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The magnetic dipole, the electric quadrupole and the Coulomb quadrupole amplitudes for the transition \gamma N\to \Delta are calculated in quenched lattice QCD at \beta=6.0 with Wilson fermions. Using a new method combining an optimal…

High Energy Physics - Lattice · Physics 2008-11-26 C. Alexandrou , Ph. de Forcrand , H. Neff , J. W. Negele , W. Schroers , A. Tsapalis

The electromagnetic nucleon to Delta transition form factors are evaluated using two degenerate flavors of dynamical Wilson fermions and using dynamical sea staggered fermions with domain wall valence quarks. The two subdominant quadrupole…

High Energy Physics - Lattice · Physics 2008-11-26 C. Alexandrou , G. Koutsou , H. Neff , J. W. Negele , W. Schroers , A. Tsapalis

Calculations of the magnetic dipole, electric quadrupole and Coulomb quadrupole amplitudes for the transition $\gamma N\to \Delta$ are presented both in quenched QCD and with two flavours of degenerate dynamical quarks.

High Energy Physics - Lattice · Physics 2008-11-26 C. Alexandrou , Ph. de Forcrand , Th. Lippert , H. Neff , J. W. Negele , K. Schilling , W. Schroers , A. Tsapalis

We present results on the ratio of electric quadrupole to magnetic dipole amplitudes, $R_{EM}={\cal G}_{E2}/{\cal G}_{M1}$, for the transition $\gamma N to \Delta$ from lattice QCD. We consider both the quenched and the 2-flavor theory.

High Energy Physics - Lattice · Physics 2008-11-26 C. Alexandrou , Ph. de Forcrand , Th. Lippert , H. Neff , J. W. Negele , K. Schilling , W. Schroers , A. Tsapalis

We present recent lattice QCD results on the electroweak nucleon to $\Delta$ transition and $\Delta$ form factors using dynamical fermion gauge configurations with a lowest pion mass of about 300 MeV, with special emphasis in the…

High Energy Physics - Lattice · Physics 2019-08-15 Constantia Alexandrou

We present a new method to determine the momentum dependence of the N to Delta transition form factors and demonstrate its effectiveness in the quenched theory at $\beta=6.0$ on a $32^3 \times 64$ lattice. We address a number of technical…

High Energy Physics - Lattice · Physics 2008-11-26 C. Alexandrou , Ph. de Forcrand , H. Neff , J. W. Negele , W. Schroers , A. Tsapalis

Lattice results on the N to Delta electromagnetic, axial-vector and pseudoscalar form factors are evaluated using dynamical staggered sea quarks and domain wall valence quarks for pion masses in the range of 580-350 MeV, as well as,…

High Energy Physics - Lattice · Physics 2017-08-23 C. Alexandrou

We evaluate the N to Delta axial transition form factors in lattice QCD in the quenched theory, with two degenerate flavors of dynamical Wilson fermions and using domain wall valence fermions with staggered sea quark configurations. We…

High Energy Physics - Lattice · Physics 2008-11-26 C. Alexandrou , Th. Leontiou , J. W. Negele , A. Tsapalis

We discuss the techniques to extract the electromagnetic Delta form factors in Lattice QCD. We evaluate these form factors using dynamical fermions with smallest pion mass of about 350 MeV. We pay particular attention to the extraction of…

High Energy Physics - Lattice · Physics 2010-02-05 C. Alexandrou , T. Korzec , G. Koutsou , C. Lorcé , V. Pascalutsa , M. Vanderhaeghen , J. W. Negele , A. Tsapalis

We develop techniques to calculate the four Delta electromagnetic form factors using lattice QCD, with particular emphasis on the sub-dominant electric quadrupole form factor that probes deformation of the Delta. Results are presented for…

High Energy Physics - Lattice · Physics 2010-04-21 C. Alexandrou , T. Korzec , G. Koutsou , Th. Leontiou , C. Lorcé , J. W. Negele , V. Pascalutsa , A. Tsapalis , M. Vanderhaeghen

This work evaluates the model dependence of the electric and Coulomb quadrupole amplitudes (E2, C2) in the predominantly M1 (magnetic dipole-quark spin flip) gamma* N -> Delta transition. Both the model-to-model dependence and the intrinsic…

Nuclear Experiment · Physics 2011-04-11 S. Stave , A. M. Bernstein , I. Nakagawa

The N to Delta transition form factors GM1, GE2 and GC2 are evaluated using dynamical MILC configurations and valence domain wall fermions at three values of quark mass corresponding to pion mass 606 MeV, 502 MeV and 364 MeV on lattices of…

We calculate the electromagnetic, axial and pseudo-scalar form factors of the Nucleon to $\Delta(1232)$ transition using two dynamical light degenerate quarks and a dynamical strange quark simulated with the domain wall fermion action.…

High Energy Physics - Lattice · Physics 2011-02-25 C. Alexandrou , G. Koutsou , J. W. Negele , Y. Proestos , A. Tsapalis

Utilizing the methods of chiral effective field theory we present an analysis of the electromagnetic $N\Delta$-transition current in the framework of the non-relativistic "small scale expansion" (SSE) to leading-one-loop order. We discuss…

Nuclear Theory · Physics 2008-11-26 Tobias A. Gail , Thomas R. Hemmert

The electromagnetic, axial and pseudoscalar nucleon to Delta form factors are calculated using dynamical domain wall fermions at a lattice spacing of a = 0.114 fm on a lattice of spatial size 2.74 fm and pion mass of 331 MeV. Pion pole…

High Energy Physics - Lattice · Physics 2010-11-05 C. Alexandrou , G. Koutsou , J. W. Negele , A. O'Cais , Y. Proestos , A. Tsapalis

We present recent lattice QCD results on nucleon form factors and N to Delta transition form factors. We predict the parity violating asymmetry in N to Delta and check the off-diagonal Goldberger-Treiman relation.

High Energy Physics - Lattice · Physics 2007-05-23 C. Alexandrou

We study the N-Delta-gamma transition in the Dyson-Schwinger approach. The nucleon and Delta baryons are treated as quark-diquark bound states, where the ingredients of the electromagnetic transition current are computed self-consistently…

High Energy Physics - Phenomenology · Physics 2013-05-30 Gernot Eichmann , Diana Nicmorus

The magnetic dipole G_M(Q^2), electric quadrupole G_E(Q^2), and Coulomb quadrupole G_C(Q^2) form factors, describing the spin-3/2 to spin-1/2 electromagnetic transitions, are investigated within the light cone QCD sum rules. The Q^2…

High Energy Physics - Phenomenology · Physics 2015-06-16 T. M. Aliev , Y. Oktem , M. Savci

The electromagnetic N-$\Delta$ transition form factors are calculated in the framework of a formally covariant constituent diquark model. As a spin-3/2 particle the $\Delta$ is assumed to be a bound state of a quark and an axial-vector…

Nuclear Theory · Physics 2011-07-19 Volker Keiner

The \gamma* N -> \Delta(1232) transition is a window on hadron shape deformation, the applicability of perturbative QCD at moderate momentum transfers, and the influence of nonperturbative phenomena on hadronic observables. We explain that…

Nuclear Theory · Physics 2015-06-15 Jorge Segovia , Chen Chen , Craig D. Roberts , Shaolong Wan
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