First observation of the eta_b meson and study of the decays Upsilon(3S) -> gamma eta_b and Upsilon(2S) -> gamma eta_b
Abstract/Contents
- Abstract
- This dissertation presents the results of an analysis of data samples consisting of 122 million Upsilon(3S) decays and 90 million Upsilon(2S) decays collected with the BABAR detector operating at the PEP II asymmetric-energy storage rings at SLAC National Accelerator Laboratory. The eta_b meson is observed for the first time in the decay Upsilon(3S) -> gamma eta_b and its existence is confirmed in the decay Upsilon(2S) -> gamma eta_b. The eta_b mass extracted from the Upsilon(3S) -> gamma eta_b sample is 9388.9^{+3.1}_{-2.3}(stat) +/- 2.7 (syst) MeV/c^2, corresponding to a hyperfine mass splitting m_{Upsilon(1S)}-m_{eta_b}=71.4^{+2.3}_{-3.1}(stat) +/- 2.7(syst) MeV/c^2. The branching fraction for the decay Upsilon(3S) -> gamma eta_b is determined to be [4.8 +/- 0.5(stat) +/- 0.6(syst)] x 10^{-4}. An analysis of the decay Upsilon(2S) -> gamma eta_b confirms the observation of the eta_b meson and provides an additional measurement of the eta_b mass: 9394.2^{+4.8}_{-4.9}(stat) +/- 2.0 (syst) MeV/c^2. The branching fraction for the decay Upsilon(2S) -> gamma eta_b is determined to be [3.9 +/- 1.1(stat)^{+1.1}_{-0.9} (syst)] x 10^{-4}. As the measurements in the two samples are consistent, the masses are averaged to provide a combined value of m_{eta_b} = 9390.9 +/- 3.2 MeV/c^2. After canceling common systematic errors, the following branching fraction ratio is determined: BR[Upsilon(2S) -> gamma eta_b]/BR[Upsilon(3S) -> gamma eta_b] = 0.82 +/- 0.24(stat)^{+0.20}_{-0.19}(syst).
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2010 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | West, Christopher Alan |
|---|---|
| Associated with | Stanford University, Department of Physics |
| Primary advisor | Schindler, Rafe |
| Thesis advisor | Schindler, Rafe |
| Thesis advisor | Burchat, P. (Patricia) |
| Thesis advisor | Dorfan, Jonathan |
| Thesis advisor | Peskin, Michael Edward, 1951- |
| Advisor | Burchat, P. (Patricia) |
| Advisor | Dorfan, Jonathan |
| Advisor | Peskin, Michael Edward, 1951- |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Christopher West. |
|---|---|
| Note | Submitted to the Department of Physics. |
| Thesis | Thesis (Ph. D.)--Stanford University, 2010. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2010 by Christopher Alan West
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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