1,807 research outputs found
Cluster algebras in scattering amplitudes with special 2D kinematics
We study the cluster algebra of the kinematic configuration space
of a n-particle scattering amplitude restricted to the
special 2D kinematics. We found that the n-points two loop MHV remainder
function found in special 2D kinematics depend on a selection of
\XX-coordinates that are part of a special structure of the cluster algebra
related to snake triangulations of polygons. This structure forms a necklace of
hypercubes beads in the corresponding Stasheff polytope. Furthermore in , the cluster algebra and the selection of \XX-coordinates in special 2D
kinematics replicates the cluster algebra and the selection of \XX-coordinates
of two loop MHV amplitude in 4D kinematics.Comment: 22 page
Towards Relativistic Skyrmions
We revisit baryons in the Skyrme model. Starting from static baryons in the
helicity eigenstates, we generalize their wavefunctions to the non-static and
relativistic regime. A new representation for gamma matrices in the soliton
collective space is constructed and the corresponding Dirac equation is
obtained. As an example, we draw consideration on how to apply this new
representation on the calculus of vector current vacuum expectation values for
baryon states of spin and isospin half and arbitrary momenta and we show how
elastic form factors can be derived.Comment: 7 pages, 7th Conference Mathematical Methods in Physics - Londrina
2012, Rio de Janeiro, Brazi
Generalized baryon form factors and proton structure functions in the Sakai-Sugimoto model
We investigate the production of positive parity baryon resonances in proton
electromagnetic scattering within the Sakai-Sugimoto model. The latter is a
string model for the non-perturbative regime of large QCD. Using
holographic techniques we calculate the generalized Dirac and Pauli form
factors that describe resonance production. We use these results to estimate
the contribution of resonance production to the proton structure functions.
Interestingly, we find an approximate Callan-Gross relation for the structure
functions in a regime of intermediate values of the Bjorken variable.Comment: v3: 38 pages, 25 figures. We added a new subsection in order to
compare our results with experimental data. To appear in Nucl. Phys.
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