Combined Results of Searches for the Standard Model Higgs Boson in Pp Collisions at Sqrt(s)

Combined Results of Searches for the Standard Model Higgs Boson in Pp Collisions at Sqrt(s)
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Release: 2012
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Combined results are reported from searches for the standard model Higgs boson in proton-proton collisions at sqrt(s)=7 TeV in five Higgs boson decay modes: gamma pair, b-quark pair, tau lepton pair, W pair, and Z pair. The explored Higgs boson mass range is 110-600 GeV. The analysed data correspond to an integrated luminosity of 4.6-4.8 inverse femtobarns. The expected excluded mass range in the absence of the standard model Higgs boson is 118-543 GeV at 95% CL. The observed results exclude the standard model Higgs boson in the mass range 127-600 GeV at 95% CL, and in the mass range 129-525 GeV at 99% CL. An excess of events above the expected standard model background is observed at the low end of the explored mass range making the observed limits weaker than expected in the absence of a signal. The largest excess, with a local significance of 3.1 sigma, is observed for a Higgs boson mass hypothesis of 124 GeV. The global significance of observing an excess with a local significance greater than 3.1 sigma anywhere in the search range 110-600 (110-145) GeV is estimated to be 1.5 sigma (2.1 sigma). More data are required to ascertain the origin of this excess.

Search for the Standard Model Higgs Boson Decaying Into Two Photons in Pp Collisions at Sqrt(s)

Search for the Standard Model Higgs Boson Decaying Into Two Photons in Pp Collisions at Sqrt(s)
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Release: 2012
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A search for a Higgs boson decaying into two photons is described. The analysis is performed using a dataset recorded by the CMS experiment at the LHC from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross section of the standard model Higgs boson decaying to two photons. The expected exclusion limit at 95% confidence level is between 1.4 and 2.4 times the standard model cross section in the mass range between 110 and 150 GeV. The analysis of the data excludes, at 95% confidence level, the standard model Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The largest excess of events above the expected standard model background is observed for a Higgs boson mass hypothesis of 124 GeV with a local significance of 3.1 sigma. The global significance of observing an excess with a local significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is estimated to be 1.8 sigma. More data are required to ascertain the origin of this excess.

Search for the Standard Model Higgs Boson Decaying to a $W$ Pair in the Fully Leptonic Final State in $pp$ Collisions at $\sqrt{s}

Search for the Standard Model Higgs Boson Decaying to a $W$ Pair in the Fully Leptonic Final State in $pp$ Collisions at $\sqrt{s}
Author:
Publisher:
Total Pages: 113
Release: 2012
Genre:
ISBN:

A search for the standard model Higgs boson decaying to W+W- in pp collisions at sqrt(s) = 7 TeV is reported. The data are collected at the LHC with the CMS detector, and correspond to an integrated luminosity of 4.6 inverse femtobarns. The W+W- candidates are selected in events with two charged leptons and large missing transverse energy. No significant excess of events above the standard model background expectations is observed, and upper limits on the Higgs boson production relative to the standard model Higgs expectation are derived. The standard model Higgs boson is excluded in the mass range 129-270 GeV at 95% confidence level.

Search for Neutral Minimal Supersymmetric Standard Model Higgs Bosons Decaying to Tau Pairs in Pp Collisions at Sqrt[s]

Search for Neutral Minimal Supersymmetric Standard Model Higgs Bosons Decaying to Tau Pairs in Pp Collisions at Sqrt[s]
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Release: 2011
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A search for neutral MSSM Higgs bosons in pp collisions at the LHC at a center-of-mass energy of 7 TeV is presented. The results are based on a data sample corresponding to an integrated luminosity of 36 inverse picobarns recorded by the CMS experiment. The search uses decays of the Higgs bosons to tau pairs. No excess is observed in the tau-pair invariant-mass spectrum. The resulting upper limits on the Higgs boson production cross section times branching fraction to tau pairs, as a function of the pseudoscalar Higgs boson mass, yield stringent new bounds in the MSSM parameter space.

Searches for Invisible Decays of the Higgs Boson in Pp Collisions at $\sqrt{s}$

Searches for Invisible Decays of the Higgs Boson in Pp Collisions at $\sqrt{s}$
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Release: 2016
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Searches for invisible decays of the Higgs boson are presented. The data collected with the CMS detector at the LHC correspond to integrated luminosities of 5.1, 19.7, and 2.3 inverse femtobarns at centre-of-mass energies of 7, 8, and 13 TeV, respectively. The search channels target Higgs boson production via gluon fusion, vector boson fusion, and in association with a vector boson. Upper limits are placed on the branching fraction of the Higgs boson decay to invisible particles, as a function of the assumed production cross sections. The combination of all channels, assuming standard model production, yields an observed (expected) upper limit on the invisible branching fraction of 0.24 (0.23) at the 95% confidence level. The results are also interpreted in the context of Higgs-portal dark matter models.

Search for a Higgs Boson in the Decay Channel $H$ to ZZ(*) to $q$ Qbar $\ell-̂$ L+ in $pp$ Collisions at $\sqrt{s}

Search for a Higgs Boson in the Decay Channel $H$ to ZZ(*) to $q$ Qbar $\ell-̂$ L+ in $pp$ Collisions at $\sqrt{s}
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Release: 2012
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A search for the standard model Higgs boson decaying into two Z bosons with subsequent decay into a final state containing two quark jets and two leptons, H to ZZ(*) to q q-bar l-l+ is presented. Results are based on data corresponding to an integrated luminosity of 4.6 inverse femtobarns of proton-proton collisions at sqrt(s)=7 TeV, collected with the CMS detector at the LHC. In order to discriminate between signal and background events, kinematic and topological quantities, including the angular spin correlations of the decay products, are employed. Events are further classified according to the probability of the jets to originate from quarks of light or heavy flavor or from gluons. No evidence for the Higgs boson is found, and upper limits on its production cross section are determined for a Higgs boson of mass between 130 and 600 GeV.

Search for Higgs Boson Pair Production in the bb̅ τ+ τ- Decay Channel

Search for Higgs Boson Pair Production in the bb̅ τ+ τ- Decay Channel
Author: Luca Cadamuro
Publisher: Springer
Total Pages: 273
Release: 2018-12-06
Genre: Science
ISBN: 3030040550

This thesis presents innovative contributions to the CMS experiment in the new trigger system for the restart of the LHC collisions in Run II, as well as original analysis methods and important results that led to official publications of the Collaboration. The author's novel reconstruction algorithms, deployed on the Field-Programmable Gate Arrays of the new CMS trigger architecture, have brought a gain of over a factor 2 in efficiency for the identification of tau leptons, with a very significant impact on important H boson measurements, such as its decays to tau lepton pairs and the search for H boson pair production. He also describes a novel analysis of HH → bb tautau, a high priority physics topic in a difficult channel. The original strategy, optimisation of event categories, and the control of the background have made the result one of the most sensitive concerning the self-coupling of the Higgs boson among all possible channels at the LHC.

Searches for Beyond Standard Model Higgs Bosons in Pp Collisions at [square Root Of] S

Searches for Beyond Standard Model Higgs Bosons in Pp Collisions at [square Root Of] S
Author: Pedro H. Sales de Bruin
Publisher:
Total Pages: 143
Release: 2016
Genre: Higgs bosons
ISBN:

The searches for a Beyond Standard Model (BSM) heavy CP-odd Higgs boson A decaying to Zh in the context of two-Higgs-doublet models (2HDM), and Minimal Supersymmetric Standard Model (MSSM) neutral Higgs bosons H/A decaying to a tau pair are presented. The search for the heavy CP-odd Higgs boson, A, is conducted through the A -> Zh -> ll T[subscript]lep T[subscript]had decay channel using 20.3 fb−1 of proton-proton collision data collected by the ATLAS detector at a center-of-mass of 8 TeV. The search for the neutral MSSM H/A decaying to a tau pair in the T[subscript]lep T[subscript]had b-veto final state is done using 3.2 fb−1 of proton-proton collision data recorded by the ATLAS detector at a center-of-mass of 13 TeV. The observed data agrees with the Standard Model background prediction, and upper limits are set on cross-section times branching ratio of neutral BSM Higgs bosons.