Search

Your search keyword '"Roy A. Lacey"' showing total 199 results
Start Over Author "Roy A. Lacey"
199 results on '"Roy A. Lacey"'

1. Azimuthal dependence of two-particle transverse momentum current correlations

Author

Niseem Magdy, Sumit Basu, Victor Gonzalez, Ana Marin, Olga Evdokimov, Roy A. Lacey, and Claude Pruneau

Subjects
Astrophysics, QB460-466, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

Abstract Two-particle transverse momentum correlation functions are a powerful technique for understanding the dynamics of relativistic heavy-ion collisions. Among these, the transverse momentum correlator $$G_{2}\left( \varDelta \eta ,\varDelta \varphi \right) $$ G 2 Δ η , Δ φ is of particular interest for its potential sensitivity to the shear viscosity per unit of entropy density $$\eta /s$$ η / s of the quark-gluon plasma formed in heavy-ion collisions. We use the UrQMD, AMPT, and EPOS models for Au–Au at $$\sqrt{s_\mathrm{NN}}$$ s NN = 200 GeV and Pb–Pb at $$\sqrt{s_\mathrm{NN}}$$ s NN = 2760 GeV to investigate the long range azimuthal dependence of $$G_{2}\left( \varDelta \eta ,\varDelta \varphi \right) $$ G 2 Δ η , Δ φ , and explore its utility to constrain $$\eta /s$$ η / s based on charged particle correlations. We find that the three models yield quantitatively distinct transverse momentum Fourier harmonics coefficients $$a^{p_\mathrm{T}}_{n}$$ a n p T . We also observe these coefficients exhibit a significant dependence on $$\eta /s$$ η / s in the context of the AMPT model. These observations suggest that exhaustive measurements of the dependence of $$G_{2}\left( \varDelta \varphi \right) $$ G 2 Δ φ with collision energy, system size, collision centrality, in particular, offer the potential to distinguish between different theoretical models and their underlying assumptions. Exhaustive analyses of $$G_{2}\left( \varDelta \varphi \right) $$ G 2 Δ φ obtained in large and small systems should also be instrumental in establishing new constraints for precise extraction of $$\eta /s$$ η / s .

Published
2021
Full Text
View/download PDF

2. Model investigations of the correlation between the mean transverse momentum and anisotropic flow in shape-engineered events

Author

Niseem Magdy and Roy A. Lacey

Subjects
Physics, QC1-999
Abstract

The correlation between the event mean-transverse momentum [pT], and the anisotropic flow magnitude vn, ρ(vn2,[pT]), has been argued to be sensitive to the initial conditions in heavy-ion collisions. We use simulated events generated with the AMPT and EPOS models for Au+Au at sNN = 200 GeV, to investigate the model dependence and the response and sensitivity of the ρ(v22,[pT]) correlator to collision-system size and shape, and the viscosity of the matter produced in the collisions. We find good qualitative agreement between the correlators for the string melting version of the AMPT model and the EPOS model. The model investigations for shape-engineered events as well as events with different viscosity (η/s), indicate that ρ(v22,[pT]) is sensitive to the initial-state geometry of the collision system but is insensitive to sizable changes in η/s for the medium produced in the collisions. These findings suggest that precise differential measurements of ρ(v22,[pT]) as a function of system size, shape, and beam-energy could provide more stringent constraints to discern between initial-state models and hence, more reliable extractions of η/s.

Published
2021
Full Text
View/download PDF

3. An extended RΨm(2)(ΔS2) correlator for detecting and characterizing the Chiral Magnetic Wave

Author

Niseem Magdy, Mao-Wu Nie, Ling Huang, Guo-Liang Ma, and Roy A. Lacey

Subjects
Physics, QC1-999
Abstract

The extended RΨm(2)(ΔS2) correlator is presented and examined for its efficacy to detect and characterize the quadrupole charge separation (ΔS2) associated with the purported Chiral Magnetic Wave (CMW) produced in heavy-ion collisions. Sensitivity tests involving varying degrees of charge separation injected into events simulated with the Multi-Phase Transport Model (AMPT) show that the RΨm(2)(ΔS2) correlators provide discernible responses for the background- and signal-driven quadrupole charge separation. This distinction could help identify CMW-induced quadrupole charge separation via measurements of the RΨ2(2)(ΔS2) and RΨ3(2)(ΔS2) correlators, relative to the second- (Ψ2) and third-order (Ψ3) event planes. The tests also indicate a sensitivity level that would allow for robust experimental characterization of possible CMW-induced charge separation.

Published
2020
Full Text
View/download PDF

4. A sensitivity study of the primary correlators used to characterize chiral-magnetically-driven charge separation

Author

Niseem Magdy, Mao-Wu Nie, Guo-Liang Ma, and Roy A. Lacey

Subjects
Physics, QC1-999
Abstract

A Multi-Phase Transport (AMPT) model is used to study the detection sensitivity of two of the primary correlators – Δγ and RΨ2 – employed to characterize charge separation induced by the Chiral Magnetic Effect (CME). The study, performed relative to several event planes for different input “CME signals”, indicates a detection threshold for the fraction fCME=ΔγCME/Δγ, which renders the Δγ-correlator insensitive to values of the Fourier dipole coefficient a1≲2.5%, that is larger than the purported signal (signal difference) for ion-ion(isobaric) collisions. By contrast, the RΨ2 correlator indicates concave-shaped distributions with inverse widths (σRΨ2−1) that are linearly proportional to a1, and independent of the character of the event plane used for their extraction. The sensitivity of the RΨ2 correlator to minimal CME-driven charge separation in the presence of realistic backgrounds, could aid better characterization of the CME in heavy-ion collisions.

Published
2020
Full Text
View/download PDF

6. Event Patterns Extracted from Transverse Momentum and Rapidity Spectra of Z Bosons and Quarkonium States Produced in pp and Pb-Pb Collisions at LHC

Author

Ya-Hui Chen, Fu-Hu Liu, and Roy A. Lacey

Subjects
Physics, QC1-999
Abstract

Transverse momentum (pT) and rapidity (y) spectra of Z bosons and quarkonium states (some charmonium cc¯ mesons such as J/ψ and ψ(2S) and some bottomonium bb¯ mesons such as Υ(1S), Υ(2S), and Υ(3S)) produced in proton-proton (pp) and lead-lead (Pb-Pb) collisions at the large hadron collider (LHC) are uniformly described by a hybrid model of two-component Erlang distribution for pT spectrum and two-component Gaussian distribution for y spectrum. The former distribution results from a multisource thermal model, and the latter one results from the revised Landau hydrodynamic model. The modelling results are in agreement with the experimental data measured in pp collisions at center-of-mass energies s=2.76 and 7 TeV and in Pb-Pb collisions at center-of-mass energy per nucleon pair sNN=2.76 TeV. Based on the parameter values extracted from pT and y spectra, the event patterns (particle scatter plots) in two-dimensional pT-y space and in three-dimensional velocity space are obtained.

Published
2016
Full Text
View/download PDF

7. Searching for Minimum in Dependence of Squared Speed-of-Sound on Collision Energy

Author

Fu-Hu Liu, Li-Na Gao, and Roy A. Lacey

Subjects
Physics, QC1-999
Abstract

Experimental results of the rapidity distributions of negatively charged pions produced in proton-proton (p-p) and beryllium-beryllium (Be-Be) collisions at different beam momentums, measured by the NA61/SHINE Collaboration at the super proton synchrotron (SPS), are described by a revised (three-source) Landau hydrodynamic model. The squared speed-of-sound parameter cs2 is then extracted from the width of rapidity distribution. There is a local minimum (knee point) which indicates a softest point in the equation of state (EoS) appearing at about 40A GeV/c (or 8.8 GeV) in cs2 excitation function (the dependence of cs2 on incident beam momentum (or center-of-mass energy)). This knee point should be related to the searching for the onset of quark deconfinement and the critical point of quark-gluon plasma (QGP) phase transition.

Published
2016
Full Text
View/download PDF

8. Scaling Properties of the Mean Multiplicity and Pseudorapidity Density in e−+e+, e±+p, p( p ¯ )+p, p+A and A+A(B) Collisions

Author

Roy A. Lacey, Peifeng Liu, Niseem Magdy, Máté Csanád, Benjamin Schweid, Nuggehalli N. Ajitanand, John Alexander, and Robert Pak

Subjects
multiplicity scaling, leading particle effect, effective energy, participant scaling, Elementary particle physics, QC793-793.5
Abstract

The charged-particle pseudorapidity density ( d N ch / d η ) for p( p ¯ )+p, p+A and A+A(B) collisions and the mean multiplicity 〈 N ch 〉 for e − +e + , e ± + p , and p( p ¯ )+p collisions are studied for a wide range of beam energies ( s ). Characteristic scaling patterns are observed for both d N ch / d η and 〈 N ch 〉 , consistent with a thermal particle production mechanism for the bulk of the soft particles created in all of these systems. The scaling patterns found also validate an essential role for quark participants in these collisions. The measured values for d N ch / d η and 〈 N ch 〉 are observed to factorize into contributions that depend on log ( s ) and the number of nucleon or quark participant pairs N pp . The quantification of these contributions gives expressions that serve to systematize d N ch / d η and 〈 N ch 〉 measurements spanning nearly 4 orders of magnitude in s and to predict their values as a function of s and N pp .

Published
2018
Full Text
View/download PDF

9. Model study of the energy dependence of the correlation between anisotropic flow and the mean transverse momentum in Au+Au collisions

Author

Niseem Magdy, Petr Parfenov, Arkadiy Taranenko, Iurii Karpenko, and Roy A. Lacey

Subjects
Nuclear Theory (nucl-th), High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), Nuclear Theory, FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

A hybrid model that employs the hadron-string transport model UrQMD and the (3+1)D relativistic viscous hydrodynamic code vHLLE, is used to investigate the beam energy dependence of the correlation coefficient $\rho(v^{2}_{2},[p_{T}])$ between the average transverse momentum $[p_{T}]$ of hadrons emitted in an event and the square of the anisotropic flow coefficient $v_2^2$. For Au+Au collisions, the model predicts characteristic patterns for the energy and event-shape dependence of the variances for $[p_{T}]$ and $v_n^2$ (${\rm Var}([p_T])$ and ${\rm Var}(v_2^2)$), and the covariance of $v_n^2$ and $[p_{T}]$ (${\rm cov}(v_{2}^{2},[p_T])$), consistent with the attenuation effects of the specific shear viscosity $\eta/s$. In contrast, $\rho(v^{2}_{2},[p_{T}])$ is predicted to be insensitive to the beam energy but sensitive to the initial-state geometry of the collisions. These observations suggest that a precise set of measurements for ${\rm Var}([p_T])$, ${\rm Var}(v_2^2)$, ${\rm cov}(v_{2}^{2},[p_T])$ and $\rho(v^{2}_{2},[p_{T}])$ as a function of beam-energy and event-shape, could aid precision extraction of the temperature and baryon chemical-potential dependence of $\eta/s$ from the wealth of Au+Au data obtained in the RHIC beam energy scan., Comment: 6 pages, 6 figures, submitted for publication

Published
2021
Full Text
View/download PDF

10. Strange hadron production in Au+Au collisions at sNN=7.7 , 11.5, 19.6, 27, and 39 GeV

Author

S. Fazio, I. G. Bordyuzhin, James Brandenburg, K. N. Barish, Z. Ye, T. Tarnowsky, Maowu Nie, A. Kechechyan, Pradip Kumar Sahu, Maria Stefaniak, Lukas Holub, Subhasis Chattopadhyay, Bedangadas Mohanty, F. G. Atetalla, G. Eppley, Pavol Federic, A. A. Derevschikov, Dingwei Zhang, J. Pluta, N. Chankova-Bunzarova, Muhammad Usman Ashraf, Skipper Kagamaster, Subhash Singha, Y. K. Sun, Bernd Surrow, Paul Sorensen, Rene Bellwied, Brian Page, Yifan Hong, John Nelson, Nu Xu, Raghav Kunnawalkam Elayavalli, Xiangming Sun, Kejun Kang, L. V. Nogach, Jana Bielcikova, B. Huang, Z. Moravcova, N. K. Pruthi, O. D. Tsai, Xinyue Ju, Zhen Liu, Feng Liu, Norbert Herrmann, N. Elsey, J. Putschke, Chris Perkins, K. Gopal, Lanny Ray, A. V. Brandin, Janet Elizabeth Seger, Z. Chang, I. M. Deppner, Song Zhang, Neha Shah, Zebo Tang, A. Ogawa, Takafumi Niida, Vipul Bairathi, Lokesh Kumar, C. A. Gagliardi, Hans Georg Ritter, Jeong-Hun Lee, Peifeng Liu, F. Videbæk, Dmitri Smirnov, Hal Spinka, D. P. Kikola, H. Liu, Joseph Kwasizur, C. Zhong, E. C. Aschenauer, Wen-Qing Shen, Jaroslav Adam, Madan M. Aggarwal, David Stewart, Irakli Chakaberia, B. Stringfellow, Saskia Mioduszewski, Shusu Shi, M. Tokarev, Yang Yang, Matthew Kelsey, Yuanjing Ji, J. Engelage, Robert E. Tribble, Fuqiang Wang, D. K. Mishra, L. Didenko, Y. Fisyak, Qian Yang, Xiaolong Chen, Yaping Wang, Arabinda Behera, Richard Daniel Majka, X. Dong, B. Schmidke, Liang He, Hao-jie Xu, I. K. Yoo, Xiaoyu Liu, P. Chaloupka, Ting Lin, K. Oh, Chitrasen Jena, X. Zhu, Yifei Zhang, G. Nigmatkulov, Alexandre Alarcon Do Passo Suaide, Rongrong Ma, S. W. Wissink, Miroslav Simko, Ron Longacre, Mariusz Przybycien, F. Seck, P. Szymanski, A. I. Hamad, Sedigheh Jowzaee, Isaac Upsal, Dave Underwood, Xinjie Huang, Prithwish Tribedy, B. K. Srivastava, Juan M. Romero, Sevil Salur, M. Sergeeva, Qinghua Xu, Maksym Zyzak, J. Rusnak, Christina Markert, H. H. Wieman, O. Rusnakova, H. S. Matis, Nihar Sahoo, Cheng Li, D. Kapukchyan, Declan Keane, J. M. Landgraf, M. Lomnitz, Diana Pawlowska, L. K. Kosarzewski, E. P. Sichtermann, J. Lauret, Jing-Han Chen, Qiye Shou, Shengli Huang, M. Posik, H. W. Ke, L. Fulek, M. M. Mondal, E. G. Judd, P. Seyboth, Jan Vanek, Leszek Adamczyk, Shuai Yang, J. Schambach, D. Kalinkin, Xiaofeng Luo, Guo-Liang Ma, Chensheng Zhou, Alexander Vasiliev, Yevheniia Khyzhniak, S. Stanislaus, L. Kochenda, J. W. Harris, M. Kocan, Robert Licenik, I. G. Alekseev, Anthony Robert Timmins, Adam Ryszard Kisiel, Chong Kim, Siwei Luo, Anju Bhasin, R. Seto, Jianping Cheng, Li Yi, Z. Tu, M. A. Lisa, J. C. Mei, Tetsuro Sugiura, A. J. Bassill, J. C. Dunlop, L. Wen, L. Ruan, ShinIchi Esumi, B. K. Chan, Michal Sumbera, T. Ullrich, S. Heppelmann, C. Dilks, Roland Laszlo Pinter, Xin Li, B. J. Summa, Jaroslav Bielcik, T. G. Dedovich, Dmitry Morozov, M. Strikhanov, K. Yip, Zubayer Ahammed, Joseph Adams, Catherine Tomkiel, Hank Crawford, H. Z. Huang, Kishora Nayak, Rafal Sikora, S. Kabana, Ivan Kisel, P. Kravtsov, Fuwang Shen, J. Bryslawskyj, R. Fatemi, A. Lebedev, Manuel Calderon De La Barca Sanchez, Gang Wang, I. Bunzarov, O. Matonoha, Norbert Schmitz, Z. Y. Zhang, Yu-Gang Ma, Jiangyong Jia, Todd Kinghorn, Nalinda Kulathunga Mudiyanselage, O. V. Rogachevskiy, Vitalii Okorokov, Yi Wang, T. Nonaka, T. Todoroki, Guannan Xie, Isaac Mooney, Shenghui Zhang, Ming Shao, L. C. Bland, Arghya Chatterjee, R. Lednicky, Wei Li, Justin Ewigleben, A. Gibson, G. Odyniec, J. Sandweiss, William Jacobs, Hanna Paulina Zbroszczyk, Roli Esha, Feng-Han Chang, A. K. Bhati, T. Ljubicic, Wei Xie, M. Cherney, I. Vassiliev, Chi Yang, Rosi Reed, Daniel Nemes, S. Siejka, J. H. Thomas, Yuliang Sun, Jie Zhao, H. Caines, Yi-Fei Xu, A. Quintero, A. H. Tang, Mate Csanad, Hua Pei, Nasim, D. N. Svirida, S. K. Tripathy, R. Pak, A. Aparin, S. Ramachandran, J. L. Drachenberg, Olga Evdokimov, Yuanjing Li, Niseem Magdy Abdelwahab Abdelrahman, G. S. Averichev, Zhigang Xiao, Jagbir Singh, T. Huang, Nikolai Smirnov, O. Eyser, W. J. Llope, Joel Anthony Mazer, Z. Yang, Derek Anderson, Kun Jiang, Jay Roberts, Benjamin Schweid, T. J. Humanic, Alexander Jentsch, Zhenyu Ye, N. G. Minaev, Maria Zurek, A. Attri, K. Krueger, P. Huo, D. Arkhipkin, A. Hamed, E. Shahaliev, P. Filip, Yicheng Feng, Yang Wu, Anik Gupta, R. Witt, Lei Zhang, Xiaoping Zhang, J. M. Butterworth, Sergei A. Voloshin, Spiros Margetis, Gene Van Buren, Bill Christie, J. C. Webb, D. Tlusty, A. Lipiec, Zhongbin Xu, Lukas Kramarik, Frank Jm Geurts, T. Galatyuk, Sooraj Krishnan Radhakrishnan, E. Finch, W. Zha, Peng Liu, Wlodek Guryn, S. Vokal, Yue Liang, Y. Panebratsev, W. Solyst, Saehanseul Oh, D. Grosnick, J. Porter, R. Aoyama, Samuel Heppelmann, B. Tu, Tong Liu, S. Das, K. Meehan, G. Agakishiev, S. Horvat, Roy A. Lacey, T. Edmonds, Pengfei Wang, Gary Westfall, D. Cebra, S. Trentalange, Zhanwen Zhu, Kevin Adkins, Long Ma, Yanfang Liu, J. Fedorisin, B. Pawlik, P. V. Shanmuganathan, D. Mallick, G. Igo, K. Kauder, and A. Taranenko

Subjects
Physics, Strange quark, 010308 nuclear & particles physics, Nuclear Theory, Hadron, Strangeness production, Strangeness, 01 natural sciences, Baryon, Nuclear physics, 0103 physical sciences, Transverse mass, High Energy Physics::Experiment, Impact parameter, Nuclear Experiment, 010306 general physics, Relativistic Heavy Ion Collider
Abstract

We present STAR measurements of strange hadron (KS0, Λ, Λ¯, Ξ−, Ξ¯+, Ω−, Ω¯+, and ϕ) production at midrapidity (|y

Published
2020

11. Underlying event measurements in p+p collisions at s=200 GeV at RHIC

Author

F. G. Atetalla, X. Zhu, Xiangming Sun, A. H. Tang, Christina Markert, Lokesh Kumar, Lawrence Pinsky, Wen-Qing Shen, H. S. Matis, Z. Chang, H. Sako, P. C. Weidenkaff, Jaroslav Adam, Lukas Holub, Bedangadas Mohanty, Siwei Luo, L. K. Kosarzewski, Y. H. Leung, D. Kincses, Saskia Mioduszewski, Shusu Shi, S. Lan, Zhongbin Xu, K. Gopal, Z. Moravcova, S. Vokal, Yue Liang, F. Seck, Lanny Ray, Robert E. Tribble, Xiaolong Chen, Arabinda Behera, B. K. Chan, Michal Sumbera, M. Posik, Benjamin Schweid, T. J. Humanic, Catherine Tomkiel, Hank Crawford, D. Neff, Lukas Kramarik, Paul Sorensen, J. Lauret, N. K. Pruthi, G. Agakishiev, A. Hamed, Audrey Francisco, Sooraj Krishnan Radhakrishnan, Rongrong Ma, Xiaoyu Liu, E. G. Judd, T. G. Dedovich, Nihar Sahoo, S. Horvat, D. Cebra, J. Rusnak, E. Finch, Yevheniia Khyzhniak, S. Trentalange, Joseph Kwasizur, S. Stanislaus, L. Kochenda, H. Liu, Z. Tu, A. I. Hamad, Sedigheh Jowzaee, Dave Underwood, Yuanjing Ji, Zhanwen Zhu, M. Kocan, L. Ruan, C. J. Feng, G. Eppley, Joseph Adams, J. Engelage, G. Nigmatkulov, F. Videbæk, James Brandenburg, Robert Licenik, Anthony Robert Timmins, Adam Ryszard Kisiel, Yi Wang, T. Nonaka, Wei Li, David Stewart, Ivan Kisel, Declan Keane, Jiangyong Jia, D. P. Kikola, Long Ma, B. Stringfellow, J. C. Dunlop, L. Wen, Isaac Upsal, Roy A. Lacey, T. Edmonds, J. Pluta, K. N. Barish, Wei Xie, J. D. Nam, Pengfei Wang, Alexander Kiselev, B. Schmidke, Chris Perkins, N. Chankova-Bunzarova, Skipper Kagamaster, Subhash Singha, S. Fazio, Chitrasen Jena, Sevil Salur, Yanfang Liu, Roland Laszlo Pinter, R. Fatemi, A. Aparin, Yifan Hong, Yu Zhang, J. W. Harris, Z. Ye, M. S. Daugherity, I. G. Bordyuzhin, J. M. Landgraf, Rene Bellwied, P. V. Shanmuganathan, D. Chen, Dmitry Morozov, Yifei Zhang, Diana Pawlowska, J. Fedorisin, Zhiwan Xu, Isaac Mooney, Shenghui Zhang, Todd Kinghorn, Maowu Nie, Song Zhang, T. Tarnowsky, Ming Shao, B. Pawlik, Zebo Tang, I. G. Alekseev, William Jacobs, E. P. Sichtermann, E. Shahaliev, H. W. Ke, Zubayer Ahammed, N. S. Lukow, M. A. Lisa, Alexander Vasiliev, L. Fulek, M. Strikhanov, D. Mallick, L. C. Bland, Xiaofeng Luo, Guo-Liang Ma, A. Kechechyan, Norbert Schmitz, M. Cherney, Yaping Wang, Rosi Reed, D. Kalinkin, Y. Xu, Marton Imre Nagy, J. H. Thomas, S. Heppelmann, Xin Li, B. J. Summa, Yuliang Sun, P. Chaloupka, I. Vassiliev, Ting Lin, Nu Xu, Li Yi, Z. P. Zhang, Hua Pei, S. K. Tripathy, G. Igo, Pavol Federic, A. A. Derevschikov, Feng-Han Chang, Gary Westfall, Raghav Kunnawalkam Elayavalli, Shu He, A. Gibson, G. Odyniec, Jing-Han Chen, Kevin Adkins, Z. Y. Zhang, Qiye Shou, Kejun Kang, L. V. Nogach, Muhammad Usman Ashraf, J. Sandweiss, S. Kabana, Chi Yang, Jian-Song Wang, Mate Csanad, Nasim, P. Kravtsov, Fuwang Shen, Peng Liu, Wlodek Guryn, Y. Panebratsev, Nalinda Kulathunga Mudiyanselage, Saehanseul Oh, D. Grosnick, Alexandre Alarcon Do Passo Suaide, Qinghua Xu, Yi-Fei Xu, X. H. He, Niseem Magdy Abdelwahab Abdelrahman, Maksym Zyzak, Z. Wang, S. Ramachandran, D. N. Svirida, Janet Elizabeth Seger, Joel Anthony Mazer, Z. Yang, O. D. Tsai, Cheng Li, D. Kapukchyan, R. Pak, Chensheng Zhou, Norbert Herrmann, Spiros Margetis, O. Eyser, Xinyue Ju, Zhen Liu, K. Kauder, A. Taranenko, Sergei A. Voloshin, Feng Liu, Kishora Nayak, Maria Stefaniak, J. Putschke, Y. Fisyak, Zhigang Xiao, D. Tlusty, Jagbir Singh, T. Huang, J. M. Butterworth, D. Isenhower, Z. Chen, J. C. Webb, Yuanjing Li, G. S. Averichev, Derek Anderson, I. M. Deppner, H. Qiu, M. Tokarev, Yang Yang, Matthew Kelsey, T. Ullrich, Hans Georg Ritter, A. Ogawa, Anju Bhasin, Roli Esha, R. Seto, Samuel Heppelmann, P. Szymanski, N. G. Minaev, Daniel Nemes, Tong Liu, Chong Kim, Xinjie Huang, B. Kimelman, Peifeng Liu, Jie Zhao, H. H. Wieman, W. Solyst, Prithwish Tribedy, B. K. Srivastava, Juan M. Romero, H. Z. Huang, Dingwei Zhang, A. Pandav, M. Chevalier, Y. Hu, E. Hoffman, Rafal Sikora, Shengli Huang, P. Filip, P. Seyboth, Hal Spinka, A. Lebedev, J. L. Drachenberg, M. Sergeeva, Jana Bielcikova, Olga Evdokimov, Annika Ewigleben, Manuel Calderon De La Barca Sanchez, Gang Wang, Jan Vanek, Leszek Adamczyk, Gene Van Buren, Susumu Sato, W. Zha, Nikolai Smirnov, Xiaoping Zhang, T. Ljubicic, Kun Jiang, J. Porter, Jay Roberts, Zhenyu Ye, Hao-jie Xu, Brian Page, Maria Zurek, H. Caines, A. V. Brandin, W. He, Bill Christie, K. Krueger, Jianping Cheng, A. Quintero, Subikash Choudhury, Yicheng Feng, Takafumi Niida, Vipul Bairathi, R. Witt, Irakli Chakaberia, Neha Shah, C. Zhong, E. C. Aschenauer, Arghya Chatterjee, L. Didenko, X. Dong, Jeong-Hun Lee, Miroslav Simko, Ron Longacre, Mariusz Przybycien, Shuai Yang, Jaroslav Bielcik, O. V. Rogachevskiy, Vitalii Okorokov, Yang Wu, Yufu Lin, Frank Jm Geurts, T. Galatyuk, Guannan Xie, R. Lednicky, Hanna Paulina Zbroszczyk, Qian Yang, Richard Daniel Majka, Y. K. Sun, Bernd Surrow, K. Yip, S. W. Wissink, ShinIchi Esumi, N. Elsey, Latiful Kabir, Yu-Gang Ma, C. A. Gagliardi, W. J. Llope, Alexander Jentsch, Madan M. Aggarwal, A. Attri, Fuqiang Wang, P. Huo, and John Nelson

Subjects
Physics, Proton, Transverse momentum, Chatterjee, Underlying event, Mathematical physics
Abstract

Author(s): Adam, J; Adamczyk, L; Adams, JR; Adkins, JK; Agakishiev, G; Aggarwal, MM; Ahammed, Z; Alekseev, I; Anderson, DM; Aparin, A; Aschenauer, EC; Ashraf, MU; Atetalla, FG; Attri, A; Averichev, GS; Bairathi, V; Barish, K; Behera, A; Bellwied, R; Bhasin, A; Bielcik, J; Bielcikova, J; Bland, LC; Bordyuzhin, IG; Brandenburg, JD; Brandin, AV; Butterworth, J; Caines, H; Calderon De La Barca Sanchez, M; Cebra, D; Chakaberia, I; Chaloupka, P; Chan, BK; Chang, FH; Chang, Z; Chankova-Bunzarova, N; Chatterjee, A; Chen, D; Chen, JH; Chen, X; Chen, Z; Cheng, J; Cherney, M; Chevalier, M; Choudhury, S; Christie, W; Crawford, HJ; Csanad, M; Daugherity, M; Dedovich, TG; Deppner, IM; Derevschikov, AA; Didenko, L; Dong, X; Drachenberg, JL; Dunlop, JC; Edmonds, T; Elsey, N; Engelage, J; Eppley, G; Esha, R; Esumi, S; Evdokimov, O; Ewigleben, A; Eyser, O; Fatemi, R; Fazio, S; Federic, P; Fedorisin, J; Feng, CJ; Feng, Y; Filip, P; Finch, E; Fisyak, Y; Francisco, A; Fulek, L; Gagliardi, CA; Galatyuk, T; Geurts, F; Gibson, A; Gopal, K; Grosnick, D; Guryn, W; Hamad, AI; Hamed, A | Abstract: Particle production sensitive to nonfactorizable and nonperturbative processes that contribute to the underlying event associated with a high transverse momentum (pT) jet in proton+proton collisions at s=200 GeV is studied with the STAR detector. Each event is divided into three regions based on the azimuthal angle with respect to the highest-pT jet direction: In the leading jet direction ("Toward"), opposite to the leading jet ("Away"), and perpendicular to the leading jet ("Transverse"). In the Transverse region, the average charged particle density is found to be between 0.4 and 0.6 and the mean transverse momentum

Published
2020

12. Long-range collectivity in small collision-systems with two- and four-particle correlations @ STAR

Author

Roy A. Lacey

Subjects
Physics, Nuclear and High Energy Physics, Nuclear Theory, 010308 nuclear & particles physics, FOS: Physical sciences, Collision, 01 natural sciences, High Energy Physics - Experiment, Nuclear physics, Nuclear Theory (nucl-th), High Energy Physics - Phenomenology, Broad spectrum, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), 0103 physical sciences, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Scaling, Nuclear theory
Abstract

New STAR differential and integral v{2,3} measurements that explicitly account for non-flow contributions are reported for p/d/3He+Au, collisions at Roots=200 GeV. The measurements, which leverage the two-particle correlators for p/d/3He+Au and minimum-bias p+p collisions in tandem with three well-established methods of non-flow subtraction, are observed to be method-independent. For comparable multiplicities, they further indicate system-independent v2{2} and v3{2} values that are consistent with the critical role of both size (N{ch}) and the subnucleonic-fluctuations-driven eccentricities e{2,3} but are inconsistent with the notion of shape engineering in p/d/3He+Au collisions. The scaling function derived from the measurements, confirm the important role of final-state effects across a broad spectrum of collision-system sizes and energies and suggests an increase in eta/s(T,muB) for small collision-systems., Comment: Contribution to the proceedings of QM2019

Published
2020
Full Text
View/download PDF

14. Measurement of the longitudinal spin asymmetries for weak boson production in proton-proton collisions at s=510 GeV

Author

Y. K. Sun, Bernd Surrow, I. G. Alekseev, M. A. Lisa, J. C. Mei, N. Elsey, G. Eppley, Long Ma, Peifeng Liu, J. Pluta, C. A. Gagliardi, Guannan Xie, Yanfang Liu, R. Lednicky, J. Bryslawskyj, N. Chankova-Bunzarova, Skipper Kagamaster, Subhash Singha, Justin Ewigleben, J. Fedorisin, T. Nonaka, Christina Markert, A. Gibson, G. Odyniec, Mate Csanad, Anju Bhasin, O. Rusnakova, Nasim, L. C. Bland, T. Ljubicic, H. S. Matis, Hanna Paulina Zbroszczyk, B. Pawlik, L. K. Kosarzewski, Chris Perkins, Joel Anthony Mazer, Rene Bellwied, A. J. Bassill, Liang He, Alexandre Alarcon Do Passo Suaide, Lukas Holub, Bedangadas Mohanty, Isaac Upsal, J. Lauret, H. Caines, A. Quintero, A. Aparin, Jaroslav Bielcik, J. Rusnak, Z. Chang, J. M. Butterworth, S. Stanislaus, L. Kochenda, Yaping Wang, J. C. Webb, Spiros Margetis, T. Niida, A. F. Kraishan, M. Kocan, Jie Zhang, Saskia Mioduszewski, Shusu Shi, Xiaofeng Luo, F. Seck, Guo-Liang Ma, E. Shahaliev, Dingwei Zhang, A. Lebedev, W. Solyst, John Nelson, O. V. Rogachevskiy, Vitalii Okorokov, A. H. Tang, Feng-Han Chang, Muhammad Usman Ashraf, Neha Shah, L. Ruan, Pavol Federic, Alexander Vasiliev, Li Yi, M. Posik, Tetsuro Sugiura, J. L. Drachenberg, Olga Evdokimov, M. Tokarev, Yang Yang, Matthew Kelsey, Gary Westfall, Arghya Chatterjee, Xiangming Sun, Kevin Adkins, B. Huang, C. Zhong, E. C. Aschenauer, Norbert Herrmann, Chi Yang, P. Kravtsov, G. Agakishiev, D. S. Gunarathne, Kun Jiang, J. Putschke, C. Dilks, S. W. Wissink, Wen-Qing Shen, Jaroslav Adam, Kejun Kang, S. Das, S. Horvat, Jana Bielcikova, Madan M. Aggarwal, Fuqiang Wang, S. Kabana, Z. Moravcova, Jeong-Hun Lee, O. D. Tsai, A. Ogawa, D. Cebra, Nalinda Kulathunga Mudiyanselage, Xinyue Ju, S. Trentalange, Zhen Liu, L. V. Nogach, T. Todoroki, Jay Roberts, Zhenyu Ye, D. K. Mishra, X. Dong, Maria Zurek, ShinIchi Esumi, Benjamin Schweid, Manuel Calderon De La Barca Sanchez, P. Szymanski, Zhanwen Zhu, Gang Wang, Robert E. Tribble, J. H. Thomas, Yuliang Sun, T. J. Humanic, Jiangyong Jia, D. Arkhipkin, A. Hamed, N. K. Pruthi, D. N. Svirida, S. Fazio, K. Krueger, I. G. Bordyuzhin, Joseph Kwasizur, J. Engelage, D. L. Olvitt, Miroslav Simko, Ron Longacre, Mariusz Przybycien, Paul Sorensen, G. Nigmatkulov, Cheng Li, D. Kapukchyan, I. K. Yoo, Subhasis Chattopadhyay, Yicheng Feng, A. Vossen, H. H. Wieman, Xiaolong Chen, Arabinda Behera, Xiaoyu Liu, J. W. Harris, R. Witt, Yu-Gang Ma, Roli Esha, E. P. Sichtermann, W. J. Llope, G. S. Averichev, Shuai Yang, J. M. Landgraf, I. Vassiliev, J. C. Dunlop, L. Wen, Daniel Nemes, Jie Zhao, Zhongbin Xu, Jing-Han Chen, Qiye Shou, Dmitry Morozov, J. Schambach, Alexander Jentsch, Ivan Kisel, Zubayer Ahammed, M. Strikhanov, Norbert Schmitz, F. Videbæk, M. M. Mondal, C. E. Flores, E. G. Judd, D. P. Kikola, A. Attri, Wei Li, Z. Ye, Yuanjing Li, Dmitri Smirnov, B. Stringfellow, Chensheng Zhou, A. Lipiec, Lukas Kramarik, Maowu Nie, L. Zhang, P. Huo, Sooraj Krishnan Radhakrishnan, E. Finch, Chong Kim, Niseem Magdy Abdelwahab Abdelrahman, M. Sergeeva, Kishora Nayak, W. Zha, Zhigang Xiao, Jagbir Singh, T. Huang, J. Porter, Nu Xu, Raghav Kunnawalkam Elayavalli, J. Sandweiss, A. Kechechyan, Pradip Kumar Sahu, B. K. Chan, Michal Sumbera, Yifei Zhang, P. Chaloupka, Yi-Fei Xu, Derek Anderson, Janet Elizabeth Seger, Ting Lin, I. Bunzarov, O. Matonoha, M. Lomnitz, I. M. Deppner, N. G. Minaev, Catherine Tomkiel, Hank Crawford, T. Ullrich, H. Z. Huang, Yi Wang, R. Pak, Siwei Luo, Feng Liu, A. I. Hamad, Sedigheh Jowzaee, P. Filip, Dave Underwood, Rafal Sikora, Gene Van Buren, Bill Christie, Hans Georg Ritter, Declan Keane, Xinjie Huang, Joseph Adams, Prithwish Tribedy, B. K. Srivastava, Juan M. Romero, Shengli Huang, T. G. Dedovich, Isaac Mooney, Shenghui Zhang, William Jacobs, B. Schmidke, Alena Harlenderova, H. W. Ke, L. Fulek, Yang Wu, Anik Gupta, Frank Jm Geurts, T. Galatyuk, K. Meehan, Jindrich Lidrych, Yifan Hong, Song Zhang, Zebo Tang, K. Yip, Giacomo Contin, Rongrong Ma, Nihar Sahoo, Robert Licenik, Anthony Robert Timmins, Adam Ryszard Kisiel, Roland Laszlo Pinter, R. Fatemi, Todd Kinghorn, Brian Page, Ming Shao, M. Cherney, Rosi Reed, Lokesh Kumar, A. V. Brandin, Hua Pei, S. K. Tripathy, Vipul Bairathi, Irakli Chakaberia, Y. Fisyak, K. Oh, Qian Yang, Richard Daniel Majka, D. Kalinkin, S. Heppelmann, Xin Li, B. J. Summa, S. Siejka, Z. Y. Zhang, P. Seyboth, Jan Vanek, Leszek Adamczyk, S. Ramachandran, O. Eyser, Jianping Cheng, Sergei A. Voloshin, S. Vokal, Yue Liang, Wei Xie, Hal Spinka, Hao-jie Xu, Roy A. Lacey, T. Edmonds, Pengfei Wang, P. V. Shanmuganathan, D. Mallick, G. Igo, K. Kauder, A. Taranenko, F. G. Atetalla, Alexander Schmah, Lanny Ray, H. Liu, David Stewart, Jakub Kvapil, Sevil Salur, A. K. Bhati, Nikolai Smirnov, Xiaoping Zhang, L. G. Efimov, L. Didenko, Peng Liu, Wlodek Guryn, Y. Panebratsev, Saehanseul Oh, D. Grosnick, R. Aoyama, Samuel Heppelmann, B. Tu, Qinghua Xu, Maksym Zyzak, D. D. Brown, R. Seto, James Brandenburg, K. N. Barish, T. Tarnowsky, Xianglei Zhu, and A. A. Derevschikov

Subjects
Physics, Quark, Particle physics, Proton, 010308 nuclear & particles physics, Drell–Yan process, 01 natural sciences, Helicity, Pseudorapidity, 0103 physical sciences, High Energy Physics::Experiment, Production (computer science), Nuclear Experiment, 010306 general physics, Spin-½, Boson
Abstract

We report new STAR measurements of the single-spin asymmetries $A_L$ for $W^+$ and $W^-$ bosons produced in polarized proton--proton collisions at $\sqrt{s}$ = 510 GeV as a function of the decay-positron and decay-electron pseudorapidity. The data were obtained in 2013 and correspond to an integrated luminosity of 250 pb$^{-1}$. The results are combined with previous results obtained with 86 pb$^{-1}$. A comparison with theoretical expectations based on polarized lepton-nucleon deep-inelastic scattering and prior polarized proton--proton data suggests a difference between the $\bar{u}$ and $\bar{d}$ quark helicity distributions for $0.05 < x < 0.25$. In addition, we report new results for the double-spin asymmetries $A_{LL}$ for $W^\pm$, as well as $A_L$ for $Z/\gamma^*$ production and subsequent decay into electron--positron pairs.

Published
2019

15. Beam energy dependence of (anti-)deuteron production in Au + Au collisions at the BNL Relativistic Heavy Ion Collider

Author

Yang Wu, Anik Gupta, Frank Jm Geurts, T. Galatyuk, B. K. Chan, Michal Sumbera, Catherine Tomkiel, Hank Crawford, D. Mallick, Paul Sorensen, K. Meehan, D. Kalinkin, P. Chaloupka, Ting Lin, G. Igo, S. Heppelmann, Xin Li, B. J. Summa, Gary Westfall, Peng Liu, Wlodek Guryn, Z. Y. Zhang, Y. Panebratsev, Saehanseul Oh, D. Grosnick, K. Kauder, A. Taranenko, K. Yip, Siwei Luo, Zhongbin Xu, H. W. Ke, L. Fulek, D. P. Kikola, R. Aoyama, Mariusz Przybycien, Lukas Kramarik, Xiaofeng Luo, S. Ramachandran, O. Eyser, B. Stringfellow, Sooraj Krishnan Radhakrishnan, R. Fatemi, Todd Kinghorn, Long Ma, Joseph Adams, Jiangyong Jia, T. G. Dedovich, A. H. Tang, Sergei A. Voloshin, E. Finch, Maria Stefaniak, Guo-Liang Ma, Li Yi, Samuel Heppelmann, B. Tu, Ming Shao, Feng Liu, Yifan Hong, Song Zhang, Zebo Tang, Isaac Upsal, Xiangming Sun, Yanfang Liu, J. Fedorisin, Isaac Mooney, Shenghui Zhang, Benjamin Schweid, T. J. Humanic, D. Arkhipkin, W. J. Llope, I. G. Bordyuzhin, S. Vokal, Yue Liang, J. Bryslawskyj, Yi Wang, T. Nonaka, Wei Li, M. Cherney, Rosi Reed, Lokesh Kumar, Hal Spinka, Hans Georg Ritter, A. I. Hamad, William Jacobs, Sedigheh Jowzaee, Alexander Jentsch, Dave Underwood, Chris Perkins, Wei Xie, A. K. Bhati, Z. Moravcova, Robert E. Tribble, Nikolai Smirnov, Xiaoping Zhang, A. Attri, Alexander Vasiliev, Tetsuro Sugiura, Muhammad Usman Ashraf, T. Ljubicic, P. Huo, Qinghua Xu, Kejun Kang, L. V. Nogach, Hua Pei, S. K. Tripathy, N. K. Pruthi, O. D. Tsai, Xinyue Ju, Zhen Liu, S. W. Wissink, S. Kabana, E. Shahaliev, F. G. Atetalla, Prithwish Tribedy, B. K. Srivastava, Juan M. Romero, X. Zhu, Maksym Zyzak, Z. Ye, Mate Csanad, Lanny Ray, Nu Xu, Raghav Kunnawalkam Elayavalli, Nasim, Maowu Nie, P. Kravtsov, Shengli Huang, Declan Keane, A. Kechechyan, H. Liu, Hao-jie Xu, David Stewart, ShinIchi Esumi, J. C. Dunlop, L. Wen, Janet Elizabeth Seger, Roy A. Lacey, T. Edmonds, Pengfei Wang, Sevil Salur, I. M. Deppner, G. Eppley, R. Seto, E. P. Sichtermann, Rongrong Ma, I. K. Yoo, Xiaoyu Liu, M. Sergeeva, Roli Esha, Daniel Nemes, Jie Zhao, Peifeng Liu, Nalinda Kulathunga Mudiyanselage, Joel Anthony Mazer, Brian Page, Lei Zhang, Spiros Margetis, Zubayer Ahammed, Cheng Li, D. Kapukchyan, Nihar Sahoo, A. V. Brandin, Norbert Schmitz, J. Pluta, N. Chankova-Bunzarova, V. A. Okorokov, Skipper Kagamaster, Subhash Singha, Chong Kim, Yu-Gang Ma, Anju Bhasin, H. Z. Huang, Manuel Calderon De La Barca Sanchez, Gang Wang, James Brandenburg, K. N. Barish, Christina Markert, Rafal Sikora, Guannan Xie, Chensheng Zhou, R. Bellwied, E. G. Judd, Takafumi Niida, Vipul Bairathi, Liang He, Robert Licenik, Anthony Robert Timmins, Adam Ryszard Kisiel, R. Lednicky, L. C. Bland, A. Lipiec, Yi-Fei Xu, M. Tokarev, Yang Yang, Matthew Kelsey, Feng-Han Chang, Qian Yang, Roland Laszlo Pinter, Hanna Paulina Zbroszczyk, H. S. Matis, D. Tlusty, A. Lebedev, R. Pak, T. Tarnowsky, T. Ullrich, Richard Daniel Majka, D. N. Svirida, J. L. Drachenberg, Olga Evdokimov, A. Hamed, Kun Jiang, A. A. Derevschikov, Jay Roberts, J. Porter, P. Szymanski, Maria Zurek, Dingwei Zhang, L. K. Kosarzewski, Lukas Holub, Bedangadas Mohanty, F. Videbæk, Tong Liu, H. H. Wieman, Arghya Chatterjee, K. Krueger, Yicheng Feng, R. Witt, Joseph Kwasizur, J. Lauret, Neha Shah, Jaroslav Adam, Jeong-Hun Lee, L. Didenko, I. Chakaberia, Yaping Wang, C. Zhong, Yevheniia Khyzhniak, S. Stanislaus, L. Kochenda, Xiaolong Chen, Miroslav Simko, Ron Longacre, Yuanjing Ji, J. Engelage, Alexandre Alarcon Do Passo Suaide, Arabinda Behera, X. Dong, Jing-Han Chen, Qiye Shou, J. W. Harris, Yifei Zhang, Shuai Yang, J. M. Landgraf, J. Schambach, Dmitry Morozov, Diana Pawlowska, Norbert Herrmann, J. Putschke, M. Strikhanov, H. Caines, A. Ogawa, J. Sandweiss, Kishora Nayak, J. Rusnak, Subhasis Chattopadhyay, M. Kocan, L. Ruan, I. Bunzarov, O. Matonoha, Jana Bielcikova, P. Filip, Gene Van Buren, Bill Christie, I. Vassiliev, Niseem Magdy Abdelwahab Abdelrahman, Zhigang Xiao, Jagbir Singh, T. Huang, Derek Anderson, N. G. Minaev, I. G. Alekseev, M. A. Lisa, G. Agakishiev, S. Horvat, D. Cebra, S. Trentalange, Zhanwen Zhu, Justin Ewigleben, G. Odyniec, J. C. Webb, W. Solyst, Madan M. Aggarwal, Fuqiang Wang, D. K. Mishra, Ivan Kisel, Y. K. Sun, Bernd Surrow, N. Elsey, J. H. Thomas, Yuliang Sun, C. A. Gagliardi, Jaroslav Bielcik, Yuanjing Li, G. S. Averichev, O. V. Rogachevskiy, Saskia Mioduszewski, Shusu Shi, F. Seck, M. Posik, S. Siejka, P. Seyboth, Jan Vanek, P. Federic, Jianping Cheng, Y. Fisyak, and K. Oh

Subjects
Physics, 010308 nuclear & particles physics, Equation of state (cosmology), 01 natural sciences, REAÇÕES NUCLEARES, Nuclear physics, Baryon, Deuterium, 0103 physical sciences, Transverse momentum, Quark–gluon plasma, Production (computer science), 010306 general physics, Relativistic Heavy Ion Collider, Beam energy
Abstract

Author(s): Adam, J; Adamczyk, L; Adams, JR; Adkins, JK; Agakishiev, G; Aggarwal, MM; Ahammed, Z; Alekseev, I; Anderson, DM; Aoyama, R; Aparin, A; Arkhipkin, D; Aschenauer, EC; Ashraf, MU; Atetalla, F; Attri, A; Averichev, GS; Bairathi, V; Barish, K; Bassill, AJ; Behera, A; Bellwied, R; Bhasin, A; Bhati, AK; Bielcik, J; Bielcikova, J; Bland, LC; Bordyuzhin, IG; Brandenburg, JD; Brandin, AV; Bryslawskyj, J; Bunzarov, I; Butterworth, J; Caines, H; Calderon De La Barca Sanchez, M; Cebra, D; Chakaberia, I; Chaloupka, P; Chan, BK; Chang, FH; Chang, Z; Chankova-Bunzarova, N; Chatterjee, A; Chattopadhyay, S; Chen, JH; Chen, X; Cheng, J; Cherney, M; Christie, W; Crawford, HJ; Csanad, M; Das, S; Dedovich, TG; Deppner, IM; Derevschikov, AA; Didenko, L; Dilks, C; Dong, X; Drachenberg, JL; Dunlop, JC; Edmonds, T; Elsey, N; Engelage, J; Eppley, G; Esha, R; Esumi, S; Evdokimov, O; Ewigleben, J; Eyser, O; Fatemi, R; Fazio, S; Federic, P; Fedorisin, J; Feng, Y; Filip, P; Finch, E; Fisyak, Y; Fulek, L; Gagliardi, CA; Galatyuk, T; Geurts, F; Gibson, A; Grosnick, D; Gupta, A; Guryn, W | Abstract: We report the energy dependence of mid-rapidity (anti-)deuteron production in Au+Au collisions at sNN=7.7, 11.5, 14.5, 19.6, 27, 39, 62.4, and 200 GeV, measured by the STAR experiment at the BNL Relativistic Heavy Ion Collider. The yield of deuterons is found to be well described by the thermal model. The collision energy, centrality, and transverse momentum dependence of the coalescence parameter B2 are discussed. We find that the values of B2 for antideuterons are systematically lower than those for deuterons, indicating that the correlation volume of antibaryons is larger than that of baryons at sNN from 19.6 to 39 GeV. In addition, values of B2 are found to vary with collision energy and show a broad minimum around sNN=20-40 GeV, which might imply a change of the equation of state of the medium in these collisions.

Published
2019

16. Examination of the observability of a chiral magnetically driven charge-separation difference in collisions of the Ru4496+Ru4496 and Zr4096+Zr4096 isobars at energies available at the BNL Relativistic Heavy Ion Collider

Author

Niseem Magdy, Jinfeng Liao, Shuzhe Shi, P. Liu, and Roy A. Lacey

Subjects
Physics, 010308 nuclear & particles physics, Charge separation, 0103 physical sciences, Isobar, Isobaric process, Atomic physics, Magnetic effect, Nuclear Experiment, 010306 general physics, Relativistic Heavy Ion Collider, 01 natural sciences
Abstract

Anomalous Viscous Fluid Dynamics (AVFD) model calculations for $\mathrm{^{96}_{44}Ru +\, ^{96}_{44}Ru}$ and $\mathrm{^{96}_{40}Zr +\, ^{96}_{40}Zr}$ collisions ($\sqrt{s_{\rm NN}} = 200$ GeV) are used in concert with a charge-sensitive correlator, to test its ability to detect and characterize the charge separation difference expected from the Chiral Magnetic Effect (CME) in these isobaric collisions. The tests indicate a larger charge separation for $\mathrm{^{96}_{44}Ru +\, ^{96}_{44}Ru}$ than for $\mathrm{^{96}_{40}Zr +\, ^{96}_{40}Zr}$ collisions, and a discernible CME-driven difference of $\sim 10$\% in the presence of realistic non-CME backgrounds. They also indicate a strategy for evaluating the relative influence of the background correlations, present for each isobar. These results suggest that charge separation measurements for these isobaric species could serve to further constrain unambiguous identification and characterization of the CME in upcoming measurements at RHIC.

Published
2018

17. An extended RΨm(2)(ΔS2) correlator for detecting and characterizing the Chiral Magnetic Wave

Author

Guo-Liang Ma, Niseem Magdy, M. Nie, Ling Huang, and Roy A. Lacey

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Charge separation, 0103 physical sciences, Quadrupole, Sensitivity (control systems), 010306 general physics, 01 natural sciences, Molecular physics, Nuclear theory
Abstract

The extended R Ψ m ( 2 ) ( Δ S 2 ) correlator is presented and examined for its efficacy to detect and characterize the quadrupole charge separation ( Δ S 2 ) associated with the purported Chiral Magnetic Wave (CMW) produced in heavy-ion collisions. Sensitivity tests involving varying degrees of charge separation injected into events simulated with the Multi-Phase Transport Model (AMPT) show that the R Ψ m ( 2 ) ( Δ S 2 ) correlators provide discernible responses for the background- and signal-driven quadrupole charge separation. This distinction could help identify CMW-induced quadrupole charge separation via measurements of the R Ψ 2 ( 2 ) ( Δ S 2 ) and R Ψ 3 ( 2 ) ( Δ S 2 ) correlators, relative to the second- ( Ψ 2 ) and third-order ( Ψ 3 ) event planes. The tests also indicate a sensitivity level that would allow for robust experimental characterization of possible CMW-induced charge separation.

Published
2020

18. System-size dependence of the viscous attenuation of anisotropic flow in p + Pb and Pb + Pb collisions at energies available at the CERN Large Hadron Collider

Author

Roy A. Lacey and P. Liu

Subjects
Physics, Large Hadron Collider, 010308 nuclear & particles physics, Attenuation, Shear viscosity, High Energy Physics::Phenomenology, Hadron, 01 natural sciences, 0103 physical sciences, Anisotropic flow, Atomic physics, Multiplicity (chemistry), 010306 general physics, Size dependence, Dimensionless quantity
Abstract

The elliptic and triangular flow coefficients (${v}_{n},\phantom{\rule{0.28em}{0ex}}n=2,3$) measured in Pb + Pb ($\sqrt{{s}_{{}_{\mathrm{NN}}}}=2.76\phantom{\rule{0.28em}{0ex}}\mathrm{TeV}$) and $p+\mathrm{Pb}\phantom{\rule{0.28em}{0ex}}(\sqrt{{s}_{{}_{\mathrm{NN}}}}=5.02\phantom{\rule{0.28em}{0ex}}\mathrm{TeV}$) collisions are studied as a function of initial-state eccentricity (${\ensuremath{\varepsilon}}_{n}$) and dimensionless size characterized by the cube root of the midrapidity charged hadron multiplicity density ${\ensuremath{\langle}{N}_{\mathrm{ch}}\ensuremath{\rangle}}^{1/3}$. The results indicate that the influence of eccentricity (${v}_{n}\ensuremath{\propto}{\ensuremath{\varepsilon}}_{n}$) observed for large $\ensuremath{\langle}{N}_{\mathrm{ch}}\ensuremath{\rangle}$ is superseded by the effects of viscous attenuation for small $\ensuremath{\langle}{N}_{\mathrm{ch}}\ensuremath{\rangle}$, irrespective of the colliding species. Strikingly similar acoustic scaling patterns of exponential viscous modulation with a damping rate proportional to ${n}^{2}$ and inversely proportional to the dimensionless size are observed for the eccentricity-scaled coefficients for the two sets of colliding species. The resulting scaling parameters suggest that, contrary to current predilections, the patterns of viscous attenuation as well as the specific shear viscosity $\ensuremath{\langle}\frac{\ensuremath{\eta}}{s}(T)\ensuremath{\rangle}$ for the matter created in $p+\mathrm{Pb}$ and Pb + Pb collisions are comparable.

Published
2018

19. Azimuthal anisotropy in Cu+Au collisions at sNN=200 GeV

Author

D. L. Olvitt, Isaac Upsal, James Brandenburg, J. Bryslawskyj, T. Nonaka, K. N. Barish, Subhasis Chattopadhyay, Joseph Kwasizur, T. Tarnowsky, Giacomo Contin, A. Aparin, Xianglei Zhu, Rongrong Ma, Alexander Vasiliev, Lanny Ray, Tetsuro Sugiura, P. V. Shanmuganathan, A. A. Derevschikov, Nihar Sahoo, C. Dilks, D. Mallick, Y. Pandit, Zillay Khan, X. C. Chen, Feng Liu, G. Igo, H. Liu, S. Kabana, F. Videbæk, E. Shahaliev, I. G. Bordyuzhin, Yuanjing Li, L. Krauth, M. Tokarev, Yang Yang, David Stewart, Jana Bielcikova, J. Engelage, Anthony Robert Timmins, Adam Ryszard Kisiel, Qinghua Xu, Maksym Zyzak, R. Seto, L. Zhang, Keith Landry, Hans Georg Ritter, P. Seyboth, Sevil Salur, G. Nigmatkulov, K. Kauder, A. Taranenko, L. Didenko, I. Chakaberia, Bedangadas Mohanty, Yang Wu, Anik Gupta, A. I. Hamad, A. Harlenderova, Jiro Fujita, Sedigheh Jowzaee, R. Fatemi, Xinjie Huang, Paul Sorensen, Gerrit Jan van Nieuwenhuizen, Yifei Zhang, Zachariah Miller, Abdel Nasser Tawfik, Chris Perkins, J. M. Landgraf, Ming Shao, Frank Jm Geurts, Prithwish Tribedy, B. K. Srivastava, Dmitry Morozov, Dave Underwood, Long Ma, Zhongbin Xu, J. L. Romero, M. Lomnitz, M. Strikhanov, Nu Xu, Jing-Han Chen, H. H. Wieman, Christina Markert, O. Rusnakova, Janet Elizabeth Seger, Declan Keane, Wei Li, Niseem Magdy Abdelwahab Abdelrahman, I. M. Deppner, M. Cherney, Rosi Reed, Lokesh Kumar, J. L. Drachenberg, Michal Sumbera, H. S. Matis, D. P. Kikola, B. Stringfellow, J. Sandweiss, P. Federic, Olga Evdokimov, Barbara Antonina Trzeciak, L. K. Kosarzewski, Kun Jiang, S. K. Tripathy, Jay Roberts, Yanfang Liu, Hank Crawford, Prabhat Bhattarai, J. Fedorisin, B. Pawlik, Jianping Cheng, E. Finch, Anju Bhasin, Daniel Brown, A. K. Bhati, Nasim, Xiaofeng Luo, Guo-Liang Ma, K. Meehan, Jindrich Lidrych, Zhenyu Ye, T. Niida, Nikolai Smirnov, Xiaoping Zhang, A. Lebedev, L. Adamczyk, Zhigang Xiao, T. Huang, Derek Anderson, K. Krueger, Hal Spinka, Grant Webb, Xu Sun, Alexandre Alarcon Do Passo Suaide, J. Lauret, Spiros Margetis, Martin Kocmanek, S. Stanislaus, L. Kochenda, D. Tlusty, Zhaozhong Shi, J. W. Harris, Gary Westfall, Li Yi, A. S. Hirsch, P. Kravtsov, L. G. Efimov, A. M. Schmah, Arghya Chatterjee, N. G. Minaev, R. Witt, Yi Guo, Manuel Calderon De La Barca Sanchez, Gang Wang, J. C. Dunlop, L. Wen, Kevin Adkins, John Campbell, Song Zhang, Zebo Tang, T. K. Nayak, S. B. Nurushev, S. Fazio, P. Federicova, Zubayer Ahammed, Norbert Schmitz, Jeong-Hun Lee, Robert E. Tribble, Zhao Feng, N. Kulathunga, S. Das, P. Filip, Norbert Herrmann, Wlodek Guryn, Y. Panebratsev, D. Grosnick, I. K. Yoo, Miroslav Simko, Ron Longacre, I. Bunzarov, Mariusz Przybycien, Cheng Li, D. Kapukchyan, J. Putschke, Roli Esha, R. Aoyama, Daniel Nemes, Jie Zhao, Z. Ye, A. Ogawa, Shuai Yang, Gene Van Buren, Y. Fisyak, Samuel Heppelmann, B. Tu, Q. Y. Shou, Yi-Fei Xu, Maowu Nie, M. M. Mondal, K. Oh, C. E. Flores, E. G. Judd, J. Schambach, Bill Christie, A. Kechechyan, W. Zha, Xiaozhi Bai, J. Porter, Pradip Kumar Sahu, Wen-Qing Shen, R. Pak, Jiangyong Jia, Xiaolong Chen, Arabinda Behera, J. Rusnak, A. F. Kraishan, L. Ruan, T. Todoroki, Long Zhou, Chong Kim, H. Z. Huang, Rafal Sikora, Jonathan Bouchet, Martin Girard, Jochen Mathias Thaeder, Mustafa M. Mustafa, B. Schmidke, H. W. Ke, L. Fulek, L. C. Bland, Katarzyna Poniatowska, Chi Yang, D. N. Svirida, T. G. Dedovich, H. Pei, N. Yu, E. P. Sichtermann, Kejun Kang, L. V. Nogach, Chensheng Zhou, Peifeng Liu, T. Ullrich, Yi Wang, Liang He, Neha Shah, C. Zhong, E. C. Aschenauer, X. Dong, T. Ljubicic, H. Caines, A. Quintero, Nuggehalli Ajitanand, Dmitri Smirnov, P. Chaloupka, Ting Lin, Muhammad Usman Ashraf, A. Gibson, O. D. Tsai, V. A. Okorokov, A. H. Tang, Benjamin Schweid, T. J. Humanic, D. Arkhipkin, A. Hamed, M. Sergeeva, Siwei Luo, Joseph Adams, Shenghui Zhang, William Jacobs, Jian Deng, G. Eppley, G. Agakishiev, D. S. Gunarathne, S. Horvat, J. Pluta, D. Cebra, S. Trentalange, Brian Page, Zhanwen Zhu, N. Chankova-Bunzarova, A. V. Brandin, Subhash Singha, Vipul Bairathi, Justin Ewigleben, G. Odyniec, Rene Bellwied, Qian Yang, Richard Daniel Majka, K. Yip, John Nelson, Xiangming Sun, B. Huang, J. M. Butterworth, J. H. Thomas, Arthur M. Poskanzer, Miroslav Saur, J. C. Webb, Jaroslav Bielcik, Jordan Roth, N. K. Pruthi, Jie Zhang, J. Kvapil, O. V. Rogachevskiy, W. Solyst, Sanshiro Mizuno, Y. K. Sun, Bernd Surrow, N. Elsey, D. Mayes, I. G. Alekseev, C. A. Gagliardi, M. A. Lisa, J. C. Mei, G. S. Averichev, Madan M. Aggarwal, Fuqiang Wang, D. K. Mishra, A. Vossen, Ivan Kisel, Thorsten Sven Kollegger, D. Kalinkin, Z. Chang, Yaping Wang, Saskia Mioduszewski, Shusu Shi, S. Heppelmann, Xin Li, B. J. Summa, M. Posik, Z. Y. Zhang, Michael Skoby, J. E. Draper, S. Ramachandran, O. Eyser, Sergei A. Voloshin, S. Vokal, Wei Xie, Matthew Rehbein, Roy A. Lacey, W. J. Llope, Alexander Jentsch, A. Attri, P. Huo, Guannan Xie, R. Lednicky, Hanna Paulina Zbroszczyk, Ji Xu, Jingbo Zhang, S. W. Wissink, ShinIchi Esumi, and Yu-Gang Ma

Subjects
Physics, Range (particle radiation), 010308 nuclear & particles physics, media_common.quotation_subject, 01 natural sciences, Asymmetry, Charged particle, Pseudorapidity, Electric field, 0103 physical sciences, Rapidity, Center of mass, Atomic physics, Nuclear Experiment, 010306 general physics, Anisotropy, media_common
Abstract

The azimuthal anisotropic flow of identified and unidentified charged particles has been systematically studied in Cu+Au collisions at sNN=200 GeV for harmonics n=1–4 in the pseudorapidity range |η

Published
2018

20. Global polarization of Λ hyperons in Au + Au collisions at sNN=200 GeV

Author

Chensheng Zhou, T. Ullrich, Yi Wang, T. Ljubicic, H. Caines, Neha Shah, C. Zhong, X. Dong, Jeong-Hun Lee, Miroslav Simko, Ron Longacre, A. Harlenderova, Long Ma, Justin Ewigleben, G. Odyniec, Shuai Yang, Chris Perkins, Yanfang Liu, J. Schambach, J. Fedorisin, Anju Bhasin, A. J. Bassill, Xiaofeng Luo, Guo-Liang Ma, J. C. Webb, Roli Esha, Jaroslav Bielcik, Li Yi, T. Niida, W. Solyst, Daniel Nemes, Jie Zhao, H. W. Ke, L. Fulek, Jie Zhang, A. S. Hirsch, A. Lebedev, L. C. Bland, Alexandre Alarcon Do Passo Suaide, P. Kravtsov, A. M. Schmah, A. Lipiec, O. V. Rogachevskiy, I. G. Alekseev, M. A. Lisa, J. C. Mei, J. Porter, Arghya Chatterjee, Feng-Han Chang, D. N. Svirida, Ivan Kisel, D. L. Olvitt, Gary Westfall, J. Kvapil, G. Agakishiev, D. S. Gunarathne, Long Zhou, Subhasis Chattopadhyay, S. Horvat, D. Cebra, S. Trentalange, Zhanwen Zhu, Chong Kim, Y. K. Sun, Bernd Surrow, Brian Page, S. Siejka, Nu Xu, H. Z. Huang, A. V. Brandin, N. Elsey, D. Mayes, Janet Elizabeth Seger, Daniel Brown, Hal Spinka, I. M. Deppner, F. Videbæk, Norbert Herrmann, Rafal Sikora, Yuanjing Li, J. Rusnak, Zhongbin Xu, A. F. Kraishan, Vipul Bairathi, L. Zhang, L. Ruan, J. L. Romero, C. A. Gagliardi, J. Putschke, Yifei Zhang, Qian Yang, Richard Daniel Majka, Lukas Kramarik, T. Todoroki, Jana Bielcikova, Madan M. Aggarwal, Sooraj Krishnan Radhakrishnan, Fuqiang Wang, E. Finch, P. Federicova, J. H. Thomas, A. Ogawa, M. Tokarev, Yang Yang, K. Yip, D. K. Mishra, N. Kulathunga, J. L. Drachenberg, Yang Wu, Anik Gupta, P. Szymanski, P. Filip, H. H. Wieman, I. G. Bordyuzhin, Y. Fisyak, Olga Evdokimov, K. Oh, Muhammad Usman Ashraf, Xiangming Sun, D. Mallick, Frank Jm Geurts, B. Huang, A. Vossen, D. Kalinkin, T. Galatyuk, Gene Van Buren, O. D. Tsai, Z. Ye, Manuel Calderon De La Barca Sanchez, L. Didenko, I. Chakaberia, Cheng Li, D. Kapukchyan, G. Igo, Maowu Nie, L. Krauth, S. Heppelmann, A. Kechechyan, James Brandenburg, K. N. Barish, Xin Li, B. J. Summa, Fuwang Shen, Gang Wang, G. S. Averichev, Christina Markert, Bill Christie, K. Kauder, A. Taranenko, O. Rusnakova, P. Seyboth, Xiaozhi Bai, Jaroslav Adam, K. Meehan, S. B. Nurushev, J. Bryslawskyj, Z. Y. Zhang, T. Tarnowsky, H. S. Matis, T. Nonaka, Jindrich Lidrych, Jiangyong Jia, L. K. Kosarzewski, Xiaolong Chen, J. Lauret, Xianglei Zhu, Arabinda Behera, Kun Jiang, Jay Roberts, Song Zhang, Yaping Wang, A. A. Derevschikov, A. I. Hamad, Saskia Mioduszewski, Shusu Shi, Zebo Tang, Sedigheh Jowzaee, S. Stanislaus, L. Kochenda, Jan Vanek, Joseph Kwasizur, Dave Underwood, N. K. Pruthi, Qinghua Xu, F. Seck, Maksym Zyzak, E. Shahaliev, Declan Keane, K. Krueger, P. Federic, M. Sergeeva, I. Vassiliev, M. Posik, Jianping Cheng, G. Eppley, O. Eyser, Sergei A. Voloshin, J. W. Harris, R. Seto, Siwei Luo, J. Pluta, W. J. Llope, Wei Li, R. Witt, N. Chankova-Bunzarova, I. Bunzarov, O. Matonoha, Subhash Singha, Joseph Adams, Alexander Jentsch, Niseem Magdy Abdelwahab Abdelrahman, Zhigang Xiao, T. Huang, J. C. Dunlop, L. Wen, Rene Bellwied, S. Vokal, Yue Liang, Wei Xie, A. Attri, Wlodek Guryn, Y. Panebratsev, Isaac Mooney, Shenghui Zhang, Zubayer Ahammed, Norbert Schmitz, Derek Anderson, P. Huo, Saehanseul Oh, D. Grosnick, William Jacobs, N. G. Minaev, John Campbell, S. W. Wissink, Q. Y. Shou, Yi-Fei Xu, Sumit Kumar, R. Pak, Feng Liu, Roy A. Lacey, Hans Georg Ritter, R. Aoyama, Mariusz Przybycien, ShinIchi Esumi, Prithwish Tribedy, B. K. Srivastava, Shengli Huang, Samuel Heppelmann, Peifeng Liu, B. Tu, Yu-Gang Ma, Guannan Xie, R. Lednicky, Hanna Paulina Zbroszczyk, A. K. Bhati, Nikolai Smirnov, Xiaoping Zhang, Xu Sun, L. G. Efimov, Liang He, Ji Xu, F. G. Atetalla, Lanny Ray, H. Liu, David Stewart, Sevil Salur, T. G. Dedovich, H. Pei, N. Yu, Kejun Kang, L. V. Nogach, Isaac Upsal, Alexander Vasiliev, Tetsuro Sugiura, S. Kabana, Paul Sorensen, D. P. Kikola, B. Stringfellow, R. Fatemi, Todd Kinghorn, Ming Shao, M. Cherney, Rosi Reed, Lokesh Kumar, S. K. Tripathy, Rongrong Ma, Nihar Sahoo, X. C. Chen, Anthony Robert Timmins, Adam Ryszard Kisiel, J. Engelage, J. M. Landgraf, Dmitry Morozov, M. Strikhanov, J. Sandweiss, Nasim, Joel Anthony Mazer, Spiros Margetis, D. Tlusty, S. Das, Jing-Han Chen, Michal Sumbera, Catherine Tomkiel, Hank Crawford, P. Chaloupka, Ting Lin, A. H. Tang, Benjamin Schweid, T. J. Humanic, D. Arkhipkin, A. Hamed, Jesus Negrete, V. A. Okorokov, Lukas Holub, Bedangadas Mohanty, Robert E. Tribble, I. K. Yoo, M. M. Mondal, E. G. Judd, and E. P. Sichtermann

Subjects
Physics, 010308 nuclear & particles physics, media_common.quotation_subject, Hyperon, Vorticity, Polarization (waves), Lambda, 01 natural sciences, Asymmetry, Magnetic field, Nuclear physics, Pseudorapidity, 0103 physical sciences, High Energy Physics::Experiment, Rapidity, Nuclear Experiment, 010306 general physics, media_common
Abstract

Global polarization of $\Lambda$ hyperons has been measured to be of the order of a few tenths of a percent in Au+Au collisions at $\sqrt{s_{_{NN}}}$ = 200 GeV, with no significant difference between $\Lambda$ and $\bar{\Lambda}$. These new results reveal the collision energy dependence of the global polarization together with the results previously observed at $\sqrt{s_{_{NN}}}$ = 7.7 -- 62.4 GeV and indicate noticeable vorticity of the medium created in non-central heavy-ion collisions at the highest RHIC collision energy. The signal is in rough quantitative agreement with the theoretical predictions from a hydrodynamic model and from the AMPT (A Multi-Phase Transport) model. The polarization is larger in more peripheral collisions, and depends weakly on the hyperon's transverse momentum and pseudorapidity $\eta^H$ within $|\eta^H

Published
2018

21. Scaling Properties of the Mean Multiplicity and Pseudorapidity Density in e−+e+, e±+p, p( p ¯ )+p, p+A and A+A(B) Collisions

Author

Pak, Roy A. Lacey, Peifeng Liu, Niseem Magdy, Máté Csanád, Benjamin Schweid, Nuggehalli N. Ajitanand, John Alexander, and Robert

Subjects
multiplicity scaling, leading particle effect, effective energy, participant scaling
Abstract

The charged-particle pseudorapidity density ( d N ch / d η ) for p( p ¯ )+p, p+A and A+A(B) collisions and the mean multiplicity 〈 N ch 〉 for e − +e + , e ± + p , and p( p ¯ )+p collisions are studied for a wide range of beam energies ( s ). Characteristic scaling patterns are observed for both d N ch / d η and 〈 N ch 〉 , consistent with a thermal particle production mechanism for the bulk of the soft particles created in all of these systems. The scaling patterns found also validate an essential role for quark participants in these collisions. The measured values for d N ch / d η and 〈 N ch 〉 are observed to factorize into contributions that depend on log ( s ) and the number of nucleon or quark participant pairs N pp . The quantification of these contributions gives expressions that serve to systematize d N ch / d η and 〈 N ch 〉 measurements spanning nearly 4 orders of magnitude in s and to predict their values as a function of s and N pp .

Published
2018
Full Text
View/download PDF

22. Scaling Properties of the Mean Multiplicity and Pseudorapidity Density in e+e-, e+p, p+p, p+A and A+A(B) Collisions

Author

Roy, A Lacey, Peifeng, Liu, Niseem, Magdy, Máté, Csanád, Benjamin, Schweid, Nuggehalli, N Ajitanand, John, Alexander, and Robert, Pak

Subjects
High Energy Physics::Experiment, Nuclear Experiment
Abstract

The charged-particle pseudorapidity density (dN(ch)/d eta) for p((p) over bar)+p, p+A and A+A(B) collisions and the mean multiplicity < N-ch > for e(-)+e(+), e(+/-)+p, and p((p) over bar)+p collisions are studied for a wide range of beam energies (root s). Characteristic scaling patterns are observed for both dN(ch)/d eta and < N-ch >, consistent with a thermal particle production mechanism for the bulk of the soft particles created in all of these systems. The scaling patterns found also validate an essential role for quark participants in these collisions. The measured values for dN(ch)/d eta and < N-ch > are observed to factorize into contributions that depend on log (root s) and the number of nucleon or quark participant pairs N-pp. The quantification of these contributions gives expressions that serve to systematize dN(ch)/d eta and < N-ch > measurements spanning nearly 4 orders of magnitude in root s and to predict their values as a function of root s and N-pp.

Published
2018

23. Erratum to: Extracting kinetic freeze-out temperature and radial flow velocity from an improved Tsallis distribution

Author

Fu-Hu Liu, Roy A. Lacey, and Hai-Ling Lao

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, 010308 nuclear & particles physics, Hadron, Kinetic energy, 01 natural sciences, Nuclear physics, Isospin, 0103 physical sciences, Tsallis distribution, Impact parameter, Nuclear Experiment, 010306 general physics, Relativistic Heavy Ion Collider, Nucleon, Energy (signal processing)
Abstract

We analyze the transverse-momentum (pT) spectra of identified particles ( $\pi^{\pm}$ , $K^{\pm}$ , p, and $\bar{p}$ ) produced in gold-gold (Au-Au) and lead-lead (Pb-Pb) collisions over a $\sqrt{s_{NN}}$ (center-of-mass energy per nucleon pair) range from 14.5 GeV (one of the Relativistic Heavy Ion Collider (RHIC) energies) to 2.76 TeV (one of the Large Hadron Collider (LHC) energies). For the spectra with a narrow pT range, an improved Tsallis distribution which is in fact the Tsallis distribution with radial flow is used. For the spectra with a wide pT range, a superposition of the improved Tsallis distribution and an inverse power law is used. Both the extracted kinetic freeze-out temperature (T0) and radial flow velocity ( $\beta_{T}$ ) increase with the increase of $\sqrt{s_{NN}}$ , which indicates a higher excitation and larger expansion of the interesting system at the LHC. Both the values of T0 and $\beta_{T}$ in central collisions are slightly larger than those in peripheral collisions, and they are independent of isospin and slightly dependent on mass.

Published
2017

24. Examining the model dependence of the determination of kinetic freeze-out temperature and transverse flow velocity in small collision system

Author

Roy A. Lacey, Bao-Chun Li, Hai-Ling Lao, Mai-Ying Duan, and Fu-Hu Liu

Subjects
Nuclear and High Energy Physics, Nuclear Theory, Physics::Instrumentation and Detectors, FOS: Physical sciences, Kinetic energy, 01 natural sciences, High Energy Physics - Experiment, law.invention, Nuclear physics, Nuclear Theory (nucl-th), High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), law, 0103 physical sciences, Nuclear Experiment (nucl-ex), 010306 general physics, Collider, Nuclear Experiment, Physics, Large Hadron Collider, Solenoidal vector field, 010308 nuclear & particles physics, Collision, High Energy Physics - Phenomenology, Transverse plane, Nuclear Energy and Engineering, Flow velocity, Relativistic Heavy Ion Collider
Abstract

The transverse momentum distributions of the identified particles produced in small collision systems at the Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) have been analyzed by four models. The first two models utilize the blast-wave model with different statistics. The last two models employ certain linear correspondences based on different distributions. The four models describe the experimental data measured by the Pioneering High Energy Nuclear Interaction eXperiment (PHENIX), Solenoidal Tracker at RHIC (STAR), and A Large Ion Collider Experiment (ALICE) cCollaborations equally well. It is found that both the kinetic freeze-out temperature and transverse flow velocity in the central collisions are comparable with those in the peripheral collisions. With the increase of collision energy from that of the RHIC to that of the LHC, the considered quantities typically do not decrease. Comparing with the central collisions, the proton-proton collisions are closer to the peripheral collisions., Comment: 17 pages, 9 figures. Nuclear Science and Techniques, Accepted. arXiv admin note: text overlap with arXiv:1703.04944

Published
2017
Full Text
View/download PDF

25. Event Patterns Extracted from Transverse Momentum and Rapidity Spectra of Bosons and Quarkonium States Produced in pp and Pb-Pb Collisions at LHC

Author

Ya-Hui Chen, Fu-Hu Liu, and Roy A. Lacey

Subjects
Nuclear and High Energy Physics, Meson, Nuclear Theory, Article Subject, FOS: Physical sciences, 01 natural sciences, Spectral line, High Energy Physics - Experiment, Nuclear physics, Nuclear Theory (nucl-th), High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), 0103 physical sciences, Rapidity, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Boson, Physics, Large Hadron Collider, 010308 nuclear & particles physics, High Energy Physics::Phenomenology, Quarkonium, lcsh:QC1-999, High Energy Physics - Phenomenology, High Energy Physics::Experiment, Nucleon, Event (particle physics), lcsh:Physics
Abstract

Transverse momentum ($p_T$) and rapidity ($y$) spectra of $Z$ bosons and quarkonium states (some charmonium $c\bar c$ mesons such as $J/\psi$ and $\psi(2S)$, and some bottomonium $b\bar b$ mesons such as $\Upsilon(1S)$, $\Upsilon(2S)$, and $\Upsilon(3S)$) produced in proton-proton ($pp$) and lead-lead (Pb-Pb) collisions at the large hadron collider (LHC) are uniformly described by a hybrid model of two-component Erlang distribution for $p_T$ spectrum and two-component Gaussian distribution for $y$ spectrum. The former distribution results from a multisource thermal model, and the latter one results from the revised Landau hydrodynamic model. The modelling results are in agreement with the experimental data measured in $pp$ collisions at center-of-mass energies $\sqrt{s}=2.76$ and 7 TeV, and in Pb-Pb collisions at center-of-mass energy per nucleon pair $\sqrt{s_{NN}}=2.76$ TeV. Based on the parameter values extracted from $p_T$ and $y$ spectra, the event patterns (particle scatter plots) in two-dimensional $p_T$-$y$ space and in three-dimensional velocity space are obtained., Comment: 22 pages, 14 figures. Advances in High Energy Physics, accepted

Published
2016

26. Excitation functions of parameters extracted from three-source (net-)proton rapidity distributions in Au-Au and Pb-Pb collisions over an energy range from AGS to RHIC

Author

Roy A. Lacey, Yan Sun, Zhu Sun, Li-Na Gao, and Fu-Hu Liu

Subjects
Nuclear and High Energy Physics, Particle physics, Proton, Nuclear Theory, FOS: Physical sciences, Alternating Gradient Synchrotron, 01 natural sciences, High Energy Physics - Experiment, Nuclear Theory (nucl-th), High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), 0103 physical sciences, Saturation (graph theory), Rapidity, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Excitation function, Physics, 010308 nuclear & particles physics, Super Proton Synchrotron, High Energy Physics - Phenomenology, High Energy Physics::Experiment, Relativistic Heavy Ion Collider, Energy (signal processing)
Abstract

Experimental results of the rapidity spectra of protons and net-protons (protons minus antiprotons) emitted in gold-gold (Au-Au) and lead-lead (Pb-Pb) collisions, measured by a few collaborations at the alternating gradient synchrotron (AGS), super proton synchrotron (SPS), and relativistic heavy ion collider (RHIC), are described by a three-source distribution. The values of the distribution width $\sigma_C$ and contribution ratio (relative contribution) $k_C$ of the central rapidity region, and the distribution width $\sigma_F$ and rapidity shift $\Delta y$ of the forward/backward rapidity regions, are then obtained. The excitation function of $\sigma_C$ increases generally with increase of the center-of-mass energy per nucleon pair $\sqrt{s_{NN}}$. The excitation function of $\sigma_F$ shows a saturation at $\sqrt{s_{NN}}=8.8$ GeV. The excitation function of $k_C$ shows a minimum at $\sqrt{s_{NN}}=8.8$ GeV and a saturation at $\sqrt{s_{NN}}\approx 17$ GeV. The excitation function of $\Delta y$ increase monotonously with $\ln \sqrt{s_{NN}}$ in the considered energy range., Comment: 19 pages, 8 figures, The European Physical Journal A, accepted

Published
2016

27. Excitation functions of parameters in Erlang distribution, Schwinger mechanism, and Tsallis statistics in RHIC BES program

Author

Fu-Hu Liu, Roy A. Lacey, and Li-Na Gao

Subjects
Physics, Nuclear and High Energy Physics, Meson, Nuclear Theory, 010308 nuclear & particles physics, Hadron, Tsallis statistics, Erlang distribution, Hyperon, FOS: Physical sciences, 01 natural sciences, Charged particle, law.invention, Nuclear Theory (nucl-th), Nuclear physics, High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), law, 0103 physical sciences, High Energy Physics::Experiment, 010306 general physics, Collider, Nuclear Experiment, Excitation
Abstract

Experimental results of the transverse momentum distributions of phi mesons and $\Omega$ hyperons produced in gold-gold (Au-Au) collisions with different centrality intervals, measured by the STAR Collaboration at different energies (7.7, 11.5, 19.6, 27, and 39 GeV) in the beam energy scan (BES) program at the relativistic heavy ion collider (RHIC), are approximately described by the single Erlang distribution and the two-component Schwinger mechanism. Meanwhile, the STAR experimental transverse momentum distributions of negatively charged particles, produced in Au-Au collisions at RHIC BES energies, are approximately described by the two-component Erlang distribution and the single Tsallis statistics. The excitation functions of free parameters are obtained from the fit to the experimental data. A weak softest point in the string tension in $\Omega$ hyperon spectra is observed at 7.7 GeV., Comment: 18 pages, 7 figures, The European Physical Journal A, accepted

Published
2016

28. Kinetic freeze-out temperature and flow velocity extracted from transverse momentum spectra of final-state light flavor particles produced in collisions at RHIC and LHC

Author

Roy A. Lacey, Fu-Hu Liu, and Hua-Rong Wei

Subjects
Physics, Nuclear and High Energy Physics, Large Hadron Collider, Nuclear Theory, 010308 nuclear & particles physics, FOS: Physical sciences, Kinetic energy, 01 natural sciences, Nuclear Theory (nucl-th), Momentum, Nuclear physics, Transverse plane, High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), Flow velocity, 0103 physical sciences, Invariant mass, Particle velocity, Nuclear Experiment (nucl-ex), 010306 general physics, Relativistic Heavy Ion Collider, Nuclear Experiment
Abstract

The transverse momentum spectra of final-state light flavor particles produced in proton-proton (p-p), copper-copper (Cu-Cu), gold-gold (Au-Au), lead-lead (Pb-Pb), and proton-lead (p-Pb) collisions for different centralities at relativistic heavy ion collider (RHIC) and large hadron collider (LHC) energies are studied in the framework of a multisource thermal model. The experimental data measured by the STAR, CMS, and ALICE Collaborations are consistent with the results calculated by the multi-component Erlang distribution and Tsallis Statistics. The effective temperature and real temperature (kinetic freeze-out temperature) of interacting system at the stage of kinetic freeze-out, the mean transverse flow velocity and mean flow velocity of particles, and the relationships between them are extracted. The dependences of effective temperature and mean (transverse) momentum on rest mass, moving mass, centrality, and center-of-mass energy, and the dependences of kinetic freeze-out temperature and mean (transverse) flow velocity on centrality, center-of-mass energy, and system size are obtained., 28 pages, 13 figures. Minor correction. The European Physical Journal A, accepted

Published
2016

29. Extracting kinetic freeze-out temperature and radial flow velocity from an improved Tsallis distribution

Author

Roy A. Lacey, Fu-Hu Liu, and Hai-Ling Lao

Subjects
Nuclear and High Energy Physics, Nuclear Theory, Inverse, FOS: Physical sciences, Kinetic energy, 01 natural sciences, High Energy Physics - Experiment, Nuclear physics, Nuclear Theory (nucl-th), High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), 0103 physical sciences, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Physics, Large Hadron Collider, 010308 nuclear & particles physics, High Energy Physics - Phenomenology, Isospin, Tsallis distribution, High Energy Physics::Experiment, Nucleon, Relativistic Heavy Ion Collider, Energy (signal processing)
Abstract

We analyze the transverse momentum ($p_T$) spectra of identified particles ($\pi^{\pm}$, $K^{\pm}$, $p$, and $\bar p$) produced in gold-gold (Au-Au) and lead-lead (Pb-Pb) collisions over a $\sqrt{s_{NN}}$ (center-of-mass energy per nucleon pair) range from 14.5 GeV [one of the Relativistic Heavy Ion Collider (RHIC) energies] to 2.76 TeV [one of the Large Hadron Collider (LHC) energies]. For the spectra with a narrow $p_T$ range, an improved Tsallis distribution which is in fact the Tsallis distribution with radial flow is used. For the spectra with a wide $p_T$ range, a superposition of the improved Tsallis distribution and an inverse power-law is used. Both the extracted kinetic freeze-out temperature ($T_0$) and radial flow velocity ($\beta_T$) increase with the increase of $\sqrt{s_{NN}}$, which indicates a higher excitation and larger expansion of the interesting system at the LHC. Both the values of $T_0$ and $\beta_T$ in central collisions are slightly larger than those in peripheral collisions, and they are independent of isospin and slightly dependent on mass., Comment: We have corrected the pseudorapidity ranges of the data quoted in this paper. The PHENIX data should be in the pseudorapidity range $|\eta

Published
2016
Full Text
View/download PDF

30. An Evidence of Mass Dependent Differential Kinetic Freeze-out Scenario Observed in Pb-Pb Collisions at 2.76 TeV

Author

Hai-Ling Lao, Roy A. Lacey, Hua-Rong Wei, and Fu-Hu Liu

Subjects
Physics, Nuclear and High Energy Physics, Nuclear Theory, 010308 nuclear & particles physics, FOS: Physical sciences, Kinetic energy, 01 natural sciences, High Energy Physics - Experiment, Nuclear physics, Nuclear Theory (nucl-th), Transverse plane, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), Flow velocity, 0103 physical sciences, Particle, Tsallis distribution, Invariant mass, Nuclear Experiment (nucl-ex), 010306 general physics, Nucleon, Nuclear Experiment, Event (particle physics)
Abstract

Transverse momentum spectra of different particles produced in mid-rapidity interval in lead-lead (Pb-Pb) collisions with different centrality intervals, measured by the ALICE Collaboration at center-of-mass energy per nucleon pair $\sqrt{s_{NN}}=2.76$ TeV, are conformably and approximately described by the Tsallis distribution. The dependences of parameters (effective temperature, entropy index, and normalization factor) on event centrality and particle rest mass are obtained. The source temperature at the kinetic freeze-out is obtained to be the intercept in the linear relation between effective temperature and particle rest mass, while the particle transverse flow velocity is approximately extracted to be the slope in the linear relation between mean transverse momentum and particle rest mass. It is shown that the source temperature increases with increase of particle rest mass, which exhibits an evidence of mass dependent differential kinetic freeze-out scenario or multiple kinetic freeze-out scenario., 15 pages, 7 figures. The European Physical Journal A, accepted

Published
2015

31. Scaling Properties of the Mean Multiplicity and Pseudorapidity Density in e−+e+, e±+p, p( p ¯ )+p, p+A and A+A(B) Collisions

Author

Mate Csanad, Benjamin Schweid, P. Liu, Nuggehalli N. Ajitanand, John M. Alexander, Roy A. Lacey, Niseem Magdy, and Robert Pak

Subjects
Physics, Quark, 010308 nuclear & particles physics, General Physics and Astronomy, Multiplicity (mathematics), Inelastic scattering, 01 natural sciences, Factorization, Pseudorapidity, 0103 physical sciences, Orders of magnitude (speed), Atomic physics, 010306 general physics, Nucleon, Scaling
Abstract

The charged-particle pseudorapidity density ( d N ch / d η ) for p( p ¯ )+p, p+A and A+A(B) collisions and the mean multiplicity 〈 N ch 〉 for e − +e + , e ± + p , and p( p ¯ )+p collisions are studied for a wide range of beam energies ( s ). Characteristic scaling patterns are observed for both d N ch / d η and 〈 N ch 〉 , consistent with a thermal particle production mechanism for the bulk of the soft particles created in all of these systems. The scaling patterns found also validate an essential role for quark participants in these collisions. The measured values for d N ch / d η and 〈 N ch 〉 are observed to factorize into contributions that depend on log ( s ) and the number of nucleon or quark participant pairs N pp . The quantification of these contributions gives expressions that serve to systematize d N ch / d η and 〈 N ch 〉 measurements spanning nearly 4 orders of magnitude in s and to predict their values as a function of s and N pp .

Published
2018

32. Correlated production of p and p¯ in Au+Au collisions at sNN=200 GeV

Author

J. Chiba, M. B. Deaton, R. A. Soltz, H. Borel, M. Grosse Perdekamp, Y. Tanaka, T. K. Shea, G. C. Mishra, Takao Sakaguchi, S. Bathe, Agneta Oskarsson, B. Love, Marie Germain, J. L. Charvet, C. R. Cleven, C. Haegemann, Y. Inoue, C. Klein-Boesing, A. D. Frawley, Y. Berdnikov, Y. Akiba, S. Afanasiev, A. Ster, I. Tserruya, A. G. Litvinenko, P. J. Kroon, T. Tabaru, M. Mishra, S. Nagamiya, Kazuhiro Tanaka, J. Newby, G. Roche, T. E. Miller, E. T. Atomssa, S. Esumi, Yu. Efremenko, V. Singh, Dong-Hun Kim, S. H. Aronson, L. Baksay, Vaclav Vrba, Klaus Johannes Reygers, Charles Maguire, P. Chung, Robert F. Hobbs, T. Hester, W. A. Zajc, V. Baublis, M. Issah, Debashish Pal, S. Sawada, A. Kozlov, W. Holzmann, J. Ying, A. Franz, S. Leckey, Josh Moss, E. Kistenev, D. Hornback, M. Heffner, A. Denisov, S. Belikov, K. S. Joo, V. Cianciolo, R. Seto, K. Haruna, M. Mitrovski, Y. L. Yamaguchi, Tadaaki Isobe, Maya Hachiya Shimomura, Y. I. Makdisi, A. Taranenko, Kazushi Miki, M. Wysocki, Sergey Fokin, M. Holmes, M. D. Malik, E. Vznuzdaev, D. Winter, M. P. Comets, D. Yu Peressounko, V. Dzhordzhadze, Hirohiko Sato, Alexei Khanzadeev, H. Harada, H. Pei, J. S. Chai, T. Horaguchi, N. Grau, K. Shoji, A. Kiss, E. Stenlund, J. L. Drachenberg, S. F. Pate, W. S. Emam, P. L. McGaughey, P. Tarján, J. M. Burward-Hoy, B. Komkov, Norio Saito, M. A. L. Leite, S. Batsouli, X. He, Y. Nakamiya, S. K. Tuli, O. O. Omiwade, K. Dehmelt, P. W. Stankus, M. J. Tannenbaum, Marisilvia Donadelli, V. Bumazhnov, Z. Yasin, Henner Buesching, H. Sakata, L. Aphecetche, H. Al-Bataineh, V. Papavassiliou, J. Egdemir, M. Chiu, T. A. Shibata, S. P. Sorensen, V. Peresedov, Y. Le Bornec, K. Hasuko, Steven E. Skutnik, Jason Kamin, M. C. McCain, G. Baksay, V-N. Tram, S. Kelly, N. N. Ajitanand, Dylan Walker, W. C. Smith, Marcus Hohlmann, Andry Malala Rakotozafindrabe, Senta Greene, D. Isenhower, D. Mukhopadhyay, S. Rembeczki, D. Sharma, Jen-Chieh Peng, K. Das, B. Forestier, Jan Rak, Hiroyuki Okada, V. Babintsev, A. P.T. Palounek, S. P. Stoll, A. Toia, L. Mašek, M. T. Bjorndal, Johannes Peter Wessels, B. E. Norman, Minghui Liu, D. Bucher, E. P. Hartouni, H. Masui, A. K. Dubey, Joakim Nystrand, G. S. Kyle, Tae-Yeon Lee, Eva Haslum, B. Lenzi, Martin Purschke, F. Gastineau, H. Qu, R. Granier de Cassagnac, M. K. Lee, Takahiro Nakamura, A. Adare, P. Rosnet, Kenneth Francis Read, Xiong Wang, A. A. Bickley, K. O. Eyser, S. S.E. Rosendahl, G. Bunce, K. Fujiwara, H. A. Gustafsson, Susumu Oda, D. Kotchetkov, T. Shohjoh, H. Kanou, Taku Gunji, H. Gong, L. Tomášek, A. Hadj Henni, A. V. Kazantsev, S. Takagi, Hideki Hamagaki, K. Aoki, G. David, T. V. Moukhanova, C. Zhang, J. Seele, James Alexander, R. Averbeck, Byung-Sik Hong, A. Durum, V. S. Pantuev, A. Bazilevsky, K. N. Barish, F. Kajihara, F. Matathias, Dong Jo Kim, A. Morreale, Osamu Jinnouchi, A. Churyn, Z. Fraenkel, P. Mikeš, Kensuke Homma, E. O'Brien, Catherine Micaela Silvestre, D. S. Brown, Motoi Inaba, J. G. Lajoie, T. Hachiya, H. Delagrange, K. Boyle, D. Jouan, Wei Xie, Yoichiro Fukao, M. Harvey, Roy A. Lacey, R. Vértesi, B. Azmoun, A. Král, M. J. Kweon, S. Chernichenko, H. Lim, Alexandre Lebedev, Viktor Riabov, T. C. Awes, D. M. Lee, B. Bassalleck, Anne Marie Sickles, Junji Tojo, D. E. Fields, S. Zhou, Kyoichiro Ozawa, T. Liška, Mate Csanad, Rushan Han, M. N. Hagiwara, Jun Kikuchi, M. Konno, B. V. Jacak, H. W. Van Hecke, C. A. Ogilvie, M. L. Brooks, I. J. Choi, A. Baldisseri, J. T. Mitchell, A. Kravitz, M. McCumber, A. K. Purwar, K. Okada, M. Oka, Hiroaki Ohnishi, Y. S. Kim, A. Dion, R. Seidl, S. Butsyk, Vladislav Manko, Christophe Pierre Suire, Alexander Milov, T. K. Hemmick, I. Nakagawa, M. Slunečka, Yasuo Miake, Vladimir Samsonov, Atsushi Taketani, A. Enokizono, I. Otterlund, B. Sahlmueller, E. H. Kim, H. En'yo, P. Constantin, M. J. Leitch, O. Drapier, Frank Ellinghaus, G. R. Young, E. R. Kinney, D. P. Morrison, L. Kochenda, N. Willis, C. Vale, T. Kawagishi, S. Campbell, B. S. Chang, Christine Angela Aidala, J. Klay, V. E. Semenov, J. Zimányi, R. Pak, Tamas Ferenc Csorgo, K. S. Sim, J. L. Nagle, Tatsuya Chujo, N. Kamihara, Y. Kwon, R. Armendariz, Xingguo Li, M. Gonin, H. Hiejima, Kazuyoshi Kurita, E. J. Desmond, T. L. Thomas, David D'Enterria, K. Imai, A. Drees, Xiao-yan Li, J. Kubart, H. Pereira, M. Togawa, J. Park, Florian Bauer, Ryugo S. Hayano, R. P. Pisani, Y. Riabov, Y. Tsuchimoto, Kenta Shigaki, M. Nguyen, I. E. Yushmanov, Nikolay Tyurin, A. S. Nyanin, M. N. Wagner, J. E. Frantz, M. Ouchida, J. Asai, Shingo Sakai, C. L. Woody, A. Shevel, D. Lynch, I. V. Sourikova, A. Glenn, V. L. Rykov, T. Dahms, I. Ravinovich, Y. Nagata, A. Deshpande, Y. Watanabe, S. S. Ryu, T. Ichihara, I. Younus, Matthew G. Reuter, A. Soldatov, D. Kawall, K. Tanida, V. I. Kochetkov, Takahiro Fusayasu, J. Murata, R. Bennett, Gerd Joachim Kunde, I. Shein, C. P. Singh, B. M. Johnson, I. D. Ojha, Alexander Malakhov, A. Isupov, Ahmed Al-Jamel, M. Finger, J. Sziklai, D. Silvermyr, Brian Cole, M. Naglis, L. S. Zolin, C. L. Silva, Saskia Mioduszewski, W. J. Park, Masayasu Ishihara, O. Zaudtke, Susumu Sato, F. Staley, M. Virius, P. D. Barnes, A. Yanovich, J. Jin, E. M. Takagui, R. S. Towell, S. Y. Fung, I. Garishvili, Akio Kiyomichi, N. Kurihara, Y. Cobigo, M. G. Hur, C. Y. Chi, John Hill, H. A. Torii, Toru Sugitate, L. D. Isenhower, François Fleuret, S. N. White, K. Nakano, W. E. Sondheim, O. Dietzsch, H. Valle, Y. J. Mao, S. Kametani, P. A. Rukoyatkin, J. H. Kang, Julia Velkovska, J. S. Haggerty, A. Romana, M. Rosati, S. Gadrat, Bruno Espagnon, A. A. Vinogradov, Henrik Tydesjö, Jiangyong Jia, Y. S. Lai, Y. Goto, J. Gosset, J. P. Sullivan, S. Yokkaichi, J. M. Heuser, J. G. Boissevain, Masashi Kaneta, C. Pinkenburg, and M. Stepanov

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Range (particle radiation), Meson, 010308 nuclear & particles physics, Nuclear Theory, High Energy Physics::Phenomenology, Parton, 01 natural sciences, Nuclear physics, Baryon, 0103 physical sciences, High Energy Physics::Experiment, Production (computer science), Nuclear Experiment, 010306 general physics, Sign (mathematics), Bar (unit)
Abstract

Correlations between p and (p) over bar at transverse momenta typical of enhanced baryon production in Au + Au collisions are reported. The PHENIX experiment has measured same and opposite sign baryon pairs in Au + Au collisions at root s(NN) = 200 GeV. Correlated production of p and p with the trigger particle from the range 2.5 < p(T) < 4.0 GeV/c and the associated particle with 1.8 < p(T) < 2.5 GeV/c is observed to be nearly independent of the centrality of the collisions. Same sign pairs show no correlation at any centrality. The conditional yield of mesons triggered by baryons (and anti-baryons) and mesons in the same p(T) range rises with increasing centrality, except for the most central collisions, where baryons show a significantly smaller number of associated mesons. These data are consistent with a picture in which hard scattered partons produce correlated p and (p) over bar in the p(T) region of the baryon excess. (c) 2007 Elsevier B.V. All rights reserved.

Published
2007

33. Disentangling random thermal motion of particles and collective expansion of source from transverse momentum spectra in high energy collisions

Author

Hua-Rong Wei, Fu-Hu Liu, and Roy A. Lacey

Subjects
Nuclear and High Energy Physics, Nuclear Theory, Hadron, FOS: Physical sciences, Kinetic energy, 01 natural sciences, law.invention, High Energy Physics - Experiment, Nuclear physics, Nuclear Theory (nucl-th), High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), law, 0103 physical sciences, Invariant mass, Rapidity, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Physics, 010308 nuclear & particles physics, High Energy Physics::Phenomenology, Effective temperature, Transverse plane, High Energy Physics - Phenomenology, Quark–gluon plasma, Bose–Einstein condensate
Abstract

In the framework of a multisource thermal model, we describe experimental results of the transverse momentum spectra of final-state light flavour particles produced in gold-gold (Au-Au), copper-copper (Cu-Cu), lead-lead (Pb-Pb), proton-lead ($p$-Pb), and proton-proton ($p$-$p$) collisions at various energies, measured by the PHENIX, STAR, ALICE, and CMS Collaborations, by using the Tsallis-standard (Tsallis form of Fermi-Dirac or Bose-Einstein), Tsallis, and two- or three-component standard distributions which can be in fact regarded as different types of "thermometers" or "thermometric scales" and "speedometers". A central parameter in the three distributions is the effective temperature which contains information on the kinetic freeze-out temperature of the emitting source and reflects the effects of random thermal motion of particles as well as collective expansion of the source. To disentangle both effects, we extract the kinetic freeze-out temperature from the intercept of the effective temperature ($T$) curve as a function of particle's rest mass ($m_0$) when plotting $T$ versus $m_0$, and the mean transverse flow velocity from the slope of the mean transverse momentum ($\langle p_T \rangle$) curve as a function of mean moving mass ($\overline{m}$) when plotting $\langle p_T \rangle$ versus $\overline{m}$., 19 pages, 12 figures. Journal of Physics G, accepted

Published
2015

34. Indications for a critical point in the phase diagram for hot and dense nuclear matter

Author

Roy A. Lacey

Subjects
Physics, Nuclear and High Energy Physics, Phase transition, Condensed matter physics, Nuclear Theory, 010308 nuclear & particles physics, Critical phenomena, FOS: Physical sciences, 01 natural sciences, High Energy Physics - Experiment, Nuclear Theory (nucl-th), High Energy Physics - Experiment (hep-ex), Critical point (thermodynamics), Excited state, 0103 physical sciences, Ising model, Atomic physics, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Critical exponent, Excitation, Phase diagram
Abstract

Two-pion interferometry measurements are studied for a broad range of collision centralities in Au+Au (Root_s = 7.7 - 200 GeV) and Pb+Pb (Root_s = 2.76 TeV) collisions. They indicate non-monotonic excitation functions for the Gaussian emission source radii difference [(R_out)^2 - (R_side)^2], suggestive of reaction trajectories which spend a fair amount of time near a "soft point" in the equation of state (EOS) that coincides with the critical end point (CEP). A Finite-Size Scaling (FSS) analysis of these excitation functions, provides further validation tests for the CEP. It also indicates a second order phase transition at the CEP, and the values T^{cep} ~ 165 MeV and mu_B^{cep} ~ 95 MeV for its location in the (T, mu_B)-plane of the phase diagram. The static critical exponents (nu ~ 0.66 and gamma ~ 1.2) extracted via the same FSS analysis, place this CEP in the 3D Ising model universality class. A Dynamic Finite-Size Scaling analysis of the excitation functions, gives the estimate z ~ 0.87 for the dynamic critical exponent, suggesting that the associated critical expansion dynamics is dominated by the hydrodynamic sound mode., Comment: 4 pages, 5 figures, proceedings, QM2015

Published
2015
Full Text
View/download PDF

35. Evidence for an Emission Source of Large Space-Time Extent in Au+Au Collisions at RHIC

Author

Roy A. Lacey, P. Chung, and Collaboration PHENIX

Subjects
Source function, Nuclear physics, Physics, Nuclear and High Energy Physics, Range (particle radiation), Space time, Hadron, General Physics and Astronomy, Radius, Atomic physics, Source imaging, Nuclear Experiment, Parametrization
Abstract

The source imaging technique of Brown and Danielewicz has been used to extract two-pion emission source functions over a broad range of k T and centralities in Au+Au collisions at $$\sqrt s = 200$$ GeV. The source functions reflect the combined contributions of a short-range Gaussian-like component and a long-range exponential-like component. A parametrization of the source function gives a RMS radius for the long-range source which is approximately three times that for the short-range source. The centrality dependence of the extracted source parameters for the short- and long-range sources indicate similar patterns.

Published
2006

36. Indications for a critical end point in the phase diagram for hot and dense nuclear matter

Author

Roy A. Lacey

Subjects
Physics, Phase transition, High Energy Physics::Phenomenology, General Physics and Astronomy, Mechanics, Nuclear matter, Nuclear physics, Tricritical point, Critical point (thermodynamics), Ising model, Impact parameter, Nuclear Experiment, Scaling, Phase diagram
Abstract

Excitation functions for the Gaussian emission source radii difference (R_{out}^{2}-R_{side}^{2}) obtained from two-pion interferometry measurements in Au+Au (sqrt[s_{NN}]=7.7-200 GeV) and Pb+Pb (sqrt[s_{NN}]=2.76 TeV) collisions are studied for a broad range of collision centralities. The observed nonmonotonic excitation functions validate the finite-size scaling patterns expected for the deconfinement phase transition and the critical end point (CEP), in the temperature versus baryon chemical potential (T,μ_{B}) plane of the nuclear matter phase diagram. A finite-size scaling (FSS) analysis of these data suggests a second order phase transition with the estimates T^{cep}∼165 MeV and μ_{B}^{cep}∼95 MeV for the location of the critical end point. The critical exponents (ν≈0.66 and γ≈1.2) extracted via the same FSS analysis place this CEP in the 3D Ising model universality class.

Published
2014

37. Extraction of Source Images in Au+Au and d+Au collisions at RHIC

Author

James Alexander, Wolf G. Holzmann, P. Chung, M. Issah, A. Taranenko, and Roy A. Lacey

Subjects
Physics, Nuclear and High Energy Physics, symbols.namesake, Gaussian, symbols, Imaging technique, Radius, Atomic physics, Nuclear Experiment
Abstract

The PHENIX Collaboration has performed a systematic study of two-pion correlations in Au+Au and d+Au collisions at RHIC ( s = 200 AGeV ) . The correlations have been analyzed using the Imaging technique of Brown and Danielewicz to extract the two-pion source functions as a function of m T and centrality. The source images are characterised by a short-range Gaussian-like core and a long-range exponential-like tail with a characteristic radius about 3 times that of the Gaussian core. The m T and centrality dependence of the source parameters indicate that the two structures are intricately related.

Published
2005

38. Ξ production at AGS energies

Author

James Alexander, Roy A. Lacey, Che Ming Ko, Subrata Pal, and P. Chung

Subjects
Physics, Nuclear and High Energy Physics, Nuclear Theory, 010308 nuclear & particles physics, Abundance (chemistry), Hyperon, 7. Clean energy, 01 natural sciences, Nuclear physics, Cross section (physics), Cascade, Yield (chemistry), 0103 physical sciences, Atomic physics, Chemical equilibrium, Nuclear Experiment, 010306 general physics, Beam energy
Abstract

A relativistic transport model is used to study Xi- production in 2-11A GeV Au+Au collisions. Introducing the strangeness-exchange reactions between antikaons and hyperons as the sources for Xi-, we find that the cascade yield in these collisions is in reasonable agreement with the data. Although the Xi- abundance does not reach chemical equilibrium unless the cross section for strangeness-exchange reactions is enhanced by six times, it exhibits the strongest enhancement with increasing centrality of collision and with increasing beam energy., Comment: Title changed, Modified version, 5 pages, RevTex

Published
2004

39. Neutral strange particle dynamics in Au $plus$ Au collisions at AGS energies

Author

P Chung for the E895 Collaboration, J M Alexander, N N Ajitanand, M Anderson, D Best, F P Brady, T Case, W Caskey, D Cebra, J L Chance, P Chung, B Cole, K Crowe, A C Das, J E Draper, M L Gilkes, S Gushue, M Heffner, A S Hirsch, E L Hjort, L Huo, M Justice, M Kaplan, D Keane, J C Kintner, J Klay, D Krofcheck, Roy A Lacey, J Lauret, M A Lisa, H Liu, Y M Liu, R McGrath, Z Milosevich, G Odyniec, D L Olson, S Panitkin, C Pinkenburg, N T Porile, G Rai, H G Ritter, J L Romero, R Scharenberg, L Schroeder, B Srivastava, N T B Stone, T J M Symons, J Whitfield, T Wienold, R Witt, L Wood, and W N Zhang

Subjects
Physics, Nuclear and High Energy Physics, Strange quark, Space time, Gaussian, Dynamics (mechanics), Magnitude (mathematics), Scattering length, Radius, Nuclear physics, symbols.namesake, Pion, symbols, High Energy Physics::Experiment, Atomic physics, Nuclear Experiment
Abstract

The E895 Collaboration has investigated a number of mixed-particle correlations involving neutral strange particles (K0s and Λ) in 2, 4, 6 and 8 A GeV Au + Au collisions at the AGS. The first measurements for pΛ correlations indicate a correlation magnitude of about 50% with a 26 MeV width. Detailed comparisons between data and theory suggest an emitting source with an effective Gaussian radius close to 4.5 fm. This radius is much larger than the value of 2.8 fm predicted by the relativistic transport code ART. Pairs of pK0, π−Λ and π−K0 are found to display essentially zero correlation at 6 A GeV. The latter observations are not unexpected considering that the proton–K0 interaction has a very small scattering length and there are no very well known interactions between pions and Λs or K0s.

Published
2002

40. Elliptic flow measurements with the PHENIX detector

Author

Roy A. Lacey

Subjects
Physics, Nuclear and High Energy Physics, Plane (geometry), Elliptic flow, Hadron, FOS: Physical sciences, Nuclear physics, Azimuth, Transverse plane, Particle, Sensitivity (control systems), Nuclear Experiment (nucl-ex), PHENIX detector, Nuclear Experiment
Abstract

Two particle azimuthal correlation functions are presented for charged hadrons produced in Au+Au collisions at RHIC ($\sqrt{s_{_{NN}}}=130$ GeV). The measurements allow for the determination of elliptic flow without event-by-event estimation of the reaction plane. The measured correlation functions indicate elliptic flow values ($v_2$) which show significant sensitivity to both the collision centrality and the transverse momenta of emitted hadrons., Comment: Contribution to Quark Matter 2001, Long Island, New York, January 15-20, 2001

Published
2002

41. Particles: A New International Open Access Journal for Nuclear and Particle Physics

Author

Roy A. Lacey

Subjects
Physics, Set (abstract data type), Particle physics, Span (engineering), Computer Science::Digital Libraries, Original research, Open access journal
Abstract

Particles, a new online, open access journal, has been launched to facilitate the publication of original research papers, review articles, and communications of new results and progress in a broad set of subfields which span nuclear and particle physics, experimental/theoretical high-energy physics and astrophysics.[...]

Published
2017

42. Beam energy dependence of the expansion dynamics in relativistic heavy ion collisions: Indications for the critical end point?

Author

Roy A. Lacey

Subjects
Physics, Quantum chromodynamics, Nuclear reaction, Nuclear and High Energy Physics, Phase transition, Critical phenomena, FOS: Physical sciences, Nuclear matter, Nuclear physics, Reaction dynamics, Nuclear Experiment (nucl-ex), Atomic physics, Nuclear Experiment, Beam (structure), Phase diagram
Abstract

The flow harmonic $v_{n}$ and the emission source radii $R_{\text{out}}$, $R_{\text{side}}$ and $R_{\text{long}}$ are studied for a broad range of centrality selections and beam collision energies in Au+Au ($\sqrt{s_{NN}}= 7.7 - 200$ GeV) and Pb+Pb ($\sqrt{s_{NN}}= 2.76$ TeV) collisions at RHIC and the LHC respectively. They validate the acoustic scaling patterns expected for hydrodynamic-like expansion over the entire range of beam energies studied. The combined data sets allow estimates for the \sqsn\ dependence of the mean expansion speed $\left$, emission duration $\left$ and the viscous coefficients $\left$ that encode the magnitude of the specific shear viscosity $\left$. The estimates indicate initial-state model independent values of $\left$ which are larger for the plasma produced at 2.76 TeV (LHC) compared to that produced at 200 GeV (RHIC) ($\left_{\text{LHC}}=2.2\pm 0.2$ and $\left_{\text{RHIC}}=1.3\pm 0.2$). They also show a non-monotonic \sqsn\ dependence for $\left$, $\left$ and $\left$, with minima for $\left$ and $\left$, and a complimentary maximum for $\left$. These dependencies signal a significant change in reaction dynamics in a narrow span of $\sqrt{s_{NN}}$, which may be linked to reaction trajectories close to the critical end point (CEP) in the phase diagram for nuclear matter., Comment: 4 pages, 4 figures, proceedings for International Conference on Quark Matter (QM2014)

Published
2014

44. Centrality Dependence of Charged Particle Multiplicity in Au-Au Collisions atsNN=130GeV

Author

I. Ravinovich, N. N. Ajitanand, M. Rosati, F. Plasil, L. Paffrath, M. Velkovsky, S. S. Ryu, Z. Sun, A. A. Vinogradov, Henrik Tydesjö, A. Durum, Hiroyuki Sako, T. Ichihara, D. S. Brown, F. K. Wohn, T. K. Ghosh, Jiangyong Jia, Y. Goto, Sean A. Kelly, A. G. Hansen, A. A. Tsvetkov, J. P. Sullivan, S. F. Pate, B. Khachaturov, D. Kochetkov, Y. H. Shin, Hideki Hamagaki, I. D. Ojha, M. Suzuki, J. Simon-Gillo, T. Peitzmann, G. David, Saskia Mioduszewski, T. L. Thomas, S. Esumi, R. E. Mischke, Tai Sakuma, X. He, V.A. Onuchin, A. Glenn, B. V. Dinesh, L. Aphecetche, V. Papavassiliou, P. L. McGaughey, S. H. Aronson, S. K. Tuli, H. Wang, Norio Saito, W. A. Zajc, P. Pitukhin, Ryugo S. Hayano, S. Markacs, Y. Riabov, Kenta Shigaki, S. Belikov, Yoshio Arai, V. Cianciolo, Yves Roland Schutz, C. Pinkenburg, P. D. Barnes, I. Shein, Joakim Nystrand, Shiv K. Gupta, P. J. Kroon, J. M. Burward-Hoy, V. S. Pantuev, Ju Hwan Kang, Y. Nakada, J. M. Heuser, J. Chiba, Shunji Nishimura, A. Franz, L. Kochenda, A. S. Nyanin, Sergey Fokin, Senta Greene, B. R. Schlei, E. M. Takagui, B. A. Cole, T. C. Sangster, S. N. White, S. Butsyk, G. C. Mishra, R. S. Towell, E. J. Desmond, C. P. Singh, Akira Masaike, S. S. Adler, G. S. Kyle, D. J. Lim, James Alexander, Kwang Souk Sim, J. H. Thomas, Takao Sakaguchi, Junji Tojo, K. Kurita, A. Ster, A. Hoover, I. Tserruya, C. L. Woody, Vladimir Samsonov, I. Otterlund, K. El Chenawi, R. Averbeck, Byung-Sik Hong, C. Klein-Boesing, I. G. Sibiriak, E. O'Brien, M. Hibino, Yu. Efremenko, A. Bazilevsky, M. J. Bennett, S. Garpman, O. Dietzsch, Minghui Liu, J.R. Mahon, M. Sivertz, A. P.T. Palounek, A. D. Frawley, N. Hayashi, V. Singh, J. S. Haggerty, S. Y. Kim, A. A. Rose, Alexandre Lebedev, D. S. Ho, R. A. Soltz, Dipanwita Dutta, Kenneth Francis Read, D. M. Lee, H. A. Gustafsson, F. Messer, D. E. Fields, Hiroaki Ohnishi, T. Ushiroda, W. W. Kinnison, M. J. Leitch, A. L. Godoi, S. T. Belyaev, An.A. Vorobyov, A. Denisov, S. Sawada, T. E. Miller, D. Koehler, Julia Velkovska, C. Y. Chi, B. V. Jacak, H. En'yo, L. Nikkinen, M. Grosse Perdekamp, H. Tsuruoka, T. A. Carey, E. P. Hartouni, Y. I. Makdisi, H. Hara, J. L. Nagle, S. C. Johnson, Y. J. Mao, S. S. Kapoor, T. Kohama, K. Ebisu, S. P. Stoll, M. S. Chung, H. Torii, X. Liu, S. Yokkaichi, L. L. Chavez, M. J. Kweon, H. Buesching, Y. J. Kwon, Viktor Riabov, I. E. Yushmanov, Alexei Khanzadeev, G. R. Young, K. Adcox, Susumu Sato, M. Muniruzzaman, M. Messer, A. Kozlov, C. Velissaris, R. Seto, Zhedong Zhang, Xingguo Li, M. Pollack, E. Vznuzdaev, V. Baublis, V. Bumazhnov, Hirohiko Sato, N. Bruner, M. J. Tannenbaum, E. Stenlund, T. C. Awes, P. Chand, Jun Kikuchi, S. P. Sorensen, Takehiko Matsumoto, Atsushi Taketani, E. Taniguchi, David Olle Rickard Silvermyr, K. N. Barish, R. Santo, Martin Purschke, P. Steinberg, D. Bucher, Peter M. Nilsson, T. Shiina, F. G. Bellaiche, J. G. Lajoie, M. Ono, A. Kiyomichi, P. Chung, W. C. Chang, S. Kametani, Y. Watanabe, Z. Fraenkel, S. Nagamiya, Roy A. Lacey, K. Pope, K. S. Joo, Wei Xie, Dong Jo Kim, Yasushi Nagasaka, N. Starinsky, B. M. Johnson, A. Soldatov, M. L. Brooks, A. Deshpande, Alexander Milov, C. Witzig, D. P. Morrison, K. Imai, V. E. Semenov, M. Sugioka, T. Christ, Jason Newby, M. Chiu, Ajit Kumar Mohanty, T. A. Shibata, J. Murata, W. Guryn, B. K. Nandi, Y. Akiba, S. K. Mark, David D'Enterria, R. P. Pisani, Nikolay Tyurin, German Martinez, Vladislav Manko, M. D. Marx, R. K. Choudhury, H. Delagrange, T. Chujo, K. Yagi, S. Zhou, Markus Merschmeyer, S. Bathe, Kensuke Homma, E. Melnikov, S. Chernichenko, B. Bassalleck, F. Mühlbacher, L. Ewell, J. Lauret, Aya Sakaguchi, Agneta Oskarsson, Y. Berdnikov, Lennart Osterman, Kazuhiro Tanaka, Klaus Johannes Reygers, V. Kochetkov, M. A. Volkov, J. Chang, C. A. Ogilvie, Yongsun Kim, P. W. Stankus, T. K. Hemmick, J. T. Mitchell, Yasuo Miake, H. W. Van Hecke, Zhongfan Liu, W. Y. Jang, G. Bunce, T. Ferdousi, H. J. Kim, Juergen Thomas, M. Ishihara, Athanasios Petridis, Y. Tanaka, T. K. Shea, F. Matathias, J. Barrette, M. Kann, Charles Maguire, S. Klinksiek, Y. Sumi, Wei Tian, A. Drees, Josh Moss, M. Tamai, E. Kistenev, Mikhail Ippolitov, S. Botelho, S. Y. Fung, John Hill, K. Oyama, Toru Sugitate, and Z. Li

Subjects
Physics, Nuclear physics, Particle physics, General Physics and Astronomy, High Energy Physics::Experiment, Multiplicity (mathematics), PHENIX detector, Nuclear Experiment, Particle density, Nucleon, Centrality, Charged particle, Multiplicity distribution
Abstract

We present results for the charged-particle multiplicity distribution at midrapidity in Au-Au collisions at square root of [s(NN)] = 130 GeV measured with the PHENIX detector at RHIC. For the 5% most central collisions we find dN(ch)/d eta(vertical line eta = 0) = 622+/-1(stat)+/-41(syst). The results, analyzed as a function of centrality, show a steady rise of the particle density per participating nucleon with centrality.

Published
2001

45. Directed Flow ofΛHyperons in(2–6)AGeVAu+AuCollisions

Author

M. A. Lisa, S. Y. Panitkin, N. T. B. Stone, H. G. Ritter, L. S. Schroeder, D. Best, David Krofcheck, E. Hjort, T. Wienold, T. Case, D. Keane, P. Chung, N. N. Ajitanand, G. Rai, J. L. Chance, Morton Kaplan, D. Cebra, F. P. Brady, G. Odyniec, S. Gushue, J. Whitfield, Y. M. Liu, Z. Milosevich, R. Witt, M. L. Gilkes, B. K. Srivastava, T. J. M. Symons, J. L. Romero, L. Wood, Brian Cole, Matthew J. Anderson, N. T. Porile, R. P. Scharenberg, J. Lauret, R. L. McGrath, J. M. Alexander, A. C. Das, H. Liu, J. L. Klay, Roy A. Lacey, M. Heffner, A. S. Hirsch, J. E. Draper, W. N. Zhang, M. Justice, Kenneth M. Crowe, D. L. Olson, W. Caskey, J. C. Kintner, Lei Huo, and C. Pinkenburg

Subjects
Nuclear reaction, Physics, Nuclear Theory, Hadron, Hyperon, General Physics and Astronomy, Elementary particle, Lambda baryon, Lambda, Baryon, Nuclear physics, Atomic physics, Nuclear Experiment, Nucleon
Abstract

Directed flow measurements for {Lambda} hyperons are presented and compared to those for protons produced in the same Au+Au collisions (2A, 4A, and 6AGeV; b

Published
2001

46. Λ flow and Λ-P correlation in Au + Au collisions at AGS energies

Author

C. Law, A. S. Hirsch, J. Whitfield, F. P. Brady, G. Odyniec, N. N. Ajitanand, J. E. Draper, K.M. Crowe, Lei Huo, W. N. Zhang, J. Lauret, N T B Stone, James Alexander, M. L. Gilkes, L. Wood, H. G. Ritter, Brian Cole, Matthew J. Anderson, J L Chance, M. Heffner, R. P. Scharenberg, A. C. Das, Y. M. Liu, H. Liu, Morton Kaplan, S. Y. Panitkin, Roy A. Lacey, C. Pinkenburg, S Gushue, T. J. M. Symons, E. L. Hjort, M. A. Lisa, M. Justice, D. Cebra, D. L. Olson, W. Caskey, Z. Milosevich, J. C. Kintner, R. Witt, L. S. Schroeder, B. K. Srivastava, D. Keane, P. Chung, G. Rai, T. Case, J. Klay, D. Best, J. L. Romero, David Krofcheck, N. T. Porile, and R. L. McGrath

Subjects
Quark, Physics, Nuclear and High Energy Physics, Scattering, Nuclear Theory, Hyperon, Magnitude (mathematics), Nuclear physics, Flow ratio, Transverse plane, Flow (mathematics), Atomic physics, Nuclear Experiment, Beam (structure)
Abstract

Transverse and radial flow measurements are presented for Λ hyperons along with Λ-P correlations from Au + Au collisions at AGS energies. The flow measurements are compared with those of co-produced protons. The measurements indicate that Λ hyperons flow consistently in the same direction as protons but with a smaller magnitude for all beam energies. Comparisons with RQMD calculations show that the experimentally determined Λ sideward flow is consistently larger compared with the calculated value obtained from scattering processes only. The experimental transverse flow ratio Λ/P is consistent with predictions ( 2/3) of the quark counting rule at 2 A GeV but is found to decrease with increasing beam energy. These observations may be related to the detailed features of the Λ-nucleon potential for the nuclear densities produced. At 6 A GeV, Λp correlation functions are observed to be essentially flat (within statistical uncertainty), indicating little or no correlation between Λs and co-produced protons. This suggests that Λs may have a spacetime emission pattern which is different from that for protons. Further evidence from radial flow measurements also indicates that 6 A GeV Λ hyperons (at mid-rapidity) do not share the same emitting source characteristics as co-produced protons.

Published
2001

47. Antiflow ofKs0Mesons in6AGeVAu+AuCollisions

Author

James Alexander, E. Hjort, A. S. Hirsch, T. Case, H. G. Ritter, F. P. Brady, G. Odyniec, J. L. Romero, N. T. Porile, M. A. Lisa, Kenneth M. Crowe, H. Liu, N. T. B. Stone, Brian Cole, Matthew J. Anderson, L. S. Schroeder, R. L. McGrath, R. P. Scharenberg, R. Witt, A. C. Das, W. N. Zhang, N. N. Ajitanand, B. K. Srivastava, J. Lauret, J. L. Klay, Roy A. Lacey, M. Justice, M. Heffner, Lei Huo, S. Gushue, M. L. Gilkes, J. Whitfield, T. Wienold, S. Y. Panitkin, C. Pinkenburg, Morton Kaplan, L. Wood, J. L. Chance, D. Cebra, J. E. Draper, Z. Milosevich, D. L. Olson, W. Caskey, Y. M. Liu, T. J. M. Symons, G. Rai, D. Keane, P. Chung, D. Best, David Krofcheck, and J. C. Kintner

Subjects
Nuclear reaction, Physics, Range (particle radiation), Meson, 010308 nuclear & particles physics, Hadron, General Physics and Astronomy, Elementary particle, Nuclear matter, 01 natural sciences, Nuclear physics, 0103 physical sciences, Impact parameter, 010306 general physics, Boson
Abstract

We have measured the sideward flow of neutral strange (K{sup 0}{sub s} ) mesons in 6A GeV Au +Au collisions. A prominent antiflow signal is observed for an impact parameter range (b(less-or-similar sign)7 fm ) which spans central and midcentral events. Since the K{sup 0}{sub s} scattering cross section is relatively small in nuclear matter, this observation suggests that the in-medium kaon vector potential plays an important role in high density nuclear matter. (c) 2000 The American Physical Society.

Published
2000

48. Bombarding Energy Dependence ofπ−Interferometry at the Brookhaven AGS

Author

G. Odyniec, S. Gushue, E. Hjort, D. Best, T. Case, W. N. Zhang, T. J. M. Symons, J. L. Romero, H. G. Ritter, R. P. Scharenberg, David Krofcheck, Y. M. Liu, J. L. Chance, Kenneth M. Crowe, M. L. Gilkes, D. Cebra, A. C. Das, H. Liu, Brian Cole, Matthew J. Anderson, J. L. Klay, Roy A. Lacey, F. P. Brady, J. E. Draper, M. Heffner, J. Whitfield, D. Keane, P. Chung, A. S. Hirsch, J. Lauret, N. N. Ajitanand, M. A. Lisa, J. C. Kintner, G. Rai, S. Y. Panitkin, Russell Wells, J. M. Alexander, R. Witt, L. Wood, B. K. Srivastava, D. L. Olson, W. Caskey, N. T. B. Stone, M. Justice, N. T. Porile, R. L. McGrath, L. S. Schroeder, Lei Huo, C. Pinkenburg, Z. Milosevich, T. Wienold, and Morton Kaplan

Subjects
Physics, Nuclear physics, Excitation function, Mean field theory, Reaction dynamics, General Physics and Astronomy, Alternating Gradient Synchrotron, Sensitivity (control systems), Atomic physics, Nuclear Experiment, Nuclear matter, Intensity (heat transfer), Energy (signal processing)
Abstract

We present the first excitation function of ${\ensuremath{\pi}}^{\ensuremath{-}}$ intensity interferometry at Alternating Gradient Synchrotron (AGS) energies (2--8 A GeV). The sensitivity of the multidimensional correlation functions to the geometry and dynamics of the pion-emitting system provides a stringent test of transport models of heavy ion collisions. Detailed comparisons with a realistic transport model, both with and without an explicit nuclear mean field, suggest that the beam energy evolution in the reaction dynamics is different in the model than in the data. A significantly increased ${\ensuremath{\pi}}^{\ensuremath{-}}$ emission time scale, which has been suggested as a signal of the onset of the transition to quark-gluon plasma, is not observed.

Published
2000

49. Balance of Mass, Momentum, and Energy in Splintering Central Collisions forA40rup to 115 MeV/Nucleon

Author

M. Stern, C. J. Gelderloos, D. Guinet, Eugene Gualtieri, G. D. Westfall, N. N. Ajitanand, Rulin Sun, R. Pak, J. Lauret, A. Elmaani, Ludwik Kowalski, N. T. B. Stone, M. A. Barton, J. A. Jaasma, Vander Molen Am, James Alexander, K. L. Drake, E. Norbeck, S. D. Sundbeck, J. Yee, L. B. Yang, S. Hannuschke, Paul DeYoung, Graham F. Peaslee, E. Colin, and Roy A. Lacey

Subjects
Physics, 010308 nuclear & particles physics, Nuclear Theory, Isotropy, General Physics and Astronomy, Energy–momentum relation, 01 natural sciences, 7. Clean energy, Charged particle, Nuclear physics, Momentum, Angular distribution, 0103 physical sciences, Deposition (phase transition), Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon
Abstract

For central collisions of 17-115 A MeV {sup 40}Ar+Cu , Ag, Au, an overall balance is determined for the average mass, energy, and longitudinal momentum. Light charged particles and fragments are separated into forward-focused and isotropic components in the frame of the heaviest fragment. Energy removal by the isotropic component reaches 1-2 GeV. For such high deposition energies, statistical multifragmentation models predict much more extensive nuclear disassembly than is observed. (c) 1999 The American Physical Society.

Published
2000

50. The pixel readout system for the PHENIX pad chambers

Author

J. Barrette, I. Tserruya, A. Rose, Melissa C. Smith, Paul Nilsson, S. K. Mark, Alexander Milov, Z. Fraenkel, I. Otterlund, Agneta Oskarsson, Roy A. Lacey, H. A. Gustafsson, E. Stenlund, W.L. Bryan, E. O'Brien, V. Greene, C. Pinkenburg, I. Ravinovich, J. Lauret, T. Svensson, G. R. Young, David Olle Rickard Silvermyr, Lennart Österman, L. Nikkinen, U. Jagadish, M. Sivertz, Wei Xie, O. Teodorescu, and S. Garpman

Subjects
Physics, Nuclear and High Energy Physics, Pixel, Spectrometer, Physics::Instrumentation and Detectors, business.industry, Particle detector, Cathode, law.invention, Nuclear physics, Optics, law, Measuring instrument, Electronics, business, Relativistic Heavy Ion Collider, Electronic circuit
Abstract

A new concept for two-dimensional position readout of wire chambers is described. The basic idea is to use a cathode segmented into small pixels that are read out in specific groups (pads). The electronics is mounted on the outer face of the chamber with a chip-on-board technique, pushing the material thickness to a minimum. The system described here, containing 210 000 readout channels, will be used to read out the pad chambers in the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC).

Published
1999

Catalog

Books, media, physical & digital resources
See catalog results