CMS-PAS-B2G-17-010 | ||
Search for heavy resonances decaying to a top and bottom quark in the lepton+jets final state in proton-proton collisions recorded by the CMS detector at 13 TeV | ||
CMS Collaboration | ||
March 2017 | ||
Abstract: A search is presented for heavy gauge bosons decaying to a top and bottom quark using data collected by the CMS experiment at √s= 13 TeV in 2016. The data set analyzed corresponds to an integrated luminosity of 35.9 fb−1. Final states that include a single lepton (e,μ), multiple jets, and missing transverse energy are analyzed. We find no evidence for the production of a W' boson, and are able to exclude at 95% confidence level the production of right-handed W' bosons with masses below 3.4 TeV if MW′R≫MνR and 3.6 TeV if MW′R<MνR at 95% confidence level. Exclusion limits for W' bosons are also presented as a function of their coupling strength to left- and right-handed fermions. The results presented are the most stringent limits published to date in the tb decay channel. | ||
Links:
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These preliminary results are superseded in this paper, PLB 777 (2017) 39. The superseded preliminary plots can be found here. |
Figures | |
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Figure 1:
The reconstructed Mtb distributions in the 1 b-tag (top) and 2 b-tag (bottom) categories, for the electron (left) and muon (right) channels, for Type A events. "LF" and "HF" indicate the light and heavy flavor components of the W+jets contribution, respectively. The simulated W′R signal and background samples are normalized to the cross section and the luminosity of the data set used. The distribution is shown after the application of all selections. The 1σ background uncertainty includes all uncertainties on the predicted background, while the σtot is the combined uncertainty on the background and data. |
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Figure 1-a:
The reconstructed Mtb distributions in the 1 b-tag category, for the electron channel, for Type A events. "LF" and "HF" indicate the light and heavy flavor components of the W+jets contribution, respectively. The simulated W′R signal and background samples are normalized to the cross section and the luminosity of the data set used. The distribution is shown after the application of all selections. The 1σ background uncertainty includes all uncertainties on the predicted background, while the σtot is the combined uncertainty on the background and data. |
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Figure 1-b:
The reconstructed Mtb distributions in the 1 b-tag category, for the muon channel, for Type A events. "LF" and "HF" indicate the light and heavy flavor components of the W+jets contribution, respectively. The simulated W′R signal and background samples are normalized to the cross section and the luminosity of the data set used. The distribution is shown after the application of all selections. The 1σ background uncertainty includes all uncertainties on the predicted background, while the σtot is the combined uncertainty on the background and data. |
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Figure 1-c:
The reconstructed Mtb distributions in the 2 b-tag category, for the electron channel, for Type A events. "LF" and "HF" indicate the light and heavy flavor components of the W+jets contribution, respectively. The simulated W′R signal and background samples are normalized to the cross section and the luminosity of the data set used. The distribution is shown after the application of all selections. The 1σ background uncertainty includes all uncertainties on the predicted background, while the σtot is the combined uncertainty on the background and data. |
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Figure 1-d:
The reconstructed Mtb distributions in the 2 b-tag category, for the muon channel, for Type A events. "LF" and "HF" indicate the light and heavy flavor components of the W+jets contribution, respectively. The simulated W′R signal and background samples are normalized to the cross section and the luminosity of the data set used. The distribution is shown after the application of all selections. The 1σ background uncertainty includes all uncertainties on the predicted background, while the σtot is the combined uncertainty on the background and data. |
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Figure 2:
The reconstructed Mtb distributions in the 1 b-tag (top) and 2 b-tag (bottom) categories, for the electron (left) and muon (right) channels, for Type B events. The simulated W′R signal and background samples are normalized to the cross section and the luminosity of the data set used. The distribution is shown after the application of all selections. The 1σ background uncertainty includes all uncertainties on the predicted background, while the σtot is the combined uncertainty on the background and data. |
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Figure 2-a:
The reconstructed Mtb distributions in the 1 b-tag category, for the electron channel, for Type B events. The simulated W′R signal and background samples are normalized to the cross section and the luminosity of the data set used. The distribution is shown after the application of all selections. The 1σ background uncertainty includes all uncertainties on the predicted background, while the σtot is the combined uncertainty on the background and data. |
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Figure 2-b:
The reconstructed Mtb distributions in the 1 b-tag category, for the muon channel, for Type B events. The simulated W′R signal and background samples are normalized to the cross section and the luminosity of the data set used. The distribution is shown after the application of all selections. The 1σ background uncertainty includes all uncertainties on the predicted background, while the σtot is the combined uncertainty on the background and data. |
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Figure 2-c:
The reconstructed Mtb distributions in the 2 b-tag category, for the electron channel, for Type B events. The simulated W′R signal and background samples are normalized to the cross section and the luminosity of the data set used. The distribution is shown after the application of all selections. The 1σ background uncertainty includes all uncertainties on the predicted background, while the σtot is the combined uncertainty on the background and data. |
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Figure 2-d:
The reconstructed Mtb distributions in the 2 b-tag category, for the muon channel, for Type B events. The simulated W′R signal and background samples are normalized to the cross section and the luminosity of the data set used. The distribution is shown after the application of all selections. The 1σ background uncertainty includes all uncertainties on the predicted background, while the σtot is the combined uncertainty on the background and data. |
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Figure 3:
95% C.L. upper limit on the W' boson production cross section separately in the electron (top) and muon (bottom) channels for right-handed W'. W' boson masses for which the theoretical cross section (in red and/or blue) exceeds the observed upper limit (in solid black) are excluded at 95% C.L. The green and yellow bands represent the ± 1 and 2 standard deviation uncertainties on the expected limit, respectively. |
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Figure 3-a:
95% C.L. upper limit on the W' boson production cross section separately in the electron channel for right-handed W'. W' boson masses for which the theoretical cross section (in red and/or blue) exceeds the observed upper limit (in solid black) are excluded at 95% C.L. The green and yellow bands represent the ± 1 and 2 standard deviation uncertainties on the expected limit, respectively. |
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Figure 3-b:
95% C.L. upper limit on the W' boson production cross section separately in the muon channel for right-handed W'. W' boson masses for which the theoretical cross section (in red and/or blue) exceeds the observed upper limit (in solid black) are excluded at 95% C.L. The green and yellow bands represent the ± 1 and 2 standard deviation uncertainties on the expected limit, respectively. |
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Figure 4:
95% C.L. upper limit on the W' boson production cross section for right-handed W'. W' boson masses for which the theoretical cross section (in red and/or blue) exceeds the observed upper limit (in solid black) are excluded at 95% C.L. The green and yellow bands represent the ±1 and 2 standard deviation uncertainties on the expected limit, respectively. |
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Figure 5:
Expected (left) and observed (right) limits on the W' signal mass as function of the left-handed (aL) and right-handed (aR) couplings. Black lines represent contours of equal mass. |
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Figure 5-a:
Expected limit on the W' signal mass as function of the left-handed (aL) and right-handed (aR) couplings. Black lines represent contours of equal mass. |
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Figure 5-b:
Observed limit on the W' signal mass as function of the left-handed (aL) and right-handed (aR) couplings. Black lines represent contours of equal mass. |
Tables | |
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Table 1:
Observed event yield and expected event yield from all background processes and three different signal masses. Yields are separated into 8 event categories by lepton type (e or μ), number of b-tags (1 or 2), and ptopT and pj1+j2T (Type A or Type B). The uncertainty on the total expected background includes both systematic and statistical sources. |
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Table 2:
List of systematic uncertainties taken into account in the analysis. For sources which affect the shape of the M(tb) distribution the rate uncertainty given is approximate. The Pileup, Top pT Reweighting, and W+jets Heavy/Light Flavor systematic uncertainties are described in more detail in the text. A checkmark in the "Signal" column indicates that the uncertainty is also applied to signal samples. (*)For signal samples only the shape component of the uncertainty due to parton distribution functions is included. |
Summary |
We have performed a search for a heavy W' boson resonance decaying to a top and a bottom quark in lepton + jets final states in data collected at √s= 13 TeV by the CMS detector in 2016. The integrated luminosity of the data set analyzed is 35.9 fb−1. We observe no evidence for the production of a W' boson, and 95% upper limits on σ(pp→W'R)×B(W'R→tb) are determined as a function of the W′R boson mass. The observed (expected) 95% confidence level upper limit is 3.4 (3.3) TeV if MW′R≫MνR and 3.6 (3.5) TeV if $M_{W'_{\mathrm{R}}} |
References | ||||
1 | M. Schmaltz and D. Tucker-Smith | LITTLE HIGGS THEORIES | Annual Review of Nuclear and Particle Science 55 (2005), no. 1, 229 | |
2 | T. Appelquist, H.-C. Cheng, and B. A. Dobrescu | Bounds on universal extra dimensions | PRD 64 (2001) 035002 | |
3 | H.-C. Cheng, C. T. Hill, S. Pokorski, and J. Wang | Standard model in the latticized bulk | PRD 64 (2001) 065007 | |
4 | R. S. Chivukula, E. H. Simmons, and J. Terning | Limits on noncommuting extended technicolor | PRD 53 (1996) 5258 | |
5 | R. N. Mohapatra and J. C. Pati | Left-right gauge symmetry and an 'isoconjugate' model of CP violation | PRD 11 (1975) 566 | |
6 | D. J. Muller and S. Nandi | Topflavor: a separate SU(2) for the third family | PLB 383 (1996), no. 3, 345 | |
7 | E. Malkawi, T. Tait, and C.-P. Yuan | A model of strong flavor dynamics for the top quark | PLB 385 (1996), no. 1, 304 | |
8 | D0 Collaboration | Search for W' Boson Resonances Decaying to a Top Quark and a Bottom Quark | PRL 100 (2008) 211803 | |
9 | D0 Collaboration | Search for W' resonances with left- and right-handed couplings to fermions | PLB 699 (2011), no. 3, 145 | |
10 | CDF Collaboration | Search for Resonances Decaying to Top and Bottom Quarks with the CDF Experiment | PRL 115 (Aug, 2015) 061801 | |
11 | CMS Collaboration | Search for W' → tb decays in the lepton + jets final state in pp collisions at √s= 8 TeV | JHEP 05 (2014) 108 | CMS-B2G-12-010 1402.2176 |
12 | CMS Collaboration | Search for W' → tb decays in proton-proton collisions at √s= 8 TeV | JHEP 02 (2016) 122 | CMS-B2G-12-009 1509.06051 |
13 | CMS Collaboration | Search for W' boson resonances decaying into a top quark and a bottom quark in the leptonic final state at √s= 13 TeV | CMS-PAS-B2G-15-004 | CMS-PAS-B2G-15-004 |
14 | CMS Collaboration | Search for W' boson resonances decaying into a top quark and a bottom quark in the leptonic final state using data collected at √s= 13 TeV | CMS-PAS-B2G-16-017 | CMS-PAS-B2G-16-017 |
15 | ATLAS Collaboration | Search for W' →tˉb in the lepton plus jets final state in proton-proton collisions at a centre-of-mass energy of √s= 8 TeV with the ATLAS detector | PLB 743 (2015) 235 | 1410.4103 |
16 | ATLAS Collaboration | Search for W′→tb→qqbb decays in pp collisions at √s= 8 TeV with the ATLAS detector | EPJC75 (2015), no. 4, 165 | 1408.0886 |
17 | CMS Collaboration | The CMS experiment at the CERN LHC | JINST 3 (2008) S08004 | CMS-00-001 |
18 | CMS Collaboration | Performance of photon reconstruction and identification with the CMS detector in proton-proton collisions at √s= 8 TeV | JINST 10 (2015) P08010 | CMS-EGM-14-001 1502.02702 |
19 | CMS Collaboration Collaboration | Determination of jet energy calibration and transverse momentum resolution in CMS | JINST 6 (2011) P11002 | 1107.4277 |
20 | CMS Collaboration | Performance of electron reconstruction and selection with the CMS detector in proton-proton collisions at √s= 8 TeV | JINST 10 (2015) P06005 | CMS-EGM-13-001 1502.02701 |
21 | CMS Collaboration | Performance of CMS muon reconstruction in pp collision events at √s=7TeV | JINST 7 (2012) P10002 | CMS-MUO-10-004 1206.4071 |
22 | CMS Collaboration | Particle-flow event reconstruction in CMS and performance for jets, taus, and EmissT | CDS | |
23 | CMS Collaboration | Commissioning of the particle-flow event reconstruction with the first LHC collisions recorded in the CMS detector | CDS | |
24 | CompHEP Collaboration | CompHEP 4.4: Automatic computations from Lagrangians to events | NIMA534 (2004) 250 | hep-ph/0403113 |
25 | Z. Sullivan | Fully differential W′ production and decay at next-to-leading order in QCD | PRD 66 (2002) 075011 | hep-ph/0207290 |
26 | D. Duffty and Z. Sullivan | Model independent reach for W-prime bosons at the LHC | PRD 86 (2012) 075018 | 1208.4858 |
27 | 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 |
28 | S. Frixione, P. Nason, and C. Oleari | Matching NLO QCD computations with Parton Shower simulations: the POWHEG method | JHEP 11 (2007) 070 | |
29 | S. M. T. Sjostrand and P. Z. Skands | PYTHIA 6.4 Physics and Manual | JHEP 0605 (2006) | |
30 | CMS Collaboration Collaboration | Measurement of particle level differential ttbar cross sections in the dilepton channel at sqrt(s) = 13 TeV | Technical Report CMS-PAS-TOP-16-007, CERN, Geneva | |
31 | CMS Collaboration Collaboration | Measurement of differential cross sections for top quark pair production using the lepton+jets final state in proton-proton collisions at 13 TeV | Technical Report CERN-EP-2016-227. CMS-TOP-16-008, CERN, Geneva, Oct, 2016 Submitted to PRD | |
32 | S. J. Allison et al. | GEANT | IEEE Trans. Nucl. Sci. 53 (2006) 270 | |
33 | NNPDF Collaboration | Parton distributions for the LHC Run II | JHEP 04 (2015) 040 | 1410.8849 |
34 | J. Butterworth et al. | PDF4LHC recommendations for LHC Run II | JPG43 (2016) 023001 | 1510.03865 |
35 | CMS Collaboration | Commissioning of the particle-flow event reconstruction with leptons from J/ψ and W decays at 7 TeV | CDS | |
36 | M. Cacciari, G. P. Salam, and G. Soyez | The anti-kt jet clustering algorithm | JHEP 04 (2008) 063 | 0802.1189 |
37 | M. Cacciari, G. P. Salam, and G. Soyez | FastJet user manual | EPJC 72 (2012) 1896 | 1111.6097 |
38 | CMS Collaboration | Determination of Jet Energy Calibration and Transverse Momentum Resolution in CMS | JINST 6 (2011) P11002 | CMS-JME-10-011 1107.4277 |
39 | D. Krohn, M. D. Schwartz, M. Low, and L.-T. Wang | Jet Cleansing: Pileup Removal at High Luminosity | PRD90 (2014), no. 6, 065020 | 1309.4777 |
40 | M. Cacciari and G. P. Salam | Pileup subtraction using jet areas | PLB 659 (2008) 119 | 0707.1378 |
41 | CMS Collaboration | Measurement of the tˉt Production Cross Section in pp Collisions at 7 TeV in Lepton + Jets Events Using b-quark Jet Identification | PRD84 (2011) 092004 | CMS-TOP-10-003 1108.3773 |
42 | M. Cacciari et al. | The t anti-t cross-section at 1.8-TeV and 1.96-TeV: A Study of the systematics due to parton densities and scale dependence | JHEP 04 (2004) 068 | hep-ph/0303085 |
43 | S. Catani, D. de Florian, M. Grazzini, and P. Nason | Soft gluon resummation for Higgs boson production at hadron colliders | JHEP 07 (2003) 028 | hep-ph/0306211 |
44 | T. Muller, J. Ott, and J. Wagner-Kuhr | theta - a framework for template-based modeling and inference | ||
45 | R. Barlow and C. Beeston | Fitting using finite Monte Carlo samples | Computer Physics Communications 77 (1993), no. 2, 219 |
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Compact Muon Solenoid LHC, CERN |
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