We derive the separate helicity amplitudes using the partial wave analysis in the process of pseudo-scalar meson photoproduction.For J^P= 3/2^+,we find the amplitude is model independent.According to parity conservati...We derive the separate helicity amplitudes using the partial wave analysis in the process of pseudo-scalar meson photoproduction.For J^P= 3/2^+,we find the amplitude is model independent.According to parity conservation,the general amplitude in the case of J^P=1/2 is obtained.We prove this general amplitude corresponds to the situation of λ=-1 when adopting the circular polarization.Finally,the formulas of scattering amplitudes involving the meson photoproduction with J^P= 3/2^+ are obtained from the chiral quark model.展开更多
In light of our previous study [Chin. Phys. C 44(8), 085103(2020)], we investigate the possibility of the formation of a primordial black hole in the second inflationary process induced by the oscillation of the curva...In light of our previous study [Chin. Phys. C 44(8), 085103(2020)], we investigate the possibility of the formation of a primordial black hole in the second inflationary process induced by the oscillation of the curvaton. By adopting the instability of the Mathieu equation, one can utilize the δ function to fully describe the power spectrum.Owing to the running of the curvaton mass, we can simulate the value of the abundance of primordial black holes covering almost all of the mass ranges. Three special cases are given. One case may account for dark matter because the abundance of a primordial black hole is approximately 75%. As late times, the relic of exponential potential may be approximated to a constant of the order of a cosmological constant, which is dubbed as the role of dark energy.Thus, our model could unify dark energy and dark matter from the perspective of phenomenology. Finally, it sheds new light on exploring Higgs physics.展开更多
In this paper,we propose a homogeneous curvaton mechanism that operates during the preheating process and in which the effective mass is running(i.e.,its potential consists of a coupling term and an exponential term w...In this paper,we propose a homogeneous curvaton mechanism that operates during the preheating process and in which the effective mass is running(i.e.,its potential consists of a coupling term and an exponential term whose contribution is subdominant thereto).This mechanism can be classified into either narrow resonance or broad resonance cases,with the spectral index of the curvaton consituting the deciding criteria.The inflationary potential is that of chaotic inflation(i.e.,a quadratic potential),which could result in a smooth transition into the preheating process.The entropy perturbations are converted into curvature perturbations,which we validate using theδN formalism.By neglecting the exponential term's contribution to the curvaton potential,we calculate the power spectrum Pζand the nonlinear non-Gaussian parameter fNL.Our calculations analytically show that these two observables are independent of the inflaton potential.Finally,when the curvaton decays(and the inflaton field vanishes),the exponential potential approaches a constant value similar to that of the cosmological constant,which may play the role of dark energy.展开更多
基金Supported by the Chinese Scholarship Council(CSC)
文摘We derive the separate helicity amplitudes using the partial wave analysis in the process of pseudo-scalar meson photoproduction.For J^P= 3/2^+,we find the amplitude is model independent.According to parity conservation,the general amplitude in the case of J^P=1/2 is obtained.We prove this general amplitude corresponds to the situation of λ=-1 when adopting the circular polarization.Finally,the formulas of scattering amplitudes involving the meson photoproduction with J^P= 3/2^+ are obtained from the chiral quark model.
基金Supported by the Hunan Provincial Department of Education (19B464)the National Natural Science Foundation of China (NSFC, 12165009)。
文摘In light of our previous study [Chin. Phys. C 44(8), 085103(2020)], we investigate the possibility of the formation of a primordial black hole in the second inflationary process induced by the oscillation of the curvaton. By adopting the instability of the Mathieu equation, one can utilize the δ function to fully describe the power spectrum.Owing to the running of the curvaton mass, we can simulate the value of the abundance of primordial black holes covering almost all of the mass ranges. Three special cases are given. One case may account for dark matter because the abundance of a primordial black hole is approximately 75%. As late times, the relic of exponential potential may be approximated to a constant of the order of a cosmological constant, which is dubbed as the role of dark energy.Thus, our model could unify dark energy and dark matter from the perspective of phenomenology. Finally, it sheds new light on exploring Higgs physics.
基金LH is funded by Hunan Natural Science Foundation(2020JJ5452)Hunan Provincial Department of Education(19B464)WL is funded by NSFC(1175012)。
文摘In this paper,we propose a homogeneous curvaton mechanism that operates during the preheating process and in which the effective mass is running(i.e.,its potential consists of a coupling term and an exponential term whose contribution is subdominant thereto).This mechanism can be classified into either narrow resonance or broad resonance cases,with the spectral index of the curvaton consituting the deciding criteria.The inflationary potential is that of chaotic inflation(i.e.,a quadratic potential),which could result in a smooth transition into the preheating process.The entropy perturbations are converted into curvature perturbations,which we validate using theδN formalism.By neglecting the exponential term's contribution to the curvaton potential,we calculate the power spectrum Pζand the nonlinear non-Gaussian parameter fNL.Our calculations analytically show that these two observables are independent of the inflaton potential.Finally,when the curvaton decays(and the inflaton field vanishes),the exponential potential approaches a constant value similar to that of the cosmological constant,which may play the role of dark energy.
