Pion, Kaon, and (Anti-)Proton Production in U+U Collisions at $\sqrt{s_{NN}}$ = 193 GeV in STAR

The STAR collaboration Abdallah, M.S. ; Aboona, B.E. ; Adam, J. ; et al.
Phys.Rev.C 107 (2023) 024901, 2023.
Inspire Record 2629622 DOI 10.17182/hepdata.132660

We present the first measurements of transverse momentum spectra of $\pi^{\pm}$, $K^{\pm}$, $p(\bar{p})$ at midrapidity ($|y| < 0.1$) in U+U collisions at $\sqrt{s_{NN}}$ = 193 GeV with the STAR detector at the Relativistic Heavy Ion Collider (RHIC). The centrality dependence of particle yields, average transverse momenta, particle ratios and kinetic freeze-out parameters are discussed. The results are compared with the published results from Au+Au collisions at $\sqrt{s_{NN}} =$ 200 GeV in STAR. The results are also compared to those from A Multi Phase Transport (AMPT) model.

20 data tables

'Identified transverse momentum spectra of $\pi^{+}$ at midrapidity (|y| < 0.1) in U+U collisions at $\sqrt{s_{\rm NN}}$ = 193 GeV'

'Identified transverse momentum spectra of $K^{+}$ at midrapidity (|y| < 0.1) in U+U collisions at $\sqrt{s_{\rm NN}}$ = 193 GeV'

'Identified transverse momentum spectra of p at midrapidity (|y| < 0.1) in U+U collisions at $\sqrt{s_{\rm NN}}$ = 193 GeV'

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Evidence for Nonlinear Gluon Effects in QCD and their $A$ Dependence at STAR

The STAR collaboration Abdallah, M.S. ; Aboona, B.E. ; Adam, J. ; et al.
Phys.Rev.Lett. 129 (2022) 092501, 2022.
Inspire Record 1972873 DOI 10.17182/hepdata.115421

The STAR Collaboration reports measurements of back-to-back azimuthal correlations of di-$\pi^0$s produced at forward pseudorapidities ($2.6<\eta<4.0$) in $p$+$p$, $p+$Al, and $p+$Au collisions at a center-of-mass energy of 200 GeV. We observe a clear suppression of the correlated yields of back-to-back $\pi^0$ pairs in $p+$Al and $p+$Au collisions compared to the $p$+$p$ data. The observed suppression of back-to-back pairs as a function of transverse momentum suggests nonlinear gluon dynamics arising at high parton densities. The larger suppression found in $p+$Au relative to $p+$Al collisions exhibits a dependence of the saturation scale, $Q_s^2$, on the mass number, $A$. A linear scaling of the suppression with $A^{1/3}$ is observed with a slope of $-0.09$$\pm$$0.01$.

15 data tables

The correlation functions (corrected for nonuniform detector efficiency in $\phi$; not corrected for the absolute detection efficiency) vs. azimuthal angle difference between forward ($2.6<\eta<4.0$) $\pi^{0}$s in $p$+$p$ collisions at $\sqrt{s_{\mathrm{_{NN}}}}=200$ GeV at low $p_{T}$ ($p^{trig}_{T}$=2-2.5 GeV/c, $p^{asso}_{T}$=1-1.5 GeV/c)

The correlation functions (corrected for nonuniform detector efficiency in $\phi$; not corrected for the absolute detection efficiency) vs. azimuthal angle difference between forward ($2.6<\eta<4.0$) $\pi^{0}$s in $p+$Al collisions at $\sqrt{s_{\mathrm{_{NN}}}}=200$ GeV at low $p_{T}$ ($p^{trig}_{T}$=2-2.5 GeV/c, $p^{asso}_{T}$=1-1.5 GeV/c)

The correlation functions (corrected for nonuniform detector efficiency in $\phi$; not corrected for the absolute detection efficiency) vs. azimuthal angle difference between forward ($2.6<\eta<4.0$) $\pi^{0}$s in $p+$Au collisions at $\sqrt{s_{\mathrm{_{NN}}}}=200$ GeV at low $p_{T}$ ($p^{trig}_{T}$=2-2.5 GeV/c, $p^{asso}_{T}$=1-1.5 GeV/c)

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Search for the chiral magnetic effect via charge-dependent azimuthal correlations relative to spectator and participant planes in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV

The STAR collaboration Abdallah, M.S. ; Adam, J. ; Adamczyk, L. ; et al.
Phys.Rev.Lett. 128 (2022) 092301, 2022.
Inspire Record 1869023 DOI 10.17182/hepdata.127969

The chiral magnetic effect (CME) refers to charge separation along a strong magnetic field due to imbalanced chirality of quarks in local parity and charge-parity violating domains in quantum chromodynamics. The experimental measurement of the charge separation is made difficult by the presence of a major background from elliptic azimuthal anisotropy. This background and the CME signal have different sensitivities to the spectator and participant planes, and could thus be determined by measurements with respect to these planes. We report such measurements in Au+Au collisions at a nucleon-nucleon center-of-mass energy of 200 GeV at the Relativistic Heavy-Ion Collider. It is found that the charge separation, with the flow background removed, is consistent with zero in peripheral (large impact parameter) collisions. Some indication of finite CME signals is seen in mid-central (intermediate impact parameter) collisions. Significant residual background effects may, however, still be present.

16 data tables

The centrality dependencies of the $v_{2}\{\psi_\mathrm{TPC}\}$ for Au+Au collision at $\sqrt{s_{\rm NN}}$=200 GeV.

The centrality dependencies of the $v_{2}\{\psi_\mathrm{ZDC}\}$ for Au+Au collision at $\sqrt{s_{\rm NN}}$=200 GeV.

The centrality dependencies of the $\Delta\gamma\{\psi_\mathrm{TPC}\}$ for Au+Au collision at $\sqrt{s_{\rm NN}}$=200 GeV.

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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

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

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

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

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Multi-particle azimuthal correlations in p-Pb and Pb-Pb collisions at the LHC

The ALICE collaboration Abelev, Betty Bezverkhny ; Adam, Jaroslav ; Adamova, Dagmar ; et al.
Phys.Rev.C 90 (2014) 054901, 2014.
Inspire Record 1300038 DOI 10.17182/hepdata.65710

Measurements of multi-particle azimuthal correlations (cumulants) for charged particles in p-Pb and Pb-Pb collisions are presented. They help address the question of whether there is evidence for global, flow-like, azimuthal correlations in the p-Pb system. Comparisons are made to measurements from the larger Pb-Pb system, where such evidence is established. In particular, the second harmonic two-particle cumulants are found to decrease with multiplicity, characteristic of a dominance of few-particle correlations in p-Pb collisions. However, when a $|\Delta \eta|$ gap is placed to suppress such correlations, the two-particle cumulants begin to rise at high-multiplicity, indicating the presence of global azimuthal correlations. The Pb-Pb values are higher than the p-Pb values at similar multiplicities. In both systems, the second harmonic four-particle cumulants exhibit a transition from positive to negative values when the multiplicity increases. The negative values allow for a measurement of $v_{2}\{4\}$ to be made, which is found to be higher in Pb-Pb collisions at similar multiplicities. The second harmonic six-particle cumulants are also found to be higher in Pb-Pb collisions. In Pb-Pb collisions, we generally find $v_{2}\{4\} \simeq v_{2}\{6\}\neq 0$ which is indicative of a Bessel-Gaussian function for the $v_{2}$ distribution. For very high-multiplicity Pb-Pb collisions, we observe that the four- and six-particle cumulants become consistent with 0. Finally, third harmonic two-particle cumulants in p-Pb and Pb-Pb are measured. These are found to be similar for overlapping multiplicities, when a $|\Delta\eta| > 1.4$ gap is placed.

42 data tables

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K*0 production in Cu+Cu and Au+Au collisions at \sqrt{s_NN} = 62.4 GeV and 200 GeV

The STAR collaboration Aggarwal, M.M. ; Ahammed, Z. ; Alakhverdyants, A.V. ; et al.
Phys.Rev.C 84 (2011) 034909, 2011.
Inspire Record 857694 DOI 10.17182/hepdata.102405

We report on K*0 production at mid-rapidity in Au+Au and Cu+Cu collisions at \sqrt{s_{NN}} = 62.4 and 200 GeV collected by the Solenoid Tracker at RHIC (STAR) detector. The K*0 is reconstructed via the hadronic decays K*0 \to K+ pi- and \bar{K*0} \to K-pi+. Transverse momentum, pT, spectra are measured over a range of pT extending from 0.2 GeV/c to 5 GeV/c. The center of mass energy and system size dependence of the rapidity density, dN/dy, and the average transverse momentum, <pT>, are presented. The measured N(K*0)/N(K) and N(\phi)/N(K*0) ratios favor the dominance of re-scattering of decay daughters of K*0 over the hadronic regeneration for the K*0 production. In the intermediate pT region (2.0 < pT < 4.0 GeV/c), the elliptic flow parameter, v2, and the nuclear modification factor, RCP, agree with the expectations from the quark coalescence model of particle production.

64 data tables

The K$\pi$ pair invariant mass distribution integrated over the $K^{*0}$ $p_T$ for minimum bias Au+Au collisions at $\sqrt{s_{NN}}$ =200 GeV after mixed-event background subtraction.

The K$\pi$ pair invariant mass distribution integrated over the $K^{*0}$ $p_T$ for minimum bias Au+Au collisions at $\sqrt{s_{NN}}$ =62.4 GeV after mixed-event background subtraction.

The K$\pi$ pair invariant mass distribution integrated over the $K^{*0}$ $p_T$ for minimum bias Cu+Cu collisions at $\sqrt{s_{NN}}$ =200 GeV after mixed-event background subtraction.

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Higher Moments of Net-proton Multiplicity Distributions at RHIC

The STAR collaboration Aggarwal, M.M. ; Ahammed, Z. ; Alakhverdyants, A.V. ; et al.
Phys.Rev.Lett. 105 (2010) 022302, 2010.
Inspire Record 853304 DOI 10.17182/hepdata.73344

We report the first measurements of the kurtosis (\kappa), skewness (S) and variance (\sigma^2) of net-proton multiplicity (N_p - N_pbar) distributions at midrapidity for Au+Au collisions at \sqrt(s_NN) = 19.6, 62.4, and 200 GeV corresponding to baryon chemical potentials (\mu_B) between 200 - 20 MeV. Our measurements of the products \kappa \sigma^2 and S \sigma, which can be related to theoretical calculations sensitive to baryon number susceptibilities and long range correlations, are constant as functions of collision centrality. We compare these products with results from lattice QCD and various models without a critical point and study the \sqrt(s_NN) dependence of \kappa \sigma^2. From the measurements at the three beam energies, we find no evidence for a critical point in the QCD phase diagram for \mu_B below 200 MeV.

40 data tables

$\Delta N_p$ multiplicity distribution in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV for 0-5 percent central collisions at midrapidity (| y |< 0.5).

$\Delta N_p$ multiplicity distribution in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV for 30-40 percent central collisions at midrapidity (| y |< 0.5).

$\Delta N_p$ multiplicity distribution in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV for 70-80 percent central collisions at midrapidity (| y |< 0.5).

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A-DEPENDENCE OF CUMULATIVE PHOTOPROTONS

Alanakian, K.V. ; Amarian, M.D. ; Demirchyan, R.A. ; et al.
EFI-471-14-81-YEREVAN, 1981.
Inspire Record 167330 DOI 10.17182/hepdata.18454

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3 data tables

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