非線性交換幾何電弱模型下正負電子對撞

e+e- → γγ in noncommutative electroweak model

陳建羽(Chien-Yu Chen)

指導教授 ： 耿朝強

國立清華大學/理學院/物理學系/碩士(2006年)

摘要

我們簡介一些在非線性交換電弱模型下 e+e- --> e+e-, e+e- --> e-e- 和 e+e- --> γγ 線性碰撞的過程. 我們發現Ward identity在 e+e- --> γγ 過程中不會自動被滿足. 雖然這個理論沒有UV的問題,但還是仍然會破壞么正對稱性,而為了要解決這類的問題必須限制背景電場為零,背景張量場內積大於等於零和第一階 θ 必須不存在,使得因果關係, 么正性和規範對稱被滿足.

關鍵字

弦論 ； 時空不對易 ； 非線性交換幾何 ； 非線性交換幾何場論

並列摘要

We study some tree level processes, such as e+e− → e+e−, e−e− → e−e− and e+e− → γγ in the noncommutative electroweak model. We find that the process of e+e− → γγ does not automatically satisfy the Ward identity. To solve this problem, we assume θ0i = ~E 2 NC = 0, θµνθµν > 0 and the vanishing first order θ terms. The constrains of θ0i= ~E 2 NC = 0 and θµνθµν > 0 are used to solve the causality and unitary problems, although such theories are free of ultraviolet divergence but they still violate unitarity.

並列關鍵字

string theory ； noncommutative spacetime ； noncommutative geometry ； noncommutative field theory

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