| 1. |
- Bellm, Johannes, et al.
(författare)
-
PISTA: Posterior Ion STAcking
- 2018
-
Ingår i: ArXiv e-prints.
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- We present a program allowing for the construction of a heavy ion Monte Carlo event using a general purpose proton–proton event generator of the users’ choice to deliver sub–collisions. In this heavy ion event, one or more jets can be added, again using a jet calculation of the users’ choice, allowing for more realistic simulation studies of jets in a heavy ion background.
|
|
| 2. |
- Bierlich, Christian, et al.
(författare)
-
Collectivity without plasma in hadronic collisions
- 2018
-
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.
|
|
| 3. |
- Bierlich, Christian, et al.
(författare)
-
Future physics opportunities for high-density QCD at the LHC with heavy-ion and proton beams
- 2018
-
Ingår i: Future physics opportunities for high-density QCD at the LHC with heavy-ion and proton beams.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The future opportunities for high-density QCD studies with ion and proton beams at the LHC are presented. Four major scientific goals are identified: the characterisation of the macroscopic long wavelength Quark-Gluon Plasma (QGP) properties with unprecedented precision, the investigation of the microscopic parton dynamics underlying QGP properties, the development of a unified picture of particle production and QCD dynamics from small (pp) to large (nucleus--nucleus) systems, the exploration of parton densities in nuclei in a broad (x, Q2) kinematic range and the search for the possible onset of parton saturation. In order to address these scientific goals, high-luminosity Pb-Pb and p-Pb programmes are considered as priorities for Runs 3 and 4, complemented by high-multiplicity studies in pp collisions and a short run with oxygen ions. High-luminosity runs with intermediate-mass nuclei, for example Ar or Kr, are considered as an appealing case for extending the heavy-ion programme at the LHC beyond Run 4. The potential of the High-Energy LHC to probe QCD matter with newly-available observables, at twice larger center-of-mass energies than the LHC, is investigated.
|
|
| 4. |
|
|
| 5. |
- Bierlich, Christian
(författare)
-
Rope Hadronization and Strange Particle Production
- 2018
-
Ingår i: 17th International Conference on Strangeness in Quark Matter, SQM 2017. - : EDP Sciences. - 9782759890330 ; 171
-
Konferensbidrag (refereegranskat)abstract
- Rope Hadronization is a model extending the Lund string hadronization model to describe environments with many overlapping strings, such as high multiplicity pp collisions or AA collisions. Including effects of Rope Hadronization drastically improves description of strange/non-strange hadron ratios as function of event multiplicity in all systems from e+e- to AA. Implementation of Rope Hadronization in the MC event generators Dipsy and Pythia8 is discussed, as well as future prospects for jet studies and studies of small systems.
|
|
| 6. |
- Bierlich, Christian, et al.
(författare)
-
The Angantyr model for heavy-ion collisions in Pythia8
- 2018
-
Ingår i: Journal of High Energy Physics. - 1029-8479. ; 2018:10
-
Tidskriftsartikel (refereegranskat)abstract
- We present a new model for building up complete exclusive hadronic final states in high energy nucleus collisions. It is a direct extrapolation of high energy pp collisions (as described by Pythia), and thus bridges a large part of the existing gap between heavy ion and high energy physics phenomenology. The model is inspired by the old Fritiof model and the notion of wounded nucleons. Two essential features are the treatment of multi-parton interactions and diffractive excitation in each NN sub-collision. Diffractive excitation is related to fluctuations in the nucleon partonic sub-structure, and fluctuations in both projectile and target are here included for the first time. The model is able to give a good description of general final-state properties such as multiplicity and transverse momentum distributions, both in pA and AA collisions. The model can therefore serve as a baseline for understanding the non-collective background to observables sensitive to collective behaviour. As Pythia does not include a mechanism to reproduce the collective effects seen in pp collisions, such effects are also not reproduced by the present version of Angantyr. Effects of high string density, shown to be able to reproduce e.g. higher strangeness ratios and the ridge in pp, will be added in future studies.
|
|
