First Lattice Study of the $N$-$P_{11}(1440)$ Transition Form Factors

Experiments at Jefferson Laboratory, MIT-Bates, LEGS, Mainz, Bonn, GRAAL, and Spring-8 offer new opportunities to understand in detail how nucleon resonance ($N^{\ast }$) properties emerge from the nonperturbative aspects of QCD. Preliminary data from CLAS collaboration, which cover a large range of photon virtuality $Q^2$ show interesting behavior with respect to $Q^2$ dependence: in the region $Q^2\le 1.5{GeV}^2$, both the transverse amplitude, $A_{1\mathrm{/}2}(Q^2)$, and the longitudinal amplitude, $S_{1\mathrm{/}2}(Q^2)$, decrease rapidly. In this work, we attempt to use first-principles lattice QCD (for the first time) to provide a model-independent study of the Roper-nucleon transition form factor.