1 / 42

Precision Study of Higgs Boson at LHC and Future Colliders

This text discusses the precision study of the Higgs boson, including its couplings and decay widths, at the LHC and future colliders such as the t.H Full HL-LHC, Z.W.b..ILC, and m-Collider. It explores the potential for discovering new physics and the importance of invisible decays in understanding dark matter.

amye
Download Presentation

Precision Study of Higgs Boson at LHC and Future Colliders

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. LHCwillstudy the Higgs boson H(126) up to a certain level of precision whichisassumed to be a few percent for manycouplings, bb, tt, WW, ZZ, , ,  ... estimates for Z and cc and betterresults for ratios of branching ratios. The self couplingwillprobablyremainatprecision of ~30%, and the invisible decaymaybeprobedat 5-10% level. New physicsisexpected to show up atanylevel of precision, but itis generallyacceptedthat a precision of a few permilisneeded to discover (5) TeVscale new physics. Invisible decaysare of particularinterest as any invisible decaywidth is a potentialsign of darkmatter

  2. t H Full HL-LHC Z W b  ILC : good! but not a radical improvement over HL-LHC can one do better? 

  3. HiggsFactoriesDreams

  4. S. Henderson

  5. m+m-Collider vse+e-Collider ? • A m+m-collider can do things that an e+e-collider cannot do • Direct coupling to H expected to be larger by a factor mm/me • ,jh[speak = 70 pb at tree level] • Can it be built + beam energy spread dE/E be reduced to 3×10-5 ? • 4D+6D Cooling needed! • For dE/E = 0.003% (dE~ 3.6 MeV, GH ~ 4 MeV) • no beamstrahlung, reduced bremsstrahlung • Corresponding luminosity ~ 1031 cm-2s-1 • Expect 2300 Higgs events in 100 pb-1/ year • Using g-2 precession, beam energy and energy spectrum • Can be measured with exquisite precision (<100 keV) • From the electrons of muon decays • Then measure the detailed lineshape of the Higgs at √s ~ mH • Five-point scan, 50 + 100 + 200 + 100 + 50 pb-1 • Precision from H→bb and WW : [16,17] , W, … , W, … s (pb) √s s(mH), TLEP HF2012 : Higgs beyond LHC (Experiments)

  6. In a nutshell: -+-  colliderallowsHiggs production in s-channel -- Luminosityislimited -- Luminosityspectrumdeterminationneedsconvincing proof -- There remains a global unknownnormalization factor -- Possible add-on to ILC or CLIC -- Possibly excellent for H coupling and CP states -+-  colliderallowsHiggs production in s-channel -- requiresextremelysmallenergyspread E/E < H/MH = 4.2 MeV/126 GeV = 4 10-5 -- Luminositylimited by power on muon production target (4MW) -- unique for scenarios in whichthere are severalnarrowresonances or where the H line shapeis non conventional -- remain to demonstrateionizationcooling, emitance exchange and reproducibility of center of mass energy both are veryspecialized

  7. e+ e- colliders ILC CLIC LEP3/TLEP main differences: -- luminosity vs energydependence -- high energyreach -- upgrade path -- resolution and precision in center-of-mass energy -- ILC islinear and «ready» -- TLEP iscircular and begins design study main quality: e+e-  Z H (Higgs tag by recoil mass to Z decay)

  8. Performance of e+ e- colliders TLEP : Instantaneous lumi at each IP (for 4 IP’s) Instantaneous lumi summed over 4 IP’s Z, 2.1036 WW, 6.1035 HZ, 2.1035 tt , 5.1034 • Luminosity : Crossing point between circular and linear colliders ~ 4-500 GeV As pointed out by H. Shopper in ‘The Lord of the Rings’ (Thanks to Superconducting RF…) • Circular colliders can have several IP’s . Sum scales as ~(NIP)0.5 – 1 use 4 IP machine as more reliable predictions using LEP experience

  9. Higgs production mechanism In e+e– the Higgs is produced by “higgstrahlung” close to threshold Production xsection has maximum near threshold ~200 fb 1034/cm2/s  20’000 HZ events per year. H – tagging by missing mass to Z decay e- H Z* Z e+ For a Higgs of 125GeV, a centre of mass energy of ~240GeV is best  kinematical constraint near threshold for high precision in mass, width, selection purity

  10. ILC Z – tagging by missing mass total rate  gHZZ2 ZZZ final state  gHZZ4/ H  measure total widthH emptyrecoil = invisible width ‘funnyrecoil’ = exoticHiggsdecay easy control belowtheshold e- H Z* Z e+

  11. Hvvadvantageous for ILC & CLIC as L E_cm

  12. What about a circular machine? LEP2 was not that far after all. One year of LEP2  ~200pb-1 x 4 exp. need 100fb-1! How can one increase over LEP 2 (average) luminosity by a factor 500 withoutexploding the power bill? Answeris in the B-factory design: a verylow vertical emittance ring with higherintrinsicluminosity electrons and positrons have a muchhigher chance of interacting  muchshorterlifetime (few minutes)  feedbeamcontinuouslywith a ancillaryaccelerator

  13. prefeasibilityassessment for an 80km projectat CERN John Osborne and Caroline Waiijer ESPP contr. 165

  14. http://arxiv.org/abs/1305.6498. CONSISTENT SET OF PARAMETERS FOR TLEP TAKING INTO ACCOUNT BEAMSTRAHLUNG new parameter set to beproduced by Jan’14

  15. TLEP: PARAMETERS & STATISTICS(e+e- -> ZH, e+e- →W+W-, e+e- →Z,[e+e-→t ) 10 ILC 40 ILC 100 ILC 1000 ILC 2.5 at the Z pole repeat the LEP physics programme in a few minutes…

  16. BEAMSTRAHLUNG Luminosity E spectrum Effect on top threshold  Beamstrahlung @TLEP is benign: particles are either lost or recycled on a synchrotron oscillation  some increase of energy spread but no change of average energy Little EM background in the experiment.

  17. the 10B$ ILC TLEP NB : thisis not a very good comparisonwith LHC as correlationbetweenchannels  some ratios of BRsbeingcanbe more precise observables than the couplingsthemselves.

  18. Higgs Physics with e+e- colliders above 350 GeV? 1. Similar precisions to the 250/350 GeV Higgs factory for W,Z,b,g,tau,charm, gamma and total width. Invisible width best done at 240-250 GeV. 2. ttHcoupling possible withsimilarprecision as HL-LHC (4%) 3. Higgs self couplingalsoverydifficult… precision ~30% at 1 TeVsimilar to HL-LHC prelim. estimates 10-20% at 3 TeV (CLIC)  percent-levelprecisionneeds 100 TeV pp machine  For the study of H(126) alone, and given the existence of HL-LHC, an e+e- colliderwithenergyabove 350 GeVis not compelling w.r.t. one working in the 240 GeV – 350 geVenergy range.  The stronger motivation for a high energye+e- colliderwillexist if new particlefound (or inferrred) at LHC, for whiche+e- collisions wouldbringsubstantial new information

  19. TERA-Z and Oku-W Precision tests of the closure of the Standard Model

  20. Z pole ssymmetries, lineshape WW threshold scan tt threshold scan - • TLEP : Repeat the LEP1 physics programme every 15 mn • Transverse polarization up to the WW threshold • Exquisite beam energy determination (10 keV) • Longitudinal polarization at the Z pole • Measure sin2θW to 2.10-6 from ALR • Statistics, statistics: 1010 tau pairs, 1011 bb pairs, QCD and QED studies etc… Precision tests of EWSB

  21. EWRCs relations to the well measured GF mZ aQED at first order: Dr = a /p (mtop/mZ)2 - a /4p log (mh/mZ)2 e3 = cos2qwa /9p log (mh/mZ)2 dnb=20/13 a /p (mtop/mZ)2 completeformulaeat 2d order includingstrong corrections are available in fitting codes e.g. ZFITTER , GFITTER Will need to beimproved for TLEP!

  22. Example (fromLangacker& ErlerPDG 2011) ρ=1=(MZ) . T 3=4 sin2θW (MZ) . S ρtoday= 0.0004+0.0003−0.0004 -- is consistent with 0 at 1 -- is sensitive to non-conventionalHiggs bosons (e.g. in SU(2) triplet with ‘funnyv.e.v.s) -- is sensitive to Isospin violation such as mt  mb Most e.g. SUSYmodels have thesesymmetries embeddedfrom the start Presentmeasurementimplies Similarly:

  23. NEUTRINO CONNECTIONS The onlyknown BSM physicsat the particlephysicslevelis the existence of neutrino masses -- There is no unique solution for mass terms: Diraconly? Majoranaonly? Both? -- if Both, the existence of (2 or 3) families of massive right-handed (sterile) i ,i neutrinos ispredicted («see-saw» models) but masses are unknown (eV to 1010GeV) -- mixingwith active neutrinos leads to various observable consequences -- if very light (eV) , possible effect on neutrino oscillations -- if mixing in % or permillevel, possiblymeasurableeffects on -- PMNS matrix unitarity violation and deficit in Z invisible width -- occurrence of Higgs invisible decaysH ii -- violation of unitarity and lepton universality in W or decays -- etc etc.. -+- many more examples

  24. Neutrino countingat TLEP given the very high luminosity, the followingmeasurementcanbeperformed The common tag allowscancellation of systematics due to photon selection, luminosity etc. The others are extremelywellknown due to the availabilityof O(1012 ) Z decays. The full sensitivity to the number of neutrinos isrestored , and the theoryuncertainty on is veryverysmall. A good measurementcanbe made from the data accumulatedat the WW threshold where ( Z(inv) ) ~4 pb for |cos| <0.95 161 GeV(107 s) running at 1.6x1035/cm2/s x 4 exp 3x107  Z(inv) evts,  =0.0011 adding 5 yrs data at 240 and 350 GeV ............................................................  =0.0008 A better point maybe 105 GeV (20pb and higherluminosity) mayallow  =0.0004?

  25. Words of caution: 1. TLEP will have 5.104 more luminositythan LEP at the Z peak, 5.103at the W pair threshold. Predictingachievableaccuracieswithstatisticalerrorsdecreasing by 250 isverydifficult. The studyisjustbeginning. 2. The following table are ‘plausible’ precisionsbased on myexperience and knowledge of the present limitations, most of whichfromhigherorder QED corrections (ex. production of additional lepton pairs etc..). Manycan have experimental cross-checks and errorsmaygetbetter. 3. The mostserious issue isthe luminositymeasurementwhich relies on the calculations/modeling of the low angle Bhabhascattering cross-section. This dominates the measurement of the hadronic cross section at the Z peakthus the determination of Nv(test of the unitarity of the PMNS matrix) 4. The followingisonly a sample of possibilities. With 1012 Z decays, there are many, many more powerfulstudies to performat TERA-Z e.g. flavourphysicswith 1011 bb, cc , 1010  etc…

  26. Measurement of ALR Verifiespolarimeterwithexperimentallymeasured cross-section ratios ALR = statistics ALR = 0.000015 with 1011 Z and 40% polarization in collisions. sin2θWeff(stat) = O(2.10-6)

  27. NB without TLEP the SM line would have a 2.2 MeV width

  28. Nextsteps

  29. December 2011: 2 authors 128 authors September 2013: Nextsteps?

  30. 337 registered participants to the TLEP design study

  31. Michael Benedikt The twopillars: pp and e+e- mandate is to deliver full CDR for both machines with an extendedcostreview

  32. Team for kick-off and study preparation Future Circular Colliders - Conceptual Design Study Study coordination, host state relations, global cost estimate Benedikt, Zimmermann High Field Magnets L. Bottura Supercon-ducting RF E. Jensen Cryogenics L. Tavian Specific Technologies (MP, Coll, Vac, BI, BT,PO) JM. Jimenez VL Hadron collider D. Schulte Infrastructure, cost estimates P. Lebrun e+ e- collider J. Wenninger Hadron injectors B. Goddard Physics and experiments Hadron physic Experiments, infrastructure A. Ball, F. Gianotti, M. Mangano e+ e- exper., physics A. BlondelJ.Ellis, P.Janot e- p physics + M. Klein e- p option Integration aspects O. Brüning Operation aspects, energy efficiency, OP & mainten., safety, environment. P. Collier Planning (Implementation roadmap, financial planning, reporting) F. Sonnemann PP-130924-MBE_FCC Design Study_ED

  33. TLEP design study structure -- ad interim International Advisoryboard Steering group web site, mailing lists, speakers board, etc.. Institutionalboard Aleksan, Azzi, Blondel, Ellis, Janot, Klute, Koratzinos, Wenninger, Zanetti, Zimmermann + Benedikt invited Accelerator Experiments Phenomenology Ellis Janot Wenninger 1.Optics, lowbeta, alignment and feedbacks 2. Beambeam interaction 3. Magnets 4.RF system  5. Top-up injection 6.Injectorsystem & sources 7. Integration w/(VHE)-LHC 8. MDI, Interaction region 9. Vacuum 10. Polarization &E-calib. 11. Civil Engineering  12.Elements of costing 1. EW physicsat Z pole 2. WW, ZZ, Zphysics 3. H(126) properties 4. Top quark physics 5. Flavour (b,c,  , ) physics 6. QCD and  physics 7. rare decays & new physics 8.Experimentalenvironment 9. offline computing 10. Online computing 11. Detector design 1. model building 2.Precision EW calculations 3.Flavour (b,c,  , ) physics 4. QCD and  physics 5.rare decays & new physics 6. Combination + complementaritywith LHC and other machines ; global analysis There willbe a single Advisoryboard and Institutionalboard for the FCC study The technicalwork-packages willbeintegrated (RF, magnets, infrastructure, costs) Proto-convener for each group beingappointed.

  34. Design Study : http://tlep.web.cern.ch cansuscribe for work, informations, newsletter , etc… Global collaboration: collaboratorsfrom Europe, US, Japan, China  Nextevents: regular TLEP phone conferences (nextis 11 November) Joint VHE-LHC+ TLEP kick-off meeting 12-14 February 2014

  35. Conclusions The combination of TLEP and the VHE-LHC offers, for a great cost effectiveness, the best precision and the best search reach of all options presentlyon the market. First look at The Physics Case of TLEP arXiv:1308.6176v2 [hep-ex] 22 Sep 2013

  36. Conclusions 1. the global design study for Future CircularColliders has nowbegunat CERN. Maybe the birth of another 50 grand years of physics! 2. mandate to deliver full design study for e+e- and pp for nextEuropeanStrategy(2018?)

More Related