Browsing Τμήμα Φυσικής / Department of Physics by Author "Jansen, K."

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 ...

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 ...

Article

Non-perturbative renormalization of quark bilinear operators with N f = 2 (tmQCD) Wilson fermions and the tree-level improved gauge action

Constantinou, Martha G.; Dimopoulos, Petros; Frezzotti, R.; Herdoiza, G.; Jansen, K.; Lubicz, V.; Panagopoulos, Haralambos G.; Rossi, G. C.; Simula, S.; Stylianou, Fotos S.; Vladikas, A. (2010)

We present results for the renormalization constants of bilinear quark operators obtained by using the tree-level Symanzik improved gauge action and the N f = 2 twisted mass fermion action at maximal twist, which guarantees ...

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 ...

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 ...

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 ...

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 ...

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 ...

Conference Object

Nucleon form factors with NF=2 twisted mass fermions

Guichon, P.; Baron, R.; Alexandrou, Constantia; Korzec, T.; Koutsou, Giannis; Brinet, M.; Carbonell, J.; Harraud, P. -A; Jansen, K. (2010)

We present results on the nucleon form factors using two degenerate flavors of twisted mass fermions on 243×48 and 32×64 lattices with pion masses in the range 290÷485MeV. © 2010 American Institute of Physics.

Conference Object

Nucleon generalized form factors with twisted mass fermions

Alexandrou, Constantia; Constantinou, Martha; Drach, V.; Jansen, K.; Kallidonis, Christos; Koutsou, Giannis (Proceedings of Science (PoS), 2013)

We present results on the nucleon form factors, momentum fraction and helicity moment for Nf = 2 and Nf = 2+1+1 twisted mass fermions for a number of lattice volumes and lattice spacings. First results for a new Nf = 2 ...

Article

Nucleon scalar and tensor charges using lattice QCD simulations at the physical value of the pION mass

Alexandrou, Constantia; Constantinou, Martha; Dimopoulos, Petros; Frezzotti, R.; Hadjiyiannakou, Kyriakos; Jansen, K.; Kallidonis, Christos; Kostrzewa, B.; Koutsou, Giannis; Mangin-Brinet, M.; Vaquero Avilès-Casco, A.; Wenger, U. (2017)

We present results on the light, strange and charm nucleon scalar and tensor charges from lattice QCD, using simulations with Nf=2 flavors of twisted mass clover-improved fermions with a physical value of the pION mass. ...

Conference Object

Nucleon spin and quark content at the physical point

Alexandrou, Constantia; Constantinou, Martha; Hadjiyiannakou, Kyriakos; Kallidonis, Christos; Koutsou, Giannis; Jansen, K.; Wiese, C.; Avilés-Casco, A. V. (Proceedings of Science (PoS), 2016)

We present results on the spin and quark content of the nucleon using Nf =2 twisted mass cloverimproved fermion simulations with a pion mass close to its physical value. We use recently developed methods to obtain accurate ...

Article

Nucleon structure using lattice QCD

Alexandrou, Constantia; Constantinou, Martha; Drach, V.; Hadjiyiannakou, Kyriakos; Jansen, K.; Kallidonis, Christos; Koutsou, Giannis; Leontiou, Theodoros; Vaquero, A. (2013)

A review of recent nucleon structure calculations within lattice QCD is presented. The nucleon excited states, the axial charge, the isovector momentum fraction and helicity distribution are discussed, assessing the methods ...

Conference Object

Parton distributions from lattice QCD with momentum smearing

Alexandrou, Constantia; Cichy, K.; Constantinou, Martha; Hadjiyiannakou, Kyriakos; Jansen, K.; Steffens, F.; Wiese, C. (Proceedings of Science (PoS), 2016)

In this work we continue our effort to explore a recent proposal, which allows light-cone distributions to be extracted from purely spatial correlations, being thus accessible to lattice methods. In order to test the ...

Article

Precision study of excited state effects in nucleon matrix elements

Dinter, S.; Alexandrou, Constantia; Constantinou, Martha G.; Drach, V.; Jansen, K.; Renner, D. B. (2011)

We present a dedicated analysis of the influence of excited states on the calculation of nucleon matrix elements. This calculation is performed at a fixed value of the lattice spacing, volume and pion mass that are typical ...

Conference Object

The quark contents of the nucleon and their implication for dark matter search

Alexandrou, Constantia; Constantinou, Martha; Drach, V.; Hadjiyiannakou, Kyriakos; Jansen, K.; Koutsou, Giannis; Strelchenko, A.; Vaquero, A. (Proceedings of Science (PoS), 2013)

We present results concerning the light and strange quark contents of the nucleon using Nf = 2+1+1 flavours of maximally twisted mass fermions. The corresponding σ- Terms are casting light on the origin of the nucleon mass ...

Conference Object

Recent results for the proton spin decomposition from lattice QCD

Alexandrou, Constantia; Constantinou, Martha; Hadjiyiannakou, Kyriakos; Kallidonis, Christos; Koutsou, Giannis; Jansen, K.; Panagopoulos, Haralambos G.; Steffens, F.; Vaquero, A.; Wiese, C. (Proceedings of Science (PoS), 2016)

The exact decomposition of the proton spin has been a much debated topic, on the experimental as well as the theoretical side. In this talk we would like to report on recent non-perturbative results and ongoing efforts to ...

Conference Object

Sigma- Terms and axial charges for hyperons and charmed baryons

Alexandrou, Constantia; Hadjiyiannakou, Kyriakos; Jansen, K.; Kallidonis, Christos (Proceedings of Science (PoS), 2013)

We present results for the s- Terms and axial charges for various hyperons and charmed baryons using Nf = 2+1+1 twisted mass fermions. For the computation of the three-point function we use the fixed current method. For ...

Article

A stochastic method for computing hadronic matrix elements

Alexandrou, Constantia; Constantinou, Martha; Dinter, S.; Drach, V.; Jansen, K.; Hadjiyiannakou, Kyriakos; Renner, D. B. (2014)

We present a stochastic method for the calculation of baryon three-point functions that is more versatile than the typically used sequential method. We analyze the scaling of the error of the stochastically evaluated ...

Article

Strangeness of the nucleon from lattice QCD

Alexandrou, Constantia; Constantinou, Martha; Dinter, S.; Drach, V.; Hadjiyiannakou, Kyriakos; Jansen, K.; Koutsou, Giannis; Vaquero, A. (2015)

We present a nonperturbative calculation of the strangeness of the nucleon yN within the framework of lattice QCD. This observable is known to be an important cornerstone to interpret results from direct dark matter detection ...