Ruben Sandapen

Color dipoles and ρ, Φ electroproduction

We present a detailed comparison of a variety of predictions for diffractive light vector meson production with the data collected at the HERA collider. All our calculations are performed within a dipole model framework and make use of different models for the meson light-cone wavefunction. There are no free parameters in any of the scenarios we consider. Generally we find good agreement with the data using rather simple Gaussian motivated wavefunctions in conjunction with dipole cross-sections which have been fitted to other data.

Further success of the colour dipole model

We confront a very wide body of HERA diffractive electroproduction data with the predictions of the colour dipole model. We focus upon three different parameterisations of the dipole scattering cross-section and find good agreement for all observables. There can be no doubting the success of the dipole scattering approach and more precise observations are needed in order to expose its limitations.

Diffractive upsilon production at the LHC

We compute the rate for diffractive meson production at the Tevatron and the LHC. The is produced diffractively via the subprocess ?+p ? +p where the initial photon is radiated off an incoming proton (or antiproton). We consider the possibility to use low angle proton detectors to make a measurement of the ?p cross-section and conclude that a measurement of the cross-section at a centre of mass energy in excess of 1 TeV is possible at the LHC. This is in the region where saturation effects are likely to reveal themselves.

Extracting the ρ meson wavefunction from HERA data

We extract the light-cone wavefunctions of the ρ meson using the HERA data on diffractive ρ photoproduction. We find good agreement with predictions for the distribution amplitude based on QCD sum rules and from the lattice. We also find that the data prefer a transverse wavefunction with enhanced end-point contributions.

Extracting the Distribution Amplitudes of the ρ meson from the Color Glass Condensate

We extract the twist-2 and twist-3 Distribution Amplitudes (DAs) of the ρ meson using the HERA data on diffractive ρ photoproduction. We do so using several Colour Glass Condensate (CGC) inspired and a Regge inspired dipole models. We find that our extracted twist-2 DA is not much model dependent and is consistent with QCD Sum Rules and lattice predictions. The extracted twist-3 DA is more model dependent but is still consistent with the Sum Rules prediction.

Diffractive vector meson production at HERA using holographic AdS/QCD wavefunctions

We demonstrate another success of the AdS/QCD correspondence by showing that an AdS/QCD holographic light-front wavefunction for the \

Diffractive ρ production with an AdS/QCD holographic wavefunction for the ρ meson

{\textbackslash}rho\

An AdS/QCD holographic wavefunction for the rho meson

meson generates predictions for the cross-sections of diffractive \

Predictions for diffractive ɸ meson production using an AdS/QCD light-front wavefunction

{\textbackslash}rho\

Dynamical spin effects in the pion

production that are in agreement with data collected at the HERA electron-proton collider.