| 1. |
- Sahoo, Baidyanath, et al.
(författare)
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Simulation Studies of R2(Δ η, Δ ϕ) and P2(Δ η, Δ ϕ) Correlation Functions in pp Collisions with the PYTHIA and HERWIG Models
- 2022
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Ingår i: Proceedings of the 24th DAE-BRNS High Energy Physics Symposium, 2020. - Singapore : Springer Nature Singapore. - 0930-8989 .- 1867-4941. - 9789811923531 ; 277, s. 349-352
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Konferensbidrag (refereegranskat)abstract
- We presented a study of charge-independent (CI) and charge-dependent (CD) two-particle differential number correlation functions R2 and transverse momentum correlation functions P2 in pp collisions at s=2.76 TeV with the PYTHIA and HERWIG models.Calculations were presented for unidentified hadrons in three pT ranges 0.2 < pT≤ 2.0 GeV/c, 2.0 < pT≤ 5.0 GeV/c, and 5.0 < pT≤ 30.0 GeV/c.PYTHIA and HERWIG both qualitatively reproduce the near-side peak and away-side ridge correlation features reported by experiments.At low pT, both models produce narrower near-side peaks in P2 correlations than in R2 as reported by the ALICE collaboration in p–Pb and Pb–Pb collisions.This suggests that the narrower shape of the P2 near-side peak is largely determined by the pT dependent angular ordering of hadrons produced in jets.Both PYTHIA and HERWIG predict widths that decrease with increasing pT.Widths extracted for P2 correlators are typically significantly narrower than those of the R2 counterparts [1].
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| 2. |
- Andreasson, Håkan, 1966
(författare)
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Black hole formation from a complete past for the einstein–vlasov system
- 2014
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Ingår i: International conference on Relativity and Gravitation, 2012, Prague, Czech Republic, 25-29 June 2012. - Cham : Springer International Publishing. - 0930-8989 .- 1867-4941. - 9783319067605 ; 157, s. 11-18
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Konferensbidrag (refereegranskat)abstract
- Anatural question in general relativity is to find initial data for the Einstein equations whose past evolution is regular and whose future evolution contains a black hole. In [1] initial data of this kind is constructed for the spherically symmetric Einstein–Vlasov system. One consequence of the result is that there exists a class of initial data for which the ratio of the Hawking mass (Formula presented) (r) and the area radius r is arbitrarily small everywhere, such that a black hole forms in the evolution. This result is analogous to the result [2] for a scalar field. Another consequence is that there exist black hole initial data such that the solutions exist for all Schwarzschild time t ∈ (−∞,∞). In the present article we review the results in [1].
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| 3. |
- Bandyopadhyay, Triparno, et al.
(författare)
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Notes on a Z′
- 2021
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Ingår i: XXIII DAE High Energy Physics Symposium - Select Proceedings. - Singapore : Springer Nature Singapore. - 1867-4941 .- 0930-8989. - 9789813344075 ; 261, s. 175-180
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Konferensbidrag (refereegranskat)abstract
- We reexamine anomaly free U(1) extensions of the standard model in the light of LHC Drell-Yan data, constraints from unitarity, and neutrino-electron scattering to put model-independent bounds in the parameter space populated by MZ′, the Z- Z′ mixing angle (αz ), and the extra U(1) effective gauge coupling (gx′ ). We propose a formalism where any model dependence is absorbed into these three parameters.
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| 4. |
- Cederwall, Martin, 1961
(författare)
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Pure spinor superfields - an overview
- 2014
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Ingår i: Springer Proceedings in Physics. - Cham : Springer International Publishing. - 0930-8989 .- 1867-4941. ; 153, s. 61-93
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Konferensbidrag (refereegranskat)abstract
- Maximally supersymmetric theories do not allow off-shell superspace formulations with traditional superfields containing a finite set of auxiliary fields. It has become clear that off-shell supersymmetric action formulations of such models can be achieved by the introduction of pure spinors. In this talk, an overview of this formalism is given, with emphasis on D=10 super-Yang-Mills theory and D=11 supergravity. This a somewhat expanded version of a talk presented at the workshop "Breaking of supersymmetry and ultraviolet divergences in extended supergravity" (BUDS), Laboratori Nazionali di Frascati, March 25-28, 2013.
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| 5. |
- Ekström, Andreas, 1980
(författare)
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Strong Interactions for Precision Nuclear Physics
- 2020
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Ingår i: Springer Proceedings in Physics. - Cham : Springer International Publishing. - 0930-8989 .- 1867-4941. ; 238, s. 549-558
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Konferensbidrag (refereegranskat)abstract
- One of the key challenges in ab initio nuclear theory is to understand the emergence of nuclear structure from quantum chromodynamics. I will address this challenge and focus on the statistical aspects of uncertainty quantification and parameter estimation in chiral effective field theory.
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| 6. |
- Golub, Mikhail, 1982, et al.
(författare)
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Modelling of elastic wave propagation through damaged interface via effective spring boundary conditions
- 2018
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Ingår i: Springer Proceedings in Physics. - Cham : Springer International Publishing. - 0930-8989 .- 1867-4941. ; 207, s. 375-387
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Konferensbidrag (refereegranskat)abstract
- The present work deals with the application of spring boundary conditions in order to describe elastic wave propagation in composites with damaged interfaces. Dynamic behaviour of the damaged zone is described by means of a distribution of micro-cracks and introduction of spring boundary conditions, where stresses are proportional to the jump in displacement along the damaged interface and the proportionality factor is the distributed spring stiffness. The stiffness in the spring boundary conditions is determined from the equivalence of the transmission coefficients for these two models. As a result, the normal and tangential components of the spring stiffness tensor depend on the concentration of the defects, their typical size and elastic properties of the contacting materials. The three-dimensional problem with elastic wave scattering by a random or periodic distribution of rectangular microcracks is considered, the latter with a boundary integral equation method. The transmission through the damaged interface with random and periodic distribution of rectangular cracks is compared with a good correspondence giving confidence that the models are appropriate.
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| 7. |
- Hansson, Thors Hans, et al.
(författare)
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Effective field theories for topological states of matter
- 2020
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Ingår i: Springer Proceedings in Physics. - Cham : Springer. - 0930-8989 .- 1867-4941. ; 239, s. 1-68
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Tidskriftsartikel (refereegranskat)abstract
- Since the discovery of the quantum Hall effect in the 1980s it has been clear that there exists states of matter characterized by subtle quantum mechanical effects that renders certain properties surprisingly stable against dirt and noise. The theoretical understanding of these topological quantum phases have continued to develop during the last few decades and it has really surged after the discovery of the time-reversal invariant topological insulators. There are many examples of topological phases that have been important for the theoretical understanding of topological states of matter as well as being of great physical relevance. In this chapter we will focus on some examples that we find particularly enlightening and relevant, but we will not make a complete classification. Some of the most important tools for the understanding of topological quantum matter are based on effective field theory methods. We shall employ two different types of effective field theories. The first, which is valid at intermediate length and time-scales, will not capture the physics at microscopic scales. Such theories are the analogs, for topological phases, of the Ginzburg–Landau theories used to describe the usual symmetry breaking non-topological phases. The second type of theories describe the physics on scales where non-topological gapped states would be very boring, namely at distances and times much larger than the correlation length and the time set by the inverse gap. On these scales everything is independent of any distance and the theories will be topological field theories, which do not describe any dynamics in the bulk, but do carry information about topological properties of the excitations, and also about excitations at the boundaries of the system. Finally, we will also study effective response actions. In a strict sense these are not effective theories, since they do not have any dynamical content, but encode the response of the system to external perturbations, typically an electromagnetic field. As we shall see, however, the effective response action for topological states can be used to extract parts of the dynamic theory through a method called functional bosonization.
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| 8. |
- Hernandez, O. J., et al.
(författare)
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A Statistical Analysis of the Nuclear Structure Uncertainties in μD
- 2020
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Ingår i: Springer Proceedings in Physics. - Cham : Springer International Publishing. - 0930-8989 .- 1867-4941. ; 238, s. 833-837
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Konferensbidrag (refereegranskat)abstract
- The charge radius of the deuteron (D), was recently determined to three times the precision compared with previous measurements using the measured Lamb shift in muonic deuterium ((formula presented)D). However, the (formula presented)D value is 5.6 (formula presented) smaller than the world averaged CODATA-2014 value (Pohl R et al. (2016) Science 353:669 [1]). To shed light on this discrepancy we analyze the uncertainties of the nuclear structure calculations of the Lamb shift in (formula presented)D and conclude that nuclear theory uncertainty is not likely to be the source of the discrepancy.
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| 9. |
- Karlsson, Anna, 1987
(författare)
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Loop amplitude diagrams in manifest, maximal supergravity
- 2014
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Ingår i: Springer Proceedings in Physics. - Cham : Springer International Publishing. - 0930-8989 .- 1867-4941.
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Konferensbidrag (refereegranskat)abstract
- The issue of finiteness of maximal supergravity has been subject to research for quite some time. Here, we approach that question through an examination of how to describe amplitude diagrams in D=11 maximal supergravity from a field theory point of view. The strength of the formulation is the presence of manifest supersymmetry through the use of pure spinors. An initial analysis of what the subsequent characteristics turn out to be, partly in lower dimensions through dimensional reduction, gives at hand results that agree with previous work, pointing towards a first divergence for the 7-loop contribution to the 4-point amplitude in four dimensions. The text is mainly based on [arXiv:1212.5175] and may be regarded as an introduction to the main points presented there.
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| 10. |
- Kleinhans, David, 1979, et al.
(författare)
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Synthetic turbulence models for wind turbine applications
- 2010
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Ingår i: Springer Proceedings in Physics. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 0930-8989 .- 1867-4941. ; 131, s. 111-114
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Konferensbidrag (refereegranskat)abstract
- Wind energy converters such as wind turbines permanently work in the atmospheric boundary layer. For the modelling of the dynamics and for the optimisation of design and material of wind turbines synthetic models for atmospheric turbulence are applied already for a long time. The main purpose of these models is to provide fast and efficient methods for numerical simulation of random fields, that show some characteristic features of atmospheric turbulence. Typically they only have a partial connection to the fundamental equations of fluid dynamics. After a short overview summarizing widespread models by Veers and Mann, that are based on the simulation of random fields in the Fourier domain, advanced models for the simulation of velocity fields are discussed.
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