A proposal on complementary determination of the effective electro-weak mixing angles via doubly heavy-flavored hadron production at a super Z-factory

To test the standard model(SM)precisely and to look for the clues deviating from SM,a proposal for determining the effective electro-weak mixing angles sin2θefff(particularly f=lept,c,b)is proposed.It is via observing the asymmetries(the forward-backward one AFB,the left-right one ALR and the combined left-right forward-backward one ALRFB)of the doubly heavy-flavored hadrons in the production at a super Z-factory(an e+e-collider designed with a luminosity as high as possible for modernday techniques runs around the center-of-mass energy s1/2=mZ).To see the sensitivity,uncertainties as well as the event accumulation precisely,the observables for describing the asymmetries of the produced hadrons are computed numerically with varying effective mixing angles,and based on the result analyses,it is concluded that the proposal may offer an independent complement determination of the effective mixing angles.

Production of light-flavor and single-charmed hadrons in pp collisions at√s=5.02 TeV in an equal-velocity quark combination model

We apply an equal-velocity quark combination model to study the production of light-flavor hadrons and single-charmed hadrons at midrapidity in the pp collisions at √s= 5.02 TeV. We find that the experimental data for the pT spectra of Ω and φ exhibit the quark number scaling property, which clearly indicates the quark combination mechanism at hadronization. Experimental data for the pT spectra of p,Λ,Ξ,Ω,φ and K^(+0) are systematically described by the model. The non-monotonic pT dependence of the Ω/φ ratio is naturally explained, and we find that it is closely related to the shape of the logarithm of the strange quark pT distribution. Using the pT spectra of light-flavor quarks obtained from light-flavor hadrons and the pT spectrum of charm quarks, which is consistent with perturbative QCD calculations, the experimental data for differential cross-sections of D^(0,+), D^(+)_s), and Λ^(+)_(c) as functions of p are systematically described. We predict the differential cross-sections of Ξ^(0,+)_(c) and Ω^(0)_(c) . The ratio Ξ^(0,+)_(c) /D^0) in our model is approximately 0.16, and Ω^(0)_(c) /D^(0) is approximately 0.012, owing to the cascade suppression of strangeness.In addition, the predicted Ξ^(0,+)_(c) /D^0) ratios exhibit the non-monotonic dependence on pT in the low pT range.