Combination of Searches for Higgs Boson Pair Production in Proton-proton Collisions at √s
Author: Albert M. Sirunyan
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Published: 2018
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Author: Albert M. Sirunyan
Publisher:
Published: 2018
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DOWNLOAD EBOOKAuthor: Patrick Bryant
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Published: 2018
Total Pages: 351
ISBN-13: 9780438756397
DOWNLOAD EBOOKA search for Higgs boson pair production in the four b-jet final state is carried out with up to 36.1/fb of LHC proton-proton collision data collected at √s = 13 TeV with the ATLAS detector in 2015 and 2016. Three benchmark signals are studied: a spin-2 graviton decaying into a Higgs boson pair, a scalar resonance decaying into a Higgs boson pair, and Standard Model non-resonant Higgs boson pair production. This thesis presents a search in events with four individually resolved b-tagged jets. Higgs bosons produced with large momenta are reconstructed as single large radius jets with substructure. The analysis of this topology is presented in CERN-THESIS-2018-118. The two analyses are statistically combined and upper limits on the production cross section of Higgs boson pairs times branching ratio to four b-quarks are set in each model. The combined result searches for resonance masses in the range 260-3000 GeV. No significant excess is observed; the largest deviation of data over prediction is found at a mass of 280 GeV, corresponding to 2.3 standard deviations globally. The observed 95% confidence level upper limit on the non-resonant production is 13 times the Standard Model prediction.
Author: Zhiyuan Li
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Published: 2022
Total Pages: 0
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DOWNLOAD EBOOKAuthor: CMS Collaboration
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Published: 2017
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DOWNLOAD EBOOKAuthor: Albert M. Sirunyan
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Published: 2020
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Published: 2017
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Published: 2015
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DOWNLOAD EBOOKA search for Higgs boson pair production \(pp \rightarrow hh\) is performed with 19.5 fb\(^{-1}\) of proton-proton collision data at \(\sqrt{s}=8\) TeV, which were recorded by the ATLAS detector at the Large Hadron Collider in 2012. The decay products of each Higgs boson are reconstructed as a high-momentum \(b\bar{b}\) system with either a pair of small-radius jets or a single large-radius jet, the latter exploiting jet substructure techniques and associated b-tagged track-jets. No evidence for resonant or non-resonant Higgs boson pair production is observed. The data are interpreted in the context of the Randall-Sundrum model with a warped extra dimension as well as the two-Higgs-doublet model. An upper limit on the cross-section for \(pp\rightarrow G^{*}_{\mathrm {KK}} \rightarrow hh \rightarrow b\bar{b}b\bar{b} \) of 3.2 (2.3) fb is set for a Kaluza-Klein graviton \(G^{*}_{\mathrm {KK}}\) mass of 1.0 (1.5) TeV, at the 95 % confidence level. The search for non-resonant Standard Model hh production sets an observed 95 % confidence level upper limit on the production cross-section \(\sigma (pp \rightarrow hh \rightarrow b\bar{b}b\bar{b})\) of 202 fb, compared to a Standard Model prediction of \(\sigma (pp \rightarrow hh \rightarrow b\bar{b}b\bar{b}) = 3.6 \pm 0.5\) fb.
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Published: 2015
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DOWNLOAD EBOOKA search for Higgs boson pair production \(pp \rightarrow hh\) is performed with 19.5 fb\(^{-1}\) of proton-proton collision data at \(\sqrt{s}=8\) TeV, which were recorded by the ATLAS detector at the Large Hadron Collider in 2012. The decay products of each Higgs boson are reconstructed as a high-momentum \(b\bar{b}\) system with either a pair of small-radius jets or a single large-radius jet, the latter exploiting jet substructure techniques and associated b-tagged track-jets. No evidence for resonant or non-resonant Higgs boson pair production is observed. The data are interpreted in the context of the Randall-Sundrum model with a warped extra dimension as well as the two-Higgs-doublet model. An upper limit on the cross-section for \(pp\rightarrow G^{*}_{\mathrm {KK}} \rightarrow hh \rightarrow b\bar{b}b\bar{b} \) of 3.2 (2.3) fb is set for a Kaluza-Klein graviton \(G^{*}_{\mathrm {KK}}\) mass of 1.0 (1.5) TeV, at the 95 % confidence level. The search for non-resonant Standard Model hh production sets an observed 95 % confidence level upper limit on the production cross-section \(\sigma (pp \rightarrow hh \rightarrow b\bar{b}b\bar{b})\) of 202 fb, compared to a Standard Model prediction of \(\sigma (pp \rightarrow hh \rightarrow b\bar{b}b\bar{b}) = 3.6 \pm 0.5\) fb.
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Published: 2016
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DOWNLOAD EBOOKA search is presented for the Higgs boson off-shell production in gluon fusion and vector boson fusion processes with the Higgs boson decaying into a WW pair and the W bosons decaying leptonically. The data observed in this analysis are used to constrain the Higgs boson total decay width. The analysis is based on the data collected by the CMS experiment at the LHC, corresponding to integrated luminosities of 4.9 inverse femtobarns at a centre-of-mass energy of 7 TeV and 19.4 inverse femtobarns at 8 TeV, respectively. An observed (expected) upper limit on the off-shell Higgs boson event yield normalised to the standard model prediction of 2.4 (6.2) is obtained at the 95% CL for the gluon fusion process and of 19.3 (34.4) for the vector boson fusion process. Observed and expected limits on the total width of 26 and 66 MeV are found, respectively, at the 95% confidence level (CL). These limits are combined with the previous result in the ZZ channel leading to observed and expected 95% CL upper limits on the width of 13 and 26 MeV, respectively.
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Published: 2015
Total Pages: 23
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DOWNLOAD EBOOKA model-independent search for a narrow resonance produced in proton-proton collisions at √s = 8 TeV and decaying to a pair of 125 GeV Higgs bosons that in turn each decays into a bottom quark-antiquark pair is performed by the CMS experiment at the LHC. We analyzed the data so that it corresponded to an integrated luminosity of 17.9 fb-1. No evidence for a signal is observed. Upper limits at a 95% confidence level on the production cross section for such a resonance, in the mass range from 270 to 1100 GeV, are reported. A radion with decay constant of 1 TeV and mass from 300 to 1100 GeV, and a Kaluza-Klein graviton with mass from 380 to 830 GeV are excluded at a 95% confidence level.