Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Study of tau decays involving kaons, spectral functions and determination of the strange quark mass
AU - ALEPH Collaboration, The
AU - Barate, R.
AU - Betteridge, Andrew
AU - Bowdery, Christopher
AU - Colrain, Paul
AU - Finch, Alexander
AU - Foster, Frank
AU - Hughes, Gareth
AU - Jones, Roger
AU - Williams, Mark
PY - 1999/12
Y1 - 1999/12
N2 - All ALEPH measurements of branching ratios of τ decays involving kaons are summarized including a combination of results obtained with K0S and K0L detection. The decay dynamics are studied, leading to the determination of contributions from vector K∗(892) and K∗(1410) , and axial-vector K1(1270) and K1(1400) resonances. Agreement with isospin symmetry is observed among the different final states. Under the hypothesis of the conserved vector current, the spectral function for the KK¯¯¯π mode is compared with the corresponding cross section for low energy e+e− annihilation, yielding an axial-vector fraction of (94+6−8)% for this mode. The branching ratio for τ decay into all strange final states is determined to be B(τ−→X−(S=−1)ντ)=(28.7±1.2)×10−3 . The measured mass spectra of the strange τ decay modes are exploited to derive the S=−1 spectral function. A combination of strange and nonstrange spectral functions is used to determine the strange quark mass and nonperturbative contributions to the strange hadronic width. A method is developed to avoid the bad convergence of the spin zero hadronic component, with the result ms(M2τ)=(176+46−57) MeV/ c2 . The evolution down to 1 GeV gives ms(1GeV2)=(234+61−76)MeV/c2 .
AB - All ALEPH measurements of branching ratios of τ decays involving kaons are summarized including a combination of results obtained with K0S and K0L detection. The decay dynamics are studied, leading to the determination of contributions from vector K∗(892) and K∗(1410) , and axial-vector K1(1270) and K1(1400) resonances. Agreement with isospin symmetry is observed among the different final states. Under the hypothesis of the conserved vector current, the spectral function for the KK¯¯¯π mode is compared with the corresponding cross section for low energy e+e− annihilation, yielding an axial-vector fraction of (94+6−8)% for this mode. The branching ratio for τ decay into all strange final states is determined to be B(τ−→X−(S=−1)ντ)=(28.7±1.2)×10−3 . The measured mass spectra of the strange τ decay modes are exploited to derive the S=−1 spectral function. A combination of strange and nonstrange spectral functions is used to determine the strange quark mass and nonperturbative contributions to the strange hadronic width. A method is developed to avoid the bad convergence of the spin zero hadronic component, with the result ms(M2τ)=(176+46−57) MeV/ c2 . The evolution down to 1 GeV gives ms(1GeV2)=(234+61−76)MeV/c2 .
U2 - 10.1007/s100520050659
DO - 10.1007/s100520050659
M3 - Journal article
VL - 11
SP - 599
EP - 618
JO - The European Physical Journal C (EPJ C) - Particles and Fields
JF - The European Physical Journal C (EPJ C) - Particles and Fields
SN - 1434-6052
IS - 4
ER -