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| CMS-PAS-B2G-17-009 | ||
| Search for a singly produced vector-like quark B decaying to a b quark and a Higgs boson in a fully hadronic final state using boosted topologies | ||
| CMS Collaboration | ||
| July 2017 | ||
| Abstract: A search is presented for the single production of a heavy vector-like quark (B) decaying to a Higgs boson and a bottom quark, $\mathrm{B}\rightarrow\mathrm{H}\mathrm{b}$, with the Higgs boson decaying to a pair of bottom quarks. The decay products of the Higgs boson are highly boosted, hence typically collimated. They are reconstructed as a single, massive jet, with heavy flavour content. The single production of vector-like quarks is characterised by the presence of a light flavour quark emitted in the forward region of the detector. The analysis is performed using a data sample collected in 2016 by the CMS experiment at the LHC in proton-proton collisions at a centre-of-mass energy of $\sqrt{s}= $ 13 TeV, corresponding to an integrated luminosity of 35.9 fb$^{-1}$. The observation is consistent with background expectation and upper limits are placed on the production cross section times the branching ratio of a vector-like quark B decaying to a Higgs boson and a bottom quark. Values of cross section times branching ratio above 0.07-1.28 pb are excluded at 95% confidence level for masses of 700-1800 GeV, assuming a resonance with negligible width with respect to experimental resolution. Similar sensitivity is observed for different assumptions on the intrinsic width of the vector-like quark B. | ||
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CDS record (PDF) ;
inSPIRE record ;
HepData record ;
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These preliminary results are superseded in this paper, JHEP 06 (2018) 031. The superseded preliminary plots can be found here. |
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| Figures | |
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Figure 1:
Leading order Feynman diagram for the production of a single vector-like quark B in association with a b quark, and its decay to an H boson and ab quark. |
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Figure 2:
B tagged subjet multiplicity of large radius jets after the preselection and the low hadronic activity requirement are applied. The lower panel shows the data to background ratio. Signal distributions are multiplied by a factor of 1000. Background simulated events are normalised to data. The uncertainties on the background prediction and on data are statistical only. |
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Figure 3:
Forward jet multiplicity distribution before the event categorization is performed. Signal distributions are multiplied by a factor of 1000. Background simulated events are normalised to data. The lower panel shows the simulated background to data ratio. The uncertainties in the background prediction and on data are statistical only. |
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Figure 4:
Pre-fit distributions of the reconstructed B quark mass in the categories with zero forward jets (left ) and at least one forward jet (right ) for the low (top) and high (bottom) mass analyses. The shaded error band in the ratio plot shows both statistical and systematics uncertainties. |
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Figure 4-a:
Pre-fit distributions of the reconstructed B quark mass in the categories with zero forward jet for the low mass analysis. The shaded error band in the ratio plot shows both statistical and systematics uncertainties. |
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Figure 4-b:
Pre-fit distributions of the reconstructed B quark mass in the categories with at least one forward jet for the low mass analysis. The shaded error band in the ratio plot shows both statistical and systematics uncertainties. |
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Figure 4-c:
Pre-fit distributions of the reconstructed B quark mass in the categories with zero forward jet for the high mass analysis. The shaded error band in the ratio plot shows both statistical and systematics uncertainties. |
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Figure 4-d:
Pre-fit distributions of the reconstructed B quark mass in the categories with at least one forward jet for the high mass analysis. The shaded error band in the ratio plot shows both statistical and systematics uncertainties. |
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Figure 5:
Post-fit distributions of the reconstructed B quark mass in the categories with zero forward jets (left ) and at least one forward jet (right ) for the low (top) and high (bottom) mass analyses. The shaded error band in the ratio plot shows both statistical and systematics uncertainties. |
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Figure 5-a:
Post-fit distributions of the reconstructed B quark mass in the categories with zero jet for the low mass analysis. The shaded error band in the ratio plot shows both statistical and systematics uncertainties. |
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Figure 5-b:
Post-fit distributions of the reconstructed B quark mass in the categories with at least one forward jet for the low mass analysis. The shaded error band in the ratio plot shows both statistical and systematics uncertainties. |
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Figure 5-c:
Post-fit distributions of the reconstructed B quark mass in the categories with zero jet for the high mass analysis. The shaded error band in the ratio plot shows both statistical and systematics uncertainties. |
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Figure 5-d:
Post-fit distributions of the reconstructed B quark mass in the categories with at least one forward jet for the high mass analysis. The shaded error band in the ratio plot shows both statistical and systematics uncertainties. |
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Figure 6:
Observed and expected 95% confidence level upper limit on the B quark production cross section times branching fraction as a function of the signal mass hypothesis, under the assumption of narrow width resonance, for the combination of zero and at least one forward jet categories, assuming that the coupling coefficient c(bZ)=0.5 and $\mathcal {B}$(B $\rightarrow $Hb)=0.25. The red solid curve corresponds to the theoretical cross section. |
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Figure 7:
Observed and expected 95% confidence level upper limit on the B quark production cross section times branching fraction as a function of the signal mass hypothesis, where a width of 10% (left), 20% (center) and 30% (right) of the resonance mass is considered for the B quark. The results are shown for the combination of zero and at least one forward jet categories. |
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Figure 7-a:
Observed and expected 95% confidence level upper limit on the B quark production cross section times branching fraction as a function of the signal mass hypothesis, where a width of 10% (left), 20% (center) and 30% (right) of the resonance mass is considered for the B quark. The results are shown for the combination of zero and at least one forward jet categories. |
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Figure 7-b:
Observed and expected 95% confidence level upper limit on the B quark production cross section times branching fraction as a function of the signal mass hypothesis, where a width of 10% (left), 20% (center) and 30% (right) of the resonance mass is considered for the B quark. The results are shown for the combination of zero and at least one forward jet categories. |
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Figure 7-c:
Observed and expected 95% confidence level upper limit on the B quark production cross section times branching fraction as a function of the signal mass hypothesis, where a width of 10% (left), 20% (center) and 30% (right) of the resonance mass is considered for the B quark. The results are shown for the combination of zero and at least one forward jet categories. |
| Tables | |
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Table 1:
Observed and expected event yields in the signal region in both low mass and high mass ranges. The multijet background expectation yields are derived from data, while the yields for the other sources of background are derived from simulation. |
| Summary |
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A search for electroweak production of a B quark with charge $-1/3e$, decaying to a b quark and a Higgs boson is presented. The analysis uses 35.9 fb$^{-1}$ of proton-proton collision data collected in 2016 by the CMS experiment at $\sqrt{s} = $ 13 TeV. No significant deviations from SM expectations are observed and upper limits are set on the production cross section of a B quark. Expected (observed) limits vary between 0.07 (0.07) pb and 1.20 (1.28) pb at 95% confidence level, for the range of resonance mass considered. The search has been performed under the hypothesis of a singlet B quark decaying to Hb with branching ratio equal to 25% and narrow width resonance. The hypothesis of non-negligible width has also been studied, by considering production of a B quark with an intrinsic width of 10%, 20% and 30% of the resonance mass. |
| References | ||||
| 1 | ATLAS Collaboration | Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC | PLB 716 (2012) 1--29 | 1207.7214 |
| 2 | CMS Collaboration | Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC | PLB 716 (2012) 30--61 | CMS-HIG-12-028 1207.7235 |
| 3 | J. A. Aguilar-Saavedra, R. Benbrik, S. Heinemeyer, and M. Parez-Victoria | Handbook of vectorlike quarks: Mixing and single production | PRD88 (2013), no. 9, 094010 | 1306.0572 |
| 4 | O. Matsedonskyi, G. Panico, and A. Wulzer | Light Top Partners for a Light Composite Higgs | JHEP 01 (2013) 164 | 1204.6333 |
| 5 | M. Perelstein, M. E. Peskin, and A. Pierce | Top quarks and electroweak symmetry breaking in little Higgs models | PRD69 (2004) 075002 | hep-ph/0310039 |
| 6 | R. Contino, L. Da Rold, and A. Pomarol | Light custodians in natural composite Higgs models | PRD75 (2007) 055014 | hep-ph/0612048 |
| 7 | R. Contino, T. Kramer, M. Son, and R. Sundrum | Warped/composite phenomenology simplified | JHEP 05 (2007) 074 | hep-ph/0612180 |
| 8 | J. A. Aguilar-Saavedra | Identifying top partners at LHC | JHEP 11 (2009) 030 | 0907.3155 |
| 9 | A. De Simone, O. Matsedonskyi, R. Rattazzi, and A. Wulzer | A First Top Partner Hunter's Guide | JHEP 04 (2013) 004 | 1211.5663 |
| 10 | M. Buchkremer, G. Cacciapaglia, A. Deandrea, and L. Panizzi | Model Independent Framework for Searches of Top Partners | Nucl. Phys. B876 (2013) 376--417 | 1305.4172 |
| 11 | O. Eberhardt et al. | Joint analysis of Higgs decays and electroweak precision observables in the Standard Model with a sequential fourth generation | PRD86 (2012) 013011 | 1204.3872 |
| 12 | G. D. Kribs, T. Plehn, M. Spannowsky, and T. M. P. Tait | Four generations and Higgs physics | PRD 76 (2007) 075016 | 0706.3718 |
| 13 | ATLAS Collaboration | Search for vector-like $ B $ quarks in events with one isolated lepton, missing transverse momentum and jets at $ \sqrt{s}= $ 8 TeV with the ATLAS detector | PRD91 (2015), no. 11, 112011 | 1503.05425 |
| 14 | ATLAS Collaboration | Search for pair production of a new heavy quark that decays into a $ W $ boson and a light quark in $ pp $ collisions at $ \sqrt{s} = $ 8 TeV with the ATLAS detector | PRD92 (2015), no. 11, 112007 | 1509.04261 |
| 15 | ATLAS Collaboration | Search for pair and single production of new heavy quarks that decay to a $ Z $ boson and a third-generation quark in $ pp $ collisions at $ \sqrt{s}=$ 8 TeV with the ATLAS detector | JHEP 11 (2014) 104 | 1409.5500 |
| 16 | ATLAS Collaboration | Search for single production of a vector-like quark via a heavy gluon in the $ 4b $ final state with the ATLAS detector in $ pp $ collisions at $ \sqrt{s} = $ 8 TeV | PLB758 (2016) 249--268 | 1602.06034 |
| 17 | ATLAS Collaboration | Search for single production of a vector-like quark via a heavy gluon in the $ 4b $ final state with the ATLAS detector in $ pp $ collisions at $ \sqrt{s} = $ 8 TeV | PLB758 (2016) 249--268 | 1602.06034 |
| 18 | ATLAS Collaboration | Search for single production of vector-like quarks decaying into Wb in pp collisions at $ \sqrt{s} = $ 8 TeV with the ATLAS detector | EPJC76 (2016), no. 8, 442 | 1602.05606 |
| 19 | ATLAS Collaboration | Search for the production of single vector-like and excited quarks in the $ Wt $ final state in $ pp $ collisions at $ \sqrt{s} = $ 8 TeV with the ATLAS detector | JHEP 02 (2016) 110 | 1510.02664 |
| 20 | CMS Collaboration | Search for vector-like charge 2/3 T quarks in proton-proton collisions at sqrt(s) = 8 TeV | PRD93 (2016), no. 1, 012003 | CMS-B2G-13-005 1509.04177 |
| 21 | CMS Collaboration | Search for pair-produced vectorlike B quarks in proton-proton collisions at $ \sqrt{s} =$ 8 TeV | PRD93 (2016), no. 11, 112009 | CMS-B2G-13-006 1507.07129 |
| 22 | CMS Collaboration | Search for top-quark partners with charge 5/3 in the same-sign dilepton final state | PRL 112 (2014), no. 17, 171801 | CMS-B2G-12-012 1312.2391 |
| 23 | CMS Collaboration | Search for single production of vector-like quarks decaying to a Z boson and a top or a bottom quark in proton-proton collisions at $ \sqrt{s}=$ 13 TeV | JHEP 05 (2017) 029 | CMS-B2G-16-001 1701.07409 |
| 24 | CMS Collaboration | Search for single production of a heavy vector-like T quark decaying to a Higgs boson and a top quark with a lepton and jets in the final state | PLB771 (2017) 80--105 | CMS-B2G-15-008 1612.00999 |
| 25 | CMS Collaboration | Search for single production of vector-like quarks decaying to a Z boson and a top or a bottom quark in proton-proton collisions at $ \sqrt{s}=$ 13 TeV | JHEP 05 (2017) 029 | CMS-B2G-16-001 1701.07409 |
| 26 | CMS Collaboration | Search for electroweak production of a vector-like quark decaying to a top quark and a Higgs boson using boosted topologies in fully hadronic final states | JHEP 04 (2017) 136 | CMS-B2G-16-005 1612.05336 |
| 27 | CMS Collaboration | Search for single production of vector-like quarks decaying into a b quark and a W boson in proton-proton collisions at $ \sqrt{s} = $ 13 TeV | CMS-B2G-16-006 1701.08328 |
|
| 28 | CMS Collaboration | The CMS Experiment at the CERN LHC | JINST 3 (2008) S08004 | CMS-00-001 |
| 29 | CMS Collaboration | The CMS trigger system | JINST 12 (2017) P01020 | CMS-TRG-12-001 1609.02366 |
| 30 | CMS Collaboration | Particle-flow reconstruction and global event description with the CMS detector | Submitted to JINST | CMS-PRF-14-001 1706.04965 |
| 31 | M. Cacciari, G. P. Salam, and G. Soyez | The anti-$ k_t $ jet clustering algorithm | JHEP 04 (2008) 063 | 0802.1189 |
| 32 | CMS Collaboration | Pileup Removal Algorithms | CMS-PAS-JME-14-001 | CMS-PAS-JME-14-001 |
| 33 | M. Cacciari, G. P. Salam, and G. Soyez | FastJet user manual | EPJC 72 (2012) 1896 | 1111.6097 |
| 34 | CMS Collaboration | Jet algorithms performance in 13 TeV data | CMS-PAS-JME-16-003 | CMS-PAS-JME-16-003 |
| 35 | CMS Collaboration | Identification of b quark jets at the CMS Experiment in the LHC Run 2 | CMS-PAS-BTV-15-001 | CMS-PAS-BTV-15-001 |
| 36 | S. D. Ellis, C. K. Vermilion, and J. R. Walsh | Techniques for improved heavy particle searches with jet substructure | PRD80 (2009) 051501 | 0903.5081 |
| 37 | A. J. Larkoski, S. Marzani, G. Soyez, and J. Thaler | Soft Drop | JHEP 05 (2014) 146 | 1402.2657 |
| 38 | 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 1407 (2014) 079 | 1405.0301 |
| 39 | T. Sjöstrand et al. | An Introduction to PYTHIA 8.2 | CPC 191 (2015) 159--177 | 1410.3012 |
| 40 | P. Nason | A New method for combining NLO QCD with shower Monte Carlo algorithms | JHEP 0411 (2004) 040 | hep-ph/0409146 |
| 41 | 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 |
| 42 | S. Frixione, P. Nason, and C. Oleari | Matching NLO QCD computations with Parton Shower simulations: the POWHEG method | JHEP 11 (2007) 070 | 0709.2092 |
| 43 | 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 |
| 44 | M. Czakon and A. Mitov | Top++: A program for the calculation of the top-pair cross-section at hadron colliders | Computer Physics Communications 185 (2014) 11 | |
| 45 | Y. Li and F. Petriello | Combining QCD and electroweak corrections to dilepton production in FEWZ | PRD86 (2012) 094034 | 1208.5967 |
| 46 | O. Matsedonskyi, G. Panico, and A. Wulzer | On the Interpretation of Top Partners Searches | JHEP 12 (2014) 097 | 1409.0100 |
| 47 | NNPDF Collaboration | Parton distributions from high-precision collider data | 1706.00428 | |
| 48 | S. Agostinelli et al. | Geant4—a simulation toolkit | NIM A 506 (2003) 3 | |
| 49 | A. L. Read | Presentation of search results: the CLs technique | Journal of Physics G: Nuclear and Particle Physics 28 (2002), no. 10 | |
| 50 | T. Junk | Confidence level computation for combining searches with small statistics | NIMA 434 (1999) 435--443 | hep-ex/9902006 |
| 51 | G. Cowan, K. Cranmer, E. Gross, and O. Vitells | Asymptotic formulae for likelihood-based tests of new physics | EPJC 71 (2011) 1554, , [Erratum: Eur. Phys. J.C73,2501(2013)] | 1007.1727 |
| 52 | J. S. Conway | Incorporating Nuisance Parameters in Likelihoods for Multisource Spectra | in Proceedings, PHYSTAT 2011 Workshop on Statistical Issues Related to Discovery Claims in Search Experiments and Unfolding, CERN,Geneva 2011 | 1103.0354 |
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