# Presentation: 050087

## New PhenomenaSearches at CDF

- New PhenomenaSearches at CDF

- Aron Soha
*(University of California at Davis)*
- For the CDF Collaboration
- February 19, 2006
- Lake Louise Winter Institute

## Introduction

- Lake Louise, Feb. 19, 2006

- Aron Soha, UC Davis

-  The Standard Model falls short on several key questions:

- Higgs

- Large Extra Dimensions

- SUSY

- Heavy Objects

- ???

- Do the forces unite?

- What is dark matter?  How about dark energy?

- What is the true nature of gravity?

- Do particles get mass from a SM Higgs field, or something more?

-  Answers may come through new phenomena:

## CDF at the Tevatron

- Lake Louise, Feb. 19, 2006

- Aron Soha, UC Davis

- Record initial luminosity
- at CDF = 1.8×1032 cm-2s-1

- CDF

- Fermilab complex:

-  p accumulation
-   ≤ 20.12 mA/hr

-  Electron cooling
-   of p beam

-  Routine operation of 2
-   p storage rings

- Silicon

- Drift Chamber

- 1.4T solenoid

- EM calo.

- Had. calo.

- Muons

## SM Higgs in h0  WW(*)

- Lake Louise, Feb. 19, 2006

- Aron Soha, UC Davis

- SM Higgs in h0  WW(*)

-  At Tevatron, single neutral h0 is dominant Higgs production

-  h0  WW is dominant decay for MHiggs > 135 GeV/c2

- Use W - e and W -  decay modes

- Use azimuthal angle between 2 leptons
- to separate h0WW from dominant SM
- background of WW production

- New result with 360 pb-1

## SM Higgs in h0  WW(*)

- Lake Louise, Feb. 19, 2006

- Aron Soha, UC Davis

- SM Higgs in h0  WW(*)

- WHebb
- D0 382 pb-1

- HWWll
- D0 299-325 pb-1

- WHWWW
- CDF 194 pb-1

- ZHbb
- D0 261 pb-1

- ZHbb
- CDF 289 pb-1

- WHWWW
- D0 363-384 pb-1

- WHlbb
-     CDF 319 pb-1

- h0WW(*)ll
- CDF 360 pb-1

- SM ggh0WW(*)

- SM WHWWW

- SM ZHZbb

- SM WHWbb

-  h0WW limit is
-   closest to SM pred.
-   (for higher masses)

- 95% CL limits on
- Cross-section × BR

- Standard Model
- Cross-section × BR

-  New channels on the way:  ZH production, with Z-ll and H-bb

-  Tool improvements:  better b-tagging, neural nets for sig. vs. bkg.

## Search For H++ H--

- Lake Louise, Feb. 19, 2006

- Aron Soha, UC Davis

- Search For H++ H--

-  Doubly charged, pair production

-  Lepton-flavor violating decay

- +

- e+

- -

- e-

- H++

- H--

- Z0/*

- q'

- q

- Reconstruct 3 or 4 isolated leptons

- ET+∑pT(leptons)>190 GeV and Z veto

- Fights hadronic (QCD) backgrounds

- Reduces remaining electroweak bkgs.

- Expected background:  0.25 events
- Observed in 350 pb-1:  0 events

- (ppH++H--)×Br2(H++e) < 73.5 fb
- m      > 115 GeV/c2

- HL

- ++

## Large Extra Dimensions (I)

- Lake Louise, Feb. 19, 2006

- Aron Soha, UC Davis

-  Interpretation for energetic jet + missing ET

-  Direct production of graviton:  qq  gG,  qg  qG,  gg  gG

-  Proposal for gravitons populating 4+n dimensional Bulk

- (Arkani-Hamed, Dimopoulos, Dvali, Phys Lett B429 1998)

- ET > 150 GeV

- ET > 120 GeV

- Standard Model Backgrounds:

- Z -  +jets (real ET, irreducible)
- W l +jets (ET from  or lost lepton)
- QCD (ET from mis-measured jets)

- 265 ± 30 events

- Observed in 368 pb-1 of data:

- 263 events

## Large Extra Dimensions (II)

- Lake Louise, Feb. 19, 2006

- Aron Soha, UC Davis

- Effective Planck scale MD:

- MPlanck2 ~ Rn MD2+n

- n   MD (TeV)    R (mm)

- 2    >1.16      <0.36

- 3    >0.98      <3.7×10-6

- 4    >0.90      <1.1×10-8

- 5    >0.85      <3.5×10-10

- 6    >0.83      <3.4×10-11

- 95% CL limits

-  Place lower limit on effective scale and upper limit on size

- (For K = NLO/LO = 1.3)

## Event Displays for L.E.D.

- Lake Louise, Feb. 19, 2006

- Aron Soha, UC Davis

- r- view:

- Unrolled calorimeter view:

- Shows EM calorimeter energy (purple)

- Hadronic calorimeter energy (blue)

- Highest ET event:

- ET = 390 GeV

- Jet ET = 384 GeV

- ET = 390 GeV

- Jet ET = 384 GeV

## Heavy Objects:  Z'

- Lake Louise, Feb. 19, 2006

- Aron Soha, UC Davis

-  Search for new physics in di-electron mass and cos(*)

- Drell Yan background dominates

- MZ'    > 855 GeV/c2 at 95% CL

- - Look for a peak in Mee and look for a distortion in cos(*)

- - Z' would interfere with the Z/* (just as Z and * interfere in SM)

- CDF Run II preliminary
-           L=448 pb-1

- CDF Run II preliminary
-           L=448 pb-1

- Total Standard Model:  115     events
- Observed in 448 pb-1:  120 events

- For Mee > 200 GeV/c2:

- +16
-  -19

- MC is normalized to luminosity

- Data more consistent with Z/*+bkgs
- than with Z/*/Z'+bkgs for many models

- (seq)

## Di-electron Sample

- Lake Louise, Feb. 19, 2006

- Aron Soha, UC Davis

-  Will use for di-electron new physics searches at high Mee

- Plots show range:  66 < Mee < 116 GeV/c2

- - central/central or central/plug, two electrons with ET > 25 GeV

- - Drell Yan MC normalized to Z peak region

- - Using 1.01 fb-1

- Same, but linear scale

## Heavy Objects in Dilepton+X

- Lake Louise, Feb. 19, 2006

- Aron Soha, UC Davis

-  Open to heavy quarks, b', t', extra dimensions, SUSY

-  Signature based search for anomalous dilepton+X events

- X ∈  { large event HT, large ET jets, b-quark jets, 3rd lepton, large ET, ... }

- CKM matrix structure   3 down-type iso-singlet right-handed quarks:

- QRQR production, with QR W/Z/H + u/d

- Q= 0.289 pb for 300 GeV quark

- 4.49×Q = 90% CL limit

- HT in e events (GeV)

- Events / 20 GeV

- (Apply first to Bjorken, Pakvasa, Tuan heavy quark model, hep-ph/0206116)

- HT = ET(e)+pT()+ET(jet)+ET

-  Dilepton(e) + ≥2 jets(ET>50 GeV)

- Control region:  HT < 200 GeV

- Signal region:  HT > 400 GeV

-  No events seen in 305 pb-1 of data

- Will soon update to >700 pb-1

- Expect:  0.802 ± 0.440 SM

- 0.526 ± 0.058 QQ

## ... or in High pT Z Bosons

- Lake Louise, Feb. 19, 2006

- Aron Soha, UC Davis

-  High pT Z  ee and Z  Will include W decays later

-  Looking for heavy objects decaying to Z bosons

- Could be heavy quarks, Z', sparticle, ...

- QRQR udWZ

- Will also later add requirements such as ET, photon, or b-quark jets

- ... or in High pT Z Bosons

-  Z pT agrees between data and
-     SM background (Monte Carlo)

- pT in events (GeV)

- Entries (GeV-1)

-  < 0.170±0.005 pb
- 95% CL limit, for 300 GeV quark

-  Limits obtained on differential
-   cross section of extra Z production
-   as function of pT

- Example, using signature of
- heavy quark model:

-  Z mass cut:  66 < Mll < 116 GeV/c2

## SUSY:  R-Parity Violating Stop

- Lake Louise, Feb. 19, 2006

- Aron Soha, UC Davis

-  Supersymmetric top (stop) quark pair production

- Decay:

- Backgrounds:

- Look for e/, h, and 2 jets

- Production:

- Same diagrams exist for scalar
- 3rd generation leptoquarks (LQ3)

- R-parity violating

- mstop > 155 GeV/c2

- Expected SM:  2.26        events
- Observed in 322 pb-1:  2 events

- +0.46
-  -0.22

- (Same limit applies to LQ3)

- Z+jets and QCD reduced using

- W+jets (jet fakes tau) reduced
- using transverse mass of  (lepton,ET)

- pT(lepton) + pT(h) + ET > 85 GeV

## Conclusions

- Lake Louise, Feb. 19, 2006

- Aron Soha, UC Davis

-  Some of the latest new phenomena results from CDF:

- Higgs

- Higgs in h0   WW(*) (most sensitive channel for higher masses)

- Search For H++ H-- (setting limits)

-  Numerous other results are headed your way this Winter!

- Large Extra Dimensions

- Setting limits on effective mass scale and radii

- Heavy Objects

- Z' (setting mass limit)

- Dilepton+X and high pT Z (broad searches for anomalous events)

- SUSY

- R-parity violating stop (setting mass limit)