Non-quadratic improved Hessian PDF reweighting and application to CMS dijet measurements at 5.02 TeV
Eskola, K., Paakkinen, P., & Paukkunen, H. (2019). Non-quadratic improved Hessian PDF reweighting and application to CMS dijet measurements at 5.02 TeV. European Physical Journal C, 79(6), Article 511. https://doi.org/10.1140/epjc/s10052-019-6982-2
Published in
European Physical Journal CDate
2019Copyright
© The Author(s) 2019.
Hessian PDF reweighting, or “profiling”, has
become a widely used way to study the impact of a new
data set on parton distribution functions (PDFs) with Hessian
error sets. The available implementations of this method have
resorted to a perfectly quadratic approximation of the initial
χ2 function before inclusion of the new data. We demonstrate how one can take into account the first non-quadratic
components of the original fit in the reweighting, provided
that the necessary information is available. We then apply
this method to the CMS measurement of dijet pseudorapidity spectra in proton–proton (pp) and proton–lead (pPb) collisions at 5.02 TeV. The measured pp dijet spectra disagree
with next-to-leading order (NLO) theory calculations using
the CT14 NLO PDFs, but upon reweighting the CT14 PDFs,
these can be brought to a much better agreement. We show
that the needed proton-PDF modifications also have a significant impact on the predictions for the pPb dijet distributions. Taking the ratio of the individual spectra, the protonPDF uncertainties effectively cancel, giving a clean probe
of the PDF nuclear modifications. We show that these data
can be used to further constrain the EPPS16 nuclear PDFs
and strongly support gluon nuclear shadowing at small x and
antishadowing at around x ≈ 0.1.
...


Publisher
SpringerISSN Search the Publication Forum
1434-6044Keywords
Publication in research information system
https://converis.jyu.fi/converis/portal/detail/Publication/31217956
Metadata
Show full item recordCollections
Related funder(s)
Academy of FinlandFunding program(s)
Research post as Academy Research Fellow, AoF; Academy Project, AoF
Additional information about funding
We thank Yen-Jie Lee for discussions. We have received funding from the Academy of Finland, Project 297058 of K.J.E. and 308301 of H.P.; P.P. acknowledges the financial support from the Magnus Ehrnrooth Foundation. We thank the Finnish IT Center for Science (CSC) for the computational resources allocated under the Project jyy2580.License
Related items
Showing items with similar title or keywords.
-
Jet fragmentation transverse momentum distributions in pp and p-Pb collisions at √s, √sNN = 5.02 TeV
ALICE collaboration (Springer, 2021) -
Charged-particle multiplicity distributions over a wide pseudorapidity range in proton-proton collisions at s√= 0.9, 7, and 8 TeV
ALICE Collaboration (Springer, 2017)We present the charged-particle multiplicity distributions over a wide pseudorapidity range (−3.4<η<5.0) for pp collisions at s√=0.9,7, and 8 TeV at the LHC. Results are based on information from the Silicon Pixel Detector ... -
Applicability of pion–nucleus Drell–Yan data in global analysis of nuclear parton distribution functions
Paakkinen, Petja; Eskola, Kari; Paukkunen, Hannu (Elsevier B.V., 2017)Despite the success of modern nuclear parton distribution functions (nPDFs) in describing nuclear hard-process data, they still suffer from large uncertainties. One of the poorly constrained features is the possible asymmetry ... -
Double D-meson production in proton-proton and proton-lead collisions at the LHC
Helenius, Ilkka; Paukkunen, Hannu (Elsevier BV, 2020)We consider the simultaneous production of two heavy-flavoured hadrons – particularly D mesons – at the LHC. We base our calculations on collinearly factorized QCD at next-to-leading order, using the contemporary parton ... -
Pseudorapidity and transverse-momentum distributions of charged particles in proton–proton collisions at √s = 13 TeV
ALICE Collaboration; Chang, BeomSu; Kim, Dong Jo; Rak, Jan; Räsänen, Sami; Slupecki, Maciej; Snellman, Tomas; Trzaska, Wladyslaw; Vargyas, Márton; Viinikainen, Jussi (Elsevier B.V., 2016)The pseudorapidity (η) and transverse-momentum (pT) distributions of charged particles produced in proton–proton collisions are measured at the centre-of-mass energy √s = 13 TeV. The pseudorapidity distribution in |η| < ...