Search for Technicolor particles Produced in Association with W boson with 1.9fb^-1 at CDF

Search for Technicolor particles Produced in Association with W boson with 1.9fb^-1 at CDF
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Abstract

Authors

Documentation

Technicolor Signal and Cross Section

Event Selection and Search Strategies

Figures

Signal Acceptance and systematic uncertainties

Background estimation

Reconstructed Mass

95% C.L. Excluded region

Abstract

We present a search for technicolor particles produced in association with W bosons when really technirho decays to a technipion and a W boson with the techniopion decaying to quarks in p-pbar collisions at √s= 1.96 TeV. This search uses data corresponding to an integrated luminosity of 1.9fb-1.
We select double b-tagged W + 2 jets events and one b-tagged W+2jets events. NN flavor separation is applied to one b-tagged events to increase purity of signal events. Three b-tagging categories (double silicon vertex b-tagged events, one silicon vertex b-tagged + Jet Probability b-tagged and one silicon vertex b-tagged w/ NN flavor separator) which have different purity are analized separately.
The observed number of each categories and the invariant mass distributions of W+2 jets and di-jets are consistent with the standard model expectations.
We set a 95% C.L. excluded region as a function of the technicolor particles mass.

Authors:

Yoshikazu Nagai, Shinhong Kim, Tatsuya Masubuchi (University of Tsukuba)
Weiming Yao (LBNL)

Data: Run II, 1.9 fb^-1 --- Collected through May 2007 ---

Docementation

CDF note 9302 ps pdf --- Public note

Technicolor Signal and Cross Section


Feynman diagram	Signal cross section times Branching ratio for neutral/charged &pi_T

Event selection and Search strategies

Search strategies

Double silicon vertex (SECVTX) b-tag events (ST+ST), one SECVTX b-tag + one jet probability (JetProb) b-tag events (ST+JP) and one SECVTX b-tag with NN flavor separator evens are estimated separately due to taking advantage of the S/N ratio in two double tag categories and one single tag category. The best result is given by combined likelihood of two double b-tagging events and one b-tagging events.

Basic event selection

Category	Double SECVTX	One SECVTX + One JetProb	One SECVTX w/ NN
Lepton	Central isolated electron or muon and Plug isolated electron (Pt>20 GeV)
Missing Et	>20 GeV(Central)
Two Jets	>20 GeV, \|&eta\| < 2.0
b-tagging (1st jet)	tight SecVtx b-tag		tight SecVtx b-tag w/ NNtag
b-tagging (2nd jet)	tight SecVtx b-tag	JetProb b-tag	No b-tag

# These three categories are selected exclusively.

Figure

Signal acceptance for neutral &pi_T channels

Acceptance (%)
m(&rho_T,&pi_T)	(180,95)	(190,105)	(200,105)	(200,115)	(210,115)	(210,125)	(220,115)	(220,125)	(220,135)
Double SECVTX	0.32 +/- 0.04	0.36 +/- 0.05	0.37 +/- 0.05	0.40 +/- 0.05	0.38 +/- 0.05	0.41 +/- 0.06	0.38 +/- 0.05	0.43 +/- 0.06	0.43 +/- 0.06
One SECVTX + One JetProb	0.23 +/- 0.04	0.25 +/- 0.04	0.25 +/- 0.04	0.27 +/- 0.04	0.27 +/- 0.04	0.28 +/- 0.05	0.26 +/- 0.04	0.29 +/- 0.05	0.29 +/- 0.05
One SECVTX w/ NN	0.66 +/- 0.04	0.72 +/- 0.06	0.70 +/- 0.06	0.73 +/- 0.06	0.76 +/- 0.07	0.78 +/- 0.07	0.76 +/- 0.07	0.78 +/- 0.07	0.81 +/- 0.07

Acceptance (%)
m(&rho_T,&pi_T)	(230,125)	(230,135)	(230,145)	(240,125)	(240,135)	(240,145)	(240,155)	(250,135)	(250,145)	(250,155)	(250,165)
Double SECVTX	0.41 +/- 0.06	0.43 +/- 0.06	0.45 +/- 0.06	0.40 +/- 0.06	0.43 +/- 0.06	0.46 +/- 0.06	0.45 +/- 0.06	0.42 +/- 0.06	0.45 +/- 0.06	0.46 +/- 0.06	0.45 +/- 0.06
One SECVTX + One JetProb	0.29 +/- 0.05	0.28 +/- 0.05	0.29 +/- 0.05	0.28 +/- 0.05	0.32 +/- 0.05	0.29 +/- 0.05	0.29 +/- 0.05	0.29 +/- 0.05	0.31 +/- 0.05	0.30 +/- 0.05	0.31 +/- 0.05
One SECVTX w/ NN	0.80 +/- 0.07	0.82 +/- 0.07	0.82 +/- 0.07	0.82 +/- 0.07	0.81 +/- 0.07	0.84 +/- 0.07	0.80 +/- 0.07	0.85 +/- 0.07	0.84 +/- 0.07	0.83 +/- 0.07	0.81 +/- 0.07

Signal acceptance for charged &pi_T channels

Acceptance (%)
m(&rho_T,&pi_T)	(180,95)	(190,105)	(200,105)	(200,115)	(210,115)	(210,125)	(220,115)	(220,125)	(220,135)
Double SECVTX	0.04 +/- 0.01	0.05 +/- 0.01	0.05 +/- 0.01	0.05 +/- 0.01	0.05 +/- 0.01	0.05 +/- 0.01	0.05 +/- 0.01	0.05 +/- 0.01	0.07 +/- 0.01
One SECVTX + One JetProb	0.09 +/- 0.01	0.09 +/- 0.02	0.09 +/- 0.02	0.10 +/- 0.02	0.11 +/- 0.02	0.11 +/- 0.02	0.10 +/- 0.02	0.11 +/- 0.02	0.12 +/- 0.02
One SECVTX w/ NN	0.69 +/- 0.06	0.75 +/- 0.06	0.73 +/- 0.06	0.81 +/- 0.07	0.78 +/- 0.07	0.80 +/- 0.07	0.77 +/- 0.07	0.83 +/- 0.07	0.83 +/- 0.07

Acceptance (%)
m(&rho_T,&pi_T)	(230,125)	(230,135)	(230,145)	(240,125)	(240,135)	(240,145)	(240,155)	(250,135)	(250,145)	(250,155)	(250,165)
Double SECVTX	0.06 +/- 0.01	0.06 +/- 0.01	0.06 +/- 0.01	0.06 +/- 0.01	0.06 +/- 0.01	0.07 +/- 0.01	0.06 +/- 0.01	0.06 +/- 0.01	0.07 +/- 0.01	0.06 +/- 0.01	0.06 +/- 0.01
One SECVTX + One JetProb	0.11 +/- 0.02	0.12 +/- 0.02	0.13 +/- 0.02	0.11 +/- 0.02	0.12 +/- 0.02	0.12 +/- 0.02	0.12 +/- 0.02	0.11 +/- 0.02	0.12 +/- 0.02	0.13 +/- 0.02	0.13 +/- 0.02
One SECVTX w/ NN	0.82 +/- 0.07	0.83 +/- 0.07	0.83 +/- 0.07	0.82 +/- 0.07	0.83 +/- 0.07	0.85 +/- 0.07	0.83 +/- 0.07	0.84 +/- 0.07	0.85 +/- 0.07	0.84 +/- 0.07	0.83 +/- 0.07

Systematic uncertainty on the signal acceptance


Systematic uncertainty on the neutral &pi_T acceptance	Systematic uncertainty on the charged &pi_T acceptance

Background Estimation

Background Summary (Double SECVTX b-tag)

Background Summary (One SECVTX b-tag + one JetProb b-tag)

Background Summary (One SECVTX b-tag w/ NN flavor separator)

Reconstructed Mass

@ Di-jet and W+2jets invariant mass

Dijet mass(left) and W+2jets mass(right) for double SECVTX b-tag

Dijet mass(left) and W+2jets mass(right) for one SECVTX b-tag + one JetProb b-tag

Dijet mass(left) and W+2jets mass(right) for one SECVTX b-tag w/ NN flavor separator

@ Q value (= m(&rho_T) - m(&pi_T) - m(W) )

Q value for double SECVTX b-tag(left), one SECVTX b-tag + one JetProb b-tag(middle) and one SECVTX tag w/ NN flavor separator(right)

@ 2D plot (Background total)

2-D plots(dijet mass vs Q value) of estimated total background for ST+ST(left), ST+JP(middle) and ST w/ NN flavor separator(right)

@ 2D plot (Data)

2-D plots(dijet mass vs Q value) of observed data for ST+ST(left), ST+JP(middle) and ST w/ NN flavor separator(right)

@ 2D plot (signal m(&rho_T)=200GeV, m(&pi_T)=115GeV)

2-D plots(dijet mass vs Q value) of expected Technicolor signal for ST+ST(left), ST+JP(middle) and ST w/ NN flavor separator(right)

95% C.L. excluded region

@ We combine three tag categories to obtain the best limit and set the 95% C.L. excluded region as a function of the technicolor particles mass. Next plots show the expected/observed 95% C.L. excleded region as a function of m(&rho_T) and m(&pi_T).