CMS-TOP-17-007

CMS-TOP-17-007 ; CERN-EP-2018-063
Measurement of the top quark mass with lepton+jets final states using pp collisions at $\sqrt{s}= $ 13 TeV
CMS Collaboration
3 May 2018
Eur. Phys. J. C 78 (2018) 891
Abstract: The mass of the top quark is measured using a sample of $ \mathrm{t\bar{t}} $ events containing one isolated muon or electron and at least four jets in the final state, collected by the CMS detector using proton-proton collisions at $\sqrt{s}=$ 13 TeV at the CERN LHC. The events are selected from data corresponding to an integrated luminosity of 35.9 fb$^{-1}$. For each event the mass is reconstructed from a kinematic fit of the decay products to a $ \mathrm{t\bar{t}} $ hypothesis. Using the ideogram method, the top quark mass is determined simultaneously with an overall jet energy scale factor (JSF), constrained by the mass of the W boson in $ \mathrm{q\bar{q}'} $ decays. The measurement is calibrated on samples simulated at next-to-leading order matched to a leading-order parton shower. The top quark mass is found to be 172.25 $\pm$ 0.08 (stat+JSF) $\pm$ 0.62 (syst) GeV. The dependence of this result on the kinematic properties of the event is studied and compared to predictions of different models of $ \mathrm{t\bar{t}} $ production, and no indications of a bias in the measurements are observed.
Links: e-print arXiv:1805.01428 [hep-ex] (PDF) ; CDS record ; inSPIRE record ; HepData record ; CADI line (restricted) ;

Figures & Tables	Summary	References	CMS Publications

Figures
png pdf	Figure 1: Invariant mass $m_ {\mathrm {W}}^\text {reco}$ of the two untagged jets (left) and invariant mass $ {m_{{\mathrm {t}}}} ^\text {reco}$ of the two untagged jets and one of the b-tagged jets (right) after the b tagging requirement. For the simulated $ {{\mathrm {t}\overline {\mathrm {t}}}} $ events, the jet-parton assignments are classified as correct, wrong, and unmatched permutations as described in the text. The vertical bars show the statistical uncertainty on the data and the hatched bands show the systematic uncertainties considered in Section 5. The lower portion of each panel shows the ratio of the yields between data and the simulation. The simulations are normalized to the integrated luminosity.
png pdf	Figure 1-a: Invariant mass $m_ {\mathrm {W}}^\text {reco}$ of the two untagged jets after the b tagging requirement. For the simulated $ {{\mathrm {t}\overline {\mathrm {t}}}} $ events, the jet-parton assignments are classified as correct, wrong, and unmatched permutations as described in the text. The vertical bars show the statistical uncertainty on the data and the hatched bands show the systematic uncertainties considered in Section 5. The lower portion of the panel shows the ratio of the yields between data and the simulation. The simulations are normalized to the integrated luminosity.
png pdf	Figure 1-b: Invariant mass $ {m_{{\mathrm {t}}}} ^\text {reco}$ of the two untagged jets and one of the b-tagged jets after the b tagging requirement. For the simulated $ {{\mathrm {t}\overline {\mathrm {t}}}} $ events, the jet-parton assignments are classified as correct, wrong, and unmatched permutations as described in the text. The vertical bars show the statistical uncertainty on the data and the hatched bands show the systematic uncertainties considered in Section 5. The lower portion of the panel shows the ratio of the yields between data and the simulation. The simulations are normalized to the integrated luminosity.
png pdf	Figure 2: Reconstructed W boson masses $m_ {\mathrm {W}}^\text {reco}$ (left) and fitted top quark masses $ {m_{{\mathrm {t}}}} ^\text {fit}$ (right) after the goodness-of-fit selection and the weighting by $P_\text {gof}$. Symbols and patterns are the same as in Fig. 1. The simulations are normalized to the integrated luminosity.
png pdf	Figure 2-a: Reconstructed W boson masses $m_ {\mathrm {W}}^\text {reco}$ after the goodness-of-fit selection and the weighting by $P_\text {gof}$. Symbols and patterns are the same as in Fig. 1. The simulations are normalized to the integrated luminosity.
png pdf	Figure 2-b: Fitted top quark masses $ {m_{{\mathrm {t}}}} ^\text {fit}$ after the goodness-of-fit selection and the weighting by $P_\text {gof}$. Symbols and patterns are the same as in Fig. 1. The simulations are normalized to the integrated luminosity.
png pdf	Figure 3: Measurements of $ {m_{{\mathrm {t}}}} $ as a function of the invariant mass of the $ {{\mathrm {t}\overline {\mathrm {t}}}} $ system $m_{{{\mathrm {t}\overline {\mathrm {t}}}}}$ (left) and the $\Delta R$ between the light-quark jets $\Delta R_{{{\mathrm {q}} {\overline {\mathrm {q}}} ^\prime}}$ (right) compared to different generator models. The filled circles represent the data, and the other symbols are for the simulations. For reasons of clarity, the horizontal bars indicating the bin widths are shown only for the data points and each of the simulations is shown as a single offset point with a vertical error bar representing its statistical uncertainty. The statistical uncertainty of the data is displayed by the inner error bars. For the outer error bars, the systematic uncertainties are added in quadrature.
png pdf	Figure 3-a: Measurements of $ {m_{{\mathrm {t}}}} $ as a function of the invariant mass of the $ {{\mathrm {t}\overline {\mathrm {t}}}} $ system $m_{{{\mathrm {t}\overline {\mathrm {t}}}}}$ compared to different generator models. The filled circles represent the data, and the other symbols are for the simulations. For reasons of clarity, the horizontal bars indicating the bin widths are shown only for the data points and each of the simulations is shown as a single offset point with a vertical error bar representing its statistical uncertainty. The statistical uncertainty of the data is displayed by the inner error bars. For the outer error bars, the systematic uncertainties are added in quadrature.
png pdf	Figure 3-b: Measurements of $ {m_{{\mathrm {t}}}} $ as a function of the $\Delta R$ between the light-quark jets $\Delta R_{{{\mathrm {q}} {\overline {\mathrm {q}}} ^\prime}}$ compared to different generator models. The filled circles represent the data, and the other symbols are for the simulations. For reasons of clarity, the horizontal bars indicating the bin widths are shown only for the data points and each of the simulations is shown as a single offset point with a vertical error bar representing its statistical uncertainty. The statistical uncertainty of the data is displayed by the inner error bars. For the outer error bars, the systematic uncertainties are added in quadrature.
png pdf	Figure 4: Measurements of $ {m_{{\mathrm {t}}}} $ as a function of the $\Delta R$ between the b jets $\Delta R_{{{\mathrm {b}} {\overline {\mathrm {b}}}}}$ (left) and the light-quark jets $\Delta R_{{{\mathrm {q}} {\overline {\mathrm {q}}} ^\prime}}$ (right) compared to alternative models of color reconnection. The symbols and conventions are the same as in Fig. 3.
png pdf	Figure 4-a: Measurements of $ {m_{{\mathrm {t}}}} $ as a function of the $\Delta R$ between the b jets $\Delta R_{{{\mathrm {b}} {\overline {\mathrm {b}}}}}$ compared to alternative models of color reconnection. The symbols and conventions are the same as in Fig. 3.
png pdf	Figure 4-b: Measurements of $ {m_{{\mathrm {t}}}} $ as a function of the light-quark jets $\Delta R_{{{\mathrm {q}} {\overline {\mathrm {q}}} ^\prime}}$ compared to alternative models of color reconnection. The symbols and conventions are the same as in Fig. 3.

Tables
png pdf	Table 1: Observed shifts with respect to the default simulation for different models of color reconnection. The "QCD inspired'' and "gluon move'' models are compared to the default model with ERDs. The statistical uncertainty in the JSF shifts is 0.1%.
png pdf	Table 2: Observed shifts with respect to the default simulation for different generator setups. The statistical uncertainty in the JSF shifts is 0.1%.
png pdf	Table 3: List of systematic uncertainties for the fits to the combined data set using the procedures described in Section 5. With the exception of the flavor-dependent JEC terms, the total systematic uncertainty is obtained from the sum in quadrature of the individual systematic uncertainties. The values in parentheses with indented labels are already included in the preceding uncertainty source. A positive sign indicates an increase in the value of $ {m_{{\mathrm {t}}}} $ or the JSF in response to a $+1\sigma $ shift and a negative sign indicates a decrease. The statistical uncertainty in the shift in $ {m_{{\mathrm {t}}}} $ is given when different samples are compared. The statistical uncertainty in the JSF shifts is 0.1% for these sources.
png pdf	Table 4: Compatibility of different models with the differential measurement of the top quark mass. For each variable and model, the probability of the cumulative $\chi ^2$ is computed. The setup with {powheg} v2 + {herwig++} does not use ME corrections to the top quark decay and shows large deviations from the data.

Summary

This study measured the mass of the top quark using the 2016 data at $\sqrt{s}=$ 13 TeV corresponding to an integrated luminosity of 35.9 fb$^{-1}$, and POWHEG v2 interfaced with PYTHIA 8 with the CUETP8M2T4 tune for the simulation. The top quark mass is measured to be 172.25 $\pm$ 0.08 (stat+JSF) $\pm$ 0.62 (syst) GeV from the selected lepton+jets events. The result is consistent with the CMS measurements of Run 1 of the LHC at $\sqrt{s}=$ 7 and 8 TeV, with no shift observed from the new experimental setup and the use of the next-to-leading-order matrix-element generator and the new parton-shower simulation and tune. Along with the new generator setup, a more advanced treatment of the modeling uncertainties with respect to the Run 1 analysis is employed. In particular, a broader set of color-reconnection models is considered. The top quark mass has also been studied as a function of the event-level kinematic properties, and no indications of a bias in the measurements are observed.

References
1	M. Baak et al.	The global electroweak fit at NNLO and prospects for the LHC and ILC	EPJC 74 (2014) 3046	1407.3792
2	G. Degrassi et al.	Higgs mass and vacuum stability in the Standard Model at NNLO	JHEP 08 (2012) 098	1205.6497
3	Particle Data Group, C. Patrignani et al.	Review of particle physics	CPC 40 (2016) 100001
4	CDF and D0 Collaborations	Combination of CDF and D0 results on the mass of the top quark using up to $ 9.7\:{\rm fb}^{-1} $ at the Tevatron		1608.01881
5	ATLAS Collaboration	Measurement of the top quark mass in the $ \mathrm{t\bar{t}}\to $ dilepton channel from $ \sqrt{s}= $ 8 TeV ATLAS data	PLB 761 (2016) 350	1606.02179
6	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
7	S. Moch et al.	High precision fundamental constants at the TeV scale		1405.4781
8	P. Marquard, A. V. Smirnov, V. A. Smirnov, and M. Steinhauser	Quark mass relations to four-loop order in perturbative QCD	PRL 114 (2015) 142002	1502.01030
9	M. Beneke, P. Marquard, P. Nason, and M. Steinhauser	On the ultimate uncertainty of the top quark pole mass	PLB 775 (2017) 63	1605.03609
10	M. Butenschoen et al.	Top quark mass calibration for Monte Carlo event generators	PRL 117 (2016) 232001	1608.01318
11	P. Nason	The top quark mass at the LHC	in 10th International Workshop on Top Quark Physics (TOP2017) Braga, Portugal, September 17-22, 2017 2018	1801.04826
12	CMS Collaboration	The CMS experiment at the CERN LHC	JINST 3 (2008) S08004	CMS-00-001
13	CMS Collaboration	Particle-flow reconstruction and global event description with the CMS detector	JINST 12 (2017) P10003	CMS-PRF-14-001 1706.04965
14	M. Cacciari and G. P. Salam	Dispelling the $ N^{3} $ myth for the $ k_{\rm t} $ jet-finder	PLB 641 (2006) 57	hep-ph/0512210
15	M. Cacciari, G. P. Salam, and G. Soyez	The anti-$ k_{\rm t} $ jet clustering algorithm	JHEP 04 (2008) 063	0802.1189
16	M. Cacciari, G. P. Salam, and G. Soyez	FastJet user manual	EPJC 72 (2012) 1896	1111.6097
17	M. Cacciari and G. P. Salam	Pileup subtraction using jet areas	PLB 659 (2008) 119	0707.1378
18	CMS Collaboration	Jet energy scale and resolution in the CMS experiment in pp collisions at 8 TeV	JINST 12 (2017) P02014	CMS-JME-13-004 1607.03663
19	CMS Collaboration	Jet algorithms performance in 13 TeV data	CMS-PAS-JME-16-003	CMS-PAS-JME-16-003
20	CMS Collaboration	CMS luminosity measurements for the 2016 data taking period	CMS-PAS-LUM-17-001	CMS-PAS-LUM-17-001
21	P. Nason	A new method for combining NLO QCD with shower Monte Carlo algorithms	JHEP 11 (2004) 040	hep-ph/0409146
22	S. Frixione, P. Nason, and C. Oleari	Matching NLO QCD computations with parton shower simulations: the POWHEG method	JHEP 11 (2007) 070	0709.2092
23	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
24	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
25	T. Sjostrand, S. Mrenna, and P. Skands	A brief introduction to PYTHIA 8.1	CPC 178 (2008) 852	0710.3820
26	P. Skands, S. Carrazza, and J. Rojo	Tuning PYTHIA 8.1: the Monash 2013 tune	EPJC 74 (2014) 3024	1404.5630
27	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
28	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
29	E. Re	Single-top Wt-channel production matched with parton showers using the POWHEG method	EPJC 71 (2011) 1547	1009.2450
30	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
31	J. Alwall et al.	Comparative study of various algorithms for the merging of parton showers and matrix elements in hadronic collisions	EPJC 53 (2008) 473	0706.2569
32	R. Frederix and S. Frixione	Merging meets matching in MC@NLO	JHEP 12 (2012) 061	1209.6215
33	NNPDF Collaboration	Parton distributions for the LHC Run II	JHEP 04 (2015) 040	1410.8849
34	M. Czakon and A. Mitov	Top++: A program for the calculation of the top-pair cross-section at hadron colliders	CPC 185 (2014) 2930	1112.5675
35	Y. Li and F. Petriello	Combining QCD and electroweak corrections to dilepton production in FEWZ	PRD 86 (2012) 094034	1208.5967
36	P. Kant et al.	HatHor for single top-quark production: Updated predictions and uncertainty estimates for single top-quark production in hadronic collisions	CPC 191 (2015) 74	1406.4403
37	N. Kidonakis	NNLL threshold resummation for top-pair and single-top production	Phys. Part. Nucl. 45 (2014) 714	1210.7813
38	GEANT4 Collaboration	GEANT4---a simulation toolkit	NIMA 506 (2003) 250
39	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
40	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
41	CMS Collaboration	Identification of heavy-flavour jets with the CMS detector in pp collisions at 13 TeV	Submitted to \it JINST	CMS-BTV-16-002 1712.07158
42	D0 Collaboration	Direct measurement of the top quark mass at D0	PRD 58 (1998) 052001	hep-ex/9801025
43	DELPHI Collaboration	Measurement of the mass and width of the W boson in $ {\rm e}^{+}{\rm e}^{-} $ collisions at $ \sqrt{s} = $ 161 -- 209 GeV	EPJC 55 (2008) 1	0803.2534
44	CMS Collaboration	Measurement of the top-quark mass in $ \mathrm{t\bar{t}} $ events with lepton+jets final states in pp collisions at $ \sqrt{s}= $ 7 TeV	JHEP 12 (2012) 105	CMS-TOP-11-015 1209.2319
45	S. Argyropoulos and T. Sjostrand	Effects of color reconnection on $ \mathrm{t\bar{t}} $ final states at the LHC	JHEP 11 (2014) 043	1407.6653
46	J. R. Christiansen and P. Skands	String formation beyond leading colour	JHEP 08 (2015) 003	1505.01681
47	ATLAS and CMS Collaborations	Jet energy scale uncertainty correlations between ATLAS and CMS at 8 TeV	ATL-PHYS-PUB-2015-049, CMS-PAS-JME-15-001
48	CMS Collaboration	Measurement of the $ t $-channel single-top-quark production cross section and of the $ \mid V_{tb} \mid $ CKM matrix element in pp collisions at $ \sqrt{s} = $ 8 TeV	JHEP 06 (2014) 090	CMS-TOP-12-038 1403.7366
49	CMS Collaboration	Cross section measurement of $ t $-channel single top quark production in pp collisions at $ \sqrt s = $ 13 TeV	PLB 772 (2017) 752	CMS-TOP-16-003 1610.00678
50	CMS Collaboration	Measurement of the production cross section of a W boson in association with two b jets in pp collisions at $ \sqrt{s} = $ 8 TeV	Eur. Phys. J C. 77 (2017) 92	CMS-SMP-14-020 1608.07561
51	CMS Collaboration	Measurements of the associated production of a Z boson and b jets in pp collisions at $ {\sqrt{s}} = $ 8 TeV	EPJC 77 (2017) 751	CMS-SMP-14-010 1611.06507
52	CMS Collaboration	Measurement of the WZ production cross section in pp collisions at $ \sqrt{s} = $ 13 TeV	PLB 766 (2017) 268	CMS-SMP-16-002 1607.06943
53	CMS Collaboration	Measurements of the $ \mathrm {p}\mathrm {p}\rightarrow \mathrm{Z}\mathrm{Z} $ production cross section and the $ \mathrm{Z}\rightarrow 4\ell $ branching fraction, and constraints on anomalous triple gauge couplings at $ \sqrt{s} = $ 13 TeV	EPJC 78 (2018) 165	CMS-SMP-16-017 1709.08601
54	T. Sjostrand, S. Mrenna, and P. Skands	PYTHIA 6.4 physics and manual	JHEP 05 (2006) 026	hep-ph/0603175
55	M. Bahr et al.	Herwig++ physics and manual	EPJC 58 (2008) 639	0803.0883
56	ALEPH Collaboration	Study of the fragmentation of b quarks into B mesons at the Z peak	PLB 512 (2001) 30	hep-ex/0106051
57	DELPHI Collaboration	A study of the b-quark fragmentation function with the DELPHI detector at LEP I and an averaged distribution obtained at the Z pole	EPJC 71 (2011) 1557	1102.4748
58	M. G. Bowler	$ {\rm e}^{+}{\rm e}^{-} $ Production of heavy quarks in the string model	Z. Phys. 11 (1981) 169
59	C. Peterson, D. Schlatter, I. Schmitt, and P. M. Zerwas	Scaling violations in inclusive $ {\rm e}^{+}{\rm e}^{-} $ annihilation spectra	PRD 27 (1983) 105
60	J. Rojo et al.	The PDF4LHC report on PDFs and LHC data: Results from Run I and preparation for Run II	JPG 42 (2015) 103103	1507.00556
61	J. Butterworth et al.	PDF4LHC recommendations for LHC Run II	JPG 43 (2016) 023001	1510.03865
62	A. Accardi et al.	A critical appraisal and evaluation of modern PDFs	EPJC 76 (2016) 471	1603.08906
63	M. Czakon, D. Heymes, and A. Mitov	High-precision differential predictions for top-quark pairs at the LHC	PRL 116 (2016) 082003	1511.00549
64	CMS Collaboration	Measurement of differential cross sections for top quark pair production using the lepton+jets final state in proton-proton collisions at 13 TeV	PRD 95 (2017) 092001	CMS-TOP-16-008 1610.04191
65	CMS Collaboration	Measurement of normalized differential $ \mathrm{t\bar{t}} $ cross sections in the dilepton channel from pp collisions at $ \sqrt{s} = $ 13 TeV	Submitted to JHEP	CMS-TOP-16-007 1708.07638
66	M. H. Seymour and A. Siodmok	Constraining MPI models using $ \sigma_{eff} $ and recent Tevatron and LHC underlying event data	JHEP 10 (2013) 113	1307.5015
67	CMS Collaboration	Measurement of differential cross sections for the production of top quark pairs and of additional jets in lepton+jets events from pp collisions at $ \sqrt{s} = $ 13 TeV	Submitted to \it PRD	CMS-TOP-17-002 1803.08856
68	J. Alwall et al.	MadGraph 5: going beyond	JHEP 06 (2011) 128	1106.0522
69	R. Field	Early LHC underlying event data---findings and surprises		1010.3558