Barbalinardo et al. Reply:

Experimental Status of the Chiral Magnetic Effect

“…In my view, the other big step forward for CME measurements in the last year is a recently published paper [19] by STAR using 2.4B events of 200 GeV Au + Au data. The event plane can be determined using the azimuthal angles of spectator nucleons (the "spectator" plane)that plane should be quite closely correlated with the direction of the event B-field which is mostly generated by the spectator protons, so measuring ∆γ relative to this plane should maximize the contribution from the CME.…”

“…Using ∆γ measurements from both of these planes, one can extract the fraction of the ∆γ that comes from CME under the assumption that the sole contributions are CME and v 2 -related background. Results from this STAR measurement [19] are shown in Figure 3 -each column of the figure represents the CME fraction ( f CME ) extracted from a slightly different version of the measurement, with each red point representing a result in mid-central collisions where we may expect the CME fraction to be maximized, and the blue points representing results in peripheral collisions for reference. A statistically significant f CME of around 10% is extracted in mid-central collisions, but there are concerns that non-flow may still contribute.…”

“…If the strange quark can be considered a light quark, then it will have the same net chirality in each event as the up and down quarks. Some of these strange quarks will go Figure 3: f CME , the fraction of the ∆γ that is due to CME, as determined by an analysis that compares correlations with the participant plane to those with the spectator plane [19]. Subevent analyses are performed to reduce the contribution of non-flow, as discussed in the text into the formation of Λ hyperons, which will then acquire a net helicity in each event caused by LPV.…”

Deciphering the phases of QCD matter with fluctuations and correlations of conserved charges

“…This is in particular essential at low energies because, in addition to the above mentioned arguments regarding binomial multiplicity distributions, most of these contributions scale with the net-proton number. For example, at LHC energies, where net-proton number at mid-rapidity is practically zero, contributions from wounded nucleon fluctuations are immaterial for the measured second order cumulants of net-protons, while at lower energies these contributions are substantial [11,15,16]. Coming back to Fig.…”

“…Fig. 1 shows the evolution with collision energy of the fourth to seconder order cumulants of net-proton distributions 1 as measured by the STAR [14,15] (black star symbols) and HADES [16] (magenta box) collaborations. The data points are contrasted with calculations within two different ensembles of statistical mechanics [13,17,18]: (i) Grand Canonical Ensemble (GCE) with the ideal gas EoS in the Boltzmann limit, represented with the dashed line along unity; (ii) Canonical Ensemble (CE), implemented in the full phase space, also using the ideal gas EoS.…”