Pole Approximation and Unitary Symmetry in Nonleptonic Hyperon Decays

Itoh, Chiaki; Toda, Azuma

doi:10.1143/ptp.32.606

Cited by 3 publications

(4 citation statements)

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“…We now turn to the derivation of the hyperon-nucleon transition in the factorization approach. The hyperon-nucleon transition was studied in the context of the nonleptonic hyperon decay [65,92,[162][163][164][165][166][167][168][169][170][171][172][173][174]. The general form of the hyperon-nucleon transition lagrangian relevant in this work is given by…”

Section: Hyperon-nucleon Transitionmentioning

confidence: 99%

Standard model contribution to the electric dipole moment of the deuteron, 3H, and 3He nuclei

Yamanaka

Hiyama

2016

J. High Energ. Phys.

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We calculate for the first time the electric dipole moment (EDM) of the deuteron, 3 H, and 3 He nuclei generated by the one-meson exchange CP-odd nuclear force in the standard model. The effective |∆S| = 1 four-quark operators are matched to the |∆S| = 1 standard model processes involving the CP phase of the Cabibbo-KobayashiMaskawa matrix at the electroweak scale and run down to the hadronic scale µ = 1 GeV according to the renormalization group evolution in the next-to-leading logarithmic order. At the hadronic scale, the hadron matrix elements are modeled in the factorization approach. We then obtain the one-meson (pion, eta meson, and kaon) exchange CP-odd nuclear force, which is the combination of the |∆S| = 1 meson-baryon vertices which issue from the penguin operator and the hyperon-nucleon transition. From this CP-odd nuclear force, the nuclear EDM is calculated with the realistic Argonne v18 interaction and the CP-odd nuclear force using the Gaussian expansion method. It is found that the EDMs of light nuclear systems are of order O(10 −31 )e cm. We also estimate the standard model contribution to other hadronic CP violating observables such as the EDMs of 6 Li, 9 Be nuclei, and the atomic EDMs of 129 Xe, 199 Hg, 211 Rn, and 225 Ra generated through the nuclear Schiff moment. We then analyze the source of theoretical uncertainties and show some possible ways to overcome them.

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Section: Hyperon-nucleon Transitionmentioning

confidence: 99%

Standard model contribution to the electric dipole moment of the deuteron, 3H, and 3He nuclei

Yamanaka

Hiyama

2016

J. High Energ. Phys.

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“…They have obtained good relations consistent with experiments for parity-violating amplitudes, but obtained unsatisfactory results for parity-conserving amplitudes. On the other hand, SU (3) and R or RP invariance seem to explain experiments of nonleptonic baryon decays which were discussed previously. 2 …”

mentioning

confidence: 70%

“…We assume that parity-violating and parity-conserving interactions transform as (8, 1) and (8, 3) members of the 35-dimensional representations, respectively, and also assume that weak interactions are CP invariant. 56-dimensional baryons may be described by a mixture of tensors BaPr and BaPro which are symmetric with respect to the indices a, {3 and r. *l These tensors are reducible under SU(3)@SU (2) and are expressed, in the rest frame, in terms of spin wave functions and SU (3) tensors,…”

Section: Lalmentioning

confidence: 99%

SU(6) andRPInvariance in Nonleptonic Baryon Decays

Itoh

1965

Prog. Theor. Phys.

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Several authors 1 l have examined nonleptonic baryon decays in the light of the .SU(6) theory. They have obtained good relations consistent with experiments for parity-violating amplitudes, but obtained unsatisfactory results for parity-conserving amplitudes. On the other hand, SU (3) and R or RP invariance seem to explain experiments of nonleptonic baryon decays which were discussed previously. 2 l,al Therefore it is interesting to apply RP invariance to nonleptonic baryon decays in SU(6). We assume that parity-violating and parity-conserving interactions transform as (8, 1) and (8, 3) members of the 35-dimensional representations, respectively, and also assume that weak interactions are CP invariant. 56-dimensional baryons may be described by a mixture of tensors BaPr and BaPro which are symmetric with respect to the indices a, {3 and r. *l These tensors are reducible under SU(3)@SU(2) and are expressed, in the rest frame, in terms of spin wave functions and SU (3) tensors,*l Strictly speaking, the other octet b' 8 should be adopted in BaPr, and baryon octet is a mixure of two octets; M+b'l]. Because of SU(6) invariance, there appears no interference between two octets. Therefore, the ansatz of Eq. (1) is correct.Here x 1 and x 1 J' stand for spin -1/2 and -3/2 wave functions, respectively, bf, is the octet tensor, dABa is the decuplet tensor, and x is the eigenfunction of the baryon-number operator corresponding to the baryon number one. In order to restore RP invariance in quark model, we introduce (another) set N' of quarks besides the usual set N. The members of N contribute to BaPr and the members of N' contribute to BaPr· Each member of N' should have Q and Y with opposite sign to those of the corresponding member of N, but it has the same baryon number. Then RP invariant interactions, which are of derivative type in relativistic form, are expressed as follows: (We only write down the terms which contribute to pionic decays of hyperons.) Hp.v. =A1BaP(3, mlM 1 ( 2 ,m) ,BaPr -AlJ3aPrM 1 / 2 ·'"')BaP(3, m) + A2BaP(3, m)MIP P1 BaPI(2.m) -A2JiaPI(2.m) M~,P BaP(3o m) + h.c., Hp. 6 .=BJJ,xPC3 0 m)M( 2 .ml,BaPr + BJJaPr Mi2,m) BaP(3, m) + B2BaP(3, m)MP p' BaPI(2,m) + B 2J3aPI( 2 ,m) Mp1p BaP(3, m) + h.c.,(2) where (we neglect q 2 /(mf+Ef) compared with m, where m is the meson energy). **J We define the upper and lower tensor suffixes as follows.P.ttB=PBA=PIJt, d;l=dij= djj.

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“…2 ) We introduce two models to explain the r-decay processes in SU(3); (i) the process, Hyperon~Baryon+p 0 (or u}) is followed by p 0 ->r (or u}->r) , 1 ), 5 ) as in Figs We may assume the following Hamiltonian H 7 for the r decay of hyperon…”

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confidence: 99%

Weak Gamma Decays of Hyperons

Itoh

1965

Prog. Theor. Phys.

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\V e investigate weak gamma decays of hyperons. The gamma rays can have directional asymmetry and polarization. They depend on the asymmetry parameter a. Assuming RP in variance, SU (3) and the pole approximation, we discuss two models ; (i) the process, Hyperon->Baryon+ p 0 (or wO) is followed by pD->y(or wD-o.y); (ii) the decay amplitude must transform like A 1 1 -l/2 A 2 2-l/2 A 3 3 • Under one additional condition, the model (i) is reduced to the model (ii). In the model (ii), the decay rate w (1:+-~f..> + r) has the largest value among many possible weak gamma decays of hyperons.

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Pole Approximation and Unitary Symmetry in Nonleptonic Hyperon Decays

Cited by 3 publications

References 1 publication

Standard model contribution to the electric dipole moment of the deuteron, 3H, and 3He nuclei

Standard model contribution to the electric dipole moment of the deuteron, 3H, and 3He nuclei

SU(6) andRPInvariance in Nonleptonic Baryon Decays

Weak Gamma Decays of Hyperons

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