\begin{document}$ v_1 $\end{document}) of inclusive light hadrons is independent of the collision system size at a given centrality [1]. However, recent STAR measurements indicate a system-size dependence in the \begin{document}$ v_1(y) $\end{document}-slope (\begin{document}$ {\rm d}v_{1}/{\rm d}y $\end{document}) of protons, antiprotons, and their differences (\begin{document}$ \Delta {\rm d}v_{1}/{\rm d}y $\end{document}) at a given centrality, suggesting a potential influence of baryon production and transport mechanisms [2]. In this study, we analyzed pseudorapidity (\begin{document}$ {\rm d}N/{\rm d}y $\end{document}) distributions and directed flow (\begin{document}$ v_1 $\end{document} and \begin{document}$ {\rm d}v_{1}/{\rm d}y $\end{document}) for pions, kaons, and protons in Au+Au and Cu+Cu collisions at \begin{document}$ \sqrt{s_{NN}} = 19.6 $\end{document} GeV using A Multi-Phase Transport (AMPT) model. Specifically, we investigated the influence of string junction parameters in the AMPT model via the PYTHIA/JETSET routines, focusing on the popcorn mechanism and string-splitting parameters, on \begin{document}$ {\rm d}N/{\rm d}y $\end{document}, \begin{document}$ {\rm d}v_{1}/{\rm d}y $\end{document}, and their charge-dependent splittings (\begin{document}$ \Delta {\rm d}N/{\rm d}y $\end{document} and \begin{document}$ \Delta {\rm d}v_{1}/{\rm d}y $\end{document}). We observed that string junction parameters can affect \begin{document}$ {\rm d}N/{\rm d}y $\end{document}, \begin{document}$ {\rm d}v_{1}/{\rm d}y $\end{document}, \begin{document}$ \Delta {\rm d}N/{\rm d}y $\end{document}, and \begin{document}$ \Delta {\rm d}v_{1}/{\rm d}y $\end{document} for π, K, and p, and influence their system-size dependence. The effect is most prominent on the \begin{document}$ v_1 $\end{document} value of protons and non-trivial for kaons; the \begin{document}$ v_1 $\end{document} value of pions remains largely unchanged. These findings provide insights into the interplay among particle production mechanisms, baryon transport, and directed flow in heavy-ion collisions."> Impact of particle production mechanisms on pseudorapidity distribution and directed flow in Au+Au and Cu+Cu collisions at <inline-formula><tex-math id="M1">\begin{document}${ \sqrt{{\boldsymbol s}_{\boldsymbol{ NN}}}}$\end{document}</tex-math><alternatives><graphic specific-use="online" xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="//www.macurncorp.com/hepnp/article/app/id/cf76bc84-6cc4-487b-b9b7-e2d0c6d05e98/CPC-2025-0039_M1.jpg"/><graphic specific-use="print" xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="//www.macurncorp.com/hepnp/article/app/id/cf76bc84-6cc4-487b-b9b7-e2d0c6d05e98/CPC-2025-0039_M1.png"/></alternatives></inline-formula> = 19.6 GeV using AMPT model -
  • [1]

    B. I. Abelevet al. (STAR), Phys. Rev. Lett.101, 252301 (2008), arXiv: 0807.1518[nucl-ex]

  • [2]

    M. F. Taseeret al. (for STAR Collaboration), Contribution to SQM 2024 (2024), https://indico.in2p3.fr/event/29792/ contributions/137162/.

  • [3]

    J. Adamset al. (STAR), Nucl. Phys. A757, 102 (2005), arXiv: nucl-ex/0501009

  • [4]

    K. Adcoxet al. (PHENIX), Nucl. Phys. A757, 184 (2005), arXiv: nucl-ex/0410003

  • [5]

    I. Arseneet al. (BRAHMS), Nucl. Phys. A757, 1 (2005), arXiv: nucl-ex/0410020

  • [6]

    J. W. Harris and B. Muller, Ann. Rev. Nucl. Part. Sci.46, 71 (1996), arXiv: hep-ph/9602235

  • [7]

    B. Muller, J. Schukraft, and B. Wyslouch, Ann. Rev. Nucl. Part. Sci.62, 361 (2012), arXiv: 1202.3233[hep-ex]

  • [8]

    P. Braun-Munzinger and J. Stachel, Nature448, 302 (2007)

  • [9]

    J. Y. Ollitrault, Phys. Rev. D46, 229 (1992)

  • [10]

    A. M. Poskanzer and S. A. Voloshin, Phys. Rev. C58, 1671 (1998), arXiv: nucl-ex/9805001

  • [11]

    S. Voloshin and Y. Zhang, Z. Phys. C70, 665 (1996), arXiv: hep-ph/9407282

  • [12]

    J. Brachmann, S. Soff, A. Dumitruet al., Phys. Rev. C61, 024909 (2000), arXiv: nucl-th/9908010

  • [13]

    P. Chunget al. (E895), Phys. Rev. Lett.85, 940 (2000), arXiv: nucl-ex/0101003

  • [14]

    P. Chunget al., Phys. Rev. Lett.86, 2533 (2001), arXiv: nucl-ex/0101002

  • [15]

    C. Altet al. (NA49), Phys. Rev. C68, 034903 (2003), arXiv: nucl-ex/0303001

  • [16]

    J. Adamset al. (STAR), Phys. Rev. Lett.92, 062301 (2004) [Erratum: Phys. Rev. Lett.127, 069901 (2021)]., arXiv: nucl-ex/0310029

  • [17]

    B. B. Backet al. (PHOBOS), Phys. Rev. Lett.97, 012301 (2006), arXiv: nucl-ex/0511045

  • [18]

    B. Abelevet al. (ALICE), Phys. Rev. Lett.111, 232302 (2013), arXiv: 1306.4145[nucl-ex]

  • [19]

    H. Stoecker, Nucl. Phys. A750, 121 (2005), arXiv: nucl-th/0406018

  • [20]

    Y. Nara, H. Niemi, A. Ohnishiet al., Phys. Rev. C94, 034906 (2016), arXiv: 1601.07692[hep-ph]

  • [21]

    V. P. Konchakovski, W. Cassing, Y. B. Ivanovet al., Phys. Rev. C90, 014903 (2014), arXiv: 1404.2765[nucl-th]

  • [22]

    L. Adamczyket al. (STAR), Phys. Rev. Lett.112, 162301 (2014), arXiv: 1401.3043[nucl-ex]

  • [23]

    L. Adamczyket al. (STAR), Phys. Rev. Lett.120, 062301 (2018), arXiv: 1708.07132[hep-ex]

  • [24]

    S. Singha, P. Shanmuganathan, and D. Keane, Adv. High Energy Phys.2016, 2836989 (2016), arXiv: 1610.00646 [nucl-ex]

  • [25]

    D. E. Kharzeev, L. D. McLerran, and H. J. Warringa, Nucl. Phys. A803, 227 (2008), arXiv: 0711.0950[hep-ph]

  • [26]

    L. McLerran and V. Skokov, Nucl. Phys. A929, 184 (2014), arXiv: 1305.0774[hep-ph]

  • [27]

    U. Gursoy, D. Kharzeev, and K. Rajagopal, Phys. Rev. C89, 054905 (2014), arXiv: 1401.3805[hep-ph]

  • [28]

    U. Gürsoy, D. Kharzeev, E. Marcuset al., Phys. Rev. C98, 055201 (2018), arXiv: 1806.05288[hep-ph]

  • [29]

    M. I. Abdulhamidet al. (STAR), Phys. Rev. X14, 011028 (2024), arXiv: 2304.03430[nucl-ex]

  • [30]

    STAR (STAR), (2023), arXiv: 2304.02831[nucl-ex]

  • [31]

    T. Parida and S. Chatterjee, (2023), arXiv: 2305.08806 [nucl-th]

  • [32]

    T. Parida and S. Chatterjee, (2023), arXiv: 2305.10371 [nucl-th]

  • [33]

    T. Parida, S. Chatterjee, and S. Singha, (2025), arXiv: 2503.04660[nucl-th]

  • [34]

    M. Isse, A. Ohnishi, N. Otukaet al., Phys. Rev. C72, 064908 (2005), arXiv: nucl-th/0502058

  • [35]

    Y. Nara and A. Ohnishi, Phys. Rev. C105, 014911 (2022), arXiv: 2109.07594[nucl-th]

  • [36]

    Y. Nara, T. Maruyama, and H. Stoecker, Phys. Rev. C102, 024913 (2020), arXiv: 2004.05550[nucl-th]

  • [37]

    Z. W. Lin, C. M. Ko, B. A. Liet al., Phys. Rev. C72, 064901 (2005), arXiv: nucl-th/0411110

  • [38]

    X. N. Wang and M. Gyulassy, Phys. Rev. D44, 3501 (1991)

  • [39]

    B. Zhang, Comput. Phys. Commun.109, 193 (1998), arXiv: nucl-th/9709009

  • [40]

    B. Andersson, G. Gustafson, and B. Soderberg, Z. Phys. C20, 317 (1983)

  • [41]

    B. Andersson, G. Gustafson, G. Ingelmanet al., Phys. Rept.97, 31 (1983)

  • [42]

    T. Sjostrand, Comput. Phys. Commun.82, 74 (1994)

  • [43]

    B. A. Li and C. M. Ko, Phys. Rev. C52, 2037 (1995), arXiv: nucl-th/9505016

  • [44]

    Z. w. Lin, S. Pal, C. M. Koet al., Phys. Rev. C64, 011902 (2001), arXiv: nucl-th/0011059

  • [45]

    L. Adamczyket al. (STAR), Phys. Rev. C96, 044904 (2017), arXiv: 1701.07065[nucl-ex]

Baidu
map