Participant and spectator scaling of spectator fragments in Au + Au and Cu + Cu collisions at √sNN = 19.6 and 22.4 GeV

Participant and spectator scaling of spectator fragments in Au + Au and Cu + Cu collisions at √sNN = 19.6 and 22.4 GeV

Spectator fragments resulting from relativistic heavy ion collisions, consisting of single protons and neutrons along with groups of stable nuclear fragments up to nitrogen (Z=7), are measured in PHOBOS. These fragments are observed in Au+Au (√sNN =19.6GeV) and Cu+Cu (22.4 GeV) collisions at high ps...

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Bibliographic Details
Main Authors: Back, B. B., Baker, M. D., Barton, D. S., Betts, R. R., Bickley, A. A., Bindel, R., Budzanowski, A., Carroll, A., Chai, Z., Chetluru, V., García, E., Gburek, T., George, N., Gushue, S., Halliwell, C., Hamblen, J., Harnarine, I., Heintzelman, G. A., Henderson, C., Hofman, D. J., Hollis, R. S., Hołyński, R., Holzman, B., Iordanova, A., Johnson, E., Khan, N., Kucewicz, W., Kuo, C. M., Lin, W. T., Manly, S., McLeod, D., Mignerey, A. C., Nouicer, R., Olszewski, A., Pak, R., Park, I. C., Remsberg, L. P., Reuter, M., Richardson, E., Sagerer, J., Sawicki, P., Sedykh, I., Skulski, W., Smith, C. E., Stankiewicz, M. A., Steinberg, P., Sukhanov, A., Szostak, A., Tang, J.-L., Tonjes, M. B., Trzupek, A., Walters, P., Willhelm, D., Wolfs, F. L. H., Wosiek, B., Woźniak, K., Wuosmaa, A. H., Wyngaardt, S., Alver, Burak Han, Busza, Wit, Katzy, J., Li, W., Loizides, Constantinos, Pernegger, H., Roland, Christof E, Roland, Gunther M, Rosenberg, L., Stephans, George S. F., van Nieuwenhuizen, Gerrit J, Vaurynovich, Siarhei S., Verdier, Robin, Veres, Gabor, Wenger, Edward Allen, Wyslouch, Boleslaw, Ballintijn, Maarten, Decowski, Michael P., Gulbrandsen, K., Kane, J. L., Kulinich, Piotr, Reed, C., Sarin, P., Vale, C.
Other Authors: Massachusetts Institute of Technology. Department of Physics
Format: Article
Language:English
Published: American Physical Society 2017
Online Access:http://hdl.handle.net/1721.1/109804
https://orcid.org/0000-0002-3831-9071
https://orcid.org/0000-0001-8983-2169
https://orcid.org/0000-0003-3106-4894
https://orcid.org/0000-0002-4918-5128
https://orcid.org/0000-0003-3681-0649
Description
Summary:Spectator fragments resulting from relativistic heavy ion collisions, consisting of single protons and neutrons along with groups of stable nuclear fragments up to nitrogen (Z=7), are measured in PHOBOS. These fragments are observed in Au+Au (√sNN =19.6GeV) and Cu+Cu (22.4 GeV) collisions at high pseudorapidity (η). The dominant multiply-charged fragment is the tightly bound helium (α), with lithium, beryllium, and boron all clearly seen as a function of collision centrality and pseudorapidity. We observe that in Cu+Cu collisions, it becomes much more favorable for the α fragments to be released than lithium. The yields of fragments approximately scale with the number of spectator nucleons, independent of the colliding ion. The shapes of the pseudorapidity distributions of fragments indicate that the average deflection of the fragments away from the beam direction increases for more central collisions. A detailed comparison of the shapes for α and lithium fragments indicates that the centrality dependence of the deflections favors a scaling with the number of participants in the collision.

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