Browsing by Author "Constantinou, Martha"
Now showing items 1-20 of 36
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Axial nucleon form factors from lattice QCD
Alexandrou, Constantia; Brinet, M.; Carbonell, J.; Constantinou, Martha; Harraud, P. A.; Guichon, P.; Jansen, K.; Korzec, T.; Papinutto, M. (2011)We present results on the nucleon axial form factors within lattice QCD using two flavors of degenerate twisted mass fermions. Volume effects are examined using simulations at two volumes of spatial length L=2.1fm and ...
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Article
A complete non-perturbative renormalization prescription for quasi-PDFs
Alexandrou, Constantia; Cichy, K.; Constantinou, Martha; Hadjiyiannakou, Kyriakos; Jansen, K.; Panagopoulos, Haralambos G.; Steffens, F. (2017)In this work we present, for the first time, the non-perturbative renormalization for the unpolarized, helicity and transversity quasi-PDFs, in an RI′ scheme. The proposed prescription addresses simultaneously all aspects ...
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Direct Evaluation of the Quark Content of Nucleons from Lattice QCD at the Physical Point
Abdel-Rehim, A.; Alexandrou, Constantia; Constantinou, Martha; Hadjiyiannakou, Kyriakos; Jansen, K.; Kallidonis, Christos; Koutsou, Giannis; Avilés-Casco, A. V. (2016)We evaluate the light, strange, and charm scalar content of the nucleon using one lattice QCD ensemble generated with two degenerate light quarks with mass fixed to their physical value. We use improved techniques to ...
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Conference Object
Disconnected diagrams with twisted-mass fermions
Abdel-Rehim, A.; Alexandrou, Constantia; Constantinou, Martha; Finkenrath, J.; Hadjiyiannakou, Kyriakos; Jansen, K.; Kallidonis, Christos; Koutsou, Giannis; Avilés-Casco, A. V.; Volmer, J. (Proceedings of Science (PoS), 2016)The latest results from the Twisted-Mass collaboration on disconnected diagrams at the physical value of the pion mass are presented. In particular, we focus on the sigma terms, the axial charges and the momentum fraction, ...
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Article
Disconnected quark loop contributions to nucleon observables in lattice QCD
Abdel-Rehim, A.; Alexandrou, Constantia; Constantinou, Martha; Drach, V.; Hadjiyiannakou, Kyriakos; Jansen, K.; Koutsou, Giannis; Vaquero, A. (2014)We perform a high statistics calculation of disconnected fermion loops on graphics processing units for a range of nucleon matrix elements extracted using lattice QCD. The isoscalar electromagnetic and axial vector form ...
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Conference Object
Disconnected quark loop contributions to nucleon observables using Nf = 2 twisted clover fermions at the physical value of the light quark mass
Abdel-Rehim, A.; Alexandrou, Constantia; Constantinou, Martha; Hadjiyiannakou, Kyriakos; Jansen, K.; Kallidonis, Christos; Koutsou, Giannis; Avilés-Casco, A. V. (Proceedings of Science (PoS), 2015)We compute the disconnected quark loops contributions entering the determination of nucleon observables, by using a Nf = 2 ensemble of twisted mass fermions with a clover term at a pION mass mπ = 133 MeV. We employ exact ...
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Article
Double Networks Based on Amphiphilic Cross-Linked Star Block Copolymer First Conetworks and Randomly Cross-Linked Hydrophilic Second Networks
Rikkou-Kalourkoti, Maria D.; Kitiri, E. N.; Patrickios, Costas S.; Leontidis, Epameinondas; Constantinou, Martha; Constantinides, G.; Zhang, X. K.; Papadakis, Christine M. (2016)This study presents the preparation and characterization of double networks (DN) based on a first amphiphilic polymethacrylate conetwork (APCN) and a second polyacrylamide network. The APCN first network comprised ...
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Conference Object
The electric dipole moment of the neutron from Nf = 2+1+1 twisted mass fermions
Petschlies, Marcus; Alexandrou, Constantia; Athenodorou, A.; Constantinou, Martha; Hadjiyiannakou, Kyriakos; Jansen, K.; Koutsou, Giannis; Ottnad, K. (Proceedings of Science (PoS), 2015)We extract the neutron electric dipole moment (nEDM) dn on configurations produced with Nf = 2+1+1 twisted mass fermions with lattice spacing of a ≃ 0.082fm and a light quark mass that correpsonds to Mπ ≃ 373 MeV. We do ...
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Article
Erratum: Nucleon and pion structure with lattice QCD simulations at physical value of the pion mass (Physical Review D - Particles, Fields, Gravitation and Cosmology (2015) 92 (114513))
Abdel-Rehim, A.; Alexandrou, Constantia; Constantinou, Martha; Dimopoulos, Petros; Frezzotti, R.; Hadjiyiannakou, Kyriakos; Jansen, K.; Kallidonis, Christos; Kostrzewa, B.; Koutsou, Giannis; Mangin-Brinet, M.; Oehm, M.; Rossi, G. C.; Urbach, C.; Wenger, U. (2016)We present results on the nucleon scalar, axial, and tensor charges as well as on the momentum fraction and the helicity and transversity moments. The pion momentum fraction is also presented. The computation of these key ...
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Article
Evaluation of disconnected quark loops for hadron structure using GPUs
Alexandrou, Constantia; Constantinou, Martha; Drach, V.; Hadjiyiannakou, Kyriakos; Jansen, K.; Koutsou, Giannis; Strelchenko, A.; Vaquero, A. (2014)A number of stochastic methods developed for the calculation of fermion loops are investigated and compared, in particular with respect to their efficiency when implemented on Graphics Processing Units (GPUs). We assess ...
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Article
First moment of the flavour octet nucleon parton distribution function using lattice QCD
Alexandrou, Constantia; Constantinou, Martha; Dinter, S.; Drach, V.; Hadjiyiannakou, Kyriakos; Jansen, K.; Koutsou, Giannis; Vaquero, A. (2015)Abstract: We perform a lattice computation of the flavour octet contribution to the average quark momentum in the nucleon, (Formula presented.). In particular, we fully take the disconnected contributions into account in ...
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Article
First physics results at the physical pion mass from Nf=2 Wilson twisted mass fermions at maximal twist
Petschlies, Marcus; Abdel-Rehim, A.; Alexandrou, Constantia; Burger, F.; Constantinou, Martha; Dimopoulos, Petros; Frezzotti, R.; Hadjiyiannakou, Kyriakos; Helmes, C.; Jansen, K.; Jost, C.; Kallidonis, Christos; Knippschild, B.; Kostrzewa, B.; Koutsou, Giannis; Liu, L.; Mangin-Brinet, M.; Ottnad, K.; Pientka, G.; Rossi, G. C.; Urbach, C.; Wenger, U.; Werner, M. (2017)We present physics results from simulations of QCD using Nf=2 dynamical Wilson twisted mass fermions at the physical value of the pion mass. These simulations are enabled by the addition of the clover term to the twisted ...
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Article
Magnetic susceptibility of QCD at zero and at finite temperature from the lattice
Bali, G. S.; Bruckmann, F.; Constantinou, Martha; Costa, Marios Gil; Endrödi, Gergely; Katz, Sándor D.; Panagopoulos, Haralambos G.; Schäfer, A. (2012)The response of the QCD vacuum to a constant external (electro)magnetic field is studied through the tensor polarization of the chiral condensate and the magnetic susceptibility at zero and at finite temperature. We determine ...
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Article
Moments of nucleon generalized parton distributions from lattice QCD
Alexandrou, Constantia; Carbonell, J.; Constantinou, Martha; Harraud, P. A.; Guichon, P.; Jansen, K.; Kallidonis, Christos; Korzec, T.; Papinutto, M. (2011)We present results on the lower moments of the nucleon generalized parton distributions within lattice QCD using two dynamical flavors of degenerate twisted mass fermions. Our simulations are performed on lattices with ...
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Article
Neutron electric dipole moment using Nf=2+1+1 twisted mass fermions
Petschlies, Marcus; Alexandrou, Constantia; Athenodorou, A.; Constantinou, Martha; Hadjiyiannakou, Kyriakos; Jansen, K.; Koutsou, Giannis; Ottnad, K. (2016)We evaluate the neutron electric dipole moment |d→N| using lattice QCD techniques. The gauge configurations analyzed are produced by the European Twisted Mass Collaboration using Nf=2+1+1 twisted mass fermions at one value ...
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Article
Nucleon and pion structure with lattice QCD simulations at physical value of the pion mass
Abdel-Rehim, A.; Alexandrou, Constantia; Constantinou, Martha; Dimopoulos, Petros; Frezzotti, R.; Hadjiyiannakou, Kyriakos; Jansen, K.; Kallidonis, Christos; Kostrzewa, B.; Koutsou, Giannis; Mangin-Brinet, M.; Oehm, M.; Rossi, G. C.; Urbach, C.; Wenger, U. (2015)We present results on the nucleon scalar, axial, and tensor charges as well as on the momentum fraction, and the helicity and transversity moments. The pion momentum fraction is also presented. The computation of these key ...
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Conference Object
Nucleon electromagnetic and axial form factors with Nf=2 twisted mass fermions at the physical point
Alexandrou, Constantia; Constantinou, Martha; Hadjiyiannakou, Kyriakos; Kallidonis, Christos; Koutsou, Giannis; Jansen, K.; Ottnad, K.; Vaquero, A. (Proceedings of Science (PoS), 2016)We present results for the nucleon electromagnetic and axial form factors using an Nf=2 twisted mass fermion ensemble with pion mass of about 131 MeV. We use multiple sink-source separations to identify excited state ...
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Article
Nucleon electromagnetic form factors in twisted mass lattice QCD
Alexandrou, Constantia; Brinet, M.; Carbonell, J.; Constantinou, Martha; Harraud, P. A.; Guichon, P.; Jansen, K.; Korzec, T.; Papinutto, M. (2011)We present results on the nucleon electromagnetic form factors within lattice QCD using two flavors of degenerate twisted mass fermions. Volume effects are examined using simulations at two volumes of spatial length L=2.1fm ...
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Article
Nucleon electromagnetic form factors using lattice simulations at the physical point
Alexandrou, Constantia; Constantinou, Martha; Hadjiyiannakou, Kyriakos; Jansen, K.; Kallidonis, Christos; Koutsou, Giannis; Vaquero Aviles-Casco, A. (2017)We present results for the nucleon electromagnetic form factors using an ensemble of maximally twisted mass clover-improved fermions with pion mass of about 130 MeV. We use multiple sink-source separations and three analysis ...
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Article
Nucleon form factors and moments of generalized parton distributions using Nf=2+1+1 twisted mass fermions
Alexandrou, Constantia; Constantinou, Martha; Dinter, S.; Drach, V.; Jansen, K.; Kallidonis, Christos; Koutsou, Giannis (2013)We present results on the axial and the electromagnetic form factors of the nucleon, as well as on the first moments of the nucleon generalized parton distributions using maximally twisted mass fermions. We analyze two N ...