SFB 1044:  The Low-Energy Frontier of the Standard Model: From Quarks and Gluons to Hadrons and Nuclei

• Subject Area: Physics
• Term: from 2012 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 204404729

• Final Report Year: 2021

Final Report Abstract

The CRC 1044 studied the role of hadrons, which are subatomic particles built up from quarks and gluons, within the broader context of particle, atomic, and nuclear (astro-)physics. Hadron physics plays a central and connecting role in answering physics questions at both the highest and lowest energy scales. In nearly all questions at the forefront of the aforementioned research fields, the progress is limited by a missing quantitative knowledge of the strong interaction in the non-perturbative domain of Quantum Chromo Dynamics (QCD). Advancing this low-energy frontier of the Standard Model (SM) of particle physics has a direct impact on the most central questions in physics. In the CRC 1044, these research goals were pursued by a strategic cooperation between the Mainz Microtron (MAMI), the Beijing Spectrometer (BESIII), and the Mainz Energy Recovering Superconducting Accelerator MESA, which is presently being constructed as a main initiative within the PRISMA/PRISMA+ Excellence Cluster. Through a unique combination of measurements in electron scattering (MAMI and MESA), in electron-positron physics (BESIII), with state-of-the-art theoretical tools, such as lattice QCD, dispersion theory, and effective field theory, the CRC 1044 contributed to decisive advances in the low-energy frontier of the SM. The highlights of the CRC 1044 are firstly a new measurement at BESIII of the time-like pion form factor, reducing the dominant uncertainty, due to the hadronic vacuum polarization (HVP) contribution, in the SM prediction of the anomalous magnetic moment of the muon (g − 2)µ. The data-driven dispersive HVP determination has been complemented within the CRC 1044 with ab-initio lattice QCD calculations. An improvement of the SM prediction of (g − 2)µ is of utmost importance for a final interpretation of the experimental determination of (g − 2)µ, as obtained at Fermilab/USA and in the future at JPARC/Japan. Within the CRC 1044 the conceptual design of the parity violation experiment (P2) was completed at the MESA accelerator. In the next few years, this will make it possible to achieve the most precise measurement in the world of the weak mixing angle in electron-proton scattering and to test the SM to energy scales of around 50 TeV. A new measurement campaign of proton form factors and polarizabilities was performed at MAMI. This was complemented by refined theoretical analyses, which made it possible to significantly improve on the interpretation of high-precision tests of the Lamb shift in muonic Hydrogen as well as light muonic atoms. The activities were complemented by a new measurement of the time-like neutron form factor at BESIII. A photon-photon physics program at BESIII and A2/MAMI, aimed at extracting meson transition form factors, made it possible to derive more precise constraints on the hadronic light-by-light contribution (HLbL) to (g − 2)µ . These data were compared with a newly developed dispersive formalism, as well as a direct lattice calculation of the HLbL contribution. Furthermore, studies of spectroscopy with a polarized photon beam and polarized targets at A2/MAMI were successfully completed. The unique data sets for the photoproduction of pseudoscalar mesons on nucleons have allowed to clarify the role of several of the higher-lying resonances in the baryon spectrum. At BESIII the spectroscopy in the energy range at around 4 GeV has led to important observations of charmonium-like particles. High-precision measurements of the 4 He monopole transition form factor have been performed at A1/MAMI. A comparison with ab-initio chiral effective field theory calculations provided an important test of our understanding of few-body nuclear forces. Finally, an extended measurement campaign of beam-normal spin asymmetries in medium-heavy nuclei has been performed at MAMI, and has set the stage for the forthcoming parity-violation program at MESA, which will allow the nuclear equation of state to be studied.

Publications

• Light-by-light scattering sum rules constraining meson transition form factors. Phys. Rev. D 85 (2012) 116001
  Pascalutsa, Vladimir; Pauk, Vladyslav & Vanderhaeghen, Marc
  
• Anomalous magnetic moment of the muon in a dispersive approach. Phys. Rev. D 90 (2014) 113012
  Pauk, Vladyslav & Vanderhaeghen, Marc
  
• New determination of the η transition form factor in the Dalitz decay η → e+ e− γ with the Crystal Ball/TAPS detectors at the Mainz Microtron. Phys. Rev. C 89 no.4 (2014) 044608
  Aguar-Bartolomé, P.; Annand, J. R. M.; Arends, H. J.; Bantawa, K.; Beck, R.; Bekrenev, V.; Berghäuser, H.; Braghieri, A.; Briscoe, W. J.; Brudvik, J.; Cherepnya, S.; Codling, R. F. B.; Collicott, C.; Costanza, S.; Denig, A.; Downie, E. J.; Drexler, P.; Fil'kov, L. V.; Fix, A.; ... & Zehr, F.
  
• The electric and magnetic form factors of the proton. Phys. Rev. C 90 (2014) 015206
  Bernauer, J. C.; Distler, M. O.; Friedrich, J.; Walcher, Th.; Achenbach, P.; Ayerbe Gayoso, C.; Böhm, R.; Bosnar, D.; Debenjak, L.; Doria, L.; Esser, A.; Fonvieille, H.; Gómez Rodríguez de la Paz, M.; Friedrich, J. M.; Makek, M.; Merkel, H.; Middleton, D. G.; Müller, U.; Nungesser, L.; ... & Weinriefer, M.
  
• Observation of 4Λ H Hyperhydrogen by Decay-Pion Spectroscopy in Electron Scattering. Phys. Rev. Lett., 114 (2015) 232501
  Esser, A.; Nagao, S.; Schulz, F.; Achenbach, P.; Ayerbe Gayoso, C.; Böhm, R.; Borodina, O.; Bosnar, D.; Bozkurt, V.; Debenjak, L.; Distler, M. O.; Friščić, I.; Fujii, Y.; Gogami, T.; Hashimoto, O.; Hirose, S.; Kanda, H.; Kaneta, M.; Kim, E.; ... & Yoshida, K.
  
• Subtracted dispersion relation formalism for the two-photon exchange correction to elastic electron-proton scattering: Comparison with data. Eur. Phys. J. A 51 (2015) 2, 24
  Tomalak, O. & Vanderhaeghen, M.
  
• Lattice calculation of the pion transition form factor π 0 → γ ∗ γ ∗. Phys. Rev. D 94, no.7 (2016) 074507
  Gérardin, Antoine; Meyer, Harvey B. & Nyffeler, Andreas
  
• Measurement of the e+ e− → π + π − cross section between 600 and 900 MeV using initial state radiation. Phys. Lett. B 753 (2016) 629
  Ablikim, M.; Achasov, M.N.; Ai, X.C.; Albayrak, O.; Albrecht, M.; Ambrose, D.J.; Amoroso, A.; An, F.F.; An, Q.; Bai, J.Z.; Baldini Ferroli, R.; Ban, Y.; Bennett, D.W.; Bennett, J.V.; Bertani, M.; Bettoni, D.; Bian, J.M.; Bianchi, F.; Boger, E.; ... & Zou, J.H.
  
• Nucleon Polarizabilities: from Compton Scattering to Hydrogen Atom. Prog. Part. Nucl. Phys. 88 (2016) 29
  Hagelstein, Franziska; Miskimen, Rory & Pascalutsa, Vladimir
  
• Dark Photon Search in the Mass Range Between 1.5 and 3.4 GeV/c2. Phys. Lett. B 774 (2017) 252
  Ablikim, M.; Achasov, M.N.; Ai, X.C.; Albayrak, O.; Albrecht, M.; Ambrose, D.J.; Amoroso, A.; An, F.F.; An, Q.; Bai, J.Z.; Baldini Ferroli, R.; Ban, Y.; Bennett, D.W.; Bennett, J.V.; Bertani, M.; Bettoni, D.; Bian, J.M.; Bianchi, F.; Boger, E.; ... & Zou, J.H.
  
• Determination of the scalar polarizabilities of the proton using beam asymmetry Σ3 in Compton scattering. Eur. Phys. J. A 53 (2017) 14
  Sokhoyan, V.; Downie, E. J.; Mornacchi, E.; McGovern, J. A.; Krupina, N.; Afzal, F.; Ahrens, J.; Akondi, C. S.; Annand, J. R. M.; Arends, H. J.; Beck, R.; Braghieri, A.; Briscoe, W. J.; Cividini, F.; Collicott, C.; Costanza, S.; Denig, A.; Dieterle, M.; Ferretti, M.; ... & Zana, L.
  
• First measurement of the polarization observable E and helicity-dependent cross sections in single π 0 photoproduction from quasi-free nucleons. Phys. Lett. B 770 (2017) 523
  Dieterle, M.; Witthauer, L.; Cividini, F.; Abt, S.; Achenbach, P.; Adlarson, P.; Afzal, F.; Ahmed, Z.; Akondi, C.S.; Annand, J.R.M.; Arends, H.J.; Bashkanov, M.; Beck, R.; Biroth, M.; Borisov, N.S.; Braghieri, A.; Briscoe, W.J.; Costanza, S.; Collicott, C.; ... & Zana, L.
  
• Measurement of the ω → π 0 e+ e− and η → e+ e− γ Dalitz decays with the A2 setup at MAMI. Phys. Rev. C 95 (2017) 035208
  Adlarson, P.; Afzal, F.; Aguar-Bartolomé, P.; Ahmed, Z.; Annand, J. R. M.; Arends, H. J.; Bantawa, K.; Beck, R.; Berghäuser, H.; Biroth, M.; Borisov, N. S.; Braghieri, A.; Briscoe, W. J.; Cherepnya, S.; Cividini, F.; Collicott, C.; Costanza, S.; Danilkin, I. V.; Denig, A.; ... & Zana, L. A.
  
• New Measurements of the Beam Normal Spin Asymmetries at Large Backward Angles with Hydrogen and Deuterium Targets. Phys. Rev. Lett. 119 (2017) 012501
  Ríos, D. Balaguer; Aulenbacher, K.; Baunack, S.; Diefenbach, J.; Gläser, B.; von Harrach, D.; Imai, Y.; Kabuß, E.-M.; Kothe, R.; Lee, J. H.; Merkel, H.; Mora Espí, M. C.; Müller, U.; Schilling, E.; Weinrich, C.; Capozza, L.; Maas, F. E.; Arvieux, J.; El-Yakoubi, M. A.; ... & Prok, Y.
  
• Precise measurement of the e+ e− → π + π − J/ψ cross section at center-of-mass energies from 3.77 to 4.60 GeV. Phys. Rev. Lett. 118, no.9 (2017) 092001
  Ablikim, M.; Achasov, M. N.; Ahmed, S.; Ai, X. C.; Albayrak, O.; Albrecht, M.; Ambrose, D. J.; Amoroso, A.; An, F. F.; An, Q.; Bai, J. Z.; Bakina, O.; Baldini Ferroli, R.; Ban, Y.; Bennett, D. W.; Bennett, J. V.; Berger, N.; Bertani, M.; Bettoni, D.; ... & Zou, J. H.
  
• Study of η and η’ Photoproduction at MAMI. Phys. Rev. Lett. 118, no.21 (2017) 212001
  Kashevarov, V. L.; Ott, P.; Prakhov, S.; Adlarson, P.; Afzal, F.; Ahmed, Z.; Akondi, C. S.; Annand, J. R. M.; Arends, H. J.; Beck, R.; Braghieri, A.; Briscoe, W. J.; Cividini, F.; Codling, R.; Collicott, C.; Costanza, S.; Denig, A.; Downie, E. J.; Dieterle, M.; ... & Zana, L.
  
• The hadronic vacuum polarization contribution to the muon g − 2 from lattice QCD. JHEP 1710 (2017) 020
  Morte, M. Della; Francis, A.; Gülpers, V.; Herdoíza, G.; von Hippel, G.; Horch, H.; Jäger, B.; Meyer, H.B.; Nyffeler, A. & Wittig, H.
  
• Two-photon exchange correction to 2S − 2P splitting in muonic 3 He ions. Phys. Rev. A 95, no. 1 (2017) 012506
  Carlson, Carl E.; Gorchtein, Mikhail & Vanderhaeghen, Marc
  
• η-η mixing in large-Nc chiral perturbation theory. Phys. Rev. D 95 (2017) 054023
  Bickert, P.; Masjuan, P. & Scherer, S.
  
• Ab initio calculation of nuclear structure corrections in muonic atoms. J. Phys. G 45 (2018) 093002
  Ji, C.; Bacca, S.; Barnea, N.; Hernandez, O. J. & Nevo Dinur, N.
  
• Dispersion Theory in Electromagnetic Interactions. Ann. Rev. Nucl. Part. Sci. 68 (2018) 75-103
  Pasquini, Barbara & Vanderhaeghen, Marc
  
• Dissecting the hadronic contributions to (g − 2)µ by Schwinger’s sum rule. Phys. Rev. Lett. 120 (2018) 072002
  Hagelstein, Franziska & Pascalutsa, Vladimir
  
• Efficiency and timing performance of the MuPix7 high-voltage monolithic active pixel sensor. Nucl. Instrum. Meth. A 902 (2018) 158
  Augustin, Heiko; Berger, Niklaus; Dittmeier, Sebastian; Grzesik, Carsten; Hammerich, Jan; Hartenstein, Ulrich; Huang, Qinhua; Huth, Lennart; Immig, David Maximilian; Kiehn, Moritz; Kozlinskiy, Alexandr; Meier Aeschbacher, Frank; Meneses González, Annie; Perić, Ivan; Perrevoort, Ann-Kathrin; Schöning, André; Shrestha, Shruti; vom Bruch, Dorothea; Wauters, Frederik; ... & Wiedner, Dirk
  
• Eta and Etaprime Photoproduction on the Nucleon with the Isobar Model EtaMAID2018. Eur. Phys. J. A 54, no.12 (2018) 210
  Tiator, L.; Gorchtein, M.; Kashevarov, V. L.; Nikonov, K.; Ostrick, M.; Hadžimehmedović, M.; Omerović, R.; Osmanović, H.; Stahov, J. & Švarc, A.
  
• Experimental study of the γp → π 0 ηp reaction with the A2 setup at the Mainz Microtron. Phys. Rev. C 97, no.5 (2018) 055212
  Sokhoyan, V.; Prakhov, S.; Fix, A.; Abt, S.; Achenbach, P.; Adlarson, P.; Afzal, F.; Aguar-Bartolomé, P.; Ahmed, Z.; Ahrens, J.; Annand, J. R. M.; Arends, H. J.; Bantawa, K.; Bashkanov, M.; Beck, R.; Biroth, M.; Borisov, N. S.; Braghieri, A.; Briscoe, W. J.; ... & Zana, L. A.
  
• First measurement of the Q2 dependence of the beam-normal single spin asymmetry for elastic scattering off Carbon. Phys. Rev. Lett., 121 (2018) 022503
  Esser, A.; Thiel, M.; Achenbach, P.; Aulenbacher, K.; Baunack, S.; Beričič, J.; Bosnar, D.; Correa, L.; Dehn, M.; Distler, M. O.; Fonvieille, H.; Friščić, I.; Gorchtein, M.; Heidrich, S.; Herrmann, P.; Hoek, M.; Kegel, S.; Kohl, Y.; Kolar, T.; ... & Sfienti, C.
  
• Measurement of the decay η → π 0 π 0 η at MAMI. Phys. Rev. D 98 (2018) 012001
  Adlarson, P.; Afzal, F.; Ahmed, Z.; Akondi, C. S.; Annand, J. R. M.; Arends, H. J.; Beck, R.; Borisov, N.; Braghieri, A.; Briscoe, W. J.; Cividini, F.; Collicott, C.; Costanza, S.; Denig, A.; Downie, E. J.; Dieterle, M.; Ferretti Bondy, M. I.; Gardner, S.; Garni, S.; ... & Zana, L. A.
  
• Precision electron beam polarimetry for next generation nuclear physics experiments. Int. J. Mod. Phys. E 27 (2018) 1830004
  Aulenbacher, Kurt; Chudakov, Eugene; Gaskell, David; Grames, Joseph & Paschke, Kent D.
  
• Precision Study of η → γπ + π − Decay Dynamics. Phys. Rev. Lett. 120 (2018) 242003
  Ablikim, M.; Achasov, M. N.; Ahmed, S.; Ai, X. C.; Albayrak, O.; Albrecht, M.; Ambrose, D. J.; Amoroso, A.; An, F. F.; An, Q.; Bai, J. Z.; Ferroli, R. Baldini; Ban, Y.; Bennett, D. W.; Bennett, J. V.; Berger, N.; Bertani, M.; Bettoni, D.; Bian, J. M.; ... & Zou, J. H.
  
• The P2 Experiment - A future high-precision measurement of the weak mixing angle at low momentum transfer. Eur. Phys. J. A 54 (2018) 208
  Becker, Dominik; Bucoveanu, Razvan; Grzesik, Carsten; Imai, Kathrin; Kempf, Ruth; Molitor, Matthias; Tyukin, Alexey; Zimmermann, Marco; Armstrong, David; Aulenbacher, Kurt; Baunack, Sebastian; Beminiwattha, Rakitha; Berger, Niklaus; Bernhard, Peter; Brogna, Andrea; Capozza, Luigi; Covrig Dusa, Silviu; Deconinck, Wouter; Diefenbach, Jürgen; ... & Weitzel, Quirin
  
• Deuteron photodisintegration by polarized photons in the region of the d∗ (2380). Phys. Lett. B 789 (2019) 7
  Bashkanov, M.; Kay, S.; Watts, D.P.; Mullen, C.; Abt, S.; Achenbach, P.; Adlarson, P.; Afzal, F.; Ahmed, Z.; Akondi, C.S.; Annand, J.R.M.; Arends, H.J.; Beck, R.; Biroth, M.; Borisov, N.; Braghieri, A.; Briscoe, W.J.; Cividini, F.; Collicott, C.; ... & Zana, L.A.
  
• Neutron skins of atomic nuclei: per aspera ad astra. J. Phys. G 46, no.9 (2019) 093003
  Thiel, M.; Sfienti, C.; Piekarewicz, J.; Horowitz, C. J. & Vanderhaeghen, M.
  
• Second-order leptonic radiative corrections for lepton-proton scattering. Eur. Phys. J. A 55 (2019) 57
  Bucoveanu, R. -D. & Spiesberger, H.
  
• The hadronic light-by-light contribution to the muon’s anomalous magnetic moment. Prog. Part. Nucl. Phys. 107 (2019) 20 - 68
  Danilkin, Igor; Redmer, Christoph Florian & Vanderhaeghen, Marc
  
• The leading hadronic contribution to (g − 2)µ from lattice QCD with Nf = 2 + 1 flavours of O(a) improved Wilson quarks. Phys. Rev. D 100, no.1 (2019) 014510
  Gérardin, Antoine; Cè, Marco; von Hippel, Georg; Hörz, Ben; Meyer, Harvey B.; Mohler, Daniel; Ottnad, Konstantin; Wilhelm, Jonas & Wittig, Hartmut
  
• Extracting the spin polarizabilities of the proton by measurement of Compton doublepolarization observables. Phys. Rev. C 102, no.3 (2020) 035205
  Paudyal, D.; Martel, P. P.; Huber, G. M.; Hornidge, D.; Abt, S.; Achenbach, P.; Adlarson, P.; Afzal, F.; Ahmed, Z.; Akondi, C. S.; Annand, J. R. M.; Arends, H. J.; Bashkanov, M.; Beck, R.; Biroth, M.; Borisov, N. S.; Braghieri, A.; Briscoe, W. J.; Cividini, F.; ... & Zana, L.
  
• Dispersive evaluation of the Lamb shift in muonic deuterium from chiral effective field theory. Phys. Rev. C 103, no.2 (2021) 024001
  Acharya, Bijaya; Lensky, Vadim; Bacca, Sonia; Gorchtein, Mikhail & Vanderhaeghen, Marc
  
• Isovector electromagnetic form factors of the nucleon from lattice QCD and the proton radius puzzle. Phys. Rev. D 103 (2021) 9, 094522
  Djukanovic, D.; Harris, T.; von Hippel, G.; Junnarkar, P. M.; Meyer, H. B.; Mohler, D.; Ottnad, K.; Schulz, T.; Wilhelm, J. & Wittig, H.
  
• Oscillating Features in the Electromagnetic Structure of the Neutron. Nature Physics (2021)
  Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ahmed, S.; Albrecht, M.; Aliberti, R.; Amoroso, A.; An, Q.; Lavania, Anita; Bai, X. H.; Bai, Y.; Bakina, O.; Ferroli, R. B.; Balossino, I.; Ban, Y.; Begzsuren, K.; Berger, N.; Bertani, M.; Bettoni, D.; ... & Zou, J. H.
  
• Search for the reaction channel e+ e− → ηc ηπ + π − at center-of-mass energies from 4.23 to 4.60 GeV. Phys. Rev. D 103 (2021) 032004
  Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ahmed, S.; Albrecht, M.; Alekseev, M.; Amoroso, A.; An, F. F.; An, Q.; Bai, Y.; Bakina, O.; Baldini Ferroli, R.; Balossino, I.; Ban, Y.; Begzsuren, K.; Bennett, J. V.; Berger, N.; Bertani, M.; Bettoni, D.; ... & Zou, J. H.