Measurement of Tau Branching Ratios.
Abstract
Several branching ratios for (tau) decays have been measured using e('+)e(') (>) (tau)('+)(tau)(' ) events. The data were accumulated with the TPC/TwoGamma detector at the SLAC e('+)e(') storage ring PEP and corresponded to an integrated luminosity of 77 pb('1) at a centerof mass energy of 29 GeV. One data sample consisted of events which had final state topologies containing onecharged particle opposite to threechargedparticle, while the second data sample consisted of events in which both (tau)'s decayed to only one charged particle each. The one and threechargedparticle inclusive branching ratios of the (tau) decay were measured to be (84.6 (+OR) 0.9(,1.0)('+0.9))% and 15.4 (+OR) 0.9(, 0.9)('+1.0))%. The branching ratios of the two leptonic decays and two semihadronic decays of the (tau), B((tau) (>) e(nu)(,e)(nu)(,(tau))), B((tau) (>) (mu)(nu)(,(mu))(nu)(,(tau))), B((tau) (>) one charged hadron + neutrals), and B((tau) (>) (pi)(') + neutrals), were measured to be (19.4 (+OR) 1.3(,1.6)('+1.8))%, (18.2 (+OR) 1.2(,0.4)('+0.5))%, (47.0 (+OR) 1.2(,0.9)('+0.4))%, and (45.5 (+OR) 1.2(, 0.9)('0.5))%, respectively. Using particle identification by dE/dx in the TPC, charged K mesons in oneprong (tau) decays were identified. With the identified K mesons the branching ratios of Cabibbosuppressed (tau) decays, B((tau)('  )(>) K(')(nu)(,(tau)) + N(,(gamma))) with N (GREATERTHEQ) 0 and N (GREATERTHEQ) 1, were measured to be (1.5 (+OR ) 0.3 (+OR) 0.2)% and (1.1 (+OR) 0.4 (+OR) 0.2)%. A search was also made for K*('(+OR))(892)'s by reconstructing the decay, K*('(+OR) )(>) K(,8)('0)(pi)('(+OR)), with the three (pi)'s in threeprong (tau) decays. The branching ratio of the Cabibbosuppressed (tau) decay, B((tau)('  )(>) K*(')(892)(nu)(,(tau))), was measured to be (1.4 (+OR) 0.9)%. In addition to these branching ratios, an upper limit on the branching ratio of the rare (tau) decay, B((tau)('(+OR) )(>) K('(+OR)) + 2 charged + neutrals), of 0.6% (90% C.L.) was set for the first time. The quoted errors are the combined statistical and systematic errors.
 Publication:

Ph.D. Thesis
 Pub Date:
 1986
 Bibcode:
 1986PhDT........25Z
 Keywords:

 Physics: Elementary Particles and High Energy