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Martha ConstantinouAssistant Professor of PhysicsPh.D., University of CyprusSERC, Room 414
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Research Interests
My research interests focus on the aspects of Quantum Chromodynamics (QCD), and more precisely on the quantitative description of the properties of hadrons using Lattice QCD. This is achieved via calculations of key observables that characterize the structure of protons and neutrons, such as the electromagnetic and axial form factors, and the nucleon momentum carried by the quarks and gluons. These calculations allow us to address open question in hadron structure, for instance, the spin content of the nucleon and the proton radius puzzle.
Lattice QCD can provide input to on-going experiments, but also give predictions on observables that are either not easily accessible experimentally, or explore Physics beyond the Standard Model. A pioneering work of the latter type is the calculation of the nucleon σ-terms, which require very intensive computations, as well as significant algorithmic improvements. The nucleon σ-terms enter in the determination of the scattering cross section of dark matter candidates (typically SUSY neutralinos) on nucleons, and thus, have significant impact for any direct search of dark matter. My research involves the first ab initio calculation of the σ-terms in Lattice QCD using state-of-the-art simulations with quark masses at their physical value. In addition, the charm nucleon σ-term was presented for the first time. This kind of calculations of fundamental nucleon properties may provide a link towards probing the hidden physics of dark matter.
Solving QCD is deeply intertwined with High Performance Computer technologies, and numerical simulations of Lattice QCD require enormous computational resources provided by supercomputing facilities that are open to researchers on a competitive basis. My group has acquired such resources in some of the largest facilities, for example, the Juelich and the Swiss National Supercomputing Centers.
Lattice QCD can provide input to on-going experiments, but also give predictions on observables that are either not easily accessible experimentally, or explore Physics beyond the Standard Model. A pioneering work of the latter type is the calculation of the nucleon σ-terms, which require very intensive computations, as well as significant algorithmic improvements. The nucleon σ-terms enter in the determination of the scattering cross section of dark matter candidates (typically SUSY neutralinos) on nucleons, and thus, have significant impact for any direct search of dark matter. My research involves the first ab initio calculation of the σ-terms in Lattice QCD using state-of-the-art simulations with quark masses at their physical value. In addition, the charm nucleon σ-term was presented for the first time. This kind of calculations of fundamental nucleon properties may provide a link towards probing the hidden physics of dark matter.
Solving QCD is deeply intertwined with High Performance Computer technologies, and numerical simulations of Lattice QCD require enormous computational resources provided by supercomputing facilities that are open to researchers on a competitive basis. My group has acquired such resources in some of the largest facilities, for example, the Juelich and the Swiss National Supercomputing Centers.
Key Publications
- M. Constantinou, R. Horsley, H. Panagopoulos, H. Perlt, P. E. L. Rakow, G. Schierholz, A. Schiller, and J. M. Zanotti, "Renormalization of local quark-bilinear operators for Nf = 3 flavors of stout link nonperturbative clover fermions", Physical Review D 91, 014502 (2015) [arXiv:1408.6047].
- A. Abdel-Rehim, C. Alexandrou, M. Constantinou, P. Dimopoulos, R. Frezzotti, K. Hadjiyiannakou, K. Jansen, Ch. Kallidonis, B. Kostrzewa, G. Koutsou, M. Mangin-Brinet, M. Oehm, G. C. Rossi, C. Urbach, and U. Wenger, "Nucleon and pion structure with lattice QCD simulations at physical value of the pion mass", Physical Review D 93, 039904(E) (2016) [arXiv:1507.04936].
- C. Alexandrou, A. Athenodorou, M. Constantinou, K. Hadjiyiannakou, K. Jansen, G. Koutsou, K. Ottnad, and M. Petschlies, "Neutron electric dipole moment using Nf = 2 + 1 + 1 twisted mass fermions", Physical Review D 93, 074503 (2016) [arXiv:1510.05823].
- A. Abdel-Rehim, C. Alexandrou, M. Constantinou, K. Hadjiyiannakou, K. Jansen, Ch. Kallidonis, G. Koutsou, and A. Vaquero Avilés-Casco, "Direct Evaluation of the Quark Content of Nucleons from Lattice QCD at the Physical Point", Physical Review Letters 116, 252001 (2016) [arXiv:1601.01624].
- Constantia Alexandrou, Martha Constantinou, Giannis Koutsou, Konstantin Ottnad, and Marcus Petschlies, "A position space method for the nucleon magnetic moment in lattice QCD", Accepted in Physical Review D, [arXiv:1605.07327].
- C. Alexandrou, M. Constantinou, K. Hadjiyiannakou, K. Jansen, H. Panagopoulos, and C. Wiese, "Gluon momentum fraction of the nucleon from Lattice QCD”, submitted to Physical Review D.
Full list of publication can be found at the inSPIRE database