Search results for "Fragmentation Functions"
showing 10 items of 144 documents
"Table 70" of "Measurement of jet fragmentation in Pb+Pb and $pp$ collisions at $\sqrt{s_{NN}} = 5.02$ TeV with the ATLAS detector"
2019
The ratio of the D(z) in different centrality intervals in PbPb and in pp for 199.53 < pTjet < 251.19 and 0.0 < eta < 2.1.
"Table 2" of "Measurement of jet fragmentation in Pb+Pb and $pp$ collisions at $\sqrt{s_{NN}} = 5.02$ TeV with the ATLAS detector"
2020
The ratio of the D(z) in different centrality intervals in PbPb and in pp for 126.00 < pTjet < 158.49 and 0.0 < eta < 2.1.
"Table 42" of "Measurement of jet fragmentation in Pb+Pb and $pp$ collisions at $\sqrt{s_{NN}} = 5.02$ TeV with the ATLAS detector"
2020
The ratio of the D(z) in different centrality intervals in PbPb and in pp for 158.49 < pTjet < 199.53 and 0.3 < eta < 0.8.
"Table 38" of "Measurement of jet fragmentation in Pb+Pb and $pp$ collisions at $\sqrt{s_{NN}} = 5.02$ TeV with the ATLAS detector"
2020
The ratio of the D(z) in different centrality intervals in PbPb and in pp for 158.49 < pTjet < 199.53 and 0.0 < eta < 0.3.
"Table 82" of "Measurement of jet fragmentation in Pb+Pb and $pp$ collisions at $\sqrt{s_{NN}} = 5.02$ TeV with the ATLAS detector"
2020
The ratio of the D(z) in different centrality intervals in PbPb and in pp for 251.19 < pTjet < 316.22 and 1.2 < eta < 2.1.
Probing the small- x nuclear gluon distributions with isolated photons at forward rapidities in p+Pb collisions at the LHC
2014
Inclusive direct photon production in p+Pb collisions at the LHC is studied within the NLO perturbative QCD. Our aim is to quantify the dominant $x$ regions probed at different rapidities and to identify the best conditions for testing the nuclear gluon parton distribution functions (nPDFs) at small $x$. A comparison to the inclusive pion production reveals that from these two processes the photons carry more sensitivity to the small-$x$ partons and that this sensitivity can be further increased by imposing an isolation cut for the photon events. The details of the isolation criteria, however, seem to make only a small difference to the studied $x$ sensitivity and have practically no effect…
Extracting the impact parameter dependence of the nPDFs from the EKS98 and EPS09 global fits
2013
As all the globally fitted nuclear PDFs (nPDFs) have been so far impact parameter independent, it has not been possible to calculate the hard process cross sections in different centrality classes consistently with the global analyses. In \cite{Helenius:2012wd} we have offered a solution to this problem by determining two spatially dependent nPDF sets, \texttt{EPS09s} and \texttt{EKS98s}, using the $A$-systematics of the earlier global fits EPS09 and EKS98 and an assumption that the spatial dependence can be written as a power series of the nuclear thickness function. For a data comparison, we have calculated the nuclear modification factor of inclusive neutral pion production in d+Au colli…
Studies of QCD at $e^{+}e^{-}$ centre-of-mass energies between 91 and 209 GeV
2004
The hadronic final states observed with the ALEPH detector at LEP in e(+)e(-) annihilation are analysed using 730 pb(-1) of data collected between 91 and 209 GeV in the framework of QCD. In particular event-shape variables and inclusive charged particle spectra are measured. The energy evolution of quantities derived from these measurements is compared to analytic QCD predictions. The mean charged particle multiplicity, the charged particle momentum spectrum and its peak position are compared to predictions of the modified-leading-logarithmic approximation. The strong coupling constant alpha(s) is determined from a fit of the QCD prediction to distributions of six event-shape variables at e…
DETERMINATION OF ALPHA(S) FOR B-QUARKS AT THE Z(0) RESONANCE
1993
The strong coupling constant for b quarks has been determined, and its flavour independence, as predicted by QCD, investigated. The analysis involved events with lepton candidates selected from approximately 356 000 hadronic decays of the Z0, collected by the DELPHI detector at LEP in 1990 and 199 1. A method based on a direct comparison of the three-jet fraction in a b enriched sample, selected by requiring leptons with large momenta and transverse momenta, to that of the entire hadronic sample, illustrated the significant effect of the b quark mass on the multi-jet cross section, and verified the flavour independence of the strong coupling constant to an accuracy of +/- 6%. A second proce…
A measurement of αs from the scaling violation in e+e- annihilation
1997
The hadronic fragmentation functions of the various quark flavours and of gluons are measured in a study of the inclusive hadron production from $\zz$ decays with the DELPHI detector and are compared with the fragmentation functions measured elsewhere at energies between 14 GeV and 91 GeV. A large scaling violation is observed, which is used to extract the strong coupling constant from a fit using a numerical integration of the second order DGLAP evolution equations. The result is \begin{displaymath} \alpha_s(M_Z) = 0.124^{+0.006}_{-0.007}(exp)\pm 0.009 (theory) \end{displaymath} where the first error represents the experimental uncertainty and the second error is due to the factorization a…