Let a,b be two positive integers such that a≤b and a≡b(mod 2).We say that a graph G has an(a,b)-parity factor if G has a spanning subgraph F such that dF(v)≡b(mod 2)and a≤dF(v)≤b for all v∈V(G).In this paper,we ...Let a,b be two positive integers such that a≤b and a≡b(mod 2).We say that a graph G has an(a,b)-parity factor if G has a spanning subgraph F such that dF(v)≡b(mod 2)and a≤dF(v)≤b for all v∈V(G).In this paper,we provide a tight spectral radius condition for a graph to have(a,b)-parity factors.展开更多
In the littlest Higgs model with T-parity, the heavy photon （A_H） is supposed to be a possible dark matter （DM） candidate. The direct proof of the validity of this model is to produce the heavy photon at an accele...In the littlest Higgs model with T-parity, the heavy photon （A_H） is supposed to be a possible dark matter （DM） candidate. The direct proof of the validity of this model is to produce the heavy photon at an accelerator. In this paper, we study the production rate of e~＋ e^- → AH AH at the international e~＋ e^- linear collider （ILC） in the littlest Higgs model with T-parity, and show the distributions of the transverse momenta of A H . The numerical results indicate that the heavy photon production rate could reach the 10^-1 fb level at some parameter space, so this could be a good chance to observe the heavy photon via the pair production process with high luminosity at the ILC （500 fb^-1）. We know that DM is composed of weakly interacting massive particles, so the interactions with standard model particles are weak. How to detect heavy photons at a collider and distinguish them from other DM candidates are discussed in the final section of the paper.展开更多
文摘Let a,b be two positive integers such that a≤b and a≡b(mod 2).We say that a graph G has an(a,b)-parity factor if G has a spanning subgraph F such that dF(v)≡b(mod 2)and a≤dF(v)≤b for all v∈V(G).In this paper,we provide a tight spectral radius condition for a graph to have(a,b)-parity factors.
基金Supported by National Natural Science Foundation of China (11075045)Foundation of He’nan Educational Committee(2011A140005)Youth Foundation of Xinxiang University (12ZC10)
文摘In the littlest Higgs model with T-parity, the heavy photon （A_H） is supposed to be a possible dark matter （DM） candidate. The direct proof of the validity of this model is to produce the heavy photon at an accelerator. In this paper, we study the production rate of e~＋ e^- → AH AH at the international e~＋ e^- linear collider （ILC） in the littlest Higgs model with T-parity, and show the distributions of the transverse momenta of A H . The numerical results indicate that the heavy photon production rate could reach the 10^-1 fb level at some parameter space, so this could be a good chance to observe the heavy photon via the pair production process with high luminosity at the ILC （500 fb^-1）. We know that DM is composed of weakly interacting massive particles, so the interactions with standard model particles are weak. How to detect heavy photons at a collider and distinguish them from other DM candidates are discussed in the final section of the paper.
