Nonleptonic Hyperon Decay in the Quark Model

Miura, Kimio; Minamikawa, Toshiyuki

doi:10.1143/ptp.38.954

Cited by 47 publications

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“…Further, no two quarks of the same baryon with the same helicity should end (or originate) in the weak vertex. This follows from the fact that coloured quarks effectively behave as bosons in baryons [16] and thus, from the (V-A) (V-A) structure, the ground state quarks may only have the a,s. spin and a.s. flavour configuration in this case.…”

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confidence: 99%

Quark and particle helicities in hadronic charmed particle decays

Körner

Goldstein²

1979

Physics Letters B

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We investigate possibilities of obtaining information on the chirality of the charm-changing current ~s) by measuring the helicities of hadrons with spin in exclusive hadronic charmed particle decays.As more data on charmed particle decays are becoming available, it is desirable to obtain more detailed information on the decays than is obtainable from measurements of rates alone. In particular, since the charm changing current ~s) is believed to be lefthanded, it would be interesting to find out whether this helicity information is being handed down to hadrons with spin in the final state.For semileptonic charmed particle decays this, has been answered in the affirmative [1,2]. However, in semi.leptonic decays useful helicity information can only be collected in a limited q2.range (qu being the momentum transfer to the leptons) due to angular momentum constraints at the kinematic boundaries. Compared to these the hadronic two-body decay modes are concentrated at a "fixed" q2 = m 2 which is more favourable to a helicity analysis from rate considerations alone.We start our considerations with charmed meson decays [3,4]. The AC = AS = 1 transitions are generated by an effective hamiltonian [3 ],1 This work was supported in part by the U.S. Department of Energy. 2 Permanent address: Tufts University, Medford, M A 02155, USA. ~eff is the usual GIM current-current form renormalized at short distances by gluon exchange effects [5]. Without renormalization one has f+ =f_ = 1. The renormalized values for charmed particle decays have been calculated in ref. [3] and are given by]'_ = f+-2 = 2.15.The effective hamiltonian (1) leads to the quark transitions shown in the inset of fig. 1. These can be calculated in the quark model since the local form of (1) allows one to relate the diagrams of fig.

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confidence: 99%

Quark and particle helicities in hadronic charmed particle decays

Körner

Goldstein²

1979

Physics Letters B

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“…On the other hand, we have also no reason to ignore the A because, as we will see, we can expect unlike due to the color wave-function antisymmetry [29]. Indeed, we find these contributions very large quantitatively.…”

Section: Contribution From the Exchange Diagrammentioning

confidence: 70%

Neutron electric dipole moment in left-right-symmetric models

et al. 1992

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We discuss the neutron electric dipole moment in the SU(2)L XSU(2), X U ( 1 ) model of CP violation. We compute the leading-logarithm QCD corrections to the quark electric dipole moment. To estimate the anomalous dimensions one needs to go to two loops, like in the controversial b-+sy transition in the standard model. Since fermion loops in chiral theories need a careful treatment of regularization, we expose in detail the calculation in various dimensional-regularization schemes (naive dimensional regularization, dimensional reduction, and the 't Hooft-Veltman prescription) and also in Pauli-Villars regularization. We do not find the kind of discrepancies claimed in the literature for b -s y , and obtain the same result for all these regularizations. The QCD corrections to the dominant left-right ( L R ) exchange contribution are large and critically dependent on p and Aac-, making uncertain even its sign. We show that, in addition to the currently considered N* intermediate states, the nucleon and A also make a very large contribution. One has (

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“…Here the model II of Ref. 10) is taken for parity cm1sen·mg amplitudes. This is able to give good agreement with data except for Q-decays.…”

Section: Y Talwiwa T 1\iinamilwwa and K A1iuramentioning

confidence: 99%

Nonleptonic Decays of Charmed Baryons in the Quark Model

Takaiwa¹,

Minamikawa²,

Miura³

1976

Progress of Theoretical Physics

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Nonleptonic decays or charmed baryons are discussed in the SU (8) @SU (:'\) co1oc quark model. The Lil=l/:2 rub of hyperon decay:i is explained by 15 and 20'' dominance and charmed baryon decays occur through 20" clommantly. Also X particles of coc;m1c ray event::; are Identified \Yitb charrned baryon~ or charn1ed 1nesons, respective1y, accorc]jng tn their lifetimes, and tk: charmed baryons are assrgned to A,+(cnp) and Az 0 (cni.), 3* of C = 1, 1 ':2+ baryon:-:;. l'vfore than ten years ago, SLT ( 4) was l1rst introduced 1 l as the symmetr\" group vvhich contains SU(3) as a subgroup. Then, it hild no experimental support. However the sitwttion has be'cn changed by the cosmic ray event observed by Niu, ~Iikumo and l\!Ieacla'J in 197]. et al. 3 l have proposed that this C'.-ent indicates the existence of a new q uantc:1 number; this quzEJtum num.ber is called cha:·m. Theoretically, and IVIaiani'J (GIJ\!f) have discussed that ch.:1rmed quark is also red in oi·der to understand JS = 2 and JS=foO, JQ = 0 weak processes. ')~Lis idea has been ca rriecl out." The disco\·eries of gzruge fheorists and rnany investigations haYc .!(:3.1)"' and cj/(3.7) 7 J ha\·e stimulated mc;·e ,. ,• l·callSUC discussion~ on ~.._)[I(4) sche111e. J:\ccordin~!, to this scherne the present authors haYc discussed the nonle;1tonic t\'. .>body weak of charmed mesonf, in Lhe qu:ul~ model.sJ In a previoclS paper, GLVI weak currents ancl Okubo-Zweig-Tizuka (OZI) rule 9 l are :cssumecl and two types of clizcgrams are considered as dominant diagrams. Furti1er the rates o£ the most probable decays of ocharmed mesons hal'e been calculat::d to be of the orcleT d 10 11 sec-\ which 1s far from the lifetime, -:c=4X10-11 sec, of tl1e first e\cent observed by Niu et al. In this paper \'\'e apply the previous model to nonleptonic decays of 1/2' charmed baryons, which may be alternative candidates for the event of Niu et d. This is rather straightforward application of the first model of the present authors.81' 10l The low-lying baryons (JP=~1;2~ and 3/2~) are described as 120 representa-at Australian National University on March 13, 2015 http://ptp.oxfordjournals.org/ Downloaded from In order to calculate the amplitudes of baryon decays we ought to know the \Va\'e functions of baryons. Baryons are described as 120 ( =:J 56) of SU (8)

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Nonleptonic Hyperon Decay in the Quark Model

Cited by 47 publications

References 0 publications

Quark and particle helicities in hadronic charmed particle decays

Quark and particle helicities in hadronic charmed particle decays

Neutron electric dipole moment in left-right-symmetric models

Nonleptonic Decays of Charmed Baryons in the Quark Model

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