{"id":{"repo_id":"heid-diss","oai_identifier":"oai:archiv.ub.uni-heidelberg.de:7240"},"canonical_url":"https://search.dev.ndltd.org/etd/heid-diss/oai:archiv.ub.uni-heidelberg.de:7240","repository":{"repo_id":"heid-diss","name":"Universität Heidelberg","base_url":"http://archiv.ub.uni-heidelberg.de/volltextserver/cgi/oai2"},"display":{"title":"Analysis of Events with Isolated Leptons and Missing Transverse Momentum in ep Collisions at HERA","abstract":"A study of events with isolated leptons and missing transverse momentum in ep collisions is presented. Within the Standard Model (SM) such topologies are expected mainly from production of real W bosons with subsequent leptonic decay. This thesis continues the analysis of such events done in the HERA-1 period where an excess over the SM prediction was observed for events with high hadronic transverse momentum PTX > 25 GeV. New data of the HERA-2 period are added. The analysed data sample recorded in e+p collisions corresponds to an integrated luminosity of 220 pb-1 which is a factor of two more with respect to the HERA-1 analysis. The e-p data correspond to 186 pb-1 which is a factor of 13 more with respect to HERA-1. All three lepton generations (electrons muons and tau leptons) are analysed. In the electron and muon channels a total of 53 events are observed in 406 pb-1. This compares well to the SM expectation of 53.7 +- 6.5 events, dominated by W production. However a difference in the event rate is observed for different electron beam charges. In e+p data the excess of events with PTX > 25 GeV is sustained, while the e-p data agree with the SM. In the tau channel 18 events are observed in all HERA data, with 20+-3 expected from the SM. The events are dominated by irreducible background from charged currents. The contribution from W production amounts to about 22%. One event with PTX > 25 GeV is observed, where 1.4 +- 0.3 are expected from the SM.","abstract_html":"A study of events with isolated leptons and missing transverse momentum in ep collisions is presented. Within the Standard Model (SM) such topologies are expected mainly from production of real W bosons with subsequent leptonic decay. This thesis continues the analysis of such events done in the HERA-1 period where an excess over the SM prediction was observed for events with high hadronic transverse momentum PTX > 25 GeV. New data of the HERA-2 period are added. The analysed data sample recorded in e+p collisions corresponds to an integrated luminosity of 220 pb-1 which is a factor of two more with respect to the HERA-1 analysis. The e-p data correspond to 186 pb-1 which is a factor of 13 more with respect to HERA-1. All three lepton generations (electrons muons and tau leptons) are analysed. In the electron and muon channels a total of 53 events are observed in 406 pb-1. This compares well to the SM expectation of 53.7 +- 6.5 events, dominated by W production. However a difference in the event rate is observed for different electron beam charges. In e+p data the excess of events with PTX > 25 GeV is sustained, while the e-p data agree with the SM. In the tau channel 18 events are observed in all HERA data, with 20+-3 expected from the SM. The events are dominated by irreducible background from charged currents. The contribution from W production amounts to about 22%. One event with PTX > 25 GeV is observed, where 1.4 +- 0.3 are expected from the SM.","abstract_has_math":false,"creators":["Brandt, Gerhard Immanuel"],"institution":"Universität Heidelberg","degree_name":null,"degree_level":"thesis.doctoral","degree_discipline":null,"degree_department":null,"school":null,"contributors":["Eisele, Franz"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2007,"date_issued":"2007-02-07","date_published":"2007-02-07","updated_at":"2026-07-24T02:30:41Z","subjects":[],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://www.ub.uni-heidelberg.de/archiv/7240","outbound_label":"Repository record","outbound_source":"source_url"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Eisele, Franz"]},{"key":"dc:creator","label":"Author","values":["Brandt, Gerhard Immanuel"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:publisher","label":"Institution","values":["Universitätsbibliothek Heidelberg"]},{"key":"dc:type","label":"Dc Type","values":["doctoralThesis"]},{"key":"thesis:degree_level","label":"Degree Level","values":["thesis.doctoral"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Universität Heidelberg"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["A study of events with isolated leptons and missing transverse momentum in ep collisions is presented. Within the Standard Model (SM) such topologies are expected mainly from production of real W bosons with subsequent leptonic decay. This thesis continues the analysis of such events done in the HERA-1 period where an excess over the SM prediction was observed for events with high hadronic transverse momentum PTX > 25 GeV. New data of the HERA-2 period are added. The analysed data sample recorded in e+p collisions corresponds to an integrated luminosity of 220 pb-1 which is a factor of two more with respect to the HERA-1 analysis. The e-p data correspond to 186 pb-1 which is a factor of 13 more with respect to HERA-1. All three lepton generations (electrons muons and tau leptons) are analysed. In the electron and muon channels a total of 53 events are observed in 406 pb-1. This compares well to the SM expectation of 53.7 +- 6.5 events, dominated by W production. However a difference in the event rate is observed for different electron beam charges. In e+p data the excess of events with PTX > 25 GeV is sustained, while the e-p data agree with the SM. In the tau channel 18 events are observed in all HERA data, with 20+-3 expected from the SM. The events are dominated by irreducible background from charged currents. The contribution from W production amounts to about 22%. One event with PTX > 25 GeV is observed, where 1.4 +- 0.3 are expected from the SM.","Eine Studie von Ereignissen mit isolierten Leptonen und fehlendem Transversal-Impuls in ep Kollisionen wird vorgestellt. Im Standardmodell (SM) werden Ereignisse mit dieser Topologie vorwiegend durch Produktion reeller W Bosonen mit anschliessendem leptonischen Zerfall erwartet. In der vorliegenden Arbeit wird die Suche solcher Ereignisse im HERA-1 Datensatz fortgefu\"hrt, wo gegenu\"ber der Erwartung im SM ein U\"berschuss an Ereignissen mit hohem hadronischen Transversal-Impuls PTX > 25 GeV gefunden wurde. Dieser Analyse werden neue Daten aus der HERA-2 Datennahmeperiode hinzugefu\"gt. Der analysierte Datensatz von aufgezeichneten e+p Kollisionen entspicht damit einer integrierten Luminosita\"t von 220 pb-1, was etwa doppelt so viel ist wie in HERA-1. Der e-p Datensatz entspricht 186 pb-1, was etwa dreizehnmal so viel ist wie in HERA-1. Es wurden alle drei Lepton-Generationen (Elektronen, Myonen und Tau-Leptonen) analysiert. Im Elektron- und Myon-Kanal werden insgesamt 53 Ereignisse in 406 pb-1 beobachtet. Dies stimmt gut mit der Erwartung von 53.7 +- 6.5 Ereignissen im SM u\"berein, die durch die Produktion reeller W Bosonen dominiert ist. Bei unterschiedlicher Ladung des ElektronStrahls werden jedoch unterschiedliche Ereignisraten beobachtet. Wa\"hrend im e+p Datensatz der U\"berschuss von Ereignissen mit PTX > 25 GeV nach wie vor besteht, stimmt der e-p Datensatz mit der Erwartung im SM u\"berein. Im Tau-Kanal werden im gesamten HERA Datensatz 18 Ereignisse bei einer Erwartung von 20+-3 Ereignissen im SM beobachtet. Sie werden durch irreduziblen Untergrund aus geladenen Stro\"men dominiert. Der Anteil an reeller W Produktion betra\"gt dabei etwa 22%. Es wurde ein Ereignis mit PTX > 25 GeV bei einer Erwartung von 1.4 +- 0.3 Ereignissen im SM beobachtet."]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Analysis of Events with Isolated Leptons and Missing Transverse Momentum in ep Collisions at HERA","Untersuchung von Ereignissen mit isolierten Leptonen und fehlendem Transversalimpuls in ep Kollisionen bei HERA"]}]}],"canonical_facts":{"dc:contributor":["Eisele, Franz"],"dc:creator":["Brandt, Gerhard Immanuel"],"dc:description.abstract":["A study of events with isolated leptons and missing transverse momentum in ep collisions is presented. Within the Standard Model (SM) such topologies are expected mainly from production of real W bosons with subsequent leptonic decay. This thesis continues the analysis of such events done in the HERA-1 period where an excess over the SM prediction was observed for events with high hadronic transverse momentum PTX > 25 GeV. New data of the HERA-2 period are added. The analysed data sample recorded in e+p collisions corresponds to an integrated luminosity of 220 pb-1 which is a factor of two more with respect to the HERA-1 analysis. The e-p data correspond to 186 pb-1 which is a factor of 13 more with respect to HERA-1. All three lepton generations (electrons muons and tau leptons) are analysed. In the electron and muon channels a total of 53 events are observed in 406 pb-1. This compares well to the SM expectation of 53.7 +- 6.5 events, dominated by W production. However a difference in the event rate is observed for different electron beam charges. In e+p data the excess of events with PTX > 25 GeV is sustained, while the e-p data agree with the SM. In the tau channel 18 events are observed in all HERA data, with 20+-3 expected from the SM. The events are dominated by irreducible background from charged currents. The contribution from W production amounts to about 22%. One event with PTX > 25 GeV is observed, where 1.4 +- 0.3 are expected from the SM.","Eine Studie von Ereignissen mit isolierten Leptonen und fehlendem Transversal-Impuls in ep Kollisionen wird vorgestellt. Im Standardmodell (SM) werden Ereignisse mit dieser Topologie vorwiegend durch Produktion reeller W Bosonen mit anschliessendem leptonischen Zerfall erwartet. In der vorliegenden Arbeit wird die Suche solcher Ereignisse im HERA-1 Datensatz fortgefu\"hrt, wo gegenu\"ber der Erwartung im SM ein U\"berschuss an Ereignissen mit hohem hadronischen Transversal-Impuls PTX > 25 GeV gefunden wurde. Dieser Analyse werden neue Daten aus der HERA-2 Datennahmeperiode hinzugefu\"gt. Der analysierte Datensatz von aufgezeichneten e+p Kollisionen entspicht damit einer integrierten Luminosita\"t von 220 pb-1, was etwa doppelt so viel ist wie in HERA-1. Der e-p Datensatz entspricht 186 pb-1, was etwa dreizehnmal so viel ist wie in HERA-1. Es wurden alle drei Lepton-Generationen (Elektronen, Myonen und Tau-Leptonen) analysiert. Im Elektron- und Myon-Kanal werden insgesamt 53 Ereignisse in 406 pb-1 beobachtet. Dies stimmt gut mit der Erwartung von 53.7 +- 6.5 Ereignissen im SM u\"berein, die durch die Produktion reeller W Bosonen dominiert ist. Bei unterschiedlicher Ladung des ElektronStrahls werden jedoch unterschiedliche Ereignisraten beobachtet. Wa\"hrend im e+p Datensatz der U\"berschuss von Ereignissen mit PTX > 25 GeV nach wie vor besteht, stimmt der e-p Datensatz mit der Erwartung im SM u\"berein. Im Tau-Kanal werden im gesamten HERA Datensatz 18 Ereignisse bei einer Erwartung von 20+-3 Ereignissen im SM beobachtet. Sie werden durch irreduziblen Untergrund aus geladenen Stro\"men dominiert. Der Anteil an reeller W Produktion betra\"gt dabei etwa 22%. Es wurde ein Ereignis mit PTX > 25 GeV bei einer Erwartung von 1.4 +- 0.3 Ereignissen im SM beobachtet."],"dc:format.medium":["application/pdf"],"dc:publisher":["Universitätsbibliothek Heidelberg"],"dc:title":["Analysis of Events with Isolated Leptons and Missing Transverse Momentum in ep Collisions at HERA","Untersuchung von Ereignissen mit isolierten Leptonen und fehlendem Transversalimpuls in ep Kollisionen bei HERA"],"dc:type":["doctoralThesis"],"thesis:degree_level":["thesis.doctoral"],"thesis:institution_name":["Universität Heidelberg"]},"updated_at":"2026-07-24T02:30:41Z"}