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- Sjöstrand, Torbjörn, et al.
(författare)
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Baryon number violation and string topologies
- 2003
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Ingår i: Nuclear Physics, Section B. - 0550-3213. ; 659:1-2, s. 243-298
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Tidskriftsartikel (refereegranskat)abstract
- In supersymmetric scenarios with broken R-parity, baryon number violating sparticle decays become possible. In order to search for such decays, a good understanding of expected event properties is essential. We here develop a complete framework that allows detailed studies. Special attention is given to the hadronization phase, wherein the baryon number violating vertex is associated with the appearance of a junction in the colour confinement field. This allows us to tell where to look for the extra (anti)baryon directly associated with the baryon number violating decay. (C) 2003 Elsevier Science B.V. All rights reserved.
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| 4. |
- Sjöstrand, T., et al.
(författare)
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Multiple interactions and beam remnants
- 2004
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Ingår i: Physics at TeV colliders. Proceedings, Workshop, Les Houches, France, May 26-June 3, 2003.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 5. |
- Sjöstrand, Torbjörn, et al.
(författare)
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Multiple interactions and the structure of beam remnants
- 2004
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Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479. ; :3
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Tidskriftsartikel (refereegranskat)abstract
- Recent experimental data have established some of the basic features of multiple interactions in hadron-hadron collisions. The emphasis is therefore now shifting, to one of exploring more detailed aspects. Starting from a brief review of the current situation, a next-generation model is developed, wherein a detailed account is given of correlated flavour, colour, longitudinal and transverse momentum distributions, encompassing both the partons initiating perturbative interactions and the partons left in the beam remnants. Some of the main features are illustrated for the Tevatron and the LHC.
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| 6. |
- Skands, Peter
(författare)
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Phenomenological Studies on Supersymmetry and the Strong Force
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis, we first consider the phenomenology of R-parity violating supersymmetric extensions of the Standard Model. Specifically, a large number of Lepton and Baryon Number violating decays of sparticles to particles are implemented in the Pythia event generator. The augmented generator has then been used to study event properties of these models, mainly at the LHC. During these studies, the development of the so-called SuSy Les Houches Accord opened for an easier interfacing between SuSy calculational tools. A first `proof-of-concept' application of the Accord was to input SuSy spectra and decay tables calculated by the SPheno program into Pythia, for the purpose of determining whether experiments at the LHC will be sensitive to a connection between neutrino mixing and SuSy with bilinear Lepton Number violation. For the case of Baryon Number violation, an extension of the Lund String Model to colour topologies involving explicit Baryon Numbers is developed, called `junction fragmentation', which enables us to trace the migration of the generated Baryon number in some detail. This model is then itself extended and applied to improve the description of the physics of beam remnants in hadron--hadron collisions, in the context of a new framework for minimum-bias and underlying events. Based on the idea of multiple perturbative parton--parton interactions in hadron collisions, a sophisticated treatment of correlations in impact parameter, flavour, momentum, and colour is introduced. The last step so far in the evolution of this model has been the development of pT-ordered initial- and final-state radiation algorithms, which among other things have enabled us to `interleave' initial-state radiation and multiple interactions into one common sequence of decreasing pT values. Nonetheless, there is still a long way to go before a clear and unique picture of hadron collisions may emerge.
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| 8. |
- Skands, Peter
(författare)
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Searching for L-violating supersymmetry at the LHC
- 2002
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 23:1, s. 173-184
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Tidskriftsartikel (refereegranskat)abstract
- The possibility to simulate lepton number violating supersymmetric models has been introduced into the recently updated Pythia event generator, now containing 1278 decay channels of SUSY particles into SM particles via lepton number violating interactions. This generator has been used in combination with the AtlFast detector simulation to study the impact of lepton number violation (4) on event topologies in the ATLAS detector, and trigger menus designed for L-SUSY are proposed based on very general considerations. In addition. a rather preliminary analysis is presented on the possibility for ATLAS to observe a signal above the background in several mSUGRA scenarios, using a combination of primitive cuts and neural networks to optimize the discriminating power between signal and background events over regions of parameter space rather than at individual points. It is found that a 5sigma discovery is possible roughly for m(1/2) < 1 TeV and m(0) < 2TeV with an integrated luminosity of 30fb(-1), corresponding to one year of data taking with the LHC running at "mid-luminosity", L = 3 x 10(33) cm(-2)s(-1).
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| 9. |
- Skands, Peter, et al.
(författare)
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SUSY Les Houches accord: interfacing SUSY spectrum calculators, decay packages, and event generators
- 2004
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Ingår i: Journal of High Energy Physics. - 1029-8479. ; :7
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Tidskriftsartikel (refereegranskat)abstract
- An accord specifying a unique set of conventions for supersymmetric extensions of the Standard Model together with generic file structures for 1) supersymmetric model specifications and input parameters, 2) electroweak scale supersymmetric mass and coupling spectra, and 3) decay tables is presented, to provide a universal interface between spectrum calculation programs, decay packages, and high energy physics event generators.
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