Search for Two Higgs Bosons in Final States Containing Two Photons and Two Bottom Quarks
Search for Two Higgs Bosons in Final States Containing Two Photons and Two Bottom Quarks

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Published: 2016

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A search is presented for the production of two Higgs bosons in final states containing two photons and two bottom quarks. Both resonant and nonresonant hypotheses are investigated. The analyzed data correspond to an integrated luminosity of 19.7 inverse femtobarns of proton-proton collisions at sqrt(s) = 8 TeV collected with the CMS detector. Good agreement is observed between data and predictions of the standard model (SM). Upper limits are set at 95% confidence level on the production cross section of new particles and compared to the prediction for the existence of a warped extra dimension. When the decay to two Higgs bosons is kinematically allowed, assuming a mass scale LambdaR = 1 TeV for the model, the data exclude a radion scalar at masses below 980 GeV. The first Kaluza-Klein excitation mode of the graviton in Randall-Sundrum models is excluded for masses between 325 and 450 GeV. Limits set on nonresonant production constrain the parameter space for anomalous Higgs boson couplings.

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

Published: 2018-12-06

Total Pages: 283

ISBN-13: 3030040550

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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.

Higgs boson potential at colliders: status and perspectives
Higgs boson potential at colliders: status and perspectives

Author: Biagio Di Micco

Publisher: Roma TrE-Press

Published: 2020-12-18

Total Pages: 281

ISBN-13:

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Questo documento riassume lo stato attuale degli ricerche studi, teorici e sperimentali, sulla produzione di coppie di bosoni di Higgs, e sui vincoli, sia diretti che indiretti, al valore del termine di auto-interazione del bosone di Higgs, con l’intento di servire da referenza per i prossimi anni. Il documento discute lo stato degli studi teorici, includendo le più recenti stime della sezione di produzione di coppie di bosoni di Higgs, sviluppi sulle teorie di campo efficaci, e studi su specifici scenari di nuova fisica che possono contribuire alla produzione di due bosoni di Higgs. Sono presentati i più recenti risultati sperimentali sulle ricerche di coppie di bosoni di Higgs e sui limiti diretti e indiretti al termine di auto-interazione, ottenuti al Large Hadron Collider di Ginevra, con una panoramica delle tecniche sperimentali. Infine, sono discusse le capacità dei collisionatori futuri di determinare il termine di auto-interazione del bosone di Higgs. Questo lavoro è iniziato come raccolta di contributi della conferenza “Di-Higgs ai Colliders”, che ha avuto luogo a Fermilab dal 4 al 9 settembre 2018, ma gli argomenti discussi vanno al di là di quelli presentati alla conferenza, includendo ulteriori sviluppi.

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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Published: 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 Resonant Pair Production of Higgs Bosons Decaying to Two Bottom Quark-antiquark Pairs in Proton-proton Collisions at 8 TeV.
Search for Resonant Pair Production of Higgs Bosons Decaying to Two Bottom Quark-antiquark Pairs in Proton-proton Collisions at 8 TeV.

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Published: 2015

Total Pages: 23

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A 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.