摘要
Recently, Cai and Su [Phys. Rev. D 81 （2010） 103514] found that the sign of interaction Q in＇the dark sector changed in the approximate redshift range of 0.45 ≤ z ≤0.9, by using a modeMndependent method to deal with the observational data. In fact, this result raises a remarkable problem, since most of the familiar interactions cannot change their signs in the whole cosmic history. Motivated by the work of Cai and Su, we have proposed a new type of interaction in a previous work [H. Wei, Nucl. Phys. B 845 （2011） 381]. The key ingredient is the deceleration parameter q in the interaction Q, and hence the interaction Q can change its sign when our universe changes from deceleration （q 〉0） to acceleration （q 〈 0）. In the present work, we consider the cosmologicai constraints on this new type of sign-changeable interactions, by using the latest observational data. We find that the cosmological constraints on the model parameters are fairly tight. In particular, the key parameter β can be constrained to a narrow range.
基金
Supported in part by National Natural Science Foundation of China under Grant No. 10905005
the Excellent Young Scholars Research Fund of Beijing Institute of Technology
the Fundamental Research Fund of Beijing Institute of Technology
