Charged-hadron production in $pp$, $p$+Pb, Pb+Pb, and Xe+Xe collisions at $\sqrt{s_{_\text{NN}}}=5$ TeV with the ATLAS detector at the LHC

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abeling, Kira ; et al.
JHEP 07 (2023) 074, 2023.
Inspire Record 2601282 DOI 10.17182/hepdata.135676

This paper presents measurements of charged-hadron spectra obtained in $pp$, $p$+Pb, and Pb+Pb collisions at $\sqrt{s}$ or $\sqrt{s_{_\text{NN}}}=5.02$ TeV, and in Xe+Xe collisions at $\sqrt{s_{_\text{NN}}}=5.44$ TeV. The data recorded by the ATLAS detector at the LHC have total integrated luminosities of 25 pb${}^{-1}$, 28 nb${}^{-1}$, 0.50 nb${}^{-1}$, and 3 $\mu$b${}^{-1}$, respectively. The nuclear modification factors $R_{p\text{Pb}}$ and $R_\text{AA}$ are obtained by comparing the spectra in heavy-ion and $pp$ collisions in a wide range of charged-particle transverse momenta and pseudorapidity. The nuclear modification factor $R_{p\text{Pb}}$ shows a moderate enhancement above unity with a maximum at $p_{\mathrm{T}} \approx 3$ GeV; the enhancement is stronger in the Pb-going direction. The nuclear modification factors in both Pb+Pb and Xe+Xe collisions feature a significant, centrality-dependent suppression. They show a similar distinct $p_{\mathrm{T}}$-dependence with a local maximum at $p_{\mathrm{T}} \approx 2$ GeV and a local minimum at $p_{\mathrm{T}} \approx 7$ GeV. This dependence is more distinguishable in more central collisions. No significant $|\eta|$-dependence is found. A comprehensive comparison with several theoretical predictions is also provided. They typically describe $R_\text{AA}$ better in central collisions and in the $p_{\mathrm{T}}$ range from about 10 to 100 GeV.

140 data tables

- - - - - - - - - - - - - - - - - - - - <br><b>charged-hadron spectra:</b> <br><i>pp reference:</i>&nbsp;&nbsp; <a href="?version=1&table=Table1">for p+Pb</a>&nbsp;&nbsp; <a href="?version=1&table=Table10">for Pb+Pb</a>&nbsp;&nbsp; <a href="?version=1&table=Table19">for Xe+Xe</a>&nbsp;&nbsp; <br><i>p+Pb:</i>&nbsp;&nbsp; <a href="?version=1&table=Table2">0-5%</a>&nbsp;&nbsp; <a href="?version=1&table=Table3">5-10%</a>&nbsp;&nbsp; <a href="?version=1&table=Table4">10-20%</a>&nbsp;&nbsp; <a href="?version=1&table=Table5">20-30%</a>&nbsp;&nbsp; <a href="?version=1&table=Table6">30-40%</a>&nbsp;&nbsp; <a href="?version=1&table=Table7">40-60%</a>&nbsp;&nbsp; <a href="?version=1&table=Table8">60-90%</a>&nbsp;&nbsp; <a href="?version=1&table=Table9">0-90%</a>&nbsp;&nbsp; <br><i>Pb+Pb:</i>&nbsp;&nbsp; <a href="?version=1&table=Table11">0-5%</a>&nbsp;&nbsp; <a href="?version=1&table=Table12">5-10%</a>&nbsp;&nbsp; <a href="?version=1&table=Table13">10-20%</a>&nbsp;&nbsp; <a href="?version=1&table=Table14">20-30%</a>&nbsp;&nbsp; <a href="?version=1&table=Table15">30-40%</a>&nbsp;&nbsp; <a href="?version=1&table=Table16">40-50%</a>&nbsp;&nbsp; <a href="?version=1&table=Table17">50-60%</a>&nbsp;&nbsp; <a href="?version=1&table=Table18">60-80%</a>&nbsp;&nbsp; <br><i>Xe+Xe:</i>&nbsp;&nbsp; <a href="?version=1&table=Table20">0-5%</a>&nbsp;&nbsp; <a href="?version=1&table=Table21">5-10%</a>&nbsp;&nbsp; <a href="?version=1&table=Table22">10-20%</a>&nbsp;&nbsp; <a href="?version=1&table=Table23">20-30%</a>&nbsp;&nbsp; <a href="?version=1&table=Table24">30-40%</a>&nbsp;&nbsp; <a href="?version=1&table=Table25">40-50%</a>&nbsp;&nbsp; <a href="?version=1&table=Table26">50-60%</a>&nbsp;&nbsp; <a href="?version=1&table=Table27">60-80%</a>&nbsp;&nbsp; </br>- - - - - - - - - - - - - - - - - - - - <br><b>nuclear modification factors (p<sub>T</sub>):</b> <br><i>R<sub>pPb</sub>:</i>&nbsp;&nbsp; <a href="?version=1&table=Table28">0-5%</a>&nbsp;&nbsp; <a href="?version=1&table=Table29">5-10%</a>&nbsp;&nbsp; <a href="?version=1&table=Table30">10-20%</a>&nbsp;&nbsp; <a href="?version=1&table=Table31">20-30%</a>&nbsp;&nbsp; <a href="?version=1&table=Table32">30-40%</a>&nbsp;&nbsp; <a href="?version=1&table=Table33">40-60%</a>&nbsp;&nbsp; <a href="?version=1&table=Table34">60-90%</a>&nbsp;&nbsp; <a href="?version=1&table=Table35">0-90%</a>&nbsp;&nbsp; <br><i>R<sub>AA</sub> (Pb+Pb):</i>&nbsp;&nbsp; <a href="?version=1&table=Table36">0-5%</a>&nbsp;&nbsp; <a href="?version=1&table=Table37">5-10%</a>&nbsp;&nbsp; <a href="?version=1&table=Table38">10-20%</a>&nbsp;&nbsp; <a href="?version=1&table=Table39">20-30%</a>&nbsp;&nbsp; <a href="?version=1&table=Table40">30-40%</a>&nbsp;&nbsp; <a href="?version=1&table=Table41">40-50%</a>&nbsp;&nbsp; <a href="?version=1&table=Table42">50-60%</a>&nbsp;&nbsp; <a href="?version=1&table=Table43">60-80%</a>&nbsp;&nbsp; <br><i>R<sub>AA</sub> (Xe+Xe):</i>&nbsp;&nbsp; <a href="?version=1&table=Table44">0-5%</a>&nbsp;&nbsp; <a href="?version=1&table=Table45">5-10%</a>&nbsp;&nbsp; <a href="?version=1&table=Table46">10-20%</a>&nbsp;&nbsp; <a href="?version=1&table=Table47">20-30%</a>&nbsp;&nbsp; <a href="?version=1&table=Table48">30-40%</a>&nbsp;&nbsp; <a href="?version=1&table=Table49">40-50%</a>&nbsp;&nbsp; <a href="?version=1&table=Table50">50-60%</a>&nbsp;&nbsp; <a href="?version=1&table=Table51">60-80%</a>&nbsp;&nbsp; </br>- - - - - - - - - - - - - - - - - - - - <br><b>nuclear modification factors (y*/eta):</b> <br><i>R<sub>pPb</sub>:</i> <br>&nbsp;&nbsp;0-5%:&nbsp;&nbsp; <a href="?version=1&table=Table52">0.66-0.755GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table53">2.95-3.35GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table54">7.65-8.8GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table55">15.1-17.3GeV</a>&nbsp;&nbsp; <br>&nbsp;&nbsp;5-10%:&nbsp;&nbsp; <a href="?version=1&table=Table56">0.66-0.755GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table57">2.95-3.35GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table58">7.65-8.8GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table59">15.1-17.3GeV</a>&nbsp;&nbsp; <br>&nbsp;&nbsp;10-20%:&nbsp;&nbsp; <a href="?version=1&table=Table60">0.66-0.755GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table61">2.95-3.35GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table62">7.65-8.8GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table63">15.1-17.3GeV</a>&nbsp;&nbsp; <br>&nbsp;&nbsp;20-30%:&nbsp;&nbsp; <a href="?version=1&table=Table64">0.66-0.755GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table65">2.95-3.35GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table66">7.65-8.8GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table67">15.1-17.3GeV</a>&nbsp;&nbsp; <br>&nbsp;&nbsp;30-40%:&nbsp;&nbsp; <a href="?version=1&table=Table68">0.66-0.755GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table69">2.95-3.35GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table70">7.65-8.8GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table71">15.1-17.3GeV</a>&nbsp;&nbsp; <br>&nbsp;&nbsp;40-60%:&nbsp;&nbsp; <a href="?version=1&table=Table72">0.66-0.755GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table73">2.95-3.35GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table74">7.65-8.8GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table75">15.1-17.3GeV</a>&nbsp;&nbsp; <br>&nbsp;&nbsp;60-90%:&nbsp;&nbsp; <a href="?version=1&table=Table76">0.66-0.755GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table77">2.95-3.35GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table78">7.65-8.8GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table79">15.1-17.3GeV</a>&nbsp;&nbsp; <br>&nbsp;&nbsp;0-90%:&nbsp;&nbsp; <a href="?version=1&table=Table80">0.66-0.755GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table81">2.95-3.35GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table82">7.65-8.8GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table83">15.1-17.3GeV</a>&nbsp;&nbsp; <br><i>R<sub>AA</sub> (Pb+Pb):</i> <br>&nbsp;&nbsp;0-5%:&nbsp;&nbsp; <a href="?version=1&table=Table84">1.7-1.95GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table85">6.7-7.65GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table86">20-23GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table87">60-95GeV</a>&nbsp;&nbsp; <br>&nbsp;&nbsp;5-10%:&nbsp;&nbsp; <a href="?version=1&table=Table88">1.7-1.95GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table89">6.7-7.65GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table90">20-23GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table91">60-95GeV</a>&nbsp;&nbsp; <br>&nbsp;&nbsp;10-20%:&nbsp;&nbsp; <a href="?version=1&table=Table92">1.7-1.95GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table93">6.7-7.65GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table94">20-23GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table95">60-95GeV</a>&nbsp;&nbsp; <br>&nbsp;&nbsp;20-30%:&nbsp;&nbsp; <a href="?version=1&table=Table96">1.7-1.95GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table97">6.7-7.65GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table98">20-23GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table99">60-95GeV</a>&nbsp;&nbsp; <br>&nbsp;&nbsp;30-40%:&nbsp;&nbsp; <a href="?version=1&table=Table100">1.7-1.95GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table101">6.7-7.65GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table102">20-23GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table103">60-95GeV</a>&nbsp;&nbsp; <br>&nbsp;&nbsp;40-50%:&nbsp;&nbsp; <a href="?version=1&table=Table104">1.7-1.95GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table105">6.7-7.65GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table106">20-23GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table107">60-95GeV</a>&nbsp;&nbsp; <br>&nbsp;&nbsp;50-60%:&nbsp;&nbsp; <a href="?version=1&table=Table108">1.7-1.95GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table109">6.7-7.65GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table110">20-23GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table111">60-95GeV</a>&nbsp;&nbsp; <br>&nbsp;&nbsp;60-80%:&nbsp;&nbsp; <a href="?version=1&table=Table112">1.7-1.95GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table113">6.7-7.65GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table114">20-23GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table115">60-95GeV</a>&nbsp;&nbsp; <br><i>R<sub>AA</sub> (Xe+Xe):</i> <br>&nbsp;&nbsp;0-5%:&nbsp;&nbsp; <a href="?version=1&table=Table116">1.7-1.95GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table117">6.7-7.65GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table118">20-23GeV</a>&nbsp;&nbsp; <br>&nbsp;&nbsp;5-10%:&nbsp;&nbsp; <a href="?version=1&table=Table119">1.7-1.95GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table120">6.7-7.65GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table121">20-23GeV</a>&nbsp;&nbsp; <br>&nbsp;&nbsp;10-20%:&nbsp;&nbsp; <a href="?version=1&table=Table122">1.7-1.95GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table123">6.7-7.65GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table124">20-23GeV</a>&nbsp;&nbsp; <br>&nbsp;&nbsp;20-30%:&nbsp;&nbsp; <a href="?version=1&table=Table125">1.7-1.95GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table126">6.7-7.65GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table127">20-23GeV</a>&nbsp;&nbsp; <br>&nbsp;&nbsp;30-40%:&nbsp;&nbsp; <a href="?version=1&table=Table128">1.7-1.95GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table129">6.7-7.65GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table130">20-23GeV</a>&nbsp;&nbsp; <br>&nbsp;&nbsp;40-50%:&nbsp;&nbsp; <a href="?version=1&table=Table131">1.7-1.95GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table132">6.7-7.65GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table133">20-23GeV</a>&nbsp;&nbsp; <br>&nbsp;&nbsp;50-60%:&nbsp;&nbsp; <a href="?version=1&table=Table134">1.7-1.95GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table135">6.7-7.65GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table136">20-23GeV</a>&nbsp;&nbsp; <br>&nbsp;&nbsp;60-80%:&nbsp;&nbsp; <a href="?version=1&table=Table137">1.7-1.95GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table138">6.7-7.65GeV</a>&nbsp;&nbsp; <a href="?version=1&table=Table139">20-23GeV</a>&nbsp;&nbsp; <br>- - - - - - - - - - - - - - - - - - - -

Charged-hadron cross-section in pp collisions. The systematic uncertainties are described in the section 7 of the paper. The total systematic uncertainties are determined by adding the contributions from all relevant sources in quadrature.

Charged-hadron spectrum in the centrality interval 0-5% for p+Pb, divided by &#9001;TPPB&#9002;. The systematic uncertainties are described in the section 7 of the paper. The total systematic uncertainties are determined by adding the contributions from all relevant sources in quadrature.

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Two-particle Bose-Einstein correlations in pp collisions at ${\sqrt{s} = 13}$ TeV measured with the ATLAS detector at the LHC

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abbott, Dale ; et al.
Eur.Phys.J.C 82 (2022) 608, 2022.
Inspire Record 2027827 DOI 10.17182/hepdata.132012

This paper presents studies of Bose-Einstein correlations (BEC) in proton-proton collisions at a centre-of-mass energy of 13 TeV, using data from the ATLAS detector at the CERN Large Hadron Collider. Data were collected in a special low-luminosity configuration with a minimum-bias trigger and a high-multiplicity track trigger, accumulating integrated luminosities of 151 $\mu$b$^{-1}$ and 8.4 nb$^{-1}$ respectively. The BEC are measured for pairs of like-sign charged particles, each with $|\eta|$ < 2.5, for two kinematic ranges: the first with particle $p_T$ > 100 MeV and the second with particle $p_T$ > 500 MeV. The BEC parameters, characterizing the source radius and particle correlation strength, are investigated as functions of charged-particle multiplicity (up to 300) and average transverse momentum of the pair (up to 1.5 GeV). The double-differential dependence on charged-particle multiplicity and average transverse momentum of the pair is also studied. The BEC radius is found to be independent of the charged-particle multiplicity for high charged-particle multiplicity (above 100), confirming a previous observation at lower energy. This saturation occurs independent of the transverse momentum of the pair.

154 data tables

Comparison of single-ratio two-particle correlation functions, C<sub>2</sub><sup>data</sup>(Q) and C<sub>2</sub><sup>MC</sup>(Q), with the two-particle double-ratio correlation function, R<sub>2</sub>(Q), for the high-multiplicity track (HMT) events using the opposite hemisphere (OHP) like-charge particles pairs reference sample for k<sub>T</sub> - interval 1000 &lt; k<sub>T</sub> &le; 1500&nbsp;MeV.

Comparison of single-ratio two-particle correlation functions, C<sub>2</sub><sup>data</sup>(Q) and C<sub>2</sub><sup>MC</sup>(Q), with the two-particle double-ratio correlation function, R<sub>2</sub>(Q), for the high-multiplicity track (HMT) events using the unlike-charge particle (UCP) pairs reference sample for k<sub>T</sub> - interval 1000 &lt; k<sub>T</sub> &le; 1500&nbsp;MeV.

The Bose-Einstein correlation (BEC) parameter R as a function of n<sub>ch</sub> for MB events using different MC generators in the calculation of R<sub>2</sub>(Q). The uncertainties shown are statistical. The lower panel of each plot shows the ratio of the BEC parameters obtained using EPOS LHC (red circles), Pythia 8 Monash (blue squares) and Herwig++ UE-EE-5 (green triangles) compared with the parameters obtained using Pythia 8 A2. The gray band in the lower panels is the MC systematic uncertainty, obtained as explained in the text.

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Measurement of quark- and gluon-like jet fractions using jet charge in PbPb and pp collisions at 5.02 TeV

The CMS collaboration Sirunyan, Albert M ; Tumasyan, Armen ; Adam, Wolfgang ; et al.
JHEP 07 (2020) 115, 2020.
Inspire Record 1789224 DOI 10.17182/hepdata.88294

The momentum-weighted sum of the electric charges of particles inside a jet, known as jet charge, is sensitive to the electric charge of the particle initiating the parton shower. This paper presents jet charge distributions in $\sqrt{s_\mathrm{NN}} =$ 5.02 TeV lead-lead (PbPb) and proton-proton (pp) collisions recorded with the CMS detector at the LHC. These data correspond to integrated luminosities of 404 $\mu$b$^{-1}$ and 27.4 pb$^{-1}$ for PbPb and pp collisions, respectively. Leveraging the sensitivity of the jet charge to fundamental differences in the electric charges of quarks and gluons, the jet charge distributions from simulated events are used as templates to extract the quark- and gluon-like jet fractions from data. The modification of these jet fractions is examined by comparing pp and PbPb data as a function of the overlap of the colliding Pb nuclei (centrality). This measurement tests the color charge dependence of jet energy loss due to interactions with the quark-gluon plasma. No significant modification between different centrality classes and with respect to pp results is observed in the extracted fractions of quark- and gluon-like jet fractions.

14 data tables

Unfolded jet charge measurements for the $p_{T}$-weighting factor $\kappa = 0.5$ and a minimum track $p_{T}$ of 1 GeV for inclusive jets in pp and PbPb data. The PbPb results are shown for different centrality regions.

The standard deviation of the jet charge distributions with different track $p_{T}$ thresholds and $\kappa$ value of 0.5 for pp collisions and in the various event centrality bins for PbPb collisions compared with the PYTHIA6 prediction.

The standard deviation of the jet charge distributions with different track $p_{T}$ thresholds and $\kappa$ value of 0.3 for pp collisions and in the various event centrality bins for PbPb collisions compared with the PYTHIA6 prediction.

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Jet properties in PbPb and pp collisions at $\sqrt{s_\mathrm{NN}} =$ 5.02 TeV

The CMS collaboration Sirunyan, Albert M ; Tumasyan, Armen ; Adam, Wolfgang ; et al.
JHEP 05 (2018) 006, 2018.
Inspire Record 1658057 DOI 10.17182/hepdata.83196

Modifications of the properties of jets in PbPb collisions, relative to those in pp collisions, are studied at a nucleon-nucleon center-of-mass energy of $\sqrt{s_\mathrm{NN}} =$ 5.02 TeV via correlations of charged particles with the jet axis in relative pseudorapidity ($\Delta \eta$), relative azimuth ($\Delta \phi$), and relative angular distance from the jet axis $\Delta \mathrm{r} = \sqrt{{(\Delta\eta)^{2}+(\Delta\phi)^{2}}}$. This analysis uses data collected with the CMS detector at the LHC, corresponding to integrated luminosities of 404 $\mu$b$^{-1}$ and 27.4 pb$^{-1}$ for PbPb and pp collisions, respectively. Charged particle number densities, jet fragmentation functions, and jet shapes are presented as a function of PbPb collision centrality and charged-particle track transverse momentum, providing a differential description of jet modifications due to interactions with the quark-gluon plasma.

12 data tables

The distribution of jet-correlated charged-particle tracks with $|{\Delta\phi}|<1.0$ as a function of $\Delta\eta$ in pp and PbPb collisions. The PbPb results are shown for different centrality regions.

The difference between the PbPb and pp measurements from Table 1.

The distribution of jet-correlated charged-particle tracks with $|{\Delta\eta}|<1.0$ as a function of $\Delta\phi$ in pp and PbPb collisions. The PbPb results are shown for different centrality regions.

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Observation of correlated azimuthal anisotropy Fourier harmonics in pp and pPb collisions at the LHC

The CMS collaboration Sirunyan, Albert M ; Tumasyan, Armen ; Adam, Wolfgang ; et al.
Phys.Rev.Lett. 120 (2018) 092301, 2018.
Inspire Record 1626103 DOI 10.17182/hepdata.79667

The azimuthal anisotropy Fourier coefficients ($v_n$) in 8.16 TeV pPb data are extracted via long-range two-particle correlations as a function of event multiplicity and compared to corresponding results in pp and PbPb collisions. Using a four-particle cumulant technique, $v_n$ correlations are measured for the first time in pp and pPb collisions. The $v_2$ and $v_4$ coefficients are found to be positively correlated in all collision systems. For high multiplicity pPb collisions an anticorrelation of $v_2$ and $v_3$ is observed, with a similar correlation strength as in PbPb data at the same multiplicity. The new correlation results strengthen the case for a common origin of the collectivity seen in pPb and PbPb collisions in the measured multiplicity range.

9 data tables

The $v_{n}$ result from 2-particle correlation as a function of multiplicity ($N_{trk}^{offline}$) in PbPb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV. Results after low-multiplicity subtraction are denoted as $v_{n}^{sub}$.

The $v_{n}$ result from 2-particle correlation as a function of multiplicity ($N_{trk}^{offline}$) in pPb collisions at $\sqrt{s_{NN}}$ = 8.16 TeV. Results after low-multiplicity subtraction are denoted as $v_{n}^{sub}$.

The $v_{4}$ result from 2-particle correlation as a function of multiplicity ($N_{trk}^{offline}$) in pp collisions at $\sqrt{s}$ = 13.00 TeV. Results after low-multiplicity subtraction are denoted as $v_{4}^{sub}$.

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Charged-particle multiplicity distributions over a wide pseudorapidity range in proton-proton collisions at $\mathbf{\sqrt{s}=}$ 0.9, 7 and 8 TeV

The ALICE collaboration Acharya, S. ; Adamová, D. ; Adolfsson, J. ; et al.
Eur.Phys.J.C 77 (2017) 852, 2017.
Inspire Record 1614477 DOI 10.17182/hepdata.78802

We present the charged-particle multiplicity distributions over a wide pseudorapidity range ($-3.4<\eta<5.0$) for pp collisions at $\sqrt{s}=$ 0.9, 7, and 8 TeV at the LHC. Results are based on information from the Silicon Pixel Detector and the Forward Multiplicity Detector of ALICE, extending the pseudorapidity coverage of the earlier publications and the high-multiplicity reach. The measurements are compared to results from the CMS experiment and to PYTHIA, PHOJET and EPOS LHC event generators, as well as IP-Glasma calculations.

90 data tables

Multiplicity distribution in the pseudorapidity region -2.0 to 2.0 for NSD collisions at a centre-of-mass energy of 900 GeV.

Multiplicity distribution in the pseudorapidity region -2.4 to 2.4 for NSD collisions at a centre-of-mass energy of 900 GeV.

Multiplicity distribution in the pseudorapidity region -3.0 to 3.0 for NSD collisions at a centre-of-mass energy of 900 GeV.

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Measurement of multi-particle azimuthal correlations in $pp$, $p$+Pb and low-multiplicity Pb+Pb collisions with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
Eur.Phys.J.C 77 (2017) 428, 2017.
Inspire Record 1599077 DOI 10.17182/hepdata.77996

Multi-particle cumulants and corresponding Fourier harmonics are measured for azimuthal angle distributions of charged particles in $pp$ collisions at $\sqrt{s}$ = 5.02 and 13 TeV and in $p$+Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV, and compared to the results obtained for low-multiplicity Pb+Pb collisions at $\sqrt{s_{NN}}$ = 2.76 TeV. These measurements aim to assess the collective nature of particle production. The measurements of multi-particle cumulants confirm the evidence for collective phenomena in $p$+Pb and low-multiplicity Pb+Pb collisions. On the other hand, the $pp$ results for four-particle cumulants do not demonstrate collective behaviour, indicating that they may be biased by contributions from non-flow correlations. A comparison of multi-particle cumulants and derived Fourier harmonics across different collision systems is presented as a function of the charged-particle multiplicity. For a given multiplicity, the measured Fourier harmonics are largest in Pb+Pb, smaller in $p$+Pb and smallest in $pp$ collisions. The $pp$ results show no dependence on the collision energy, nor on the multiplicity.

95 data tables

$c_2\{4\}$ cumulants for reference particles with 0.3 $< p_T <$ 3.0 GeV selected according to $M_{ref}$ (EvSel_$M_{ref}$) for pp collisions at $\sqrt{s}$= 5.02 TeV.

$c_2\{4\}$ cumulants for reference particles with 0.3 $< p_T <$ 3.0 GeV selected according to $M_{ref}$ (EvSel_$M_{ref}$) for pp collisions at $\sqrt{s}$= 13 TeV.

$c_2\{4\}$ cumulants for reference particles with 0.3 $< p_T <$ 3.0 GeV selected according to $M_{ref}$ (EvSel_$M_{ref}$) for pPb collisions at $\sqrt{ s_{NN} }$= 5.02 TeV.

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Measurement of charged-particle distributions sensitive to the underlying event in $\sqrt{s} = 13$ TeV proton-proton collisions with the ATLAS detector at the LHC

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
JHEP 03 (2017) 157, 2017.
Inspire Record 1509919 DOI 10.17182/hepdata.76730

We present charged-particle distributions sensitive to the underlying event, measured by the ATLAS detector in proton-proton collisions at a centre-of-mass energy of 13 TeV, in low-luminosity Large Hadron Collider fills corresponding to an integrated luminosity of 1.6 nb$^{-1}$. The distributions were constructed using charged particles with absolute pseudorapidity less than 2.5 and with transverse momentum greater than 500 MeV, in events with at least one such charged particle with transverse momentum above 1 GeV. These distributions characterise the angular distribution of energy and particle flows with respect to the charged particle with highest transverse momentum, as a function of both that momentum and of charged-particle multiplicity. The results have been corrected for detector effects and are compared to the predictions of various Monte Carlo event generators, experimentally establishing the level of underlying-event activity at LHC Run 2 energies and providing inputs for the development of event generator modelling. The current models in use for UE modelling typically describe this data to 5% accuracy, compared with data uncertainties of less than 1%.

32 data tables

Unit-normalised distribution of the transverse momentum of the leading charged-particle $p_\mathrm{T}^\mathrm{lead}$ > 1 GeV.

Mean values of charged-particle multiplicity $n_\mathrm{ch}$ as a function of leading charged-particle $p_\mathrm{T}$ in the trans-min azimuthal region.

Mean values of charged-particle multiplicity $n_\mathrm{ch}$ as a function of leading charged-particle $p_\mathrm{T}$ in the trans-max azimuthal region.

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Version 2
Charged-particle nuclear modification factors in PbPb and pPb collisions at sqrt(s[NN)]=5.02 TeV

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
JHEP 04 (2017) 039, 2017.
Inspire Record 1496050 DOI 10.17182/hepdata.77101

The spectra of charged particles produced within the pseudorapidity window abs(eta) < 1 at sqrt(s[NN]) = 5.02 TeV are measured using 404 inverse microbarns of PbPb and 27.4 inverse picobarns of pp data collected by the CMS detector at the LHC in 2015. The spectra are presented over the transverse momentum ranges spanning 0.5 < pt < 400 GeV in pp and 0.7 < pt < 400 GeV in PbPb collisions. The corresponding nuclear modification factor, R[AA], is measured in bins of collision centrality. The R[AA] in the 5% most central collisions shows a maximal suppression by a factor of 7-8 in the pt region of 6-9 GeV. This dip is followed by an increase, which continues up to the highest pt measured, and approaches unity in the vicinity of pt = 200 GeV. The R[AA] is compared to theoretical predictions and earlier experimental results at lower collision energies. The newly measured pp spectrum is combined with the pPb spectrum previously published by the CMS Collaboration to construct the pPb nuclear modification factor, R[pA], up to 120 GeV. For pt > 20 GeV, R[pA] exhibits weak momentum dependence and shows a moderate enhancement above unity.

32 data tables

Charged-particle per-event yields measured in 0-5% PbPb centrality class.

Charged-particle per-event yields measured in 0-5% PbPb centrality class.

Charged-particle per-event yields measured in 5-10% PbPb centrality class.

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Evidence for collectivity in pp collisions at the LHC

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Phys.Lett.B 765 (2017) 193-220, 2017.
Inspire Record 1471287 DOI 10.17182/hepdata.76506

Measurements of two- and multi-particle angular correlations in pp collisions at sqrt(s) = 5, 7, and 13 TeV are presented as a function of charged-particle multiplicity. The data, corresponding to integrated luminosities of 1.0 inverse picobarn (5 TeV), 6.2 inverse picobarns (7 TeV), and 0.7 inverse picobarns (13 TeV), were collected using the CMS detector at the LHC. The second-order (v[2]) and third-order (v[3]) azimuthal anisotropy harmonics of unidentified charged particles, as well as v[2] of K0 short and Lambda/anti-Lambda particles, are extracted from long-range two-particle correlations as functions of particle multiplicity and transverse momentum. For high-multiplicity pp events, a mass ordering is observed for the v[2] values of charged hadrons (mostly pions), K0 short, and Lambda/anti-Lambda, with lighter particle species exhibiting a stronger azimuthal anisotropy signal below pt of about 2 GeV/c. For 13 TeV data, the v[2] signals are also extracted from four- and six-particle correlations for the first time in pp collisions, with comparable magnitude to those from two-particle correlations. These observations are similar to those seen in pPb and PbPb collisions, and support the interpretation of a collective origin for the observed long-range correlations in high-multiplicity pp collisions.

34 data tables

The second-order Fourier coefficients, $V_{2\Delta}(2, |\Delta\eta| > 2)$, as a function of $N_{offline}^{trk}$ for charged particles.

The second-order Fourier coefficients, $V_{2\Delta}(2, |\Delta\eta| > 2)$, as a function of $N_{offline}^{trk}$ for charged particles, after correcting for back-to-back jet correlations, estimated from the 10 $\leq$ $N_{offline}^{trk}$ < 20 range.

The second-order Fourier coefficients, $V_{3\Delta}(2, |\Delta\eta| > 2)$, as a function of $N_{offline}^{trk}$ for charged particles.

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