Search for Hidden Dimensions in Run I Tevatron Data

Sharon Hagopian Florida State University

for the DØ and CDF Collaborations

37th Rencontres de Moriond Electroweak Interactions and Unified Theories Les Arcs, Savoie, France March 9-16, 2002 Searches for the Effects of SUSY Search for Resonant Slepton Prod. Search for Stop Pairs →τ b τ b

Searches for the Effects of Large Extra Dimensions

Search in monojet +E/ T γ / Search in + ET (also gravitino and gen. limit) Supersymmetry • New symmetry between fermions and bosons • Predicts superpartners for all known particles • R-parity ≡(−1) 3B+L+2S +1 for SM, −1 for SUSY particles in models where R-parity is conserved

• R-parity__ violation in __ production or decay

λijk Li Lj Ek , λ'ijk Li Qj Dk Lepton number violating • Lightest SUSY particle ~ χ0 in gravity mediated models 1 ~ ~ ~χ0 → γ G in gauge mediated models - 1 G • mSUGRA -MSSM with assumptions about physics at the GUT scale

• Five parameters Parameter Description tan β Ratio of higgs vacuum expectation values sign(µ) Sign of Higgs mixing parameter

m0 common scalar mass

m1/2 common gaugino mass

A0 common trilinear coupling

Mtop also required DØ Search for Resonant Slepton λ Production in RPV mSUGRA ( ’211)

µ ± d µ ± u d • Assuming u λ ~ u µ~ ± dominant ’211 vµ m m – µ~ µ~ u LQD coupling χ~ χ~m 0 χ~ 1 0 • Search for 2 µ u d ± ± and 2 jet final m µ µ W state (94 pb-1) Initial Selection: two central jets two central muons 7-5-3-1 NN variables: µ µ µ µ E j1 + E j2 , p 1 + p 2 , M 1 , 2 E j1,j1 > 20 GeV T T T T inv T µ µ µ ∆ 1 , 2 ∆ 1 , jnn µ1,µ2 R , R , Sph., Aplan. pT > 20 GeV HT(jets)> 50 GeV Background:

Z+2jets tt WW Total Obs.

4.8 0.53 0.01 5.34±0.07 5 DØ Search for Resonant Slepton λ’ ) production in RPV mSUGRA ( 211

95% CL limit contour

After NN selection, expect 1.01±0.02 SM events. Observed: 2 events Signal: ~ 6 at contour CDF RPV SUSY Search for Stop Pairs decaying into τ b τ b

• Stop pairs are produced thru RPC • Assuming RPV only in the 3rd ~~ + →τ + +τ + + generation: t t X l b h b X λ' λ' i j k 333 in ijkLQ D in the superpotential →τ τ • Use Z l h with no jet as a calibration to cancel systematic errors: obs b (N~~ − N~~ ) / a~~ σ = σ ⋅ Br(Z →ττ )⋅ t t t t t t ~t ~t Z obs − b (NZ N Z ) / aZ Major SM Backgrounds: –Z, γ * (ττ) + jets –W (eν,µυ ) + jets –W (τυ) + jets – Diboson – Multijet CDF RPV SUSY Search for Stop Pairs Decaying into τ b τ b

Selections (106 pb-1):

50 CDF Preliminary (106 pb-1) 45 Events 40 OS data Z→ττ(MC) 35 +LS Data 30

0 01234567 Number of charged tracks in τ cone CDF RPV SUSY Search for Stop Pairs Decaying into τ b τ b Additional Selections: 2 τ MT(lepton,E//T) < 35 GeV/c HT(lepton, h,ET) > 70 GeV

2 -1 CDF Preliminary (106 pb ) CDF Preliminary(106 pb-1) OS data OS data ∼ 2 ∼ 10 2 2 10 2 t1(100GeV/c ) t1(100GeV/c ) +Z→ττ +Z→ττ

+QCD Events / 5 GeV +QCD

Events / 5 GeV/c +W(→lν)+jet 10 10

1 1

-1 -1 10 10 0 20406080100120 40 60 80 100 120 140 ⁄ τ ⁄ MT(e,ET) HT(e, h,ET) ≥ 2 jets: ET > 15 GeV

25 CDF Preliminary (106 pb-1) 22.5 Events OS data 20 Z→ττ 17.5 ∼ 2 +t1(100GeV/c ) 15 channel bkgd obs acc.% at 12.5 ~ = mt 120 GeV 10 7.5 e 1.92±0.18 0 3.18 5 2.5 µ 1.13±0.13 0 1.79 0 012345 Jet multiplicity CDF RPV SUSY Search for Stop Pairs Decaying into τ b τ b

10 2

CDF Preliminary (106 pb-1)

→ ∼∼ → τ+τ– → τ pp t1t1 bb l + 2 jets ∼ → τ+ B (t1 b) = 100% 1 t – – 1 t ∼∼ (pb) 2 σ 10 M∼ > 119 GeV/c t1 ↓ σ ∼ NLO: CTEQ4M, Q=M t1 95% C.L. combined e+µ upper limit 95% C.L. upper limit from e channel 95% C.L. upper limit from µ channel 60 70 80 90 100 110 120 130 ∼ 2 M t (GeV/c )

Conclusion: No signal found; limit is set. > 2 (ALEPH: m ~t 93 GeV/c ) Large Extra Dimensions Large Extra Dimensions resolve the hierarchy problem by reducing the quantum-gravity scale to ~TeV

SM – 3+1 dimensional brane Gravitons can propagate in extra dimensions

-1 2 -1 π n 2+n GN =Mpl replaced by GN = 8 R Md The radius of the compactified space (assumed to be a torus) is 1 R = (M / M )2/n. n π Pl d 8 Md For Md ~ 1TeV, we have 1.2×1012m n =1,  0.48 mm n = 2, R =  3.6 nm n = 3,  -12 Ref. Giudice, Rattazzi, Wells 9.7 ×10 m n = 4. Phys. B544, 3(1999) hep- ph/9811291 Signatures for Large Extra Dimensions at the Tevatron Real Gravitons

Monojets at hadron colliders

g q g g • Kaluza-Klein gravitons couple to the energy- momentum tensor, and G G g KK therefore contribute to q KK most SM processes

• Since gravitons can Single VB at hadron or e+e- colliders propagate in the bulk, from our perspective in V GKK (3+1) space-time, energy V V and momentum will appear not to be GKK GKK conserved in GKK GKK emission V Virtual Gravitons • Depending on whether Fermion or VB pairs at hadron or e+e- colliders the GKK leaves our brane or remains virtual, f f V collider signatures can GKK GKK include single photons/Zs/jets with missing ET,, or pair produced objects f f V DØ Search for Monojet Production by Real Graviton Emission Selection Cuts • Number of jets ≥ 1

•ET of the leading jet >150 GeV

•ET of the other jets < 50 GeV • Leading jet central, with good jet quality

•E/ T > 150 GeV • Reject events with isolated muons • Reject cosmic rays D0 Analysis Luminosity 78.8 pb-1 WZ background = 30.2 ± 4.0 QCD/cosmics = 7.8 ± 7.1 total background = 38.0 ±8.2 Data: # events = 38

Ref. Giudice, Rattazzi, Wells Phys. B544, 3(1999) hep- ph/9811291 DØ Monojet Production 30

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N = 4, MD > 698 GeV (840 GeV, DELPHI)

N = 6, MD > 632 GeV (580 GeV, DELPHI) γ CDF E/ T Motivation: Photons can tag invisible particles such as gravitino in SUSY and graviton in LED γ One high energy central + E/ T Selections: γ ηγ – ET > 15 GeV and | | < 1.0

– E/ T > 45 GeV .

- No jets with ET > 15 GeV

– No tracks with PT > 5 GeV/c – Reject cosmic ray events

11 events observed in 87 pb-1 of data

Backgrounds: • Cosmic Rays: 6.3 ± 2.0 •Zγ -> ννγ : 3.2 ± 1.0 • W -> eν: 0.9 ± 0.1 • prompt diphoton: 0.4 ± 0.1 •Wγ : 0.3 ± 0.1 • QCD (not used): 0.9 • Total: 11.0 ± 2.2 γ CDF ET •Search for superlight gravitino Model: hep-ph/9801329, Brignole, etc. derive an absolute lower limit on the

gravitino mass m3/2 and scale √ F= 3m3/2Mplanck of SUSY breaking → ~ ~γ Process: qq GG Result: F > 221 GeV -5 Past best limit: 217 GeV M3/2>1.17*10 eV γ (CDF jet + E//T, DELPHI +ET) •Search for Large Extra Dimensions Model: Arkani-Hamed, Dimopoulos, Dvali, PLB 429 → γ Process: qq Gkk

N = 4, MD > 549 GeV (840 GeV, DELPHI)

N = 6, MD > 581 GeV (580 GeV, DELPHI) Result: N = 8, MD > 602 GeV (411 GeV, L3)

≥ ε σ Gen. cross section limit: 112 fb acc. x x NP->γ +MET Hidden Dimensions Tevatron Outlook Other New Run I SUSY and LED Results Search for new physics in lepton + γ Search for RPV in µµ+4 jets mSUGRA search in e + jets Search for RPV resonant sleptons in eµ _ Search for stop in like sign t t Search for stop in eµ

Search for stop in jets +E/ T Extra Dimensions search in ee, γγ

More good physics to come from Run I data while we look forward to Run 2 results!