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| CMS-PAS-B2G-20-010 | ||
| Search for a heavy resonance decaying into a top quark and a W boson in the lepton+jets final state at 13 TeV | ||
| CMS Collaboration | ||
| March 2021 | ||
| Abstract: A search for a heavy resonance decaying into a top quark and a W boson in proton-proton collisions at $\sqrt{s}= $ 13 TeV is presented. The data analyzed were recorded with the CMS detector at the LHC and correspond to an integrated luminosity of 137 fb$^{-1}$. The search is performed in the lepton+jets final state, where the lepton is either an electron or muon. The top quark is reconstructed with a single jet and the W boson from its decay into a charged lepton and a neutrino. A top quark tagging technique based on a jet clustering with variable distance parameter and inherent jet grooming is used to identify jets from the collimated top quark decay. An excited bottom quark $\mathrm{b}^{*}$ model is used as a benchmark. A combination with an analysis in the all-hadronic final state is performed. At 95% confidence level, $\mathrm{b}^{*}$ masses up to 2.95, 3.03 and 3.22 TeV are excluded for left-handed, right-handed and vector-like couplings, respectively. | ||
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Links:
CDS record (PDF) ;
inSPIRE record ;
CADI line (restricted) ;
These preliminary results are superseded in this paper, Submitted to Figure_. The superseded preliminary plots can be found here. |
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| Figures | |
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Figure 1:
Distribution of $\alpha $ as a function of ${M_{\mathrm{t} \mathrm{W}}}$ for the background estimation in the 1b (left) and 2b (right) categories. Two different parametrizations are fitted to the distributions (solid lines) and the total uncertainty is shown as colored area. |
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Figure 1-a:
Distribution of $\alpha $ as a function of ${M_{\mathrm{t} \mathrm{W}}}$ for the background estimation in the 1b (left) and 2b (right) categories. Two different parametrizations are fitted to the distributions (solid lines) and the total uncertainty is shown as colored area. |
png pdf |
Figure 1-b:
Distribution of $\alpha $ as a function of ${M_{\mathrm{t} \mathrm{W}}}$ for the background estimation in the 1b (left) and 2b (right) categories. Two different parametrizations are fitted to the distributions (solid lines) and the total uncertainty is shown as colored area. |
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Figure 2:
Distributions of ${M_{\mathrm{t} \mathrm{W}}}$ in the 1b (left) and 2b (right) categories. The data are shown by closed markers, where the horizontal bars indicate the bin widths. The individual background contributions are given by filled histograms, the signal is shown by a dashed line. The shaded region is the uncertainty in the total background estimate. The lower panels of each figure show the ratio of data to the background estimate, with the total uncertainty displayed as gray area. |
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Figure 2-a:
Distributions of ${M_{\mathrm{t} \mathrm{W}}}$ in the 1b (left) and 2b (right) categories. The data are shown by closed markers, where the horizontal bars indicate the bin widths. The individual background contributions are given by filled histograms, the signal is shown by a dashed line. The shaded region is the uncertainty in the total background estimate. The lower panels of each figure show the ratio of data to the background estimate, with the total uncertainty displayed as gray area. |
png pdf |
Figure 2-b:
Distributions of ${M_{\mathrm{t} \mathrm{W}}}$ in the 1b (left) and 2b (right) categories. The data are shown by closed markers, where the horizontal bars indicate the bin widths. The individual background contributions are given by filled histograms, the signal is shown by a dashed line. The shaded region is the uncertainty in the total background estimate. The lower panels of each figure show the ratio of data to the background estimate, with the total uncertainty displayed as gray area. |
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Figure 3:
Upper limits on the production cross section of the left-handed (top left), right-handed (top right) and vector-like (bottom) ${\mathrm{b} ^{*}} $ hypotheses at 95% CL. Dashed colored lines show the expected limits from the $\ell $+jets and all-hadronic channels, where the latter start at ${\mathrm{b} ^{*}} $ masses of 1.4 TeV. The observed and expected limits from the combination are shown as solid and dashed black lines, respectively. The green and yellow bands show the 68% and 95% confidence intervals on the combined expected limits. The theoretical cross section is shown as dotted line. |
png pdf |
Figure 3-a:
Upper limits on the production cross section of the left-handed (top left), right-handed (top right) and vector-like (bottom) ${\mathrm{b} ^{*}} $ hypotheses at 95% CL. Dashed colored lines show the expected limits from the $\ell $+jets and all-hadronic channels, where the latter start at ${\mathrm{b} ^{*}} $ masses of 1.4 TeV. The observed and expected limits from the combination are shown as solid and dashed black lines, respectively. The green and yellow bands show the 68% and 95% confidence intervals on the combined expected limits. The theoretical cross section is shown as dotted line. |
png pdf |
Figure 3-b:
Upper limits on the production cross section of the left-handed (top left), right-handed (top right) and vector-like (bottom) ${\mathrm{b} ^{*}} $ hypotheses at 95% CL. Dashed colored lines show the expected limits from the $\ell $+jets and all-hadronic channels, where the latter start at ${\mathrm{b} ^{*}} $ masses of 1.4 TeV. The observed and expected limits from the combination are shown as solid and dashed black lines, respectively. The green and yellow bands show the 68% and 95% confidence intervals on the combined expected limits. The theoretical cross section is shown as dotted line. |
png pdf |
Figure 3-c:
Upper limits on the production cross section of the left-handed (top left), right-handed (top right) and vector-like (bottom) ${\mathrm{b} ^{*}} $ hypotheses at 95% CL. Dashed colored lines show the expected limits from the $\ell $+jets and all-hadronic channels, where the latter start at ${\mathrm{b} ^{*}} $ masses of 1.4 TeV. The observed and expected limits from the combination are shown as solid and dashed black lines, respectively. The green and yellow bands show the 68% and 95% confidence intervals on the combined expected limits. The theoretical cross section is shown as dotted line. |
| Tables | |
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Table 1:
Summary of all considered sources of systematic uncertainties affecting the ${M_{\mathrm{t} \mathrm{W}}}$ distributions in the 1b and 2b categories of the $\ell $+jets channel. The source of the uncertainty is given in the first column. The second column indicates if the uncertainty results in a change of normalization or the shape of the ${M_{\mathrm{t} \mathrm{W}}}$ distribution. The samples affected by a given uncertainty source are shown in the third column. The fourth column shows the impact of the uncertainty on the signal yield when changing it up or down by one standard deviation from its post-fit value, estimated for a LH ${\mathrm{b} ^{*}} $ signal with a mass of 2.4 TeV. Uncertainties taken to be fully correlated across the three years are given in the top part of the table. Uncertainties affecting both the $\ell $+jets and all-hadronic channels are marked by an asterisk ($*$). |
| Summary |
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A search for a heavy resonance decaying to tW in the final state with a lepton and a t-tagged jet was presented. Data of proton-proton collisions at a center-of-mass energy of 13 TeV corresponding to 137 fb$^{-1}$ were analyzed. The final state where the W boson decays leptonically and the top quark decays fully hadronically is probed. The HOTVR algorithm is used for the first time in an analysis of LHC data to identify the collimated top quark decay, thereby extending the reach of the analysis to masses from 0.7 to 4.2 TeV. The dominant $\mathrm{t\bar{t}}$ background is constrained using a dedicated control region and the background from misidentified t jets is estimated from data. No significant excess of data over the background prediction is observed. A statistical combination with an analysis in the all-hadronic final state is performed. The $\mathrm{b}^{*}$ hypotheses with left-handed, right-handed and vector-like chiralities are excluded at 95% confidence level up to masses of 2.95, 3.03 and 3.22 TeV, respectively. |
| References | ||||
| 1 | H. Harari | Composite models for quarks and leptons | PR 104 (1984) 159 | |
| 2 | U. Baur, M. Spira, and P. M. Zerwas | Excited-quark and -lepton production at hadron colliders | PRD 42 (1990) 815 | |
| 3 | T. M. P. Tait and C. P. Yuan | Single top quark production as a window to physics beyond the standard model | PRD 63 (2000) 014018 | hep-ph/0007298 |
| 4 | J. Nutter, R. Schwienhorst, D. G. E. Walker, and J.-H. Yu | Single top production as a probe of $ \mathrm{{B}}^{\prime} $ quarks | PRD 86 (2012) 094006 | 1207.5179 |
| 5 | CMS Collaboration | The CMS experiment at the CERN LHC | JINST 3 (2008) S08004 | CMS-00-001 |
| 6 | ATLAS Collaboration | Search for single b$^{*}$-quark production with the ATLAS detector at $ \sqrt{s}= $ 7 TeV | PLB 721 (2013) 171 | 1301.1583 |
| 7 | ATLAS Collaboration | Search for the production of single vector-like and excited quarks in the $ {\mathrm{W}}{\mathrm{t}} $ final state in pp collisions at $ \sqrt{s} = $ 8 TeV with the ATLAS detector | JHEP 02 (2016) 110 | 1510.02664 |
| 8 | CMS Collaboration | Search for the production of an excited bottom quark decaying to $ {\mathrm{t}}{\mathrm{W}} $ in proton-proton collisions at $ \sqrt{s}= $ 8 TeV | JHEP 01 (2016) 166 | CMS-B2G-14-005 1509.08141 |
| 9 | CMS Collaboration | Search for a heavy resonance decaying to a top quark and a W boson at $ \sqrt{s} = $ 13 TeV in the fully hadronic final state | CMS-PAS-B2G-19-003 | CMS-PAS-B2G-19-003 |
| 10 | A. J. Larkoski, I. Moult, and B. Nachman | Jet substructure at the Large Hadron Collider: A review of recent advances in theory and machine learning | Phys. Rep. 841 (2020) 1 | 1709.04464 |
| 11 | R. Kogler, B. Nachman, A. Schmidt (editors) et al. | Jet substructure at the Large Hadron Collider | Rev. Mod. Phys. 91 (2019) 045003 | 1803.06991 |
| 12 | T. Lapsien, R. Kogler, and J. Haller | A new tagger for hadronically decaying heavy particles at the LHC | EPJC 76 (2016) 600 | 1606.04961 |
| 13 | CMS Collaboration | The CMS trigger system | JINST 12 (2017) P01020 | CMS-TRG-12-001 1609.02366 |
| 14 | S. Frixione, P. Nason, and C. Oleari | Matching NLO QCD computations with parton shower simulations: The POWHEG method | JHEP 11 (2007) 070 | 0709.2092 |
| 15 | P. Nason | A new method for combining NLO QCD with shower Monte Carlo algorithms | JHEP 11 (2004) 040 | hep-ph/0409146 |
| 16 | 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 |
| 17 | S. Frixione, P. Nason, and G. Ridolfi | A positive-weight next-to-leading-order Monte Carlo for heavy flavour hadroproduction | JHEP 09 (2007) 126 | 0707.3088 |
| 18 | E. Re | Single-top $ {\mathrm{W}}{\mathrm{t}} $-channel production matched with parton showers using the POWHEG method | EPJC 71 (2011) 1547 | 1009.2450 |
| 19 | 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 |
| 20 | 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 |
| 21 | 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 |
| 22 | M. Aliev et al. | HATHOR -- HAdronic Top and Heavy quarks crOss section calculatoR | CPC 182 (2011) 1034 | 1007.1327 |
| 23 | 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 |
| 24 | CMS Collaboration | Measurements of $ \mathrm{t\overline{t}} $ differential cross sections in proton-proton collisions at $ \sqrt{s}= $ 13 TeV using events containing two leptons | JHEP 02 (2019) 149 | CMS-TOP-17-014 1811.06625 |
| 25 | T. Sjostrand et al. | An introduction to PYTHIA 8.2 | CPC 191 (2015) 159 | 1410.3012 |
| 26 | CMS Collaboration | Event generator tunes obtained from underlying event and multiparton scattering measurements | EPJC 76 (2016) 155 | CMS-GEN-14-001 1512.00815 |
| 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 | 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 |
| 29 | NNPDF Collaboration | Parton distributions for the LHC Run II | JHEP 04 (2015) 040 | 1410.8849 |
| 30 | NNPDF Collaboration | Parton distributions from high-precision collider data | EPJC 77 (2017) 663 | 1706.00428 |
| 31 | CMS Collaboration | Measurement of the inelastic proton-proton cross section at $ \sqrt{s}= $ 13 TeV | JHEP 07 (2018) 161 | CMS-FSQ-15-005 1802.02613 |
| 32 | GEANT4 Collaboration | GEANT4: A simulation toolkit | NIMA 506 (2003) 250 | |
| 33 | CMS Collaboration | Particle-flow reconstruction and global event description with the CMS detector | JINST 12 (2017) P10003 | CMS-PRF-14-001 1706.04965 |
| 34 | CMS Collaboration | Electron and photon reconstruction and identification with the CMS experiment at the CERN LHC | Submitted to JINST | CMS-EGM-17-001 2012.06888 |
| 35 | 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 |
| 36 | CMS Collaboration | Technical proposal for the Phase-II upgrade of the Compact Muon Solenoid | CMS-PAS-TDR-15-002 | CMS-PAS-TDR-15-002 |
| 37 | 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 |
| 38 | M. Cacciari, G. P. Salam, and G. Soyez | The anti-$ {k_{\mathrm{T}}} $ jet clustering algorithm | JHEP 04 (2008) 063 | 0802.1189 |
| 39 | M. Cacciari, G. P. Salam, and G. Soyez | FastJet user manual | EPJC 72 (2012) 1896 | 1111.6097 |
| 40 | M. Cacciari and G. P. Salam | Pileup subtraction using jet areas | PLB 659 (2008) 119 | 0707.1378 |
| 41 | Y. L. Dokshitzer, G. D. Leder, S. Moretti, and B. R. Webber | Better jet clustering algorithms | JHEP 08 (1997) 001 | hep-ph/9707323 |
| 42 | M. Wobisch and T. Wengler | Hadronization corrections to jet cross-sections in deep inelastic scattering | in Proceedings of the Workshop on Monte Carlo Generators for HERA Physics, Hamburg, Germany 1998 | hep-ph/9907280 |
| 43 | M. Stoll | Vetoed jet clustering: The mass-jump algorithm | JHEP 04 (2015) 111 | 1410.4637 |
| 44 | CMS Collaboration | Identification of heavy, energetic, hadronically decaying particles using machine-learning techniques | JINST 15 (2020) P06005 | CMS-JME-18-002 2004.08262 |
| 45 | CMS Collaboration | Pileup mitigation at CMS in 13 TeV data | JINST 15 (2020) P09018 | CMS-JME-18-001 2003.00503 |
| 46 | D. Bertolini, P. Harris, M. Low, and N. Tran | Pileup per particle identification | JHEP 10 (2014) 059 | 1407.6013 |
| 47 | 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 |
| 48 | J. Thaler and K. Van Tilburg | Identifying boosted objects with $ {N} $-subjettiness | JHEP 03 (2011) 015 | 1011.2268 |
| 49 | J. Thaler and K. Van Tilburg | Maximizing boosted top identification by minimizing $ {N} $-subjettiness | JHEP 02 (2012) 093 | 1108.2701 |
| 50 | CMS Collaboration | Performance of b tagging algorithms in proton-proton collisions at 13 TeV with Phase 1 CMS detector | CDS | |
| 51 | CMS Collaboration | Performance of missing transverse momentum reconstruction in proton-proton collisions at $ \sqrt{s} = $ 13 TeV using the CMS detector | JINST 14 (2019) P07004 | CMS-JME-17-001 1903.06078 |
| 52 | CMS Collaboration | Search for massive resonances decaying into $ {\mathrm{W}\mathrm{W}} $, $ {\mathrm{W}\mathrm{Z}} $ or $ {\mathrm{Z}\mathrm{Z}} $ bosons in proton-proton collisions at $ \sqrt{s} = $ 13 TeV | JHEP 03 (2017) 162 | CMS-B2G-16-004 1612.09159 |
| 53 | CMS Collaboration | CMS luminosity measurements for the 2016 data taking period | CMS-PAS-LUM-17-001 | CMS-PAS-LUM-17-001 |
| 54 | CMS Collaboration | CMS luminosity measurement for the 2017 data-taking period at $ \sqrt{s} = $ 13 TeV | CMS-PAS-LUM-17-004 | CMS-PAS-LUM-17-004 |
| 55 | CMS Collaboration | CMS luminosity measurement for the 2018 data-taking period at $ \sqrt{s} = $ 13 TeV | CMS-PAS-LUM-18-002 | CMS-PAS-LUM-18-002 |
| 56 | J. S. Conway | Incorporating nuisance parameters in likelihoods for multisource spectra | in Proceedings, workshop on statistical issues related to discovery claims in search experiments and unfolding (PHYSTAT 2011) | 1103.0354 |
| 57 | R. J. Barlow and C. Beeston | Fitting using finite Monte Carlo samples | CPC 77 (1993) 219 | |
| 58 | G. Cowan, K. Cranmer, E. Gross, and O. Vitells | Asymptotic formulae for likelihood-based tests of new physics | EPJC 71 (2011) 1554 | 1007.1727 |
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Compact Muon Solenoid LHC, CERN |
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