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We compute the one-loop lattice renormalization of the two-quark operators ψ̄Γψ, where Γ denotes the generic Dirac matrix, for the lattice formulation of QCD using the overlap-Dirac operator. We also study the renormalization of quark bilinears which are more extended and have better chiral properties. Finally, we present improved estimates of these… (More)

Since the early days of QCD, it has been argued that inside hadrons quarks organise into substructures. Among those, popular pictures of various phenomena (including exotica and colour superconductivity) give a prominent role to diquarks, i.e. to colour antitriplet combinations of two quarks. Using a gauge-invariant setup, which combines the diquark with a… (More)

- Abdou Abdel-Rehim, Constantia Alexandrou, Joshua Berlin, Mattia Dalla Brida, Jacob Finkenrath, Marc Wagner
- Computer Physics Communications
- 2017

We discuss and compare the efficiency of various methods, combinations of point-to-all propagators, stochastic timeslice-to-all propagators, the one-end trick and sequential propagators, to compute two-point correlation functions of two-quark and four-quark interpolating operators of different structure including quark-antiquark type, mesonic molecule type,… (More)

- Constantia Alexandrou, Jan O. Daldrop, +4 authors Marc Wagner
- 2012

We carry out an exploratory study of the isospin one a0(980) and the isospin one-half κ scalar mesons using Nf = 2 + 1 + 1 Wilson twisted mass fermions at one lattice spacing. The valence strange quark is included as an Osterwalder-Seiler fermion with mass tuned so that the kaon mass matches the corresponding mass in the unitary Nf = 2+1+1 theory. We… (More)

- Constantia Alexandrou, Ph de Forcrand, Biagio Lucini
- Physical review letters
- 2006

Diquarks may play an important role in hadron spectroscopy, baryon decays, and color superconductivity. We investigate the existence of diquark correlations in lattice QCD by considering systematically all the lowest energy diquark channels in a color gauge-invariant setup. We measure mass differences between the various channels and show that the positive… (More)

We compute the ratio ΛL/ΛMS between the scale parameter ΛL, associated with a lattice formulation of QCD using the overlap-Dirac operator, and ΛMS of the MS renormalization scheme. To this end, the necessary one-loop relation between the lattice coupling g0 and the coupling renormalized in the MS scheme is calculated, using the lattice background field… (More)

1Goethe-Universität Frankfurt am Main, Institut für theoretische Physik, Max-von-Laue-Straße 1, D-60438 Frankfurt am Main, Germany 2Computation-based Science and Technology Research Center, The Cyprus Institute, 20 Kavafi Street, 2121 Nicosia, Cyprus 3Department of Physics, University of Cyprus, P.O. Box 20537, 1678 Nicosia, Cyprus 4NIC, DESY, Platanenallee… (More)

- Marc Wagner, Constantia Alexandrou, +5 authors Christian Wiese
- 2012

1 Goethe-Universität Frankfurt am Main, Institut für Theoretische Physik, Max-von-Laue-Straße 1, D-60438 Frankfurt am Main, Germany 2 Department of Physics, University of Cyprus, P.O. Box 20537, 1678 Nicosia, Cyprus 3 Computation-based Science and Technology Research Center, Cyprus Institute, 20 Kavafi Str., Nicosia 2121, Cyprus 4 Helmholtz-Institut für… (More)

- Marc Wagner, Constantia Alexandrou, +5 authors Christian Wiese
- 2012

We study the light scalar mesons a0(980) and κ using N f = 2+ 1+ 1 flavor lattice QCD. In order to probe the internal structure of these scalar mesons, and in particular to identify, whether a sizeable tetraquark component is present, we use a large set of operators, including diquarkantidiquark, mesonic molecule and two-meson operators. The inclusion of… (More)

- Marc Wagner, Abdou Abdel-Rehim, +5 authors Carsten Urbach
- 2013

We review the status of an ongoing long-term lattice investigation of the spectrum and structure of tetraquark candidates. We focus on the light scalar meson a0(980). First steps regarding the study of a possibly existing ccc̄c̄ tetraquark are also outlined.