Abstract
Hadronic τ decays provide several ways to extract the Cabbibo-Kobashi-Maskawa (CKM) matrix element V us . The most precise determination involves using inclusive τ decays and requires as input the total branching ratio into strange final states. Recent results from B-factories have led to a discrepancy of about 3.4σ from the value of V us implied by CKM unitarity and direct determination from Kaon semi-leptonic modes. In this paper we predict the three leading strange τ branching ratios, using dispersive parameterizations of the hadronic form factors and taking as experimental input the measured Kaon decay rates and the τ → Kπν τ decay spectrum. We then use our results to reevaluate V us , for which we find |V us | = 0.2207 ± 0.0027, in better agreement with CKM unitarity.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
E. Braaten, S. Narison and A. Pich, QCD analysis of the tau hadronic width, Nucl. Phys. B 373 (1992) 581 [INSPIRE].
Heavy Flavor Averaging Group collaboration, Y. Amhis et al., Averages of B-Hadron, C-Hadron and tau-lepton properties as of early 2012, arXiv:1207.1158 [INSPIRE].
V. Bernard, D. Boito and E. Passemar, Dispersive representation of the scalar and vector Kπ form factors for τ → Kπν τ and K l3 decays, Nucl. Phys. Proc. Suppl. 218 (2011) 140 [arXiv:1103.4855] [INSPIRE].
V. Bernard, D.R. Boito and E. Passemar, Combined analysis of τ → Kπν τ , K ℓ3 decays and πK scattering: towards a fully consistent determination of f +(0)|V us |, work in preparation (2013).
E. Gamiz, M. Jamin, A. Pich, J. Prades and F. Schwab, Determination of m s and |V us | from hadronic tau decays, JHEP 01 (2003) 060 [hep-ph/0212230] [INSPIRE].
E. Gamiz, M. Jamin, A. Pich, J. Prades and F. Schwab, V us and m s from hadronic τ decays, Phys. Rev. Lett. 94 (2005) 011803 [hep-ph/0408044] [INSPIRE].
M. Antonelli et al., An evaluation of |V us | and precise tests of the Standard Model from world data on leptonic and semileptonic kaon decays, Eur. Phys. J. C 69 (2010) 399 [arXiv:1005.2323] [INSPIRE].
Particle Data Group collaboration, J. Beringer et al., Review of Particle Physics (RPP), Phys. Rev. D 86 (2012) 010001 [INSPIRE].
W.J. Marciano and A. Sirlin, Radiative corrections to π ℓ2 decays, Phys. Rev. Lett. 71 (1993) 3629 [INSPIRE].
J. Erler, Electroweak radiative corrections to semileptonic τ decays, Rev. Mex. Fis. 50 (2004) 200 [hep-ph/0211345] [INSPIRE].
R. Decker and M. Finkemeier, Radiative corrections to the decay τ → π(K)ν τ , Phys. Lett. B 316 (1993) 403 [hep-ph/9307372] [INSPIRE].
V. Cirigliano, M. Knecht, H. Neufeld, H. Rupertsberger and P. Talavera, Radiative corrections to K l3 decays, Eur. Phys. J. C 23 (2002) 121 [hep-ph/0110153] [INSPIRE].
V. Cirigliano, H. Neufeld and H. Pichl, K e3 decays and CKM unitarity, Eur. Phys. J. C 35 (2004) 53 [hep-ph/0401173] [INSPIRE].
P. Buettiker, S. Descotes-Genon and B. Moussallam, A new analysis of πK scattering from Roy and Steiner type equations, Eur. Phys. J. C 33 (2004) 409 [hep-ph/0310283] [INSPIRE].
A. Pich and J. Portoles, The vector form-factor of the pion from unitarity and analyticity: a model independent approach, Phys. Rev. D 63 (2001) 093005 [hep-ph/0101194] [INSPIRE].
D.R. Boito, R. Escribano and M. Jamin, Kπ vector form-factor, dispersive constraints and τ → ν τ Kπ decays, Eur. Phys. J. C 59 (2009) 821 [arXiv:0807.4883] [INSPIRE].
D. Boito, R. Escribano and M. Jamin, Kπ vector form factor constrained by τ → Kπν τ and K l3 decays, JHEP 09 (2010) 031 [arXiv:1007.1858] [INSPIRE].
M. Jamin, A. Pich and J. Portoles, Spectral distribution for the decay τ → ν τ Kπ, Phys. Lett. B 640 (2006) 176 [hep-ph/0605096] [INSPIRE].
M. Jamin, A. Pich and J. Portoles, What can be learned from the Belle spectrum for the decay τ − → ν τ K S π −, Phys. Lett. B 664 (2008) 78 [arXiv:0803.1786] [INSPIRE].
G. Gounaris and J. Sakurai, Finite width corrections to the vector meson dominance prediction for ρ → e + e −, Phys. Rev. Lett. 21 (1968) 244 [INSPIRE].
L. Beldjoudi and T.N. Truong, τ → πKν decay and πK scattering, Phys. Lett. B 351 (1995) 357 [hep-ph/9411423] [INSPIRE].
B. Moussallam, Analyticity constraints on the strangeness changing vector current and applications to τ → Kπν τ , τ → Kππν τ , Eur. Phys. J. C 53 (2008) 401 [arXiv:0710.0548] [INSPIRE].
V. Bernard, M. Oertel, E. Passemar and J. Stern, \( K_{{\mu 3}}^L \) decay: a stringent test of right-handed quark currents, Phys. Lett. B 638 (2006) 480 [hep-ph/0603202] [INSPIRE].
V. Bernard, M. Oertel, E. Passemar and J. Stern, Dispersive representation and shape of the K l3 form factors: robustness, Phys. Rev. D 80 (2009) 034034 [arXiv:0903.1654] [INSPIRE].
Belle collaboration, D. Epifanov et al., Study of τ − → K S π − ν τ decay at Belle, Phys. Lett. B 654 (2007) 65 [arXiv:0706.2231] [INSPIRE].
BaBar collaboration, S. Paramesvaran, Selected topics in τ physics from BaBar, arXiv:0910.2884 [INSPIRE].
Belle II collaboration, T. Abe, Belle II Technical Design Report, arXiv:1011.0352 [INSPIRE].
V. Cirigliano, M. Giannotti and H. Neufeld, Electromagnetic effects in K l3 decays, JHEP 11 (2008) 006 [arXiv:0807.4507] [INSPIRE].
V. Cirigliano, G. Ecker and H. Neufeld, Isospin violation and the magnetic moment of the muon, Phys. Lett. B 513 (2001) 361 [hep-ph/0104267] [INSPIRE].
V. Cirigliano, G. Ecker and H. Neufeld, Radiative τ decay and the magnetic moment of the muon, JHEP 08 (2002) 002 [hep-ph/0207310] [INSPIRE].
G. Colangelo et al., Review of lattice results concerning low energy particle physics, Eur. Phys. J. C 71 (2011) 1695 [arXiv:1011.4408] [INSPIRE].
V. Cirigliano et al., Towards a consistent estimate of the chiral low-energy constants, Nucl. Phys. B 753 (2006) 139 [hep-ph/0603205] [INSPIRE].
A. Kastner and H. Neufeld, The K l3 scalar form factors in the standard model, Eur. Phys. J. C 57 (2008) 541 [arXiv:0805.2222] [INSPIRE].
K. Maltman and C.E. Wolfe, V us from hadronic tau decays, Phys. Lett. B 639 (2006) 283 [hep-ph/0603215] [INSPIRE].
E. Gamiz, M. Jamin, A. Pich, J. Prades and F. Schwab, Theoretical progress on the V us determination from tau decays, PoS(KAON)008 [arXiv:0709.0282] [INSPIRE].
K. Maltman, A Critical look at V us determinations from hadronic τ decay data, Nucl. Phys. Proc. Suppl. 218 (2011) 146 [arXiv:1011.6391] [INSPIRE].
J. Hardy and I. Towner, Superallowed 0+ → 0+ nuclear beta decays: a new survey with precision tests of the conserved vector current hypothesis and the standard model, Phys. Rev. C 79 (2009) 055502 [arXiv:0812.1202] [INSPIRE].
V. Mateu and A. Pich, V us determination from hyperon semileptonic decays, JHEP 10 (2005) 041 [hep-ph/0509045] [INSPIRE].
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Antonelli, M., Cirigliano, V., Lusiani, A. et al. Predicting the τ strange branching ratios and implications for V us . J. High Energ. Phys. 2013, 70 (2013). https://doi.org/10.1007/JHEP10(2013)070
Received:
Accepted:
Published:
DOI: https://doi.org/10.1007/JHEP10(2013)070