Following previous study,in the littlest Higgs model(LHM),the heavy photon is supposed to be a possibledark matter candidate and its relic abundance of the heavy photon is estimated in terms of the Boltzman-Lee-Weinbe...Following previous study,in the littlest Higgs model(LHM),the heavy photon is supposed to be a possibledark matter candidate and its relic abundance of the heavy photon is estimated in terms of the Boltzman-Lee-Weinbergtime-evolution equation.The effect of the T-parity violation is also considered.Our calculations show that when Higgsmass M_H taken to be 300 GeV and do not considering T-parity violation,only two narrow ranges 133<M_A_H<135 GeVand 167<M_A_H<169 GeV are tolerable with the current astrophysical observation and if 135<M_A_H<167 GeV,there must at least exist another species of heavy particle contributing to the cold dark matter.As long as the T-paritycan be violated,the heavy photon can decay into regular standard model particles and would affect the dark matterabundance in the universe,we discuss the constraint on the T-parity violation parameter based on the present data.Direct detection prospects are also discussed in some detail.展开更多
There must be electromagnetic fields created during high-energy heavy-ion collisions.Although the electromagnetic field may become weak with the evolution of the quark-gluon plasma(QGP),compared to the energy scales o...There must be electromagnetic fields created during high-energy heavy-ion collisions.Although the electromagnetic field may become weak with the evolution of the quark-gluon plasma(QGP),compared to the energy scales of the strong interaction,they are potentially important to some electromagnetic probes.In this work,we propose the coupled effect of the weak magnetic field and the longitudinal dynamics of the background medium for the first time.We demonstrate that the induced photon spectrum can be highly azimuthally anisotropic when the quarkgluon plasma is in the presence of a weak external magnetic field.On the other hand,the weak magnetic photon emission from quark-gluon plasma only leads to a small correction to the photon production rate.After hydrodynamic evolution with a tilted fireball configuration,the experimentally measured direct photon elliptic flow is well reproduced.Meanwhile,the used time-averaged magnetic field in the hydrodynamic stage is found no larger than a few percent of the pion mass square.展开更多
基金supported by National Natural Science Foundation of China
文摘Following previous study,in the littlest Higgs model(LHM),the heavy photon is supposed to be a possibledark matter candidate and its relic abundance of the heavy photon is estimated in terms of the Boltzman-Lee-Weinbergtime-evolution equation.The effect of the T-parity violation is also considered.Our calculations show that when Higgsmass M_H taken to be 300 GeV and do not considering T-parity violation,only two narrow ranges 133<M_A_H<135 GeVand 167<M_A_H<169 GeV are tolerable with the current astrophysical observation and if 135<M_A_H<167 GeV,there must at least exist another species of heavy particle contributing to the cold dark matter.As long as the T-paritycan be violated,the heavy photon can decay into regular standard model particles and would affect the dark matterabundance in the universe,we discuss the constraint on the T-parity violation parameter based on the present data.Direct detection prospects are also discussed in some detail.
文摘There must be electromagnetic fields created during high-energy heavy-ion collisions.Although the electromagnetic field may become weak with the evolution of the quark-gluon plasma(QGP),compared to the energy scales of the strong interaction,they are potentially important to some electromagnetic probes.In this work,we propose the coupled effect of the weak magnetic field and the longitudinal dynamics of the background medium for the first time.We demonstrate that the induced photon spectrum can be highly azimuthally anisotropic when the quarkgluon plasma is in the presence of a weak external magnetic field.On the other hand,the weak magnetic photon emission from quark-gluon plasma only leads to a small correction to the photon production rate.After hydrodynamic evolution with a tilted fireball configuration,the experimentally measured direct photon elliptic flow is well reproduced.Meanwhile,the used time-averaged magnetic field in the hydrodynamic stage is found no larger than a few percent of the pion mass square.
