Anisotropic Flow in Fixed-Target <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:mmultiscripts> <mml:mrow> <mml:mi>Pb</mml:mi> </mml:mrow> <mml:mprescripts/> <mml:none/> <mml:mrow> <mml:mn>208</mml:mn> </mml:mrow> </mml:mmultiscripts> </mml:mrow> <mml:mo>+</mml:mo> <mml:mrow> <mml:mmultiscripts> <mml:mrow> <mml:mi>Ne</mml:mi> </mml:mrow> <mml:mprescripts/> <mml:none/> <mml:mrow> <mml:mn>20</mml:mn> </mml:mrow> </mml:mmultiscripts> </mml:mrow> </mml:math> Collisions as a Probe of Quark-Gluon Plasma
Giuliano Giacalone, W. Zhao, B. Bally, Shihang Shen, T. Duguet, J.-P. Ebran, Serdar Elhatisari, Mikaël Frosini, Timo A. Lähde, Dean Lee, Bing-Nan Lu, Y. Z., Ulf-G. Meißner, Govert Nijs, Jacquelyn Noronha-Hostler, Christopher Plumberg, T. Rodrı́guez, Robert Roth, Wilke van der Schee, Björn Schenke, Chun Shen, V. Somà
Abstract
The System for Measuring Overlap with Gas (SMOG2) at the LHCb detector enables the study of fixed-target ion-ion collisions at relativistic energies (sqrt[s_{NN}]∼100 GeV in the center of mass). With input from ab initio calculations of the structure of ^{16}O and ^{20}Ne, we compute 3+1D hydrodynamic predictions for the anisotropic flow of Pb+Ne and Pb+O collisions to be tested with upcoming LHCb data. This will allow the detailed study of quark-gluon plasma formation as well as experimental tests of the predicted nuclear shapes. Elliptic flow (v_{2}) in Pb+Ne collisions is greatly enhanced compared to the Pb+O baseline due to the shape of ^{20}Ne, which is deformed in a bowling-pin geometry. Owing to the large ^{208}Pb radius, this effect is seen in a broad centrality range, a unique feature of this collision configuration. Larger elliptic flow further enhances the quadrangular flow (v_{4}) of Pb+Ne collisions via nonlinear coupling, and impacts the sign of the kurtosis of the elliptic flow vector distribution (c_{2}{4}). Exploiting the shape of ^{20}Ne proves thus an ideal method to investigate the formation of quark-gluon plasma in fixed-target experiments at LHCb, and demonstrates the power of System for Measuring Overlap with Gas as a tool to image nuclear ground states.