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Search for second generation leptoquarks with ATLAS at the LHC

Abstract

The Large Hadron Collider will collide protons with protons at a center-of-mass energy of up to 14 TeV. New physics phenomena and new particles are predicted to be detectable with the ATLAS detector at the Large Hadron Collider. One of these predicted new particles beyond the Standard Model are leptoquarks. This thesis deals with the search for scalar second generation leptoquarks produced in pairs. Second generation leptoquarks decay into a muon-type lepton and a quark. In this thesis the decay of both second generation leptoquarks into a muon and a quark is considered. Since pair production is studied the final state consists of two high-energetic muons and two high-energetic jets. This thesis studies second generation leptoquarks with masses of m{sub LQ}=300 GeV, m{sub LQ}=400 GeV, m{sub LQ}=600 GeV and m{sub LQ}=800 GeV. The best cut variables for the discrimination between the signal and the main Standard Model backgrounds t anti t and Z/{gamma}{sup *} found in this analysis are the p{sub T} of the muons, S{sub T} (the scalar sum of the transverse momenta of the two selected muons and the transverse energies of the two selected jets), the mass of the selected dimuon system and the reconstructed leptoquark mass.  More>>
Authors:
Publication Date:
Jul 18, 2008
Product Type:
Thesis/Dissertation
Report Number:
INIS-DE-0622
Resource Relation:
Other Information: TH: Diss.
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; REST MASS; PAIR PRODUCTION; TRANSVERSE MOMENTUM; TRANSVERSE ENERGY; PROTON-PROTON INTERACTIONS; TEV RANGE 10-100; SEMILEPTONIC DECAY; MULTIPLE PRODUCTION; JET MODEL; HADRONS; MUONS PLUS; MUONS MINUS; EFFECTIVE MASS; BEAM LUMINOSITY; COLLIDING BEAMS; PROTON BEAMS; CERN LHC; INTERMEDIATE BOSONS; GRAND UNIFIED THEORY; COUNTING TECHNIQUES
OSTI ID:
21157837
Research Organizations:
Muenchen Univ. (Germany). Fakultaet fuer Physik
Country of Origin:
Germany
Language:
English
Other Identifying Numbers:
TRN: DE09F3975
Availability:
Commercial reproduction prohibited; INIS; OSTI as DE21157837
Submitting Site:
DEN
Size:
110 pages
Announcement Date:
May 16, 2009

Citation Formats

Krobath, Gernot. Search for second generation leptoquarks with ATLAS at the LHC. Germany: N. p., 2008. Web.
Krobath, Gernot. Search for second generation leptoquarks with ATLAS at the LHC. Germany.
Krobath, Gernot. 2008. "Search for second generation leptoquarks with ATLAS at the LHC." Germany.
@misc{etde_21157837,
title = {Search for second generation leptoquarks with ATLAS at the LHC}
author = {Krobath, Gernot}
abstractNote = {The Large Hadron Collider will collide protons with protons at a center-of-mass energy of up to 14 TeV. New physics phenomena and new particles are predicted to be detectable with the ATLAS detector at the Large Hadron Collider. One of these predicted new particles beyond the Standard Model are leptoquarks. This thesis deals with the search for scalar second generation leptoquarks produced in pairs. Second generation leptoquarks decay into a muon-type lepton and a quark. In this thesis the decay of both second generation leptoquarks into a muon and a quark is considered. Since pair production is studied the final state consists of two high-energetic muons and two high-energetic jets. This thesis studies second generation leptoquarks with masses of m{sub LQ}=300 GeV, m{sub LQ}=400 GeV, m{sub LQ}=600 GeV and m{sub LQ}=800 GeV. The best cut variables for the discrimination between the signal and the main Standard Model backgrounds t anti t and Z/{gamma}{sup *} found in this analysis are the p{sub T} of the muons, S{sub T} (the scalar sum of the transverse momenta of the two selected muons and the transverse energies of the two selected jets), the mass of the selected dimuon system and the reconstructed leptoquark mass. The latter three cut variables have been optimized for a discovery with a 5{sigma} significance including the systematic uncertainties and trigger efficiencies. Second generation leptoquarks have been excluded up to the mass of 300 GeV with a 95% confidence level at present experiments. The expected integrated luminosities needed for a 5{sigma} discovery of the tested second generation leptoquark masses with the ATLAS detector have been calculated. This thesis shows that for a discovery with 5{sigma} significance of a second generation leptoquark with m{sub LQ}=300 GeV and m{sub LQ}=400 GeV an expected integrated luminosity of 1.51 pb{sup -1} and 7.42 pb{sup -1} is needed respectively; this corresponds to a very early phase, i.e. the first few months, of the Large Hadron Collider run. For the discovery with a 5{sigma} significance of second generation leptoquarks with masses of m{sub LQ} = 600 GeV and m{sub LQ} = 800 GeV an expected integrated luminosity of 103.3 pb{sup -1} and 663 pb{sup -1} is needed respectively; this corresponds to several months and about half a year to a year of the Large Hadron Collider run respectively. (orig.)}
place = {Germany}
year = {2008}
month = {Jul}
}