The PHOBOS detector at RHIC

Back, B. B.; Baker, M. D.; Barton, D. S.; Basilev, S.; Baum, R.; Betts, R. R.; Białas, A.; Bindel, R.; Bogucki, W.; Budzanowski, A.; Busza, W.; Carroll, A.; Ceglia, M.; Chang, Y. H.; Chen, A.E; Coghen, T.; Connor, C; Czyż, W.; Dąbrowski, Bartosz; Decowski, M. P.; Despet, M.; Fita, P.; Fitch, J.; Friedl, M.; Gałuszka, K.; Ganz, R.; Garcia, E. Oliver; George, N.; Godlewski, J.; Gomes, C.; Griesmayer, E.; Gulbrandsen, K.; Gushue, S.; Halik, J.; Halliwell, C.; Haridas, P.; Hayes, A. B.; Heintzelman, G. A.; Henderson, C.; Hollis, R. S.; Hołyński, R.; Hofman, D. J.; Holzman, B.; Johnson, E.; Kane, J. L.; Katzy, J.; Kita, W.; Kotuła, J.; Kraner, H.W.; Kucewicz, W.; Kulinich, P.; Law, C.; Lemler, M.; Ligocki, J.; Lin, W.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A. C.; Mülmenstädt, J.; Neal, M. J.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I.C; Patel, Mehul V.; Pernegger, H.; Pleško, M.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Ross, D. K.; Rosenberg, L.; Ryan, J. J.; Sanzgiri, A.; Sarin, P.; Sawicki, P.; Scaduto, J.; Shea, J.; Sinacore, J.; Skulski, W.; Steadman, S. G.; Stephans, G. S. F.; Steinberg, P.; Straczek, A.; Stodulski, M.; Strek, M.; Stopa, Z.; Sukhanov, A.; Surowiecka, K.; Tang, J. L.; Teng, R.; Trzupek, A.; Vale, C.; Nieuwenhuizen, G. J. van; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B. K.; Woźniak, K. W.; Wuosmaa, A. H.; Wysłouch, B.; Zalewski, K.; Żychowski, P.

doi:10.1016/s0168-9002(02)01959-9

Cited by 100 publications

(50 citation statements)

References 16 publications

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“…A detailed description of the PHOBOS detector can be found in [ 2]. The main components of the apparatus are a two-arm high-resolution magnetic spectrometer near midrapidity and a nearly 4-π charged particle multiplicity detector covering |η| < 5.4.…”

Section: The Phobos Experimentsmentioning

confidence: 99%

New results from the PHOBOS experiment

Roland

2006

Nuclear Physics A

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Over the past five years, PHOBOS has collected data on proton-proton, deuterongold, Au+Au and Cu+Cu collisions, covering a wide range of collision energy, collision centrality and system size. Using these data, we have identified scaling features that are common for all types of high-energy collisions, as well as collective effects that are unique to the conditions created in collisions of relativistic nuclei. In this paper, we will focus on recent results obtained for collisions of Cu nuclei. Both in terms of universal features of particle production, and in the development of truly collective effects, the results for Cu nuclei confirm and extend our present understanding of nuclear collisions at the highest energies. In addition, we will describe recent unique results on multiplicity fluctuations and particle production at very low transverse momenta.

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Section: The Phobos Experimentsmentioning

confidence: 99%

New results from the PHOBOS experiment

Roland

2006

Nuclear Physics A

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“…To obtain a better resolution along the beam axis (z), a complementary method based on all possible two-point straight tracks is used. Straight line trajectories are assumed as the magnetic field in the region of the Vertex detector or the inner six planes of the Spectrometer (used in the vertex reconstruction) is negligible [9]. If the two-point track, formed from the Vertex detector and the first two silicon layers of the Spectrometer, passes close to the (x, y) orbit position of the beam, then the z-coordinate at the orbit position is considered a candidate for the collision vertex.…”

mentioning

confidence: 99%

“…[1,13]. The midrapidity charged-particle pseudorapidity density measurement in this Rapid Communication is based on hit patterns in the dual-plane Vertex silicon detector [9]. Two reconstructed hits in either the top or bottom pair of planes form a "tracklet."…”

mentioning

confidence: 99%

Scaling properties in bulk andpT-dependent particle production near midrapidity in relativistic heavy ion collisions

Alver¹,

Back²,

Baker³

et al. 2009

Phys. Rev. C

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The centrality dependence of the midrapidity charged-particle multiplicity density (|η| < 1) is presented for Au + Au and Cu + Cu collisions at RHIC over a broad range of collision energies. The multiplicity measured in the Cu + Cu system is found to be similar to that measured in the Au + Au system, for an equivalent N part , with the observed factorization in energy and centrality still persistent in the smaller Cu + Cu system. The extent of the similarities observed for bulk particle production is tested by a comparative analysis of the inclusive transverse momentum distributions for Au + Au and Cu + Cu collisions near midrapidity. It is found that, within the uncertainties of the data, the ratio of yields between the various energies for both Au + Au and Cu + Cu systems are similar and constant with centrality, both in the bulk yields and as a function of p T , up to at least 4 GeV/c. The effects of multiple nucleon collisions that strongly increase with centrality and energy appear to only play a minor role in bulk and intermediate transverse momentum particle production. The experimental program at the Relativistic Heavy-Ion Collider (RHIC) at Brookhaven National Laboratory has opened a new era in the study of QCD matter. Measurements of the midrapidity density of charged particles have, from the start of the RHIC program, provided an estimate of the energy density created in these collisions as well as an important baseline against which to test core features of particle production in models. The wealth of data on bulk charged-particle production collected in the first five years of RHIC operations has revealed the presence of various features in the data that appear to be universal, including a factorization of the chargedparticle production into two components, one that depends on collision energy, or √ s NN , and the other on the centrality of the colliding heavy ions [1]. The energy dependence of the midrapidity charged-particle density appears to be consistent with a logarithmic rise with √ s NN [2]. This logarithmic dependence resembles that in elementary p + p and e + + e − collisions [3] and was not a priori expected for relativistic heavy ion collisions. In particular, initial expectations of a large increase in particle production with collision energy for central heavy ion collisions from multiple binary nucleon scatterings and the increased formation of mini-jets were not realized. Further studies revealed a relatively weak dependence of the produced midrapidity charged-particle multiplicity density per participant pair on the collision centrality. From a two-component picture [4], the part of the multiplicity that scales with the number of binary collisions (N coll ) contributes at the level of only ≈13%, across all energies studied so far at RHIC [5,6].This Rapid Communication reports results from RHIC for the midrapidity charged-particle density in Cu + Cu collisions at √ s NN = 22.4, 62.4, and 200 GeV as a function of centrality. The data correspond to the top 50% of the total inelastic c...

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“…For some of the events with the real vertex outside this acceptance range a false vertex is found, especially at positive z. There are more background hits registered, mostly from secondary particles produced in the coils and the yoke of the PHOBOS magnet [1]. Such events can be rejected by restricting the vertex range using information from the trigger counters.…”

Section: Efficiency and Accuracy Of The Vertex Reconstruction Algorithmmentioning

confidence: 99%

“…In RHIC experiments, the vertex positions are distributed along the beam axis in a range as large as 2 m about the nominal center of the apparatus, with a transverse spread smaller than 1 mm. The PHOBOS detector [1] includes several subsystems which are used also for determinations of the vertex position: the trigger system, the two arm multi-layer spectrometer for measuring charged particles trajectories, the vertex detector consisting of two layers of silicon sensors and the multiplicity detector measuring charged particles. Most of the active elements of the PHOBOS detector employ silicon sensors described in detail in [2].…”

Section: Introductionmentioning

confidence: 99%

Vertex reconstruction using a single layer silicon detector

Garcia

Hollis

Olszewski

et al. 2007

Nuclear Instruments and Methods in Physics Research Section A:

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Typical vertex finding algorithms use reconstructed tracks, registered in a multilayer detector, which directly point to the common point of origin. A detector with a single layer of silicon sensors registers the passage of primary particles only in one place. Nevertheless, the information available from these hits can also be used to estimate the vertex position, when the geometrical properties of silicon sensors and the measured ionization energy losses of the particles are fully exploited. In this paper the algorithm used for this purpose in the PHOBOS experiment is described. The vertex reconstruction performance is studied using simulations and compared with results obtained from real data. The very large acceptance of a single-layered multiplicity detector permits vertex reconstruction for low multiplicity events where other methods, using small acceptance subdetectors, fail because of insufficient number of registered primary tracks.

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The PHOBOS detector at RHIC

Cited by 100 publications

References 16 publications

New results from the PHOBOS experiment

New results from the PHOBOS experiment

Scaling properties in bulk andpT-dependent particle production near midrapidity in relativistic heavy ion collisions

Vertex reconstruction using a single layer silicon detector

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