe R., et al.
(författare)
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Merging high energy with soft and collinear logarithms using HEJ and PYTHIA
- 2018
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Ingår i: Journal of High Energy Physics. - 1029-8479. ; 2018:9
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Tidskriftsartikel (refereegranskat)abstract
- We present a method to combine the all-order treatment of the High Energy Jets exclusive partonic Monte Carlo (HEJ) with the parton shower of Pythia8, while retaining the logarithmic accuracy of both. This procedure enables the generation of fully realistic and hadronised events with HEJ. Furthermore, the combination of the two allorder treatments leads to improvements in the quality of the description of observables, in particular for regions with disparate transverse scales.
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| 14. |
- Andersson, Bo, et al.
(författare)
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Small x phenomenology: summary and status
- 2002
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 25:1, s. 77-101
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Forskningsöversikt (refereegranskat)abstract
- The aim of this paper is to summarize the general status of our understanding of small-x physics. It is based on presentations and discussions at an informal meeting OIL this topic held in Lund, Sweden, in March 2001. This document also marks the founding of an informal collaboration between experimentalists and theoreticians with a special interest in small-x physics. This paper is dedicated to the memory of Bo Andersson. who died unexpectedly from a heart attack on March 4th, 2002.
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| 15. |
- Aurenche, P., et al.
(författare)
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Gamma gamma physics
- 1996
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Ingår i: 2nd CERN Workshop on LEP2 Physics Geneva, Switzerland, June 15-16, 1995. ; , s. 291-348
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Konferensbidrag (refereegranskat)
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| 16. |
- Avsar, Emil, et al.
(författare)
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Diffractive Excitation in DIS and pp Collisions
- 2007
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Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479. ; 0712:012
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Tidskriftsartikel (refereegranskat)abstract
- We have in earlier papers presented an extension of Mueller's dipole cascade model, which includes subleading effects from energy conservation and running coupling as well as colour suppressed effects from pomeron loops via a ``dipole swing''. The model was applied to describe the total cross sections in pp and gamma*p collisions. In this paper we present a number of improvements of the model, in particular related to the confinement mechanism. A consistent treatment of dipole evolution and dipole--dipole interactions is achieved by replacing the infinite range Coulomb potential by a screened potential, which further improves the frame-independence of the model. We then apply the model to elastic scattering and diffractive excitation, where we specifically study the effects of different sources for fluctuations. In our formalism we can take into account contributions from all different sources, from the dipole cascade evolution, the dipole--dipole scattering, from the impact-parameter dependence, and from the initial photon and proton wavefunctions. Good agreement is obtained with data from the Tevatron and from HERA, and we also present some predictions for the LHC.
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| 17. |
- Avsar, Emil, et al.
(författare)
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Energy conservation and saturation in small-x evolution
- 2005
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Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479. ; :7
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Tidskriftsartikel (refereegranskat)abstract
- Important corrections to BFKL evolution are obtained from non-leading contributions and from non-linear effects due to unitarisation or saturation. It has been diffcult to estimate the relative importance of these effects, as NLO effects are most easily accounted for in momentum space while unitarisation and saturation are easier in transverse coordinate space. An essential component of the NLO contributions is due to energy conservation effects, and in this paper we present a model for implementing such effects together with saturation in Mueller's dipole evolution formalism. We find that energy conservation severely dampens the small-x rise of the gluon density and, as a consequence, the onset of saturation is delayed. Using a simple model for the proton we obtain a reasonable qualitative description of the x-dependence of F-2 at low Q(2) as measured at HERA even without saturation effects. We also give qualitative descriptions of the energy dependence of the cross section for gamma*gamma* and gamma*-nucleus scattering.
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| 18. |
- Avsar, Emil, et al.
(författare)
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Small-x dipole evolution beyond the large-N-c limit
- 2007
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Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479. ; :1
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Tidskriftsartikel (refereegranskat)abstract
- We present a method to include colour-suppressed effects in the Mueller dipole picture. The model consistently includes saturation effects both in the evolution of dipoles and in the interactions of dipoles with a target in a frame-independent way. When implemented in a Monte Carlo simulation together with our previous model of energy-momentum conservation and a simple dipole description of initial state protons and virtual photons, the model is able to reproduce to a satisfactory degree both the gamma*p cross sections as measured at HERA as well as the total pp cross section all the way from ISR energies to the Tevatron and beyond.
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| 19. |
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| 20. |
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| 21. |
- Barlow, R., et al.
(författare)
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Report of the heavy flavors working group
- 1991
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Ingår i: Journal of Physics G: Nuclear and Particle Physics. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 17:10, s. 1605-1623
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- After a brief discussion of the statistics available to the four LEP experiments at the time of writing and an overview of B-event characteristics, the authors consider in particular the theory, practice and potential pitfalls of neural networks, a new approach to B tagging which attracted a great deal of interest. They then consider some of the QCD aspects of heavy flavour physics. Finally there is a brief discussion of the prospects for heavy flavour physics at HERA.
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| 22. |
- Bertini, Marc, et al.
(författare)
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PYTHIA version 7-0.0 - a proof-of-concept version
- 2001
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Ingår i: Computer Physics Communications. - 0010-4655. ; 134:3, s. 365-391
-
Tidskriftsartikel (refereegranskat)abstract
- This document describes the first proof-of-concept version of the PYTHIA7 program. PYTHIA7 is a complete re-write of the PYTHIA program in C++. It is mainly intended to be a replacement for the `Lund' family of event generators, but is also a framework with a structure suitable for implementing any event generator model. In this document, the structure of the program is presented both from the user and the developer point of view. It is not intended to be a complete manual, but together with the documentation provided in the distribution, it should be sufficient to start working with the program.
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| 23. |
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| 24. |
- Bierlich, Christian, et al.
(författare)
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Collectivity without plasma in hadronic collisions
- 2018
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Ingår i: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 779, s. 58-63
-
Tidskriftsartikel (refereegranskat)abstract
- We present a microscopic model for collective effects in high multiplicity proton–proton collisions, where multiple partonic subcollisions give rise to a dense system of strings. From lattice calculations we know that QCD strings are transversely extended, and we argue that this should result in a transverse pressure and expansion, similar to the flow in a deconfined plasma. The model is implemented in the PYTHIA8 Monte Carlo event generator, and we find that it can qualitatively reproduce the long range azimuthal correlations forming a near-side ridge in high multiplicity proton–proton events at LHC energies.
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| 25. |
- Bierlich, Christian, et al.
(författare)
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Confronting experimental data with heavy-ion models : Rivet for heavy ions
- 2020
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 80:5
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Tidskriftsartikel (refereegranskat)abstract
- The Rivet library is an important toolkit in particle physics, and serves as a repository for analysis data and code. It allows for comparisons between data and theoretical calculations of the final state of collision events. This paper outlines several recent additions and improvements to the framework to include support for analysis of heavy ion collision simulated data. The paper also presents examples of these recent developments and their applicability in implementing concrete physics analyses.
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