Doctorate 2001, Diploma 1996,
Technical University Darmstadt, Germany
Experimental Nuclear Physics, Nucleon and Few-Body Structure, Fundamental Symmetries
I am an experimental nuclear physicist with a joint position both as faculty at HU and as staff scientist at the Thomas Jefferson National Accelerator Facility (Jefferson Lab) located not far from the HU campus. My research interests are to explore the internal structure of protons, neutrons and light nuclei with the help of electron scattering and by utilizing spin degrees of freedom, which I have pursued at several laboratories – the Mainz Microtron (MAMI) at University of Mainz, Germany, the S-DALINAC at the Technical University of Darmstadt, Germany, the MIT-Bates Linear Accelerator Center in Middleton, Massachusetts, and now at Jefferson Lab in Virginia. The electron scattering process is usually described in the framework of one-photon exchange, which allows using this method to explore strongly interacting matter such as nucleons and nuclei and their internal structure generated by quarks and gluons. The unprecedented precision of spin-dependent electron scattering has recently led to the question to what extent the exchange of two or more photons in the scattering process influences the observations. I have been co-initiator of a definitive experiment to resolve this question (OLYMPUS), which has been carried out at DESY in Hamburg, Germany, a large facility providing intense electron (and positron) beams. OLYMPUS is designed to very precisely compare elastic scattering of electrons with that of positrons in a storage ring from an internal proton target. I am co-initiator of the Muon Scattering Experiment (MUSE) at the Paul-Scherrer Institute (PSI) in Switzerland, which aims to investigate the so-called proton radius puzzle and the controversial question why recent measurements of the proton size with electrons and muons give differing results.
Another major research area of mine is the search for New Physics beyond the Standard Model. The observed excess of matter over antimatter in the universe cannot be explained with the current Standard Model, which on the other hand does account for all symmetry violations observed so far. According to A. Sakharov’s criteria, discovery of new sources of symmetry violations (such as charge-parity or time reversal) are required for our understanding of the cosmos. I have co-initiated the Time Reversal Experiment with Kaons (TREK) proposed at J-PARC in Japan, which aims to find such new sources in the decay of charged kaons produced at J-PARC. A first measurement with TREK/E36 carried out in 2015 aims at a precision test of the ratio of electron and muon couplings, which are identical (universal) in the Standard Model. TREK/E36 also allows to search for light new particles such as dark photons, proposed theoretically designed to explain some observed amomalies.
Moreover, I am a principal investigator of the DarkLight experiment in preparation at the Low-Energy Recirculator Facility (LERF) at Jefferson Lab, a dedicated search for dark photons with light masses. Lastly, I am a co-spokesperson of the C-GEN experiment proposed in Hall C at Jefferson Lab to measure the neutron electric form factor at large momentum transfer with polarization transfer in deuteron electrodisintegration.
For the above experiments my group has been constructing and operating charged-particle tracking detectors based on Gas Electron Multiplier (GEM) technology, a novel technique originally developed at CERN in Switzerland. GEM-detectors are relatively inexpensive, less fragile than wire chambers, and can be run at very high particle rates in very harsh radiation environments.
- R. Milner et al., The OLYMPUS Experiment, Nucl. Instrum. and Meth. A741, 1-17 (2014).
- M. Kohl (for the MUSE Collaboration), The Muon Scattering Experiment (MUSE) at PSI and the proton radius puzzle, Proc. 13th International Workshop on Production, Properties and Interaction of Mesons (MESON2014), Cracow, Poland, May 29 – June 3, 2014, EPJ Web Conf. 81 (2014) 02008, DOI: 10.1051/epjconf/20148102008.
- M. Kohl (for the TREK collaboration), The TREK/E36 Experiment at J-PARC, Proc. Int. Workshop to Explore Physics Opportunities with Intense, Polarized Electron Beams up to 300 MeV (PEB2013), MIT, Cambridge, MA, March 14-16, 2013, AIP Conf. Proc. 1563, 147 (2013).
- C. Zhang et al., Precise Measurement of Deuteron Tensor Analyzing Powers with BLAST, Phys. Rev. Lett. 107, 0252501 (2011).
- D.K. Hasell, R.G. Milner, Robert P. Redwine, R. Alarcon, H. Gao, M. Kohl, and J.R. Calarco, Spin-Dependent Electron Scattering from Polarized Protons and Deuterons with the BLAST Experiment at MIT-Bates, Annu. Rev. Nucl. Part. Sci. 61, 409 (2011).
- D. Hasell, T. Akdogan, R. Alarcon, W. Bertozzi, E. Booth, T. Botto, J.R. Calarco, B. Clasie, C. Crawford, A. DeGrush, K. Dow, D. Dutta, M. Farkhondeh, R. Fatemi, O. Filoti, W. Franklin, H. Gao, E. Geis, S. Gilad, W. Hersman, M. Holtrop, E. Ihloff, P. Karpius, J. Kelsey, M. Kohl, H. Kolster, S. Krause, T. Lee, A. Maschinot, J. Matthews, K. McIlhany, N. Meitanis, R. Milner, J. Rapaport, R. Redwine, J. Seely, A. Shinozaki, A. Sindile, S. Širca, T. Smith, S. Sobczynski, M. Tanguay, B. Tonguc, C. Tschalaer, E. Tsentalovich, W. Turchinetz, J.F.J. van den Brand, J. van der Laan, F. Wang, T. Wise, Y. Xiao, W. Xu, C. Zhang, Z. Zhou, V. Ziskin, and T. Zwart, The BLAST Experiment, Nucl. Instrum. and Meth. A. 603, 247 (2009).
- F. Simon, J. Kelsey, M. Kohl, R. Majka, M. Pleska, T. Sakuma, N. Smirnow, H. Spinka, B. Surrow, and D. Underwood,Beam Performance of Tracking Detectors with Industrially Produced GEM Foils, Nucl. Instrum. and Meth. A 598, 432 (2009).
- M. Kohl, The OLYMPUS Experiment at DESY, Proc. Int. Workshop on Positrons at Jefferson Lab (JPOS09), AIP Conf. Proc. 1160, 19 (2009).
- M. Kohl, Nucleon Form Factors from BLAST, Proc. 8th Int. Spin Physics Symposium, AIP Conf. Proc. 1149, 585 (2009).
- M. Kohl, The Time Reversal Experiment with Kaons (TREK) at J-PARC, Proc. 8th Int. Spin Physics Symposium, AIP Conf. Proc. 1149, 233 (2009).
- E. Geis, M. Kohl, V. Ziskin, T. Akdogan , H. Arenhövel, R. Alarcon, W. Bertozzi, E. Booth, T. Botto, J. Calarco, B. Clasie, C.B. Crawford, A. DeGrush, T.W. Donnelly, K. Dow, M. Farkhondeh, R. Fatemi, O. Filoti, W. Franklin, H. Gao, S. Gilad, D. Hasell, P. Karpius, H. Kolster, T. Lee, A. Maschinot, J. Matthews, K. McIlhany, N. Meitanis, R.G. Milner, J. Rapaport, R.P. Redwine, J. Seely, A. Shinozaki, S.Širca, A. Sindile E. Six, T. Smith, M. Steadman, B. Tonguc, C. Tschalaer, E. Tsentalovich, W. Turchinetz, Y. Xiao, W. Xu, C. Zhang, Z. Zhou, and T. Zwart,The Charge Form Factor of the Neutron at Low Momentum Transfer from the 2H(e,e'n)p Reaction, Phys. Rev. Lett. 101, 042501 (2008).
- M. Kohl, Elastic Form Factors of the Proton, Neutron and Deuteron, Proc. Int. Nuclear Physics Conference, Tokyo, Japan, June 3-8, 2007, Nucl. Phys. A805, 361c (2008).
- C.B. Crawford, A. Sindile, T. Akdogan, R. Alarcon, W. Bertozzi, E. Booth, T. Botto, J. Calarco, B. Clasie, A. DeGrush, T.W. Donnelly, K. Dow, D. Dutta, M. Farkhondeh, R. Fatemi, O. Filoti, W. Franklin, H. Gao, E. Geis, S. Gilad, W. Haeberli, D. Hasell, W. Hersman, M. Holtrop, P. Karpius, M. Kohl, H. Kolster, T. Lee, A. Maschinot, J. Matthews, K. McIlhany, N. Meitanis, R.G. Milner, J. Rapaport, R.P. Redwine, J. Seely, A. Shinozaki, S. Sirca, E. Six, T. Smith, B. Tonguc, C. Tschalaer, E. Tsentalovich, W. Turchinetz, J.F.J. van den Brand, J. van der Laan, F. Wang, T. Wise, Y. Xiao, W. Xu, C. Zhang, Z. Zhou, V. Ziskin, and T. Zwart,Measurement of the Proton Electric to Magnetic Form Factor Ratio from H(e,e’p), Phys. Rev. Lett. 98, 052301 (2007).
- M. Kohl, M. Ases Antelo, C. Ayerbe, D. Baumann, R. Böhm, D. Bosnar, M. Ding, M.O. Distler, J. Friedrich, J. García Llongo, P. Jennewein, G. Jover Manas, H. Merkel, P. Merle, U. Müller, R. Neuhausen, L. Nungesser, R. Pérez Benito, J. Pochodzalla, M. Potokar, C. Rangacharyulu, A. Richter, G. Schrieder, M. Seimetz, Th. Walcher, and M. Weis,
Search for Narrow Nucleon Resonances below Pion Threshold in the 1H(e,e’pi+)X and 2H(e,e’p)X Reactions,Phys. Rev. C 67,065204 (2003).
- M. Kohl, P. Bartsch, D. Baumann, J. Bermuth, R. Böhm, K. Bohinc, S. Derber, M. Ding, M.O. Distler, I. Ewald, J. Friedrich, J.M. Friedrich, P. Jennewein, M. Kahrau, S.S. Kamalov, A. Kozlov, K.W. Krygier, M. Kuss, A. Liesenfeld, H. Merkel, P. Merle, U. Müller, R. Neuhausen, Th. Pospischil, M. Potokar, C. Rangacharyulu, A. Richter, D. Rohe, G. Rosner, H. Schmieden, G. Schrieder, M. Seimetz, S. Širca, T. Suda, L. Tiator, M. Urban, A. Wagner, Th. Walcher, J. Wambach, M. Weis, and A. Wirzba, Self Energies of the Pion and the D Isobar from the 3He(e,e’p+)3H Reaction, Phys. Lett. B530, 67 (2002).
- Co-initiator and International Spokesperson of the Time Reversal Experiment with Kaons (TREK) at J-PARC, Japan
- Co-initiator of the Muon Scattering Experiment (MUSE) at PSI, Switzerland
- Principal Investigator of the DarkLight experiment and co-spokesperson of the C-GEN (E12-11-009) experiment at Jefferson Lab
- Co-initiator and former spokesman of the OLYMPUS experiment at DESY, Hamburg, Germany
- Principal Investigator of U.S. federal grants exceeding $2.7 Million
- TREK collaboration (http://trek.kek.jp)
- MUSE collaboration (http://www.physics.rutgers.edu/~gilman/elasticmup/)
- OLYMPUS collaboration (http://web.mit.edu/OLYMPUS/)
- DarkLight Collaboration (Jlab) (http://dmtpc.mit.edu/DarkLight/)
- E12-11-009/C-GEN Collaboration (Jlab) (http://wiki.jlab.org/E12-11-009/)
- E07-003 (SANE) collaboration (JLab) (http://www.jlab.org/~rondon/sane/)
- E04-108/019 collaboration (JLab) (http://hallcweb.jlab.org/experiments/GEp-III/)
- EIC/eRHIC collaboration (http://www.bnl.gov/eic)
- BLAST collaboration (http://blast.lns.mit.edu)
- MAMI A1 collaboration (http://wwwa1.kph.uni-mainz.de)