Wyniki wyszukiwania - BazTech

1

Transverse momentum distributions and string percolation study in p+p, d+Au and Au+Au collisions at square rootsNN = 200 GeV

Srivastava B., Scharenberg R., Tarnowsky T.

Nukleonika

|

2006

|

Vol. 51,suppl.3

109-112

EN

Multiparticle production at high energies is described in terms of color strings stretched between the projectile and target. As string density increases, overlap among the strings leads to cluster formation. At some critical density, a macroscopic cluster appears, spanning the entire system. This marks the percolation phase transition. Data from p+p, d+Au and Au+Au collisions at 200 GeV has been analyzed using the STAR detector to obtain the percolation density parameter, eta. For 200 GeV Au+Au collisions, the value of h is found to lie above the critical percolation threshold, while for 200 GeV d+Au collisions it is below the critical value. This supports the idea of string percolation, which at high enough string density is a possible mechanism to explore the hadronic phase transition to a quark-gluon plasma.

2

Preliminary results on direct photon-photon HBT measurements in square root sNN = 62.4 GeV and 200 GeV Au+Au collisions at RHIC

Das D., Lin G., Chattopadhyay S., Chikanian A., Finch E., Nayak T., Panitkin S., Sandweiss J., Suaide A., Zhang H.

Nukleonika

|

2006

|

Vol. 51,suppl.3

55--58

EN

We present the preliminary results on direct photon interferometry measurements in Au+Au collisions at square root sNN = 62.4 GeV and 200 GeV using the STAR (solenoidal tracker at RHIC) detector. Photons are reconstructed via e+/e- conversions in STAR Time Projection Chamber (TPC) and energy deposited by photons in STAR Barrel Electromagnetic Calorimeter (BEMC). The two-photon correlations are measured using (1) both photons measured with BEMC; (2) one photon from conversions and the other measured with BEMC. Both the methodologies and the possible constraints in the correlation function measurements are discussed.

3

Baryon-baryon correlations in Au+Au collisions at square root sNN = 62 GeV and square root sNN = 200 GeV, measured in the STAR experiment at RHIC

Gos H.

Nukleonika

|

2006

|

Vol. 51,suppl.3

59-63

EN

Particle correlations at small relative velocities can be used to study the space-time evolution of hot and expanding system created in heavy-ion collisions. Baryon and antibaryon source sizes extracted from baryon-baryon correlations complement the information deduced from the correlation studies of identical pions. Correlations of nonidentical particles are sensitive also to the space-time asymmetry of their emission. High statistics data set of STAR experiment allows us to present the results of baryon-baryon correlation measurements at various centralities and energies, as well as to take carefully into account the particle identification probability and the fraction of primary baryons and antibaryons. Preliminary results show significant contribution of annihilation channel in baryon-antibaryon correlations.

4

Pion interferometry in Au+Au collisions at square root sNN = 200 GeV

Noriega M.

Nukleonika

|

2004

|

Vol. 49,suppl.2

67-70

EN

We present preliminary results from a two-pion intensity interferometry analysis from Au+Au collisions at square root sNN = 200 GeV measured in the STAR detector at RHIC. The dependence of the apparent pion source on multiplicity and transverse momentum are discussed and compared with preliminary results from d+Au and p+p collisions at the same beam energy.