Hard-scattering in p-p collisions was discovered in 1972 at the CERN-ISR, the first hadron collider. Techniques were developed and several hard-processes were discovered which form the basis for many of the measurements made in p-p and Au+Au collisions at RHIC. Recent measurements of hard-scattering and related reactions by the PHENIX experiment at RHIC are presented in this context.

We discuss the onset of the dominance of the Glauber-GribovLandshoff (GGL) component of pQCD hard two-gluon (2G) exchange contribution to hard elastic ππ scattering at moderate energies . Such a hard ππ scattering could via final state interaction on the γγ → π+π− reaction in which pQCD quark-exchange contribution is known to be short of strength. While in the nonrelativistic approximation the ...

We consider high-energy fixed-angle scattering of glueballs in confining gauge theories that have supergravity duals. Although the effective description is in terms of the scattering of strings, we find that the amplitudes are hard (power law). This is a consequence of the warped geometry of the dual theory, which has the effect that in an inertial frame the string process is never in the soft ...

The interaction region of hard exclusive hadron scattering can have a large transverse size due to endpoint contributions, where one parton carries most of the hadron momentum. The endpoint region is enhanced and can dominate in processes involving multiple scattering and quark helicity flip. The endpoint Fock states have perturbatively short lifetimes, hence are not Sudakov suppressed and scat...

This report summarizes some of the recent HERA results obtained by studying hard processes in ep–scattering. By resolving the structure of the proton, hard ep– reactions provide information on the parton content of the proton and may give insight into the dynamics of the exchanged parton cascade. In addition, their study offers the possibility to test the Standard Model, in particular perturbat...

Hard scattering in p-p collisions, discovered at the CERN ISR in 1972 by the method of leading particles, proved that the partons of Deeply Inelastic Scattering strongly interacted with each other. Further ISR measurements utilizing inclusive single or pairs of hadrons established that high pT particles are produced from states with two roughly back-to-back jets which are the result of scatteri...

We review the extension of the factorization formalism for perturbative QCD to soft initialand final-state scattering associated with hard processes in nuclei.

It is now clear that there is a substantial population of primordial binaries in galactic globular clusters and that binary interactions are a major influence on globular cluster evolution. Collisional interactions involving stars in binaries may provide a significant channel for the formation of various stellar exotica, such as blue stragglers, X–ray binaries and millisecond pulsars. We report...

We present data from ir~p •*• elastic and p~p final states for scattering at 90° center of mass, -t = 9 GeV/c. A large p~p signal is seen and the p" are strongly polarized. This polarization tests a QCD prediction that quarks cannot flip helicity. The test fails dramatically. Exclusive two-body to two-body scattering at large momentum transfer represents a new laboratory for the study of hard s...