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arXiv · 1505.06766

Nucleon-Gold Collisions at 200 AGeV Using Tagged d+Au Interactions in PHOBOS

B. B. Back·M. D. Baker·M. Ballintijn·D. S. Barton·B. Becker·R. R. Betts·A. A. Bickley·R. Bindel·W. Busza·A. Carroll·M. P. Decowski·E. García·T. Gburek·N. George·K. Gulbrandsen·S. Gushue·C. Halliwell·J. Hamblen·A. S. Harrington·C. Henderson·D. J. Hofman·R. S. Hollis·R. Hołyński·B. Holzman·A. Iordanova·E. Johnson·J. L. Kane·N. Khan·P. Kulinich·C. M. Kuo·J. W. Lee·W. T. Lin·S. Manly·A. C. Mignerey·R. Nouicer·A. Olszewski·R. Pak·I. C. Park·H. Pernegger·C. Reed·C. Roland·G. Roland·J. Sagerer·P. Sarin·I. Sedykh·W. Skulski·C. E. Smith·P. Steinberg·G. S. F. Stephans·A. Sukhanov·M. B. Tonjes·A. Trzupek·C. Vale·G. J. van Nieuwenhuizen·R. Verdier·G. I. Veres·F. L. H. Wolfs·B. Wosiek·K. Woźniak·B. Wysłouch·J. Zhang
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Abstract

Forward calorimetry in the PHOBOS detector has been used to study charged hadron production in d+Au, p+Au and n+Au collisions at sqrt(s_nn) = 200 GeV. The forward proton calorimeter detectors are described and a procedure for determining collision centrality with these detectors is detailed. The deposition of energy by deuteron spectator nucleons in the forward calorimeters is used to identify p+Au and n+Au collisions in the data. A weighted combination of the yield of p+Au and n+Au is constructed to build a reference for Au+Au collisions that better matches the isospin composition of the gold nucleus. The p_T and centrality dependence of the yield of this improved reference system is found to match that of d+Au. The shape of the charged particle transverse momentum distribution is observed to extrapolate smoothly from pbar+p to central d+Au as a function of the charged particle pseudorapidity density. The asymmetry of positively- and negatively-charged hadron production in p+Au is compared to that of n+Au. No significant asymmetry is observed at mid-rapidity. These studies augment recent results from experiments at the LHC and RHIC facilities to give a more complete description of particle production in p+A and d+A collisions, essential for the understanding the medium produced in high energy nucleus-nucleus collisions.

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B. B. Back, M. D. Baker, M. Ballintijn, D. S. Barton, B. Becker, R. R. Betts, A. A. Bickley, R. Bindel, W. Busza, A. Carroll, M. P. Decowski, E. García, T. Gburek, N. George, K. Gulbrandsen, S. Gushue, C. Halliwell, J. Hamblen, A. S. Harrington, C. Henderson, D. J. Hofman, R. S. Hollis, R. Hołyński, B. Holzman, A. Iordanova, E. Johnson, J. L. Kane, N. Khan, P. Kulinich, C. M. Kuo, J. W. Lee, W. T. Lin, S. Manly, A. C. Mignerey, R. Nouicer, A. Olszewski, R. Pak, I. C. Park, H. Pernegger, C. Reed, C. Roland, G. Roland, J. Sagerer, P. Sarin, I. Sedykh, W. Skulski, C. E. Smith, P. Steinberg, G. S. F. Stephans, A. Sukhanov, M. B. Tonjes, A. Trzupek, C. Vale, G. J. van Nieuwenhuizen, R. Verdier, G. I. Veres, F. L. H. Wolfs, B. Wosiek, K. Woźniak, B. Wysłouch, J. Zhang. 2015-05-25. Nucleon-Gold Collisions at 200 AGeV Using Tagged d+Au Interactions in PHOBOS. https://doi.org/10.1103/physrevc.92.034915

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