Mathematics / Matematik

Permanent URI for this collectionhttps://hdl.handle.net/11147/8

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Start date: 2020Publication Index: search.filters.publicationIndex.PubMed

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  • Article
    Citation - WoS: 27
    Citation - Scopus: 31
    Development and Validation of Herwig 7 Tunes From Cms Underlying-Event Measurements
    (Springer, 2021) Karapınar, Güler
    This paper presents new sets of parameters (tunes) for the underlying-event model of the herwig 7 event generator. These parameters control the description of multiple-parton interactions (MPI) and colour reconnection in herwig 7, and are obtained from a fit to minimum-bias data collected by the CMS experiment at v s = 0.9, 7, and 13 TeV. The tunes are based on the NNPDF3.1 next-to-nextto-leading-order parton distribution function (PDF) set for the parton shower, and either a leading-order or next-to-nextto-leading-order PDF set for the simulation of MPI and the beam remnants. Predictions utilizing the tunes are produced for event shape observables in electron-positron collisions, and forminimum-bias, inclusive jet, top quark pair, and Zand Wboson events in proton-proton collisions, and are compared with data. Each of the new tunes describes the data at a reasonable level, and the tunes using a leading-order PDF for the simulation of MPI provide the best description of the data.
  • Article
    Citation - WoS: 9
    Citation - Scopus: 15
    Constraints on the Initial State of Pb-Pb Collisions Via Measurements of Z-Boson Yields and Azimuthal Anisotropy at Root S(nn)=5.02 Tev
    (Amer Physical Soc, 2021) Karapınar, Güler; CMS Collaboration
    The CMS experiment at the LHC has measured the differential cross sections of Z bosons decaying to pairs of leptons, as functions of transverse momentum and rapidity, in lead-lead collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV. The measured Z boson elliptic azimuthal anisotropy coefficient is compatible with zero, showing that Z bosons do not experience significant final-state interactions in the medium produced in the collision. Yields of Z bosons are compared to Glauber model predictions and are found to deviate from these expectations in peripheral collisions, indicating the presence of initial collision geometry and centrality selection effects. The precision of the measurement allows, for the first time, for a data-driven determination of the nucleon-nucleon integrated luminosity as a function of lead-lead centrality, thereby eliminating the need for its estimation based on a Glauber model.
  • Article
    Citation - WoS: 22
    Citation - Scopus: 20
    Fokas Method for Linear Boundary Value Problems Involving Mixed Spatial Derivatives
    (Royal Society of Chemistry, 2020) Fokas, A. S.; Batal, Ahmet; Özsarı, Türker
    We obtain solution representation formulae for some linear initial boundary value problems posed on the half space that involve mixed spatial derivative terms via the unified transform method (UTM), also known as the Fokas method. We first implement the method on the second-order parabolic PDEs; in this case one can alternatively eliminate the mixed derivatives by a linear change of variables. Then, we employ the method to biharmonic problems, where it is not possible to eliminate the cross term via a linear change of variables. A basic ingredient of the UTM is the use of certain invariant maps. It is shown here that these maps are well defined provided that certain analyticity issues are appropriately addressed.