Description
We shall present preliminary results of the physics program with tagged forward protons with the STAR detector at RHIC. The results were obtained in proton-proton collisions at the √s = 200 GeV, with 18 pb−1 of data. The forward protons are detected in the Roman Pots while the recoil system is measured in the central detector of STAR whose two major systems for this program are the Time Projection Chamber (TPC) and the barrel Time-Of-Flight detector (TOF).The final state proton(s) were tagged in the STAR Roman Pot system while the identified charged particle tracks were reconstructed in the STAR Time Projection Chamber (TPC).
The measurements to be discussed are: a) Central Exclusive Production process pp →
pXp (CEP), which is dominated by the Double Pomeron Exchange (DPE) mechanism,
at this center-of-mass energy; b) Spectra of identified charged particles as pions, kaons and protons and their anti-particle counterparts in Single Diffraction (p + p → p + X) and Central Diffraction (p + p → p + X + p) processes. The proton-antiproton production asymmetry as a function of rapidity will also presented to study the baryon number transfer over a large space in rapidity in single diffraction dissociation process shall be discussed. For the CEP, the central diffractive system is measured in the TPC and the forward protons in the Roman Pots. Hence the exclusivity of the system can be determined by measuring its missing transverse momentum. Using the TPC and TOF for particle iden-
tification (PID) various production channels in pp → pXp reaction can be identified. We shall present preliminary results on exclusive production of two charged particles in mid-rapidity region, |η| < 1, with small squared
four-momentum transfer of forward protons, 0.03 < |t1|, |t2| < 0.3 (GeV/c)^2.
