학술논문
The two-photon exchange experiment at DESY
Document Type
Original Paper
Author
Alarcon, R.; Beck, R.; Bernauer, J. C.; Broering, M.; Christopher, A.; Cline, E. W.; Dhital, S.; Dongwi, B.; Fernando, I.; Finger, M.; Finger Jr., M.; Friščić, I.; Gautam, T.; Grauvogel, G. N.; Hasell, D. K.; Hen, O.; Horn, T.; Ihloff, E.; Johnston, R.; Kelsey, J.; Kohl, M.; Kutz, T.; Lavrukhin, I.; Lee, S.; Lorenzon, W.; Lunkenheimer, S.; Maas, F.; Milner, R. G.; Moran, P.; Nazeer, J.; Patel, T.; Rathnayake, M.; Raymond, R.; Redwine, R. P.; Schmidt, A.; Schneekloth, U.; Sokhan, D.; Suresh, M.; Vidal, C.; Yang, Z.
Source
The European Physical Journal A: Hadrons and Nuclei. 60(4)
Subject
Language
English
ISSN
1434-601X
Abstract
We propose a new measurement of the ratio of positron-proton to electron-proton elastic scattering at DESY. The purpose is to determine the contributions beyond single-photon exchange, which are essential for the Quantum Electrodynamic (QED) description of the most fundamental process in hadronic physics. By utilizing a 20 cm long liquid hydrogen target in conjunction with the extracted beam from the DESY synchrotron, we can achieve an average luminosity of 2.12×1035-2·-1≈200Q2=4.62 cm2.12×1035-2·-1≈200Q2=4.62s2.12×1035-2·-1≈200Q2=4.62 (2.12×1035-2·-1≈200Q2=4.62 times the luminosity achieved by OLYMPUS). The proposed two-photon exchange experiment (TPEX) entails a commissioning run at a beam energy of 2 GeV, followed by measurements at 3 GeV, thereby providing new data up to 2.12×1035-2·-1≈200Q2=4.62 (GeV/c)2.12×1035-2·-1≈200Q2=4.62 (twice the range of current measurements). We present and discuss the proposed experimental setup, run plan, and expectations.