Compact Muon Solenoid
LHC, CERN
Visit us: CMS Public Website, CMS Physics ;
Contact us: CMS Publications Committee
| CMS-PAS-SMP-19-002 | ||
| Measurement of the inclusive W$\gamma$ production cross section in proton-proton collisions at $\sqrt{s} = $ 13 TeV and constraints on effective field theory coefficients | ||
| CMS Collaboration | ||
| November 2020 | ||
| Abstract: The cross section of inclusive W$\gamma$ production in proton-proton collisions at a center-of-mass energy of 13 TeV has been measured based on 137.1 fb$^{-1}$ of data collected using the CMS experiment at the LHC. Both the electron and the muon decay modes of the W boson are considered by performing a maximum likelihood fit to the lepton-photon mass distribution. The measured cross section is compared to theoretical predictions made at next-to-leading order in quantum chromodynamics. In addition, 95% confidence level limits on anomalous triple gauge couplings are reported within the framework of effective field theory. | ||
|
Links:
CDS record (PDF) ;
CADI line (restricted) ;
These preliminary results are superseded in this paper, Accepted by PRL. The superseded preliminary plots can be found here. |
||
| Figures | |
png pdf |
Figure 1:
Representative Feynman diagram for ${\mathrm{p}} {\mathrm{p}} \to \ell ^+\nu _{\ell}\gamma $ production with a TGC vertex. |
png pdf |
Figure 2:
Distributions of the invariant mass of the lepton-photon system in the muon channel (left) and electron channel (right). The electron-induced photon estimate is scaled by a factor of 1.8 in the plot of $m_{\ell \gamma}$. The uncertainty in the expected yield is the sum of the systematic uncertainties added in quadrature. W$\gamma $ refers to the MadGraph-5_aMC@NLO simulation of W$\gamma $. |
png pdf |
Figure 2-a:
Distribution of the invariant mass of the lepton-photon system in the muon channel. The electron-induced photon estimate is scaled by a factor of 1.8 in the plot of $m_{\ell \gamma}$. The uncertainty in the expected yield is the sum of the systematic uncertainties added in quadrature. W$\gamma $ refers to the MadGraph-5_aMC@NLO simulation of W$\gamma $. |
png pdf |
Figure 2-b:
Distribution of the invariant mass of the lepton-photon system in the electron channel. The electron-induced photon estimate is scaled by a factor of 1.8 in the plot of $m_{\ell \gamma}$. The uncertainty in the expected yield is the sum of the systematic uncertainties added in quadrature. W$\gamma $ refers to the MadGraph-5_aMC@NLO simulation of W$\gamma $. |
png pdf |
Figure 3:
The photon $ {p_{\mathrm {T}}} $ distribution used for the extraction of limits on dimension-six EFT operators. The last bin includes overflow. |
| Tables | |
png pdf |
Table 1:
Expected and observed number of events. The electron-induced photon estimate is scaled by a factor of $1.8$. The uncertainty is the sum of the systematic uncertainties added in quadrature. W$\gamma $ refers to the MadGraph-5_aMC@NLO simulation of W$\gamma $. |
png pdf |
Table 2:
Observed and expected 95% confidence level limits on five dimension-six operator coefficients. The units of the limits are TeV$^{-2}$. |
| Summary |
| In conclusion, the inclusive cross section for $\mathrm{ pp \to W \gamma }$ production has been measured for the first time at a center-of-mass energy of 13 TeV and with a precision of 4.7%. The measured cross section is $\sigma = $ 15.58 $\pm$ 0.75 pb $=$ 15.58 $\pm$ 0.05 (stat) $\pm$ 0.73 (exp) $\pm$ 0.15 (theory) pb, which is consistent with the MadGraph-5_aMC@NLO in QCD prediction of $\sigma = $ 15.4 $\pm$ 1.2 (scale) $\pm$ 0.1 (PDF) pb and below the POWHEG NLO in QCD with NLO competition prediction of $\sigma = $ 22.4 $\pm$ 3.2 (scale) $\pm$ 0.1 (PDF) pb. The cross sections separately measured in the electron channel and the muon channel are consistent with each other. The high photon $p_{\mathrm{T}}$ part of the photon $p_{\mathrm{T}}$ distribution was used to set 95% confidence level limits on dimension-six EFT parameters, including the most stringent limit to date on the coefficient of the lowest dimension CP-even operator that directly alters the WW$\gamma$ TGC. |
| References | ||||
| 1 | Y. Cui, T. Gherghetta, and J. D. Wells | Emergent electroweak symmetry breaking with composite W, Z bosons | JHEP 11 (2009) 80 | 0907.0906 |
| 2 | C. Degrande et al. | Effective field theory: A modern approach to anomalous couplings | Annals of Physics 335 (2013) 21 | 1205.4231 |
| 3 | CMS Collaboration | Measurement of the W$\gamma $ and Z$\gamma $ inclusive cross sections in pp collisions at $ \sqrt{s} = $ 7 TeV and limits on anomalous triple gauge boson couplings | PRD 89 (2014) 092005 | CMS-EWK-11-009 1308.6832 |
| 4 | ATLAS Collaboration | Measurements of W$\gamma $ and Z$\gamma $ production in pp collisions at $ \sqrt{s} = $ 7 TeV with the ATLAS detector at the LHC | PRD 87 (2013) 112003 | 1205.2531 |
| 5 | CMS Collaboration | The CMS experiment at the CERN LHC | JINST 3 (2008) S08004 | CMS-00-001 |
| 6 | CMS Collaboration | Performance of electron reconstruction and selection with the CMS detector in proton-proton collisions at $ \sqrt{s} = $ 8 TeV | JINST 10 (2015) P06005 | CMS-EGM-13-001 1502.02701 |
| 7 | CMS Collaboration | Performance of photon reconstruction and identification with the CMS detector in proton-proton collisions at $ \sqrt{s} = $ 8 TeV | JINST 10 (2015) P08010 | CMS-EGM-14-001 1502.02702 |
| 8 | CMS Collaboration | Performance of the CMS muon detector and muon reconstruction with proton-proton collisions at $ \sqrt{s} = $ 13 TeV | JINST 13 (2018) P06015 | CMS-MUO-16-001 1804.04528 |
| 9 | CMS Collaboration | Particle-flow reconstruction and global event description with the CMS detector | JINST 12 (2017) P10003 | CMS-PRF-14-001 1706.04965 |
| 10 | CMS Collaboration | Performance of missing transverse momentum reconstruction in proton-proton collisions at $ \sqrt{s} = $ 13 TeV using the CMS detector | Journal of Instrumentation 14 (2019) P07004 | CMS-JME-17-001 1903.06078 |
| 11 | D. Bertolini, P. Harris, M. Low, and N. Tran | Pileup per particle identification | JHEP 10 (2014) 059 | 1407.6013 |
| 12 | M. Grazzini, S. Kallweit, and M. Wiesemann | Fully differential NNLO computations with MATRIX | The European Physical Journal C 78 (2018) 537 | 1711.06631 |
| 13 | M. Grazzini, S. Kallweit, and D. Rathlev | W$\gamma $ and Z$\gamma $ production at the LHC in NNLO QCD | JHEP 07 (2015) 085 | 1504.01330 |
| 14 | E. Accomando, A. Denner, and S. Pozzorini | Electroweak-correction effects in gauge-boson pair production at the CERN LHC | PRD 65 (2002) 073003 | hep-ph/0110114 |
| 15 | A. Denner, S. Dittmaier, M. Hecht, and C. Pasold | NLO QCD and electroweak corrections to W$ {+}\gamma $ production with leptonic W-boson decays | JHEP 04 (2015) 018 | 1412.7421 |
| 16 | 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 |
| 17 | R. Frederix and S. Frixione | Merging meets matching in MC@NLO | JHEP 12 (2012) 061 | 1209.6215 |
| 18 | P. Nason | A new method for combining NLO QCD with shower Monte Carlo algorithms | JHEP 11 (2004) 040 | hep-ph/0409146 |
| 19 | S. Frixione, P. Nason, and C. Oleari | Matching NLO QCD computations with parton shower simulations: the POWHEG method | JHEP 11 (2007) 070 | 0709.2092 |
| 20 | 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 |
| 21 | L. Barzè et al. | W$\gamma $ production in hadronic collisions using the POWHEG+MiNLO method | JHEP 12 (2014) 039 | 1408.5766 |
| 22 | T. Sjostrand et al. | An Introduction to PYTHIA 8.2 | CPC 191 (2015) 159 | 1410.3012 |
| 23 | S. Agostinelli et al. | GEANT4--a simulation toolkit | NIMA 506 (2003) 250 | |
| 24 | CMS Collaboration | Event generator tunes obtained from underlying event and multiparton scattering measurements | EPJC 76 (2016) 155 | CMS-GEN-14-001 1512.00815 |
| 25 | R. D. Ball et al. | Parton distributions for the LHC run II | JHEP 04 (2015) 040 | 1410.8849 |
| 26 | CMS Collaboration | Extraction and validation of a new set of CMS PYTHIA8 tunes from underlying-event measurements | EPJC 80 (2020) 4 | CMS-GEN-17-001 1903.12179 |
| 27 | NNPDF Collaboration | Parton distributions from high-precision collider data | EPJC 77 (2017) 663 | 1706.00428 |
| 28 | CMS Collaboration | The CMS trigger system | Journal of Instrumentation 12 (2017) P01020 | CMS-TRG-12-001 1609.02366 |
| 29 | CMS Collaboration | Measurement of the cross section for electroweak production of a Z boson, a photon and two jets in proton-proton collisions at $ \sqrt{s} = $ 13 TeV and constraints on anomalous quartic couplings | JHEP 06 (2020) 076 | CMS-SMP-18-007 2002.09902 |
| 30 | M. Abadi et al. | TensorFlow: Large-scale machine learning on heterogeneous systems | 2015 Software available from tensorflow.org. \url https://www.tensorflow.org/ | |
| 31 | CMS Collaboration | Measurement of the W boson rapidity, helicity, and differential cross sections in pp collisions at $\sqrt{s}=$ 13 TeV | Accepted by PRD | CMS-SMP-18-012 2008.04174 |
| 32 | J. Butterworth et al. | PDF4LHC recommendations for LHC Run II | Journal of Physics G: Nuclear and Particle Physics 43 (2016) 023001 | 1510.03865 |
| 33 | L. A. Harland-Lang, A. D. Martin, P. Motylinski, and R. S. Thorne | Parton distributions in the LHC era: MMHT 2014 PDFs | The European Physical Journal C 75 (2015) 204 | 1412.3989 |
| 34 | S. Dulat et al. | New parton distribution functions from a global analysis of quantum chromodynamics | PRD 93 (2016) 033006 | 1506.07443 |
| 35 | O. Mattelaer | On the maximal use of Monte Carlo samples: re-weighting events at NLO accuracy | The European Physical Journal C 76 (2016) 674 | 1607.00763 |
| 36 | The ATLAS Collaboration, The CMS Collaboration, The LHC Higgs Combination Group Collaboration | Procedure for the LHC Higgs boson search combination in Summer 2011 | CMS-NOTE-2011-005 | |
|
|
Compact Muon Solenoid LHC, CERN |
|
|
|
|
|
|