Higgs Searches beyond the Standard Model at LHC (and at the B-factories) Michael Kobel TU Dresden...

Higgs Searches beyond the Higgs Searches beyond the Standard Model at LHCStandard Model at LHC (and at the B-factories)(and at the B-factories)

Michael KobelMichael KobelTU Dresden TU Dresden

DESY Seminars 26.6./27.6.2007DESY Seminars 26.6./27.6.2007

OutlineOutline

I.I. Status of LHC, ATLAS and CMSStatus of LHC, ATLAS and CMS

II.II. Beyond the Standard Model (SM) HiggsBeyond the Standard Model (SM) Higgsa.a. MSSM overviewMSSM overview

b.b. Additional Neutral HiggsesAdditional Neutral Higgses

c.c. Additional Charged HiggsesAdditional Charged Higgses

d.d. Invisible HiggsesInvisible Higgses

e.e. Strong Electroweak Symmetry BreakingStrong Electroweak Symmetry Breaking

Michael KobelMichael Kobel

TU Dresden TU Dresden

DESY Seminars 26.6./27.6.2007DESY Seminars 26.6./27.6.2007

L. Evans – 14.6.07, LHC Advisory Committee 3

I. LHC: Descent of the last magnet, 26 April 2007

30’000 km underground at 2 km/h!


LHC: Inner Triplet problem November 2006

During the pressure test of Sector 7-8 (25 November 2006) the

corrugated heat exchanger tube in the inner triplet failed by

buckling at 9 bar (external) differential pressure.

The inner triplet was isolated and the pressure test of the whole

octant was successfully carried out to the maximum pressure of

27.5 bar, thus allowing it to be later cooled down.

Reduced-height corrugations and annealing of copper near the

brazed joint at the tube extremities accounted for the insufficient

resistance to buckling.

New tubes were produced with higher wall thickness, no change in

corrugation height at ends, and e-beam welded collars to increase

distance to the brazed joint.

Installation of these tubes is proceeding in situ.


Inner Triplet repair, Point 5


General schedule

Engineering run originally foreseen at end 2007 now precluded by delays in installation and equipment commissioning.

450 GeV operation now part of normal setting up procedure for beam commissioning to high-energy

General schedule being reassessed, accounting for inner triplet repairs and their impact on sector commissioning

All technical systems commissioned to 7 TeV operation, and machine closed April 2008

Beam commissioning starts May 2008

First collisions at 14 TeV c.m. July 2008

Pilot run pushed to 156 bunches for reaching 1032 cm-2.s-1 by end 2008

No provision in success-oriented schedule for major mishaps, e.g. additional warm-up/cooldown of sector


.

.

LHC General co-ordination schedule, EDMS 102509, 12 June 2007

Operation testing of available sectors

12 23 34 45 56 67 78 81

Machine Checkout

Beam Commissioning to 7 TeV

Consolidatio

n

Interconnection of the continuous cryostat

Leak tests of the last sub-sectors

Inner Triplets repairs & interconnections

Global pressure test &Consolidation

Flushing

Cool-down

Warm up

Powering Tests

8DESY Seminars 26./27.6.2007 Michael Kobel, TU Dresden

CMS assembled upstairs, lowered in Nov 06- Feb 07

ATLAS assembled downstairsfinishing installing all sub-detector components before end 2007

biggest/outermost (muon spectrometer endcaps) andsmallest/innermost (pixel) detectors are last to be installed

ATLAS & CMS


ATLAS & CMS

Both: Ready for first collisions in time!ATLAS

CMS


II. Electroweak Symmetry Breaking in SM and beyond

Where does the mass come from?


The Electroweak Symmetry Breaking (EWSB)

Standard Model (SM) symmetry requires massless particles*something* has to break this symmetry at t~10-10 sec

A background Higgs field?

then, it must have excitations = Higgs Bosonscan be excited best by massive particles (Z, W, t, or b)

Minimal model: 1 SM Higgs-field and 1 neutral Higgs-BosonBut: many possible alternatives and extensions!


Possible Symmetry Breaking Mechanisms 　

SUSY(m)SUGRAGMSBAMSBMirageSplit SUSYRPV…

SUSY(m)SUGRAGMSBAMSBMirageSplit SUSYRPV…

Extra-Dimension

LED(ADD)Randall-SundrumUniversal ED(KK)…

Extra-Dimension

LED(ADD)Randall-SundrumUniversal ED(KK)…

Extended Gauge Symmetry

Little Higgs, Higgsless, Left-Right Symmetric Model

Higgs-Gauge Unification

Extended Gauge Symmetry

Little Higgs, Higgsless, Left-Right Symmetric Model

Higgs-Gauge Unification

Dynamical Symmetry BreakingStrong EWSB, Chiral Lagrangian, Technicolor, Composite Higgs, Top-quark Condensation

Dynamical Symmetry BreakingStrong EWSB, Chiral Lagrangian, Technicolor, Composite Higgs, Top-quark Condensation

J.Lykken, Physics at LHC (Vienna)

PrecisionEW dataPrecisionEW data

Ryuichi Takashima 2006


II. a. Minimal Supersymmetric Standard Model (MSSM)

More than 1 Higgs-Boson?


Minimal Supersymmetry: 3 neutral Higgs Bosons: h, H, A 2 charged Higgs Bosons: H+, H-

at tree level, 2 parameters : tan = v2/v1 and mA

Stephen Martin, hep-ph/97-09356

gMSSM = gSM

MSSM on tree level

t b/ W/Z

h cos/sin -sin/cos sin()

H sin/sin cos/cos cos()

A cot tan -----


MSSM at 2-loop level

Loop level (constrained MSSM):SUSY breaking parameters, assumed to be unified at some scale :

gluino mass and Higgs mass parameter Mğ and

SU(2) gaugino mass term unified at MGUT M2 at MEW

sfermion mass terms : unified at MEW Msusy at MEW

squark trilinear couplings : unified at MEW A at MEW

mixing parameter in the stop sector : Xt = At - cot

Total: 8 parametersmt=171.4 GeV measured

M2, Msusy, Mğ, and Xt chosen to define a “benchmark scenario” tan and mA free to vary

(tan[1, 60?] and mA[50, 1000]GeV)

Higgs MassesA ~ degenerate in mass with

h at low massesH and H± high masses

h mass < 130 GeV (all scenarios)

S.Heinemeyer in J.Ellis et al CERN-PH-TH/2007-012


Features ofLarge mA and mH:

h is SM-like w/ maximal mass

gMSSM = gSM

H/A/H± produced via Fermion-couplings!Large enhancement of SUSY-Higgs ~(tan)2 possible

Large tan: b- associated production

Small tan: t- associated production

Search strategies

t b/ W/Z

h 1 1 -1

H -cot tan 0

A cot tan 0


Can we see the additional Higgses?

good news:at least one Higgs boson observable for all parameters in all four MSSM benchmark scenarios

bad news: significant area where only lightest Higgs boson h is observablee.g. Higgs discovery, ATLAS prel., 300 fb-1

(M. Schumacher, hep-ph/0410112, ATL-com-phys-2004-070)


II. b. Additional Neutral Higgs Bosons

How to discover?


Basic 2 2 diagram Corresponding to b-pdf in ProtonDetails much more complex

Add 23, 22, and 21 w/o double counting

Solution: SHERPA MC generator w/ CKKW matchingbetween Matrix Element and Parton Shower contributionsJet fractions agree with analytic calculation (Harlander+Kilgore)

Example: full (down-type) leptonic modesb h/H/A b µ+µ-

b h/H/A b b ℓ+νν ℓ-νν

Main backgrounds (several 100 pb)tt (b)b µ+ν µ-ν tt (b)b ℓ+ν ℓ-ν

qZ ‘‘b‘‘µ+µ- qZ ‘‘b‘‘

Associate A/H production with b-quarks


Mass distributions

µ+µ-: excellent mass resolution ~ 3 GeVstill not sufficient to separate h/A/H

course mass resolution ~ 40 GeVneed collinear approximation of tau decay

tan mA=132 GeV

tan mA=150 GeV

M.Warsinsky, Ph.D.thesisDresden, 2007

J.Schaarschmidt, Dipl.thesisDresden, 2007


Expected sensitivity

Best tan reach: H/A ℓhad(CMS Physics TDRCERN/LHCC 2006-021)

Large tan H/A µµ mode:

Measure tan via Higgs width


Additional Charged Higgs Bosons

New input from b-physics!


H±, theory

Mass and Couplings:mH±

2 = mA2 + mW

2 in MSSM w/ negligible radiative corrections

No coupling to W, ZTwo fermionic couplings dominant:

Minimum tb coupling at tan √(mt / mb ) ≈ 7


LEP Limits

Direct LEP limits for e+e- H+H- stop at ~mW due to W+W- backgr.

MSSM: BR(H±) dominant for mH± < mt mH± >~ 85 – 89 GeV

LEP direct H± limits:Relevant in non-SUSY 2-Higgs Doublet Models (2HDM)Marginal in MSSM, since mH±

2 = mA2 + mW

2 anyway


Newly developping constraints from b-decays

Gino Isidori, 3rd Workshop: Flavour in the Era of the LHC, 2006

Well defined pattern for exp. observables Starting to give useful constraintsMost limits in literature for 2HDM !No systematic studies for MSSM yet (too many param.!)


Shape functionKineticKagan-Neubert

O.L.Buchmüller, H.U. Flächerhep-ph/0507253, PRD73 (2006) 073008

SM prediction from Heavy Quark Effective Theory

Comparison with experiment involves extrapolation in Evia measured spectral moments

2 new NNLO calculations 2006: Misiak et al, Becher & Neubert

SUSY contributions via charged Higgs (also in 2HDM) stop loops (dep. on mt)

Radiative bsPenguins: Theory

~


Huge Photon backgrounds:from and (veto)from qq continuum (B-ID)

Major players:BABAR (hep-ex/0607071):

(3.94±0.31±0.36±0.21)×10-4

stat syst modelBELLE, CLEO, (LEP)

Radiative bsPenguins: Experiments

-- kinetic… shape function

BELLE CLEO


Comparison to theory

Summary (O.Büchmüller, DPG Heidelberg, 2007)

Naive NNLO theory average: Rbs = BR(exp)/BR(theory) = 1.16 ± 0.12

allows 0-40% SUSY contribution on 95%CL


Leading-order H± contribution!

2HDM (W.S.Hou, PRD 48 (1993) 2342)

rBBR(2HDM)/BR(SM) =

MSSM (G.Isidori, P.Paradisi, hep-ph/0605012)

Gluino-induced corrections ((mg,mq)to down-type Yukawa couplings considerable for large tan

rBBR(MSSM)/BR(SM) =

B New Physics

222

2

)tan1(

H

B

m

m

2

0

2

2

2

)tan1

tan1(

H

B

m

m

both cases: A(H±) has opposite sign!suppression

|A(H±)| < |A(W±)|

(near-)cancellation|A(H±)| ~ |A(W±)|

(near-)compensation|A(H±)| ~ 2|A(W±)|

enhancement|A(H±)| > 2|A(W±)|

rB

tan

± ±

~ ~


B Experimental Signature


B First Observations

2.6

C.Bozzi, HCP2007


SM prediction dependent on fB|Vub|

Interpretation hampered by discrepancy |Vub|incl .vs. |Vub|excl

Inclusive BXul(4.52 ± 0.19exp ± 0.27theo)x10-3

Exclusive Bl(3.60 ± 0.10exp ± 0.50theo)x10-3

HFAG „Average“ 2006(4.10 ± 0.09exp ± 0.39theo)x10-3

CKM fit w/o |Vub| (H.Lacker, FPCP07) (3.63 ± 0.09)x10-3

Avoid |Vub| uncertainty: (G.Isidori, P.Paradisi, hep-ph/0605012)

Scale with Bd mixing dependence on |Vub / Vtd| (reduced)

= (0.99 ± 0.29exp ± 0.08B(Bd) ± 0.12|Vub/Vtd|)x10-3 (my update, using hep-ph/0703035 )

B Interpretation

Excl. Incl.


Overall MSSM Fit of b-constraints

G. Isidori, F. Mescia, P. Paradisi, D. Temes: hep-ph/07030351.01 < Rbs < 1.24 (1 sigma): blue lines

0.8 < R‘B < 0.9 (future guess!): black lines

current 1-sigma would be 0.7 < R‘B < 1.3

NB: 2nd solution for mH < 200GeV not shown!

B → μ+μ− < 8.0 × 10−8: allowed below green linemBs

= 17.35 ± 0.25 ps−1 : allowed below gray line

2 < aμ(exp− SM)/10−9 < 4 : purple lines

Dark Matter (~Bino) density: light blue forbidden

M˜q = 1.5 TeV AU = −1 TeVμ = 1.0 TeVM˜ℓ = 0.4

TeV

M˜q = 1.5 TeV AU = −1 TeVμ = 0.5 TeVM˜ℓ = 0.3

TeV


Two main production processes

for mH± < mt

gg t t bW bH±

for mH± > mt

bg tH± bW H±

Two main decay modesH± dominant for “small“ mH±

below 200 GeV (large tan 10)below 150 GeV (small tan )

H± tb,approaches for “large“ tan BR(tb)/BR() = (mb/m)2 ~ 6

H± at LHC

H±

±

95 130 170 215 310 mH±(GeV)

H±(f

b)

M. Schumacher, ATL-com-phys-2004-070

H±

t


H± tb

Signal: gb(b) tH±(b) t tb(b) Wb Wbb(b)Huge Background: gg tt+jet t t“b“ Wb Wb“b“ especially: gg tt+bb t tb(b) Wb Wbb(b)

CMS: Likelihood (kinematics, masses, b-tags)

CMS physics TDR (CERN/LHCC 2006-021):

Discovery reach only for large tan and ideal background knowledgealready small backg systematicsmake it invisible for low LHC Lumi

Discovery reach at 30 fb-1

H±

t


H± Signal: gb(b) tH±(b) t (b) Wb (b)

Huge Background: gg tt Wb W(b) Wb ℓ (b) especially: gg tt Wb W(b) Wb (b)

ATLAS: (B.Mohn, M.Flechl, J.Alwall, ATL-PHYS-PUB-2007-006) Cut selection with had Essential cut: (pt

, ptmiss) for high pt

(flat H± vs. boosted W from top)

tt ----------


For mH± < mt : coverage for all tan via tt bW bH± bW b

For mH± > mt : coverage for large tan via tH± bW

“Isidori-Paradisi“ region covered w/ 30-300 fb-1

Mass gap closedby new H± analysis

Intermediate tan (Hansen, Gollub, Assamagan, Ekelöf: hep-ph/0504216 )

Decay H± ±1,2

iℓ+nhas some coverage in an optimistic scenario:

Max BR(H± ±1,2

i)

Lowest possible m ℓ

H± Discovery reach (ATLAS)

M.Schumacher, ATL-COM-PHYS 2004-070

~


II.d. Invisible Higgs

going beyond SUSY


H Invisible?

In SM only small BR(hZZ) ~ 1-1.5% above 180 GeV

Beyond SM (BSM): Noticeable decay ratesMSSM: h,H Neutralinos, Gravitinos

Large part of interesting parameter space already excludedEnhanced in scenarios w/o Gaugino mass unification

Massive Neutrinos of 4th Generation (K.Belotzky et al., hep-ph/0210153)

Extra Dimension Modelsmixing with Kaluza-Klein scalars

“Stealthy Higgs“ (J.v.d.Bij, ZPC75 (1997) 17, hep-ph/0608245)

N-plet of SM Gauge-singlets φ coupling to Higgs via free coupling ω

Higgs invisible maybe dominant Higgs maybe very broad

Battaglia, Dominici, Gunion, Wells,hep-ph/0402062


Search at LEP (OPAL)

SignalHigh effciency

BackgroundSeparated via mass-

dependent likelihood

Systematics via signal- free control samples


LEP limits

Stealthy Higgs limits and general cross-section limitsDiplomarbeit A. Ludwig (Bonn/Dresden), OPAL Collab., Eur. Phys. J. C 49 (2006) 457


Search at LHC

Similar problems as for LEP:Need associated production with “visible” particlesNo mass peak, just excess of events

background estimation from data important

Combination of production channels might help to identify invisible object as a Higgs

Discovery/exclusion expressed in parameter BR(hinv)∙BSM / SM

exclusion/discovery with SM production impossible sensitivity for BR(hinv) = with SM production


ZH channel


ttH channel


qqH channel (VBF, WBF)


Current ATLAS expectations

Only qqH channel sensitiv to for all masses

Studies only done for narrow higgses in ATLASNeed update (full simulation, trigger,…)Extremely broad Higgses: ongoingCMS: all ongoing

F. Meisel et al.: ATL-PHYS-PUB-2006-009, 30 fb-1

qqHinv


Extra dimension interpretation

For large higgs-graviscalar mixing and low MD:

No visible Higgs discovery at LHC (green area)Instead: invisible Higgs in qqHFit from data possible

graviscalar mixing Number of extra dim ILC helps a lot!

Battaglia, Dominici, Gunion, Wells, hep-ph/0402062 and D.Dominici, hep-ph/0408087, based e.g. on S. Abdullin et al. CMS NOTE-2003/033.

qqH in

visi

ble

>5


II.e. Strong Electroweak Symmetry Breaking

Effective Chiral Lagrangian


Strong Electroweak Symmetry Breaking

ElectroWeak Symmetry Breaking:Unitarity violation in WLWL scattering at high energy

Standard Model solution

one light Higgs bosonBut: hierarchy problem in rad corr to Higgs mass

solution: new physics at TeV scale (SUSY, Extra Dimensions, LittleHiggs, etc.)

if no Higgs !?solutions: new strong interactions

TechnicolorCompositeness…

General Concept: Chiral Lagrangian Modellow energy effects through values of effective chiral couplingsDobado et al., Phys.Rev.D62,055011, terms of major importance:

Different choices for magnitude and sign of a4 and a5

correspond to different choices for the underlying (unknown) theory.

q1q’1

q2 q2

W W

WW


Chiral Lagrangian Model

The usual EWChL approach doesn’t respect unitarity.restored by applying different unitarization protocols e.g.

Inverse Amplitude Method (Padé)N/D protocol, K-Matrix etc.

unitarization procedure resonances.position and nature of resonances depend strongly upon the unitarisation procedure. (Butterworth et al., Phys.Rev.D65,096014)


WW Boson Scattering

PYTHIA modified to include the EWChL and to produce resonances for different parameters.Detector response using both fast and full simulators.


WW Boson Scattering Event Selection

Signal, σ<100 fb

Background, W( l)+jets: σ~60,000 fb, tt: σ~16,000 fb

high pT lepton

high ETmiss

Jet(s) with high pT and mjj ~ mW.

Little hadronic activity in the central region (|η|<2.5) apart from hadronic WTag jets at large |η|>2.5


Reconstructed resonances

S.Allwood, hep-ex/07052869, ATLAS preliminary


III. Summary

Higgs Constraints from B-physics emerging in MSSM bsin penguins

B at tree level

consistent pattern, even with aµ and Dark Matter

LHC sensitivity to additional SUSY Higgs Bosonsat large tan (neutral or charged Higgs)at low masses mH±

< mt (charged Higgs)

Backgrounds at LHC often overwhelmingneed background estimation from data

LHC also sensitive to alternative scenariosInvisible HiggsStrong electroweak symmetry breaking…

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Higgs Searches beyond the Standard Model at LHC (and at the B-factories) Michael Kobel TU Dresden...

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