High-precision measurement of polarized-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi>Σ</mml:mi></mml:mrow><mml:mrow><mml:mi mathvariant="normal">−</mml:mi></mml:mrow></mml:msup></mml:mrow></mml:math>beta decay

Hsueh, S.; Müller, D.; Tang, J.; Winston, R.; Zapalac, G.; Swallow, E. C.; Berge, J. P.; Brenner, A. E.; Cooper, P. S.; Grafström, P.; Jastrzembski, E.; Lach, J.; Marriner, J. P.; Raja, R.; Smith, V. J.; McCliment, E.; Newsom, C. R.; Anderson, E. W.; Denisov, A.; Grachev, V. T.; Schegelsky, V. A.; Seliverstov, D. M.; Смирнов, Н. Н.; Terentyev, N.; Tkatch, I. I.; Vorobyov, A. A.; Razis, P. A.; Teig, L. J.

doi:10.1103/physrevd.38.2056

Cited by 91 publications

(88 citation statements)

References 41 publications

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“…from Ref. [10], as well as with the SU(3)-breaking analysis of Ref. [11], and with the value g 3 (0)/f 1 (0) = 5.5 ± 0.9, obtained using the axial Ward Identity and the generalized Goldberger-Treiman relation [12], which relates g 3 (0) with g 1 (0) in the chiral limit.…”

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confidence: 58%

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First lattice QCD study of the axial and vector form factors with breaking corrections

et al. 2007

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We present the first quenched lattice QCD study of the form factors relevant for the hyperon semileptonic decay Σ − → n ℓ ν. The momentum dependence of both axial and vector form factors is investigated and the values of all the form factors at zero-momentum transfer are presented. Following the same strategy already applied to the decay K 0 → π − ℓ ν, the SU(3)-breaking corrections to the vector form factor at zero-momentum transfer, f 1 (0), are determined with great statistical accuracy in the regime of the simulated quark masses, which correspond to pion masses above ≈ 0.7 GeV. Besides f 1 (0) also the axial to vector ratio g 1 (0)/f 1 (0), which is relevant for the extraction of the CKM matrix element V us , is determined with significant accuracy. Due to the heavy masses involved, a polynomial extrapolation, which does not include the effects of meson loops, is performed down to the physical quark masses, obtaining f 1 (0) = −0.948 ± 0.029 and g 1 (0)/f 1 (0) = −0.287 ± 0.052, where the uncertainties do not include the quenching effect. Adding a recent nextto-leading order determination of chiral loops, calculated within the Heavy Baryon Chiral Perturbation Theory in the approximation of neglecting the decuplet contribution, we obtain f 1 (0) = −0.988 ± 0.029 lattice ± 0.040 HBChPT . Our findings indicate that SU(3)-breaking corrections are moderate on both f 1 (0) and g 1 (0). They also favor the experimental scenario in which the weak electricity form factor, g 2 (0), is large and positive, and correspondingly the value of |g 1 (0)/f 1 (0)| is reduced with respect to the one obtained with the conventional assumption g 2 (q 2 ) = 0 based on exact SU(3) symmetry.

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confidence: 58%

“…22. Note that experiments carried out with polarized Σ − hyperons [10] have determined the f.f. combination |g 1 (0)/f 1 (0)−0.133 g 2 (0)/f 1 (0)| to be equal to 0.327 ± 0.007 stat.…”

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confidence: 99%

First lattice QCD study of the axial and vector form factors with breaking corrections

et al. 2007

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“…We obtain Vus = 0.2250 (27), where the quoted uncertainty is purely experimental. This value is of similar experimental precision to the one derived from K l3 , but it is higher and thus in better agreement with the unitarity requirement, |V ud | 2 + |Vus| 2 + |V ub | 2 = 1.…”

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confidence: 99%

“…While the data are not yet sufficiently precise to yield good quantitative information, one may nevertheless look for trends. In polarized Σ − → p e −ν [27], negative values of g 2 /f 1 are clearly disfavored (a positive value is preferred by 1.5σ). Since the same experiment unambiguously established that g 1 /f 1 is negative one concludes that allowing for nonvanishing g 2 would increase the derived value of V 2 us f 2 1 .…”

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confidence: 99%

Semileptonic Hyperon Decays and Cabibbo-Kobayashi-Maskawa Unitarity

Cabibbo¹,

2004

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Using a technique that is not subject to first-order SU (3) symmetry breaking effects, we determine the Vus element of the CKM matrix from data on semileptonic hyperon decays. We obtain Vus = 0.2250 (27), where the quoted uncertainty is purely experimental. This value is of similar experimental precision to the one derived from K l3 , but it is higher and thus in better agreement with the unitarity requirement, |V ud | 2 + |Vus| 2 + |V ub | 2 = 1. An overall fit including the axial contributions, and neglecting SU (3) breaking corrections, yields F + D = 1.2670 ± 0.0035 and F − D = −0.341 ± 0.016 with χ 2 = 2.96/3 d.f. The determination of the elements of the CabibboKobayashi-Maskawa (CKM) matrix [1, 2] is one of the main ingredients for evaluating the solidity of the standard model of elementary particles. This is a vast subject which has seen important progress with the determination [3,4] of ǫ ′ /ǫ and the observation [5,6] of CP violation in B decays.While a lot of attention has recently been justly devoted to the higher mass sector of the CKM matrix, it is the low mass sector, in particular V ud and V us where the highest precision can be attained. The most sensitive test of the unitarity of the CKM matrix is provided by the relation |V ud | 2 + |V us | 2 + |V ub | 2 = 1 − ∆. Clearly the unitarity condition is ∆ = 0. The |V ub | 2 contribution [7] is negligible ( 10 −5 ) at the current level of precision. The value V ud = 0.9740 ± 0.0005 is obtained from superallowed pure Fermi nuclear decays [8]. In combination with V us = 0.2196 ± 0.0023, derived from K e3 decay [9,10], this yields ∆ = 0.0032 ± 0.0014. On its face, this represents a 2.3 standard deviation departure from unitarity [8].In this communication we reconsider the contribution that the hyperon beta decays can give to the determination of V us . The conventional analysis of hyperon beta decay in terms of the parameters F, D and V us is marred * To be published in Physical Review Letters.by the expectation of first order SU (3) breaking effects in the axial-vector contribution. The situation is only made worse if one introduces adjustable SU (3) breaking parameters as this increases the number of degrees of freedom and degrades the precision. If on the contrary, as we do here, one focuses the analysis on the vector form factors, treating the rates and g 1 /f 1 [11] as the basic experimental data, one has directly access to the f 1 form factor for each decay, and this in turn allows for a redundant determination of V us . The consistency of the values of V us determined from the different decays is a first confirmation of the overall consistency of the model. A more detailed version of this work will be published in the Annual Reviews of Nuclear and Particle Sciences [12].In 1964 Ademollo and Gatto proved [13] that there is no first-order correction to the vector form factor, ∆ 1 f 1 (0) = 0. This is an important result: since experiments can measure V us f 1 (0), knowing the value of f 1 (0) in ∆S = 1 decays is essential for determining V us .The A...

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“…The combination F + D yields the nucleon axial charge, g A = 1.2695(29) [22], while the combination F − D is related to the ratio of the zeromomentum form factors for semileptonic hyperon decay, g 1 / f 1 [23]. The LECs can be calculated at leading order from the proton to vacuum matrix elements.…”

Section: Partial Proton Decay Widthmentioning

confidence: 99%

Proton lifetime bounds from chirally symmetric lattice QCD

Cooney¹

2009

Proceedings of the XXVI International Symposium on Lattice Field Theory — PoS(LATTICE 2008)

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We present results for the matrix elements relevant for proton decay in Grand Unified Theories (GUTs). The calculation is performed at a fixed lattice spacing a −1 = 1.73(3) GeV using 2+1 flavors of domain wall fermions on lattices of size 16 3 × 32 and 24 3 × 64 with a fifth dimension of length 16. We use the indirect method which relies on an effective field theory description of proton decay, and we estimate the low energy constants, α = −0.0112(25) GeV 3 and β = 0.0120(26) GeV 3 . We relate these low energy constants to the proton decay matrix elements using leading order chiral perturbation theory.

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High-precision measurement of polarized-Σ−beta decay

Cited by 91 publications

References 41 publications

First lattice QCD study of the axial and vector form factors with breaking corrections

First lattice QCD study of the axial and vector form factors with breaking corrections

Semileptonic Hyperon Decays and Cabibbo-Kobayashi-Maskawa Unitarity

Proton lifetime bounds from chirally symmetric lattice QCD

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