Search

Your search keyword '"D. Willhelm"' showing total 23 results
Start Over Author "D. Willhelm"
23 results on '"D. Willhelm"'

1. Participant and spectator scaling of spectator fragments in Au + Au and Cu + Cu collisions atsNN=19.6and 22.4 GeV

Author

I. Sedykh, Judith Katzy, P. Steinberg, A. S. Carroll, J. Sagerer, T. Gburek, Alice Mignerey, R. Bindel, R. Verdier, A. H. Wuosmaa, M. P. Decowski, R. S. Hollis, Christophe Pol A Roland, Adam Trzupek, S. Gushue, R. Holynski, P. Walters, J. L. Kane, George S. F. Stephans, S. Manly, G. J. van Nieuwenhuizen, Russell Richard Betts, Conor Henderson, G. A. Heintzelman, C. Halliwell, P. Sarin, Gunther Roland, K. Gulbrandsen, C. Loizides, N. Khan, I. Harnarine, W. Kucewicz, E. Richardson, N. George, E. García, P. Kulinich, W. Skulski, B. B. Back, Burt Holzman, A. Iordanova, A. Szostak, Bolek Wyslouch, Inkyu Park, S. S. Vaurynovich, Barbara Wosiek, L.J. Rosenberg, Z. Chai, Gabor Istvan Veres, Jau Tang, B. Alver, E. Johnson, Krzysztof Woźniak, Heinz Pernegger, A. Budzanowski, A. Sukhanov, Chia-Ming Kuo, Wit Busza, R. Pak, M. Ballintijn, J. Hamblen, W. T. Lin, Rachid Nouicer, D. McLeod, M. A. Stankiewicz, M. Reuter, Andrzej Olszewski, M. D. Baker, L. P. Remsberg, M. B. Tonjes, V. Chetluru, P. Sawicki, C. E. Smith, D. Willhelm, Wei Li, F. L. H. Wolfs, S. M. Wyngaardt, Edward Allen Wenger, D. S. Barton, A. A. Bickley, C. Reed, D. J. Hofman, and C. Vale

Subjects
Physics, 010308 nuclear & particles physics, chemistry.chemical_element, 01 natural sciences, Ion, Nuclear physics, chemistry, Pseudorapidity, 0103 physical sciences, Neutron, Atomic physics, Impact parameter, Nuclear Experiment, 010306 general physics, Relativistic Heavy Ion Collider, Nucleon, Glauber, Helium
Abstract

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 $(\sqrt{{s}_{{}_{NN}}}=19.6\phantom{\rule{0.16em}{0ex}}\mathrm{GeV})$ and Cu+Cu (22.4 GeV) collisions at high pseudorapidity $(\ensuremath{\eta})$. The dominant multiply-charged fragment is the tightly bound helium $(\ensuremath{\alpha})$, 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 $\ensuremath{\alpha}$ 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 $\ensuremath{\alpha}$ and lithium fragments indicates that the centrality dependence of the deflections favors a scaling with the number of participants in the collision.

Published
2016

2. Recent results from PHOBOS on particle production at high p T

Author

D. Willhelm, V. Chetluru, Wei Li, M. P. Decowski, R. S. Hollis, Alice Mignerey, P. Kulinich, R. Bindel, Christof Roland, George Stephans, J. L. Kane, S. Manly, R. Pak, A. Szostak, Bolek Wyslouch, David Jonathan Hofman, S. M. Wyngaardt, C. Halliwell, Burt Holzman, A. Iordanova, H. Seals, Chia-Ming Kuo, C. Vale, T. Gburek, D. S. Barton, E. Richardson, M. D. Baker, R. Holynski, S. S. Vaurynovich, A. A. Bickley, Marguerite Tonjes, M. Ballintijn, B. B. Back, J. Sagerer, K. Gulbrandsen, C. Loizides, Gabor Istvan Veres, Peter Steinberg, J. Hamblen, Andrzej Olszewski, C. Reed, I. Sedykh, Willis Lin, M. A. Stankiewicz, E. Johnson, Barbara Wosiek, B. Alver, E. García, Gunther Roland, G. Van Nieuwenhuizen, C. E. Smith, I. Harnarine, A. S. Carroll, R. Verdier, Rachid Nouicer, P. Walters, Russell Richard Betts, Conor Henderson, Adam Trzupek, F. L. H. Wolfs, Z. Chai, N. Khan, Krzysztof Woźniak, Edward Allen Wenger, A. Sukhanov, M. Hauer, Wit Busza, and N. George

Subjects
Nuclear reaction, Physics, Particle physics, Range (particle radiation), Physics and Astronomy (miscellaneous), 010308 nuclear & particles physics, Elementary particle, Parton, 01 natural sciences, Charged particle, Nuclear physics, Pseudorapidity, 0103 physical sciences, Rapidity, Nuclear Experiment, 010306 general physics, Relativistic Heavy Ion Collider, Engineering (miscellaneous)
Abstract

A selection of experimental results from the PHOBOS Collaboration relevant for probing high-energy nuclear collisions with high transverse momentum particles is presented. The inclusive yields of charged particles and comparisons between nuclear and elementary collisions already reveal a large amount of parton energy loss in the hot and dense medium created in heavy ion collisions. Remarkable scaling and factorization features are observed, unifying the data taken at various collision energies, centralities and nuclear sizes. To further analyze the nature of the energy loss, a measurement of pseudorapidity (Δη) and azimuthal angle (Δφ) correlations between high transverse momentum charged hadrons (pT>2.5 GeV/c) and all associated charged particles is presented at both short-range (small Δη) and long-range (large Δη) over a continuous detector acceptance covering −4

Published
2009

3. Particle production in nuclear collisions over a broad centrality range from the PHOBOS experiment

Author

Inkyu Park, R. Ho⌈yński, N. George, F. L. H. Wolfs, K. Gulbrandsen, C. Loizides, M. P. Decowski, D. Willhelm, P. Sawicki, A. Szostak, P. Kulinich, Bolek Wyslouch, W. Kucewicz, Burt Holzman, Chia-Ming Kuo, Andrzej Olszewski, Edward Allen Wenger, L.J. Rosenberg, R. S. Hollis, W. Skulski, A. Budzanowski, V. Chetluru, E. Richardson, M. Ballintijn, N. Khan, Wei Li, Christof Roland, David Jonathan Hofman, C. E. Smith, Russell Richard Betts, Conor Henderson, Alice Mignerey, J. L. Kane, I. Sedykh, T. Gburek, A. Iordanova, S. Manly, M. Reuter, M. D. Baker, George Stephans, J. Hamblen, R. Bindel, C. Vale, G. Van Nieuwenhuizen, S. Gushue, P. Walters, B. B. Back, Z. Chai, Rachid Nouicer, Adam Trzupek, M. A. Stankiewicz, Marguerite Tonjes, Krzysztof Woźniak, G. A. Heintzelman, Willis Lin, E. García, C. Reed, A. Sukhanov, L. P. Remsberg, S. S. Vaurynovich, Wit Busza, R. Pak, A. H. Wuosmaa, Gunther Roland, Barbara Wosiek, I. Harnarine, B. Alver, P. Sarin, A. S. Carroll, R. Verdier, C. Halliwell, S. M. Wyngaardt, Gabor Istvan Veres, Peter Steinberg, D. S. Barton, A. A. Bickley, E. Johnson, J. Sagerer, and Jaw-Luen Tang

Subjects
Physics, Nuclear physics, Factorization, Pseudorapidity, General Physics and Astronomy, Heavy ion, Atomic physics, Multiplicity (chemistry), Nuclear Experiment, Centrality, Collision, Scaling, Charged particle
Abstract

The PHOBOS collaboration has studied the pseudorapidity and transverse momentum distributions of charged particles produced in heavy ion collisions. Results from Au+Au collisions at various center-of-mass energies and over a broad range of centrality are presented here. The data are compared to Cu+Cu, p+p and d+Au collisions at corresponding energies and centralities. The data are found to exhibit simple scaling properties such as the observed factorization of collision energy and geometry dependences. The presented data help us distinguish between models of particle production in relativistic heavy ion collisions.

Published
2006

5. Properties of the matter created in heavy ion collisions – results from the PHOBOS experiment

Author

D. J. Hofman, C. Vale, Gunther Roland, P. Steinberg, C. Reed, R. Holynski, P. Walters, A. Sukhanov, F. L. H. Wolfs, H. Seals, M. Hauer, I. Harnarine, M. P. Decowski, S. Manly, A. Szostak, K. Gulbrandsen, C. Loizides, P. Kulinich, Wit Busza, R. Pak, Alice Mignerey, Bolek Wyslouch, R. Bindel, I. Sedykh, S. S. Vaurynovich, C. E. Smith, E. Richardson, N. George, A. Iordanova, Z. Chai, G. J. van Nieuwenhuizen, Stankiewicz, George S. F. Stephans, T. Gburek, R. S. Hollis, N. Khan, Adam Trzupek, A. S. Carroll, J. Sagerer, E. García, Gabor Istvan Veres, Burt Holzman, E. Johnson, Christophe Pol A Roland, Chia-Ming Kuo, Edward Allen Wenger, Krzysztof Wozniak, Wei Li, M. Ballintijn, Barbara Wosiek, J. Hamblen, M. B. Tonjes, V. Chetluru, Russell Richard Betts, Conor Henderson, B. Alver, C. Halliwell, D. Willhelm, W. T. Lin, Rachid Nouicer, Andrzej Olszewski, Baker, J. L. Kane, B. B. Back, R. Verdier, S. M. Wyngaardt, D. S. Barton, and A. A. Bickley

Subjects
Nuclear physics, Physics, Heavy ion, Atomic physics, Nuclear Experiment
Abstract

In the collisions of ultrarelativistic heavy ions the energy of the nuclei is released in a small volume leading to the creation of a hot and dense nuclear matter. The study of the particles produced from it gives the information on the conditions in the early stage of the collision and the evolution of the system. The PHOBOS experiment provides unique data on the particle production in the almost full phase space and down to very small transverse momenta. This overview shortly presents the most important features of the nucleus-nucleus collisions observed by the PHOBOS experiment, but concentrates on the most recent studies. The extensive analyses of charged particles production are based on the multiplicity measurements in a very wide pseudorapidity range and reveal strong short and long range correlations. The correlations with a high p T trigger particle extends at least 4 units in pseudorapidity, while two-particle correlations suggest production of particles in large and wide clusters. © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence.

Published
2010

6. System size dependence of cluster properties from two-particle angular correlations inCu+CuandAu+Aucollisions atsNN=200GeV

Author

B. Alver, B. B. Back, M. D. Baker, M. Ballintijn, D. S. Barton, R. R. Betts, R. Bindel, W. Busza, Z. Chai, V. Chetluru, E. García, T. Gburek, K. Gulbrandsen, J. Hamblen, I. Harnarine, C. Henderson, D. J. Hofman, R. S. Hollis, R. Hołyński, B. Holzman, A. Iordanova, J. L. Kane, P. Kulinich, C. M. Kuo, W. Li, W. T. Lin, C. Loizides, S. Manly, A. C. Mignerey, R. Nouicer, A. Olszewski, R. Pak, C. Reed, E. Richardson, C. Roland, G. Roland, J. Sagerer, I. Sedykh, C. E. Smith, M. A. Stankiewicz, P. Steinberg, G. S. F. Stephans, A. Sukhanov, A. Szostak, M. B. Tonjes, A. Trzupek, G. J. van Nieuwenhuizen, S. S. Vaurynovich, R. Verdier, G. I. Veres, P. Walters, E. Wenger, D. Willhelm, F. L. H. Wolfs, B. Wosiek, K. Woźniak, S. Wyngaardt, and B. Wysłouch

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Context (language use), 01 natural sciences, Charged particle, Baryon, Pseudorapidity, 0103 physical sciences, Cluster (physics), Impact parameter, Atomic physics, Nuclear Experiment, 010306 general physics, Relativistic Heavy Ion Collider, Nucleon
Abstract

We present results on two-particle angular correlations in Cu+Cu and Au+Au collisions at a center-of-mass energy per nucleon pair of 200 GeV over a broad range of pseudorapidity (eta) and azimuthal angle (phi) values as a function of collision centrality. The PHOBOS detector at the Relativistic Heavy Ion Collider has a uniquely large angular coverage for inclusive charged particles, which allows for the study of correlations on both long- and short-range scales. A complex two-dimensional correlation structure in {Delta}{eta} and {Delta}{phi} emerges, which is interpreted in the context of a cluster model. The effective cluster size and decay width are extracted from the two-particle pseudorapidity correlation functions. The effective cluster size found in semicentral Cu+Cu and Au+Au collisions is comparable to that found in proton-proton collisions but a nontrivial decrease in size with increasing centrality is observed. Moreover, a comparison of results from Cu+Cu versus Au+Au collisions shows an interesting scaling of the effective cluster size with the measured fraction of total cross section (which is related to the ratio of the impact parameter to the nuclear radius, b/2R), suggesting a geometric origin. Further analysis for pairs from restricted azimuthal regions shows that the effective cluster size at {Delta}{phi}{approx}180 deg.more » drops more rapidly toward central collisions than the size at {Delta}{phi}{approx}0 deg. The effect of limited {eta} acceptance on the cluster parameters is also addressed, and a correction is applied to present cluster parameters for full {eta} coverage, leading to much larger effective cluster sizes and widths than previously noted in the literature. These results should provide insight into the hot and dense medium created in heavy ion collisions.« less

Published
2010

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

Author

I. Sedykh, F. L. H. Wolfs, Wei Li, T. Gburek, A. Iordanova, Z. Chai, Alice Mignerey, R. Bindel, Adam Trzupek, Burt Holzman, Krzysztof Woźniak, A. Szostak, Bolek Wyslouch, Russell Richard Betts, Conor Henderson, R. Holynski, P. Walters, George S. F. Stephans, Gunther Roland, Edward Allen Wenger, G. J. van Nieuwenhuizen, A. Sukhanov, Barbara Wosiek, M. D. Baker, I. Harnarine, D. Willhelm, P. Kulinich, S. M. Wyngaardt, Wit Busza, R. Pak, B. Alver, Gabor Istvan Veres, S. S. Vaurynovich, Marguerite Tonjes, D. S. Barton, C. Reed, D. J. Hofman, M. A. Stankiewicz, Rachid Nouicer, Andrzej Olszewski, J. Sagerer, E. García, K. Gulbrandsen, C. Loizides, P. Steinberg, E. Richardson, Christophe Pol A Roland, Chia-Ming Kuo, M. Ballintijn, J. Hamblen, R. S. Hollis, C. E. Smith, R. Verdier, B. B. Back, Willis Lin, J. L. Kane, S. Manly, and V. Chetluru

Subjects
Physics, Nuclear and High Energy Physics, Quantitative Biology::Neurons and Cognition, 010308 nuclear & particles physics, chemistry.chemical_element, 01 natural sciences, Copper, Charged particle, Nuclear physics, Factorization, chemistry, 0103 physical sciences, Transverse momentum, Heavy ion, Multiplicity (chemistry), Nuclear Experiment, 010306 general physics, Nucleon, Scaling
Abstract

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 Npart, 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 pT ,u p 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.

Published
2009

9. Identified charged antiparticle to particle ratios near midrapidity in Cu+Cu collisions atsNN=62.4and 200 GeV

Author

R. Bindel, A. Sukhanov, Wit Busza, R. Pak, F. L. H. Wolfs, C. E. Smith, K. Gulbrandsen, C. Loizides, G. J. van Nieuwenhuizen, George S. F. Stephans, Adam Trzupek, Barbara Wosiek, Wei Li, R. S. Hollis, B. Alver, Burt Holzman, W. T. Lin, C. Reed, Rachid Nouicer, Chia-Ming Kuo, A. Szostak, Bolek Wyslouch, Andrzej Olszewski, R. Verdier, M. Ballintijn, Edward Allen Wenger, M. B. Tonjes, Russell Richard Betts, Conor Henderson, V. Chetluru, D. J. Hofman, Christophe Pol A Roland, J. Hamblen, S. M. Wyngaardt, T. Gburek, D. S. Barton, D. Willhelm, M. D. Baker, E. García, M. A. Stankiewicz, B. B. Back, E. Richardson, J. L. Kane, S. Manly, J. Sagerer, Z. Chai, Krzysztof Woźniak, Gunther Roland, I. Harnarine, P. Kulinich, S. S. Vaurynovich, R. Holynski, P. Walters, A. Iordanova, I. Sedykh, P. Steinberg, Gabor Istvan Veres, and Alice Mignerey

Subjects
Physics, Nuclear and High Energy Physics, Antiparticle, 010308 nuclear & particles physics, chemistry.chemical_element, 01 natural sciences, Copper, Nuclear physics, Pion, chemistry, 0103 physical sciences, Particle, High Energy Physics::Experiment, Atomic physics, Nuclear Experiment, 010306 general physics, Energy (signal processing)
Abstract

Antiparticle to particle ratios for identified protons, kaons, and pions at {radical}(s{sub NN})=62.4 and 200 GeV in Cu+Cu collisions are presented as a function of centrality for the midrapidity region of 0.2 / ratio at {approx_equal}0.51 GeV/c, we observe an average value of 0.50{+-}0.003{sub (stat)}{+-}0.04{sub (syst)} and 0.77{+-}0.008{sub (stat)}{+-}0.05{sub (syst)} for the 10% most central collisions of 62.4 and 200 GeV Cu+Cu, respectively. The values for all three particle species measured at {radical}(s{sub NN})=200 GeV are in agreement within systematic uncertainties with that seen in both heavier and lighter systems measured at the same RHIC energy. This indicates that system size does not appear to play a strong role in determining the midrapidity chemical freeze-out properties affecting the antiparticle to particle ratios of the three most abundant particle species produced in these collisions.

Published
2008

10. System Size, Energy and Centrality Dependence of Pseudorapidity Distributions of Charged Particles in Relativistic Heavy Ion Collisions

Author

C. E. Smith, Burt Holzman, J. L. Kane, Adam Trzupek, S. Manly, Russell Richard Betts, Conor Henderson, R. S. Hollis, Chia-Ming Kuo, Gunther Roland, I. Harnarine, I. Sedykh, P. Kulinich, M. Ballintijn, A. Szostak, K. Gulbrandsen, C. Loizides, M. A. Stankiewicz, Alice Mignerey, R. Bindel, R. Verdier, Barbara Wosiek, S. S. Vaurynovich, George S. F. Stephans, B. B. Back, Willis Lin, T. Gburek, A. Sukhanov, Chetluru, D. S. Barton, Christof Roland, Gabor Istvan Veres, Wit Busza, R. Pak, Z. Chai, Krzysztof Woźniak, Wei Li, van Nieuwenhuizen Gj, D. Willhelm, S. M. Wyngaardt, Hamblen J, E. García, D. J. Hofman, Marguerite Tonjes, Boleslaw Wyslouch, C. Reed, J. Sagerer, P. Steinberg, Rachid Nouicer, Alver B, Andrzej Olszewski, Baker, E. Richardson, R. Holynski, P. Walters, A. Iordanova, F. L. H. Wolfs, and Edward Allen Wenger

Subjects
Nuclear reaction, Physics, Range (particle radiation), Quantitative Biology::Neurons and Cognition, 010308 nuclear & particles physics, Hadron, FOS: Physical sciences, General Physics and Astronomy, Elementary particle, 01 natural sciences, Charged particle, Nuclear physics, Baryon, Pseudorapidity, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Atomic physics, 010306 general physics, Nucleon, Nuclear Experiment
Abstract

We present the first measurements of the pseudorapidity distribution of primary charged particles in Cu+Cu collisions as a function of collision centrality and energy, \sqrtsnn = 22.4, 62.4 and 200 GeV, over a wide range of pseudorapidity, using the PHOBOS detector. Making a global comparison of Cu+Cu and Au+Au results, we find that the total number of produced charged particles and the rough shape (height and width) of the pseudorapidity distributions are determined by the number of nucleon participants. More detailed studies reveal that a more precise matching of the shape of the Cu+Cu and Au+Au pseudorapidity distributions over the full range of pseudorapidity occurs for the same Npart/2A value rather than the same Npart value. In other words, it is the collision geometry rather than just the number of nucleon participants that drives the detailed shape of the pseudorapidity distribution and its centrality dependence at RHIC energies., Submitted to Physical Review Letters

Published
2007

11. Cluster properties from two-particle angular correlations inp+pcollisions ats=200and 410 GeV

Author

Adam Trzupek, M. A. Stankiewicz, Alice Mignerey, Marguerite Tonjes, C. Reed, J. Sagerer, R. S. Hollis, R. Bindel, K. Gulbrandsen, D. J. Hofman, P. Steinberg, Bolek Wyslouch, C. Lozides, Russell Richard Betts, Conor Henderson, E. García, Barbara Wosiek, S. S. Vaurynovich, I. Sedykh, Burt Holzman, A. Szopstak, B. Alver, Chia-Ming Kuo, Gabor Istvan Veres, Edward Allen Wenger, J. L. Kane, S. Manly, Wei Li, M. D. Baker, M. Ballintijn, R. Verier, F. L. H. Wolfs, J. Hamblen, G. J. van Nieuwenhuizen, W. T. Lin, G. S. F. Stephens, Rachid Nouicer, Gunther Roland, B. B. Back, Andrzej Olszewski, I. Harnarine, P. Kulinich, E. Richardson, T. Gburek, D. Willhelm, S. M. Wyngaardt, A. Iordanova, Christophe Pol A Roland, R. Holynski, P. Walters, D. S. Barton, V. Chetluru, C. E. Smith, A. Sukhanov, Wit Busza, R. Pak, Z. Chai, and Krzysztof Woźniak

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, 010308 nuclear & particles physics, Nuclear Theory, Context (language use), 01 natural sciences, Charged particle, Nuclear physics, Correlation function (statistical mechanics), Pseudorapidity, 0103 physical sciences, Cluster size, Cluster (physics), Physics::Accelerator Physics, Particle, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Relativistic Heavy Ion Collider
Abstract

We present results on two-particle angular correlations in proton-proton collisions at center-of-mass energies of 200 and 410 GeV. The PHOBOS experiment at the BNL Relativistic Heavy Ion Collider has a uniquely large coverage for charged particles, giving the opportunity to explore the correlations at both short- and long-range scales. At both energies, a complex two-dimensional correlation structure in $\ensuremath{\Delta}\ensuremath{\eta}$ and $\ensuremath{\Delta}\ensuremath{\phi}$ is observed. In the context of an independent cluster model of short-range correlations, the cluster size and its decay width are extracted from the two-particle pseudorapidity correlation function and compared with previous measurements in proton-proton and proton-antiproton collisions, as well as PYTHIA and HIJING predictions.

Published
2007

12. Elliptic flow fluctuations at PHOBOS

Author

I. Sedykh, Andrzej Olszewski, Kinga Anna Wozniak, N. George, Burt Holzman, A. S. Carroll, J. Sagerer, M. P. Decowski, Barbara Wosiek, Edward Allen Wenger, Gunther Roland, G.J. vanNieuwenhuizen, Russell Richard Betts, Conor Henderson, E. García, B. Alver, R. S. Hollis, I. Harnarine, P. Kulinich, A. Szostak, Bolek Wyslouch, W. T. Lin, S. S. Vaurynovich, F. L. H. Wolfs, K. Gulbrandsen, C. E. Smith, T. Gburek, Wei Li, C. Halliwell, George Stephans, Z. Chai, M. B. Tonjes, V. Chetluru, N. Khan, M. Ballintijn, H. Seals, J. Hamblen, S. Manly, B. B. Back, A. Sukhanov, M. Hauer, Rachid Nouicer, Adam Trzupek, Wit Busza, R. Pak, D. S. Barton, R. Verdier, A. A. Bickley, J. L. Kane, Constantin Loizides, S. M. Wyngaardt, P. Steinberg, Gabor Istvan Veres, E. Johnson, Alice Mignerey, R. Bindel, D. Willhelm, Chih-Yu Kuo, M. A. Stankiewicz, M. D. Baker, R. Holynski, P. Walters, C. Reed, A. Iordanova, E. Richardson, D. J. Hofman, Christophe Pol A Roland, and C. Vale

Subjects
Physics, Elliptic flow, Mechanics
Published
2007

13. System Size and Centrality Dependence of Charged Hadron Transverse Momentum Spectra inAu+AuandCu+CuCollisions atsNN=62.4and 200 GeV

Author

Burt Holzman, Christof Roland, Gunther Roland, W. T. Lin, Rachid Nouicer, Alice Mignerey, Chia-Ming Kuo, Adam Trzupek, I. Harnarine, R. Bindel, S. S. Vaurynovich, D. Willhelm, M. Ballintijn, T. Gburek, F. L. H. Wolfs, M. D. Baker, J. Hamblen, E. Richardson, A. Szostak, Bolek Wyslouch, David Jonathan Hofman, C. E. Smith, J. Sagerer, Russell Richard Betts, Conor Henderson, M. A. Stankiewicz, V. Chetluru, E. García, Andrzej Olszewski, K. Gulbrandsen, C. Loizides, R. Holynski, R. Verdier, Edward Allen Wenger, R. S. Hollis, I. Sedykh, Barbara Wosiek, Marguerite Tonjes, P. Kulinich, C. Reed, B. Alver, G. Van Nieuwenhuizen, A. Iordanova, J. L. Kane, Gabor Istvan Veres, Wei Li, Peter Steinberg, Z. Chai, S. Manly, George Stephans, Krzysztof Woźniak, A. Sukhanov, B. B. Back, Wit Busza, R. Pak, D. S. Barton, P. Walters, and S. M. Wyngaardt

Subjects
Physics, Nuclear reaction, Range (particle radiation), Quantitative Biology::Neurons and Cognition, 010308 nuclear & particles physics, Hadron, General Physics and Astronomy, chemistry.chemical_element, 7. Clean energy, 01 natural sciences, Copper, Spectral line, chemistry, Pseudorapidity, 0103 physical sciences, High Energy Physics::Experiment, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon, Energy (signal processing)
Abstract

We present transverse momentum distributions of charged hadrons produced in Cu+Cu collisions at {radical}(s{sub NN})=62.4 and 200 GeV. The spectra are measured for transverse momenta of 0.25

Published
2006

14. Charged Particle Multiplicities in Ultra-relativistic Au+Au and Cu+Cu Collisions

Author

Alice Mignerey, R. Bindel, H. Seals, Krzysztof Wozniak, A. S. Carroll, R. Verdier, Barbara Wosiek, Christof Roland, K. Gulbrandsen, Wei Li, C. Loizides, A. Sukhanov, A. Szostak, M. Hauer, George Stephans, Bolek Wyslouch, B. Alver, Wit Busza, P. Kulinich, Marguerite Tonjes, G.J. vanNieuwenhuizen, Z. Chai, N. Khan, R. S. Hollis, Burt Holzman, M. A. Stankiewicz, Edward Allen Wenger, C. Reed, I. Sedykh, M. P. Decowski, David Jonathan Hofman, T. Gburek, W. T. Lin, Rachid Nouicer, Andrzej Olszewski, C. Vale, N. George, F. L. H. Wolfs, D. S. Barton, C. E. Smith, A. A. Bickley, J. Sagerer, M. D. Baker, E. Richardson, Gabor Istvan Veres, Peter Steinberg, E. Johnson, S. M. Wyngaardt, A. Iordanova, R. Holynski, V. Chetluru, J. L. Kane, S. Manly, D. Willhelm, R. Pak, C. Halliwell, B. B. Back, Adam Trzupek, E. García, P. Walters, Russell Richard Betts, Conor Henderson, Chia-Ming Kuo, M. Ballintijn, S. S. Vaurynovich, J. Hamblen, Gunther Roland, and I. Harnarine

Subjects
Physics, Angular range, FOS: Physical sciences, Multiplicity (mathematics), Measure (mathematics), Charged particle, law.invention, Nuclear physics, law, Nuclear Experiment (nucl-ex), National laboratory, Collider, Nuclear Experiment
Abstract

The PHOBOS collaboration has carried out a systematic study of charged particle multiplicities in Cu+Cu and Au+Au collisions at the Relativistic Heavy-Ion Collider (RHIC) at Brookhaven National Laboratory. A unique feature of the PHOBOS detector is its ability to measure charged particles over a very wide angular range from 0.5 to 179.5 deg. corresponding to |eta, Proceedings of "Lake Louise Winter Institute 2006", Lake Louise, Alberta, Canada, February 17-23, 2006, World Scientific 5 pages, 3 figures

Published
2006
Full Text
View/download PDF

15. System size and centrality dependence of charged hadron transverse momentum spectra in Au + Au and Cu + Cu collisions at square root of SNN = 62.4 and 200 GeV

Author

B, Alver, B B, Back, M D, Baker, M, Ballintijn, D S, Barton, R R, Betts, R, Bindel, W, Busza, Z, Chai, V, Chetluru, E, García, T, Gburek, K, Gulbrandsen, J, Hamblen, I, Harnarine, C, Henderson, D J, Hofman, R S, Hollis, R, Hołyński, B, Holzman, A, Iordanova, J L, Kane, P, Kulinich, C M, Kuo, W, Li, W T, Lin, C, Loizides, S, Manly, A C, Mignerey, R, Nouicer, A, Olszewski, R, Pak, C, Reed, E, Richardson, C, Roland, G, Roland, J, Sagerer, I, Sedykh, C E, Smith, M A, Stankiewicz, P, Steinberg, G S F, Stephans, A, Sukhanov, A, Szostak, M B, Tonjes, A, Trzupek, G J, van Nieuwenhuizen, S S, Vaurynovich, R, Verdier, G I, Veres, P, Walters, E, Wenger, D, Willhelm, F L H, Wolfs, B, Wosiek, K, Woźniak, S, Wyngaardt, and B, Wysłouch

Abstract

We present transverse momentum distributions of charged hadrons produced in Cu + Cu collisions at square root of SNN = 62.4 and 200 GeV. The spectra are measured for transverse momenta of 0.25pT5.0 GeV/c at square root of SNN = 62.4 GeV and 0.25pT7.0 GeV/c at square root of SNN = 200 GeV, in a pseudorapidity range of 0.2eta1.4. The nuclear modification factor R(AA) is calculated relative to p + p data at both collision energies as a function of collision centrality. At a given collision energy and fractional cross section, R(AA) is observed to be systematically larger in Cu + Cu collisions compared to Au + Au. However, for the same number of participating nucleons, R(AA) is essentially the same in both systems over the measured range of pT, in spite of the significantly different geometries of the Cu + Cu and Au + Au systems.

Published
2005

16. The PHOBOS Collaboration

Author

J. Ligocki, M. Ballintijn, F.L.H. Wolfs, S. Basilev, J. Hamblen, E. Richardson, J. Sagerer, Johannes Mülmenstädt, M. Plesko, M. Despet, Rachid Nouicer, Jaw-Luen Tang, K. Surowiecka, Adam Trzupek, Jian Zhang, K. Gulbrandsen, C. Loizides, J. Sinacore, Z. Stopa, J. Katzy, M. Neal, M. Ceglia, M. A. Stankiewicz, J. Michałowski, Marek Stodulski, P. Kulinich, J. Fitch, K. Zalewski, P. Sawicki, Wei Li, C. Halliwell, D. Ross, Gabor Istvan Veres, Edward Allen Wenger, R. Baum, Peter Steinberg, George Stephans, E. Johnson, E. García, B.F. Wadsworth, H.W. Kraner, B. D. Bates, M. Reuter, A. Straczek, H. Seals, M. D. Baker, Marguerite Tonjes, P. Haridas, P. Żychowski, W. T. Lin, R. S. Hollis, P. Walters, I. Sedykh, A. E. Chen, Russell Richard Betts, Conor Henderson, Andrzej Olszewski, A. S. Carroll, L. P. Remsberg, R. Verdier, N. Khan, W. Kucewicz, M. Patel, R. Pak, A. Bialas, C. Reed, Christof Roland, David Jonathan Hofman, S. G. Steadman, Z. Chai, A. Sanzgiri, Krzysztof Woźniak, J. L. Kane, S. S. Vaurynovich, W. Bogucki, V. Chetluru, C. E. Smith, A. B. Hayes, M. P. Decowski, C. Vale, Heinz Pernegger, C. Conner, C. Gomes, J. Halik, A. Sukhanov, S. Manly, D. McLeod, P. Fita, M. Hauer, John P. Ryan, E. Griesmayer, Wit Busza, W. Skulski, Inkyu Park, Burt Holzman, Gunther Roland, N. George, Yuan-Hann Chang, W. Czyz, G. Van Nieuwenhuizen, I. Harnarine, A. Budzanowski, Barbara Wosiek, B. Alver, J. Scaduto, Bogdan Dabrowski, W. Kita, B. B. Back, Jan Godlewski, J.W. Lee, D. S. Barton, A. A. Bickley, R. Teng, M. Friedl, S. M. Wyngaardt, P. Sarin, T. Coghen, M. Strek, M. Lemler, S. Gushue, G. A. Heintzelman, K. Gałuszka, Bruce Becker, A. Szostak, Bolek Wyslouch, L.J. Rosenberg, Alice Mignerey, R. Bindel, T. Gburek, A. H. Wuosmaa, D. Willhelm, J. Shea, A. S. Harrington, R. Ganz, A. Noell, A. Iordanova, C. Law, R. Holynski, J. Kotula, and Chia-Ming Kuo

Subjects
Physics, Nuclear and High Energy Physics, Astronomy
Published
2009

17. New PHOBOS results on event-by-event fluctuations

Author

Chia-Ming Kuo, M. Ballintijn, J. Hamblen, Alice Mignerey, R. S. Hollis, R. Bindel, Barbara Wosiek, B. Alver, I. Sedykh, W. Skulski, F. L. H. Wolfs, C. E. Smith, Burt Holzman, C. Halliwell, Christof Roland, Gunther Roland, M. P. Decowski, G. Van Nieuwenhuizen, I. Harnarine, S. S. Vaurynovich, A. H. Wuosmaa, T. Gburek, A. Szostak, Bolek Wyslouch, L. P. Remsberg, D. S. Barton, Edward Allen Wenger, L.J. Rosenberg, A. A. Bickley, Gabor Istvan Veres, Peter Steinberg, P. Sarin, V. Chetluru, S. Gushue, A. Budzanowski, W. Kucewicz, E. Johnson, G. A. Heintzelman, A. S. Carroll, R. Verdier, M. Reuter, Russell Richard Betts, Conor Henderson, M. D. Baker, E. Richardson, J. Sagerer, P. Sawicki, Andrzej Olszewski, Jaw-Luen Tang, A. Sukhanov, S. M. Wyngaardt, Adam Trzupek, Wit Busza, R. Pak, Z. Chai, Krzysztof Woźniak, M. A. Stankiewicz, W. T. Lin, Rachid Nouicer, P. Walters, D. Willhelm, R. Holynski, N. Khan, E. García, Inkyu Park, N. George, A. Iordanova, P. Kulinich, K. Gulbrandsen, C. Loizides, J. L. Kane, S. Manly, David Jonathan Hofman, C. Vale, Marguerite Tonjes, C. Reed, B. B. Back, Wei Li, and George Stephans

Subjects
Physics, Nuclear physics, Nuclear reaction, Amplitude, Angular distribution, Quantitative Biology::Neurons and Cognition, Mathematical model, Pseudorapidity, Multiplicity (mathematics), Atomic physics, Nuclear Experiment, Anisotropy, Scaling
Abstract

We present new results from the PHOBOS experiment at RHIC on event‐by‐event fluctuations of particle multiplicities and angular distributions in nucleus‐nucleus collisions at RHIC. Our data for Au+Au collisions at sNN = 200 GeV show that at a level of 10−4 or less, no rare, large‐amplitude fluctuations in the total multiplicity distributions or the shape of the pseudorapidity distributions are observed. We however find significant short‐range multiplicity correlations in these data, that can be described as particle production in clusters. In Cu+Cu collisions, we observe large final‐state azimuthal anisotropies ν2. A common scaling behavior for Cu+Cu and Au+Au for these anisotropies emerges when fluctuations in the initial state geometry are taken into account.We present new results from the PHOBOS experiment at RHIC on event‐by‐event fluctuations of particle multiplicities and angular distributions in nucleus‐nucleus collisions at RHIC. Our data for Au+Au collisions at sNN = 200 GeV show that at a level of 10−4 or less, no rare, large‐amplitude fluctuations in the total multiplicity distributions or the shape of the pseudorapidity distributions are observed. We however find significant short‐range multiplicity correlations in these data, that can be described as particle production in clusters. In Cu+Cu collisions, we observe large final‐state azimuthal anisotropies ν2. A common scaling behavior for Cu+Cu and Au+Au for these anisotropies emerges when fluctuations in the initial state geometry are taken into account.

18. Fluctuations studies in PHOBOS

Author

Rachid Nouicer, Adam Trzupek, P. Steinberg, E. Richardson, Kinga Anna Wozniak, Gunther Roland, Alice Mignerey, C. E. Smith, M. A. Stankiewicz, A. Szostak, F. L. H. Wolfs, R. Bindel, I. Sedykh, Bolek Wyslouch, J. Sagerer, I. Harnarine, Burt Holzman, Barbara Wosiek, Z. Chai, D. J. Hofman, B. Alver, P. Kulinich, E. García, Christophe Pol A Roland, Chih-Yu Kuo, Wei Li, S. S. Vaurynovich, Gabor Istvan Veres, Russell Richard Betts, Conor Henderson, T. Gburek, George Stephans, D. Willhelm, J. L. Kane, Constantin Loizides, G.J. vanNieuwenhuizen, M. Ballintijn, Edward Allen Wenger, K. Gulbrandsen, R. S. Hollis, M. D. Baker, J. Hamblen, M. B. Tonjes, V. Chetluru, S. Manly, A. Sukhanov, Wit Busza, R. Pak, C. Reed, R. Holynski, P. Walters, R. Verdier, A. Iordanova, B. B. Back, Andrzej Olszewski, W. T. Lin, S. M. Wyngaardt, and D. S. Barton

19. Predicting Van der Waals Heterostructures by a Combined Machine Learning and Density Functional Theory Approach.

Author

Willhelm D, Wilson N, Arroyave R, Qian X, Cagin T, Pachter R, and Qian X

Abstract

Van der Waals (vdW) heterostructures are constructed by different two-dimensional (2D) monolayers vertically stacked and weakly coupled by van der Waals interactions. VdW heterostructures often possess rich physical and chemical properties that are unique to their constituent monolayers. As many 2D materials have been recently identified, the combinatorial configuration space of vdW-stacked heterostructures grows exceedingly large, making it difficult to explore through traditional experimental or computational approaches in a trial-and-error manner. Here, we present a computational framework that combines first-principles electronic structure calculations, 2D material database, and supervised machine learning methods to construct efficient data-driven models capable of predicting electronic and structural properties of vdW heterostructures from their constituent monolayer properties. We apply this approach to predict the band gap, band edges, interlayer distance, and interlayer binding energy of vdW heterostructures. Our data-driven model will open avenues for efficient screening and discovery of low-dimensional vdW heterostructures and moiré superlattices with desired electronic and optical properties for targeted device applications.

Published
2022
Full Text
View/download PDF

20. All-nanoparticle layer-by-layer coatings for Mid-IR on-chip gas sensing.

Author

Al Husseini D, Zhou J, Willhelm D, Hastings T, Day GS, Zhou HC, Coté GL, Qian X, Gutierrez-Osuna R, Lin PT, and Sukhishvili SA

Abstract

Functionalization of optical waveguides with submicron coatings of zinc peroxide (ZnO 2 ) and silica (SiO 2 ) nanoparticles (NPs) is reported that enabled selective concentration of acetone vapors in the vicinity of the waveguide, boosting the sensitivity of a mid infrared (MIR) on-chip detector. Controlled thickness was achieved by introducing precise control of the substrate withdrawal speed to the layer-by-layer (LbL) deposition technique.

Published
2020
Full Text
View/download PDF

21. System size, energy, and centrality dependence of pseudorapidity distributions of charged particles in relativistic heavy-ion collisions.

Author

Alver B, Back BB, Baker MD, Ballintijn M, Barton DS, Betts RR, Bindel R, Busza W, Chai Z, Chetluru V, García E, Gburek T, Gulbrandsen K, Hamblen J, Harnarine I, Henderson C, Hofman DJ, Hollis RS, Hołyński R, Holzman B, Iordanova A, Kane JL, Kulinich P, Kuo CM, Li W, Lin WT, Loizides C, Manly S, Mignerey AC, Nouicer R, Olszewski A, Pak R, Reed C, Richardson E, Roland C, Roland G, Sagerer J, Sedykh I, Smith CE, Stankiewicz MA, Steinberg P, Stephans GS, Sukhanov A, Szostak A, Tonjes MB, Trzupek A, van Nieuwenhuizen GJ, Vaurynovich SS, Verdier R, Veres GI, Walters P, Wenger E, Willhelm D, Wolfs FL, Wosiek B, Woźniak K, Wyngaardt S, and Wysłouch B

Abstract

We present the first measurements of the pseudorapidity distribution of primary charged particles in Cu+Cu collisions as a function of collision centrality and energy, sqrt[s&#95;{NN}]=22.4, 62.4, and 200 GeV, over a wide range of pseudorapidity, using the PHOBOS detector. A comparison of Cu+Cu and Au+Au results shows that the total number of produced charged particles and the rough shape (height and width) of the pseudorapidity distributions are determined by the number of nucleon participants. More detailed studies reveal that a more precise matching of the shape of the Cu+Cu and Au+Au pseudorapidity distributions over the full range of pseudorapidity occurs for the same N{part}/2A rather than the same N&#95;{part}. In other words, it is the collision geometry rather than just the number of nucleon participants that drives the detailed shape of the pseudorapidity distribution and its centrality dependence at RHIC energies.

Published
2009
Full Text
View/download PDF

22. System size, energy, pseudorapidity, and centrality dependence of elliptic flow.

Author

Alver B, Back BB, Baker MD, Ballintijn M, Barton DS, Betts RR, Bickley AA, Bindel R, Busza W, Carroll A, Chai Z, Chetluru V, Decowski MP, García E, Gburek T, George N, Gulbrandsen K, Halliwell C, Hamblen J, Harnarine I, Hauer M, Henderson C, Hofman DJ, Hollis RS, Hołyński R, Holzman B, Iordanova A, Johnson E, Kane JL, Khan N, Kulinich P, Kuo CM, Li W, Lin WT, Loizides C, Manly S, Mignerey AC, Nouicer R, Olszewski A, Pak R, Reed C, Richardson E, Roland C, Roland G, Sagerer J, Seals H, Sedykh I, Smith CE, Stankiewicz MA, Steinberg P, Stephans GS, Sukhanov A, Szostak A, Tonjes MB, Trzupek A, Vale C, van Nieuwenhuizen GJ, Vaurynovich SS, Verdier R, Veres GI, Walters P, Wenger E, Willhelm D, Wolfs FL, Wosiek B, Woźniak K, Wyngaardt S, and Wysłouch B

Abstract

This Letter presents measurements of the elliptic flow of charged particles as a function of pseudorapidity and centrality from Cu-Cu collisions at 62.4 and 200 GeV using the PHOBOS detector at the Relativistic Heavy Ion Collider. The elliptic flow in Cu-Cu collisions is found to be significant even for the most central events. For comparison with the Au-Au results, it is found that the detailed way in which the collision geometry (eccentricity) is estimated is of critical importance when scaling out system-size effects. A new form of eccentricity, called the participant eccentricity, is introduced which yields a scaled elliptic flow in the Cu-Cu system that has the same relative magnitude and qualitative features as that in the Au-Au system.

Published
2007
Full Text
View/download PDF

23. System size and centrality dependence of charged hadron transverse momentum spectra in Au + Au and Cu + Cu collisions at square root of SNN = 62.4 and 200 GeV.

Author

Alver B, Back BB, Baker MD, Ballintijn M, Barton DS, Betts RR, Bindel R, Busza W, Chai Z, Chetluru V, García E, Gburek T, Gulbrandsen K, Hamblen J, Harnarine I, Henderson C, Hofman DJ, Hollis RS, Hołyński R, Holzman B, Iordanova A, Kane JL, Kulinich P, Kuo CM, Li W, Lin WT, Loizides C, Manly S, Mignerey AC, Nouicer R, Olszewski A, Pak R, Reed C, Richardson E, Roland C, Roland G, Sagerer J, Sedykh I, Smith CE, Stankiewicz MA, Steinberg P, Stephans GS, Sukhanov A, Szostak A, Tonjes MB, Trzupek A, van Nieuwenhuizen GJ, Vaurynovich SS, Verdier R, Veres GI, Walters P, Wenger E, Willhelm D, Wolfs FL, Wosiek B, Woźniak K, Wyngaardt S, and Wysłouch B

Abstract

We present transverse momentum distributions of charged hadrons produced in Cu + Cu collisions at square root of SNN = 62.4 and 200 GeV. The spectra are measured for transverse momenta of 0.25 < pT < 5.0 GeV/c at square root of SNN = 62.4 GeV and 0.25 < pT < 7.0 GeV/c at square root of SNN = 200 GeV, in a pseudorapidity range of 0.2 < eta < 1.4. The nuclear modification factor R(AA) is calculated relative to p + p data at both collision energies as a function of collision centrality. At a given collision energy and fractional cross section, R(AA) is observed to be systematically larger in Cu + Cu collisions compared to Au + Au. However, for the same number of participating nucleons, R(AA) is essentially the same in both systems over the measured range of pT, in spite of the significantly different geometries of the Cu + Cu and Au + Au systems.

Published
2006
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results