Technical Design Report for the Paul Scherrer Institute Experiment R-12-01.1: Studying the Proton "Radius" Puzzle with $\mu p$ Elastic Scattering
Technical Design Report for the Paul Scherrer Institute Experiment R-12-01.1: Studying the Proton "Radius" Puzzle with $\mu p$ Elastic Scattering
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Paul Scherrer 研究所实验 R-12-01.1 的技术设计报告：用 $mu p$ 弹性散射研究质子“半径”谜题
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发表时间：
2017
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通讯作者：
M. Taragin
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作者：
R. Gilman;E. Downie;G. Ron;S. Strauch;A. Afanasev;A. Akmal;J. Arrington;H. Atac;C. Ayerbe;F. Benmokhtar;N. Benmouna;J. Bernauer;A. Blomberg;W. Briscoe;D. Cioffi;E. Cline;D. Cohen;E. Cohen;C. Collicott;K. Deiters;J. Diefenbach;B. Dongwi;D. Ghosal;A. Golossanov;R. Gothe;D. Higinbotham;D. Hornidge;Y. Ilieva;N. Kalantarians;M. Kohl;B. Krusche;G. Kumbartzki;I. Lavrukhin;L. Li;J. Lichtenstadt;W. Lin;A. Liyanage;W. Lorenzon;K. Mesick;Z. Meziani;P. Mohanmurthy;P. Moran;J. Nazeer;E. Piasetzsky;R. Ransome;R. Raymond;D. Reggiani;P. Reimer;A. Richter;T. Rostomyan;P. Roy;A. Sarty;Y. Shamai;N. Sparveris;N. Steinberg;I. Strakovsky;V. Sulkosky;A. Tadepalli;M. Taragin
用$\mu p$原子和$ep$原子以及散射测量的质子半径的差异仍然是一个无法解释的难题。PSI MUSE建议在同一实验中同时测量$\mu p$和$e p$散射。实验将确定两个反应的横截面，双光子效应，形状因子和半径独立，并将允许$\mu p$和$ep$的结果进行比较，减少系统的不确定性。这些数据应该是迄今为止在散射实验中对轻子普适性的最佳测试，比以前的测试提高了一个数量级。测量两种粒子极性的散射将允许在亚百分比水平上测试双光子交换，不确定性提高了四倍，数据点比以前的低动量转移测定多了一个数量级，类似于当前一代的更高动量转移电子实验。实验有可能证明$\mu p$和$ep$相互作用是一致的还是不同的，以及是否有任何差异来自新物理或双光子交换。不确定性是这样的，如果差异是真实的，它应该被确认为$\approx$5$\sigma $的意义，类似于已经建立的规则和μ子氢兰姆位移之间。
The difference in proton radii measured with $\mu p$ atoms and with $ep$ atoms and scattering remains an unexplained puzzle. The PSI MUSE proposal is to measure $\mu p$ and $e p$ scattering in the same experiment at the same time. The experiment will determine cross sections, two-photon effects, form factors, and radii independently for the two reactions, and will allow $\mu p$ and $ep$ results to be compared with reduced systematic uncertainties. These data should provide the best test of lepton universality in a scattering experiment to date, about an order of magnitude improvement over previous tests. Measuring scattering with both particle polarities will allow a test of two-photon exchange at the sub-percent level, about a factor of four improvement on uncertainties and over an order of magnitude more data points than previous low momentum transfer determinations, and similar to the current generation of higher momentum transfer electron experiments. The experiment has the potential to demonstrate whether the $\mu p$ and $ep$ interactions are consistent or different, and whether any difference results from novel physics or two-photon exchange. The uncertainties are such that if the discrepancy is real it should be confirmed with $\approx$5$\sigma$ significance, similar to that already established between the regular and muonic hydrogen Lamb shift.