1. Non SUSY Searches at the Tevatron
Rocío Vilar, IFCA (CSIC-UC)
On behalf of the CDF and DØ collaborations
SUSY and higgs talks will be on friday
XXXIXth Rencontres de Moriond
QCD and Hadronic Interactions
La Thuile, 28 March- 3 April

2. Rencontres de Moriond, March 31st
Outline
ee/mm Analysis
Z’, Extra Dimensions, Technicolor, SUSY, etc.
em Analysis
eeg
Excited Leptons
e/m + Jets
Leptoquarks (First and Second generations)
Jets + Missing Tranverse Energy (MET)
Leptoquarks (All generations)
Jet + Missing Transverse Energy(MET)
Extra Dimensions
Conclusions
I will not talk about the tevatron detector performance because previous speakers have done that already, and I will show the most recent result although there are more results that I won’t have time to talk today.
Review the topics, say the signature and the search.
Rocío Vilar, IFCA/UC
Rencontres de Moriond, March 31st

3. Dilepton High Mass Analyses
Search for resonances in high invariant mass
Results can be interpreted under
many different models:
Z’ (E6, sequential, little higgs)
Large Extra Dimensions
Randall Sundrum
Technicolor
SUSY
Etc
CDF and DØ has slightly different approach:
CDF : Calculate the acceptances and resonances for 3 different spin assumption( 0,1,2) and applied to many models.
DØ: Calculate the acceptances and resonances for each specific model
This is a signature base analysis, they look at the dilepton data and compare with the SM prediction looking for bumps in the high mass, and the results could be interpreted under many models listed here. On the right plots, itg shown the invariant mass distributions; the top plot shows the invariant mass distribution of the dimuon collected with D0 detector, where the green histogram is background (mainly DY, QCD also EW and cosmics) and the red dots are the data; bottom plots shows the invariant mass distributions of the dielectron, where the solid histograms are the main backgrounds and the dots are the data. This plots has been done using the forward region of the CDf detector, both experiments are looking into this region to increase their acceptances but not limit has been set using it so far.
As you see there is no excess from the expectation so we can set upper limits at 95%C.L. D0 and CDF have a slightly different approach CDF calculates the acceptances for the different models based on differences on the spin particles and DO calculates the acceptances and resonances for each model.
Rocío Vilar, IFCA/UC
Rencontres de Moriond, March 31st

4. Dilepton High Mass(ee, mm)
Two lepton with Et(Pt)>25 GeV
at least one central lepton
DØ uses mass window cuts and counting experiment
CDF fit the Mll spectrum
DØ preliminary 200 pb-1
Upper limit 95% C.L.
780 GeV
CDF/DØ set limits for low-energy E6 models using dilepton events
CDF has interpreted this result in the Little Higgs model (littlest higgs model)
Predict a heavy neutral boson Zh decaying into dileptons
Relevant parameter is the mixing angle cotq
channel L
(pb-1)
ZI 95%C.L (GeV)
Zc 95%C.L (GeV)
Zy 95%C.L (GeV)
Zh 95%C.L (GeV)
CDF ee
200
570
610
625
650 mm
126
425
455
465
495 DØ
575
640
680
One of the particles they are sensitive at is the heavy Z, Z’. This particle is predicted in many models such as Grand Unification Theory, and its observation will be proved of new physics.
This analysis consider Z’ with standar model couplings, although there is not theoretical model for this, it is good for experimental comparisons. Then, they extend the analysis into the Grand unification theorist and low energy E6 models, where there are four Z’ models, which are just diferent values of the mixing angle.
The plots shows the experimental cross section limits times BR, times the acceptances done by D0 as a function of the Z’ mass, blue line. And the other curves are the theoretical cross sections for the SM-like Z’ (red curve) and the E6 Z’s. d0 set a limit of 780GeV (and CDF is 750GeV).
This table here shows the result for the different Z’ models in the E6 theory. CDf has done this search in the electron and muon chGeV.
CDF has also re-interpreted this results in the little higgs model. This model tries to explain the hierarchy problems and two additional heavy bosons appear when the symmetry is broken. In this model the cross section for the heavy boson depens on the mass and the cotangen theta .They have set limits on the neutral heavy bosons
In the two channel for cottheta =1, equals to 825 GeV. They can excluded a region in the parameter space of cottheta and z’ mass.
ee: MZ’h >825 GeV (cotq= 1.0)
mm:MZ’h >790 GeV (cotq= 1.0)
Rocío Vilar, IFCA/UC
Rencontres de Moriond, March 31st

5. Dilepton High Mass(ee,mm)
Large Extra Dimensions ADD (GRV convention)
Mpl2 = (Mpl|3+N|)N+2 )RN=Ms N+2 RN
N>=3 only tested at colliders
The cross section is parameterized in terms of
h= l/Ms4
CDF: 2 electron Et>25 GeV
Fit to the Mee spectrum
DØ: 2 EM objects(e/g) Et>25 GeV
2 m Pt>25 GeV
2D Fit to the Mll and cosq*
Both experiments has done a search for Extra dimensions model, in this case the large extra dimensions in the ADD model. Where here the size of the extra dimensions could be as large as 1 mm, so the fundamental planck,Ms, scale could be of the order of 1 TeV. In this case the gravity can only propagate in the extra dimension, that means that the Graviton can ony be seen by the interaction with the 3-brane. The graviton in the ED is equivalent to Kaluza-Klein tower, which the separtion of each state is of the order of 1/R of the order of 10-4 ev, that means that at the current energies it is a continuum.
The production of the graviton will affect the invariant mass distribution of the dielectron as well as the angular distribution of the two electron. We have seen that the mass ditribution doesn’t show anything and the costheta distribution is shown in this plots. The top shows the CDF data(dots) compare with the standar model expectation, and the bottom plot shows the D0 comparison. There are no excess so they can set upper limits.
So CDF reinterpret the result for the Z’ analysis but calculates the acceptances for this case and D0 search for electron and photons at the same time, requiring EM objects without specification, also the do a 2 dimensional fit Mee and costheta to se the lmits. They have also look at the muon channel for this search.
The summary of this search is shown in this table, where the best limit comes from D0 EM, 1.36 TeV when they combine with run I they get the best limit so far, 1.43 Gev DØ
CDF L
(pb)
95%C.L (TeV)
95%C.L
(TeV)
diEm
200
1.36
1.11
diEm ( I+II)
1.43 mm
100
0.880
Rocío Vilar, IFCA/UC
Rencontres de Moriond, March 31st

6. Dilepton High Mass(ee,mm)
CDF interpret as Randall-Sundrum graviton
1 highly curved extra dimension
Gravity localised in the ED
Excited Kaluza-Klein graviton
Decays to leptons
Relevant parameters: k/Mpl
CDF uses acceptances
from spin2 case
CDF has reinterpreted their results in another extra dimension model; Randall-sundrum model where here the space is curve and the hierarchy is generated by an exponential function of the radius of the compactified theory. So that implies that the graviton instead of being a continuum as before it is a resonaces of spin 2 with the mass and the width determine by this factor.
The main thing here is that the KK are unevenly separate and each state has a couple strength of the order of 1/TeV (which in ADD model the sum of all KK state has that strength).
The relevant parameter here is the k over planck scale, where k is a parameter of the order of plank scale which controls the degree of the curvature of space.
They use the spin 2 acceptances shown on the top plot as a function of the graviton mass. They are around 50% for masses above GeV. They set limit on the graviton mass for a k/Mpl = 0.1 of 625 Gev in the electron channel they set limits also on the muon channel. The can exclude a region in the parameter space of the graviton mass versus k/Mpl shown in this plot by a grey color.
Set upper limits at 95% C.L.
ee: MG >625 GeV (k/Mpl= 200 pb -1
mm:MG>475 GeV (k/Mpl = 126 pb-1
Rocío Vilar, IFCA/UC
Rencontres de Moriond, March 31st

7. Dilepton High Mass(ee,mm)
DØ has done a search for TEV-1 Extra dimensions
Chiral fermions in 3D
SM bosons propagates in extra d>0 dimensions, and are equivalent to KK towers with Masses
M2n= Mo2 + n2M2c
Gives rise to mixing among SM boson and the nth modes of W/Z
198 pb-1
First direct search
At 95%C.L Mc > 1.12 TeV
Indirect searches:
LEP: > 6.6 TeV; all: > 6.8 TeV
The last transparency about the same flavor dileptons analysis is a search done by D0 for another Extra dimensions model, TeV-1. Here the fermions remains in the 3-brane but the SM bosons are allowed to propagates through the extra dimensions. So the bosons are equivalent to the KK towers, where masses that are proportional to the sm boson masses. And it would be a mixing between the SM bosons and the bosons of each dimensions, because the KK will have the same quantum numbers than the SM bosons and they mixed to all the Zn boson to a series of mixing angles, being the lightest one the one observed at LEP, but the coupligs will be different due to the mxing angles.
They use the invariant mass distribution and the costheta to see any deviation from sM prediction, they don’t observed anything so they set limits doing a 2d fit. They set a limit on the compactification scale of the other of 1.12 Tev. It has being the first direct search. Indirect search from Lep shows the limit of 6.6 TeV and all experiment combined 6.8tev
Rocío Vilar, IFCA/UC
Rencontres de Moriond, March 31st

8. Rencontres de Moriond, March 31st
me Analysis
DØ has done model independent search in em channel
Search for an excess over the SM prediction in the kinematic space
Look at the Missing ET , sensitive to new Physics
Set upper limits at 95 % C.L.
L = 98 pb-1
1 electron Et>25 GeV
1 muon Pt>25 GeV
Good fiducial volume
0/1 jet
Rocío Vilar, IFCA/UC
Rencontres de Moriond, March 31st

9. Rencontres de Moriond, March 31st
eeg Analysis
CDF has done a search for excited electron, predicted in many compositeness models
Produce via contact or gauge mediated interactions
The cross section depends on e* mass and L
L = 200 pb-1
2 electron /g,
At least one Central electron
Expected ; observed: 3
first time search
Contact interaction:
At 95% C.L. Me*>889GeV (Me* = L)
Gauge mediated:
At 95% C.L. Me*>208GeV (Me*= L)
Rocío Vilar, IFCA/UC
Rencontres de Moriond, March 31st

10. Rencontres de Moriond, March 31st
Lepton+Jets analysis
Dominant at Tevatron
Color triplet bosons with lepton and barion numbers, and fraction charge
Predicted in several theories: GUT, technicolor, SUSY,etc
Assume LQ couples to lepton and quark of same generation
Pair produced at Tevatron
LQ decays:
LQ lq (l = e,m,t) b =1
LQ nq b = 0
b= BR(LQ lj)
30% increase in
cross section at RunII
Rocío Vilar, IFCA/UC
Rencontres de Moriond, March 31st

11. Rencontres de Moriond, March 31st
e+Jets Analysis
First generation LeptoQuarks
eejj channel (b=1)
Two isolated electron in fiducial region
Two jets
Remove events in the Z peak
S(Et(e1)+ Et(e2)+ Et(j1)+ Et(j2) )>450 GeV
enjj channel (b=0.5)
Isolated central electron
MET >30 GeV, DF(e,MET)>0.7˚
Mt(en)>130GeV
S(Et(e1)+ Et(e2)+ Et(j1)+ Et(j2) >330 GeV
DØ observe 0 events w/ 175 pb-1, expects 0.4±0.1
Upper limit at 95%C.L MLQ>238 GeV
DØ observe 2 events w/ 175 pb-1, expects 4.7±0.9
Upper limit at 95%C.L MLQ> 194 GeV
Rocío Vilar, IFCA/UC
Rencontres de Moriond, March 31st

12. Rencontres de Moriond, March 31st
m + Jets Analysis
Second generation LeptoQuarks
mmjj channel (b=1)
Two muons
2 jets
Mmm>15 (J/y,Y)
Remove events in the Z peak
S(Et(j1)+ Et(j2) ) > 85 GeV
S(Pt(m1)+ Pt(m2)) > 85 GeV
√ Sj(Et )2+ Sm(Pt)2>200 GeV
CDF observe 2 events w/~200 pb-1
CDF expects 3.15±0.17
Upper limit at 95%C.L
MLQ> 240 GeV (b=1)
Rocío Vilar, IFCA/UC
Rencontres de Moriond, March 31st

13. Jets + Missing Transverse Energy
All generation LeptoQuarks
nnjj channel (b=0)
2,3 jets (leading jets in central region)
MET>60 GeV
Jets + MET not aligned
80˚ <DF(j,j)<165˚
Veto on leptons
Observed 124 events w/ 198pb-1
Expects 118±14 events
Upper limit at 95%C.L
78< MLQ<117GeV
Rocío Vilar, IFCA/UC
Rencontres de Moriond, March 31st

14. Jet+Missing Transverse Energy
DØ has done a search Extra Dimensions
Graviton is produced recoiling against a jet or gluon
Monojet like topology
J1 > 150 GeV,
J2 < 50 GeV,
MET > 150GeV
D(Met,jet)> 30o
Observe 63 events; expect 100 ±6±7 in 85 pb-1
Signal Limit at 95% C.L.= 84 events (expected limit 128 ± 28 )
Includes large energy scale uncertainty
Both MC and Data scales
Efficiency: 20%
Background: +50% and –30%
Statistical theory
Kfactor=1
Rocío Vilar, IFCA/UC
Rencontres de Moriond, March 31st

15. Rencontres de Moriond, March 31st
Conclusions
Tevatron is delivering record luminosities
Detectors have collected ~200 pb-1 of good quality data until September 2003
Data analyzed with sensitivity to many models
Leptoquarks (first, second generations)
Z’ models (E6, Little Higgs)
Extra Dimension models (ADD, TeV-1, Randall-Sundrum)
Excited electrons
Technicolor
SUSY
Stay Tune for more to come from Tevatron soon!!!
Rocío Vilar, IFCA/UC
Rencontres de Moriond, March 31st

16. Rencontres de Moriond, March 31st
LQ summary
Rocío Vilar, IFCA/UC
Rencontres de Moriond, March 31st

17. Rencontres de Moriond, March 31st
Tevatron performaces
Record luminosity 6.8E31
3.9pb-1 integrated in a single store
First store w/ antiprotons from Recycler
Tevatron successes in early 2004:
Rocío Vilar, IFCA/UC
Rencontres de Moriond, March 31st

18. Dijet High Mass Analyses
L = 75 pb -1
At least 2 jets , |h|<2
Reduce background: Cosq*<2/3
Search for resonances in the
invariant mass of largest Et jets
spectrum.
sensible to new physics
Particle
95% C.L. GeV
Axion/Coloron
200<M<1130
Excited Quark
200<M<760
E6 diquark
280<M<420 W’
300<M<410
Technirho
260<M<640
Rocío Vilar, IFCA/UC
Rencontres de Moriond, March 31st

19. Rencontres de Moriond, March 31st
Dijet High Mass
Sensitivity to high
K/Mpl and MG mass
With the same invariant mass
Search for Randall-sundrum model
Exclude a region on the Mgraviton K/Mpl plane
Excluded:
jj: 220<MG<840 GeV (k/Mpl= 0.3)
Rocío Vilar, IFCA/UC
Rencontres de Moriond, March 31st

20. Rencontres de Moriond, March 31st
More ee analysis
Acceptance for
Spin 1
Acceptance for
Spin 0
ee invariant mass
Rocío Vilar, IFCA/UC
Rencontres de Moriond, March 31st

21. Searches in dileptons ( cont’d)
More ee
Rocío Vilar, IFCA/UC
Rencontres de Moriond, March 31st

22. Rencontres de Moriond, March 31st
Dielectron event
Mee = 371 Gev
Rocío Vilar, IFCA/UC
Rencontres de Moriond, March 31st