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Title: Search for gluino and squark production in multi-jets plus missing transverse energy final states at the Tevatron using the CDF detector

Abstract

In this thesis, the results of the search for squarks and gluinos in multiple jets plus missing transverse energy final states have been presented. No evidence of these new particles have been found in 371 pb -1 of CDF Run II data. New limits have been set which exclude gluino masses below 220 GeV and, in the region where M $$\tilde{g}$$ ~ M $$\tilde{q}$$, masses below 380 GeV/c 2 are excluded. These limits are valid in a mSUGRA scenario with tan β = 5, A = 0 and μ < 0 assuming the lightest four squark flavours degenerate in mass. To obtain these results a careful study of the beam conditions and their contribution to events with E T final states has been performed. Special attention has been taken in studying the different SM backgrounds and their normalizations at NLO. Dedicated cuts have been introduced to remove the background processes and main discriminating variables have been optimized for different signal regions. The different systematic uncertainties have also been considered. This is the first time that this search is performed at CDF Run II and the results presented here show significant improvements with respect to the constraints from previous experiments. Thus, this analysis has established the procedure to continue searching for squarks and gluinos with the new data samples that CDF is collecting from Tevatron. Some improvements may also be implemented by considering other hadron final states with different jet multiplicities. This could help extending the sensitivity of the analysis to regions where gluino and squark masses are not similar. At the forthcoming LHC, the search for squarks and gluinos in this inclusive channel constitutes one of the first analyses to be performed. The E T and multiple jets final states are present in multiple decay modes of many models beyond the SM. The experience from Tevatron in working on an hadron collider environment will be useful for these kind of studies aiming to discover the presence of supersymmetric processes.

Authors:
 [1]
  1. Autonomous Univ. of Barcelona, Bellaterra (Spain). Inst. for High Energy Physics
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
902543
Report Number(s):
FERMILAB-THESIS-2007-02
TRN: US0702944
DOE Contract Number:  
AC02-07CH11359
Resource Type:
Thesis/Dissertation
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; DECAY; FERMILAB COLLIDER DETECTOR; FERMILAB TEVATRON; HADRONS; PRODUCTION; SENSITIVITY; TRANSVERSE ENERGY; Experiment-HEP

Citation Formats

Portell i Bueso, Xavier. Search for gluino and squark production in multi-jets plus missing transverse energy final states at the Tevatron using the CDF detector. United States: N. p., 2007. Web. doi:10.2172/902543.
Portell i Bueso, Xavier. Search for gluino and squark production in multi-jets plus missing transverse energy final states at the Tevatron using the CDF detector. United States. doi:10.2172/902543.
Portell i Bueso, Xavier. Mon . "Search for gluino and squark production in multi-jets plus missing transverse energy final states at the Tevatron using the CDF detector". United States. doi:10.2172/902543. https://www.osti.gov/servlets/purl/902543.
@article{osti_902543,
title = {Search for gluino and squark production in multi-jets plus missing transverse energy final states at the Tevatron using the CDF detector},
author = {Portell i Bueso, Xavier},
abstractNote = {In this thesis, the results of the search for squarks and gluinos in multiple jets plus missing transverse energy final states have been presented. No evidence of these new particles have been found in 371 pb-1 of CDF Run II data. New limits have been set which exclude gluino masses below 220 GeV and, in the region where M$\tilde{g}$ ~ M$\tilde{q}$, masses below 380 GeV/c2 are excluded. These limits are valid in a mSUGRA scenario with tan β = 5, A = 0 and μ < 0 assuming the lightest four squark flavours degenerate in mass. To obtain these results a careful study of the beam conditions and their contribution to events with ET final states has been performed. Special attention has been taken in studying the different SM backgrounds and their normalizations at NLO. Dedicated cuts have been introduced to remove the background processes and main discriminating variables have been optimized for different signal regions. The different systematic uncertainties have also been considered. This is the first time that this search is performed at CDF Run II and the results presented here show significant improvements with respect to the constraints from previous experiments. Thus, this analysis has established the procedure to continue searching for squarks and gluinos with the new data samples that CDF is collecting from Tevatron. Some improvements may also be implemented by considering other hadron final states with different jet multiplicities. This could help extending the sensitivity of the analysis to regions where gluino and squark masses are not similar. At the forthcoming LHC, the search for squarks and gluinos in this inclusive channel constitutes one of the first analyses to be performed. The ET and multiple jets final states are present in multiple decay modes of many models beyond the SM. The experience from Tevatron in working on an hadron collider environment will be useful for these kind of studies aiming to discover the presence of supersymmetric processes.},
doi = {10.2172/902543},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}

Thesis/Dissertation:
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