Physics prospects for the LHC

Transcription

1 Physics prospects for the LHC Georg Weiglein DESY Abingdon, 09 / 2011 Introduction Physics of electroweak symmetry breaking New physics addressing the hierarchy problem Conclusions Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.1

2 Introduction Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.2

3 Introduction LHC results so far, executive summary: Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.2

4 Introduction LHC results so far, executive summary: Impressive rediscovery of the known ingredients of the Standard Model Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.2

5 Introduction LHC results so far, executive summary: Impressive rediscovery of the known ingredients of the Standard Model No evidence for new physics yet Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.2

6 LHC physics: exploring the Terascale 1 TeV 1000 m proton m mev Temperature / Energy ev kev MeV GeV TeV Atomic physics Nuclear physics Particle physics Cathode ray tube Cyclotron LEP, SLC Tevatron ILC, LHC W, Z Higgs W, topz SUSY Higgs Extra Dimensions Inflation CMB BBN Baryogenesis photon Neutrino WIMP Decoupling Decoupling Decoupling Lambda Matter Radiation dominated now 10^17 10^12 10^6 1 Time (s) 10^ 6 10^ 12 Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.3

7 What can we learn from exploring the new territory of TeV-scale physics? Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.4

8 What can we learn from exploring the new territory of TeV-scale physics? How do elementary particles obtain the property of mass: what is the mechanism of electroweak symmetry breaking? Is there a Higgs boson (or more than one)? Do all the forces of nature arise from a single fundamental interaction? Are there more than three dimensions of space? Are space and time embedded into a superspace? What is dark matter? Can it be produced in the laboratory? Are there new sources of CP-violation? Can they explain the asymmetry between matter and anti-matter in the Universe?... Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.4

9 Higgs: last missing ingredient of the Standard Model But: the Standard Model cannot be the ultimate theory Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.5

10 Higgs: last missing ingredient of the Standard Model But: the Standard Model cannot be the ultimate theory The Standard Model does not include gravity breaks down at the latest at M Planck GeV Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.5

11 Higgs: last missing ingredient of the Standard Model But: the Standard Model cannot be the ultimate theory The Standard Model does not include gravity breaks down at the latest at M Planck GeV Hierarchy problem : M Planck /M weak How can two so different scales coexist in nature? Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.5

12 Higgs: last missing ingredient of the Standard Model But: the Standard Model cannot be the ultimate theory The Standard Model does not include gravity breaks down at the latest at M Planck GeV Hierarchy problem : M Planck /M weak How can two so different scales coexist in nature? Via quantum effects: physics at M weak is affected by physics at M Planck Instability of M weak Would expect that all physics is driven up to the Planck scale Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.5

13 Higgs: last missing ingredient of the Standard Model But: the Standard Model cannot be the ultimate theory The Standard Model does not include gravity breaks down at the latest at M Planck GeV Hierarchy problem : M Planck /M weak How can two so different scales coexist in nature? Via quantum effects: physics at M weak is affected by physics at M Planck Instability of M weak Would expect that all physics is driven up to the Planck scale Nature has found a way to prevent this The Standard Model provides no explanation Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.5

14 Hierarchy problem: how can the Planck scale be so much larger than the weak scale? Expect new physics to stabilise the hierarchy Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.6

15 Hierarchy problem: how can the Planck scale be so much larger than the weak scale? Expect new physics to stabilise the hierarchy Supersymmetry: Large corrections cancel out because of symmetry fermions bosons Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.6

16 Hierarchy problem: how can the Planck scale be so much larger than the weak scale? Expect new physics to stabilise the hierarchy Supersymmetry: Large corrections cancel out because of symmetry fermions bosons Extra dimensions of space: Fundamental Planck scale is TeV (large extra dimensions), hierarchy of scales is related to a warp factor ( Randall Sundrum scenarios) Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.6

17 Supersymmetry (SUSY) Supersymmetry: fermion boson symmetry, leads to compensation of large quantum corrections Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.7

18 The Minimal Supersymmetric Standard Model (MSSM) Superpartners for Standard Model particles: [ u,d,c,s,t,b ] [ũ, d, c, s, t, b ] L,R [ e,µ,τ ] L,R L,R [ẽ, µ, τ ] L,R [ νe,µ,τ ] [ νe,µ,τ ] L Spin 1 2 L Spin 0 g W ±,H ± }{{} γ,z,h 0 1,H 0 2 }{{} Spin 1 / Spin 0 g χ ± 1,2 χ 0 1,2,3,4 Spin 1 2 Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.8

19 The Minimal Supersymmetric Standard Model (MSSM) Superpartners for Standard Model particles: [ u,d,c,s,t,b ] [ũ, d, c, s, t, b ] L,R [ e,µ,τ ] L,R L,R [ẽ, µ, τ ] L,R [ νe,µ,τ ] [ νe,µ,τ ] L Spin 1 2 L Spin 0 g W ±,H ± }{{} γ,z,h 0 1,H 0 2 }{{} Spin 1 / Spin 0 g χ ± 1,2 χ 0 1,2,3,4 Spin 1 2 Two Higgs doublets, physical states: h 0,H 0,A 0,H ± Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.8

20 The Minimal Supersymmetric Standard Model (MSSM) Superpartners for Standard Model particles: [ u,d,c,s,t,b ] [ũ, d, c, s, t, b ] L,R [ e,µ,τ ] L,R L,R [ẽ, µ, τ ] L,R [ νe,µ,τ ] [ νe,µ,τ ] L Spin 1 2 L Spin 0 g W ±,H ± }{{} γ,z,h 0 1,H 0 2 }{{} Spin 1 / Spin 0 g χ ± 1,2 χ 0 1,2,3,4 Spin 1 2 Two Higgs doublets, physical states: h 0,H 0,A 0,H ± General parametrisation of possible SUSY-breaking terms free parameters, no prediction for SUSY mass scale Hierarchy problem expect observable effects at TeV scale Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.8

21 How does SUSY breaking work? Exact SUSY m e = mẽ,... SUSY can only be realised as a broken symmetry Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.9

22 How does SUSY breaking work? Exact SUSY m e = mẽ,... SUSY can only be realised as a broken symmetry MSSM: no particular SUSY breaking mechanism assumed, parameterisation of possible soft SUSY-breaking terms relations between dimensionless couplings unchanged cancellation of large quantum corrections preserved Most general case: 105 new parameters Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.9

23 How does SUSY breaking work? Exact SUSY m e = mẽ,... SUSY can only be realised as a broken symmetry MSSM: no particular SUSY breaking mechanism assumed, parameterisation of possible soft SUSY-breaking terms relations between dimensionless couplings unchanged cancellation of large quantum corrections preserved Most general case: 105 new parameters Strong phenomenological constraints on flavour off-diagonal and CP-violating SUSY-breaking terms Good phenomenological description for universal SUSY-breaking terms ( diagonal in flavour space) Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.9

24 Simplest ansatz: the Constrained MSSM (CMSSM) Assume universality at high energy scale (M GUT, M Pl,... ) renormalisation group running down to weak scale require correct value of M Z CMSSM characterised by m 2 0, m 1/2, A 0, tanβ, sign µ CMSSM has been the favourite toy for both theorists and experimentalists so far CMSSM is in agreement with the experimental constraints from electroweak precision observables (EWPO) + flavour physics + cold dark matter density +... Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.10

25 SUSY-breaking scenarios Hidden sector : Visible sector: SUSY breaking MSSM Gravity-mediated : SUGRA Gauge-mediated : GMSB Anomaly-mediated : AMSB Gaugino-mediated... SUGRA: mediating interactions are gravitational GMSB: mediating interactions are ordinary electroweak and QCD gauge interactions AMSB, Gaugino-mediation: SUSY breaking happens on a different brane in a higher-dimensional theory Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.11

26 ÜØÖ ËÑ ÐÐ Ñ Ò ÓÒ ÜØÖ Ä Ö Ñ Ò ÓÒ Models with extra dimensions of space Ö Ò Ô Ø Ñ Ê Ö Ú ØÓÒ Ö Ò ¹ÛÓÖÐ È ØÙÖ Ã ÐÙÞ ¹ÃÐ Ò È ØÙÖ Hierarchy between M Planck and M weak is related to the volume or the geometrical structure of additional dimensions of space observable effects at the TeV scale Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.12

27 Gravity in a warped spacetime geometry [L. Randall, LHC2TSP Workshop 11] Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.13

28 Phenomenological consequences of extra dimensions The wave function of a free particle must be 2πR periodic momentum is quantised Looks in 4-dim like a series of new, more massive partners associated with each known particle: Kaluza Klein tower Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.14

29 Phenomenological consequences of extra dimensions We may be trapped on a (3 + 1)-dimensional brane in a higher-dimensional space-time, while gravity can enter the extra dimensions Extra dimensions could be large, even infinite Could explain the apparent weakness of gravity in our 4-dimensional world At the LHC, gravitons could be emitted into the extra dimensions missing energy signals If gravity is strong at the TeV scale, particle collisions at the LHC could form mini black holes Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.15

30 Physics of electroweak symmetry breaking What is the mechanism of electroweak symmetry breaking? Standard Model (SM), SUSY,... : Higgs mechanism, elementary scalar particle(s) Strong electroweak symmetry breaking: a new kind of strong interaction Higgsless models in extra dimensions: boundary conditions for SM gauge bosons and fermions on Planck and TeV branes in higher-dimensional space New phenomena required at the TeV scale Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.16

31 Higgs phenomenology: SM and beyond Standard Model: a single parameter determines the whole Higgs phenomenology: M H Branching ratios of the SM Higgs: dominant BRs: M H < 140 GeV: H b b M H > 140 GeV: H W + W,ZZ Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.17

32 Production of a SM-like Higgs at the LHC SM Higgs production at the LHC: Dominant production processes: gluon fusion: gg H, weak boson fusion (WBF): q q q q H q g g t t t H q q W W + q H Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.18

33 Constraints on the SM Higgs from electroweak precision data Indirect constraint on M HSM, no direct search limits included in the fit July 2011 m Limit = 161 GeV [LEPEWWG 11] Theory uncertainty α had = α (5) ± ± incl. low Q 2 data χ Excluded m H [GeV] Preference for a light Higgs, M HSM < 161 GeV, 95% C.L. Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.19

34 Higgs physics beyond the SM In the SM the same Higgs doublet is used twice to give masses both to up-type and down-type fermions extensions of the Higgs sector having (at least) two doublets are quite natural Would result in several Higgs states Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.20

35 Higgs physics beyond the SM In the SM the same Higgs doublet is used twice to give masses both to up-type and down-type fermions extensions of the Higgs sector having (at least) two doublets are quite natural Would result in several Higgs states Many extended Higgs theories have over large part of their parameter space a lightest Higgs scalar with properties very similar to those of the SM Higgs boson Example: SUSY in the decoupling limit Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.20

36 Higgs physics beyond the SM In the SM the same Higgs doublet is used twice to give masses both to up-type and down-type fermions extensions of the Higgs sector having (at least) two doublets are quite natural Would result in several Higgs states Many extended Higgs theories have over large part of their parameter space a lightest Higgs scalar with properties very similar to those of the SM Higgs boson Example: SUSY in the decoupling limit But there is also the possibility that none of the Higgs bosons is SM-like Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.20

37 Higgs physics in Supersymmetry Simplest extension of the minimal Higgs sector: Minimal Supersymmetric Standard Model (MSSM) Two doublets to give masses to up-type and down-type fermions (extra symmetry forbids to use same doublet) SUSY imposes relations between the parameters Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.21

38 Higgs physics in Supersymmetry Simplest extension of the minimal Higgs sector: Minimal Supersymmetric Standard Model (MSSM) Two doublets to give masses to up-type and down-type fermions (extra symmetry forbids to use same doublet) SUSY imposes relations between the parameters Two parameters instead of one: tan β v u vd, M A (or M H ±) Upper bound on lightest Higgs mass, M h (FeynHiggs): [S. Heinemeyer, W. Hollik, G. W. 99], [G. Degrassi, S. Heinemeyer, W. Hollik, P. Slavich, G. W. 02] M h < 130 GeV Very rich phenomenology Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.21

39 Indirect prediction for Higgs mass in SM and constrained SUSY models (CMSSM / NUHM1) from precision data χ 2 fit for M h, without imposing direct search limits 4 SM CMSSM SM NUHM Δχ 2 2 Δχ Excluded m H [GeV] Excluded m H [GeV] M CMSSM h = 108 ± 6 GeV M NUHM1 h = GeV Accurate indirect prediction; Higgs just around the corner? Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.22

40 BSM Higgs phenomenology Large enhancement / suppression of standard search channels possible Example: large enhancement of H bb coupling large suppression of BR(h γγ), BR(h WW ),... New channels, different phenomenology: Experimental evidence for dark matter if dark matter particle is lighter than M H /2 large branching fraction into invisible particles large suppression of all other BRs Higgs production in decays of BSM particles h i h j h j decays Higgs radion mixing,... Higgses with nearly degenerate masses: large interference effects, resonance-type behaviour possible Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.23

41 MSSM with complex parameters: a very light SUSY Higgs? MSSM with CP-violating phases (CPX scenario): Light Higgs, h 1 : strongly suppressed h 1 V V couplings Second-lightest Higgs, h 2, possibly within LEP reach (with reduced V V h 2 coupling), h 3 beyond LEP reach Large BR(h 2 h 1 h 1 ) difficult final state tanβ 10 m t = GeV (b) Excluded by LEP [LEP Higgs WG 06] 1 CPX Theoretically Inaccessible m H1 (GeV/c 2 ) Light SUSY Higgs not ruled out! Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.24

42 A light Higgs in SUSY cascades Example: NMSSM scenario, light CP-even Higgs, 20 GeV < M h1 < 110 GeV, in agreement with all search limits (large singlet component) µ eff = 200 GeV, M 1 = 300 GeV, M 2 = 600 GeV M SUSY = 750 GeV, m g = 1 TeV Higgs production in chargino and neutralino decays in SUSY cascades... q q χ 0 i q χ0 1 h k q χ 0 1 b b g g q gq χ 0 i gq χ 0 1h k gq χ 0 1b b Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.25

43 Results for b b jet invariant mass distribution: SUSY signal, SUSY background, SM t t background (grey) L = 5 fb 1, M h1 40 GeV [O. Stål, G. W. 11] s = 7 TeV s = 14 TeV Events / 10 GeV L = 5 fb 1 Events / 5 GeV L = 5 fb M b b (GeV) Signal over background ratio looks encouraging h 1 peak and Z peak visible M b b (GeV) We could get a signal for SUSY + Higgs at once Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.26

44 How to infer the underlying physics from the A Higgs or not a Higgs? experimental signatures? Fundamental or composite? SM, MSSM or beyond? Is there other new physics; what is it? How does the observed new physics fit into the global picture (ew precision observables, flavour physics,... )?... Intense effort will be needed to identify the nature of electroweak symmetry breaking Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.27

45 Higgs searches: what did we learn so far? ATLAS SM Higgs search: combined upper limit normalised to the SM expectation (left) and observed result vs. expectation for a SM Higgs signal (right) [ATLAS Collaboration 11] 95% CL Limit on σ/σ SM ATLAS Preliminary Observed Expected ± 1 σ ± 2 σ CLs Limits -1 Ldt = fb m H [GeV] s = 7 TeV 0 p ATLAS Preliminary Observed Expected -1 Ldt = fb m H [GeV] s = 7 TeV 2σ 3σ 4σ 5σ Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.28

46 SM Higgs search: combined CMS results Combined confidence limit vs. expectation for a SM Higgs signal [CMS Collaboration 11] of SM Higgs hypothesis CL S CMS Preliminary, Combined, L int Observed Expected ± 1σ Expected ± 2σ s = 7 TeV -1 = fb Higgs boson mass (GeV/c 2 ) 90% 95% 99% Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.29

47 SM Higgs searches, high-mass region LHC excludes (at least at 90% C.L.) the range of 145 GeV < M HSM < 460 GeV Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.30

48 SM Higgs searches, high-mass region LHC excludes (at least at 90% C.L.) the range of 145 GeV < M HSM < 460 GeV Results from direct searches are in agreement with indirect constraints from electroweak precision data Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.30

49 SM Higgs searches, high-mass region LHC excludes (at least at 90% C.L.) the range of 145 GeV < M HSM < 460 GeV Results from direct searches are in agreement with indirect constraints from electroweak precision data A high mass Higgs? Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.30

50 SM Higgs searches, high-mass region LHC excludes (at least at 90% C.L.) the range of 145 GeV < M HSM < 460 GeV Results from direct searches are in agreement with indirect constraints from electroweak precision data A high mass Higgs? ATLAS sees an excess beyond M HSM = 460 GeV... Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.30

51 SM Higgs searches, high-mass region LHC excludes (at least at 90% C.L.) the range of 145 GeV < M HSM < 460 GeV Results from direct searches are in agreement with indirect constraints from electroweak precision data A high mass Higgs? ATLAS sees an excess beyond M HSM = 460 GeV... However: a heavy SM-like Higgs appears to be theoretically questionable Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.30

52 Prospects for SM Higgs searches in the high mass region [W. Murray, LHC2TSP Workshop 11] Large increase in coverage expected Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.31

53 SM Higgs search: ATLAS and CMS results in the low mass region Combined upper limit normalised to the SM expectation, low mass region [ATLAS Collaboration 11] [CMS Collaboration 11] 95% CL Limit on σ/σ SM 10 1 ATLAS Preliminary Observed Expected ± 1 σ ± 2 σ CLs Limits -1 Ldt = fb s = 7 TeV 95% CL limit on σ/σ SM 10 1 CMS Preliminary, s = 7 TeV -1 Combined, L = fb int Observed Expected ± 1σ Expected ± 2σ m H [GeV] Higgs boson mass (GeV/c Broad excess in low mass region Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.32 2 )

54 CMS results for SM Higgs searches: local p value and observed best-fit signal strength Local p-value [CMS Collaboration 11] 1σ 2σ CMS Preliminary, -1 s = 7 TeV, Combined, L = fb int Interpretation requires look-elsewhere effect correction 3σ 4σ Best fit σ/σ SM 2 ±1σ from fit Higgs boson mass (GeV/c With LEE: probability to see an excess at least as large as the one observed in the data is 0.4 Best compatibility with a SM Higgs for M HSM < 125 GeV Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.33 )

55 ATLAS results for SM Higgs searches: local p value vs. expectation for a SM Higgs signal [ATLAS Collaboration 11] 0 p 1 ATLAS Preliminary Observed Expected -1 Ldt = fb m H [GeV] s = 7 TeV 2σ 3σ 4σ 5σ Best compatibility with a SM Higgs for M HSM < 130 GeV Slight deficit w.r.t. SM expectation Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.34

56 SM Higgs search: Tevatron results, CDF + D0 CDF + D0 combined upper limit normalised to the SM expectation [CDF and D0 Collaborations 11] Tevatron Run II Preliminary, L 8.6 fb -1 95% CL Limit/SM 10 1 LEP Exclusion SM=1 Expected Observed ±1σ Expected ±2σ Expected Tevatron Exclusion Tevatron Exclusion July 17, m H (GeV/c 2 ) Broad excess in low mass region Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.35

57 Implications of SM Higgs searches Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.36

58 Implications of SM Higgs searches Search for SM Higgs has narrowed down to 114 GeV < M HSM < 135 GeV (+ high mass region) Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.36

59 Implications of SM Higgs searches Search for SM Higgs has narrowed down to 114 GeV < M HSM < 135 GeV (+ high mass region) In agreement with favoured region from electroweak precision data, compatible with SM and MSSM Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.36

60 Implications of SM Higgs searches Search for SM Higgs has narrowed down to 114 GeV < M HSM < 135 GeV (+ high mass region) In agreement with favoured region from electroweak precision data, compatible with SM and MSSM Broad excess in low mass region observed by ATLAS, CMS and the Tevatron Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.36

61 Implications of SM Higgs searches Search for SM Higgs has narrowed down to 114 GeV < M HSM < 135 GeV (+ high mass region) In agreement with favoured region from electroweak precision data, compatible with SM and MSSM Broad excess in low mass region observed by ATLAS, CMS and the Tevatron Note: H WW channel has very limited mass resolution Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.36

62 Implications of SM Higgs searches Search for SM Higgs has narrowed down to 114 GeV < M HSM < 135 GeV (+ high mass region) In agreement with favoured region from electroweak precision data, compatible with SM and MSSM Broad excess in low mass region observed by ATLAS, CMS and the Tevatron Note: H WW channel has very limited mass resolution What about a Higgs with M H 145 GeV with somewhat reduced σ BR(H WW ) compared to SM case? Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.36

63 Implications of SM Higgs searches Search for SM Higgs has narrowed down to 114 GeV < M HSM < 135 GeV (+ high mass region) In agreement with favoured region from electroweak precision data, compatible with SM and MSSM Broad excess in low mass region observed by ATLAS, CMS and the Tevatron Note: H WW channel has very limited mass resolution What about a Higgs with M H 145 GeV with somewhat reduced σ BR(H WW ) compared to SM case? Difficult to get sufficiently large BR(H WW ) in the MSSM, can better be accomodated in the NMSSM Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.36

64 CMS excess in H γγ search [W. Murray, LHC2TSP Workshop 11] 1.6σ excess at M H 140 GeV after taking into account LEE Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.37

65 Search for the heavy SUSY Higgs bosons H, A: limits in the M A tan β plane [ATLAS Collaboration 11] [CMS Collaboration 11] tanβ 60 All channels Observed CLs Expected CLs ± 1σ ± 2σ LEP -1 ATLAS 36 pb observed -1 ATLAS 36 pb expected s = 7 TeV, ATLAS Preliminary max, µ>0 m h -1 Ldt = 1.06 fb m A [GeV] Large coverage in M A tan β plane LHC + LEP start to close the region of very low M A Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.38

66 Search for the heavy SUSY Higgs bosons H, A: cross section limit from CMS [CMS Collaboration 11] Excess for M A > 200 GeV Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.39

67 However: has the acceptance for gg H,A be overestimated? [A. Nikitenko, LHC2TSP Workshop 11] Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.40

68 Fundamental or composite Higgs? Renewed interest in composite Higgs models, mostly from extra dimensions [N. Arkani-Hamed, A. Cohen, H. Georgi 01] [K. Agashe, R. Contino, A. Pomarol 05],... Composite Higgs: light remnant of a strong force Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.41

69 Fundamental or composite Higgs? Renewed interest in composite Higgs models, mostly from extra dimensions [N. Arkani-Hamed, A. Cohen, H. Georgi 01] [K. Agashe, R. Contino, A. Pomarol 05],... Composite Higgs: light remnant of a strong force Relation extra dimensions new strong forces? Correspondence (AdS/CFT): Warped gravity model Technicolour-like theory in 4D Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.41

70 Fundamental or composite Higgs? Renewed interest in composite Higgs models, mostly from extra dimensions [N. Arkani-Hamed, A. Cohen, H. Georgi 01] [K. Agashe, R. Contino, A. Pomarol 05],... Composite Higgs: light remnant of a strong force Relation extra dimensions new strong forces? Correspondence (AdS/CFT): Warped gravity model Technicolour-like theory in 4D Signatures at LHC: new resonances, W, Z, t, KK excitations Under pressure from electroweak precision tests Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.41

71 Effective field-theory description of a composite Higgs Agreement with electroweak precision data can be improved if there is a strongly interacting light Higgs, e.g. Little Higgs [N. Arkani-Hamed, A. Cohen, E. Katz, A. Nelson 02] Holographic Higgs [R. Contino, Y. Nomura, A. Pomarol 03], [K. Agashe, R. Contino, A. Pomarol 05],... Effective Lagrangian formalism for model-independent analysis of effects of a Strongly-Interacting Light Higgs (SILH) [G. Giudice, C. Grojean, A. Pomarol, R. Ratazzi 07] Specific pattern of modified Higgs couplings Strong W W scattering at high energies despite light Higgs Need precision measurement of Higgs couplings + test of longitudinal gauge-boson scattering Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.42

72 Strongly-Interacting Light Higgs: deviation of σ BR from the case of a SM Higgs [G. Giudice, C. Grojean, A. Pomarol, R. Ratazzi 07] Sensitivity at LHC: 20 40%, ILC: 1% ILC can test scales up to 30 TeV Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.43

73 Further prospects Prospects for searches for a 114 GeV SM-like Higgs: [W. Murray, LHC2TSP Workshop 11] 2011 data, when combined between ATLAS + CMS, should provide 2σ sensitivity down to M H = 114 GeV Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.44

74 Prospects for the signal significance [W. Murray, LHC2TSP Workshop 11] With 2012 data, ATLAS + CMS combined: expect sensitivity of at least 3.5σ Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.45

75 New physics addressing the hierarchy problem SUSY production cross sections at the LHC with 7 TeV: 10 Prospino2.1 σ tot [pb]: pp SUSY S = 7 TeV q g q q 10-2 χ 2o χ 1+ t 1t 1* q q * g g χ 2o g 10-3 ν eν e* χ 2o q LO m average [GeV] Highest cross section for gluino and squarks of the first two generations Squark and gluino couplings α s ; cross sections mainly determined by m q, g, small residual model dependence Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.46

76 SUSY searches at the LHC Dominated by production of coloured particles: gluino, squarks (mainly first two generations) Very large mass reach in the searches for jets + missing energy gluino, squarks accessible up to 2 3 TeV at LHC (14 TeV) Coloured particles are usually heavier than the colour-neutral ones long decay chains possible; complicated final states e.g.: g q q qq χ 0 2 qq ττ qqττ χ 0 1 Many states produced at once, difficult to disentangle Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.47

77 Pre LHC: Fit results for the CMSSM from precision data Comparison: preferred region in the m 0 m 1/2 plane vs. prospective CMS 95% C.L. reach for 0.1, 1 fb 1 at 7 TeV [O. Buchmueller, R. Cavanaugh, A. De Roeck, J. Ellis, H. Flächer, S. Heinemeyer, G. Isidori, K. Olive, P. Paradisi, F. Ronga, G. W. 10] ] 2 M 1/2 [GeV/c ~ τ LSP 1 tanβ = 10, A 0 = 0, μ > 0 CMS preliminary s=7 TeV Hadronic search, 95% C.L. curves L = 1000/pb L = 100/pb CMS-NOTE full CMSSM parameter space 68% C.L. 95% C.L. NO EWSB M 0 [GeV/c ] Best fit point was within the 95% C.L. reach with 1 fb 1 Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.48

78 SUSY search results for the CMSSM [ATLAS Collaboration 11] [CMS Collaboration 11] High sensitivity from search for jets + missing energy Previous best-fit point is excluded CMSSM starts to get under pressure Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.49

79 Interpretation of SUSY search result in "simplified model" "Simplified model": squarks of first two generations, gluino + massless neutralino (LSP), all other SUSY particles heavy [ATLAS Collaboration 11] Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.50

80 Limits for gluinos and squarks in simplified models, LSP mass varied between 0 and 200 GeV [CMS Collaboration 11] Large dependence on LSP mass Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.51

81 Excitement at SUSY 11 Stop production in gluino decays [ATLAS Collaboration 11] [GeV] 1 m~ t ~ g- ~ g + ~ ~ t-t production, 1-lepton, 4 jets >= 1 b-tag, m eff ~ ~ g t 1 +t, ATLAS Preliminary > 600 GeV ~ t χ 1 b+ 0 ± 0 m(χ ) = 60 GeV, m(χ ) 2 m(χ ) 1 m( ~ q 1,2 ) >> m( ~ g) 1 ~ 1 ± 1 g t ~ 1 t forbidden -1 Ldt = 1.03 fb, s=7 TeV CL s observed limit CL s expected limit Expected CL limit ±1σ s -1 Observed ATLAS (35 pb ) -1 Expected ATLAS (35 pb ) 200 Reference point m~ g [GeV] Observed limit decreased with 30 more luminosity 1.2 σ excess in both electron and muon channels Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.52

82 Global fit in the CMSSM including 2011 LHC data (1 fb 1 ) and XENON100 results 68% and 95% CL contours, pre- and post-lhc [O. Buchmueller, R. Cavanaugh, A. De Roeck, M. Dolan, J. Ellis, H. Flächer, S. Heinemeyer, G. Isidori, D. Martínez Santos, K. Olive, S. Rogerson, F. Ronga, G. W. 11] Preferred region opens up, overall χ 2 worsened Shift towards higher mass scales, higher values of tan β Comparison: GMSB yields much larger splitting between coloured and colour-neutral part of the spectrum Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.53

83 Status of SUSY searches Search for jets (+ leptons) + missing energy Bounds on gluino and squarks of first two generations of O( TeV) Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.54

84 Status of SUSY searches Search for jets (+ leptons) + missing energy Bounds on gluino and squarks of first two generations of O( TeV) The constrained scenario CMSSM starts to get under some tension: direct search limits vs. (g 2) µ Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.54

85 Status of SUSY searches Search for jets (+ leptons) + missing energy Bounds on gluino and squarks of first two generations of O( TeV) The constrained scenario CMSSM starts to get under some tension: direct search limits vs. (g 2) µ Reduced sensitivity to compressed spectra Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.54

86 Status of SUSY searches Search for jets (+ leptons) + missing energy Bounds on gluino and squarks of first two generations of O( TeV) The constrained scenario CMSSM starts to get under some tension: direct search limits vs. (g 2) µ Reduced sensitivity to compressed spectra Limited sensitivity to 3rd generation squarks Hardly any direct constraints from the LHC on colour neutral SUSY particles up to now Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.54

87 SUSY searches: what next? [S. Padhi, LHC2TSP Workshop 11] Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.55

88 Search for dilepton resonances: ATLAS [ATLAS Collaboration 11] Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.56

89 Search for dilepton resonances: CMS [CMS Collaboration 11] Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.57

90 Search for dijet resonances: ATLAS [ATLAS Collaboration 11] Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.58

91 Search for dijet resonances: CMS [CMS Collaboration 11] Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.59

92 Search for the rare decay B s µ + µ Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.60

93 BR(B s µ + µ ): combined result from LHCb and CMS Very good agreement with SM expectation (so far) Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.61

94 Conclusions LHC has started the exploration of the new territory of TeV-scale physics Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.62

95 Conclusions LHC has started the exploration of the new territory of TeV-scale physics No discoveries yet Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.62

96 Conclusions LHC has started the exploration of the new territory of TeV-scale physics No discoveries yet Heavy SM Higgs is disfavoured, in agreement with constraints from electroweak precision physics Slight excess in the low-mass region Closing in on the SM Higgs Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.62

97 Conclusions LHC has started the exploration of the new territory of TeV-scale physics No discoveries yet Heavy SM Higgs is disfavoured, in agreement with constraints from electroweak precision physics Slight excess in the low-mass region Closing in on the SM Higgs BSM searches: limits on coloured states of new physics, heavy resonances,... SUSY: limits on gluino and 1st and 2nd gen. squarks Tension building up for CMSSM-like scenarios Little sensitivity so far to other parts of a possible SUSY spectrum (similarly for other kinds of new physics) Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.62

98 Conclusions LHC has started the exploration of the new territory of TeV-scale physics No discoveries yet Heavy SM Higgs is disfavoured, in agreement with constraints from electroweak precision physics Slight excess in the low-mass region Closing in on the SM Higgs BSM searches: limits on coloured states of new physics, heavy resonances,... SUSY: limits on gluino and 1st and 2nd gen. squarks Tension building up for CMSSM-like scenarios Little sensitivity so far to other parts of a possible SUSY spectrum (similarly for other kinds of new physics) There is much more to come the party has just begun! Physics prospects for the LHC, Georg Weiglein, UK HEP Forum Physics at the LHC, Abingdon, 09 / 2011 p.62