A Study Of Baryon Magnetic Moment In Covariant Chiral Effective Theory

Quantum chromodynamics(QCD)has long been puzzled by the quark confinement.Recently,people simulate the process of strong interaction at low-energy by using the technology name lattice quantum chromodynamics(l QCD),with the help of well-developed computer technology,but the quark masses used in l QCD are normally larger then the physics one.To receive the physical value of hadron,one has to extrapolate the l QCD data into physical value with a self-consistent analytic results.For this recent,an accurate expression is necessary for the strong interaction at low-energy.Effective field theory is an possible way to study strong interaction at low-energy.Effective field theory is a low-energy approximation of QCD,it show a outstanding performance in meson problem at low-energy.However,it doesn’t work well in the baryon problem for the reason that the value of baryon mass is beyond the scope of application,namely,break the power-counting rule.People start looking for the ways to recover the power-counting,such as heavy-baryon approach,infrared regularization and Extendedon-mass-shell scheme.However,in practical application,limitations or operational complexity and excessive subtraction exist in the former two scheme,a certain problem of excessive subtraction also occur in the latter one.Recently,our research team came up with the Extended minimal subtraction(E(?)),which is simpler relatively.Extended minimal subtraction has already been discussed in the pass few years.Its applicability has been proved by the studies of one-loop diagrams correction to the octet baryon axial vector current and octet baryon mass under SU(2).Compared with other methods,E(?) seems to be more simple.To further discuss the validity and applicability of E(?),this paper will calculate the baryon mass and magnetic moment in the frame of covariant chiral perturbative theory under SU(3)using the E(?),and discuss the recovery of power-counting.We focus on the calculation of baryon mass and magnetic moment at the next-to-leading order,which are the stationary properties of baryon.We also finish the analysis of experiment data and l QCD data with the result of E(?) and extrapolate it into physical value.We show that E(?) give a reasonable theoretical and numerical result at the nextto-leading order.In the aspect of theory,E(?) seem to come up with a result that is close to the one EOMS gives.In the aspect of numerical simulation,the result E(?) achieve is better than those given by heavy-baryon approach scheme and infrared regularization,but close to the one given by EOMS.