9 research outputs found
General tree-level amplitudes by factorization limits
To find boundary contributions is a rather difficult problem when applying
the BCFW recursion relation. In this paper, we propose an approach to bypass
this problem by calculating general tree amplitudes that contain no polynomial
using factorization limits. More explicitly, we construct an expression
iteratively, which produces correct factorization limits for all physical
poles, and does not contain other poles, then it should be the correct
amplitude. To some extent, this approach can be considered as an alternative
way to find boundary contributions. To demonstrate our approach, we present
several examples: theory, pure gauge theory, Einstein-Maxwell theory,
and Yukawa theory. While the amplitude allows the existence of polynomials
which satisfy correct mass dimension and helicities, this approach is not
applicable to determine the full amplitude.Comment: 29 page
Determination of Boundary Contributions in Recursion Relation
In this paper, we propose a new algorithm to systematically determine the
missing boundary contributions, when one uses the BCFW on-shell recursion
relation to calculate tree amplitudes for general quantum field theories. After
an instruction of the algorithm, we will use several examples to demonstrate
its application, including amplitudes of color-ordered phi-4 theory, Yang-Mills
theory, Einstein-Maxwell theory and color-ordered Yukawa theory with phi-4
interaction.Comment: 20 pages, 1 appendi
Preparation of Large Volume Solid Argon Crystal and Its Feasibility Test as a Scintillation Material
An important background to the liquid argon detectors is that they are caused by the diffusion of radioactive isotopes in a scintillator (liquid phase). This radioactive isotope is produced in argon’s surrounding devices, such as circulation pipelines and liquid argon containers. The solid argon as a scintillation material in the detector can inhibit the diffusion and drift of radioactive isotopes in a solid phase scintillator. Additionally, the structure of a solid argon detector is simple and reduces the total source of radioactive background. In the CDEX-300 detection system, solid argon could substitute for liquid argon as the veto detector, preventing radioactive isotopes drifting to the central main detector (HPGe detectors array) surface to reduce backgrounds. Therefore, solid argon has great potential in the experiments since it is especially helpful to get the lower background in a larger active volume than liquid argon required in those low background detection experiments. This work introduces the preparation process and device of the large volume transparent crystalline argon, the acquisition of scintillation light, and the pulse amplitude spectrum of 137Cs obtained from a prototype detector of transparent solid argon crystal. The results show that the scheme proposed in this study can successfully produce a large volume transparent crystalline argon detector, the scintillation light signals can be effectively obtained from the solid argon scintillator, and the corresponding pulse amplitude spectrum is given. This work indicates that it is feasible to develop a solid argon crystal scintillation detector by using our approach
Preparation of Large Volume Solid Argon Crystal and Its Feasibility Test as a Scintillation Material
An important background to the liquid argon detectors is that they are caused by the diffusion of radioactive isotopes in a scintillator (liquid phase). This radioactive isotope is produced in argon’s surrounding devices, such as circulation pipelines and liquid argon containers. The solid argon as a scintillation material in the detector can inhibit the diffusion and drift of radioactive isotopes in a solid phase scintillator. Additionally, the structure of a solid argon detector is simple and reduces the total source of radioactive background. In the CDEX-300 detection system, solid argon could substitute for liquid argon as the veto detector, preventing radioactive isotopes drifting to the central main detector (HPGe detectors array) surface to reduce backgrounds. Therefore, solid argon has great potential in the experiments since it is especially helpful to get the lower background in a larger active volume than liquid argon required in those low background detection experiments. This work introduces the preparation process and device of the large volume transparent crystalline argon, the acquisition of scintillation light, and the pulse amplitude spectrum of 137Cs obtained from a prototype detector of transparent solid argon crystal. The results show that the scheme proposed in this study can successfully produce a large volume transparent crystalline argon detector, the scintillation light signals can be effectively obtained from the solid argon scintillator, and the corresponding pulse amplitude spectrum is given. This work indicates that it is feasible to develop a solid argon crystal scintillation detector by using our approach