Date

Light neutral-meson production in pp collisions at $\sqrt{s}$ = 13 TeV

The ALICE collaboration Acharya, Shreyasi ; Agarwal, Apar ; Aglieri Rinella, Gianluca ; et al.
JHEP 08 (2025) 035, 2025.
Inspire Record 2848478 DOI 10.17182/hepdata.160597

The momentum-differential invariant cross sections of ${\pi^{0}}$ and $\eta$ mesons are reported for pp collisions at $\sqrt{s}$ = 13 TeV at midrapidity ($|y|<0.8$). The measurement is performed in a broad transverse-momentum range of $0.2<p_{\rm T}<200$ GeV/$c$ and $0.4<p_{\rm T}<60$ GeV/$c$ for the ${\pi^{0}}$ and $\eta$, respectively, extending the $p_{\rm T}$ coverage of previous measurements. Transverse-mass-scaling violation of up to 60% at low transverse momentum has been observed, agreeing with measurements at lower collision energies. Transverse Bjorken $x$ ($x_{\rm T}$) scaling of the ${\pi^{0}}$ cross sections at LHC energies is fulfilled with a power-law exponent of $n$ = 5.01$\pm$0.05, consistent with values obtained for charged pions at similar collision energies. The data is compared to predictions from next-to-leading order perturbative QCD calculations, where the ${\pi^{0}}$ spectrum is best described using the CT18 parton distribution function and the NNFF1.0 or BDSS fragmentation function. Expectations from PYTHIA8 and EPOS LHC overestimate the spectrum for the ${\pi^{0}}$ and are not able to describe the shape and magnitude of the $\eta$ spectrum. The charged-particle multiplicity dependent ${\pi^{0}}$ and $\eta$ $p_{\rm T}$ spectra show the expected hardening with increasing multiplicity. This is demonstrated across a broad transverse-momentum range and up to events with a charged-particle multiplicity exceeding five times the mean value in minimum bias collisions. The absolute magnitude of the $\eta/\pi^{0}$ ratio shows a dependence on the charged-particle multiplicity for $p_{\rm T}<4$ GeV/$c$, qualitatively described by PYTHIA8 and EPOS LHC due to a rising contribution from feed-down of heavier particles to the ${\pi^{0}}$ spectrum.

94 data tables

Invariant differential cross section of the $\pi^{0}$ versus transverse momentum for pp collisions at $\sqrt{s}$ = 13 TeV.

Invariant differential cross section of the $\eta$ meson versus transverse momentum for pp collisions at $\sqrt{s}$ = 13 TeV.

The $\eta/\pi^{0}$ ratio as a function of $p_{\rm T}$ for pp collisions at $\sqrt{s}$ = 13 TeV.

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Measurement of $\omega$ meson production in pp collisions at $\sqrt{s}$ = 13 TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Agarwal, Apar ; et al.
JHEP 04 (2025) 067, 2025.
Inspire Record 2848263 DOI 10.17182/hepdata.157865

The $p_{\rm T}$-differential cross section of $\omega$ meson production in pp collisions at $\sqrt{s}= 13$ TeV at midrapidity ($|y|<0.5$) was measured with the ALICE detector at the LHC, covering an unprecedented transverse-momentum range of $1.6 <p_{\rm T}< 50$ GeV/$c$. The meson is reconstructed via the $\omega\rightarrow\pi^+\pi^-\pi^0$ decay channel. The results are compared with various theoretical calculations: PYTHIA8.2 with the Monash 2013 tune overestimates the data by up to 50%, whereas good agreement is observed with Next-to-Leading Order (NLO) calculations incorporating $\omega$ fragmentation using a broken SU(3) model. The $\omega/\pi^0$ ratio is presented and compared with theoretical calculations and the available measurements at lower collision energies. The presented data triples the $p_{\rm T}$ ranges of previously available measurements. A constant ratio of $C^{\omega/\pi^0}=0.578\pm0.006~\text{(stat.)}\pm 0.013~\text{(syst.)}$ is found above a transverse momentum of $4$ GeV/$c$, which is in agreement with previous findings at lower collision energies within the systematic and statistical uncertainties.

2 data tables

Invariant differential cross section of OMEGA mesons produced in inelastic pp collisions at center-of-mass energy 13 TeV, the uncertainty of sigma_{MB} of 1.58% is not included in the systematic error.

The measured ratio of cross sections for inclusive OMEGA to PI0 production at a centre-of-mass energy of 13 TeV.


System size and energy dependence of the mean transverse momentum fluctuations at the LHC

The ALICE collaboration Acharya, Shreyasi ; Agarwal, Apar ; Aglieri Rinella, Gianluca ; et al.
Eur.Phys.J.C 85 (2025) 776, 2025.
Inspire Record 2848476 DOI 10.17182/hepdata.159277

Event-by-event fluctuations of the event-wise mean transverse momentum, $\langle p_{\mathrm{T}}\rangle$, of charged particles produced in proton$-$proton (pp) collisions at $\sqrt{s}$ = 5.02 TeV, Xe$-$Xe collisions at $\sqrt{s_{\mathrm{NN}}} =$ 5.44 TeV, and Pb$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}} =$ 5.0 TeV are studied using the ALICE detector based on the integral correlator $\langle\langle Δp_{\rm T}Δp_{\rm T}\rangle\rangle $. The correlator strength is found to decrease monotonically with increasing produced charged-particle multiplicity measured at midrapidity in all three systems. In Xe$-$Xe and Pb$-$Pb collisions, the multiplicity dependence of the correlator deviates significantly from a simple power-law scaling as well as from the predictions of the HIJING and AMPT models. The observed deviation from power-law scaling is expected from transverse radial flow in semicentral to central Xe$-$Xe and Pb$-$Pb collisions. In pp collisions, the correlation strength is also studied by classifying the events based on the transverse spherocity, $S_0$, of the particle production at midrapidity, used as a proxy for the presence of a pronounced back-to-back jet topology. Low-spherocity (jetty) events feature a larger correlation strength than those with high spherocity (isotropic). The strength and multiplicity dependence of jetty and isotropic events are well reproduced by calculations with the PYTHIA 8 and EPOS LHC models.

12 data tables

Normalized transverse momentum correlator, $\sqrt{ \langle\langle \Delta p_{{\rm T}1}\Delta p_{{\rm T}2} \rangle\rangle }$$/\langle\langle p_{\rm T} \rangle\rangle $, as a function of the charged-particle multiplicity density, $\langle{\rm d}N_{\rm ch}/{\rm d}\eta \rangle$, in pp collisions at $\sqrt{s}$ = 5.02 TeV.

Normalized transverse momentum correlator, $\sqrt{ \langle\langle \Delta p_{{\rm T}1}\Delta p_{{\rm T}2} \rangle\rangle }$$/\langle\langle p_{\rm T} \rangle\rangle $, as a function of the charged-particle multiplicity density, $\langle{\rm d}N_{\rm ch}/{\rm d}\eta \rangle$, in Pb--Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV.

Normalized transverse momentum correlator, $\sqrt{ \langle\langle \Delta p_{{\rm T}1}\Delta p_{{\rm T}2} \rangle\rangle }$$/\langle\langle p_{\rm T} \rangle\rangle $, as a function of the charged-particle multiplicity density, $\langle{\rm d}N_{\rm ch}/{\rm d}\eta \rangle$, in Xe--Xe collisions at $\sqrt{s_{\rm NN}}$ = 5.44 TeV.

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Proton emission in ultraperipheral Pb-Pb collisions at $\sqrt{\textit{s}_{\mathrm{\textbf{NN}}}}=5.02$ TeV

The ALICE collaboration Acharya, Shreyasi ; Agarwal, Apar ; Aglieri Rinella, Gianluca ; et al.
Phys.Rev.C 111 (2025) 054906, 2025.
Inspire Record 2846998 DOI 10.17182/hepdata.157600

The first measurements of proton emission accompanied by neutron emission in the electromagnetic dissociation (EMD) of $^{208}$Pb nuclei in the ALICE experiment at the LHC are presented. The EMD protons and neutrons emitted at very forward rapidities are detected by the proton and neutron Zero Degree Calorimeters of the ALICE experiment. The emission cross sections of zero, one, two, and three protons accompanied by at least one neutron were measured in ultraperipheral $^{208}$Pb--$^{208}$Pb collisions at a center-of-mass energy per nucleon pair $\sqrt{s_{\rm NN}}=5.02$ TeV. The 0p and 3p cross sections are described by the RELDIS model within their measurement uncertainties, while the 1p and 2p cross sections are underestimated by the model by 17-25%. According to this model, these 0p, 1p, 2p, and 3p cross sections are associated, respectively, with the production of various isotopes of Pb, Tl, Hg, and Au in the EMD of $^{208}$Pb. The cross sections of the emission of a single proton accompanied by the emission of one, two, or three neutrons in EMD were also measured. The data are significantly overestimated by the RELDIS model, which predicts that the (1p,1n), (1p,2n), and (1p,3n) cross sections are very similar to the cross sections for the production of the thallium isotopes $^{206,205,204}$Tl.

2 data tables

Measured cross sections of the emission of a given number of protons k accompanied by at least one neutron i in UPC of Pb nuclei.

Measured cross sections of the emission of a given number of neutrons i accompanied by a single proton in UPC of Pb nuclei.


Measurements of differential two-particle number and transverse momentum correlation functions in pp collisions at $\sqrt{\textit{s}}$ = 13 TeV

The ALICE collaboration Acharya, Shreyasi ; Agarwal, Apar ; Aglieri Rinella, Gianluca ; et al.
Eur.Phys.J.C 85 (2025) 866, 2025.
Inspire Record 2847021 DOI 10.17182/hepdata.159895

Differential two-particle normalized cumulants ($R_2$) and transverse momentum correlations ($P_2$) are measured as a function of the relative pseudorapidity and azimuthal angle difference $( \Delta \eta, \Delta \varphi )$ of charged particle pairs in minimum bias pp collisions at $\sqrt{\textit{s}}$ = 13 TeV. The measurements use charged hadrons in the pseudorapidity region of $|\eta| < 0.8$ and the transverse momentum range 0.2 $< \textit{p}_{\mathrm T} < $ 2.0 $\mathrm{GeV}/\textit{c}$ in order to focus on soft multiparticle interactions and to complement prior measurements of these correlation functions in p-Pb and Pb-Pb collisions. The correlation functions are reported for both unlike-sign and like-sign pairs and their charge-independent and charge-dependent combinations. Both the $R_2$ and $P_2$ measured in pp collisions exhibit features qualitatively similar to those observed in p-Pb and Pb-Pb collisions. The $\Delta\eta$ and $\Delta\varphi$ root mean square widths of the near-side peak of the correlation functions are evaluated and compared with those observed in p-Pb and Pb-Pb collisions and show smooth evolution with the multiplicity of charged particles produced in the collision. The comparison of the measured correlation functions with predictions from PYTHIA8 shows that this model qualitatively captures their basic structure and characteristics but feature important differences. In addition, the $R_2^{\rm CD}$ is used to determine the charge balance function of hadrons produced within the detector acceptance of the measurements. The integral of the balance function is found to be compatible with those reported by a previous measurement in Pb-Pb collisions. These results, which are sensitive to the interplay between the underlying event and mini-jets in pp collisions, establish a baseline for heavy-ion collisions.

21 data tables

Correlation functions $R_2^{\rm US}$ of charged hadrons measured in minimum bias pp collisions at $\sqrt{s}=13\;\text{TeV}$. Charged hadrons are selected in the range $0.2 < p_{\rm T} < 2.0$ GeV/$c$ and with pseudorapidity $|\eta| < 0.8$.

Correlation functions $R_2^{\rm LS}$ of charged hadrons measured in minimum bias pp collisions at $\sqrt{s}=13\;\text{TeV}$. Charged hadrons are selected in the range $0.2 < p_{\rm T} < 2.0$ GeV/$c$ and with pseudorapidity $|\eta| < 0.8$.

Correlation functions $P_2^{\rm US}$ of charged hadrons measured in minimum bias pp collisions at $\sqrt{s}=13\;\text{TeV}$. Charged hadrons are selected in the range $0.2 < p_{\rm T} < 2.0$ GeV/$c$ and with pseudorapidity $|\eta| < 0.8$.

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Medium-induced modification of groomed and ungroomed jet mass and angularities in Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV

The ALICE collaboration Acharya, Shreyasi ; Agarwal, Apar ; Aglieri Rinella, Gianluca ; et al.
Phys.Lett.B 864 (2025) 139409, 2025.
Inspire Record 2845788 DOI 10.17182/hepdata.157864

The ALICE Collaboration presents a new suite of jet substructure measurements in Pb-Pb and pp collisions at a center-of-mass energy per nucleon pair $\sqrt{s}_{\rm NN} = 5.02$ TeV. These measurements provide access to the internal structure of jets via the momentum and angle of their constituents, probing how the quark--gluon plasma modifies jets, an effect known as jet quenching. Jet grooming additionally removes soft wide-angle radiation to enhance perturbative accuracy and reduce experimental uncertainties. We report the groomed and ungroomed jet mass $m_{\rm jet}$ and jet angularities $\lambda_\alpha^\kappa$ using $\kappa=1$ and $\alpha>0$. Charged-particle jets are reconstructed at midrapidity using the anti-$k_\mathrm{T}$ algorithm with resolution parameter $R = 0.2$. A narrowing of the jet mass and angularity distributions in Pb-Pb collisions with respect to pp is observed and is enhanced for groomed results, confirming modification of the jet core. By using consistent jet definitions and kinematic cuts between the mass and angularities for the first time, previous inconsistencies in the interpretation of quenching measurements are resolved, rectifying a hurdle for understanding how jet quenching arises from first principles and highlighting the importance of a well-controlled baseline. These results are compared with a variety of theoretical models of jet quenching, providing constraints on jet energy-loss mechanisms in the quark--gluon plasma.

46 data tables

Jet angularity $\lambda_{\alpha}$ for $\alpha = 1$. $40<p_{\mathrm{T}}^{\mathrm{ch jet}}<60$. For the "trkeff" and "generator" systematic uncertainty sources, the signed systematic uncertainty breakdowns ($\pm$ vs. $\mp$), denote correlation across bins (both within this table, and across tables). For the remaining sources ("unfolding", "random_mass") no correlation information is specified ($\pm$ is always used).

Jet angularity $\lambda_{\alpha}$ for $\alpha = 1.5$. $40<p_{\mathrm{T}}^{\mathrm{ch jet}}<60$ GeV/$c$. For the "trkeff" and "generator" systematic uncertainty sources, the signed systematic uncertainty breakdowns ($\pm$ vs. $\mp$), denote correlation across bins (both within this table, and across tables). For the remaining sources ("unfolding", "random_mass") no correlation information is specified ($\pm$ is always used).

Jet angularity $\lambda_{\alpha}$ for $\alpha = 2$. $40<p_{\mathrm{T}}^{\mathrm{ch jet}}<60$ GeV/$c$. For the "trkeff" and "generator" systematic uncertainty sources, the signed systematic uncertainty breakdowns ($\pm$ vs. $\mp$), denote correlation across bins (both within this table, and across tables). For the remaining sources ("unfolding", "random_mass") no correlation information is specified ($\pm$ is always used).

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First measurement of A = 4 (anti)hypernuclei at the LHC

The ALICE collaboration Acharya, Shreyasi ; Agarwal, Apar ; Aglieri Rinella, Gianluca ; et al.
CERN-EP-2024-265, 2024.
Inspire Record 2842103 DOI 10.17182/hepdata.158317

In this Letter, the first evidence of the ${}^4_{\bar{\Lambda}}\overline{\mathrm{He}}$ antihypernucleus is presented, along with the first measurement at the LHC of the production of (anti)hypernuclei with mass number $A=4$, specifically (anti)${}^4_{\Lambda}\mathrm{H}$ and (anti)${}^4_{\Lambda}\mathrm{He}$. In addition, the antiparticle-to-particle ratios for both hypernuclei (${}^4_{\bar{\Lambda}}\overline{\mathrm{H}}$ / ${}^4_{\Lambda}\mathrm{H}$~and ${}^4_{\bar{\Lambda}}\overline{\mathrm{He}}$ / ${}^4_{\Lambda}\mathrm{He}$) are shown, which are sensitive to the baryochemical potential of the strongly-interacting matter created in heavy-ion collisions. The results are obtained from a data sample of central Pb--Pb collisions, collected during the 2018 LHC data-taking at a center-of-mass energy per nucleon pair of $\sqrt{s_{\mathrm{NN}}} = $ 5.02 TeV. The yields measured for the average of the charge-conjugated states are found to be $[0.78 \; \pm \; 0.19 \; \mathrm{(stat.)} \; \pm \; 0.17 \; \mathrm{(syst.)}] \times 10^{-6}$ for the (anti)${}^4_{\Lambda}\mathrm{H}$ and $[1.08 \; \pm \; 0.34 \; \mathrm{(stat.)} \; \pm \; 0.20 \; \mathrm{(syst.)}] \times 10^{-6}$ for the (anti)${}^4_{\Lambda}\mathrm{He}$, and the measured antiparticle-to-particle ratios are in agreement with unity. The presence of (anti)${}^4_{\Lambda}\mathrm{H}$ and (anti)${}^4_{\Lambda}\mathrm{He}$ excited states is expected to strongly enhance the production yield of these hypernuclei. The yield values exhibit a combined deviation of 3.3$\sigma$ from the theoretical ground-state-only expectation, while the inclusion of the excited states in the calculations leads to an agreement within 0.6$\sigma$ with the present measurements. Additionally, the measured (anti)${}^4_{\Lambda}\mathrm{H}$ and (anti)${}^4_{\Lambda}\mathrm{He}$ masses are compatible with the world-average values within the uncertainties.

3 data tables

average pT-integrated yield of particle and antiparticle of both analyzed (anti)hypernuclei in Pb-Pb collisions in 0-10% V0M centrality class

mass measurement of both analyzed (anti)hypernuclei in Pb-Pb collisions in 0-10% V0M centrality class

antiparticle-to-particle ratio of the analyzed (anti)hypernuclei in Pb-Pb collisions in 0-10% V0M centrality class


Multimuons in cosmic-ray events as seen in ALICE at the LHC

The ALICE collaboration Acharya, Shreyasi ; Agarwal, Apar ; Aglieri Rinella, Gianluca ; et al.
JCAP 04 (2025) 009, 2025.
Inspire Record 2842099 DOI 10.17182/hepdata.158063

ALICE is a large experiment at the CERN Large Hadron Collider. Located 52 meters underground, its detectors are suitable to measure muons produced by cosmic-ray interactions in the atmosphere. In this paper, the studies of the cosmic muons registered by ALICE during Run 2 (2015--2018) are described. The analysis is limited to multimuon events defined as events with more than four detected muons ($N_\mu>4$) and in the zenith angle range $0^{\circ}<\theta<50^{\circ}$. The results are compared with Monte Carlo simulations using three of the main hadronic interaction models describing the air shower development in the atmosphere: QGSJET-II-04, EPOS-LHC, and SIBYLL 2.3d. The interval of the primary cosmic-ray energy involved in the measured muon multiplicity distribution is about $ 4 \times 10^{15}<E_\mathrm{prim}< 6 \times 10^{16}$~eV. In this interval none of the three models is able to describe precisely the trend of the composition of cosmic rays as the energy increases. However, QGSJET-II-04 is found to be the only model capable of reproducing reasonably well the muon multiplicity distribution, assuming a heavy composition of the primary cosmic rays over the whole energy range, while SIBYLL 2.3d and EPOS-LHC underpredict the number of muons in a large interval of multiplicity by more than $20\%$ and $30\%$, respectively. The rate of high muon multiplicity events ($N_\mu>100$) obtained with QGSJET-II-04 and SIBYLL 2.3d is compatible with the data, while EPOS-LHC produces a significantly lower rate ($55\%$ of the measured rate). For both QGSJET-II-04 and SIBYLL 2.3d, the rate is close to the data when the composition is assumed to be dominated by heavy elements, an outcome compatible with the average energy $E_\mathrm{prim} \sim 10^{17}$ eV of these events. This result places significant constraints on more exotic production mechanisms.

15 data tables

Muon multiplicity distribution measured with the ALICE apparatus and obtained for the whole data sample of Run 2 corresponding to a live time of 62.5 days. The data points are grouped in multiplicity intervals with a width of five units ($N_\mu=5-9,~N_\mu=10-14,~...$), and are located at the center of each interval ($N_\mu=7,~N_\mu=12,~...$). The vertical error bars represent the statistical uncertainties.

Muon multiplicity distribution measured with the ALICE apparatus and obtained for the whole data sample of Run 2 corresponding to a live time of 62.5 days. The data are the same as Fig. 3 but each bin corresponds to a single muon multiplicity ($N_\mu=1,2,3,~...$); the distribution starts at $N_\mu=5$. The vertical error bars represent the statistical uncertainties.

Measured muon multiplicity distribution compared with simulations from CORSIKA Monte Carlo generator using QGSJET-II-04 (top), SIBYLL 2.3 (middle), and EPOS-LHC (bottom) as hadronic interaction models for proton and iron primary cosmic rays. Iron points are slightly shifted to the right to avoid overlapping with the data points. The total uncertainties in the MC simulations are given by the vertical bars, while the boxes give the systematic uncertainties of the data and the vertical bars the statistical ones.

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Version 2
Dark Matter Search Results from 4.2 Tonne-Years of Exposure of the LUX-ZEPLIN (LZ) Experiment

The LZ collaboration Aalbers, J. ; Akerib, D.S. ; Al Musalhi, A.K. ; et al.
Phys.Rev.Lett. 135 (2025) 011802, 2025.
Inspire Record 2841863 DOI 10.17182/hepdata.155182

We report results of a search for nuclear recoils induced by weakly interacting massive particle (WIMP) dark matter using the LUX-ZEPLIN (LZ) two-phase xenon time projection chamber. This analysis uses a total exposure of $4.2\pm0.1$ tonne-years from 280 live days of LZ operation, of which $3.3\pm0.1$ tonne-years and 220 live days are new. A technique to actively tag background electronic recoils from $^{214}$Pb $β$ decays is featured for the first time. Enhanced electron-ion recombination is observed in two-neutrino double electron capture decays of $^{124}$Xe, representing a noteworthy new background. After removal of artificial signal-like events injected into the data set to mitigate analyzer bias, we find no evidence for an excess over expected backgrounds. World-leading constraints are placed on spin-independent (SI) and spin-dependent WIMP-nucleon cross sections for masses $\geq$9 GeV/$c^2$. The strongest SI exclusion set is $2.2\times10^{-48}$ cm$^{2}$ at the 90% confidence level and the best SI median sensitivity achieved is $5.1\times10^{-48}$ cm$^{2}$, both for a mass of 40 GeV/$c^2$.

10 data tables

90% CL WIMP SI cross sections, including sensitivities

90% CL WIMP SI cross sections, including sensitivities

90% CL WIMP SDn cross sections, including sensitivities and nuclear structure uncertainties

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Measurements at forward rapidity of elliptic flow of charged hadrons and open-heavy-flavor muons in Au$+$Au collisions at $\sqrt{s_{_{NN}}}=200$ GeV

The PHENIX collaboration Abdulameer, N.J. ; Acharya, U. ; Adare, A. ; et al.
2024.
Inspire Record 2830400 DOI 10.17182/hepdata.159542

We present the first forward-rapidity measurements of elliptic anisotropy of open-heavy-flavor muons at the BNL Relativistic Heavy Ion Collider. The measurements are based on data samples of Au$+$Au collisions at $\sqrt{s_{_{NN}}}=200$ GeV collected by the PHENIX experiment in 2014 and 2016 with integrated luminosity of 14.5~nb$^{-1}$. The measurements are performed in the pseudorapidity range $1.2<|\eta|<2$ and cover transverse momenta $1<p_T<4$~GeV/$c$. The elliptic flow of charged hadrons as a function of transverse momentum is also measured in the same kinematic range. We observe significant elliptic flow for both charged hadrons and heavy-flavor muons. The results show clear mass ordering of elliptic flow of light- and heavy-flavor particles. The magnitude of the measured $v_2$ is comparable to that in the midrapidity region. This indicates that there is no strong longitudinal dependence in the quark-gluon-plasma evolution between midrapidity and the rapidity range of this measurement at $\sqrt{s_{_{NN}}}=200$~GeV.

9 data tables

Lastgap $v_2$

Hadron-Muon Ratio at $1.2 < |\eta| < 2.0$

HF Fraction at $1.2 < |\eta| < 2.0$ Top Tuned Slim

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