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| CMS-PAS-SMP-17-009 | ||
| Azimuthal angular correlations in high transverse momentum dijet events at 13 TeV | ||
| CMS Collaboration | ||
| September 2017 | ||
| Abstract: The azimuthal angle correlation between the two jets with the largest transverse momenta in inclusive 2-jet topologies, close to the back-to-back configuration, is measured for several regions of the leading jet transverse momentum. Measurements of the same observable requiring the presence of extra jets are also presented. The analysis is based on proton-proton collision data collected with the CMS experiment at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 35.9 fb$^{-1}$. The results are compared to predictions using Monte Carlo event generators which combine perturbative QCD calculations up to next-to-leading-order accuracy with contributions from parton showers, hadronization, and multiparton interactions. | ||
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Links:
CDS record (PDF) ;
CADI line (restricted) ;
These preliminary results are superseded in this paper, EPJC 79 (2019) 773. The superseded preliminary plots can be found here. |
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| Figures | |
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Figure 1:
Normalized inclusive 2-jet distributions as a function of the azimuthal difference of the two leading jets $ {\Delta \phi _\text {1,2}} $ for nine $ {{p_{\mathrm {T}}} ^{\text {max}}} $ regions, scaled by multiplicative factors for presentation purposes. The error bars on the data points include statistical and systematic uncertainties. Overlaid on the data are predictions from the PH-2J+PYTHIA8 event generator. |
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Figure 2:
Ratios of PYTHIA8, HERWIG++, and MadGraph+PYTHIA8 predictions to data, of the normalized inclusive 2-jet distributions as a function of the azimuthal difference of the two leading jets $ {\Delta \phi _\text {1,2}} $, for all $ {{p_{\mathrm {T}}} ^{\text {max}}} $ regions. The solid band indicates the total experimental uncertainty and the error bars on the MC points represent the statistical uncertainties of the simulated data. |
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Figure 3:
Ratios of PH-2J+PYTHIA8, PH-3J+PYTHIA8 and MadGraph+PYTHIA8 predictions to data, of the normalized inclusive 2-jet distributions as a function of the azimuthal difference of the two leading jets $ {\Delta \phi _\text {1,2}} $, for all $ {{p_{\mathrm {T}}} ^{\text {max}}} $ regions. The solid band indicates the total experimental uncertainty and the error bars on the MC points represent the statistical uncertainties of the simulated data. |
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Figure 4:
Normalized inclusive 3-jet distributions as a function of the azimuthal difference of the two leading jets $ {\Delta \phi _\text {1,2}} $ for nine $ {{p_{\mathrm {T}}} ^{\text {max}}} $ regions, scaled by multiplicative factors for presentation purposes. The error bars on the data points include statistical and systematic uncertainties. Overlaid on the data are predictions from the PH-2J+PYTHIA8 event generator. |
png pdf |
Figure 5:
Ratios of PYTHIA8, HERWIG++, and MadGraph+PYTHIA8 predictions to data, of the normalized inclusive 3-jet distributions as a function of the azimuthal difference of the two leading jets $ {\Delta \phi _\text {1,2}} $, for all $ {{p_{\mathrm {T}}} ^{\text {max}}} $ regions. The solid band indicates the total experimental uncertainty and the error bars on the MC points represent the statistical uncertainties of the simulated data. |
png pdf |
Figure 6:
Ratios of PH-2J+PYTHIA8, PH-3J+PYTHIA8 and MadGraph+PYTHIA8 predictions to data, of the normalized inclusive 3-jet distributions as a function of the azimuthal difference of the two leading jets $ {\Delta \phi _\text {1,2}} $, for all $ {{p_{\mathrm {T}}} ^{\text {max}}} $ regions. The solid band indicates the total experimental uncertainty and the error bars on the MC points represent the statistical uncertainties of the simulated data. |
| Tables | |
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Table 1:
Trigger used according to the various $ {{p_{\mathrm {T}}} ^{\text {max}}} $ regions. |
| Summary |
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Measurements of the normalized inclusive 2-jet and 3-jet distributions as a function of $ {\Delta\phi_\text{1,2}} $ are presented for several regions in the leading-jet transverse momentum $ {p_{\mathrm{T}}}^{\text{max}} $. The measurements are performed using data collected with the CMS experiment at the CERN LHC, corresponding to an integrated luminosity of 35.9 fb$^{-1}$ of proton-proton collisions at $\sqrt{\smash[b]{s}} = $ 13 TeV. The measured distributions $ {\Delta\phi_\text{1,2}} $ are compared to predictions from PYTHIA8, HERWIG++, MadGraph+PYTHIA8 and POWHEG (PH-2J and PH-3J) matched to PYTHIA8. The tree-level multijet event generator MadGraph in combination with PYTHIA8 for showering, hadronization, and multiparton interactions, shows deviations from the measured $ {\Delta\phi_\text{1,2}} $ for the inclusive2-jet case, and even larger deviations for the 3-jet case. The PYTHIA8 and HERWIG++ predictions show large deviations (up to 10%) for the 2-jet inclusive cross sections whereas their predictions are in reasonable agreement with the inclusive 3-jet distributions. The NLO predictions of PH-2J for the inclusive 2-jet case are similar to those from PYTHIA8 and HERWIG++ for high $ {p_{\mathrm{T}}}^{\text{max}} $ slices, except for the $ {\Delta\phi_\text{1,2}} $ region close to 180$^\circ$, the PH-3J predictions agree with the measurements. For the inclusive 3-jet case, PH-2J performs similar to PYTHIA8 and HERWIG++ in the whole range for high $ {p_{\mathrm{T}}}^{\text{max}} $ slices, PH-3J shows deviations from the measurements. The measurement of the back-to-back region of dijet correlations are a very sensitive probe to the treatment of soft parton radiation in addition to the hard dijet system, and theoretical predictions show deviations up to 10% mainly in the $ {\Delta\phi_\text{1,2}} $ region close to 180$^\circ$. |
| References | ||||
| 1 | S. Catani, M. Grazzini, and H. Sargsyan | Azimuthal asymmetries in QCD hard scattering: infrared safe but divergent | JHEP 06 (2017) 017 | |
| 2 | S. Catani, M. Grazzini, and A. Torre | Transverse-momentum resummation for heavy-quark hadroproduction | Nucl.Phys. B890 (2015) 518--538 | |
| 3 | D0 Collaboration | Measurement of dijet azimuthal decorrelations at central rapidities in $ \mathrm{p}\overline{\mathrm{p}} $ collisions at $ \sqrt{s}= $ 1.96 TeV | PRL 94 (2005) 221801 | hep-ex/0409040 |
| 4 | D0 Collaboration | Measurement of the combined rapidity and $ p_{T} $ dependence of dijet azimuthal decorrelations in $ \mathrm{p}\overline{\mathrm{p}} $ collisions at $ \sqrt{s}= $ 1.96 TeV | PLB 721 (2013) 212 | 1212.1842 |
| 5 | ATLAS Collaboration | Measurement of dijet azimuthal decorrelations in $ \mathrm{p}\mathrm{p} $ collisions at $ \sqrt{s}= $ 7 TeV | PRL 106 (2011) 172002 | 1102.2696 |
| 6 | CMS Collaboration | Dijet azimuthal decorrelations in $ \mathrm{p}\mathrm{p} $ collisions at $ \sqrt{s}= $ 7 TeV | PRL 106 (2011) 122003 | CMS-QCD-10-026 1101.5029 |
| 7 | CMS Collaboration | Measurement of dijet azimuthal decorrelation in pp collisions at $ \sqrt{s}= $ 8 TeV | EPJC 76 (2016) 536 | CMS-SMP-14-015 1602.04384 |
| 8 | CMS Collaboration | Measurements of inclusive 2-jet, 3-jet, and 4-jet azimuthal correlations in pp collisions $ \sqrt{s}= $ 13 TeV | CDS | |
| 9 | ATLAS Collaboration | Measurement of three-jet production cross-sections in $ pp $ collisions at 7 TeV centre-of-mass energy using the ATLAS detector | EPJC 75 (2015) 228 | 1411.1855 |
| 10 | ATLAS Collaboration | Measurement of four-jet differential cross sections in $ \sqrt{s}= $ 8 TeV proton-proton collisions using the ATLAS detector | JHEP 12 (2015) 105 | 1509.07335 |
| 11 | CMS Collaboration | The CMS experiment at the CERN LHC | JINST 03 (2008) S08004 | CMS-00-001 |
| 12 | M. Bahr et al. | Herwig++ physics and manual | EPJC 58 (2008) 639 | 0803.0883 |
| 13 | T. Sjostrand et al. | An introduction to PYTHIA 8.2 | CPC 191 (2015) 159 | 1410.3012 |
| 14 | B. Andersson | The Lund model | Camb. Monogr. Part. Phys. NP Cosmol. 7 (1997) 1 | |
| 15 | B. R. Webber | A QCD model for jet fragmentation including soft gluon interference | NPB 238 (1984) 492 | |
| 16 | CMS Collaboration | Event generator tunes obtained from underlying event and multiparton scattering measurements | EPJC 76 (2016) 155 | CMS-GEN-14-001 1512.00815 |
| 17 | NNPDF Collaboration | Parton distributions with QED corrections | NPB 877 (2013) 290 | 1308.0598 |
| 18 | NNPDF Collaboration | Unbiased global determination of parton distributions and their uncertainties at NNLO and at LO | NPB 855 (2012) 153 | 1107.2652 |
| 19 | J. Pumplin et al. | New generation of parton distributions with uncertainties from global QCD analysis | JHEP 07 (2002) 012 | hep-ph/0201195 |
| 20 | GEANT4 Collaboration | Geant4 -- a simulation tool kit | NIMA 506 (2003) 250 | |
| 21 | 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 |
| 22 | J. Alwall et al. | Comparative study of various algorithms for the merging of parton showers and matrix elements in hadronic collisions | EPJC53 (2008) 473--500 | 0706.2569 |
| 23 | S. Frixione, P. Nason, and C. Oleari | Matching NLO QCD computations with parton shower simulations: the POWHEG method | JHEP 11 (2007) 070 | 0709.2092 |
| 24 | S. Alioli, P. Nason, C. Oleari, and E. Re | A general framework for implementing NLO calculations in shower monte carlo programs: the POWHEG BOX | JHEP 06 (2010) 043 | 1002.2581 |
| 25 | P. Nason | A new method for combining NLO QCD with shower Monte Carlo algorithms | JHEP 11 (2004) 040 | hep-ph/0409146 |
| 26 | S. Alioli et al. | Jet pair production in POWHEG | JHEP 11 (2011) 081 | 1012.3380 |
| 27 | A. Kardos, P. Nason, and C. Oleari | Three-jet production in POWHEG | JHEP 04 (2014) 043 | 1402.4001 |
| 28 | K. Hamilton, P. Nason, C. Oleari, and G. Zanderighi | Merging H/W/Z + 0 and 1 jet at NLO with no merging scale: a path to parton shower + NNLO matching | JHEP 05 (2013) 082 | |
| 29 | K. Hamilton, P. Nason, and G. Zanderighi | MINLO: Multi-Scale Improved NLO | JHEP 10 (2012) 155 | |
| 30 | NNPDF Collaboration | Parton distributions for the LHC Run II | JHEP 04 (2015) 040 | 1410.8849 |
| 31 | CMS Collaboration | The CMS high level trigger | EPJC 46 (2006) 605 | hep-ex/0512077 |
| 32 | CMS Collaboration | Particle-flow reconstruction and global event description with the CMS detector | Submitted to \it JINST | CMS-PRF-14-001 1706.04965 |
| 33 | M. Cacciari, G. P. Salam, and G. Soyez | The anti-$ k_{\mathrm{t}} $ jet clustering algorithm | JHEP 04 (2008) 063 | 0802.1189 |
| 34 | M. Cacciari, G. P. Salam, and G. Soyez | FastJet user manual | EPJC 72 (2012) 1896 | 1111.6097 |
| 35 | CMS Collaboration | Jet energy scale and resolution in the CMS experiment in pp collisions at 8 TeV | CMS-JME-13-004 1607.03663 |
|
| 36 | G. D'Agostini | A multidimensional unfolding method based on bayes theorem | Nucl.Instrum.Meth. A362 (1995) 487 | |
| 37 | T. Adye | Unfolding algorithms and tests using RooUnfold | 1105.1160 | |
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