نتایج جستجو برای: quark

تعداد نتایج: 30103  

Journal: :journal of sciences, islamic republic of iran 2009
h. mehrban

in this research we work with the effective hamiltonian and the quark model. we investigate the decay rates of matter-antimatter of quark. we describe the effective hamiltonian theory and apply this theory to the calculation of current-current ( ), qcd penguin ( ), magnetic dipole ( ) and electroweak penguin ( ) decay rates. the gluonic penguin structure of hadronic decays is studied through th...

In this research, we are going to study the QCD penguin structure and calculate the second order approximation. The amplitude of decays related to QCD penguin in the quark model up to the first and second orders were calculated. We calculated the amplitude of QCD penguin on lowest order of αs for the first order of the decay processes b→qkg→qkqiqj and for the second order of the decay processes...

In this research we described the effective Hamiltonian theory and applied this theory to the calculation of current-current (Q1,2) and QCD penguin (Q3,…,6) c quark decay rates. We calculated the decay rates of semileptonic and hadronic of charm quark in the effective Hamiltonian theory. We investigated the decay rates of D meson decays according to Spectator Quark Model (SQM) for the calculati...

رجبی , علی اکبر, شجاعی , محمدرضا,

  In this article nucleons are discussed based on constituent quark model. This model aims at studying the forces among three particles and the corresponding standard two-body potential contribution. The quark potential contains a hypercentral interaction. The confining potential is composed of four components,color charge, the oscillatory potential, the interaction quark and neutral gluon, and...

1993
Yu-Qi Chen Yu-Ping Kuang

A set of general relations between the spin-independent and spin-dependent potentials of heavy quark and anti-quark interactions are derived from reparameterization invariance in the Heavy Quark E ective Theory. It covers the Gromes relation and includes some new interesting relations which are useful in understanding the spin-independent and spin-dependent relativistic corrections to the leadi...

Journal: :Physical review. D, Particles and fields 1994
Fadin Fiore Quartarolo

One loop corrections to the coupling of the reggeized gluon to quarks are calculated in QCD. Combining this result with the known corrections to the gluon-gluon-reggeon vertex, we check the self-consistency of the representation of the amplitudes with gluon quantum numbers and negative signature in the t-channel in terms of Regge pole contribution. 1. Introduction Since a long time it has been ...

بردبار, غلامحسین, خسروپور, بهروز, نورافشان, مریم,

In this paper, we have considered that the strange-star consists of quark matter from its center to surface. For quark matter, we have used two models, the MIT bag model and string-flip like model. In the bag model, the energy of the system has been considered the kinetic energy of the particles of system in addition to a constant B. We have considered two states for B, one of them is constant...

Journal: :Physical review. D, Particles and fields 1994
Jakob

Independent multiple scattering (‘Landshoff’) contributions to proton-proton elastic scattering at wide angles are calculated in the quark-diquark model. Results confirm previous observations about the magnitude of these contributions. The use of the quark-diquark model extends the applicability of perturbative QCD calculations down to lower values of momentum transfer substantially. 12.38.Bx, ...

2001
Kevin Cahill

In the physical vacuum of QCD, the energy density of lightquark fields strongly coupled to slowly varying gluon fields can be negative. The states that drive this energy density lowest are condensates of pairs of quarks and antiquarks of nearly opposite momenta. These quark-antiquark condensates break chiral symmetry.

This research, works with the effective Hamiltonian and the quark model. Using, the decay rates of matter-antimatter of b quark was investigated. We described the effective Hamiltonian theory which was applied to the calculation of current-current (Q1,2), QCD penguin (Q3,…,6), magnetic dipole (Q8) and electroweak penguin (Q7,…,10) decay rates. The gluonic penguin structure of hadronic decays ...

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