A first look at Au+Au collisions at RHIC energies using the PHOBOS detector
Birger Back M D Baker D S Barton R R Betts R Bindel A Budzanowski W Busza A Carroll J Corbo M P Decowski E Garcia N George K Gulbrandsen S Gushue C Halliwell J Hamblen G A Heintzelman C Henderson D Hicks D J Hofman R Hollis R Holyńiski B Holzman A Iordanova E Johnson J L Kane J Katzy N Khan W Kucewicz P Kulinich C M Kuo W T Lin S Manly D McLeod J Michalowski A C Mignerey J Mülmenstädt R Nouicer A Olszewski R Pak I C Park H Pernegger M Rafelski M Rbeiz C Reed L P Remsberg M Reuter C Roland G Roland L Rosenberg J Sagerer P Sarin P Sawicki W Skulski S G Steadman P Steinberg G S F Stephans M Stodulski A Sukhanov J-L Tang R Teng A Trzupek C Vale G J van Nieuwenhuizen R Verdier B Wadsworth F L H Wolfs B Wosiek K Woźniak A H Wuosmaa B Wyslouch
The PHOBOS detector has been used to study Au + Au collisions at√sNN = 56,130, and 200 GeV Several global observables have been measured and the results are compared with theoretical models. These observables include the charged-particle multiplicity measured as a function of beam energy, pseudo-rapidity, and centrality of the collision. A unique feature of the PHOBOS detector is its almost complete angular coverage such that these quantities can be studied over a pseudo-rapidity interval of |η|≤5.4. This allows for an almost complete integration of the total charged particle yield, which is found to be about Nchtot= 4200 ±470 at √sNN = 130 GeV and Nchtot = 5300 ±530 at √sNN = 200 GeV.
The ratio of anti-particles to particles emitted in the mid-rapidity region has also been measured using the PHOBOS magnetic spectrometer. Of particular interest is the ratio of anti-protons to protons in the mid-rapidity region, which was found to be (i.e.921-1) at √sNN = 130 GeV. This high value suggests that an almost baryon-free region has been produced in the collisions.
Birger Back1 M D Baker2 D S Barton2 R R Betts3 R Bindel4 A Budzanowski5 W Busza6 A Carroll2 J Corbo2 M P Decowski6 E Garcia3 N George1 K Gulbrandsen6 S Gushue2 C Halliwell3 J Hamblen7 G A Heintzelman2 C Henderson6 D Hicks2 D J Hofman3 R Hollis3 R Holyńiski5 B Holzman2 5 A Iordanova3 E Johnson7 J L Kane6 J Katzy3 6 N Khan7 W Kucewicz3 P Kulinich6 C M Kuo8 W T Lin8 S Manly7 D McLeod3 J Michalowski5 A C Mignerey4 J Mülmenstädt6 R Nouicer3 A Olszewski2 5 R Pak2 I C Park7 H Pernegger6 M Rafelski2 M Rbeiz6 C Reed6 L P Remsberg2 M Reuter3 C Roland6 G Roland6 L Rosenberg6 J Sagerer3 P Sarin6 P Sawicki5 W Skulski7 S G Steadman6 P Steinberg2 G S F Stephans6 M Stodulski5 A Sukhanov2 J-L Tang8 R Teng7 A Trzupek5 C Vale6 G J van Nieuwenhuizen6 R Verdier6 B Wadsworth6 F L H Wolfs7 B Wosiek5 K Woźniak5 A H Wuosmaa1 B Wyslouch6
Volume 93 | Issue 5
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