Search for the Decay $\tau^- \rightarrow 3\pi^- 2\pi^+2\pi^0 \nu_\tau$

Aubert, B.

Stanford Linear Accelerator Center

关键词: Decay;    Resonance Experiment-Hep,Hepex;    Experiment-Hep,Hepex;    Pions;    72 Physics Of Elementary Particles And Fields;   

DOI  :  10.2172/881120
RP-ID  :  SLAC-PUB-11804
RP-ID  :  AC02-76SF00515
RP-ID  :  881120

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来源: UNT Digital Library

【 摘 要 】

A search for the decay of the {tau} lepton to five charged and two neutral pions is performed using data collected by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider. The analysis uses 232 fb{sup -1} of data at center-of-mass energies on or near the {Upsilon}(4S) resonance. We observe 10 events with an expected background of 6.5{sub -1.4}{sup +2.0} events. In the absence of a signal, we set the limit on the branching ratio {Beta}({tau}{sup -} {yields} 3{pi}{sup -}2{pi}{sup +}2{pi}{sup 0}{nu}{sub {tau}}) < 3.4 x 10{sup -6} at the 90% confidence level. This is a significant improvement over the previously established limit. In addition, we search for the decay mode {tau}{sup -} {yields} 2{omega}{pi}{sup -}{nu}{sub {tau}}. We observe 1 event with an expected background of 0.4{sub -0.4}{sup +1.0} events and calculate the upper limit {Beta}({tau}{sup -} {yields} 2{omega}{pi}{sup -}{nu}{sub {tau}}) < 5.4 x 10{sup -7} at the 90% confidence level. This is the first upper limit for this mode.