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arXiv 1503.08538hep-ph
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在高能$e^+e^-$对撞机上通过单光子过程表征不可见电弱粒子

Characterizing Invisible Electroweak Particles through Single-Photon Processes at High Energy $e^+e^-$ Colliders

Seong Youl Choi, Tao Han, Jan Kalinowski, Krzysztof Rolbiecki, Xing Wang

摘要:

我们探讨的情况下,在电弱尺度上唯一可访问的新的状态包括一对色单态电弱粒子,其质量是简并在树水平和分裂只有电弱对称性破缺在循环水平。为了便于说明,我们考虑了一个超对称模型,并研究了以下三种具有代表性的情况:(a)两个自旋为1/2的Higgsino SU(2)$_L$双峰,(b)一个自旋为1/2的wino SU(2)$_L$三重态和(c)一个自旋为0的左手slepton SU(2)$_L$双峰。由于质量简并,这些较低的电弱态在LHC上很难观察到,在$e^+ e^-$对撞机上也很难检测到。利用高能$e^+ e^-$碰撞中硬光子辐射产生的电子对。如果在运动学上可以实现的话,那么在$e^+e^-$对撞机上用偏振光束进行的这种单光子过程使我们能够通过测量相关硬光子的能量和散射角来表征每种情况,并通过光子能量分布中的阈值行为来明确地确定几乎不可见的粒子的自旋。

英文摘要:

We explore the scenarios where the only accessible new states at the electroweak scale consist of a pair of color-singlet electroweak particles, whose masses are degenerate at the tree level and split only by electroweak symmetry breaking at the loop level. For the sake of illustration, we consider a supersymmetric model and study the following three representative cases with the lower-lying states as (a) two spin-1/2 Higgsino SU(2)$_L$ doublets, (b) a spin-1/2 wino SU(2)$_L$ triplet and (c) a spin-0 left-handed slepton SU(2)$_L$ doublet. Due to the mass-degeneracy, those lower-lying electroweak states are difficult to observe at the LHC and rather challenging to detect at the $e^+ e^-$ collider as well. We exploit the pair production in association with a hard photon radiation in high energy $e^+ e^-$ collisions. If kinematically accessible, such single-photon processes at $e^+e^-$ colliders with polarized beams enable us to characterize each scenario by measuring the energy and scattering angle of the associated hard photon, and to determine the spin of the nearly invisible particles unambiguously through the threshold behavior in the photon energy distribution.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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