Spin Symmetry Without Heavy Quarks : Hyperon Form Factors In
نویسنده
چکیده
In the large N c limit, all hyperon decays involving the same quark diagram Q ! Q 0 are described by a single weak form factor QQ 0(w). No assumption on the mass of Q or Q 0 is necessary, making our results applicable to both b ! c and c ! s transitions. This same form factor describes both Q ! Q 0 and () Q ! () Q 0 transitions. The (non-)commutativity between the heavy quark and the large N c limits is brieey discussed under the deenite example of b ! c decay.
منابع مشابه
ar X iv : h ep - p h / 00 11 31 2 v 1 2 5 N ov 2 00 0 1 Hyperon semileptonic decay constants and quark - spin content of the octet baryons
We present the recent investigation on the effect of the SU(3) symmetry breaking in the spin structure of the octet baryons. The spin structure of the nucleon has been a hot issue since the measurement of the first moment of the proton spin structure function g p 1 [1] by the European Muon Collaboration (EMC). The EMC result indicates that the strange quark is polarized in the opposite directio...
متن کاملHeavy Hyperon–Antihyperon Production
Based on the experience from the production of light antihyperon–hyperon (Λ̄Λ, Σ̄Σ) pairs at LEAR (experiment PS185) it is suggested to continue the investigations towards the heavier antihyperon–hyperon pairs Ξ̄Ξ and Ω̄Ω in view of: 1. the production dynamics of the heavier antihyperon–hyperon out of the p̄p annihilation 2. a comparison of the ”(3 s) (3 s̄)”– quark system Ω̄Ω to the 3 (s̄s) = 3 φ meso...
متن کاملHow to Use Weak Decays in Analyses of Data on Nucleon Spin Structure Functions
The use of weak decays to determine proton spin structure is examined in view of possible violations of the Bjorken and Gottfried Sum rules, flavor symmetry breaking and flavor asymmetry in the sea. The use of the neutron decay is found to be unaffected by all these. A method for including these effects in analyses of hyperon decays shows that a flavor-asymmetric sea produced by SU(3) symmetry ...
متن کاملGlobal polarization of QGP in non-central heavy ion collisions at high energies
Due to the presence of a large orbital angular momentum of the parton system produced at the early stage of non-central heavy-ion collisions, quarks and anti-quarks are shown to be polarized in the direction opposite to the reaction plane which is determined by the impact-parameter and the beam momentum. The global quark polarization via elastic scattering was first calculated in an effective s...
متن کاملF/D ratio in hyperon beta decays and the spin distribution in the nucleon.
It is shown that hyperon beta decay data can be well accommodated within the framework of Cabbibo’s SU(3) symmetric description if one allows for a small SU(3) symmetry breaking proportional to the mass difference between strange and nonstrange quarks. The F/D ratio does not depend sensitively on the exact form of the symmetry-breaking, and the best fits are close to the value previously used i...
متن کامل