The valence changes of doped samarium and the creation as well as the annihilation of F-centers in the processes of thermostimulated luminescence (TSL) and photostimulated luminescence (PSL) of BaFCl∶Sm crystal have ...The valence changes of doped samarium and the creation as well as the annihilation of F-centers in the processes of thermostimulated luminescence (TSL) and photostimulated luminescence (PSL) of BaFCl∶Sm crystal have been studied. As being irradiated by X-ray,a large number of electron-hole pairs are created in the crystal.Most of the electrons may be trapped at the anion vacancies,producing F-centers.The doped samarium ions,which existed mostly in trivalent state (Sm^(3+)),may capture the holes and convert themselves to tetravalent state.So that part of the incident X-ray energy are stored in this nonequilibrium system.On optical and thermal stimulation the stored energy can be liberated as a characteristic emission of trivalent samarium ion.This emission originates from the recombination of the F-center electrons with tetravalent samarium ions,i.e.the F-center electrons may be excited to the conduction band by optical or thermal stirnulation and then recombine with tetravalent samarium ions.This recombination makes the samarium ions to be in situ reduced to the excited state of Sm^(3+),and gives rise to the characteristic emission of Sm^(3+). On the other hand,during X-irradiation a few electrons can be trapped at the sites of trivalent samarium ions and reduce them to divalent state.But the formation of divalent samarium On X-irradiation is very small as compared with that of F-centers and so their influence on the PSL and TSL can be neglected.展开更多
Accessing a full image of the inner content of hadrons represents a central endeavour of modern particle physics,with the main scientific motivation to investigate the strong interaction binding the visible matter.On ...Accessing a full image of the inner content of hadrons represents a central endeavour of modern particle physics,with the main scientific motivation to investigate the strong interaction binding the visible matter.On the one hand,the structure of known exotic candidates is a fundamental open issue addressed widely by scientists.On the other hand,looking for new states of exotic nature is a central component for theoretical and experimental efforts from electron-positron machine and electron accelerator with fixed target to heavy ion and electron-ion colliders.In this article we present a succinct short overview of the attempt to search for exotic narrow N∗and Z states containing light quarks only or also charm,and its connotation for bottom regions(the latter two are also known as Pc(Zc)and Pb(Zb)states,respectively in the literature).We address the effort of searching for exotic narrow N∗and Z states in light quark sector.We focus on recent progress in searching for signal of Pc and Zc states photoproduction and its implication into the Pb and Zb photoproduction and their decay properties.We also discuss future perspectives for the field in electron-ion colliders,a good place to disentangle the nature of some of these states and investigate some other enlightening topics including QCD trace anomaly and quarkonium-nucleon scattering length.展开更多
文摘The valence changes of doped samarium and the creation as well as the annihilation of F-centers in the processes of thermostimulated luminescence (TSL) and photostimulated luminescence (PSL) of BaFCl∶Sm crystal have been studied. As being irradiated by X-ray,a large number of electron-hole pairs are created in the crystal.Most of the electrons may be trapped at the anion vacancies,producing F-centers.The doped samarium ions,which existed mostly in trivalent state (Sm^(3+)),may capture the holes and convert themselves to tetravalent state.So that part of the incident X-ray energy are stored in this nonequilibrium system.On optical and thermal stimulation the stored energy can be liberated as a characteristic emission of trivalent samarium ion.This emission originates from the recombination of the F-center electrons with tetravalent samarium ions,i.e.the F-center electrons may be excited to the conduction band by optical or thermal stirnulation and then recombine with tetravalent samarium ions.This recombination makes the samarium ions to be in situ reduced to the excited state of Sm^(3+),and gives rise to the characteristic emission of Sm^(3+). On the other hand,during X-irradiation a few electrons can be trapped at the sites of trivalent samarium ions and reduce them to divalent state.But the formation of divalent samarium On X-irradiation is very small as compared with that of F-centers and so their influence on the PSL and TSL can be neglected.
文摘Accessing a full image of the inner content of hadrons represents a central endeavour of modern particle physics,with the main scientific motivation to investigate the strong interaction binding the visible matter.On the one hand,the structure of known exotic candidates is a fundamental open issue addressed widely by scientists.On the other hand,looking for new states of exotic nature is a central component for theoretical and experimental efforts from electron-positron machine and electron accelerator with fixed target to heavy ion and electron-ion colliders.In this article we present a succinct short overview of the attempt to search for exotic narrow N∗and Z states containing light quarks only or also charm,and its connotation for bottom regions(the latter two are also known as Pc(Zc)and Pb(Zb)states,respectively in the literature).We address the effort of searching for exotic narrow N∗and Z states in light quark sector.We focus on recent progress in searching for signal of Pc and Zc states photoproduction and its implication into the Pb and Zb photoproduction and their decay properties.We also discuss future perspectives for the field in electron-ion colliders,a good place to disentangle the nature of some of these states and investigate some other enlightening topics including QCD trace anomaly and quarkonium-nucleon scattering length.
