A Search for the Rare Leptonic B- to tau- anti-neutrino Recoiling against B+ to Decays to anti-D*0 l+ Lepton-neutrino
This thesis describes a search for the decay B{sup -} {yields} {tau}{sup -}{bar {nu}}{sub {tau}} in 231.8 x 10{sup 6} {Upsilon}(4S) decays recorded with the BABAR detector at the SLAC PEP-II B-Factory. A sample of events with one reconstructed exclusive semi-leptonic B decay (B{sup +} {yields} {bar D}*{sup 0} {ell}{sup +}{nu}{sub {ell}}) is selected, and in the recoil a search for B{sup -} {yields} {tau}{sup -} {bar {nu}}{sub {tau}} signal is performed in the following {tau} decay modes: {tau}{sup -} {yields} e{sup -}{bar {nu}}{sub e}{nu}{sub {tau}}, {tau}{sup -} {yields} {mu}{sup -}{bar {nu}}{sub {mu}}{nu}{sub {tau}}, {tau}{sup -} {yields} {pi}{sup -}{nu}{sub {tau}}, {tau}{sup -} {yields} {pi}{sup -}{pi}{sup 0}{nu}{sub {tau}}, and {tau}{sup -} {yields} {pi}{sup -}{pi}{sup +}{pi}{sup -}{nu}{sub {tau}}. They find no evidence of signal, and they set a preliminary upper limit on the branching fraction of {beta}(B{sup -} {yields} {tau}{sup -}{bar {nu}}{sub {tau}}) < 2.8 x 10{sup -4} at the 90% confidence level (CL). This result is then combined with a statistically independent BABAR search for B{sup -} {yields} {tau}{sup -}{bar {nu}}{sub {tau}} to give a combined preliminary limit of {Beta}(B{sup -} {yields} {tau}{sup -}{bar {nu}}{sub {tau}}) < 2.6 x 10{sup -4} at 90% CL.
- Research Organization:
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC02-76SF00515
- OSTI ID:
- 893772
- Report Number(s):
- SLAC-R-597; TRN: US0805439
- Country of Publication:
- United States
- Language:
- English
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