Parton distributions in the LHC era: MMHT 2014 PDFs

By L. Harland–Lang, Alan D. Martin, Patrick Motylinski, R. Thorne. European Physical Journal C: Particles and Fields, 2014

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We present LO, NLO and NNLO sets of parton distribution functions (PDFs) of the proton determined from global analyses of the available hard scattering data. These MMHT2014 PDFs supersede the ‘MSTW2008’ parton sets, but they are obtained within the same basic framework. We include a variety of new data sets, from the LHC, updated Tevatron data and the HERA combined H1 and ZEUS data on the total and charm structure functions. We also improve the theoretical framework of the previous analysis. These new PDFs are compared to the ‘MSTW2008’ parton sets. In most cases the PDFs, and the predictions, are within one standard deviation of those of MSTW2008. The major changes are the $$u-d$$u-d valence quark difference at small $$x$$x due to an improved parameterisation and, to a lesser extent, the strange quark PDF due to the effect of certain LHC data and a better treatment of the $$D \rightarrow \mu $$D→μ branching ratio. We compare our MMHT PDF sets with those of other collaborations; in particular with the NNPDF3.0 sets, which are contemporary with the present analysis.

Subfields: Artificial Intelligence, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/0c264b93d4774e85b2c7ecc4566a89f514861428

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Citations in the corpus

High precision determination of the gluon fusion Higgs boson cross-section at the LHC (2016, background): “16 we compare the 68% C.L. predictions from CT14, MMHT2014 and NNPDF3.”
Search for dark matter and other new phenomena in events with an energetic jet and large missing transverse momentum using the ATLAS detector (2017, methodology): “Uncertainties affecting the signal acceptance in the generation of signal samples in- clude: uncertainties in the modelling of the initial- and final-state gluon radiation, de- termined using simulated samples with modified parton-shower parameters (by factors of two or one half); uncertainties due ”
Physics case for an LHCb Upgrade II - Opportunities in flavour physics, and beyond, in the HL-LHC era (2018, methodology): “The LHCb vector-boson production measurements have been included within fits to data to determine PDFs [409–412].”
Les Houches 2017: Physics at TeV Colliders Standard Model Working Group Report (2017, methodology): “The PDF sets that have been used to tune the parton shower are MMHT2014lo68cl and MMHT2014nlo68cl [601].”
Les Houches 2015: Physics at TeV Colliders Standard Model Working Group Report (2016, methodology): “MMHT2014 NLO PDFs (and the NNLO version for the NNLO calculations) were to be used, with a central value of αs(mZ) = 0.118.”
The photon content of the proton (2017, methodology): “For example CT14nnlo and MMHT2014nnlo68cl have their b-quark threshold at 4.75 GeV, while NNPDF30 nnlo as 0118 has its threshold at 4.18 GeV, as can be seen in Fig.”
PDF4LHC recommendations for LHC Run II (2015, methodology): “The MMHT14 PDFs provide a much better description to the LHC W lepton asymmetry data [34,50] than its predecessor MSTW08, thanks to the various improvements already implemented in the MMSTWW (also known as MSTW08CPdeut) intermediate release.”
Higgs Physics at the HL-LHC and HE-LHC (2019, methodology): “The results have been obtained using the parton distribution functions PDF4LHC15_nlo_100_pdfas [112, 97, 98, 280], along with the corresponding value for ↵s for both the NLO and the LO calculation.”
Measurement of D-meson production at mid-rapidity in pp collisions at √s=7 TeV (2017, methodology): “The LOkT-factorisation calculations were performed with an update s t of unintegrated gluon-distribution functions computed from the recent MMH T2014-LO PDFs [50].”