English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Zendy Plus

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Zendy Tools

Zendy Open

One of the most remarkable properties of the top quark is its e x remely short lifetime, which allows us to observe the top quark spin at its productio n. That means a spin correlation attt̄ production is possible to be observed. In this thesis, we rep ort on a measurement of the correlation coefficient between top quark sp in and antitop quark spin in the beam basis at top quark pair production. We select tt̄ pair production candidates by requiring two high transverse momentum leptons, two jets an d l rge missingET . In order to reconstruct the angular distribution of top quark decay p roducts, we perform full kinematical reconstruction using predicted distributions of p z , p tt̄ T andMtt̄. We make signal and background templates from admixture of Monte Carlo simul ations and data-based background modelings. Then, we perform unbinned likelihoo d fit of angular distribution of data to signal and background templates and obtain result . This analysis is based on the data of5.1 fb collected with the Collider Detector Facility (CDF) at the Fer milab Tevatron between March 2002 and June 2009. We observe 334 tt̄ candidate events. We determine a confidence interval at 68 % level for the correlation coefficient κ to be −0.520 < κ < 0.605 or κ = 0.042 −0.562 on the assumption of Mtop = 172.5 GeV/ c. Acknowledgments I would like to thank people who have helped me and contribute to my growth in my college life. First of all, I would like to acknowledge a great debt to my adv isor, Prof. Shinhong Kim and Prof. Yuji Takeuchi for giving me the opportunity to w ork on CDF and suggesting the topic of this analysis. They have gave me a lot of a divices and always guided me in the right direction. Without their support and encoura gement, this thesis would not have been possible. I wish to thank staff of the High Energy Physics group of Unive rsity of Tsukuba, Prof. Fumihiko Ukegawa, Prof. Kazuhiko Hara, Prof. Koji Sat o, Dr. Hideki Miyake, Dr. Masakazu Kurata, Dr. Koichi Nagai for their kindness. They g ive me a lot of suggestions to my analysis. I also thank students who belong to the High En ergy Physics group of University of Tsukuba. I shared good times with them. In part icular, I would like to thank Yuji Sudo who is my peer. He listened to my problem on analysis and supported my life at Fermilab. Also, I would like to thank academic collea gue at Fermilab, Atsunari Hamaguchi, Daisuke Yamato, Yuki Sakurai, Yujiro Funakoshi , and people who belonged the High Energy Physics group of University of Tsukuba, Prof . Takasumi Maruyama, Dr. Naoki Kimura, Dr. Tomonobu Tomura, Dr. Junji Naganoma, M asato Aoki and Dr. Yoshikazu Nagai. They gave me a lot of advices and provided mo tivation to analysis. I wish to express apprecisation to Kazuko Kumashiro, Kyoko K unori for their constant support with their secretarial works. Conveners of CDF Top Group and Dilepton working group gave me a l ot of helps. My deep thank go to the members of CDF top dilepton working group, Jaroslav Antos, Yen Chu Chen, Hyunsoo Kim, Chang-Seong Moon, Youngdo Oh, Andy Beret vas, Soo-Bong Kim, Roman Lysak and Satoru Uozumi. I thank the Fermilab staf f and the technical staffs of the participating insttutions for their vital contribut ions. I wish to thank my best friend Junichi Tanaka. Playing with hi m was a nice change of pace for me. Finally, I would like to thank my parents and my sister.

Measurement of the Spin Correlation in the Top Quark Pair Production using the Dilepton Events in 1.96-TeV Proton-Antiproton Collisions