The branching fraction is measured to be (2.85 +/- 0.56 +/- 0.51) x 10(-4). Measurement of the absolute branching fraction of Ds+ --> tau+ nutau decay Phys Rev Lett. The tau is the only lepton that can decay into hadrons - the other leptons do not have the necessary mass. EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH CERN-PPE/95-140 September 12, 1995 Tau hadronic branching ratios The ALEPH Collaborationu0003 Abstract From 64492 selected u001c -pair events, produced at the Z 0 resonance, the measurement of the tau decays into hadrons from a global analysis using 1991, 1992 and 1993 ALEPH data is presented. 25.49% for decay into a charged pion, a neutral pion, and a tau neutrino;; 10.82% for decay into a charged pion and a tau neutrino; The third column of branching ratios listed in Table 3 are the results of this . Its purpose is to gather the experts on tau lepton physics to examine the current understanding of the tau lepton physics and to assess future prospects. The branching ratio of the common purely leptonic tau decays are: 17.82% for decay into a tau neutrino, electron and electron antineutrino; 17.39% for decay into a tau neutrino, muon and muon antineutrino. This result is combined with other measurements to test e-mu and mu-tau universality in charged . More than 90% of these decays are via eight decay modes (Fig. For the decay of the muon, µ → eν̄e νµ , the same formula applies, with the muon mass and coupling, mµ and gµ , replacing those of the tau. How can I obtain the branching ratios for the tau decay from the CKM ignoring phase space and form factor and please suggest a numerical example if possible? 2008 Apr 25;100(16):161801. doi: 10.1103/PhysRevLett.100.161801. The branching ratio for the decay tau->e nue nutau has been measured using Z0 decay data collected by the OPAL experiment at LEP. In recent years, B-s -> tau(+)tau(-) rare decay has attracted a lot of attention since it is very sensitive to the structure of standard model (SM) and potential source of new physics beyond SM. Recent results on hadronic decays of tau from BaBar are reviewed. [1-4] By definition, the total branching fraction for those modes, B,, is the sum of the separate branching fractions, B,, for the . Phys Rev D Part Fields. 1990 Mar 1;41(5):1414-1424. . B. Aubert, R. Barate, D. Boutigny, F. Couderc, J. M. Gaillard, A. Hicheur, Y. Karyotakis, J. P. Lees, V. Tisserand, A. Zghiche, A. Palano, A. Pompili, J. C. Chen, N . 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 B . 9. The full LEP-1 data set collected with the ALEPH detector at the Z pole during 1991-1995 is analysed in order to measure the τ decay branching fractions. At present, the decay modes of the tau lepton containing l-charged particle are not completely understood. Exotic atoms 7 fs. The underlaying substructure of this decay exposes strong contribution from {rho} resonance. Submitted to Physical Review Letters . . Extensive systematic studies are performed, in order to match the large statistics of the data sample corresponding to over 300 000 measured and identified τ decays. TAU LEPTON LIFETIME AND DECAY BRANCHING RATIO MEASUREMENTS AT LEP D.G. τ decays to a K in place of a π are restricted by Cabibbo suppression (that is a small off-diagonal element of the CKM matrix will enter into the calculation of this tree level diagram) . Like the other decay modes of the tau, the hadronic decay is through the weak interaction.. Measurement of the branching ratio for the decay tau --->e- nu -bare nu tau. By using our site, you agree to our collection of information through the use of cookies. Branching fractions are obtained for the two leptonic channels and eleven . In the following, we use "branching fraction" to refer to the partial decay fraction of a particle like the τ into a specific decay mode, and "branching ratio" to refer to quantities A complete and consistent set of tau hadronic branching ratios is presented for 18 exclusive modes. The branching fraction of {tau}{sup -} {yields} 3h{sup -} 2h{sup +}{nu}{sub {tau}} is measured to be (8.56 {+-} 0.05{sub stat} {+-} 0.42{sub sys}) x 10{sup -4}. What's the branching ratio if it's only EM decay? 58. fit procedure, which has been elaborated by the Tau Physics Group within the Heavy Flavour Averaging Group (HFLAV) [1]. The branching ratio for the decay tau->e nue nutau has been measured using Z0 decay data collected by the OPAL experiment at LEP. the muon and the tau decay via the weak interaction as shown in Figure 1.1. fit procedure, which has been elaborated by the Tau Physics Group within the Heavy Flavour Averaging Group (HFLAV) [1]. The result is in good agreement with the isospin expectation but somewhat below the conserved-vector-current prediction. The sum of the . In the following, we use "branching fraction" to refer to the partial decay fraction of a particle like the τ into a specific decay mode, and "branching ratio" to refer to quantities Einj. For EM-only decay, the branching ratio would be 50% and 50%. Abstract: We present an assessment of the standard model expectations for the branching ratio of the isotopic spin and G-parity violating decay tau --> eta' pi nu_tau. Abstract The T lifetime has been measured at LEP to be T, = 294.6 ± 3. In total 33073 tau->e nue nutau candidates were identified from a sample of 186197 selected tau decays, giving a branching ratio of 17.81 +- 0.09(stat) +_ 0.06(sys)%. A particular emphasis of the Workshop was a detailed examination of the '1-prong problem': the discrepancy between the inclusive measurement of one-charged-particle decay branching ratio and . D. S. Akerib, B. Barish, M. Chadha, D. F. Cowen, G. Eigen, J. S. Miller, J. Urheim, A. J. Weinstein, D. Acosta, G. Masek, B. Ong, H. Paar, M. Sivertz, A. Bean, J . Hadronic decays of tau lepton (at . The one- and three-charged-particle inclusive branching ratios of the tau decay are measured to be B/sub 1/ = (84.7 +- 1.0)% and B/sub 3/ = (15.1 +- 1.0)%, where B/sub 1/+B/sub 3/ is constrained to be 99.85%. In total 33073 tau->e nue nutau candidates were identified from a sample of 186197 selected tau decays, giving a branching ratio of 17.81 +- 0.09(stat) +_ 0.06(sys)%. A detailed study of the systematics entering the$\pi^0$ reconstruction is also given. Since tau muons are too heavy, only e+/e- and mu+/mu- pairs are produced at 50% branching ratio. More than 12%, as a correct solution for (a) will show. Included in this study is the first direct measurement of radiative tau decay. . 3 A study of the muon decay channel of the r lepton with the presence of a pho- . By recalling the definitions of a branching ratio and partial width Γf, Pf =Γf /Γ, one can rewrite: 2 Γ=fff2()πρVM0 • This is how theorists calculate partial widths if they know how to calculate a matrix element responsible for the decay (as we will see, decays and scatterings look very much alike). branching ratio, BL. We have searched for resonance substructure in the decay. The branching ratio of the common purely leptonic tau decays are: 17.82% for decay into a tau neutrino, electron and electron antineutrino; 17.39% for decay into a tau neutrino, muon and muon antineutrino. Measurement of the branching ratio for the decay tau --->e- nu -bare nu tau. For EM-only decay, the branching ratio would be 50% and 50%. Most. Part (b) Strong interaction is more likely to occur, since only 12% of total reaction can be attributed to EM interaction. Academia.edu uses cookies to personalize content, tailor ads and improve the user experience. Use this to calculate the ratio of following decays: Γ(µ−→ e−¯ν eν µ) Γ(τ−→ e−ν¯ τν µ) How does this relate to the lifetime of the tau lepton? The measured leptonic branching fractions correspond to a tau lifetime of (3.0 +- 0.2) x 10/sup -13/ s. Secondly, the total branching fraction to one charged hadron plus at least one neutral particle is measured to be (7 +- 3)% higher than the branching fraction expected from a combination of previous measurements and theoretical predictions. B-factory branching fraction measurements of major τ-decay modes. The comparison of the tau lifetime and leptonic branching fractions with the muon lifetime gives a direct measurement of the ratios gτ /ge and gτ /gµ . The only energy scale for muon or tau decay is the mass of the decaying lepton (m µin Q4; m τin Q5). Enter the email address you signed up with and we'll email you a reset link. There are more decay modes that can happen via the electromagnetic interaction. U.S. Department of Energy Office of Scientific and Technical Information. This result is combined with other measurements to test e-mu and mu-tau universality in charged . -3- the branching fractions for the decay modeτ−→ π−π+π−π0ντ is determined mostly from experimental measurements of the branching fraction forτ−→ h−h−h+π0ντand measurements of exclusive branching fractions for 3-prong modes containing charged kaons and 1π0. The similarity of values of the two branching ratios is a consequence of lepton universality. In the decay of both the muon and the tau, a virtual charged intermediate vector boson . Abachi S, Derrick M, Kooijman P . The branching fraction of a certain decay is simply defined as: where is the total width of the particle A. Jan 9, 2015. 470. The estimate is based on a vector and scalar meson dominance parametrization of the relevant form factors, that explicitly accounts for pi^0-eta-eta' mixing. The branching fractions of the dominant hadronic tau decays are:. At present, the decay modes of the tau lepton containing l-charged particle are not completely understood. The similarity of values of the two branching fractions is a consequence of lepton universality . (The lifetime of the muon is given in Q4, and the masses of the tau and muon are on the particle handout.) The decay vertex reconstruction method Background 0.5 0.6 I .o Tracking Resolution 0.5 2.6 1.o Decays of the tau with three charged particles in Alignment 0.4 0.5 1.o the final state have been used to measure the lifetime Branching Ratios/Polarisation 0.3 0.7 I.0 Particle Misidentification 0.1 by reconstructing the secondary vertex and . Epub 2008 Apr 21. This result, together with precise measurements of the leptonic decay branching ratios of the T This plot shows decay for decay constant (λ) of 25, 5, 1, 1/5, and 1/25 for x from 0 to 5. The corresponding spectral function for the decay τ¯→πv τ is given by: (2) Equation 1 and 2 gives: (3) The muonic tau decay width for pion is given by: (4) Equation 3 and 4 reduces to: (5) Therefore, the branching fraction of the pionic tau decay is determined by the pion and tau life times (τ π and τ): Branching fractions from the constrained fit are derived from a set of basis modes. The branching fractions of the common purely leptonic tau decays are: 17.82% for decay into a tau neutrino, electron and electron antineutrino; 17.39% for decay into a tau neutrino, muon, and muon antineutrino. We find the ratio of the measured r + pyv~ branching fraction to the expected value from QED to be 1.03 f 0.44. Charlton PPE Division, CERN, 1211 Geneva 23, Switzerland. #3. 1f-i): decays into gauge boson pairs, that is, W bosons with a probability, or branching fraction, of 22%, Z bosons 3%, photons (γ . unscientific said: Strong interaction is more likely to occur, since only 12% of total reaction can be attributed to EM interaction. This discrepancy _ 'is derived from about 60 different measurements of branching fractions and some . 1. The third column of branching ratios listed in Table 3 are the results of this . Symbolically, this process can be expressed by the following differential equation, where N is the quantity and λ (lambda) is a positive rate called . Enter the email address you signed up with and we'll email you a reset link. [1-4] By definition, the total branching fraction for those modes, B,, is the sum of the separate branching fractions, B,, for the . branching ratio, BL. Since the tauonic lepton number is conserved in weak decays, a tau neutrino is created when a tau decays to a muon or an electron. . The U.S. Department of Energy's Office of Scientific and Technical Information A quantity is subject to exponential decay if it decreases at a rate proportional to its current value. Thus the. CiteSeerX - Document Details (Isaac Councill, Lee Giles, Pradeep Teregowda): In the measured decay properties of the tau there is a discrepancy between the total branching fraction for the one charged particle decay modes and the sum of the branching fractions for the known individual modes. Thus, the total B. Niczyporuk, T. Zełudziewicz, K. W. Chen, R. Hartung, H. Vogel, H. Wegener, J. K. Bienlein, R. Graumann, J. Krüger, M. Leissner, C. Rippich, M. Schmitz, E. Filos . Search terms: Advanced search options. discrepancy between the inclusive branching fraction and the sum of the exclusive branching fractions to final states containing one charged particle. For example, the average ratio of systematic to statisti-cal uncertainty of the B-factory measurements of τ branching fractions larger than 10−3 is 10.4, while the average ratio for branching fractions smaller than 10−4 is 0.8. B. Niczyporuk, T. Zełudziewicz, K. W. Chen, R. Hartung, H. Vogel, H. Wegener, J. K. Bienlein, R. Graumann, J. Krüger, M. Leissner, C. Rippich, M. Schmitz, E. Filos . The measured leptonic branching fractions correspond to a tau lifetime of (3.0 zt 0.2) x 10 -13 s which is slightly longer than the average measured tau lifetime of (2.8 rt 0.2) x IO-l3 s.

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