Multi-particle azimuthal correlations for extracting event-by-event elliptic and triangular flow in Au$+$Au collisions at $\sqrt{s_{_{NN}}}=200$ GeV

The PHENIX collaboration Adare, A. ; Aidala, C. ; Ajitanand, N.N. ; et al.
Phys.Rev.C 99 (2019) 024903, 2019.
Inspire Record 1670164 DOI 10.17182/hepdata.150019

We present measurements of elliptic and triangular azimuthal anisotropy of charged particles detected at forward rapidity $1<|\eta|<3$ in Au$+$Au collisions at $\sqrt{s_{_{NN}}}=200$ GeV, as a function of centrality. The multiparticle cumulant technique is used to obtain the elliptic flow coefficients $v_2\{2\}$, $v_2\{4\}$, $v_2\{6\}$, and $v_2\{8\}$, and triangular flow coefficients $v_3\{2\}$ and $v_3\{4\}$. Using the small-variance limit, we estimate the mean and variance of the event-by-event $v_2$ distribution from $v_2\{2\}$ and $v_2\{4\}$. In a complementary analysis, we also use a folding procedure to study the distributions of $v_2$ and $v_3$ directly, extracting both the mean and variance. Implications for initial geometrical fluctuations and their translation into the final state momentum distributions are discussed.

21 data tables

Centrality dependence of (a) $v_2${2} and (b) $v_2${4}. (a) The red points indicate no pseudorapidity gap whereas the magenta points indicate a pseudorapidity gap of |$\Delta\eta$| > 2.0. (b) The black points indicate $v_2${4} with no pseudorapidity gap, the blue points indicate a two-subevent method with |$\Delta\eta$| > 2.0 but where some short-range pairs are allowed, and the red points indicate a two-subevent method with |$\Delta\eta$| > 2.0 where no short-range pairs are allowed.

Centrality dependence of (a) $v_2${2} and (b) $v_2${4}. (a) The red points indicate no pseudorapidity gap whereas the magenta points indicate a pseudorapidity gap of |$\Delta\eta$| > 2.0. (b) The black points indicate $v_2${4} with no pseudorapidity gap, the blue points indicate a two-subevent method with |$\Delta\eta$| > 2.0 but where some short-range pairs are allowed, and the red points indicate a two-subevent method with |$\Delta\eta$| > 2.0 where no short-range pairs are allowed.

Centrality dependence of (a) $v_2${2} and (b) $v_2${4}. (a) The red points indicate no pseudorapidity gap whereas the magenta points indicate a pseudorapidity gap of |$\Delta\eta$| > 2.0. (b) The black points indicate $v_2${4} with no pseudorapidity gap, the blue points indicate a two-subevent method with |$\Delta\eta$| > 2.0 but where some short-range pairs are allowed, and the red points indicate a two-subevent method with |$\Delta\eta$| > 2.0 where no short-range pairs are allowed.

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Systematic Study of Azimuthal Anisotropy in Cu$+$Cu and Au$+$Au Collisions at $\sqrt{s_{_{NN}}} = 62.4$ and 200 GeV

The PHENIX collaboration Adare, A. ; Afanasiev, S. ; Aidala, C. ; et al.
Phys.Rev.C 92 (2015) 034913, 2015.
Inspire Record 1332240 DOI 10.17182/hepdata.150018

We have studied the dependence of azimuthal anisotropy $v_2$ for inclusive and identified charged hadrons in Au$+$Au and Cu$+$Cu collisions on collision energy, species, and centrality. The values of $v_2$ as a function of transverse momentum $p_T$ and centrality in Au$+$Au collisions at $\sqrt{s_{_{NN}}}$=200 GeV and 62.4 GeV are the same within uncertainties. However, in Cu$+$Cu collisions we observe a decrease in $v_2$ values as the collision energy is reduced from 200 to 62.4 GeV. The decrease is larger in the more peripheral collisions. By examining both Au$+$Au and Cu$+$Cu collisions we find that $v_2$ depends both on eccentricity and the number of participants, $N_{\rm part}$. We observe that $v_2$ divided by eccentricity ($\varepsilon$) monotonically increases with $N_{\rm part}$ and scales as ${N_{\rm part}^{1/3}}$. The Cu$+$Cu data at 62.4 GeV falls below the other scaled $v_{2}$ data. For identified hadrons, $v_2$ divided by the number of constituent quarks $n_q$ is independent of hadron species as a function of transverse kinetic energy $KE_T=m_T-m$ between $0.1<KE_T/n_q<1$ GeV. Combining all of the above scaling and normalizations, we observe a near-universal scaling, with the exception of the Cu$+$Cu data at 62.4 GeV, of $v_2/(n_q\cdot\varepsilon\cdot N^{1/3}_{\rm part})$ vs $KE_T/n_q$ for all measured particles.

75 data tables

$v_2$ for inclusive charged hadrons in Au+Au at $\sqrt{s_{NN}}$ = 200 GeV.

$v_2$ for inclusive charged hadrons in Au+Au at $\sqrt{s_{NN}}$ = 200 GeV.

$v_2$ for inclusive charged hadrons in Au+Au at $\sqrt{s_{NN}}$ = 200 GeV.

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Modification of charged-particle jets in event-shape engineered Pb$-$Pb collisions at $\sqrt{s_{\rm NN}} = 5$ TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Aglieri Rinella, Gianluca ; et al.
Phys.Lett.B 851 (2024) 138584, 2024.
Inspire Record 2681682 DOI 10.17182/hepdata.150418

Charged-particle jet yields have been measured in semicentral Pb$-$Pb collisions at center-of-mass energy per nucleon-nucleon collision $\sqrt{s_{\rm NN}} = 5$ TeV with the ALICE detector at the LHC. These yields are reported as a function of the jet transverse momentum, and further classified by their angle with respect to the event plane and the event shape, characterized by ellipticity, in an effort to study the path-length dependence of jet quenching. Jets were reconstructed at midrapidity from charged-particle tracks using the anti-$k_{\rm T}$ algorithm with resolution parameters $R =$ 0.2 and 0.4, with event-plane angle and event-shape values determined using information from forward scintillating detectors. The results presented in this letter show that, in semicentral Pb$-$Pb collisions, there is no significant difference between jet yields in predominantly isotropic and elliptical events. However, out-of-plane jets are observed to be more suppressed than in-plane jets. Further, this relative suppression is greater for low transverse momentum ($<$ 50 GeV/$c$) $R =$ 0.2 jets produced in elliptical events, with out-of-plane to in-plane jet-yield ratios varying up to 5.2$\sigma$ between different event-shape classes. These results agree with previous studies indicating that jets experience azimuthally anisotropic suppression when traversing the QGP medium, and can provide additional constraints on the path-length dependence of jet energy loss.

6 data tables

Charged-particle jet yields, R=0.2

Charged-particle jet yields, R=0.4

q2-large/q2-small, R=0.2

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Version 2
Enhanced deuteron coalescence probability in jets

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adler, Alexander ; et al.
Phys.Rev.Lett. 131 (2023) 042301, 2023.
Inspire Record 2601274 DOI 10.17182/hepdata.141173

The transverse-momentum ($p_{\rm T}$) spectra and coalescence parameters $B_2$ of (anti)deuterons are measured in pp collisions at $\sqrt{s} = 13$ TeV for the first time in and out of jets. In this measurement, the direction of the leading particle with the highest $p_{\rm T}$ in the event ($p_{\rm T}^{\rm{ lead}} > 5$ GeV/$c$) is used as an approximation for the jet axis. The event is consequently divided into three azimuthal regions and the jet signal is obtained as the difference between the Toward region, that contains jet fragmentation products in addition to the underlying event (UE), and the Transverse region, which is dominated by the UE. The coalescence parameter in the jet is found to be approximately a factor of 10 larger than that in the underlying event. This experimental observation is consistent with the coalescence picture and can be attributed to the smaller average phase-space distance between nucleons inside the jet cone as compared to the underlying event. The results presented in this Letter are compared to predictions from a simple nucleon coalescence model, where the phase space distributions of nucleons are generated using PYTHIA 8 with the Monash 2013 tuning, and to predictions from a deuteron production model based on ordinary nuclear reactions with parametrized energy-dependent cross sections tuned on data. The latter model is implemented in PYTHIA 8.3. Both models reproduce the observed large difference between in-jet and out-of-jet coalescence parameters, although the almost flat trend of the $B^{\rm Jet}_2$ is not reproduced by the models, which instead give a decreasing trend.

6 data tables

Transverse momentum spectra for the transverse azimuthal regions. Events with a leading track with PT>5 GEV at midrapidity are selected. The spectrum is shown in Figure 1 (left panel).

Transverse momentum spectra for the toward azimuthal regions. Events with a leading track with PT>5 GEV at midrapidity are selected. The spectrum is shown in Figure 1 (left panel).

Transverse momentum spectra for the away azimuthal regions. Events with a leading track with PT>5 GEV at midrapidity are selected. The spectrum is shown in Figure 1 (left panel).

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K$^{*}$(892)$^{\pm}$ resonance production in Pb$-$Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Aglieri Rinella, Gianluca ; et al.
CERN-EP-2023-176, 2023.
Inspire Record 2692205 DOI 10.17182/hepdata.150017

The production of K$^*$(892)$^\pm$ meson resonance is measured at midrapidity ($|y|<0.5$) in Pb-Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV using the ALICE detector at the LHC. The resonance is reconstructed via its hadronic decay channel K$^*$(892)$^\pm \rightarrow \rm{K^0_S \pi^\pm}$. The transverse momentum distributions are obtained for various centrality intervals in the $p_{\rm T}$ range of 0.4-16 GeV/$c$. The reported measurements of integrated yields, mean transverse momenta, and particle yield ratios are consistent with previous ALICE measurements for K$^*$(892)$^0$. The $p_{\rm T}$-integrated yield ratio 2K$^*$(892)$^\pm$/($\rm{K^+ + K^-}$) in central Pb-Pb collisions shows a significant suppression (9.3$\sigma$) relative to pp collisions. Thermal model calculations overpredict the particle yield ratio. Although both simulations consider the hadronic phase, only HRG-PCE accurately represents the measurements, whereas MUSIC+SMASH tends to overpredict them. These observations, along with the kinetic freeze-out temperatures extracted from the yields of light-flavored hadrons using the HRG-PCE model, indicate a finite hadronic phase lifetime, which increases towards central collisions. The $p_{\rm T}$-differential yield ratios 2K$^*$(892)$^\pm$/($\rm{K^+ + K^-}$) and 2K$^*$(892)$^\pm$/($\rm{\pi^+ + \pi^-}$) are suppressed by up to a factor of five at $p_{\rm T}<2$ GeV/$c$ in central Pb-Pb collisions compared to pp collisions at $\sqrt{s} =$ 5.02 TeV. Both particle ratios and are qualitatively consistent with expectations for rescattering effects in the hadronic phase. The nuclear modification factor shows a smooth evolution with centrality and is below unity at $p_{\rm T}>8$ GeV/$c$, consistent with measurements for other light-flavored hadrons. The smallest values are observed in most central collisions, indicating larger energy loss of partons traversing the dense medium.

17 data tables

$p_{\rm T}$-distributions of $\rm{K}^{*}$ (average of particle and anti-particle) meson measured in Pb-Pb collisions at \sqrt{s_{NN}}$ = 5.02 TeV for 0-10\% centrality.

$p_{\rm T}$-distributions of $\rm{K}^{*}$ (average of particle and anti-particle) meson measured in Pb-Pb collisions at \sqrt{s_{NN}}$ = 5.02 TeV for 10-20\% centrality.

$p_{\rm T}$-distributions of $\rm{K}^{*}$ (average of particle and anti-particle) meson measured in Pb-Pb collisions at \sqrt{s_{NN}}$ = 5.02 TeV for 20-40\% centrality.

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Version 3
Beam Energy Dependence of Fifth and Sixth-Order Net-proton Number Fluctuations in Au+Au Collisions at RHIC

The STAR collaboration Aboona, Bassam ; Adam, Jaroslav ; Adamczyk, Leszek ; et al.
Phys.Rev.Lett. 130 (2023) 082301, 2023.
Inspire Record 2119969 DOI 10.17182/hepdata.132661

We report the beam energy and collision centrality dependence of fifth and sixth order cumulants ($C_{5}$, $C_{6}$) and factorial cumulants ($\kappa_{5}$, $\kappa_{6}$) of net-proton and proton distributions, from $\sqrt{s_{NN}} = 3 - 200$ GeV Au+Au collisions at RHIC. The net-proton cumulant ratios generally follow the hierarchy expected from QCD thermodynamics, except for the case of collisions at $\sqrt{s_{NN}}$ = 3 GeV. $C_{6}/C_{2}$ for 0-40% centrality collisions is increasingly negative with decreasing $\sqrt{s_{NN}}$, while it is positive for the lowest $\sqrt{s_{NN}}$ studied. These observed negative signs are consistent with QCD calculations (at baryon chemical potential, $\mu_{B} \leq$ 110 MeV) that include a crossover quark-hadron transition. In addition, for $\sqrt{s_{NN}} \geq$ 11.5 GeV, the measured proton $\kappa_{n}$, within uncertainties, does not support the two-component shape of proton distributions that would be expected from a first-order phase transition. Taken in combination, the hyper-order proton number fluctuations suggest that the structure of QCD matter at high baryon density, $\mu_{B}\sim 750$ MeV ($\sqrt{s_{NN}}$ = 3 GeV) is starkly different from those at vanishing $\mu_{B}\sim 20$MeV ($\sqrt{s_{NN}}$ = 200 GeV and higher).

9 data tables

Event-by-event proton multiplicity distributions for 0-40$\%$, 0-5$\%$ and 50-60$\%$ Au+Au collisions at $\sqrt{s_{NN}} = 3 GeV. The distributions are not corrected for proton and antiproton detection efficiency.

Proton factorial cumulants K4, K5 and K6 in 0-40$\%$ and 50-60$\%$ Au+Au collisions from $\sqrt{s_{NN}}$ = 3 - 200 GeV. At $\sqrt{s_{NN}}$ = 3 GeV, measurement is done with halfrapdity coverage (-0.5 $<$ y $<$ 0) while for rest of energies the rapidity coverage is (-0.5 $<$ y $<$ -0.5).

Proton factorial cumulants K4, K5 and K6 from UrQMD model (0-40$\%$ and 50-60$\%$ centrality) for Au+Au collisions from $\sqrt{s_{NN}}$ = 3 - 200 GeV. UrQMD calculation for 3 GeVis with rapidity coverage (-0.5 $<$ y $<$ 0) while for rest of energies the rapidity coverage is (-0.5 $<$ y $<$ -0.5). In addition, two-component model (0-40$\%$) calculations for facorial cumulants are also given.

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Extraction of neutron density distributions from high-statistics coherent elastic neutrino-nucleus scattering data

Sierra, D. Aristizabal ;
Phys.Lett.B 845 (2023) 138140, 2023.
Inspire Record 2628373 DOI 10.17182/hepdata.150020

Forthcoming fixed-target coherent elastic neutrino-nucleus scattering experiments aim at measurements with $\cal{O}(\text{tonne})$-scale detectors and substantially reduced systematic and statistical uncertainties. With such high quality data, the extraction of point-neutron distributions mean-square radii requires a better understanding of possible theoretical uncertainties. We quantify the impact of single-nucleon electromagnetic mean-square radii on the weak-charge form factor and compare results from weak-charge form factor parametrizations and weak-charge form factor decompositions in terms of elastic vector proton and neutron form factors, including nucleon form factors $Q$-dependent terms up to order $Q^2$. We assess as well the differences arising from results derived using weak-charge form factor decompositions in terms of elastic vector proton and neutron form factors and a model-independent approach based solely on the assumption of spherically symmetric nuclear ground state. We demonstrate the impact of the main effects by assuming pseudo-data from a one-tonne LAr detector and find that, among the effects and under the assumptions considered in this paper, weak-charge form factor parametrizations and weak-charge form factor decompositions in terms of elastic vector proton and neutron form factors enable the extraction of the $^{40}\text{Ar}$ point-neutron distribution mean-square radius with a $\sim 15\%$ accuracy. With a substantial reduction of the beam-related neutron and steady-state backgrounds a $\sim 1\%$ precision extraction seems feasible, using either of the two approaches.

2 data tables

$z_{\parallel}^{\rm{ch}}$ for $\Lambda_{\rm{c}}^{+}$-tagged jets and D$^{0}$-tagged jets in the $p_{\rm{T}}^{\rm{jet\text{ }ch}}$: 7-15 GeV/$c$ interval.

$z_{\parallel}^{\rm{ch}}$ ratio of $\Lambda_{\rm{c}}^{+}$-tagged jets and D$^{0}$-tagged jets in the $p_{\rm{T}}^{\rm{jet\text{ }ch}}$: 7-15 GeV/$c$ interval.


Single identified hadron spectra from s(NN)**1/2 = 130-GeV Au + Au collisions.

The PHENIX collaboration Adcox, K. ; Adler, S.S. ; Ajitanand, N.N. ; et al.
Phys.Rev.C 69 (2004) 024904, 2004.
Inspire Record 623413 DOI 10.17182/hepdata.149578

Transverse momentum spectra and yields of hadrons are measured by the PHENIX collaboration in Au + Au collisions at sqrt(s_NN) = 130 GeV at the Relativistic Heavy Ion Collider (RHIC). The time-of-flight resolution allows identification of pions to transverse momenta of 2 GeV/c and protons and antiprotons to 4 GeV/c. The yield of pions rises approximately linearly with the number of nucleons participating in the collision, while the number of kaons, protons, and antiprotons increases more rapidly. The shape of the momentum distribution changes between peripheral and central collisions. Simultaneous analysis of all the p_T spectra indicates radial collective expansion, consistent with predictions of hydrodynamic models. Hydrodynamic analysis of the spectra shows that the expansion velocity increases with collision centrality and collision energy. This expansion boosts the particle momenta, causing the yield from soft processes to exceed that for hard to large transverse momentum, perhaps as large as 3 GeV/c.

30 data tables

The sources of systematic uncertainties in $\langle p_T \rangle$ and $dN$/$dy$.

The $dN$/$dy$ at midrapidity for hadrons produced at midrapidity in each centrality class.

The resulting inverse slopes in MeV after fitting an $m_T$ exponential to the spectra in the range $m_T$-$m_0$ < 1 GeV in each event centrality classes. The pion resonance region is excluded in the fits. The equivalent $p_T$ fit range for each particle is shown accordingly.

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Centrality dependence of charged hadron production in deuteron+gold and nucleon+gold collisions at sqrt(s_NN)=200 GeV

The PHENIX collaboration Adler, S.S. ; Afanasiev, S. ; Aidala, C. ; et al.
Phys.Rev.C 77 (2008) 014905, 2008.
Inspire Record 758544 DOI 10.17182/hepdata.146750

We present transverse momentum (p_T) spectra of charged hadrons measured in deuteron-gold and nucleon-gold collisions at \sqrts = 200 GeV for four centrality classes. Nucleon-gold collisions were selected by tagging events in which a spectator nucleon was observed in one of two forward rapidity detectors. The spectra and yields were investigated as a function of the number of binary nucleon-nucleon collisions, \nu, suffered by deuteron nucleons. A comparison of charged particle yields to those in p+p collisions show that the yield per nucleon-nucleon collision saturates with \nu for high momentum particles. We also present the charged hadron to neutral pion ratios as a function of p_T.

21 data tables

<p>Charged hadron spectra for centrality selected d+Au collisions.</p>

<p>Charged hadron spectra for centrality selected d+Au collisions.</p>

<p>Charged hadron spectra for centrality selected d+Au collisions.</p>

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Reaction plane correlated triangular flow in Au+Au collisions at $\mathbf{\sqrt{s_{\textrm{NN}}}=3}$ GeV

The STAR collaboration
2023.
Inspire Record 2702151 DOI 10.17182/hepdata.144480

We measure triangular flow relative to the reaction plane at 3 GeV center-of-mass energy in Au+Au collisions at RHIC. A significant $v_3$ signal is observed for protons, whose magnitude increases for higher rapidity, higher transverse momentum, and more peripheral collisions. The triangular flow is essentially rapidity-odd with a rapidity slope at mid-rapidity, $dv_3/dy|_{(y=0)}$, opposite in sign compared to the slope for directed flow. No significant $v_3$ signal is observed for charged pions and kaons. Comparisons with models suggest that a mean field potential is required to describe these results, and that the triangular shape of the participant nucleons is the result of stopping and nuclear geometry.

6 data tables

Event plane resolutions for calculating $v_3\{\Psi_1\}$ as a function of centrality from $\sqrt{s_{\textrm{NN}}}=3$ GeV Au+Au collisions at STAR.

$v_3\{\Psi_1\}$ vs. centrality for $\pi^+$, $\pi^-$, and protons using the event plane method in $\sqrt{s_{\textrm{NN}}}=3$ GeV Au+Au collisions at STAR.

$v_3\{\Psi_1\}$ vs. centrality for $K^+$, and $K^-$ using the event plane method in $\sqrt{s_{\textrm{NN}}}=3$ GeV Au+Au collisions at STAR.

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