# Presentation: 268013

## High Mass DiphotonsBlessing

- Tracey Pratt
- 	Liverpool
- Ray Culbertson
- Fermilab

-  Motivation
-  Dataset &  Event Selection
-  Comparison of Background Expectation to Data
-  Limits on Randall-Sundrum model
-  Blessed Results (200 pb-1)
-  Updated results (345 pb-1)
-  Summary and Conclusions

**Main changes since pre-blessing**
** ****Removed COT-degraded data without Si**
** ****Added cos********* distributions**
** ****Added high mass integral table**

## Updating  Peaks to 345pb-1

- Currently 202pb-1 blessed in June
- primary blessing note: CDF Note 7024, June 2004
- 	http://home.fnal.gov/~pratt/Bless2004/Bless2004.html
- also relevant info (not blessed): CDF Note 6560, July 03
- update blessing note: CDF Note 7128
- 	http://home.fnal.gov/~pratt/Bless2004/Bless2004Update.html
- - public CDF note 7098

- Good demonstatration that COT-degraded data can be used
- → only expect slight change in efficiency and increase in background due to minor track loss for isolation variables

##  Data Sample

_**Event Selection**__ _
- 2 central  ET>15 GeV
- both isolated in calorimeter and COT
- good CES cluster
- Had/Em < 0.055 + 0.00045*E
- 0 or 1 low Pt track in cone around 

- Perform searches compare to bkdgs and apply to new physics models

- 	Sample			Runs		 pb-1
- 0 cdip0d, pre-shutdown      138425-168889	212
- 1 cdip0d, post-shutdown     175066-179096	  46
- 2 cdip0e, COT-degraded   179097-182840	  48
- 3 cdip0e, COT-recovered  182842-184456           39
- 	  Total 	  			           	345

- collected between 03/02 and 09/03

**Data Sample**

- cdip0d, cdip0e (diphoton 12/18) dataset
- 5.3.1 production
- stntupled with dev_242/531
- DQM v6 bits, require basic, CES, COT
- 	→removed CMU, CMP requirement,
- 	    since this was N/A for some new runs

## Event Selection

_**Event Selection**__ _
- _for ____ candiates signal sample_
- Require Standard Photon cuts V2.1
- _for ____ candiates sideband samples_
- Require looser cuts:
- 2 central  ET>15 GeV
- loose calorimeter isolation:
- (if Et<20.0: iso<0.15*Et, else iso<3.0+0.02*(Etc-20.0)
- track isolation: Sumof tracks Pt in cone 0.4 around < 5.0 GeV
- Had/Em < 0.125
- then slightly tighten these:
- Sideband
- Sideband + tighten iso to signal cut
- Sideband + looser iso cut (if Et<20.0: iso<0.2*Et, else iso<3.5)
- Sideband + N3d to signal cut
- Sideband + SumPt in cone of 0.4 to signal cut
- Sideband + 2nd CES to signal cut

## Data Statisitics

- Sample        candidates       Sideband
- 	0		2097		4217
- 	1		  458		  862
- 	2		  422		  854
- 	3		  362		  619
- Total		3339		 6552

- 	      High Mass Events
- Run/Event 	        Sample	Mass
- 166007/2285035	0	206.6
- 165435/446579		0	328.5
- 165271/ 2045232	0	404.9
- 179480/246457		2	247.9
- 181466/ 2729298	2	304.8

## Efficiency Checks

- Sample		Efficiency (%) from unbiased Z legs
- Prev.		81.5 ± 1.6
- 0			79.8 ± 1.3
- 1			77.2 ± 2.9
- 2			74.5 ± 3.2
- 3			80.1 ± 2.9

- Use lum-weighted:
- 	 79.0 %

- Events/Lum, norm to 1 for 202 pb-1
- Sample	  Trigger events   candidates   sideband   	Z peak
-      0		1		1	       1		    1
-      1		1.15	     1.01 ± 0.05  	0.94 ± 0.04    1.02  ± 0.09
-      2		0.97	     0.89 ± 0.05	0.89 ± 0.03    1.25  ± 0.10
-      3		0.97 	     0.94 ± 0.05 	0.80 ± 0.03    1.24  ± 0.11

- Reduce  efficiency by 6 %

## Total Efficiency

## Mass Plot

**5 high mass events**

- Same as blessed
- Bins of resolution

- highest 2 mass events are same as in previous blessed analysis (202 pb-1)

## Event Displays

## Event Displays

## Expected Diphoton Spectrum

**Search selection**
- 	2 isolated  ET>15 GeV, ||<1

-  - same as blessed
-   ** ****Standard Model** diphoton production estimated using Diphox (NLO), 	absolutely normalised
- 	mass spectrum corrected for efficiency from Pythia SM  prod.
-    **Fakes**: -jet and jet-jet
- estimated using sidebands

- - loosen  selection criteria
- - exclude tight events
-  apply various tighter cuts
-  fit to the spectrum

-    Normalised in the low mass region
-      ∫30 Ndata= ∫30 Ndiphox+∫30 NSB

- 100

- 100

- 100

## Mass Plot

- Same as blessed
- Bins of good statistics for comparision to BG

## Mass Plot

- Same as blessed
- 5 GeV bins

## Integral Mass Plot

**Integral Mass Plot**

**Mass N****data****  ****	****   ****	****	****   N****bkdg  ****   **
**Cut        ****	****   Total              Diphox  ****	**** Fakes**
**100   87      96.9      84.8 ****±**** 9.2 ****±****18.2     12.0 ****±  ****3.5 ****± ****6.3****150   21      30.1      27.9 ****±**** 5.3 ****±**** 6.1       2.2  ****±  ****1.5** **± ****2.2**
**200     5      12.3      11.5 ****±**** 3.4 ****±**** 2.5       0.82 ****± ****0.91** **±** **0.86****250     3        5.7        5.3 ****±**** 2.3 ****±**** 1.2       0.36 ****± ****0.60 ****± ****0.38****300     3        2.8        2.6 ****±**** 1.6 ****±**** 0.6       0.17 ****± ****0.41** **±**** 0.18****350     1        1.4        1.3 ****±**** 1.1 ****±**** 0.3       0.08** **± ****0.28** **± ****0.08****400     1        0.65      0.61 ****±**** 0.78 ****± ****0.14 0.04 ****± ****0.19** **±**** 0.04**
**450     0        0.30      0.29 ****±**** 0.54 ****±**** 0.07 0.017 ****± ****0.129** **±**** 0.017**

- Diphox Systematic uncertainty from: renormalisation scale 20%,
- luminosity 6%, scaling factor for eta correction: 0.8%,
- variation in efficiency fit to Pythia (3%-10%) Fakes Systematic uncertainty from sideband variations

-  GeV/c2

- Integral Plot

- CDF Run II Preliminary (345pb-1)

## Limit Plot

- Same procedures as blessed
- Bayesian Stats
- BG subtraction

##  Limit Table

## Exclusion Plot

- Same procedures as blessed

##  Combined Exclusion Plot

- Same procedure as blessed

## Cos* plots

**Cos***** plots**

- 5 highest mass events
- _Mass __	__Cos____* (Collins-Soper)_
- 206.6 	-0.470247.9   	-0.088304.8 	-0.329328.5	-0.082404.9   	 0.517

## Additional Plots

## Limit Changes with PDF 

## Fake Rate

- Sample       Fake Rate (%)	    	Z pred
- 	0		1.6 ± 0.4		0.5 ± 0.2
- 	1		1.9 ± 0.3		0.1 ± 0.1
- 	2		2.9 ± 0.9 		0.4 ± 0.3
- 	3		2.8 ± 0.9		0.3 ± 0.2

- Z pred = Z event we expect in our sample
- Expect period 2 to be somewhat higher, but low stats here

*e *fakes  due to conversions or tracking inefficiency

## Collins-Soper Frame

- cos* in Collins-Soper frame

- cos*  =   2  (l+1 l-2 - l+1 l-2)

- M√(M2+PT2)

- M=dilepton pair mass
- PT=dilepton transverse mass
- l±= (l0±l3)/√2
- l1=lepton momentum, l2=anti-lepton momentum
- This formalism minimises correction terms to  introduced from the parton transverse momentum in comparison to those if the production angle were taken as the angle between the photon and the proton beam
- 							CDF 6746* ee*

## Mass Spectra in 4 samples

- 2097

- 458

- 422

- 362

- Sample 0

- Sample 2

- Sample 1

- Sample 3

- 50       100       150        200 GeV/c2

## Searching for         ED

- RS

- (Add BRs here?!)

- (Why not diphoton ?!!)

- K/MPl

- 6

- RS model

- Dilepton channel

-               400  600  800 1000

- 10-2
- 10-4
- 10–6
- 10-8

- Tevatron 700 GeV KK graviton

- d/dM (pb/GeV)

- Massive eigenstates only suppressed by -1 ~ TeV-1
- RS modes can be excited individually on resonance

- Via Virtual exchange
-         but different expected cross sections/distributions from ADD model

- Davoudiasl, Hewett, Rizzo hep-ph0006041

- 1
- 0.7
- 0.5
- 0.3
- 0.2
- 0.1

- The cleanest signature for graviton resonance production is an excess of events in the dilepton or dijet channel.

- K/MPl

- hep-ph 9905221

- Deviations in virtual graviton exchange

- Randall-Sundrum Extra Dimensional Model
- Introduced to address the Hierarchy problem 	(MEW << MPlanck?)
- by having 1 highly curved extra dimension
- Gravity localised in the ED
- Scale of physical phenomena on the TeV-brane is specified by the exponential warp factor:

## Randall-Sundrum Graviton

- Scale of physical phenomena on the TeV-brane is specified by the exponential warp factor:
-            = Mple-kRc
-      ~ TeV if kRc ~11-12.

- Randall-Sundrum gravitons are excluded by these data in the plane of coupling (k/MPl) versus effective graviton mass. E.g. for k/M_Pl=0.05 masses less than 500 GeV are ruled out at 95% C.L..

- for k/M_Pl=0.05 masses less than 500 GeV
- are ruled out at 95% C.L..

- Scale of physical phenomena on the TeV-brane is specified by the exponential warp factor:
-            = Mple-kRc

-  ~ TeV if kRc ~11-12.

- Clean experimental signature. Low backgrounds

- gg initiated process

- Dilepton Channel

- K/Mpl 0.1	620
- 	0.05	470
- 	0.02	310
- 	0.01	200

- Add Run I limits?!

-  **ee** has largest acceptance at low mass
**  ******** **has largest acceptance at high mass
-  BR(**G****→******) =  2 * BR(**G→ee**)

## RS Graviton Limits

**RS Graviton Limits**

- The following plots show the efficiency times acceptance of detecting a particle decaying into a electron-positron pair as function of the mass. Since the spin of the particle changes the angular distribution of the decay particles we consider the possible spin of any new particle separately: spin-0 , spin-1 and spin-2.

**ee**

****

** ****ee** has largest acceptance at low mass
**  ****** has largest acceptance at high mass
-  BR(**G****→******) = 2*BR(G→ee)

****

## Why is acceptance higher for CC  than ee?

-  0211205 hep.ph

- (gg→G→)/(G→)

-  G at high mass are produced via qq, rather than gg
-  qq initiated photons are more centrally distributed than ff
- 	in graviton rest frame (=1)
-  G at high mass are more likely produced near rest  (=1)

- Angular distribution for graviton production and decay (=1)

-  beta represents the velocity of the decay produces, beta = sqrt(1-4m2/MG2) for particles of mass m