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CMS Observation of a new boson at the LHC and its implications for the origin of mass.

CMS Observation of a new boson at the LHC and its implications for the origin of mass. . Wim de Boer (for the CMS Collaboration). Outline. Evidence for a Higgs particle in CMS Is it Peter´s Higgs or just a Higgs? What it has to do with the “origin of mass” in the universe?

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CMS Observation of a new boson at the LHC and its implications for the origin of mass.

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  1. CMS Observation of a new boson at the LHC and its implications for the origin of mass. Wim de Boer (for the CMS Collaboration)

  2. Outline • Evidencefor a Higgs particle in CMS • Is itPeter´s Higgs or just a Higgs? • What it has to do with the “origin of mass” in the universe? • What is the Higgs boson good for? • What is so special about observed Higgs particle?

  3. The LHC Two rings with 1232superconducting dipoles and 858 quadrupoles,26,7 km circumference max. 2808 proton bunches, 40 MHZ collision rate, ~1011 Protons / bunch ~500 million pp collisions / s at 7 & 8 TeV centre of mass energy Bendingmagnets Cavitiesforacceleration

  4. Design Criteria for the CMS Experiment First conceptual design of a “Compact Muon Solenoid” (CMS) was presented in Aachen (1990) based on a 4 Tesla solenoid. • Very good muon identification and momentum measurement. • H® ZZ, with Z®mm • Most precise photon detector. • H®gg • Powerful inner tracking for electron identification. • H®ZZ, Z®ee • Hermetic calorimetry for missing ET signatures: H®WW, W® mn From M. Della Negra, Wess-prizerecipient (with P. Jenny), 2013, Karlsruhe

  5. Compact Muon Solenoid (CMS) Experiment 3.8 T Magnet Bend tracks of charged particles Calorimeters Absorb particles and measure their energy Silicon Detectors Measure tracks left by charged particles Muon Detectors Identify and measure muons that penetrate z 0 (center)

  6. CMS Collaboration 1400 Physicists 600 Graduate students 175 Institutes 38 Countries

  7. Assembly in the surface hall Waiting for the cavern to be ready

  8. Descent of the central wheel (2000 tons)

  9. Heart of CMS: all silicon tracker (200 m2!) Pile-up: many collisions pro bunch crossing 66 million silicon pixels: 100  150 µm2 9.3 million silicon microstrips: 80µm - 180µm. ~200 m2 of active silicon area (cf ~ 2m2 in LEP detectors) ~13 precise position measurements (15 µm ) per track.

  10. 78 reconstructed vertices in high pile-up run

  11. Dimuonmassresolution 24 yearsofe+e- machines 24 hoursof LHC

  12. LHC Luminosity New records:–centre-of-mass energy 8 TeV – peak luminosity 0.77∙ 1034 / cm² /sec – best week ∫L=1.35 fb-1 ( 75% design luminosity @ half energy & half # of bunches) (delivered) TAM 2013 HCP 2012 summer conferences 2012

  13. Status of Higgs Hunt in July 2012

  14. pp processes in Standard Model 9 ordersofmagnitude: 1 in a billion 7 14 TeV Higgs events are rare ! Need 5x more lumi at 14 TeV to discover 500 GeV Higgs

  15. well understood SM background

  16. Higgs Production at the LHC „gluon fusion“ „vector boson fusion“ „vector boson radiation“ „tt associated produktion“ Rate @ 8 TeV 25-50% higher than7 TeV

  17. Higgs branchingratios Note that q,l width ~ M while W,Z width ~ M3. Hence bb dominates below WW “threshold”.  is down by ~ 9 due to coupling to mass, and 1/3 color factor.

  18. Higgs branchingratios • bb dominates below WW threshold. •  is down by ~ 9 due to coupling to mass, and 1/3 color factor. • WW higher than ZZ because distinguisable particles: • In addition phase space. Weare lucky withMh=126 GeV: bb down to 60 % and „golden“ channels ZZ->4l andalreadyappreciable! (golden, sincetheyshownarrow invariant masspeakwithwidth limited by experimental resolution)

  19. Searching for the Higgs in the four leptons final state For a low mass Higgs the fourth lepton is soft. Selection cuts: Electrons pT > 7 GeV MuonspT > 5 GeV 40 GeV < m12 < 120 GeV m34 > 12 GeV

  20. Higgscandidate ZZ event (8TeV) with 2 µ and 2 e

  21. H ® ZZ ® 4 leptons 6 7 Expected: BG:9.4, SIGNAL: 18.6 Total: 28 Observed: 25Signal strength: 0.9 0.3 Significance 6.7 s(7.2 s exp) Mass: 125.8 ± 0.5 (stat) ± 0.2 (syst) GeV

  22. December 2012 data Significance 4.5 s Mass 126.2 ± 0.6 (stat) ± 0.2 (syst) GeV

  23. Search for the SM Higgs boson in the gg channel Mass resolution is the key for Higgs discovery in this channel H®gg Simulation (100 fb-1) PbWO4 crystals Test Beam October 2003 sm/m = 0.5 [sE1/E1sE2/E2cot(q/2)Dq] Target for the intercalibration < 0.5%

  24. Mass resolution of gg system: Find the right vertex g1 g2 sm/m = 0.5 [sE1/E1sE2/E2cot(q/2)Dq] Need vertex to betterthan 10 mm, bunch 50 mm • Algorithm to find the right vertex based on SpT2 of tracks and pTgg balance. • Tested on Z®mmevents by treating muons as gammas. • Overall efficiency to find the right vertex for Higgs (m = 120 GeV) integrated • over pT spectrum: ~ 80%

  25. Diphoton Candidate

  26. gg Mass Distribution Background is estimated from the data by a polynomial fit. An excess is observed consistent with a narrow resonance around 125 GeV mass at 4.1 s

  27. Outline • Evidencefor a Higgs particle in CMS • Is itPeter´s Higgs or just a Higgs? • What it has to do with the “origin of mass” in the universe? • What is the Higgs boson good for? • What is so special about observed Higgs particle?

  28. Other Channels • Search for the Higgs in other decay modes : WW, bb and tt • Combined significance at MH=125.8 GeV: 6.9 s • Overall satisfactory level of compatibility withthe SM cross section. • Combined s/sSM= 0.88 ± 0.21 (so signal consistent with Peter’s Higgs)

  29. A first glimpse at SpinParity • Spin 0  2 S=1 particles • angular correlations. • Positive parity 12 allowed  • decay planes aligned. • Negative parity12allowed • decay planes orthogonal in favour of 0+ ! p(0–) = 0.072 p(0+) = 0.72 So spin and parity consistent with Peter’s Higgs

  30. Couplingsforvariouschannels

  31. Fit of generalized couplings So couplings consistent with Peter’s Higgs

  32. Outline • Evidencefor a Higgs particle in CMS • Is itPeter´s Higgs or just a Higgs? • What it has to do with the “origin of mass” in the universe? • What is the Higgs boson good for? • What is so special about observed Higgs particle?

  33. Is Higgs Field the „Origin ofMass“? Answer: YesandNo. Energyormass in Universehaslittleto do with Higgs field. Higgs fieldgivesonlyelementaryparticlesmass. Mass in universe: Atoms: mostofmassfrombindingenergyofquarks in nuclei, providedbyenergy in colourfield, not Higgs field.(bindingenergy  potential energyofquarks  kinetic energieofquarks, ca. 1 GeV, massofu,dquarksbelow1 MeV!) 2) Massofdarkmatter: unknown, but in Supersymmetrybybreakingofthissymmetry, not bybreakingofelectroweaksymmetry. Dark energy: Higgs energydensityseemstoo large. Why?Giganticproblem! darkenergy= 0.7 matter = 0.3

  34. The giganticdarkenergyproblem Acceleratedexpansionofuniverseimplies a constantenergydensity in space time, either a cosmologicalconstantorsomekindofvacuumenergy. The Higgs fieldisthoughtofaspermeatingspace time with a constantenergydensity, whichcanbeeasilyestimatedfromtheeffective potential tobe 55 ordersofmagnitudeabovethedarkenergydensityofabout 10-29 g/cm3 Ifzero-pointfluctuationsoffieldconsideredandintegratedto Planck scale, problemevenmoresevere: (1018)4 GeV4 = 120 ordersofmagnitude larger thanthedarkenergydensity In Supersymmetryproblemsomewhatless, sinceabovebreakingscalefermionsandbosons cancel in zero-pointfluctuations, problem„only“ 60 ordersofmagnitude. V(=0) = -mH2mW2/2g2 = O(108 GeV4) = 1026 g/cm3 1 GeV4=(GeV/c2 )(GeV3/(ħc)3) = 10-24 g 1042 cm-3 = 1018 g/cm3 Averagedensity in universe: crit= 2.10-29 g/cm3 WHY IS THE UNIVERSE SO EMPTY???

  35. Outline • Evidencefor a Higgs particle in CMS • Is itPeter´s Higgs or just a Higgs? • What it has to do with the “origin of mass” in the universe? • What is the Higgs boson good for? • What is so special about observed Higgs particle? • Does the observation point to physics beyond the Standard Model?

  36. Whatisthe Higgs bosongoodfor? Answer: without Higgs fieldwewould not exist! E.g. Itgivesmasstotheelectron: withoutelectronmassnoatoms (r1/me) Itgivesmasstothe W,Z bosons, whichmakeweakinteractionsweakatlowenergy, so thesunshinesfor 8 billionyears

  37. Outline • Evidencefor a Higgs particle in CMS • Is itPeter´s Higgs or just a Higgs? • What it has to do with the “origin of mass” in the universe? • What is the Higgs boson good for? • What is so special about the observed Higgs particle?

  38. Whatis so specialaboutthe Higgs boson? Higgs massbelow 130 GeV, as PREDICTED by SUSY! W. Hollik: formetheobserved Higgs bosonwith a massconsistent withSupersymmetryisthestrongesthintforSupersymmetry!

  39. Other beautiful SUSY features • SUSYprovides UNIFICATION ofgaugecouplings • SUSYprovides UNIFICATION of Yukawa couplings • SUSYhasnoquadraticdivergenciesHiggs mass • canbecalculateduptounificationscale • SUSYpredicts EWSB withlightest Higgsbelow 130 GeV • LHC: Mh= 126 GeV • SUSYprovides„dark matter miracles“: • Neutralinoannihilation x-section a fewpb • correctrelicdensity • Neutralino-nucleonscatteringcrosssection • < 10-8pbconsistentwith experimental limits

  40. Unificationfor TeV SUSY masses U. Amaldi, WdB, H. Fürstenau, PLB, 1991, wdb. C, Sander, PLB 2004, hep-ph/0307049 iaregaugecouplingsof SU(3)SU(2)LU(1) (in first order i  1/log (energy Q)

  41. Higgs mechanismuspredicted in SUSY Common masses at GUT scale: m0for scalars m1/2for S=1/2 gauginos m1,m2for Higgs bosons m2driven negative by top loops , electroweak symmetry breaking at MZfor 140<Mt<200 GeV! BINGO, Mtop predicted in this range by SUSY and it was found at 171 ± 1.3 GeV! EWSB only works if starting point at GUT scalenot too large: need   EW scale, but it is term of supersymm. potential, could be GUT scale (-problem)

  42. NMSSM solves-problem <S> is  termofMSSM. If isvevfromsinglet S, noproblemtobesmall. Now3 scalar Higgs bosons! (and 2 pseudoscalar) MSSM NMSSM

  43. Higgs mass in MSSM and NMSSM MSSM Higgs mass in MSSM 125 GeV formstop 3TeV NMSSM: mixingwithsinglet increases Higgs massat BORN level forsmall tan and large  NO MULTI-TEV stopsneeded

  44. Branchingratios in NMSSM maydifferfrom SM • Total widthof 126 GeV Higgs totmaybereducedsomewhatbymixingwithsinglet(singletcomponentdoes not coupleto SM particles). • Thenbranchingratiosenhanced, e.g. • BR(H tot enhanced (enhancementmaybereducedbylightstopsatgluonfusionloopby neg. interferencewith top loops) • Main decaymode BR(H bbarbbartot hardlyeffected, aslongasbbar  tot • Higgs withlargestsingletcomponentusuallylightestone. Sinceithassmallcouplingsto SM particles, itis NOT excludedby LEP limit.

  45. Status of NMSSM Manypapers on NMSSM after Mh=126 GeV and hintoftoohighBrinto, seearXiv:1301.6437, arXiv:1301.1325, arXiv:1301.0453, arXiv:1212.5243, arXiv:1211.5074, arXiv:1211.1693, arXiv:1211.0875, arXiv:1209.5984, arXiv:1209.2115, arXiv:1208.2555, arXiv:1207.1545, arXiv:1206.6806, arXiv:1206.1470, arXiv:1205.2486, arXiv:1205.1683, arXiv:1203.5048, arXiv:1203.3446, arXiv:1202.5821, arXiv:1201.2671, arXiv:1201.0982, arXiv:1112.3548, arXiv:1111.4952, arXiv:1109.1735, arXiv:1108.0595, arXiv:1106.1599, arXiv:1105.4191, arXiv:1104.1754, arXiv:1101.1137, arXiv:1012.4490, ……….. NMSSM consistentwith h1=95 GeV, h2=126 GeV, motivatedby 2 excessobservedat LEP at 95 GeV withsignalstrength 2 well below SM. Hardtodiscoverat LHC, maybe in decaymode h3h2+h1

  46. Determining allowed SUSY parameter range Variables calculated with NMSSMTools 3.2.4 using Ulrich Ellwanger*, John F. Gunion**, Cyril Hugonie*** http://www.th.u-psud.fr/NMHDECAY/nmssmtools.html MicrOMEGAs 2.4.1 G. Bélanger, F. Boudjema, P. Brun, A. Pukhov, S. Rosier-Lees, P. Salati, A. Semenov http://lapth.in2p3.fr/micromegas/ Minuit for minimization These dominate parameterspace • LHC limits on squarksandgluinos. • Mh=126 GeV

  47. Allowedparameterspace LEP Xenon +MA LHC Bs

  48. LHC exclusionat 7 and 14 TeV

  49. Expected Higgs masses in NMSSM

  50. Expected Higgs decays in NMSSM

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