Compact Muon Solenoid
LHC, CERN
Visit us: CMS Public Website, CMS Physics ;
Contact us: CMS Publications Committee
| CMS-PAS-SMP-17-014 | ||
| Measurement of associated production of W bosons with charm quarks in proton-proton collisions at $\sqrt{s}= $ 13 TeV with the CMS experiment at the LHC | ||
| CMS Collaboration | ||
| April 2018 | ||
| Abstract: Measurements are presented of the associated production of a W boson and a charm quark (W+c) in proton-proton collisions at a center-of-mass energy of 13 TeV. The data correspond to an integrated luminosity of 35.7 fb$^{-1}$, collected by the CMS experiment at the LHC. The W bosons are identified by their decays into a muon and a neutrino. The charm quarks are tagged through the full reconstruction of $\mathrm{D}^*(2010)^{\pm}$ mesons in their decays $\mathrm{D}^*(2010)^{\pm} \to \mathrm{D}^0 + \pi^{\pm}_{\text{slow}} \to \mathrm{K}^{\mp} + \pi^{\pm} + \pi^{\pm}_{\text{slow}}$. The measurements are performed for the transverse momentum of the muon from the W boson decay greater than 26 GeV in the pseudorapidity range $|\eta^{\mu}| < $ 2.4 and for transverse momentum of the charm quark greater than 5 GeV. The total cross section of $\sigma(\mathrm{W+c}) = $ 1026 $\pm$ 31 (stat) $^{+76}_{-72}$ (syst) pb is obtained. The cross sectionW+c is also measured differentially with respect to the absolute value of the pseudorapidity of the muon from the W boson decay. Results are compared with theoretical predictions and are used to probe the strange quark content of the proton. | ||
|
Links:
CDS record (PDF) ;
inSPIRE record ;
CADI line (restricted) ;
These preliminary results are superseded in this paper, EPJC 79 (2019) 269. The superseded preliminary plots can be found here. |
||
| Figures | |
png pdf |
Figure 1:
Dominant contributions to W+c production at the LHC at leading order QCD. |
png |
Figure 1-a:
Dominant contribution to W+c production at the LHC at leading order QCD. |
png |
Figure 1-b:
Dominant contribution to W+c production at the LHC at leading order QCD. |
png pdf |
Figure 2:
Distribution of the muon transverse momentum (left) and muon pseudorapidity (right). The data (filled circles) are compared to the MC simulation of contributions of different processes (filled bands of different color). |
png pdf |
Figure 2-a:
Distribution of the muon transverse momentum. The data (filled circles) are compared to the MC simulation of contributions of different processes (filled bands of different color). |
png pdf |
Figure 2-b:
Distribution of the muon pseudorapidity. The data (filled circles) are compared to the MC simulation of contributions of different processes (filled bands of different color). |
png pdf |
Figure 3:
Distributions of missing transverse momentum (left) and of transverse mass (right). The data (filled circles) are compared to the MC simulation of contributions of different processes (filled bands of different color). |
png pdf |
Figure 3-a:
Distribution of missing transverse momentum. The data (filled circles) are compared to the MC simulation of contributions of different processes (filled bands of different color). |
png pdf |
Figure 3-b:
Distribution of transverse mass. The data (filled circles) are compared to the MC simulation of contributions of different processes (filled bands of different color). |
png pdf |
Figure 4:
Distributions of the reconstructed invariant mass of $ {\mathrm {K}}^\pm \pi ^\mp $ candidates (left) in the range $| \Delta m(\mathrm{D}^*,\,\mathrm{D}^0) -145.45| < $ 1 MeV, and of the reconstructed mass difference $\Delta m(\mathrm{D}^*,\,\mathrm{D}^0)$ (right). The SS combinations are subtracted. The data (closed symbols) are compared to MC simulation with contributions from different processes shown as histograms of different shades. |
png pdf |
Figure 4-a:
Distribution of the reconstructed invariant mass of $ {\mathrm {K}}^\pm \pi ^\mp $ candidates in the range $| \Delta m(\mathrm{D}^*,\,\mathrm{D}^0) -145.45| < $ 1 MeV. The SS combinations are subtracted. The data (closed symbols) are compared to MC simulation with contributions from different processes shown as histograms of different shades. |
png pdf |
Figure 4-b:
Distribution of the reconstructed mass difference $\Delta m(\mathrm{D}^*,\,\mathrm{D}^0)$. The SS combinations are subtracted. The data (closed symbols) are compared to MC simulation with contributions from different processes shown as histograms of different shades. |
png pdf |
Figure 5:
Number of events after OS-SS subtraction for the data (closed symbols) and MC simulation (filled histograms) as a function of $|\eta ^{{{\mu}}}|$. |
png pdf |
Figure 6:
Inclusive cross section of $\sigma ( {\mathrm {W}}+ {\mathrm {c}})$ (left) and the cross section ratio for $\sigma ( {\mathrm {W^+}}+ {\overline {\mathrm {c}}})/\sigma ( {\mathrm {W^-}}+ {\mathrm {c}})$ (right) at 13 TeV. The data are represented by a line with the statistical (total) uncertainty shown by a light (dark) shaded band. The measurements are compared to the NLO QCD prediction using several PDF sets, represented by symbols of different types. The horizontal error bars depict the total theory uncertainty, including the PDF and the scale variation uncertainty. |
png pdf |
Figure 6-a:
Inclusive cross section of $\sigma ( {\mathrm {W}}+ {\mathrm {c}})$ at 13 TeV. The data are represented by a line with the statistical (total) uncertainty shown by a light (dark) shaded band. The measurements are compared to the NLO QCD prediction using several PDF sets, represented by symbols of different types. The horizontal error bars depict the total theory uncertainty, including the PDF and the scale variation uncertainty. |
png pdf |
Figure 6-b:
Cross section ratio for $\sigma ( {\mathrm {W^+}}+ {\overline {\mathrm {c}}})/\sigma ( {\mathrm {W^-}}+ {\mathrm {c}})$ at 13 TeV. The data are represented by a line with the statistical (total) uncertainty shown by a light (dark) shaded band. The measurements are compared to the NLO QCD prediction using several PDF sets, represented by symbols of different types. The horizontal error bars depict the total theory uncertainty, including the PDF and the scale variation uncertainty. |
png pdf |
Figure 7:
Left: cross sections of $\sigma ( {\mathrm {W}}+ {\mathrm {c}})$ production at 13 TeV measured as a function of the pseudorapidity of the muon from the W boson decay. The data are presented by filled circles with the statistical (total) uncertainties shown by light (dark) shaded bands. The measurements are compared to the QCD predictions calculated with MCFM at NLO using different PDF sets, presented by symbols of different style. The horizontal error bars represent theory uncertainties including PDF uncertainty and the scale variation uncertainty. Right: $\sigma (\mathrm{W + D^*})$ production cross sections presented as a function of the pseudorapidity of the muon from the W boson decay. The data (closed symbols) are shown with their total (vertical error bars) and statistical uncertainties (inner error bars) and are compared to the predictions of the signal MC accounting for PDF uncertainties and scale variations, which are added in quadrature (shaded band). |
png pdf |
Figure 7-a:
Cross sections of $\sigma ( {\mathrm {W}} + {\mathrm {c}})$ production at 13 TeV measured as a function of the pseudorapidity of the muon from the W boson decay. The data are presented by filled circles with the statistical (total) uncertainties shown by light (dark) shaded bands. The measurements are compared to the QCD predictions calculated with MCFM at NLO using different PDF sets, presented by symbols of different style. The horizontal error bars represent theory uncertainties including PDF uncertainty and the scale variation uncertainty. |
png pdf |
Figure 7-b:
$\sigma (\mathrm{W + D^*})$ production cross sections presented as a function of the pseudorapidity of the muon from the W boson decay. The data (closed symbols) are shown with their total (vertical error bars) and statistical uncertainties (inner error bars) and are compared to the predictions of the signal MC accounting for PDF uncertainties and scale variations, which are added in quadrature (shaded band). |
png pdf |
Figure 7-c:
Cross sections of $\sigma ( {\mathrm {W}}^{+} + \overline{\mathrm {c}})$ production at 13 TeV measured as a function of the pseudorapidity of the muon from the W boson decay. The data are presented by filled circles with the statistical (total) uncertainties shown by light (dark) shaded bands. The measurements are compared to the QCD predictions calculated with MCFM at NLO using different PDF sets, presented by symbols of different style. The horizontal error bars represent theory uncertainties including PDF uncertainty and the scale variation uncertainty. |
png pdf |
Figure 7-d:
$\sigma (\mathrm{W^{+} + D^{*-}})$ production cross sections presented as a function of the pseudorapidity of the muon from the W boson decay. The data (closed symbols) are shown with their total (vertical error bars) and statistical uncertainties (inner error bars) and are compared to the predictions of the signal MC accounting for PDF uncertainties and scale variations, which are added in quadrature (shaded band). |
png pdf |
Figure 7-e:
Cross sections of $\sigma ( {\mathrm {W}}^{-} + {\mathrm {c}})$ production at 13 TeV measured as a function of the pseudorapidity of the muon from the W boson decay. The data are presented by filled circles with the statistical (total) uncertainties shown by light (dark) shaded bands. The measurements are compared to the QCD predictions calculated with MCFM at NLO using different PDF sets, presented by symbols of different style. The horizontal error bars represent theory uncertainties including PDF uncertainty and the scale variation uncertainty. |
png pdf |
Figure 7-f:
$\sigma (\mathrm{W^{-} + D^{*+}})$ production cross sections presented as a function of the pseudorapidity of the muon from the W boson decay. The data (closed symbols) are shown with their total (vertical error bars) and statistical uncertainties (inner error bars) and are compared to the predictions of the signal MC accounting for PDF uncertainties and scale variations, which are added in quadrature (shaded band). |
png pdf |
Figure 8:
The s quark distribution (upper) and the strangeness suppression factor (lower) as functions of $x$ at the factorization scale of 1.9 GeV$^2$ (left) and $m^2_{{\mathrm {W}}}$ (right). The results of the current analysis are presented with the fit uncertainties estimated by Hessian method (hatched band) and using MC replicas (shaded band). |
png pdf |
Figure 8-a:
The s quark distribution as a function of $x$ at the factorization scale of 1.9 GeV$^2$. The results of the current analysis are presented with the fit uncertainties estimated by Hessian method (hatched band) and using MC replicas (shaded band). |
png pdf |
Figure 8-b:
The s quark distribution as a function of $m^2_{{\mathrm {W}}}$. The results of the current analysis are presented with the fit uncertainties estimated by Hessian method (hatched band) and using MC replicas (shaded band). |
png pdf |
Figure 8-c:
The strangeness suppression factor as a function of $x$ at the factorization scale of 1.9 GeV$^2$. The results of the current analysis are presented with the fit uncertainties estimated by Hessian method (hatched band) and using MC replicas (shaded band). |
png pdf |
Figure 8-d:
The strangeness suppression factor as a function of $m^2_{{\mathrm {W}}}$. The results of the current analysis are presented with the fit uncertainties estimated by Hessian method (hatched band) and using MC replicas (shaded band). |
png pdf |
Figure 9:
The strangeness suppression factor as a function of $x$ at the factorization scale of 1.9 GeV$^2$ (left) and $m^2_{{\mathrm {W}}}$ (right). The results of the current analysis (hatched band) are compared to ABMP16nlo (dark shaded band) and ATLASepWZ16nnlo (light shaded band) PDFs. |
png pdf |
Figure 9-a:
The strangeness suppression factor as a function of $x$ at the factorization scale of 1.9 GeV$^2$. The results of the current analysis (hatched band) are compared to ABMP16nlo (dark shaded band) and ATLASepWZ16nnlo (light shaded band) PDFs. |
png pdf |
Figure 9-b:
The strangeness suppression factor as a function of $m^2_{{\mathrm {W}}}$. The results of the current analysis (hatched band) are compared to ABMP16nlo (dark shaded band) and ATLASepWZ16nnlo (light shaded band) PDFs. |
png pdf |
Figure 10:
The distributions of s quark (upper panel) in the proton and its relative uncertainty (lower panel) as functions of $x$ at the factorization scale of 1.9 GeV$^2$ (left) and $m^2_{{\mathrm {W}}}$ (right). The result of the current analysis (filled band) is compared to the result of Ref. [11] (dashed band). The PDF uncertainties resulting from the fit are shown. |
png pdf |
Figure 10-a:
The distributions of s quark (upper panel) in the proton and its relative uncertainty (lower panel) as a function of $x$ at the factorization scale of 1.9 GeV$^2$. The result of the current analysis (filled band) is compared to the result of Ref. [11] (dashed band). The PDF uncertainties resulting from the fit are shown. |
png pdf |
Figure 10-b:
The distributions of s quark (upper panel) in the proton and its relative uncertainty (lower panel) as a function of $m^2_{{\mathrm {W}}}$. The result of the current analysis (filled band) is compared to the result of Ref. [11] (dashed band). The PDF uncertainties resulting from the fit are shown. |
| Tables | |
png pdf |
Table 1:
Systematic uncertainties of the inclusive cross section and the five bins of $\eta ^{{{\mu}}}$ of the differential cross section of W+c in the fiducial range of the analysis. All contributions are in percent. The contributions listed above the gap cancel in the ratio $\sigma ( {\mathrm {W^+}}+ {\overline {\mathrm {c}}}) / \sigma ( {\mathrm {W^-}}+ {\mathrm {c}})$. |
png pdf |
Table 2:
Inclusive cross sections of W+c and W+$\mathrm{D}^*$ production at ${\sqrt {s}}=$ 13 TeV in the fiducial range of the analysis. |
png pdf |
Table 3:
Number of signal events, correction factors c and of the differential cross-sections in each $|\eta ^{{{\mu}}}|$ range for W+c (upper), $ {\mathrm {W^+}}+ {\overline {\mathrm {c}}}$ (middle) and $ {\mathrm {W^-}}+ {\mathrm {c}}$ (lower). |
png pdf |
Table 4:
NLO predictions for $\sigma ( {\mathrm {W}}+ {\mathrm {c}})$. The uncertainties account for PDF and scale variations. |
png pdf |
Table 5:
Theoretical predictions for $\mathrm{d}\sigma ( {\mathrm {W}}+ {\mathrm {c}})/\mathrm{d} |\eta ^\mu |$ calculated with MCFM at NLO for different PDF sets, used. The relative uncertainty due to PDF and scale variations are indicated. |
png pdf |
Table 6:
The partial $\chi ^2$ per number of data points, $n_{\text{dp}}$, and the global $\chi ^2$ per number of degree of freedom, $n_{\text{dof}}$, resulting from the PDF fit. |
| Summary |
|
The associated production of W bosons with charm quarks in pp collisions at ${\sqrt{s}}$ = 13 TeV is measured using the data collected by the CMS experiment in 2016 and corresponding to an integrated luminosity of $\mathcal{L}_{int}$ = 35.7 fb$^{-1}$. The W boson is detected through the presence of a high-$p_{\mathrm{T}}$ muon and missing transverse momentum. The charm quark is identified through the full reconstruction of ${{\mathrm{D}^{*}(2010)^{\pm}}}$ mesons, in decays ${{\mathrm{D}^{*}(2010)^{\pm}}} \to {\mathrm{D^0}} + \pi^{\pm}_{\text{slow}} \to \mathrm{K}^{\mp} + \pi^{\pm} + \pi^{\pm}_{\text{slow}}$. Since W+c is produced with the W boson and the charm quark of opposite charges, contributions from background processes, mainly c quark production from gluon splitting, are largely removed by subtracting the events in which the charges of the W boson and of the ${{\mathrm{D}^{*}(2010)^{\pm}}}$ meson have the same sign. The cross sections are measured in the kinematic range $|p_{\mathrm{T}}^{\mu}| > $ 26 GeV, $|\eta^{\mu}| < $ 2.4 and $p_{\mathrm{T}}^{\mathrm{c}} > $ 5 GeV, inclusively and in five bins of the absolute pseudorapidity of the muon coming from the W boson decay. The values for the inclusive cross section and for the cross section ratio are obtained as |
| References | ||||
| 1 | ATLAS Collaboration | Measurement of the $ W $-boson mass in pp collisions at $ \sqrt{s}= $ 7 TeV with the ATLAS detector | EPJC 78 (2018) 110 | 1701.07240 |
| 2 | NuTeV Collaboration | Precise measurement of dimuon production cross-sections in muon neutrino Fe and muon anti-neutrino Fe deep inelastic scattering at the Tevatron | PRD 64 (2001) 112006 | hep-ex/0102049 |
| 3 | CCFR Collaboration | Determination of the strange quark content of the nucleon from a next-to-leading order QCD analysis of neutrino charm production | Z. Phys. C 65 (1995) 189 | hep-ex/9406007 |
| 4 | NOMAD Collaboration | A Precision Measurement of Charm Dimuon Production in Neutrino Interactions from the NOMAD Experiment | NPB 876 (2013) 339 | 1308.4750 |
| 5 | A. Kayis-Topaksu et al. | Measurement of charm production in neutrino charged-current interactions | New J. Phys. 13 (2011) 093002 | 1107.0613 |
| 6 | ATLAS Collaboration | Determination of the strange quark density of the proton from ATLAS measurements of the $ W \to \ell \nu $ and $ Z \to \ell\ell $ cross sections | PRL 109 (2012) 012001 | 1203.4051 |
| 7 | CDF Collaboration | First measurement of the production of a $ W $ boson in association with a single charm quark in $ p \bar{p} $ collisions at $ \sqrt{s} = $ 1.96-TeV | PRL 100 (2008) 091803 | 0711.2901 |
| 8 | CDF Collaboration | Observation of the Production of a W Boson in Association with a Single Charm Quark | PRL 110 (2013) 071801 | 1209.1921 |
| 9 | D0 Collaboration | Measurement of the ratio of the $ p \bar{p} \to W^+ c^- $ jet cross section to the inclusive $ p \bar{p} \to W + $ jets cross section | PLB 666 (2008) 23 | 0803.2259 |
| 10 | CMS Collaboration | Measurement of associated W + charm production in pp collisions at $ \sqrt{s} = $ 7 TeV | JHEP 02 (2014) 013 | CMS-SMP-12-002 1310.1138 |
| 11 | CMS Collaboration | Measurement of the muon charge asymmetry in inclusive $ pp \to W+X $ production at $ \sqrt s = $ 7 TeV and an improved determination of light parton distribution functions | PRD 90 (2014) 032004 | CMS-SMP-12-021 1312.6283 |
| 12 | ATLAS Collaboration | Measurement of the production of a $ W $ boson in association with a charm quark in $ pp $ collisions at $ \sqrt{s} = $ 7 TeV with the ATLAS detector | JHEP 05 (2014) 068 | 1402.6263 |
| 13 | S. Alekhin et al. | Determination of Strange Sea Quark Distributions from Fixed-target and Collider Data | PRD 91 (2015) 094002 | 1404.6469 |
| 14 | ATLAS Collaboration | Precision measurement and interpretation of inclusive $ W^+ $ , $ W^- $ and $ Z/\gamma ^* $ production cross sections with the ATLAS detector | EPJC 77 (2017) 367 | 1612.03016 |
| 15 | S. Alekhin, J. Blumlein, and S. Moch | Strange sea determination from collider data | PLB 777 (2018) 134 | 1708.01067 |
| 16 | J. M. Campbell and R. K. Ellis | An Update on vector boson pair production at hadron colliders | PRD 60 (1999) 113006 | hep-ph/9905386 |
| 17 | J. M. Campbell and R. K. Ellis | MCFM for the Tevatron and the LHC | NPPS 205-206 (2010) 10 | 1007.3492 |
| 18 | J. M. Campbell and R. K. Ellis | Top-Quark Processes at NLO in Production and Decay | JPG 42 (2015) 015005 | 1204.1513 |
| 19 | CMS Collaboration | Description and performance of track and primary-vertex reconstruction with the CMS tracker | JINST 9 (2014) P10009 | CMS-TRK-11-001 1405.6569 |
| 20 | CMS Collaboration | Performance of CMS muon reconstruction in $ pp $ collision events at $ \sqrt{s}= $ 7 TeV | JINST 7 (2012) P10002 | CMS-MUO-10-004 1206.4071 |
| 21 | CMS Collaboration | The CMS experiment at the CERN LHC | JINST 3 (2008) S08004 | CMS-00-001 |
| 22 | CMS Collaboration | Particle-flow reconstruction and global event description with the CMS detector | JINST 12 (2017) P10003 | CMS-PRF-14-001 1706.04965 |
| 23 | W. Adam, B. Mangano, T. Speer, and T. Todorov | Track Reconstruction in the CMS tracker | CMS-NOTE-2006-041 | |
| 24 | S. Agostinelli et al. | Geant4 - a simulation toolkit | Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 506 (2003) 250 | |
| 25 | J. Alwall et al. | The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations | JHEP 07 (2014) 079 | 1405.0301 |
| 26 | T. Sjostrand, S. Mrenna, and P. Z. Skands | A Brief Introduction to PYTHIA 8.1 | CPC 178 (2008) 852 | 0710.3820 |
| 27 | NNPDF Collaboration | Parton distributions for the LHC Run II | JHEP 04 (2015) 040 | 1410.8849 |
| 28 | J. M. Campbell, R. K. Ellis, P. Nason, and E. Re | Top-Pair Production and Decay at NLO Matched with Parton Showers | JHEP 04 (2015) 114 | 1412.1828 |
| 29 | R. Frederix, E. Re, and P. Torrielli | Single-top t-channel hadroproduction in the four-flavour scheme with POWHEG and aMC@NLO | JHEP 09 (2012) 130 | 1207.5391 |
| 30 | E. Re | Single-top Wt-channel production matched with parton showers using the POWHEG method | EPJC 71 (2011) 1547 | 1009.2450 |
| 31 | S. Alioli, P. Nason, C. Oleari, and E. Re | NLO single-top production matched with shower in POWHEG: s- and t-channel contributions | JHEP 09 (2009) 111 | 0907.4076 |
| 32 | CMS Collaboration | Event generator tunes obtained from underlying event and multiparton scattering measurements | EPJC 76 (2016) 155 | CMS-GEN-14-001 1512.00815 |
| 33 | CMS Collaboration | Investigations of the impact of the parton shower tuning in Pythia 8 in the modelling of $ \mathrm{t\overline{t}} $ at $ \sqrt{s}= $ 8 and 13 TeV | CMS-PAS-TOP-16-021 | CMS-PAS-TOP-16-021 |
| 34 | CMS Collaboration | Performance of muon identification in pp collisions at $ sqrt{s} = $ 7 TeV | CMS-PAS-MUO-10-002 | |
| 35 | CMS Collaboration | Performance of missing energy reconstruction in 13 TeV pp collision data using the CMS detector | CMS-PAS-JME-16-004 | CMS-PAS-JME-16-004 |
| 36 | Particle Data Group Collaboration | Review of Particle Physics | CPC 40 (2016) 100001 | |
| 37 | R. Fruhwirth, W. Waltenberger, and P. Vanlaer | Adaptive Vertex Fitting | CMS-NOTE-2007-008 | |
| 38 | G. J. Feldman et al. | Observation of the Decay $ D{^*+} \to D^0 \pi^+ $ | PRL 38 (1977) 1313 | |
| 39 | M. Lisovyi, A. Verbytskyi, and O. Zenaiev | Combined analysis of charm-quark fragmentation-fraction measurements | EPJC 76 (2016) 397 | 1509.01061 |
| 40 | CMS Collaboration | CMS Luminosity Measurements for the 2016 Data Taking Period | CMS-PAS-LUM-17-001 | CMS-PAS-LUM-17-001 |
| 41 | CMS Collaboration | Measurement of Tracking Efficiency | CMS-PAS-TRK-10-002 | |
| 42 | J. E. Gaiser | Ph.d. thesis | Stanford University 15 (1982)438 | |
| 43 | S. Alekhin, J. Blumlein, and S. Moch | NLO PDFs from the ABMP16 fit | 1803.07537 | |
| 44 | S. Dulat et al. | New parton distribution functions from a global analysis of quantum chromodynamics | PRD 93 (2016) 033006 | 1506.07443 |
| 45 | L. A. Harland-Lang, A. D. Martin, P. Motylinski, and R. S. Thorne | Parton distributions in the LHC era: MMHT 2014 PDFs | EPJC 75 (2015) 204 | 1412.3989 |
| 46 | NNPDF Collaboration | Parton distributions from high-precision collider data | EPJC 77 (2017) 663 | 1706.00428 |
| 47 | E. L. Berger, F. Halzen, C. S. Kim, and S. Willenbrock | Weak-boson production at fermilab tevatron energies | PRD 40 (1989) 83 | |
| 48 | U. Baur et al. | The charm content of W + 1 jet events as a probe of the strange quark distribution function | PLB 318 (1993) 544 | hep-ph/9308370 |
| 49 | H.-L. Lai et al. | The strange parton distribution of the nucleon: global analysis and applications | JHEP 04 (2007) 089 | hep-ph/0702268 |
| 50 | H1 and ZEUS Collaborations | Combined measurement and QCD analysis of the inclusive $ \mathrm{e}^\pm {\mathrm{p}} $ scattering cross sections at HERA | JHEP 01 (2010) 109 | 0911.0884 |
| 51 | H1 and ZEUS Collaborations | Combination of measurements of inclusive deep inelastic $ {\mathrm{e}^{\pm}{\mathrm{p}}} $ scattering cross sections and QCD analysis of HERA data | EPJC 75 (2015) 580 | 1506.06042 |
| 52 | CMS Collaboration | Measurement of the differential cross section and charge asymmetry for inclusive $ \mathrm {p}\mathrm {p}\rightarrow \mathrm {W}^{\pm}+X $ production at $ {\sqrt{s}} = $ 8 TeV | EPJC 76 (2016) 469 | CMS-SMP-14-022 1603.01803 |
| 53 | T. Carli et al. | A posteriori inclusion of parton density functions in NLO QCD final-state calculations at hadron colliders: the APPLGRID project | EPJC 66 (2010) 503 | 0911.2985 |
| 54 | S. Alekhin et al. | HERAFitter | EPJC 75 (2015) 304 | 1410.4412 |
| 55 | HERAFitter Group | HERAFitter web site | link | |
| 56 | V. N. Gribov and L. N. Lipatov | Deep inelastic $ \mathrm{e} $-$ {\mathrm{p}} $ scattering in perturbation theory | Sov. J. NP 15 (1972)438 | |
| 57 | G. Altarelli and G. Parisi | Asymptotic freedom in parton language | NPB 126 (1977) 298 | |
| 58 | G. Curci, W. Furmanski, and R. Petronzio | Evolution of parton densities beyond leading order: The non-singlet case | NPB 175 (1980) 27 | |
| 59 | W. Furmanski and R. Petronzio | Singlet parton densities beyond leading order | PLB 97 (1980) 437 | |
| 60 | S. Moch, J. A. M. Vermaseren, and A. Vogt | The three-loop splitting functions in QCD: the non-singlet case | NPB 688 (2004) 101 | hep-ph/0403192 |
| 61 | A. Vogt, S. Moch, and J. A. M. Vermaseren | The three-loop splitting functions in QCD: the singlet case | NPB 691 (2004) 129 | hep-ph/0404111 |
| 62 | M. Botje | QCDNUM: fast QCD evolution and convolution | CPC 182 (2011) 490 | 1005.1481 |
| 63 | R. S. Thorne | Variable-flavor number scheme for NNLO | PRD 73 (2006) 054019 | hep-ph/0601245 |
| 64 | A. D. Martin, W. J. Stirling, R. S. Thorne, and G. Watt | Parton distributions for the LHC | EPJC 63 (2009) 189 | 0901.0002 |
| 65 | J. Pumplin et al. | Uncertainties of predictions from parton distribution functions. II. The Hessian method | PRD 65 (2001) 014013 | hep-ph/0101032 |
| 66 | W. T. Giele and S. Keller | Implications of hadron collider observables on parton distribution function uncertainties | PRD 58 (1998) 094023 | hep-ph/9803393 |
| 67 | W. T. Giele, S. A. Keller, and D. A. Kosower | Parton distribution function uncertainties | hep-ph/0104052 | |
|
|
Compact Muon Solenoid LHC, CERN |
|
|
|
|
|
|