Multiplicity dependence of J/$\psi$ production at midrapidity in pp collisions at $\sqrt{s}$ = 13 TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adler, Alexander ; et al.
Phys.Lett. B (2020) 135758, 2020.
Inspire Record 1797445 DOI 10.17182/hepdata.96306

Measurements of the inclusive J/$\psi$ yield as a function of charged-particle pseudorapidity density $\rm{d}N_\rm{ch}/\rm{d}\eta$ in pp collisions at $\sqrt{s}$ = 13 TeV with ALICE at the LHC are reported. The J/$\psi$ meson yield is measured at midrapidity ($|y|<0.9$) in the dielectron channel, for events selected based on the charged-particle multiplicity at midrapidity ($|\eta|<1$) and at forward rapidity ($-3.7<\eta<-1.7$ and $2.8<\eta<5.1$); both observables are normalized to their corresponding averages in minimum bias events. The increase of the normalized J/$\psi$ yield with normalized $\rm{d}N/\rm{d}\eta$ is significantly stronger than linear and dependent on the transverse momentum. The data are compared to theoretical predictions, which describe the observed trends well, albeit not always quantitatively.

6 data tables

$N_{J/psi}/<N_{J/\psi}> / N_{ch}/<N_{ch}>$, $|y^{J/\psi}|<0.9$, $p_{T}^{J/\psi}$ integrated, event selection SPD

$N_{J/psi}/<N_{J/\psi}> / N_{ch}/<N_{ch}>$, $|y^{J/\psi}|<0.9$, $p_{T}^{J/\psi}$ integrated, event selection V0

$N_{J/psi}/<N_{J/\psi}> / N_{ch}/<N_{ch}>$, $|y^{J/\psi}|<0.9$, $p_{T}^{J/\psi}$ 0-4 and 4-8 GeV/c, event selection SPD

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Measurement of the central exclusive production of charged particle pairs in proton-proton collisions at $\sqrt{s} = 200$ GeV with the STAR detector at RHIC

The STAR collaboration Adam, J. ; Adamczyk, L. ; Adams, J.R. ; et al.
JHEP 07 (2020) 178, 2020.
Inspire Record 1792394 DOI 10.17182/hepdata.94264

We report on the measurement of the Central Exclusive Production of charged particle pairs $h^{+}h^{-}$ ($h = \pi, K, p$) with the STAR detector at RHIC in proton-proton collisions at $\sqrt{s} = 200$ GeV. The charged particle pairs produced in the reaction $pp\to p^\prime+h^{+}h^{-}+p^\prime$ are reconstructed from the tracks in the central detector, while the forward-scattered protons are measured in the Roman Pot system. Differential cross sections are measured in the fiducial region, which roughly corresponds to the square of the four-momentum transfers at the proton vertices in the range $0.04~\mbox{GeV}^2 < -t_1 , -t_2 < 0.2~\mbox{GeV}^2$, invariant masses of the charged particle pairs up to a few GeV and pseudorapidities of the centrally-produced hadrons in the range $|\eta|<0.7$. The measured cross sections are compared to phenomenological predictions based on the Double Pomeron Exchange (DPE) model. Structures observed in the mass spectra of $\pi^{+}\pi^{-}$ and $K^{+}K^{-}$ pairs are consistent with the DPE model, while angular distributions of pions suggest a dominant spin-0 contribution to $\pi^{+}\pi^{-}$ production. The fiducial $\pi^+\pi^-$ cross section is extrapolated to the Lorentz-invariant region, which allows decomposition of the invariant mass spectrum into continuum and resonant contributions. The extrapolated cross section is well described by the continuum production and at least three resonances, the $f_0(980)$, $f_2(1270)$ and $f_0(1500)$, with a possible small contribution from the $f_0(1370)$. Fits to the extrapolated differential cross section as a function of $t_1$ and $t_2$ enable extraction of the exponential slope parameters in several bins of the invariant mass of $\pi^+\pi^-$ pairs. These parameters are sensitive to the size of the interaction region.

47 data tables

Differential fiducial cross section for CEP of $\pi^+\pi^-$ pairs as a function of the invariant mass of the pair. Systematic uncertainties assigned to data points are strongly correlated between bins and should be treated as allowed collective variation of all data points. There are two components of the total systematic uncertainty. The systematic uncertainty related to the experimental tools and analysis method is labeled "syst. (experimental)". The systematic uncertainty related to the integrated luminosity (fully correlated between all data points) is labeled "syst. (luminosity)". Fiducial region definition: * central state $\pi^+$, $\pi^-$ - $p_{\mathrm{T}} > 0.2~\mathrm{GeV}$ - $|\eta| < 0.7$ * intact forward-scattered beam protons $p'$ - $p_x > -0.2~\mathrm{GeV}$ - $0.2~\mathrm{GeV} < |p_{y}| < 0.4~\mathrm{GeV}$ - $(p_x+0.3~\mathrm{GeV})^2 + p_y^2 < 0.25~\mathrm{GeV}^2$

Differential fiducial cross section for CEP of $K^+K^-$ pairs as a function of the invariant mass of the pair. Systematic uncertainties assigned to data points are strongly correlated between bins and should be treated as allowed collective variation of all data points. There are two components of the total systematic uncertainty. The systematic uncertainty related to the experimental tools and analysis method is labeled "syst. (experimental)". The systematic uncertainty related to the integrated luminosity (fully correlated between all data points) is labeled "syst. (luminosity)". Fiducial region definition: * central state $K^+$, $K^-$ - $p_{\mathrm{T}} > 0.3~\mathrm{GeV}$ - $min(p_{\mathrm{T}}(K^+), p_{\mathrm{T}}(K^-)) < 0.7~\mathrm{GeV}$ - $|\eta| < 0.7$ * intact forward-scattered beam protons $p'$ - $p_x > -0.2~\mathrm{GeV}$ - $0.2~\mathrm{GeV} < |p_{y}| < 0.4~\mathrm{GeV}$ - $(p_x+0.3~\mathrm{GeV})^2 + p_y^2 < 0.25~\mathrm{GeV}^2$

Differential fiducial cross section for CEP of $p\bar{p}$ pairs as a function of the invariant mass of the pair. Systematic uncertainties assigned to data points are strongly correlated between bins and should be treated as allowed collective variation of all data points. There are two components of the total systematic uncertainty. The systematic uncertainty related to the experimental tools and analysis method is labeled "syst. (experimental)". The systematic uncertainty related to the integrated luminosity (fully correlated between all data points) is labeled "syst. (luminosity)". Fiducial region definition: * central state $p$, $\bar{p}$ - $p_{\mathrm{T}} > 0.4~\mathrm{GeV}$ - $min(p_{\mathrm{T}}(p), p_{\mathrm{T}}(\bar{p})) < 1.1~\mathrm{GeV}$ - $|\eta| < 0.7$ * intact forward-scattered beam protons $p'$ - $p_x > -0.2~\mathrm{GeV}$ - $0.2~\mathrm{GeV} < |p_{y}| < 0.4~\mathrm{GeV}$ - $(p_x+0.3~\mathrm{GeV})^2 + p_y^2 < 0.25~\mathrm{GeV}^2$

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Results on Total and Elastic Cross Sections in Proton-Proton Collisions at $\sqrt{s} = 200$ GeV

The STAR collaboration Adam, Jaroslav ; Adamczyk, Leszek ; Adams, Joseph ; et al.
Phys.Lett.B 808 (2020) 135663, 2020.
Inspire Record 1791591 DOI 10.17182/hepdata.94263

We report results on the total and elastic cross sections in proton-proton collisions at $\sqrt{s}=200$ GeV obtained with the Roman Pot setup of the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). The elastic differential cross section was measured in the squared four-momentum transfer range $0.045 \leq -t \leq 0.135$ GeV$^2$. The value of the exponential slope parameter $B$ of the elastic differential cross section $d\sigma/dt \sim e^{-Bt}$ in the measured $-t$ range was found to be $B = 14.32 \pm 0.09 (stat.)^{\scriptstyle +0.13}_{\scriptstyle -0.28} (syst.)$ GeV$^{-2}$. The total cross section $\sigma_{tot}$, obtained from extrapolation of the $d\sigma/dt$ to the optical point at $-t = 0$, is $\sigma_{tot} = 54.67 \pm 0.21 (stat.) ^{\scriptstyle +1.28}_{\scriptstyle -1.38} (syst.)$ mb. We also present the values of the elastic cross section $\sigma_{el} = 10.85 \pm 0.03 (stat.) ^{\scriptstyle +0.49}_{\scriptstyle -0.41}(syst.)$ mb, the elastic cross section integrated within the STAR $t$-range $\sigma^{det}_{el} = 4.05 \pm 0.01 (stat.) ^{\scriptstyle+0.18}_{\scriptstyle -0.17}(syst.)$ mb, and the inelastic cross section $\sigma_{inel} = 43.82 \pm 0.21 (stat.) ^{\scriptstyle +1.37}_{\scriptstyle -1.44} (syst.)$ mb. The results are compared with the world data.

3 data tables

The proton-proton elastic differential cross-section $d\sigma_{el}/dt$ in the t-range 0.045<|t|<0.135 $GeV^{2}$ at sqrt(s) = 200 GeV.

The B-slope of the exponential fit A*exp(-B*|t|) to the single differential proton-proton elastic cross-section in the t-range 0.045<|t|<0.135 GeV**2 at sqrt(s) = 200 GeV.

The total, elastic and inelastic cross-sections for proton-proton scattering at sqrt(s)=200 GeV, the elastic cross-section measured in the t-range 0.045<|t|<0.135 GeV^2 and the value of the differential cross-section extrapolated to |t| = 0.


Measurement of nuclear effects on $\psi\rm{(2S)}$ production in p-Pb collisions at $\sqrt{\textit{s}_{\rm NN}} = 8.16$ TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adler, Alexander ; et al.
JHEP 07 (2020) 237, 2020.
Inspire Record 1785315 DOI 10.17182/hepdata.96029

Inclusive $\psi$(2S) production is measured in p-Pb collisions at the centre-of-mass energy per nucleon-nucleon pair $\sqrt{s_{\rm{NN}}}=8.16$ TeV, using the ALICE detector at the CERN LHC. The production of $\psi$(2S) is studied at forward ($2.03 < y_{\rm cms} < 3.53$) and backward ($-4.46 < y_{\rm cms} < -2.96$) centre-of-mass rapidity and for transverse momentum $p_{\rm{T}}$ $<$ 12 GeV/$c$ via the decay to muon pairs. In this paper, we report the integrated as well as the $y_{\rm cms}$- and $p_{\rm T}$-differential inclusive production cross sections. Nuclear effects on $\psi$(2S) production are studied via the determination of the nuclear modification factor that shows a strong suppression at both forward and backward centre-of-mass rapidities. Comparisons with corresponding results for inclusive J/$\psi$ show a similar suppression for the two states at forward rapidity (p-going direction), but a stronger suppression for $\psi$(2S) at backward rapidity (Pb-going direction). As a function of $p_{\rm T}$, no clear dependence of the nuclear modification factor is found. The relative size of nuclear effects on $\psi$(2S) production compared to J/$\psi$ is also studied via the double ratio of production cross sections $[\sigma_{\psi(2S)}/\sigma_{\rm{J/}\psi}]_{\rm pPb}/[\sigma_{\psi(2S)}/\sigma_{\rm{J/}\psi}]_{\rm pp}$ between p-Pb and pp collisions. The results are compared with theoretical models that include various effects related to the initial and final state of the collision system and also with previous measurements at $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV.

14 data tables

Inclusive $\psi(2{\rm S})$ differential cross section times branching ratio as a function of $y_{\rm cms}$, in p--Pb collisions at $\sqrt{s_{\rm NN}}$ = 8.16 TeV. The first uncertainty is statistical, the second is the uncorrelated systematic, while the third one is a correlated systematic uncertainty.

Inclusive $\psi(2{\rm S})$ differential cross section times branching ratio as a function of $p_{\rm T}$, at forward rapidity at $\sqrt{s_{\rm NN}}$ = 8.16 TeV .The first uncertainty is statistical, the second is the uncorrelated systematic, while the third one is a correlated systematic uncertainty.

Inclusive $\psi(2{\rm S})$ differential cross section times branching ratio as a function of $p_{\rm T}$, at backward rapidity at $\sqrt{s_{\rm NN}}$ = 8.16 TeV .The first uncertainty is statistical, the second is the uncorrelated systematic, while the third one is a correlated systematic uncertainty.

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Coherent photoproduction of $\rho^{0}$ vector mesons in ultra-peripheral Pb-Pb collisions at $ \sqrt{{\mathrm{s}}_{\mathrm{NN}}} $ = 5.02 TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adler, Alexander ; et al.
JHEP 06 (2020) 035, 2020.
Inspire Record 1782227 DOI 10.17182/hepdata.95218

Cross sections for the coherent photoproduction of $\rho^{0}$ vector mesons in ultra-peripheral Pb-Pb collisions at $ \sqrt{s_{\mathrm{NN}}}= 5.02$ TeV are reported. The measurements, which rely on the $\pi^+\pi^-$ decay channel, are presented in three regions of rapidity covering the range $|y|<0.8$. For each rapidity interval, cross sections are shown for different nuclear-breakup classes defined according to the presence of neutrons measured in the zero-degree calorimeters. The results are compared with predictions based on different models of nuclear shadowing. Finally, the observation of a coherently produced resonance-like structure with a mass around 1.7 GeV/$c^2$ and a width of about 140 MeV/$c^2$ is reported and compared with similar observations from other experiments.

1 data table

Differential cross section as a function of rapidity for coherent RHO0 photoproduction in ultra-peripheral Pb-Pb collisions at ALICE.


Linear and non-linear flow modes of charged hadrons in Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adler, Alexander ; et al.
JHEP 05 (2020) 085, 2020.
Inspire Record 1778342 DOI 10.17182/hepdata.94869

Anisotropic flow coefficients, $v_n$, non-linear flow mode coefficients, $\chi_{n,mk}$, and correlations among different symmetry planes, $\rho_{n,mk}$ are measured in Pb-Pb collisions at $\sqrt{s_\rm{NN}}=5.02$ TeV. Results obtained with multi-particle correlations are reported for the transverse momentum interval $0.2<p_\rm{T}<5.0$ GeV/$c$ within the pseudorapidity interval $0.4<|\eta|<0.8$ as a function of collision centrality. The $v_n$ coefficients and $\chi_{n,mk}$ and $\rho_{n,mk}$ are presented up to the ninth and seventh harmonic order, respectively. Calculations suggest that the correlations measured in different symmetry planes and the non-linear flow mode coefficients are dependent on the shear and bulk viscosity to entropy ratios of the medium created in heavy-ion collisions. The comparison between these measurements and those at lower energies and calculations from hydrodynamic models places strong constraints on the initial conditions and transport properties of the system.

23 data tables

Centrality dependence of flow harmonics from $v_2$ to $v_9$.

Centrality dependence of flow harmonics from $v_2$ to $v_9$.

Centrality dependence of flow harmonics from $v_2$ to $v_9$.

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Underlying event measurements in $p+p$ collisions at $\sqrt s=$ 200 GeV at RHIC

The STAR collaboration Adam, Jaroslav ; Adamczyk, Leszek ; Adams, Joseph ; et al.
Phys.Rev.D 101 (2020) 052004, 2020.
Inspire Record 1771348 DOI 10.17182/hepdata.95537

Particle production sensitive to non-factorizable and non-perturbative processes that contribute to the underlying event associated with a high transverse momentum ($p_{T}$) jet in proton+proton collisions at $\sqrt{s}$=200 GeV is studied with the STAR detector. Each event is divided into three regions based on the azimuthal angle with respect to the highest-$p_{T}$ jet direction: in the leading jet direction ("Toward"), opposite to the leading jet ("Away"), and perpendicular to the leading jet ("Transverse"). In the Transverse region, the average charged particle density is found to be between 0.4 and 0.6 and the mean transverse momentum, $\langle p_{T}\rangle$, between 0.5-0.7 GeV/$c$ for particles with $p_{T}$$>$0.2 GeV/$c$ at mid-pseudorapidity ($|\eta|$$<$1) and jet $p_{T}$$>$15 GeV/$c$. Both average particle density and $\langle p_{T}\rangle$ depend weakly on the leading jet $p_{T}$. Closer inspection of the Transverse region hints that contributions to the underlying event from initial- and final-state radiation are significantly smaller in these collisions than at the higher energies, up to 13 TeV, recorded at the LHC. Underlying event measurements associated with a high-$p_{T}$ jet will contribute to our understanding of QCD processes at hard and soft scales at RHIC energies, as well as provide constraints to modeling of underlying event dynamics.

6 data tables

Average charged particle multiplicity densities for Toward, Away, and Transverse regions as functions of the leading jet pT, with charged particle pT>0.2 GeV/c. The wide curves are PYTHIA 6 (STAR). The middle width curves are default PYTHIA 6 Perugia 2012 tune. The thin curves are PYTHIA 8 Monash 2013 tune. The solid curves are the Toward region. The sparse dashed curves are the Away region. The dense dashed curves are the Transverse region.

Transverse region average charged particle densities for pT>0.2 GeV/c (open symbols) and pT>0.5 GeV/c (filled symbols). Simulations are also shown as curves. The wide curves are PYTHIA 6 (STAR). The middle width curves are default PYTHIA 6 Perugia 2012 tune. The thin curves are PYTHIA 8 Monash 2013 tune.

Charged particle <pT> for Toward, Away, and Transverse regions as functions of the leading jet pT, with charged particle pT>0.2 GeV/c. Simulations are also shown as curves. The wide curves are PYTHIA 6 (STAR). The middle width curves are default PYTHIA 6 Perugia 2012 tune. The thin curves are PYTHIA 8 Monash 2013 tune. Note the three curves overlap for the Transverse region calculations.

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Measurement of D$^0$-meson + hadron two-dimensional angular correlations in Au+Au collisions at $\sqrt{s_{\rm NN}}$ = 200 GeV

The STAR collaboration Adam, J. ; Adamczyk, Leszek ; Adams, Joseph ; et al.
Phys.Rev.C 102 (2020) 014905, 2020.
Inspire Record 1767419 DOI 10.17182/hepdata.95209

Open heavy flavor hadrons provide unique probes of the medium produced in ultra-relativistic heavy-ion collisions. Due to their increased mass relative to light-flavor hadrons, long lifetime, and early production in hard-scattering interactions, they provide access to the full evolution of the partonic medium formed in heavy-ion collisions. This paper reports two-dimensional (2D) angular correlations between neutral $D$-mesons and unidentified charged particles produced in minimum-bias Au+Au collisions at $\sqrt{s_{\rm NN}}$ = 200 GeV. $D^0$ and $\bar{D}^0$ mesons are reconstructed via their weak decay to $K^{\mp} \pi^{\pm}$ using the Heavy Flavor Tracker (HFT) in the Solenoidal Tracker at RHIC (STAR) experiment. Correlations on relative pseudorapidity and azimuth $(\Delta\eta,\Delta\phi)$ are presented for peripheral, mid-central and central collisions with $D^0$ transverse momentum from 2 to 10 GeV/$c$. Attention is focused on the 2D peaked correlation structure near the triggered $D^0$-meson, the {\em near-side} (NS) peak, which serves as a proxy for a charm-quark containing jet. The correlated NS yield of charged particles per $D^0$-meson and the 2D widths of the NS peak increase significantly from peripheral to central collisions. These results are compared with similar correlations using unidentified charged particles, consisting primarily of light-flavor hadrons, at similar trigger particle momenta. Similar per-trigger yields and widths of the NS correlation peak are observed. The present results provide additional evidence that $D^0$-mesons undergo significant interactions with the medium formed in heavy-ion collision and show, for the first time, significant centrality evolution of the NS 2D peak in the correlations of particles associated with a heavy-flavor hadron produced in these collisions.

4 data tables

Amplitude of the quadrupole term, A_Q, extracted from the fitting of the correlations, presented as a function of centrality.

Width of the near-side gaussian on the delPhi coordinate extracted from the fitting of the correlations, presented as a function of centrality.

Width of the near-side gaussian on the delEta coordinate extracted from the fitting of the correlations, presented as a function of centrality.

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Investigation of the p-$\Sigma^{0}$ interaction via femtoscopy in pp collisions

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adler, Alexander ; et al.
Phys.Lett.B 805 (2020) 135419, 2020.
Inspire Record 1762369 DOI 10.17182/hepdata.94238

This Letter presents the first direct investigation of the p-$\Sigma^{0}$ interaction, using the femtoscopy technique in high-multiplicity pp collisions at $\sqrt{s}$ = 13 TeV measured by the ALICE detector. The $\Sigma^{0}$ is reconstructed via the decay channel to $\Lambda \gamma$, and the subsequent decay of $\Lambda$ to p$\pi^-$. The photon is detected via the conversion in material to e$^{+}$e$^{-}$ pairs exploiting the unique capability of the ALICE detector to measure electrons at low transverse momenta. The measured p-$\Sigma^{0}$ correlation indicates a shallow strong interaction. The comparison of the data to several theoretical predictions obtained employing the $Correlation~Analysis~Tool~using~the~Schr\"odinger~Equation$ (CATS) and the Lednick\'y-Lyuboshits approach shows that the current experimental precision does not yet allow to discriminate between different models, as it is the case for the available scattering and hypernuclei data. Nevertheless, the p-$\Sigma^{0}$ correlation function is found to be sensitive to the strong interaction, and driven by the interplay of the different spin and isospin channels. This pioneering study demonstrates the feasibility of a femtoscopic measurement in the p-$\Sigma^{0}$ channel and with the expected larger data samples in LHC Run 3 and Run 4, the p-$\Sigma^{0}$ interaction will be constrained with high precision.

2 data tables

Measured p$-$p $\oplus$ $\overline{\mathrm{p}}-\overline{\mathrm{p}}$ correlation function.

Measured correlation function of p$-\Sigma^{0}$p $\oplus$ $\overline{\mathrm{p}}-\overline{\Sigma^{0}}$


Evidence of rescattering effect in Pb-Pb collisions at the LHC through production of $\rm{K}^{*}(892)^{0}$ and $\phi(1020)$ mesons

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adler, Alexander ; et al.
Phys.Lett.B 802 (2020) 135225, 2020.
Inspire Record 1762368 DOI 10.17182/hepdata.93150

Measurements of $\rm{K}^{*}(892)^{0}$ and $\phi(1020)$ resonance production in Pb-Pb and pp collisions at $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV with the ALICE detector at the Large Hadron Collider are reported. The resonances are measured at midrapidity ($|y|$ $<$ 0.5) via their hadronic decay channels and the transverse momentum ($p_{\rm{T}}$) distributions are obtained for various collision centrality classes up to $p_{\rm{T}}$ $=$ 20 GeV$/c$. The $p_{\rm{T}}$-integrated yield ratio $\rm{K}^{*}(892)^{0}$$/$K in Pb-Pb collisions shows significant suppression relative to pp collisions and decreases towards more central collisions. In contrast, the $\phi(1020)$$/$K ratio does not show any suppression. Furthermore, the measured $\rm{K}^{*}(892)^{0}$$/$K ratio in central Pb-Pb collisions is significantly suppressed with respect to the expectations based on a thermal model calculation, while the $\phi(1020)$$/$K ratio agrees with the model prediction. These measurements are an experimental demonstration of rescattering of $\rm{K}^{*}(892)^{0}$ decay products in the hadronic phase of the collisions. The $\rm{K}^{*}(892)^{0}$$/$K yield ratios in Pb-Pb and pp collisions are used to estimate the time duration between chemical and kinetic freeze-out, which is found to be $\sim$ 4-7 fm$/c$ for central collisions. The $p_{\rm{T}}$-differential ratios of $\rm{K}^{*}(892)^{0}$$/$K, $\phi(1020)$$/$K, $\rm{K}^{*}(892)^{0}$$/\pi$, $\phi(1020)$$/\pi$, $p/$$\rm{K}^{*}(892)^{0}$ and $p/$$\phi(1020)$ are also presented for Pb-Pb and pp collisions at $\sqrt{s_{\rm{NN}}}$ $=$ 5.02 TeV. These ratios show that the rescattering effect is predominantly a low-$p_{\rm{T}}$ phenomenon.

20 data tables

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

$p_{\rm T}$-distributions of $\rm{K}^{*0}$ (average of particle and anti-particle) meson measured in pp collisions at $\sqrt{s}$ = 5.02 TeV.

$p_{\rm T}$-distributions of $\phi$ meson measured in Pb-Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV.

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Jet-hadron correlations measured relative to the second order event plane in Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 2.76 TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adler, Alexander ; et al.
Phys.Rev.C 101 (2020) 064901, 2020.
Inspire Record 1762358 DOI 10.17182/hepdata.93229

The Quark Gluon Plasma (QGP) produced in ultra relativistic heavy-ion collisions at the Large Hadron Collider (LHC) can be studied by measuring the modifications of jets formed by hard scattered partons which interact with the medium. We studied these modifications via angular correlations of jets with charged hadrons for jets with momenta 20 < $p_{\rm{T}}^{\rm{jet}}$ < 40 GeV/$c$ as a function of the associated particle momentum. The reaction plane fit (RPF) method is used in this analysis to remove the flow modulated background. The analysis of angular correlations for different orientations of the jet relative to the second order event plane allows for the study of the path length dependence of medium modifications to jets. We present the dependence of azimuthal angular correlations of charged hadrons with respect to the angle of the axis of a reconstructed jet relative to the event plane in Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 2.76 TeV. The dependence of particle yields associated with jets on the angle of the jet with respect to the event plane is presented. Correlations at different angles relative to the event plane are compared through ratios and differences of the yield. No dependence of the results on the angle of the jet with respect to the event plane is observed within uncertainties, which is consistent with no significant path length dependence of the medium modifications for this observable.

58 data tables

The near-side and away-side yield vs $p_{T}^{assoc}$ for $20<p_T^{jet}<40$ GeV/$c$ full jets of 30-50% centrality in Pb-Pb collisions. The background uncertainty is non-trivially correlated point-to-point. The correlated systematic uncertainties come from the shape uncertainty of the acceptance correction. There is an additional 5% global scale uncertainty.

The differences between out-of-plane and in-plane yields and mid-plane and in-plane yields on near-side and away-side vs $p_{T}^{assoc}$ for $20<p_T^{jet}<40$ GeV/$c$ full jets of 30-50% centrality in Pb-Pb collisions. The background uncertainty is non-trivially correlated point-to-point. The correlated systematic uncertainties come from the shape uncertainty of the acceptance correction. There is an additional 5% global scale uncertainty.

The ratios of out-of-plane to in-plane yields and mid-plane to in-plane yields on near-side and away-side vs $p_{T}^{assoc}$ for $20<p_T^{jet}<40$ GeV/$c$ full jets of 30-50% centrality in Pb-Pb collisions. The background uncertainty is non-trivially correlated point-to-point. The correlated systematic uncertainties come from the shape uncertainty of the acceptance correction.

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Measurement of electrons from heavy-flavour hadron decays as a function of multiplicity in p-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adhya, Souvik Priyam ; et al.
JHEP 02 (2020) 077, 2020.
Inspire Record 1762347 DOI 10.17182/hepdata.94314

The multiplicity dependence of electron production from heavy-flavour hadron decays as a function of transverse momentum was measured in p-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV using the ALICE detector at the LHC. The measurement was performed in the centre-of-mass rapidity interval $-1.07 < y_{\rm cms} < 0.14$ and transverse momentum interval 2 $< p_{\rm T} <$ 16 GeV/$c$. The multiplicity dependence of the production of electrons from heavy-flavour hadron decays was studied by comparing the $p_{\rm T}$ spectra measured for different multiplicity classes with those measured in pp collisions ($Q_{\rm pPb}$) and in peripheral p-Pb collisions ($Q_{\rm CP}$). The $Q_{\rm pPb}$ results obtained are consistent with unity within uncertainties in the measured $p_{\rm T}$ interval and event classes. This indicates that heavy-flavour decay electron production is consistent with binary scaling and independent of the geometry of the collision system. Additionally, the results suggest that cold nuclear matter effects are negligible within uncertainties, in the production of heavy-flavour decay electrons at midrapidity in p-Pb collisions.

13 data tables

$p_{\rm T}$-differential invariant cross section of electrons from heavy-flavour hadron decays in p--Pb collisions

$p_{\rm T}$-differential invariant cross section of electrons from heavy-flavour hadron decays in p--Pb collisions in 0--20\% centrality

$p_{\rm T}$-differential invariant cross section of electrons from heavy-flavour hadron decays in p--Pb collisions in 20--40\% centrality

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Underlying Event properties in pp collisions at $\sqrt{s}$ = 13 TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adler, Alexander ; et al.
JHEP 04 (2020) 192, 2020.
Inspire Record 1762350 DOI 10.17182/hepdata.94414

This article reports measurements characterizing the Underlying Event (UE) associated with hard scatterings at midrapidity in pp collisions at $\sqrt{s}=13$ TeV. The hard scatterings are identified by the leading particle, the charged particle with the highest transverse momentum ($p_{\rm T}^{\rm leading}$) in the event. Charged-particle number and summed transverse-momentum densities are measured in different azimuthal regions defined with respect to the leading particle direction: Toward, Transverse, and Away. The Toward and Away regions contain the fragmentation products of the hard scatterings in addition to the UE contribution, whereas particles in the Transverse region are expected to originate predominantly from the UE. The study is performed as a function of $p_{\rm T}^{\rm leading}$ with three different $p_{\rm T}$ thresholds for the associated particles, $p_{\rm T}^{\rm min} >$ 0.15, 0.5, and 1.0 GeV/$c$. The charged-particle density in the Transverse region rises steeply for low values of $p_{\rm T}^{\rm leading}$ and reaches a plateau. The results confirm the trend that the charged-particle density in the Transverse region shows a stronger increase with $\sqrt{s}$ than the inclusive charged-particle density at midrapidity. The UE activity is increased by approximately 20% when going from 7 to 13 TeV. The plateau in the Transverse region ($5 < p_{\rm T}^{\rm leading} < ~ 40$ GeV/$c$ ) is further characterized by the probability distribution of its charged-particle multiplicity normalized to its average value (relative transverse activity, $R_{T}$) and the mean transverse momentum as a function of $R_{T}$. Experimental results are compared to model calculations using PYTHIA 8 and EPOS LHC. The overall agreement between models and data is within 30%. These measurements provide new insights on the interplay between hard scatterings and the associated UE in pp collisions.

5 data tables

Fig. 3: Number density $N_{ch}$ (left) and $\\Sigma p_{T}$ (right) distributions as a function of $p_{T}^{leading}$ in Toward, Transverse, and Away regions for $p_{T}^{track} >$ 0.15 GeV/$c$. The shaded areas represent the systematic uncertainties and vertical error bars indicate statistical uncertainties.

Fig. 9: R_T probability distribution in the Transverse region for $p_{T}^{track} >$ 0.15 GeV/$c$ and $|\\eta|<$ 0.8. The result (solid circles) is compared to the PYTHIA 8 and EPOS LHC calculations (lines). The red line represents the result of the NBD fit, where the multiplicity is scaled by its mean value, m. The parameter k is related to the standard deviation of the distribution via $\\sigma$ = $\\sqrt{ \\frac{1}{m} + \\frac{1}{k} }$. The open boxes represent the systematic uncertainties and vertical error bars indicate statistical uncertainties. No uncertainties are shown for the MC calculations. The bottom panel shows the ratio between the NBD fit, as well as those of the MC to the data.

Fig. 10: $<p_{T}>$ in the Transverse region as a function of $R_{T}$ for $p_{T}^{track} >$ 0.15 GeV/$c$ and $|\\eta|<$ 0.8. Data (solid circles) are compared to the results of PYTHIA 8 and EPOS LHC calculations (lines). The open boxes represent the systematic uncertainties and vertical error bars indicate statistical uncertainties. No uncertainties are shown for the MC calculations. The bottom panel shows the ratio of the MC to data.

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Production of (anti-)$^3$He and (anti-)$^3$H in p-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adler, Alexander ; et al.
Phys.Rev.C 101 (2020) 044906, 2020.
Inspire Record 1762356 DOI 10.17182/hepdata.94416

The transverse momentum ($p_{\rm{T}}$) differential yields of (anti-)$^3$He and (anti-)$^3$H measured in p-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV with ALICE at the Large Hadron Collider (LHC) are presented. The ratios of the $p_{\rm{T}}$-integrated yields of (anti-)$^3$He and (anti-)$^3$H to the proton yields are reported, as well as the $p_{\rm{T}}$ dependence of the coalescence parameters $B_3$ for (anti-)$^3$He and (anti-)$^3$H. For (anti-)$^3$He, the results obtained in four classes of the mean charged-particle multiplicity density are also discussed. These results are compared to predictions from a canonical statistical hadronization model and coalescence approaches. An upper limit on the total yield of $^4\bar{\mathrm{He}}$ is determined.

24 data tables

Transverse momentum spectra of (anti-)$^3\mathrm{He}$ measured in $\mathrm{INEL}>0$ p--Pb collisions at $\sqrt{s_\mathrm{NN}} = 5.02$

Transverse momentum spectra of (anti-)$^3\mathrm{H}$ measured in $\mathrm{INEL}>0$ p--Pb collisions at $\sqrt{s_\mathrm{NN}} = 5.02$

$^3\overline{\mathrm{He}} /\,^3\mathrm{He}$ ratio in $\mathrm{INEL}>0$ p--Pb collisions at $\sqrt{s_\mathrm{NN}} = 5.02$

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Centrality and transverse momentum dependence of inclusive J/$\psi$ production at midrapidity in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adler, Alexander ; et al.
Phys.Lett.B 805 (2020) 135434, 2020.
Inspire Record 1762353 DOI 10.17182/hepdata.94384

The inclusive J/$\psi$ meson production in Pb-Pb collisions at a center-of-mass energy per nucleon-nucleon collision of $\sqrt{s_{\rm NN}}$ = 5.02 TeV at midrapidity ($|y|$ < 0.9) is reported by the ALICE Collaboration. The measurements are performed in the dielectron decay channel, as a function of event centrality and J/$\psi$ transverse momentum $p_{\rm T}$, down to $p_{\rm T}$ = 0 GeV/$c$. The J/$\psi$ mean transverse momentum $\langle p_{\rm T} \rangle$ and $r_{\rm AA}$ ratio, defined as $\langle p^{\rm 2}_{\rm T} \rangle_{\rm PbPb}/\langle p^{\rm 2}_{\rm T} \rangle_{\rm pp}$, are evaluated. Both observables show a centrality dependence decreasing towards central (head-on) collisions. The J/$\psi$ nuclear modification factor $R_{\rm AA}$ exhibits a strong $p_{\rm T}$ dependence with a large suppression at high $p_{\rm T}$ and an increase to unity for decreasing $p_{\rm T}$. When integrating over the measured momentum range $p_{\rm T}$ < 10 GeV/$c$, the J/$\psi$ $R_{\rm AA}$ shows a weak centrality dependence. Each measurement is compared with results at lower center-of-mass energies and with ALICE measurements at forward rapidity, as well as to theory calculations. All reported features of the J/$\psi$ production at low $p_{\rm T}$ are consistent with a dominant contribution to the J/$\psi$ yield originating from charm quark (re)combination.

7 data tables

Transverse momentum dependence of the inclusive J/$\psi$ yields in Pb$-$Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV at midrapidity in the centrality intervals 0$-$20%, 20$-$40%, and 40$-$90%.

Inclusive J/$\psi$ $\langle p_{\rm T} \rangle$ in Pb$-$Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV at midrapidity as a function of the mean number of participant nucleons.

Inclusive J/$\psi$ $r_{\rm AA} = \langle p^{2}_{\rm T} \rangle_{\rm PbPb} / \langle p^{2}_{\rm T} \rangle_{\rm pp}$ in Pb$-$Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV at midrapidity as a function of the mean number of participant nucleons. The correlated systematic uncertainty due to the pp reference is not included and amounts to 4.7%, shown as the red box around unity in the paper figure.

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Global baryon number conservation encoded in net-proton fluctuations measured in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adler, Alexander ; et al.
Phys.Lett.B 807 (2020) 135564, 2020.
Inspire Record 1762338 DOI 10.17182/hepdata.95244

Experimental results are presented on event-by-event net-proton fluctuation measurements in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV, recorded by the ALICE detector at the CERN LHC. These measurements have as their ultimate goal an experimental test of Lattice QCD (LQCD) predictions on second and higher order cumulants of net-baryon distributions to search for critical behavior near the QCD phase boundary. Before confronting them with LQCD predictions, account has to be taken of correlations stemming from baryon number conservation as well as fluctuations of participating nucleons. Both effects influence the experimental measurements and are usually not considered in theoretical calculations. For the first time, it is shown that event-by-event baryon number conservation leads to subtle long-range correlations arising from very early interactions in the collisions.

14 data tables

Measured second cumulants of net-proton distributions.

Second cumulants of the Skellam distribution.

Measured second cumulants of protons.

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$ϒ$ production in p–Pb collisions at $\sqrt{s_{NN}}$=8.16 TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adler, Alexander ; et al.
Phys.Lett.B 806 (2020) 135486, 2020.
Inspire Record 1762360 DOI 10.17182/hepdata.95539

$\Upsilon$ production in p-Pb interactions is studied at the centre-of-mass energy per nucleon-nucleon collision $\sqrt{s_{\rm{NN}}}$ = 8.16 TeV with the ALICE detector at the CERN LHC. The measurement is performed reconstructing bottomonium resonances via their dimuon decay channel, in the centre-of-mass rapidity intervals $2.03 < y_{\rm{cms}} < 3.53$ and $-4.46 < y_{\rm{cms}} < -2.96$, down to zero transverse momentum. In this work, results on the inclusive $\Upsilon(1\rm{S})$ production cross section as a function of rapidity and transverse momentum are presented. The corresponding nuclear modification factor shows a suppression of the $\Upsilon(1\rm{S})$ yields with respect to pp collisions, both at forward and backward rapidity. This suppression is stronger in the low transverse momentum region and shows no significant dependence on the centrality of the interactions. Furthermore, the $\Upsilon(2\rm{S})$ nuclear modification factor is also evaluated, suggesting a suppression similar to that of the $\Upsilon(1\rm{S})$. A first measurement of the $\Upsilon(3\rm{S})$ has also been performed. Finally, results are compared with previous measurements performed by ALICE in p-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV and with theoretical calculations.

18 data tables

$\Upsilon$(1S) differential cross section as a function of $y_{\rm cms}$, in p--Pb collisions at $\sqrt{s_{\rm NN}}$ = 8.16 TeV. The first uncertainty is statistical, while the second is the systematic.

$\Upsilon$(2S) differential cross section times as a function of $y_{\rm cms}$, in p--Pb collisions at $\sqrt{s_{\rm NN}}$ = 8.16 TeV. The first uncertainty is statistical, while the second is the systematic.

$\Upsilon$(3S) differential cross section as a function of $y_{\rm cms}$, in p--Pb collisions at $\sqrt{s_{\rm NN}}$ = 8.16 TeV. The first uncertainty is statistical, while the second is the systematic.

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Longitudinal and azimuthal evolution of two-particle transverse momentum correlations in Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 2.76 TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adler, Alexander ; et al.
Phys.Lett.B 804 (2020) 135375, 2020.
Inspire Record 1762340 DOI 10.17182/hepdata.93887

This paper presents the first measurements of the charge independent (CI) and charge dependent (CD) two-particle transverse momentum correlators $G_{2}^{\rm CI}$ and $G_{2}^{\rm CD}$ in Pb--Pb collisions at $\sqrt{s_{\text{NN}}} = 2.76\;\text{\TeVe}$ by the ALICE collaboration. The two-particle transverse momentum correlator $G_{2}$ was introduced as a measure of the momentum current transfer between neighbouring system cells. The correlators are measured as a function of pair separation in pseudorapidity ($\Delta \eta$) and azimuth ($\Delta \varphi$) and as a function of collision centrality. From peripheral to central collisions, the correlator $G_{2}^{\rm CI}$ exhibits a longitudinal broadening while undergoing a monotonic azimuthal narrowing. By contrast, $G_{2}^{\rm CD}$ exhibits a narrowing along both dimensions. These features are not reproduced by models such as HIJING and AMPT. However, the observed narrowing of the correlators from peripheral to central collisions is expected to result from the stronger transverse flow profiles produced in more central collisions and the longitudinal broadening is predicted to be sensitive to momentum currents and the shear viscosity per unit of entropy density $\eta/s$ of the matter produced in the collisions. The observed broadening is found to be consistent with the hypothesized lower bound of $\eta/s$ and is in qualitative agreement with values obtained from anisotropic flow measurements.

12 data tables

Two-particle transverse momentum correlation $G_{2}^{\rm CI}$ for central (0-5%) Pb--Pb collisions at $\sqrt{s_{\rm NN}}=2.76\;\text{TeV}$.

Two-particle transverse momentum correlation $G_{2}^{\rm CI}$ for semi-central (30-40%) Pb--Pb collisions at $\sqrt{s_{\rm NN}}=2.76\;\text{TeV}$.

Two-particle transverse momentum correlation $G_{2}^{\rm CI}$ for perippheral (70-80%) Pb--Pb collisions at $\sqrt{s_{\rm NN}}=2.76\;\text{TeV}$.

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Azimuthal correlations of prompt D mesons with charged particles in pp and p-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adler, Alexander ; et al.
2019.
Inspire Record 1762354 DOI 10.17182/hepdata.95121

The measurement of the azimuthal-correlation function of prompt D mesons with charged particles in pp collisions at $\sqrt{s}$ = 5.02 TeV and p-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV with the ALICE detector at the LHC is reported. The D$^{\rm 0}$, D$^{\rm +}$, and D$^{\rm *+}$ mesons, together with their charge conjugates, were reconstructed at midrapidity in the transverse momentum interval 3 < $p_{\rm T}$ < 24 GeV/c and correlated with charged particles having $p_{\rm T}$ > 0.3 GeV/c and pseudorapidity $|\eta| <$ 0.8. The properties of the correlation peaks appearing in the near- and away-side regions (for $\Delta \varphi \approx$ 0 and $\Delta \varphi \approx \pi$, respectively) were extracted via a fit to the azimuthal correlation functions. The shape of the correlation functions and the near- and away-side peak features are found to be consistent in pp and p-Pb collisions, showing no modifications due to nuclear effects within uncertainties. The results are compared with predictions from Monte Carlo simulations performed with the PYTHIA, POWHEG+PYTHIA, HERWIG, and EPOS 3 event generators.

51 data tables

Comparison of the azimuthal-correlation distributions of D mesons (average of D$^{0}$, D$^{+}$, D$^{*+}$) with $3 < p_{\rm T} < 5$ GeV/$c$ and charged particles with $p_{\rm T} > 0.3$ GeV/$c$, in pp collisions at $\sqrt{s} = 5.02$ TeV and p-Pb collisions at $\sqrt{s_{NN}} = 5.02$ TeV, after baseline subtraction. Rapidity range for the D mesons are $|y^{\rm D}_{\rm cms}| < 0.5$ in pp, $-0.96 < y^{\rm D}_{\rm cms} < 0.04$ in p-Pb. Correlations are integrated for $|\Delta\eta|=|\eta_{\rm ch}-\eta_{\rm D}| < 1$. The azimuthal-correlation distributions are reported in the range $0 < \Delta\varphi < \pi$.

Comparison of the azimuthal-correlation distributions of D mesons (average of D$^{0}$, D$^{+}$, D$^{*+}$) with $5 < p_{\rm T} < 8$ GeV/$c$ and charged particles with $p_{\rm T} > 0.3$ GeV/$c$, in pp collisions at $\sqrt{s} = 5.02$ TeV and p-Pb collisions at $\sqrt{s_{NN}} = 5.02$ TeV, after baseline subtraction. Rapidity range for the D mesons are $|y^{\rm D}_{\rm cms}| < 0.5$ in pp, $-0.96 < y^{\rm D}_{\rm cms} < 0.04$ in p-Pb. Correlations are integrated for $|\Delta\eta|=|\eta_{\rm ch}-\eta_{\rm D}| < 1$. The azimuthal-correlation distributions are reported in the range $0 < \Delta\varphi < \pi$.

Comparison of the azimuthal-correlation distributions of D mesons (average of D$^{0}$, D$^{+}$, D$^{*+}$) with $8 < p_{\rm T} < 16$ GeV/$c$ and charged particles with $p_{\rm T} > 0.3$ GeV/$c$, in pp collisions at $\sqrt{s} = 5.02$ TeV and p-Pb collisions at $\sqrt{s_{NN}} = 5.02$ TeV, after baseline subtraction. Rapidity range for the D mesons are $|y^{\rm D}_{\rm cms}| < 0.5$ in pp, $-0.96 < y^{\rm D}_{\rm cms} < 0.04$ in p-Pb. Correlations are integrated for $|\Delta\eta|=|\eta_{\rm ch}-\eta_{\rm D}| < 1$. The azimuthal-correlation distributions are reported in the range $0 < \Delta\varphi < \pi$.

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Probing the effects of strong electromagnetic fields with charge-dependent directed flow in Pb-Pb collisions at the LHC

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adler, Alexander ; et al.
Phys.Rev.Lett. 125 (2020) 022301, 2020.
Inspire Record 1762367 DOI 10.17182/hepdata.95654

The first measurement at the LHC of charge-dependent directed flow ($v_{1}$) relative to the spectator plane is presented for Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV. Results are reported for charged hadrons and $\rm D^{0}$ mesons for the transverse momentum intervals $p_{\rm T}>0.2$ GeV/$c$ and $3<p_{\rm T}<$ 6 GeV/$c$ in the 5-40% and 10-40% centrality classes, respectively. The difference between the positively and negatively charged hadron $v_{1}$ is found to have a positive slope as a function of pseudorapidity $\eta$, ${\rm d}\Delta{v_1}/{\rm d}\eta=$[1.68 $\pm$ 0.49 (stat.) $\pm$ 0.41 (syst.)] $\times 10^{-4}$, with a $2.6\sigma$ significance. The same measurement for $\rm D^{0}$ and $\rm\bar{D}{}^0$ mesons yields a positive value ${\rm d}\Delta{v_1}/{\rm d}\eta$= [4.9 $\pm$ 1.7 (stat.) $\pm$ 0.6 (syst.)]$\times 10^{-1}$, which is about three orders of magnitude larger than the one of the charged hadrons, and is larger than zero with significance of $2.7\sigma$. These measurements can provide new insights into the effects of the strong electromagnetic field and the initial tilt of matter created in non-central heavy-ion collisions on the dynamics of light (u, d, and s) and heavy (c) quarks. The large difference between the observed $\Delta{v_1}$ of charged hadrons and $\rm D^{0}$ mesons may reflect different sensitivity of the charm and light quarks to the early time dynamics of a heavy-ion collision. These observations challenge some of the recent theoretical calculations incorporating effects of the strong electromagnetic field, which predicted a negative and an order of magnitude smaller value of ${\rm d}\Delta{v_1}/{\rm d}\eta$ for both light-flavour and charmed hadrons.

8 data tables

Directed flow positive hadrons 5-40%

Directed flow negative hadrons 5-40%

Delta Directed flow hadrons

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First measurement of $\Lambda_c$ baryon production in Au+Au collisions at $\sqrt{s_{\rm NN}}$ = 200 GeV

The STAR collaboration Adam, Jaroslav ; Adamczyk, Leszek ; Adams, Joseph ; et al.
Phys.Rev.Lett. 124 (2020) 172301, 2020.
Inspire Record 1762441 DOI 10.17182/hepdata.94228

We report on the first measurement of the charmed baryon $\Lambda_c^{\pm}$ production at midrapidity ($|y|$ $<$ 1) in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV collected by the STAR experiment at the Relativistic Heavy Ion Collider. The $\Lambda_c$/$D^0$ (denoting ($\Lambda_c^++\Lambda_c^-$)/($D^0+\bar{D^0}$)) yield ratio is measured to be 1.08 $\pm$ 0.16 (stat.) $\pm$ 0.26 (sys.) in the 0--20% most central Au+Au collisions for the transverse momentum ($p_T$) range 3 $<$ $p_T$ $<$ 6 GeV/$c$. This is significantly larger than the PYTHIA model calculations for $p+p$ collisions. The measured $\Lambda_c$/$D^0$ ratio, as a function of $p_T$ and collision centrality, is comparable to the baryon-to-meson ratios for light and strange hadrons in Au+Au collisions. Model calculations including coalescence hadronization for charmed baryon and meson formation reproduce the features of our measured $\Lambda_c$/$D^0$ ratio.

7 data tables

The $pK\pi$ invariant mass distributions (Counts per 10 MeV/c^2 bin) for right-sign combinations in Au+Au collisions at $\sqrt{s_{\rm NN}}$ = 200\,GeV for 0--20\% centrality class.

The $pK\pi$ invariant mass distributions (Counts per 10 MeV/c^2 bin) for wrong-sign combinations, scaled by 1/3, in Au+Au collisions at $\sqrt{s_{\rm NN}}$ = 200\,GeV for 0--20\% centrality class.

The $pK\pi$ invariant mass distributions (Counts per 10 MeV/c^2 bin) for right-sign combinations in Au+Au collisions at $\sqrt{s_{\rm NN}}$ = 200\,GeV for 10--80\% centrality class.

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Measurement of electrons from semileptonic heavy-flavour hadron decays at midrapidity in pp and Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adhya, Souvik Priyam ; et al.
Phys.Lett.B 804 (2020) 135377, 2020.
Inspire Record 1759860 DOI 10.17182/hepdata.93923

The differential invariant yield as a function of transverse momentum ($p_\mathrm{T}$) of electrons from semileptonic heavy-flavour hadron decays was measured at midrapidity in central (0-10%), semi-central (30-50%) and peripheral (60-80%) lead-lead (Pb-Pb) collisions at $\sqrt{s_{\mathrm{NN}}}=5.02\text{ TeV}$ in the $p_{\mathrm{T}}$ intervals 0.5-26 GeV/$c$ (0-10% and 30-50%) and 0.5-10 GeV/$c$ (60-80%). The production cross section in proton-proton (pp) collisions at $\sqrt{s}=5.02$ TeV was measured as well in $0.5<p_\mathrm{T}<10$ GeV/$c$ and it lies close to the upper band of perturbative QCD calculation uncertainties up to $p_\mathrm{T}=5$ GeV/$c$ and close to the mean value for larger $p_\mathrm{T}$. The modification of the electron yield with respect to what is expected for an incoherent superposition of nucleon-nucleon collisions is evaluated by measuring the nuclear modification factor $R_{\mathrm{AA}}$. The measurement of the $R_{\mathrm{AA}}$ in different centrality classes allows in-medium energy loss of charm and beauty quarks to be investigated. The $R_{\mathrm{AA}}$ shows a suppression with respect to unity at intermediate $p_\mathrm{T}$, which increases while moving towards more central collisions. Moreover, the measured $R_{\mathrm{AA}}$ is sensitive to the modification of the parton distribution functions (PDF) in nuclei, like nuclear shadowing, which causes a suppression of the heavy-quark production at low $p_\mathrm{T}$ in heavy-ion collisions at LHC.

7 data tables

HFe cross section in pp

HFe cross section in Pb-Pb, 0-10 centrality

HFe cross section in Pb-Pb, 30-50 centrality

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Measurement of the (anti-)$^{3}$He elliptic flow in Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adhya, Souvik Priyam ; et al.
Phys.Lett.B 805 (2020) 135414, 2020.
Inspire Record 1760170 DOI 10.17182/hepdata.95240

The elliptic flow ($v_{2}$) of (anti-)$^{3}$He is measured in Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV in the transverse-momentum ($p_{\rm{T}}$) range of 2-6 GeV/$c$ for the centrality classes 0-20%, 20-40%, and 40-60% using the event-plane method. This measurement is compared to that of pions, kaons, and protons at the same center-of-mass energy. A clear mass ordering is observed at low $p_{\rm{T}}$, as expected from relativistic hydrodynamics. The violation of the scaling of $v_{2}$ with the number of constituent quarks at low $p_{\rm{T}}$, already observed for identified hadrons and deuterons at LHC energies, is confirmed also for (anti-)$^{3}$He. The elliptic flow of (anti-)$^{3}$He is underestimated by the Blast-Wave model and overestimated by a simple coalescence approach based on nucleon scaling. The elliptic flow of (anti-)$^{3}$He measured in the centrality classes 0-20% and 20-40% is well described by a more sophisticated coalescence model where the phase-space distributions of protons and neutrons are generated using the iEBE-VISHNU hybrid model with AMPT initial conditions.

4 data tables

Event-plane resolution $R_{\Psi_{2}}$ of the second harmonic as a function of the collision centrality.

Elliptic flow ($v_{2}$) of (anti-)$^{3}$He measured in Pb-Pb collisions at \sqrt{s_{\mathrm{NN}}} = 5.02 TeV for the centrality classes 0--20$\%$, 20--40$\%$, and 40--60$\%$. The statistical uncertainties are shown as vertical bars, systematic uncertainties as boxes.

Elliptic flow ($v_{2}$) of (anti-)$^{3}$He measured in Pb-Pb collisions at \sqrt{s_{\mathrm{NN}}} = 5.02 TeV for the centrality classes 0--20$\%$, 20--40$\%$, and 40--60$\%$. The statistical uncertainties are shown as vertical bars, systematic uncertainties as boxes.

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Measurements of inclusive jet spectra in pp and central Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adler, Alexander ; et al.
Phys.Rev.C 101 (2020) 034911, 2020.
Inspire Record 1755387 DOI 10.17182/hepdata.93739

This article reports measurements of the $p_{\rm{T}}$-differential inclusive jet cross-section in pp collisions at $\sqrt{s}$ = 5.02 TeV and the $p_{\rm{T}}$-differential inclusive jet yield in Pb-Pb 0-10% central collisions at $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV. Jets were reconstructed at mid-rapidity with the ALICE tracking detectors and electromagnetic calorimeter using the anti-$k_{\rm{T}}$ algorithm. For pp collisions, we report jet cross-sections for jet resolution parameters $R=0.1-0.6$ over the range $20<p_{\rm{T,jet}}<140$ GeV/$c$, as well as the jet cross-section ratios of different $R$, and comparisons to two next-to-leading-order (NLO)-based theoretical predictions. For Pb-Pb collisions, we report the $R=0.2$ and $R=0.4$ jet spectra for $40<p_{\rm{T,jet}}<140$ GeV/$c$ and $60<p_{\rm{T,jet}}<140$ GeV/$c$, respectively. The scaled ratio of jet yields observed in Pb-Pb to pp collisions, $R_{\rm{AA}}$, is constructed, and exhibits strong jet quenching and a clear $p_{\rm{T}}$-dependence for $R=0.2$. No significant $R$-dependence of the jet $R_{\rm{AA}}$ is observed within the uncertainties of the measurement. These results are compared to several theoretical predictions.

33 data tables

Fig. 1 Left, data for jet radius R=0.1. Unfolded pp full jet cross-section at $\sqrt{s}$ = 5.02 TeV for R = 0.1 − 0.6. No leading track requirement is imposed.

Fig. 1 Left, data for jet radius R=0.2. Unfolded pp full jet cross-section at $\sqrt{s}$ = 5.02 TeV for R = 0.1 − 0.6. No leading track requirement is imposed.

Fig. 1 Left, data for jet radius R=0.3. Unfolded pp full jet cross-section at $\sqrt{s}$ = 5.02 TeV for R = 0.1 − 0.6. No leading track requirement is imposed.

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Studies of J/$\psi$ production at forward rapidity in Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adhya, Souvik Priyam ; et al.
JHEP 02 (2020) 041, 2020.
Inspire Record 1753083 DOI 10.17182/hepdata.93341

The inclusive J/$\psi$ production in Pb-Pb collisions at the center-of-mass energy per nucleon pair $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV, measured with the ALICE detector at the CERN LHC, is reported. The J/$\psi$ meson is reconstructed via the dimuon decay channel at forward rapidity ($2.5<y<4$) down to zero transverse momentum. The suppression of the J/$\psi$ yield in Pb-Pb collisions with respect to binary-scaled pp collisions is quantified by the nuclear modification factor ($R_{\rm{AA}}$). The $R_{\rm{AA}}$ at $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV is presented and compared with previous measurements at $\sqrt{s_{\rm{NN}}}$ = 2.76 TeV as a function of the centrality of the collision, and of the J/$\psi$ transverse momentum and rapidity. The inclusive J/$\psi$ $R_{\rm{AA}}$ shows a suppression increasing toward higher $p_{\rm{T}}$, with a steeper dependence for central collisions. The modification of the J/$\psi$ average $p_{\rm{T}}$ and $p_{\rm{T}}^{2}$ is also studied. Comparisons with the results of models based on a transport equation and on statistical hadronization are also carried out.

43 data tables

Transverse momentum dependence (in 0-90% centrality class) of the inclusive J/$\psi$ $R_{\rm AA}$. The first uncertainty is statistical, the second is the uncorrelated systematic, while the third one is a $p_{\rm T}$-correlated systematic uncertainty.

The minimum and maximum variations for the $R_{\rm AA}$ of prompt J/$\psi$ with respect to the $R_{\rm AA}$ values of inclusive J/$\psi$ reported in Table 1. The variations correspond to two extreme hypotheses on the unknown contribution of non-prompt J/$\psi$.

Transverse momentum dependence (in 0-90% centrality class) of the ratio of the inclusive J/$\psi$ $R_{\rm AA}$ at $\sqrt{s_{NN}}$= 5.02 and 2.76 TeV. The first uncertainty is statistical, the second is the uncorrelated systematic, while the third one is a $p_{\rm T}$-correlated systematic uncertainty.

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