# Presentation: 679569

## Search for Physics Beyond the Standard Model at the  TeVatron

- Jean-François Grivaz
- (LAL-Orsay)
- for the CDF and DØ Collaborations

- SUSY-06 June 16, 2006

- J.-F. Grivaz

## Beyond the Standard Model:

- 	Enlarge the gauge group  Z’, W’
- (*)	Alternative EWSB mechanisms (TC, little Higgs)
- (*) 	Relate quarks and leptons  Leptoquarks
- 	Extend Poincaré  Supersymmetry
- 		and include gravitation (Supergravity)
- 	Increase the number of dimensions
- (*)	Repeat the history (compositeness)
- (*) = Not covered today (in 30’)

- The Standard Model:
- 	SU(3)c x SU(2)L x U(1)Y
- 	The Higgs mechanism
- 	Three generations of quarks and leptons
- 	The Poincaré group
- 	In a 4-dimensional space-time

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## At the TeVatron:

- p-pbar collisions at 1.96 TeV c.o.m. energy
- Peak luminosity:  > 1.7 E32 cm-2s-1
- Delivered: > 1.5 fb-1
- In this talk: 0.2 to 1.1 fb-1

- DØ: http://www-d0.fnal.gov/Run2Physics/WWW/results/np.htm

- CDF: http://www-cdf.fnal.gov/physics/exotic/exotic.html

- Unless there are good reasons, I’ll pick examples in either one.

- Still
- the energy
- frontier

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## New Gauge Bosons

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## Extra Gauge Bosons

- M(Z’-seq.) > 850 GeV

- (somewhat lower limits in)
- (canonical E(6) models)

- MT = M(electron-pT,missing-ET)

- M(W’-seq.) > 788 GeV

- e.g., W’ in L-R models                   Z’ within E(6) GUTs

- Beauchemin

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## Supersymmetry

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## SUperSYmmetry

- At such a conference, no “What is SUSY ?”, or “Why SUSY ?”

- Which SUSY ?

- More or less constrained MSSM, à la mSUGRA
- 	neutralino-LSP
- 	with or without R-parity violation
- Gauge Mediated SUSY Breaking
- 	gravitino-LSP and neutralino-NLSP
- Anomaly Mediated SUSY Breaking
- 	wino-LSP and long-lived chargino
- Split SUSY
- 	long-lived gluino

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## (m)SUGRA

- Two main search streams at the Tevatron:

- Squarks and gluinos   ******   **multijets** + **missing ET
-  large production cross sections
-  large experimental backgrounds

- Electroweak gauginos with leptonic decays (Trileptons)
-  low production cross sections
-  typically low leptonic branching ratios
-  clean experimental signature

- m0  m1/2  tan()  A0  sign()

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## Trileptons

-  Arise from chargino-neutralino
-    associated production
-  “Golden” SUSY signature but:
-    - low cross sections ( BR)
-    - soft leptons
-    - taus (at large tan)
-  Needs large integrated luminosity
-  Combine various final states

- (Also decays via W/Z exchange)

- General strategy (similar in CDF and DØ):
- Two isolated (rather soft) e or 
- Require some Missing ET ()
-  channel-dependent cuts (e.g. anti Z, )
-  An isolated third lepton or track (sensitive to ’s), or
-  Two same sign leptons
- Main backgrounds: DY, WW, WZ, W (+ a bit of bb and mis-ID)

- Strologas

- Hohlfeld

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## ...and in the end...

| CDF Analysis | Lumi
(pb-1) | Total predicted
Background | Observd data |
| --- | --- | --- | --- |
| ee,e,  | 710 | 6.801.00 | 9 |
|   +e/ 
(low-pT) | 310 | 0.130.03 | 0 |
| ee+track | 610 | 0.480.07 | 1 |
| ee + e/ | 350 | 0.170.05 | 0 |
|   +e/ | 750 | 0.640.18 | 1 |
|  e +e/ | 750 | 0.780.15 | 0 |

| DØ Analysis | Lumi (fb-1) | Total predicted Background | Observd data |
| --- | --- | --- | --- |
| ee+track | 1.2 | 0.820.66 | 0 |
| +track | 0.3 | 1.750.57 | 2 |
| e+track | 0.3 | 0.310.13 | 0 |
| SS  | 0.9 | 1.1  0.4 | 1 |
| e+track | 0.3 | 0.580.14 | 0 |
| +track | 0.3 | 0.360.13 | 1 |

- The results of the various channels are combined,
- “weighted” according to their sensitivity, with overlaps taken into account.

- Cross-section upper limits & mass lower limits within specific models.

- Missing ET
- in +e/

- Missing ET  pT(3)
- in ee+track

- ...and in the end...

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## Models = “favorably tweaked” mSUGRA

- m0 = 60 GeV
-  2-body decays enhanced ()
- s mixing on ( sL component)
-  decays to ’s enhanced ()

- Both CDF and DØ set ms = mse = ms

- m(sl) = m(20) + 
-  only 3-body decays ()
- s mixing off (no sL component)
-  decays to ’s = to e/ ()

- Some work ahead for the TEV-WG...

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## Generic squarks and gluinos

- Strong production ( Large cross sections ) of:
-  sq-sqbar and sq-sq 	  at least 2 jets + missing ET (sq  q)
-  gl-gl			  at least 4 jets + missing ET (gl  qq)
-  sq-gl			  at least 3 jets
- Cascade decays complicate the picture  model needed (mSUGRA)

- DØ	three analyses optimized for each of these processes
- 	reduces QCD to a negligible level
- CDF	3-jet analysis optimized mostly for m(sq)  m(gl)
- 	larger QCD background, estimated from control regions

- Main backgrounds:
-  Instrumental (QCD multijets with fake missing ET)
-  (W(missed lepton)+) +jets (also from ttbar)
-  (Z  ) +jets (irreducible)

- Martinez

- Bargassa

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## Main analysis cuts:

-  Data cleaning
-  Jet1,2(,3(,4)) pT
-  Missing ET
-  HT = sum of jets pT’s
-  Lepton veto
-  Angles (jet,missing ET)

| Analyses | Background 
expected | Events 
observed |
| --- | --- | --- |
| DØ  2 jets | 4.8  4.5 | 6 |
| DØ  3 jets | 3.9  1.5 | 4 |
| CDF  3 jets | 8.2  2.9 | 2 |
| DØ  4 jets | 10.3  2.4 | 10 |

- HT225 GeV

- (m(gl)=240 GeV)

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## You have seen or will see

- Mgl > 387 GeV (when Mgl~Msq)
- Mgl > 241 GeV & Msq > 325 GeV

-  other versions of this plot.

- CDF vs DØ differences:
-  371 vs 310 pb-1
-  tan = 5 vs 3 (little impact)
-  4 vs. 5 flavors (little impact)
- Theoretical uncertainty on
- the signal cross section:
-  CDF includes it as a systematic
-    uncertainty in the computation
-    of the cross section limit
-  DØ reduces instead the theoretical
-   cross section by its uncertainty
-   (more conservative): yellow band
- ...and CDF was a bit lucky.

- Some work ahead
- for the TEV-WG...

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## Stop

- A light stop can be expected:
- top-Yukawa impact in RGE

- First scenario considered by DØ:

- (relevant as long as m(st) < m(b)+m(W)+m())
- (in SUGRA, needs M1 < M2 at GUT scale)

-   1 c-jet (soft tag)
- + missing ET
- (optimized for
- various m(st),m())
- Main backgrounds: W/Z+jets

- + Large L-R mixing

- stop NLSP and  LSP
- with stc (FCNC)

- Bargassa

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## Stop

- Light sneutrino  st  b l s
- 2 leptons (+b-jets)
- + missing ET (s)
- (optimized for various m(st),m(s))

- Stop exclusion up to m(top)

- Second scenario considered by DØ:

- e and  final states analyzed
- Main backgrounds:
- Z at low mass, top at high mass

- e analysis:
- ST=pT(e)+pT()+missing ET
- with two signal examples

- Bargassa

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## Sbottom

- A light sbottom can be expected at large tan.

- DØ searched for sbottom pair production, with sbb
-    1 b-jet + missing ET (optimized for various m(sb),m())

- CDF searched for sbottom from
- decays of pair-produced gluinos:
-      gluino b sb (100%)
-     3/4 b-jets + missing ET
- With 156 pb-1, sbottom masses up to 240 GeV
- are excluded IF m(gluino) < 280 GeV (and m() = 60 GeV)

- Bargassa

- Martinez

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## R-parity violation

- Possible additional terms in the superpotential:

- With a  term, only RPC pair production, mostly + and 20,
- with (cascade) decays to LSP’s followed by RPV decays

- e.g.

-  4 charged leptons + missing-ET

- With a ’i11 term, also resonant production: e.g.

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## R-parity violation: ijk

- DØ: 121, 122, 133 considered
- Three trilepton searches combined:
- eee/	0.90.4  (background
- /e	0.40.1  (events	       0 candidate
- ee	1.31.8  (expected

- NN -ID validated with Z

- CDF also used clean four-lepton topologies:
- 0 candidate vs 0.0080.004 bg. expected

- For 133, ee most powerful
- at large tan and low m0:
- m(10) > 115 GeV
- for tan = 20, A0 = 0,
-   0 and m0 = 100 GeV

- Autermann

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## R-parity violation: ’ijk

- DØ: ’211 resonant production

- Reconstruct:
- m(smuon) = m(jj)
- m(10) = m(jj)

- No accumulation
- m(smuon) > 210 to 363 GeV
- for
- ’211 > 0.04 to 0.10
- (tan=5, A0=0 and  < 0)

- CDF: ’333 pair production

- Look for (e/)(hadrons) +2 jets

- 2 candidates vs. 2.30.5 bg.

- (Also LQ3)

- Autermann

- Martinez

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## Neutral Long Lived Particles

- DØ search motivated by 3 dimuon events in the NuTeV experiment
- Production and decay model: SUSY RPV with a small 122

- Look for displaced dimuon vertices
- (5 to 20 cm)
- Calibrate with Ks decays

- 0 candidate vs. 0.81.6 bg.

- Convert NuTeV
- (p-p at 38 GeV)
- to DØ
- (p-pbar at 1.96 TeV)

- (383 pb-1)

- Autermann

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## Charged Massive Stable Particles

- Long-lived charginos are expected in some AMSB models
- with a “wino-LSP” (small  – 10 mass difference)
- They would appear in DØ as slowly-moving muons
-  Make use of the time information of the muon system scintillators

- For a 150 GeV chargino:
- 0 candidates for 0.690.05 bg.

- Gershtein

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## Gauge Mediated SUSY Breaking

- In GMSB, the LSP is a light gravitino G
- A 10 NLSP decays into +G

- All backgrounds determined from data
- (fake photons from dijet events, We+/jet)

- pT() > 25 GeV  Missing ET > 45 GeV

- 4 candidates vs. 1.80.7 bg.

- “mGMSB Snowmass slope”
- (N=1, Mm = 2,   0, tan = 15)

- Signal dominated by 20 production
- m(10) > 120 GeV

-  Inclusive search by DØ
- for  + missing ET

- Gershtein

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## Stopped Gluinos

- In “Split-SUSY”, squarks are ultra-heavy  long-lived gluinos
- Such gluinos form R-hadrons which may stop in the DØ calorimeter.

- Backgrounds: beam and cosmic muons, measured in data.

- Strategy:
- look for a randomly oriented monojet in an otherwise empty event
- (diffractive trigger).

- After a while, they decay into a gluon + 10
- (q-qbar-10 is also possible).

- (A. Arvanitaki et al., arXiv:hep-ph/0506242)

- Excludes gluino masses
- up to 300 GeV

- Gershtein

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## Indirect limits from Bs

- SM: Bsis heavily suppressed

- SUSY: large enhancement

- Huge dimuon background
- Discriminate using
-  Decay length
-  Isolation
-  Pointing
- Normalize to B+J/ K+

- Limit at 95% C.L (780 pb-1):

**BR(B****s************) < 1. 10****-7**** **

- 1 candidate event selected
- in a 60 MeV mass window
- vs. 1.40.4 bg. expected

- CDF search:

- Carena

-  GeV

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## Extra Dimensions

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## Extra-dimensions

- ...come in many flavors: LED, TeV-1, UED, RS

- Two classes of models considered:
- ADD
- 		2 to 7 large (sub mm) EDs
- 		gravity propagates
- 			freely in the bulk
- 		KK excitations
- 			cannot be resolved
- RS
- 		one 5th (infinite) ED
- 			with warped geometry
- 		gravity is localized
- 			on a brane other than the SM
- 		KK excitations
- 			have spacings of order TeV

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## Large Extra Dimensions

- Two main search streams at the TeVatron:

- Real graviton emission
-    Apparent energy-momentum
-    non-conservation in 3D-space
-          “Monojets”
- Direct sensitivity to the
- fundamental Planck scale MD

- Virtual graviton exchange
- Modifies SM cross sections
- Sensitivity to the theory cutoff MS
- (MS expected to be  MD)

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## Monojets

- CDF search in 1.1 fb-1:

- Main selection cuts:
-  one high pT jet ( 150 GeV)
-   (soft jets from ISR are allowed)
-  isolated lepton veto
-  Missing ET away from jets
-  Missing ET  120 GeV

- Main background: (Z ) +jet
- Calibrated with (Zll and Wl) + jet
- QCD is negligible

- 779 events selected
- 819  71 expected

- Beauchemin

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## High pT dileptons & diphotons

- DØ search in 200 pb-1 combines ee and  to maximize the sensitivity

- Still world tightest limits:
- MS > 1.36 TeV
- MS >1.43 TeV w/DØ@Run I
- in the GRW formalism

- Fit of Data to SM+QCD+LED(MS)

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## Randall – Sundrum gravitons

- Here too, most of the sensitivity is in diphotons (BR = 2ee)

- DØ combined ee + 
- as for the LED search
-  doesn’t add much

- Two model parameters:
- Mass and coupling (/MPl)

- For /MPl = 0.1: M  785 GeV

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## Looking for the unexpected

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## Signature based searches

-  + X in 0.7 to 1 fb-1

- X=e	2 vs. 4.50.8
- X=	0 vs. 0.50.1
- X=	4 vs. 1.90.6

- l  + Missing ET in 0.3 fb-1

- l=e	25 vs. 19.83.2
- l= 	18 vs. 15.32.2

- (CDF Run I excess not confirmed)

- (Also multileptons + photon)

- CDF:

- Goncharov

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## Final remarks

- With a steadily improving collider performance
- there are still a number of years and fb–1 ahead of us
- for frontier physics at the TeVatron.

- CDF and DØ have now begun to explore
- clearly virgin territories.
- Already 1.3 fb-1 on tape, only partially deciphered
-  Expect many new results in the coming months

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## Back-up Slides

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## Slide 36

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## Slide 37

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## Stop decays in mSUGRA

- (tree level)

- (loop)

- m0 = 200 to 600 GeV (50 GeV step)
- m1⁄2 = 110 to 180 GeV (10 GeV step)
- A0 = –500 to –1000 GeV (100 GeV step)

- tan = 3 and 10 to 50 (10 step)
- Both signs of 

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