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Gozzelino, Andrea (2014) Search for heavy lepton partners of neutrinos in the context of type III seesaw mechanism in 2012 LHC CMS data. [Tesi di dottorato]

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Abstract (inglese)

In the thesis the analysis performed for the search for see saw mechanism with heavy fermion weak triplets mediators (type III) is presented. The search is based on the process of see saw mediators via virtual charged boson with the subsequent decay in real vector boson and standard charged leptons. The considered final states host exactly three charged standard leptons and missing transverse energy, which displays indirectly standard neutrinos, and jets. The investigated electric charge sum of three leptons has unit value, both signs. The analysed data sample has been recorded by the Compact Muon Solenoid (CMS) experiment at the CERN Large Hadron Collider (LHC) in Geneva, Switzerland, during the 2012 proton-proton collisions data-taking period. The data sample consists of a total integrated luminosity of 19.7 /fb at centre of mass energy 8 TeV. The selected trigger algorithms require two charged leptons (dilepton) with transverse momentum above thresholds of 17 GeV and 8 GeV, respectively. The background contributions to the signal events come from standard model processes, mainly involving dibosons, photon asymmetric conversion (Dalitz), and non prompt leptons (Fake). Dalitz and Fake are estimated through two methods using data information. The systematic uncertainty related to the background is dominant with respect the statistic errors. The see saw type III model is in details studied in generation phases. The signal is modelled through Monte Carlo simulation technique for different mediators mass values in the range from 140 GeV to 340 GeV. A possible signal contribution in the analysed data sample is investigated through a cut and count experiment. There is no statistical evidence of signal respect the expected standard model background in the 2012 pp collisions data,
so no hints of new physics from see saw type III model is present. The sensitivity of the analysis has been calculated in the background only hypothesis. An upper limits on the production cross sections of the see saw mediators times the branching ratio of the decays with three charged leptons in final states are presented. Then, the upper limits are translated into lower limits on mediators mass value: the observed limit is 240 GeV.

Abstract (italiano)

Questa tesi di fisica sperimentale delle alte energie tratta una ricerca dedicata al meccanismo dell'altalena con mediatori tripletti deboli di fermioni pesanti (tipo III). La ricerca e' basata sui processi dove i mediatori del modello ad altalena sono prodotti attraverso un bosone vettoriale carico e virtuale, e decadono in bosoni vettoriali reali e leptoni carichi standard. Gli stati finali considerati contengono esattamente tre leptoni carichi e standard, energia trasversa mancante, che rivela indirettamente la presenza di neutrini standard, e jets. La somma della carica elettrica dei tre leptoni considerata ha valore unitario, di ambo i segni. Il campione di dati analizzati e' stato raccolto dall'esperimento Compact Muon Solenoid (CMS) all'acceleratore Large Hadron Collider (LHC) del CERN, in Ginevra (Svizzera), nel corso del periodo di presa dati in collisioni protone-protone, relativo al 2012. Tale campione di dati consta di una luminosita' integrata pari a 19.7 /fb con energia disponibile nel centro di massa di 8 TeV. Gli algoritmi di trigger selezionati richiedono due leptoni carichi (dileptoni) con impulso trasverso sopra le soglie di 17 GeV e 8 GeV, rispettivamente. I contributi di fondo agli eventi di segnale provengono da processi del modello standard, principalmente dibosoni, conversioni asimmetriche di fotoni (Dalitz) e leptoni provenienti da vertici secondari (Fake). Dalitz e Fake sono stimati attraverso due metodi, che usano le informazioni provenienti dai dati. L'incertezza sistematica relativa al fondo e' dominante rispetto agli errori statistici. Il modello dell'altalena di tipo III e' studiato dettagliatamente nelle fasi di generazione. Il segnale e' modellato attraverso una tecnica di simulazione Monte Carlo per diversi valori di massa dei mediatori nell'intervallo tra 140 GeV e 340 GeV. Un possibile contributo di segnale nel campione di dati analizzati e' investigato con il metodo dell'esperimento taglia e conta. Non c'e' evidenza statistica di segnale rispetto al fondo previsto dal modello standard nei dati del 2012, cosi' si conclude che nessun indizio di nuova fisica da modello di seesaw tipo III e' presente. La sensitivita' dell'analisi e' stata calcolata nell'ipotesi di solo fondo. Sono presentati i limiti superiori sulle sezioni d'urto di produzione dei mediatori nel modello dell'altalena moltiplicati per il rappporto di decadimento nelle catene che portano stati finali con leptoni carichi. Poi, i limiti superiori sono tradotti in limite inferiore sul valore di massa dei mediatori: il limite osservato e' 240 GeV.

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Tipo di EPrint:Tesi di dottorato
Relatore:Torassa, Ezio
Correlatore:Gasparini, Ugo - Maron, Gaetano
Dottorato (corsi e scuole):Ciclo 26 > Scuole 26 > FISICA
Data di deposito della tesi:29 Gennaio 2014
Anno di Pubblicazione:30 Gennaio 2014
Parole chiave (italiano / inglese):LHC CMS neutrino altalena LHC CMS neutrino see saw
Settori scientifico-disciplinari MIUR:Area 02 - Scienze fisiche > FIS/04 Fisica nucleare e subnucleare
Area 02 - Scienze fisiche > FIS/01 Fisica sperimentale
Struttura di riferimento:Dipartimenti > Dipartimento di Fisica e Astronomia "Galileo Galilei"
Codice ID:6502
Depositato il:14 Nov 2014 11:07
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Le url contenute in alcuni riferimenti sono raggiungibili cliccando sul link alla fine della citazione (Vai!) e tramite Google (Ricerca con Google). Il risultato dipende dalla formattazione della citazione.

S.L.Glashow, “Partial-Symmetries of Weak Interactions”, Nucl. Phys. 22 (1961) 579, doi:doi:10.1016/0029-5582(61)90469-2. Cerca con Google

S.Weinberg, “A Model of Leptons”, Phys. Rev. Lett 19 (1967) 1264, doi:doi:10.1103/PhysRevLett.19.1264. Cerca con Google

D.J.Gross and F.Wilczek, “Ultraviolet Behavior of Non-Abelian Gauge Theories”, Phys. Rev. Lett 30 (1973) 1343, doi:doi:10.1103/PhysRevLett.30.1343. Cerca con Google

H.D.Politzer, “Reliable Perturbative Results for Strong Interactions?”, Phys. Rev. Lett 30 (1973) 1346, doi:doi:10.1103/PhysRevLett.30.1346. Cerca con Google

CMS Collaboration, “Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC”, Phys. Lett. B 716 (Jul, 2012) 30–61, doi:doi:10.1007/JHEP06(2013)081. Cerca con Google

ATLAS Collaboration, “Observation of a New Particle in the Search for the Standard Model Higgs Boson with the ATLAS Detector at the LHC”, Phys. Lett. B 716 (Jul, 2012) 1–29. Cerca con Google

ATLAS Collaboration, “Combined measurements of the mass and signal strength of the Higgs-like boson with the ATLAS detector using up to 25 /fb of proton-proton collision data”, ATLAS-CONF-2013-014 (March, 2013) doi:http://cds.cern.ch/record/1523727. Vai! Cerca con Google

CMS Collaboration, “Measurement of the properties of a Higgs boson in the four-lepton final state”, Phys. Rev. D (2014). Cerca con Google

CMS Collaboration, “Measurement of Higgs boson production and properties in the WW decay channel with leptonic final states”, Journal of High Energy Physics (2014). Cerca con Google

CMS Collaboration, “Search for new physics in events with same-sign dileptons and jets”, JHEP (2013). Cerca con Google

CMS Collaboration, “Search for anomalous production of events with three or more leptons”, CMS Physics Analysis Summary SUS-13-002 (2013). Cerca con Google

K. Hirata, T. Kajita, M. Koshiba et al., “Observation of a neutrino burst from the supernova SN1987A”, Phys. Rev. Lett. 58 (Apr, 1987) 1490–1493, doi:10.1103/PhysRevLett.58.1490. Cerca con Google

C. L. Cowan, F. Reines, F. B. Harrison et al., “Detection of the Free Neutrino: A Confirmation”, Science 124 (1956) 103. Cerca con Google

C. L. Cowan and F. Reines, “The Neutrino”, Nature 178 (1956) 446. Cerca con Google

WMAP Collaboration, “First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Determination of Cosmological Parameters”, Astrophys. J. Suppl. 148 (2003) 175, doi:arXiv:astro-ph/0302209. Cerca con Google

SDSS Collaboration, “Cosmological parameters from SDSS and WMAP”, Phys. Rev. D69 (2004) 103501, doi:10.1103/PhysRevD.69.103501. Cerca con Google

K. Ichikawa, M. Fukugita, and M. Kawasaki, “Constraining neutrino masses by CMB experiments alone”, Phys. Rev. D71 (2005) 043001, doi:10.1103/PhysRevD.71.043001. Cerca con Google

F. Capozzi, G. Fogli, E. Lisi et al., “Status of three-neutrino oscillation parameters, circa 2013”, JHEP (2013). Cerca con Google

DAYA BAY Collaboration, “Spectral measurement of electron antineutrino oscillation amplitude and frequency at Daya Bay”, Phys. Rev. Lett. (2014). Cerca con Google

RENO Collaboration, “Recent Results from RENO”, talk at WIN 2013, XXIV International Workshops on Weak Interactions and Neutrinos (2013) arXiv:hep.if.usp.br/WIN13. Cerca con Google

T2K Collaboration, “Evidence of electron neutrino appearance in a muon neutrino beam”, Phys. Rev. D88 (2013) 032002, doi:10.1103/PhysRevD.88.032002. Cerca con Google

T2K Collaboration, “Measurement of Neutrino Oscillation Parameters from Muon Neutrino Disappearance with an Off-axis Beam”, Phys. Rev. Lett. 111 (2013) 211803. Cerca con Google

MINOS Collaboration, “Electron neutrino and antineutrino appearance in the full MINOS data sample”, Phys. Rev. Lett. 110 (2013) 171801. Cerca con Google

MINOS Collaboration, “Measurement of Neutrino and Antineutrino Oscillations Using Beam and Atmospheric Data in MINOS”, Phys. Rev. Lett. 110 (2013) 251801. Cerca con Google

T. Han and B. Zhang, “Signatures for Majorana neutrinos at hadron colliders”, Phys. Rev. Lett. 97 (2006) doi:10.1103/PhysRevLett.97.171804. Cerca con Google

J. A.-S. F. del Aguila and R. Pittau, “Heavy neutrino signals at large hadron colliders”, JHEP 0710 (2007) doi:10.1088/1126-6708/2007/10/047. Cerca con Google

J. Kersten and A. Y. Smirnov, “Right-Handed Neutrinos at LHC and the Mechanism of Neutrino Mass Generation”, Phys.Rev. D76 (2007) doi:10.1103/PhysRevD.76.073005. Cerca con Google

M. Muhlleitner and M. Spira, “A Note on Doubly-Charged Higgs Pair Production at Hadron Colliders”, Phys.Rev. D68 (2003) doi:10.1103/PhysRevD.68.117701. Cerca con Google

A. Akeroyd and M. Aoki, “Single and Pair Production of Doubly Charged Higgs Bosons at Hadron Colliders”, Phys.Rev. D72 (2005) doi:10.1103/PhysRevD.72.035011. Cerca con Google

Z.-z. X. W. Chao, Z.-G. Si and S. Zhou, “Correlative signatures of heavy Majorana neutrinos and doubly-charged Higgs bosons at the Large Hadron Collider”, Phys.Lett. B666 (2008) doi:10.1016/j.physletb.2008.08.003. Cerca con Google

H. L. R. Foot, X.-G. He, and G. Joshi, “See-saw neutrino masses induced by a triplet of leptons”, Z. Phys. C44 (1989) doi:10.1007/BF01415558. Cerca con Google

T. H. R. Franceschini and A. Strumia, “Type-III see-saw at LHC”, Phys.Rev. D78 (2008) doi:10.1103/PhysRevD.78.033002. Cerca con Google

F. del Aguila and J. Aguilar-Saavedra, “Distinguishing seesaw models at LHC with multi-lepton signals”, Nucl. Phys. B813 (2009) doi:10.1016/j.nuclphysb.2008.12.029. Cerca con Google

C. Biggio and F. Bonnet, “A Simple Realization of the Inverse Seesaw Mechanism”, Phys. Rev. D86 (2012) 035007, doi:10.1103/PhysRevD.86.035007. Cerca con Google

L3 Collaboration, “Search for isosinglet neutral heavy leptons in Z decays”, Phys. Lett. B295 (1992) 371, doi:10.1016/0370-2693(92)91579-X. Cerca con Google

DELPHI Collaboration, “Search for neutral heavy leptons produced in Z decays”, Z. Phys. C74 (1997) 57, doi:doi:10.1007/s002880050370. Cerca con Google

ATLAS Collaboration, “Inclusive search for same-sign dilepton signatures in pp collisions at 7 TeV with the ATLAS detector”, JHEP 10 (2011) 107, doi:doi:10.1007/JHEP10(2011)107, arXiv:arXiv:1108.0366. Cerca con Google

ATLAS Collaboration, “Search for heavy neutrinos and right-handed W bosons in events with two leptons and jets in pp collisions at s = 7 TeV with the ATLAS detector”, Eur. Phys. J. C72 (2012) 2056, doi:doi:10.1140/epjc/s10052-012-2056-4, arXiv:arXiv:1203.5420. Cerca con Google

CMS Collaboration, “Search for heavy Majorana neutrinos in dimuon and dielectron events in pp collisions at 7 TeV”, Phys. Lett. B717 (2012) 109, doi:10.1016/j.physletb.2012.09.012, arXiv:arXiv:1207.6079. Cerca con Google

CMS Collaboration, “A search for a doubly-charged Higgs boson in pp collisions at 7 TeV”, Eur. Phys. J. C72 (2012) 2189, doi:10.1140/epjc/s10052-012-2189-5, arXiv:arXiv:1207.2666. Cerca con Google

M. Swartz, “Limits on doubly charged Higgs boson and lepton flavor violation”, Phys. Rev. D40 (1989) 1521, doi:10.1103/PhysRevD.40.1521. Cerca con Google

M. Swartz, “A search for doubly charged Higgs scalars in Z decay”, Phys. Rev. Lett. 64 (1990) 2877, doi:10.1103/PhysRevLett.64.2877. Cerca con Google

H1 Collaboration, “Search for doubly-charged Higgs boson production at HERA”, Phys. Lett. B638 (2006) 432, doi:10.1016/j.physletb.2006.05.061, arXiv:arXiv:hep-ex/0604027. Cerca con Google

L3 Collaboration, “Search for doubly charged Higgs bosons at LEP”, Phys. Lett. B576 (2003) 18, doi:10.1016/j.physletb.2003.09.082, arXiv:arXiv:hep-ex/0309076. Cerca con Google

DELPHI Collaboration, “Search for doubly charged Higgs bosons at LEP-2”, Phys. Lett. B552 (2003) 127, doi:10.1016/S0370-2693(02)03125-8, arXiv:arXiv:hep-ex/0303026. Cerca con Google

OPAL Collaboration, “Search for the single production of doubly charged Higgs bosons and constraints on their couplings from Bhabha scattering”, Phys. Lett. B577 (2003) 93, doi:10.1016/j.physletb.2003.10.034, arXiv:arXiv:hep-ex/0308052. Cerca con Google

CDF Collaboration, “Search for new physics in high pT like-sign dilepton events at CDF II”, Phys. Rev. Lett. 107 (2011) 181801, doi:10.1103/PhysRevLett.107.181801, arXiv:arXiv:1108.0101. Cerca con Google

ATLAS Collaboration, “Search for anomalous production of prompt like-sign muon pairs and constraints on physics beyond the Standard Model with the ATLAS detector”, Phys.Rev. D88 (2012) 032004, doi:10.1103/PhysRevD.85.032004, arXiv:arXiv:1201.1091. Cerca con Google

F. Del Aguila et al., “Effects of new leptons in electroweak precision data”, Phys. Rev. D78 (2008) 13, arXiv:arXiv:0803.4008. Cerca con Google

C. Biggio and F. Bonnet, “Implementation of the type III seesaw model in FeynRules/MadGraph and prospects for discovery with early LHC data”, Eur. Phys.J. C (2012) 72:1899, doi:10.1140/epjc/s10052-012-1899-z. Cerca con Google

CMS Collaboration, “Search for heavy lepton partners of neutrinos in proton-protoncollisions in the context of the type III seesaw mechanism”, Phys. Lett. B718 (2012) 348, arXiv:arXiv:1210.1797. Cerca con Google

J. Aguilar Saavedra, P. Boavida, and F. Joaquim, “Flavoured searches for type-III seesaw at the LHC”, Phys. Lett. D88 (2013) 113008, doi:10.1103/PhysRevD.88.113008, arXiv:arXiv:1308.3226. Cerca con Google

T. Sjostrand, “A model for initial state parton showers”, Phys. Lett. B157 (1985) 67. Cerca con Google

A. Alloul, N. Christensen, C. Degrande et al., “FeynRules 2.0 - A complete toolbox for tree-level phenomenology”, CERN-PH-TH/2013-239 (2013) arXiv:arXiv:1310.1921. Cerca con Google

J. Alwall, M. Herquet, et al., “MadGraph 5 : Going Beyond”, JHEP 1106 128B517 (2011) 128, doi:10.1007/JHEP06(2011)128. Cerca con Google

T. Sjostrand, S. Mrenna, and P. Skands, “PYTHIA 6.4 physics and manual”, JHEP 05 (2006) 026, doi:10.1088/1126-6708/2006/05/026, arXiv:hep-ph/0603175. Cerca con Google

CMS Collaboration, “Detector and Software Technical Design Report”, CERN-LHCC-2006-001 1 (2006) doi:http://cds.cern.ch/record/922757. Vai! Cerca con Google

C. Degrande et al., “UFO - The Universal FeynRules Output”, Comput. Phys. Commun. 183 (2012) doi:10.1016/j.cpc.2012.01.022. Cerca con Google

S. Agostinelli et al., “GEANT4: A Simulation toolkit”, Nucl.Instrum.Meth. A506 (2003) 250, doi:10.1016/S0168-9002(03)01368-8. Cerca con Google

I. Wolfram Research, “Mathematica”, Version 9.0 (2012). Cerca con Google

CMS Collaboration, “The CMS experiment at the CERN LHC”, JINST 03 (2008) S08004,doi:10.1088/1748-0221/3/08/S08004. Cerca con Google

CMS Collaboration, “Tracker Technical Design Report”, CERN/LHCC 98-6 (1998). Cerca con Google

CMS Collaboration, “CMS ECAL Technical Design Report”, CERN/LHCC 97-33 (1997). Cerca con Google

CMS Collaboration, “CMS HCAL Technical Design Report”, CERN/LHCC 97-31 (1997). Cerca con Google

CMS Collaboration, “CMS MUON Technical Design Report”, CERN/LHCC 97-32 (1997). Cerca con Google

M. Gulmini et al., “Run Control and Monitor System for the CMS experiment”, in Computing in high energy and nuclear physics. 2003. La Jolla (California). Cerca con Google

M. Biasotto et al., “The Legnaro-Padova distributed Tier-2:challenges and results”, in Computing in high energy and nuclear physics. 2013. Cerca con Google

CMS Collaboration, “Particle flow event reconstruction in CMS and performance for jets, taus, and missing transverse energy”, CMS Physics Analysis Summary CMS-PAS-PFT-09-001 (2009). Cerca con Google

CMS Collaboration, “Commissioning of the particle-flow event reconstruction with the first LHC collisions recorded in the CMS detector”, CMS Physics Analysis Summary CMS-PAS-PFT-10-001 (2010). Cerca con Google

CMS Collaboration, “Commissioning of the particle-flow reconstruction in minimum-bias and jet events from pp collisions at 7 TeV”, CMS Physics Analysis Summary CMS-PAS-PFT-10-002 (2010). Cerca con Google

CMS Collaboration, “Particle-flow commissioning with muons and electrons from J/Psi, and W events at 7 TeV”, CMS Physics Analysis Summary CMS-PAS-PFT-10-003 (2010). Cerca con Google

M. Cacciari, G. P. Salam, and G. Soyez, “The anti-k t jet clustering algorithm”, JHEP 04 (2008) 063, doi:10.1088/1126-6708/2008/04/063, arXiv:0802.1189. Cerca con Google

CMS Collaboration Collaboration, “Determination of Jet Energy Calibration and Transverse Momentum Resolution in CMS”, JINST 6 (2011) 11002, doi:10.1088/1126-6708/2008/04/063, arXiv:1107.4277. Cerca con Google

Z. Was, “TAUOLA the library for tau lepton decay, and KKMC-KORALB-KORALZ status report”, Nucl.Phys.Proc.Suppl. 98 (2001) 96, doi:10.1016/S0920-5632(01)01200-2, arXiv:hep-ph/0011305. Cerca con Google

CMS Collaboration, “Measurement of WZ production rate”, CMS Physics Analysis Summary CMS-PAS-SMP-12-006 (2013). Cerca con Google

CMS Collaboration, “Measurement of W+W- and ZZ production cross sections in pp collisions at sqrt(s) = 8 TeV”, Phys. Lett. B721 (2013) 190, doi:10.1016/j.physletb.2013.03.027, arXiv:arXiv:1301.4698. Cerca con Google

CMS Collaboration, “Measurement of the t t-bar production cross section in the dilepton channel in pp collisions at 8 TeV”, JHEP (2014) arXiv:arXiv:1312.7582. Cerca con Google

CMS Collaboration, “Measurement of inclusive W and Z boson cross sections in pp collisions at 8 TeV”, CMS-PAS-SMP-12-011 (2014) arXiv:http://cds.cern.ch/record/1460098. Vai! Cerca con Google

CMS Collaboration, “Search for new physics in events with same-sign dileptons and b jets in pp collisions at 8TeV”, JHEP 03 (2013) 037, doi:10.1007/JHEP03(2013)037. Cerca con Google

CMS Collaboration, “Background and Efficiency Determination Methods for Multilepton Analyses”, AN Analysis Note AN-2012-257 (2012). Cerca con Google

CMS Collaboration, “A search for anomalous production of events with three or more leptons using 19.5 /fb of 8 TeV LHC data”, AN Analysis Note AN-2012-343 (2012). Cerca con Google

CMS Collaboration, “Search for new physics in a final state with same-sign lepton pair, jets, and missinge transverse energy using the full 2012 CMS dataset”, AN Analysis Note AN-2013-120 (2013). Cerca con Google

CMS Collaboration, “Inclusive W/Z cross section at 8 TeV”, CMS Physics Analysis Summary CMS-PAS-SMP-12-011 (2013). Cerca con Google

ATLAS Collaboration, “ATLAS detector and physics performance : Technical Design Report, 2”, CERN-LHCC-99-015 (1999) arXiv:http://cds.cern.ch/record/391177. Vai! Cerca con Google

ATLAS Collaboration, “Search for Type III Seesaw Model Heavy Fermions in Events with Four Charged Leptons using 5.8 /fb of 8 TeV data with the ATLAS Detector”, ATLAS-CONF-2013-019 (2013) doi:http://cds.cern.ch/record/1525526. Vai! Cerca con Google

L. Moneta et al., “The RooStats Project”, in 13th International Workshop on Advanced Computing and Analysis Techniques in Physics Research (ACAT2010). SISSA, 2010. arXiv:1009.1003. PoS(ACAT2010)057. Cerca con Google

ATLAS, CMS Collaboration, “Procedure for the LHC higgs boson search combination in Summer2011”, atl-phys-pub 2011-11/cms note, 2011/005 (2011), LHCforse, (2011). Cerca con Google

CMS Collaboration, “Search for W’/technirho in WZ using leptonic final states”, CMS Physics Analysis Summary CMS-PAS-EXO-12-025 (2013). Cerca con Google

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