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We present three-particle mixed-harmonic correlations $\la \cos (m\phi_a + n\phi_b - (m+n) \phi_c)\ra$ for harmonics $m,n=1-3$ for charged particles in $\sqrt{s_{NN}}=$200 GeV Au+Au collisions at RHIC. These measurements provide information on the three-dimensional structure of the initial collision zone and are important for constraining models of a subsequent low-viscosity quark-gluon plasma expansion phase. We investigate correlations between the first, second and third harmonics predicted as a consequence of fluctuations in the initial state. The dependence of the correlations on the pseudorapidity separation between particles show hints of a breaking of longitudinal invariance. We compare our results to a number of state-of-the art hydrodynamic calculations with different initial states and temperature dependent viscosities. These measurements provide important steps towards constraining the temperature dependent transport and the longitudinal structure of the initial state at RHIC.

2 data tables

Figure 2

Dependence of mixed harmonic correlators $C_{1,2,3}$ and $C_{2,2,4}$ on relative pseudorapidity.

Figure 3

Centrality dependence of mixed harmonic correlators $C_{m,n,m+n}$.

Charge-dependent pair correlations relative to a third particle in $p$+Au and $d$+Au collisions at RHIC

The STAR collaboration Adam, J. ; Adamczyk, L. ; Adams, J.R. ; et al.

Phys.Lett.B 798 (2019) 134975, 2019.

Inspire Record 1738942 DOI 10.17182/hepdata.105911

Quark interactions with topological gluon configurations can induce chirality imbalance and local parity violation in quantum chromodynamics. This can lead to electric charge separation along the strong magnetic field in relativistic heavy-ion collisions -- the chiral magnetic effect (CME). We report measurements by the STAR collaboration of a CME-sensitive observable in $p$+Au and $d$+Au collisions at 200 GeV, where the CME is not expected, using charge-dependent pair correlations relative to a third particle. We observe strong charge-dependent correlations similar to those measured in heavy-ion collisions. This bears important implications for the interpretation of the heavy-ion data.

10 data tables

Figure 1, p+Au, gamma correlator, opposite-sign

The $\gamma_{OS}$ correlators in p+Au collisions at $\sqrt{s_{NN}}=200$ GeV at RHIC as a function of multiplicity.

Figure 1, p+Au, gamma correlator, same-sign

The $\gamma_{SS}$ correlators in p+Au collisions at $\sqrt{s_{NN}}=200$ GeV at RHIC as a function of multiplicity.

Figure 1, d+Au, gamma correlator, opposite-sign

The $\gamma_{OS}$ correlators in d+Au collisions at $\sqrt{s_{NN}}=200$ GeV at RHIC as a function of multiplicity.

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Pair invariant mass to isolate background in the search for the chiral magnetic effect in Au+Au collisions at $\sqrt{s_{_{\rm NN}}}$= 200 GeV

The STAR collaboration Abdallah, M.S. ; Adam, J. ; Adamczyk, L. ; et al.

Phys.Rev.C 106 (2022) 034908, 2022.

Inspire Record 1800376 DOI 10.17182/hepdata.95210

Quark interactions with topological gluon configurations can induce local chirality imbalance and parity violation in quantum chromodynamics, which can lead to the chiral magnetic effect (CME) -- an electric charge separation along the strong magnetic field in relativistic heavy-ion collisions. The CME-sensitive azimuthal correlator observable ($\Delta\gamma$) is contaminated by background arising, in part, from resonance decays coupled with elliptic anisotropy ($v_{2}$). We report here differential measurements of the correlator as a function of the pair invariant mass ($m_{\rm inv}$) in 20-50% centrality Au+Au collisions at $\sqrt{s_{_{\rm NN}}}$= 200 GeV by the STAR experiment at RHIC. Strong resonance background contributions to $\Delta\gamma$ are observed. At large $m_{\rm inv}$ where this background is significantly reduced, the $\Delta\gamma$ value is found to be significantly smaller. An event-shape-engineering technique is deployed to determine the $v_{2}$ background shape as a function of $m_{\rm inv}$. We extract a $v_2$-independent and $m_{\rm inv}$-averaged signal $\Delta\gamma_{\rm sig}$ = (0.03 $\pm$ 0.06 $\pm$ 0.08) $\times10^{-4}$, or $(2\pm4\pm5)\%$ of the inclusive $\Delta\gamma(m_{\rm inv}>0.4$ GeV/$c^2$)$ =(1.58 \pm 0.02 \pm 0.02) \times10^{-4}$, within pion $p_{T}$ = 0.2 - 0.8~\gevc and averaged over pseudorapidity ranges of $-1 < \eta < -0.05$ and $0.05 < \eta < 1$. This represents an upper limit of $0.23\times10^{-4}$, or $15\%$ of the inclusive result, at $95\%$ confidence level for the $m_{\rm inv}$-integrated CME contribution.

9 data tables

Table for Figure 2(a)

The $m_{\rm inv}$ dependences of the OS and SS pion pair multiplicities in 20-50$\%$ Au+Au collisions at 200 GeV.

Table for Figure 2(b)

The $m_{\rm inv}$ dependences of the $\gamma_{OS}$, $\gamma_{SS}$ in 20-50$\%$ Au+Au collisions at 200 GeV.

Table for Figure 3(a)

$m_{\rm inv}$ dependences of the relative excess of OS over SS pion pairs in 20-50$\%$ Au+Au collisions at 200 GeV.

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ANGULAR DEPENDENCE OF THE POLARIZATION CORRELATION PARAMETER A(00NN) AND THE ASYMMETRY PARAMETER A(000N) IN ELASTIC PROTON PROTON SCATTERING AT 690-MEV - 950-MEV

Investigation of the Energy Dependence of the Spin Spin Correlation in the Diproton Resonance Region

CROSS-SECTION ASYMMETRY OF THE gamma n ---> pi- p REACTION BY POLARIZED PHOTONS IN THE THIRD AND FOURTH RESONANCE REGIONS

Energy Dependence of Total Cross-sections for Neutrino and Anti-neutrino Interactions at Energies Below 35-{GeV}

Limitations on Production Cross-section of Neutral Penetrating Particles in 70-{GeV}/c $p N$ Collisions

Z DEPENDENCE OF DIFFERENTIAL AND TOTAL CROSS-SECTIONS IN QUASIBINARY EXCHANGE REACTIONS ON NUCLEI pi- A(z) ---> (pi0, eta, omega, f2) + A*(z-1) AT 39.1-GeV/c

Inclusive prompt muon yields and charm production cross-section estimate at s**(1/2) = 11.5-GeV

Constraining the initial conditions and temperature dependent transport with three-particle correlations in Au+Au collisions

Charge-dependent pair correlations relative to a third particle in $p$+Au and $d$+Au collisions at RHIC

Pair invariant mass to isolate background in the search for the chiral magnetic effect in Au+Au collisions at $\sqrt{s_{_{\rm NN}}}$= 200 GeV