6/22/20151 Search of New Phenomena at the Tevatron Carlos Sánchez For the DØ and CDF experiments IFAE - Barcelona

04/18/23 1

Search of New Phenomena at the Tevatron

Carlos SánchezFor the DØ and CDF

experiments

IFAE - Barcelona

04/18/23 Carlos Sánchez - IFAE 2

The FNAL Tevatron p-pbar collisions at a

C.M energy of 2 TeV Two experiments around

the ring: CDF and DØ

Large amounts of data collected Analysis on 200 – 400 pb-1

Run 2 goal: 4.4 – 8.5 fb-1

Energy frontier until the LHC turns on


CDF and DØ• Both detectors well understood and highly efficient• Extensive calorimeter, tracking and muon coverage


Looking For SUSY

Introduces many new particles. Multiple signatures available. Pair produced. Decay into SM partners

plus MET. No knowledge of how

EWKSB occurs theorists choose models. Huge parameter space to

explore. Very small cross

sections.

Looking for new physics with the same old tools: jets, leptons, MET, …


SUSY tri- and dilepton Searches

Classic tri-lepton SUSY signature:

Trilepton signature is one of cleanest SUSY signatures Chargino-Neutralino production Decay to WZ (or sleptons) + 2

LSP

Low SM background But also : Small x-section

Leptonic Br are enhanced if slepton masses are close to gaugino masses.

2 like-sign leptons signatures available


Selection Bkgnd expected

OBSERVED

ee+l 0.21±0.12 0

el 0.31±0.13 0

l 1.75±0.57 2

±± 0.64±0.38 1

e+l 0.58±0.14 0

+l 0.36±0.13 1

SUM 3.85±0.75 4

6 analyses:

-2l(l=e,,)+isolated track or

MET and topological cuts (Mll,,

MT)

Very clean signature


Chargino Neutralino

LimitsmSUGRA: M(X±) ≈ M(X0

2) ≈ 2M(X0

1)

• “3l-max”

• M(slepton) ≥ M(X02)

• No slepton mixing

• M(X±1) > 116 GeV

• “Heavy squarks”

• M(X±) ≈ M(X02) ≠ 3M(qP)

• M(X±1) > 128 GeV

• “Large m0”

•M(slepton) >> (X02, X±)

• No sensitivity

Testing above LEP limit for mSUGRA


Process

mSugra ee 0.5

Bkgnd Expected 0.16±0.07

OBSERVED 0

SELECTION:

-2 electrons + ( =e,)largeMET >15 GeV/c2

- 15<Mll<76, >106 GeV/c2

- ||< 160- Njets(20 GeV) <2

Chargino-neutralino in ee channel

(Work in progress)


Gluino and Squark Search

(mSUGRA)

Jets + MET

#jets(PT (GeV))

∑Ptjet

(GeV)

MET(GeV

)

Bkg. Expected

OBS

2 jets(60,50) 250 175 12.8±5.4

12

3 jets(60,40,25) 325 100 6.1±3.1 5

4 jets(60,40,30,25)

175 75 9.3±0.5 10

• 4j(gPgP): M0 = 500 GeV M(gP) = 233

GeV

• 3j(gPqP): M(gP) = M(qP) M(qP) > 333 GeV

• 2j(qPqP): M0 = 25 GeV M(qP) > 318

GeV

Extended mSUGRA LEP limits


Search for Gluinos and Squarks

• 254 pb-1 of data• Trigger: 2 jets + MET > 35 GeV • ≥ 3 jets (125, 75, 25 GeV)• MET > 165 GeV, HT > 350 GeV

• Expect 4.2 1.1 bkgnd events.• Expect 2.6 – 4.8 SUSY events.Observed 3 events in data


Sbottom Search

ntag Bkgnd Obs.

=1 16.4 ± 3.7 21

>=2

2.6 ± 0.7 4


Stop Search

Expected Observed

Pre-tag 105 ± 12 119

Tag (silicon) 8.3 ± 2.3 11

% 100)~ctBR( 011

~

GeV 40 )~M( 0

1 Selection: 2 jets + MET + lepton veto


Chargino-Neutralino in

CDF and D0 combined

result:m(±)>209

GeV/c2

Bkgnd Expect

Obs Limit m+

D0 3.7±0.6 2 195 GeV

CDF 0.3±0.1 0 167 GeV

GMSB: GD is LSP, stable

2 photons ET > 20(13) GeV MET > 40(45) GeV


Rp-Violation Searches

Have assumed Rp conservation No proton decay No flavor-violating decays LSP is stable: good dark

matter candidate What if Rp is not

conserved? Global symmetries are

theoretically shaky Introduce new terms in MSSM Can produce single sparticles No stable LSP: no dark matter

candidate, no missing energy.

Production

and decay

133 122


Rp-Violating Sleptons

• Resonant production

1.1±0.4 (Expected) 2 (Observed)

• Decay only

EXP OBS neutralin

o

chargino

0.6±1.

9

0.5±0.

4

1.0±1.

4

2

0

0

84

(GeV)

95

66

165

(GeV)

181

118

μμl

eel

eet

All improve the Run I results


Stop in Rp-Violating SUSY(I)

1 1 had lep,qq gg t t b b

Assume

BR(t1b) ~ 100% Search for :

selection: 1 (=e,m)+ 1+ 2 jets


Stop in Rp-Violating SUSY(II)

Limit: Stop > 129 GeV(same signature as 3rd gen. LQ)

e+ + SUM

Expect. BG

2.6±0.6 2.2±0.5 4.8±0.7

Observed 2 3 5


Search in High Mass Dileptons

• Relatively ‘clean’ channel

• Z0 peak as a calibration point

• Many models to explore:

Z’, TC, RS graviton, LED

compositeness, etc…

∫Ldt = 200 pb-1

ee

Z’SM 600 GeV

ee


Z´ Limits

ZI Zχ Zψ Zη

SM coupling SM Couplings ee ee+ CDF : 750 735 815 394 DØ: 780 680

E6 ZI Zχ Zψ Zη CDF: 610 670 690 715 (ee+) DØ: 575 640 650 680 (ee)

DØ: μμ

DØ: ee

CDF:


W´ Search in e Channel W’: additional charged

heavy vector boson Appears in theories based

on extension of the gauge group

Left-right symmetric models: SU(2)R WR

Assume the neutrino from W’ decay is light and stable.

signature:

High PT lepton + high MET

MC only


W´Search (cont.)MT Distribution of Data

highest MT event

MT = 524 GeV/c2

σ*B(W’ enu) limit: ~ 50 – 100 fb for M(W’) > 500 GeV/c2 at 95% CL.

Limit: M(W’SM )> 842 GeV/c2


LeptoquarksGUTS, Technicolor, Compositeness, RPV-SUSY assume an additional symmetry between leptons and quarks.

Carry both lepton (L) and baryon (B) numbersCouple to quark and lepton of the same generation.

At the Tevatron they are pair produced.

Selection:

high PT isolated

lepton(s)and/or MET + 2 jets.


1st, 2nd, and 3rd Generation LQ

channels: eejj, ejj, (jj)

channels: jj, jj, jj

D0: Run I, MLQ > 200

GeV/c2

CDF: Run II, MLQ > 224

GeV/c2

D0: Run I + II, MLQ > 256

GeV/c2

CDF: Run II, MLQ > 235 GeV/c2


Extra Dimensions (ED)

exchange

ee

jet(s)+ET

+ ET

G

G

g,q

g,q

g,q

g,q

f

f

jet

emission

• Alternatives to SUSY for solving the hierarchy problem (MEW << MPlanck ???)

• Several different models:

• Large ED

• TeV-1 ED

• Warped ED

Arkani-Hamed, Dimopoulos, DvaliPhys Lett B429 (98)

Dienes, Dudas, GherghettaNucl Phys B537 (99)

Randall, Sundrum Phys Rev Lett 83 (99)


Extra Dimensions (ED)

LED with ee &

Stadard Model

Signal predictio

nQCD

LED with

No deviation from SM predictions


Randall-Sundrum Graviton (ee + + )

Dileptons have largest acceptance at low mass while has largest acceptance at high mass:

BR(G→) = 2 * BR(G→ee)


Conclusions Delivered data at the Tevatron over 1 fb-1

CDF and DØ running efficiently Interesting regions of parameter space

(for many models) are now in reach Testing beyond LEP limits Improving Run I results

Many new exciting results from Tevatron experiments and more coming soon!

http://www-cdf.fnal.gov/physics/exotic/exotic.htmlhttp://www-d0.fnal.gov/Run2Physics/WWW/results/np.html


Backup slides


CDF Luminosity

Over 1 fb-1 delivered


Technicolor

SM Higgs

Technirho


“Mass Bump” Search Strategies

Perform general searches comparing data to expectation Determine spin dependent acceptance and .BR* Interpret the results according to many new models!

Spin-0: RPV sneutrinos Spin-1: Z’SM, E6 Z’, Little Higgs Z’, TC (rT, wT) Spin-2: RS graviton

l+

l-

l+

l-X? X?


Spin Dependence Acceptance

spin-0 spin-1 spin-2

Angular distribution and therefore acceptance of decay product depends on the spin of the decaying particle.

central-central

central-forward

above combined

central: || < 1.1forward: 1.1 < || < 3.6


*B Limits (ee and channels combined)

*Br(X ee) 95% CL limitee, combined limit

*Br(X ) 95% CL limit σ*Br limit: ~ 25 fb for all spins for the high mass region (MLL > 600 GeV)

Documents

6/22/20151 Search of New Phenomena at the Tevatron Carlos Sánchez For the DØ and CDF experiments IFAE - Barcelona