Compact Muon Solenoid
LHC, CERN
Visit us: CMS Public Website, CMS Physics ;
Contact us: CMS Publications Committee
| CMS-TOP-22-001 ; CERN-EP-2024-020 | ||
| Combination of measurements of the top quark mass from data collected by the ATLAS and CMS experiments at $ \sqrt{s}= $ 7 and 8 TeV | ||
| ATLAS and CMS Collaborations | ||
| 13 February 2024 | ||
| Accepted for publication in Phys. Rev. Lett. | ||
| Abstract: A combination of fifteen top quark mass measurements performed by the ATLAS and CMS experiments at the LHC is presented. The data sets used correspond to an integrated luminosity of up to 5 and 20 fb$ ^{-1} $ of proton-proton collisions at center-of-mass energies of 7 and 8 TeV, respectively. The combination includes measurements in top quark pair events that exploit both the semileptonic and hadronic decays of the top quark, and a measurement using events enriched in single top quark production via the electroweak $ t $-channel. The combination accounts for the correlations between measurements and achieves an improvement in the total uncertainty of 31% relative to the most precise input measurement. The result is $ m_{\mathrm{t}} = $ 172.52 $ \pm $ 0.14 (stat) $ \pm $ 0.30 (syst) GeV, with a total uncertainty of 0.33 GeV. | ||
| Links: e-print arXiv:2402.08713 [hep-ex] (PDF) ; CDS record ; inSPIRE record ; Physics Briefing ; CADI line (restricted) ; | ||
| Figures | |
png pdf |
Figure 1:
Comparison of the individual $ m_{\mathrm{t}} $ measurements and the result of the $ m_{\mathrm{t}} $ combination. Also shown are the separate combinations of each experiment and the result of the simultaneous combination for the different decay channels, where the ``other'' category covers the single top, J$ /\psi $, and secondary vertex measurements. |
png pdf |
Figure 1-a:
Comparison of the individual $ m_{\mathrm{t}} $ measurements and the result of the $ m_{\mathrm{t}} $ combination. Also shown are the separate combinations of each experiment and the result of the simultaneous combination for the different decay channels, where the ``other'' category covers the single top, J$ /\psi $, and secondary vertex measurements. |
png pdf |
Figure 1-b:
Comparison of the individual $ m_{\mathrm{t}} $ measurements and the result of the $ m_{\mathrm{t}} $ combination. Also shown are the separate combinations of each experiment and the result of the simultaneous combination for the different decay channels, where the ``other'' category covers the single top, J$ /\psi $, and secondary vertex measurements. |
png pdf |
Figure 2:
The simultaneous extraction of the $ m_{\mathrm{t}} $ measured by ATLAS ($ m_{\mathrm{t}}^\text{ATLAS} $) and CMS ($ m_{\mathrm{t}}^\text{CMS} $) from a BLUE combination of the 15 input measurements is shown by the star. The solid ellipses show the regions allowed at 68 and 95% confidence level (CL) by the combination and are in good agreement with the expectation $ m_{\mathrm{t}}^\text{ATLAS}=m_{\mathrm{t}}^\text{CMS} $ (shown by the black dashed line). The observed correlation between $ m_{\mathrm{t}}^\text{ATLAS} $ and $ m_{\mathrm{t}}^\text{CMS} $ is 0.15. The blue and red lines and bands show the central values and 68% CL intervals for the individual ATLAS and CMS combinations, which use the 6 ATLAS and 9 CMS measurements, respectively. In addition, the central value of the LHC combination, $ m_{\mathrm{t}}^\text{LHC} $, which assumes $ m_{\mathrm{t}}^\text{LHC}=m_{\mathrm{t}}^\text{ATLAS}=m_{\mathrm{t}}^\text{CMS} $, is shown by the circular marker. The projection of the corresponding diagonal error bar on either axis represents the total uncertainty $ m_{\mathrm{t}}^\text{LHC} $. |
png pdf |
Figure 3:
Correlation matrix for the ATLAS and CMS 7 and 8 TeV $ m_{\mathrm{t}} $ measurements in the dilepton (``dil''), lepton+jets (``lj''), and all-jets (``aj'') channels, and for the CMS 8 TeV $ m_{\mathrm{t}} $ measurements in the single top (``t''), secondary vertex (``vtx''), and J$ /\psi $ analysis (``J$ /\psi $''). |
| Tables | |
png pdf |
Table 1:
Correlation strengths $ \rho $ of the systematic uncertainty categories between ATLAS and CMS, as used in the combination. The categories are defined in the text. Categories indicated with the symbol $ \text{---} $ in the second column correspond to uncertainties specific to a single experiment. The third column shows the range of $ \rho $ scanned for stability checks. The changes in the combination's central value $ m_{\mathrm{t}} $ and uncertainty $ \sigma_{m_{\mathrm{t}}} $ corresponding to each correlation variation are shown in the last two columns. |
png pdf |
Table 2:
Uncertainties on the $ m_{\mathrm{t}} $ values extracted in the LHC, ATLAS, and CMS combinations arising from different categories. |
png pdf |
Table 3:
BLUE weights of the simultaneous ATLAS and CMS combination for each input measurement. The input measurements are the ATLAS and CMS 7 and 8 TeV $ m_{\mathrm{t}} $ measurements in the dilepton (``dil''), lepton+jets (``lj''), and all-jets (``aj'') channels, and the CMS 8 TeV $ m_{\mathrm{t}} $ measurements in the single top (``t''), secondary vertex (``vtx''), and J$ /\psi $ analysis (``J$ /\psi $''). The sum of the ATLAS weights in the CMS combined value is zero, and vice versa. The individual weights, however, are different from zero due to the correlation between the different experiments. The weights are rounded to two decimal places; when the full precision is used, the weights for each of $ m_{\mathrm{t}}^\text{ATLAS} $ and $ m_{\mathrm{t}}^\text{CMS} $ sum to one. |
png pdf |
Table 4:
Results and systematic uncertainties of the ATLAS $ m_{\mathrm{t}} $ measurements, shown separately for the 7 and 8 TeV results in the dilepton (``dil''), lepton+jets (``lj''), and all-jets (``aj'') channels, and for their combination (``comb.''). All values are given in GeVns. |
png pdf |
Table 5:
Results and systematic uncertainties of the CMS $ m_{\mathrm{t}} $ measurements, shown separately for the 7 and 8 TeV results in the dilepton (``dil''), lepton+jets (``lj''), and all-jets (``aj'') channels, for the 8 TeV results in the single top (``t''), secondary vertex (``vtx''), and J$ /\psi $ analysis (``J$ /\psi $''), and for their combination (``comb.''). All values are given in GeVns. |
png pdf |
Table 6:
Pulls and weights of each input measurement in the LHC combination. The input measurements are the ATLAS and CMS 7 and 8 TeV $ m_{\mathrm{t}} $ measurements in the dilepton (``dil''), lepton+jets (``lj''), and all-jets (``aj'') channels, and the CMS 8 TeV $ m_{\mathrm{t}} $ measurements in the single top (``t'), secondary vertex (``vtx''), and J$ /\psi $ analysis (``J$ /\psi $''). The pull for measurement $ i $ is defined as $ (m_i - m_c)/\sqrt{\smash[b]{\sigma_i^2 - \sigma_c^2}} $, where $ m_i $ ($ \sigma_i $) is the central value (uncertainty) of the measurement and $ m_c $ ($ \sigma_c $) is the central value (uncertainty) of the LHC combination. The weights are rounded to two decimal places; when the full precision is used, the weights sum to one. |
png pdf |
Table 7:
Weights for each input measurement for the simultaneous combination of the four different channels. The input measurements are the ATLAS and CMS 7 and 8 TeV $ m_{\mathrm{t}} $ measurements in the dilepton (``dil''), lepton+jets (``lj''), and all-jets (``aj'') channels, and the CMS 8 TeV $ m_{\mathrm{t}} $ measurements in the single top (``t''), secondary vertex (``vtx''), and J$ /\psi $ analysis (``J$ /\psi $''). The CMS alternative measurements are assigned to the ``Other'' channel. |
png pdf |
Table 8:
Correlation matrix for the simultaneous combination of the dilepton (``dil''), lepton+jets (``lj''), all-jets (``aj''), and other (``Other'') channels. |
| Summary |
| In summary, a combination of top quark mass measurements by the ATLAS and CMS experiments at the CERN LHC in proton-proton collisions at $ \sqrt{s}= $ 7 and 8 TeV has been performed. The combination yields $ m_{\mathrm{t}} = $ 172.52 $ \pm $ 0.33 GeV, which is the most precise result to date. |
| References | ||||
| 1 | ALEPH, CDF, D0, DELPHI, L3, OPAL, and SLD Collaborations, LEP Electroweak Working Group, Tevatron Electroweak Working Group, and SLD electroweak and heavy flavour groups | Precision electroweak measurements and constraints on the standard model | 1012.2367 | |
| 2 | G. Degrassi et al. | Higgs mass and vacuum stability in the standard model at NNLO | JHEP 08 (2012) 098 | 1205.6497 |
| 3 | F. Bezrukov, M. Y. Kalmykov, B. A. Kniehl, and M. Shaposhnikov | Higgs boson mass and new physics | JHEP 10 (2012) 140 | 1205.2893 |
| 4 | F. L. Bezrukov and M. Shaposhnikov | The standard model Higgs boson as the inflaton | PLB 659 (2008) 703 | 0710.3755 |
| 5 | A. De Simone, M. P. Hertzberg, and F. Wilczek | Running inflation in the standard model | PLB 678 (2009) 1 | 0812.4946 |
| 6 | CDF Collaboration | Observation of top quark production in $ {\overline{\mathrm{p}}\mathrm{p}} $ collisions with the Collider Detector at Fermilab | PRL 74 (1995) 2626 | hep-ex/9503002 |
| 7 | D0 Collaboration | Observation of the top quark | PRL 74 (1995) 2632 | hep-ex/9503003 |
| 8 | CDF and D0 Collaborations | Combination of CDF and D0 results on the mass of the top quark using up to 9.7 fb$ ^{-1} $ at the Tevatron | 1608.01881 | |
| 9 | ATLAS Collaboration | The ATLAS experiment at the CERN Large Hadron Collider | JINST 3 (2008) S08003 | |
| 10 | CMS Collaboration | The CMS experiment at the CERN LHC | JINST 3 (2008) S08004 | |
| 11 | CMS Collaboration | Measurement of the top-quark mass in $ \mathrm{t} \overline{\mathrm{t}} $ events with lepton+jets final states in $ {\mathrm{p}\mathrm{p}} $ collisions at $ \sqrt{s}= $ 7 TeV | JHEP 12 (2012) 105 | CMS-TOP-11-015 1209.2319 |
| 12 | CMS Collaboration | Measurement of the top-quark mass in $ \mathrm{t} \overline{\mathrm{t}} $ events with dilepton final states in $ {\mathrm{p}\mathrm{p}} $ collisions at $ \sqrt{s}= $ 7 TeV | EPJC 72 (2012) 2202 | CMS-TOP-11-016 1209.2393 |
| 13 | CMS Collaboration | Measurement of the top-quark mass in all-jets $ \mathrm{t} \overline{\mathrm{t}} $ events in $ {\mathrm{p}\mathrm{p}} $ collisions at $ \sqrt{s}= $ 7 TeV | EPJC 74 (2014) 2758 | CMS-TOP-11-017 1307.4617 |
| 14 | ATLAS Collaboration | Measurement of the top-quark mass in the fully hadronic decay channel from ATLAS data at $ \sqrt{s}= $ 7 TeV | EPJC 75 (2015) 158 | 1409.0832 |
| 15 | ATLAS Collaboration | Measurement of the top quark mass in the $ {\mathrm{t}\overline{\mathrm{t}}} \to $lepton+jets and $ {\mathrm{t}\overline{\mathrm{t}}} \to $dilepton channels using $ \sqrt{s}= $ 7 TeV ATLAS data | EPJC 75 (2015) 330 | 1503.05427 |
| 16 | CMS Collaboration | Measurement of the top quark mass using proton-proton data at $ \sqrt{s}= $ 7 and 8 TeV | PRD 93 (2016) 072004 | CMS-TOP-14-022 1509.04044 |
| 17 | CMS Collaboration | Measurement of the top quark mass using charged particles in $ {\mathrm{p}\mathrm{p}} $ collisions at $ \sqrt{s}= $ 8 TeV | PRD 93 (2016) 092006 | CMS-TOP-12-030 1603.06536 |
| 18 | ATLAS Collaboration | Measurement of the top quark mass in the $ {\mathrm{t}\overline{\mathrm{t}}} \to $dilepton channel from $ \sqrt{s}= $ 8 TeV | PLB 761 (2016) 350 | 1606.02179 |
| 19 | CMS Collaboration | Measurement of the mass of the top quark in decays with a $ \mathrm{J}/\psi $ meson in $ {\mathrm{p}\mathrm{p}} $ collisions at 8 TeV | JHEP 12 (2016) 123 | CMS-TOP-15-014 1608.03560 |
| 20 | ATLAS Collaboration | Top-quark mass measurement in the all-hadronic $ \mathrm{t} \overline{\mathrm{t}} $ decay channel at $ \sqrt{s}= $ 8 TeV with the ATLAS detector | JHEP 09 (2017) 118 | 1702.07546 |
| 21 | CMS Collaboration | Measurement of the top quark mass using single top quark events in proton-proton collisions at $ \sqrt{s}= $ 8 TeV | EPJC 77 (2017) 354 | CMS-TOP-15-001 1703.02530 |
| 22 | CMS Collaboration | Measurement of the top quark mass in the dileptonic $ \mathrm{t} \overline{\mathrm{t}} $ decay channel using the mass observables $ {M}_{\mathrm{b}\ell} $, $ {M}_{{\mathrm{T}2}} $, and $ m_{\mathrm{b}\ell\nu} $ in $ {\mathrm{p}\mathrm{p}} $ collisions at $ \sqrt{s}= $ 8 TeV | PRD 96 (2017) 032002 | CMS-TOP-15-008 1704.06142 |
| 23 | ATLAS Collaboration | Measurement of the top quark mass in the $ {\mathrm{t}\overline{\mathrm{t}}} \to $lepton+jets channel from $ \sqrt{s}= $ 8 TeV ATLAS data and combination with previous results | EPJC 79 (2019) 290 | 1810.01772 |
| 24 | L. Lyons, D. Gibaut, and P. Clifford | How to combine correlated estimates of a single physical quantity | NIM A 270 (1988) 110 | |
| 25 | R. Nisius | BLUE: Combining correlated estimates of physics observables within \textscroot using the best linear unbiased estimate method | SoftwareX 11 (2020) 100468 | 2001.10310 |
| 26 | CMS Collaboration | Measurement of the top quark mass with lepton+jets final states using $ {\mathrm{p}\mathrm{p}} $ collisions at $ \sqrt{s}= $ 13 TeV | EPJC 78 (2018) 891 | CMS-TOP-17-007 1805.01428 |
| 27 | CMS Collaboration | Measurement of the top quark mass in the all-jets final state at $ \sqrt{s}= $ 13 TeV and combination with the lepton+jets channel | EPJC 79 (2019) 313 | CMS-TOP-17-008 1812.10534 |
| 28 | CMS Collaboration | Measurement of the $ \mathrm{t} \overline{\mathrm{t}} $ production cross section, the top quark mass, and the strong coupling constant using dilepton events in $ {\mathrm{p}\mathrm{p}} $ collisions at $ \sqrt{s}= $ 13 TeV | EPJC 79 (2019) 368 | CMS-TOP-17-001 1812.10505 |
| 29 | CMS Collaboration | Measurement of the jet mass distribution and top quark mass in hadronic decays of boosted top quarks in $ {\mathrm{p}\mathrm{p}} $ collisions at $ \sqrt{s}= $ 13 TeV | PRL 124 (2020) 202001 | CMS-TOP-19-005 1911.03800 |
| 30 | CMS Collaboration | Measurement of the top quark mass using events with a single reconstructed top quark in $ {\mathrm{p}\mathrm{p}} $ collisions at $ \sqrt{s}= $ 13 TeV | JHEP 12 (2021) 161 | CMS-TOP-19-009 2108.10407 |
| 31 | ATLAS Collaboration | Measurement of the top-quark mass using a leptonic invariant mass in $ {\mathrm{p}\mathrm{p}} $ collisions at $ \sqrt{s}= $ 13 TeV with the ATLAS detector | JHEP 06 (2023) 019 | 2209.00583 |
| 32 | CMS Collaboration | Measurement of the top quark mass using a profile likelihood approach with the lepton+jets final states in proton-proton collisions at $ \sqrt{s}= $ 13 TeV | EPJC 83 (2023) 963 | CMS-TOP-20-008 2302.01967 |
| 33 | P. Nason | A new method for combining NLO QCD with shower Monte Carlo algorithms | JHEP 11 (2004) 040 | hep-ph/0409146 |
| 34 | S. Frixione, P. Nason, and C. Oleari | Matching NLO QCD computations with parton shower simulations: the POWHEG method | JHEP 11 (2007) 070 | 0709.2092 |
| 35 | S. Alioli, P. Nason, C. Oleari, and E. Re | A general framework for implementing NLO calculations in shower Monte Carlo programs: the POWHEG \textscbox | JHEP 06 (2010) 043 | 1002.2581 |
| 36 | T. Sjöstrand, S. Mrenna, and P. Z. Skands | PYTHIA6.4 physics and manual | JHEP 05 (2006) 026 | hep-ph/0603175 |
| 37 | J. Alwall et al. | MadGraph 5: going beyond | JHEP 06 (2011) 128 | 1106.0522 |
| 38 | A. H. Hoang, S. Pl ä tzer, and D. Samitz | On the cutoff dependence of the quark mass parameter in angular ordered parton showers | JHEP 10 (2018) 200 | 1807.06617 |
| 39 | P. Azzi et al. | Report from working group 1: Standard model physics at the HL-LHC and HE-LHC | CERN Report CERN-LPCC-2018-03, 2019 link |
1902.04070 |
| 40 | A. H. Hoang | What is the top quark mass? | Ann. Rev. Nucl. Part. Sci. 70 (2020) 225 | 2004.12915 |
| 41 | B. Dehnadi, A. H. Hoang, O. L. Jin, and V. Mateu | Top quark mass calibration for Monte Carlo event generators---an update | JHEP 12 (2023) 065 | 2309.00547 |
| 42 | ATLAS and CMS Collaborations | Placeholder for journal link to supplemental material, 2024 | ||
| 43 | E. Maguire, L. Heinrich, and G. Watt | HEPData: a repository for high energy physics data | in Proc. 22nd International Conference on Computing in High Energy and Nuclear Physics (CHEP), San Francisco CA, USA, 2017 J. Phys. Conf. Ser. 898 (2017) 102006 |
1704.05473 |
| 44 | CMS Collaboration | HEPData record for this analysis | link | |
| 45 | ATLAS and CMS Collaborations | Jet energy scale uncertainty correlations between ATLAS and CMS | ATLAS PUB Note ATL-PHYS-PUB-2014-020, CMS Physics Analysis Summary, 2014 CMS-PAS-JME-14-003 |
CMS-PAS-JME-14-003 |
| 46 | ATLAS and CMS Collaborations | Jet energy scale uncertainty correlations between ATLAS and CMS at 8 TeV | ATLAS PUB Note ATL-PHYS-PUB-2015-049, CMS Physics Analysis Summary, 2015 CMS-PAS-JME-15-001 |
CMS-PAS-JME-15-001 |
| 47 | ATLAS Collaboration | Determination of jet calibration and energy resolution in proton-proton collisions at $ \sqrt{s}= $ 8 TeV using the ATLAS detector | EPJC 80 (2020) 1104 | 1910.04482 |
| 48 | CMS Collaboration | Jet energy scale and resolution in the CMS experiment in $ {\mathrm{p}\mathrm{p}} $ collisions at 8 TeV | JINST 12 (2017) P02014 | CMS-JME-13-004 1607.03663 |
| 49 | ATLAS Collaboration | Performance of b-jet identification in the ATLAS experiment | JINST 11 (2016) P04008 | 1512.01094 |
| 50 | CMS Collaboration | Identification of b-quark jets with the CMS experiment | JINST 8 (2013) P04013 | CMS-BTV-12-001 1211.4462 |
| 51 | S. Frixione and B. R. Webber | Matching NLO QCD computations and parton shower simulations | JHEP 06 (2002) 029 | hep-ph/0204244 |
| 52 | S. Frixione, P. Nason, and B. R. Webber | Matching NLO QCD and parton showers in heavy flavour production | JHEP 08 (2003) 007 | hep-ph/0305252 |
| 53 | G. Corcella et al. | HERWIG 6: an event generator for hadron emission reactions with interfering gluons (including supersymmetric processes) | JHEP 01 (2001) 010 | hep-ph/0011363 |
| 54 | ATLAS Collaboration | Measurements of top-quark pair differential cross-sections in the lepton+jets channel in $ {\mathrm{p}\mathrm{p}} $ collisions at $ \sqrt{s}= $ 8 TeV using the ATLAS detector | EPJC 76 (2016) 538 | 1511.04716 |
| 55 | J. Kieseler | A method and tool for combining differential or inclusive measurements obtained with simultaneously constrained uncertainties | EPJC 77 (2017) 792 | 1706.01681 |
| 56 | T. Ježo et al. | An NLO+PS generator for $ \mathrm{t} \overline{\mathrm{t}} $ and $ {\mathrm{W}\mathrm{t}} $ production and decay including non-resonant and interference effects | EPJC 76 (2016) 691 | 1607.04538 |
| 57 | ATLAS Collaboration | Improvements in $ \mathrm{t} \overline{\mathrm{t}} $ modelling using NLO+PS Monte Carlo generators for \mboxRun 2 | ATLAS PUB Note ATL-PHYS-PUB-2018-009, 2018 | |
| 58 | CMS Collaboration | Investigations of the impact of the parton shower tuning in PYTHIA8 in the modelling of $ \mathrm{t} \overline{\mathrm{t}} $ at $ \sqrt{s}= $ 8 and 13 TeV | CMS Physics Analysis Summary, 2016 CMS-PAS-TOP-16-021 |
CMS-PAS-TOP-16-021 |
| 59 | S. Argyropoulos and T. Sjöstrand | Effects of color reconnection on $ \mathrm{t} \overline{\mathrm{t}} $ final states at the LHC | JHEP 11 (2014) 043 | 1407.6653 |
| 60 | J. R. Christiansen and P. Z. Skands | String formation beyond leading colour | JHEP 08 (2015) 003 | 1505.01681 |
| 61 | J. Mazzitelli et al. | Top-pair production at the LHC with MINNLO\textsubscriptPS | JHEP 04 (2022) 079 | 2112.12135 |
| 62 | H. Brooks and P. Skands | Coherent showers in decays of colored resonances | PRD 100 (2019) 076006 | 1907.08980 |
| 63 | ATLAS Collaboration | ATLAS Computing Acknowledgements | technical report, CERN, Geneva, 2023 | |
| 64 | ATLAS Collaboration | The ATLAS simulation infrastructure | EPJC 70 (2010) 823 | 1005.4568 |
| 65 | T. Sjöstrand et al. | An introduction to PYTHIA8.2 | Comput. Phys. Commun. 191 (2015) 159 | 1410.3012 |
| 66 | R. Nisius | On the combination of correlated estimates of a physics observable | EPJC 74 (2014) 3004 | 1402.4016 |
|
|
Compact Muon Solenoid LHC, CERN |
|
|
|
|
|
|