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Physics
Letters
B
www.elsevier.com/locate/physletb
Centrality
dependence
of
the
pseudorapidity
density
distribution
for
charged
particles
in
Pb–Pb
collisions
at
√
s
NN=
5.02 TeV
.
ALICE
Collaboration
a
r
t
i
c
l
e
i
n
f
o
a
b
s
t
r
a
c
t
Articlehistory:
Received 9 January 2017
Received in revised form 19 June 2017 Accepted 9 July 2017
Available online 14 July 2017 Editor: L. Rolandi
We present the charged-particle pseudorapidity density in Pb–Pb collisions at √sNN=5.02 TeV in centralityclassesmeasuredbyALICE.Themeasurementcoversawidepseudorapidityrangefrom−3.5 to5,whichissufficientforreliableestimatesofthetotalnumberofchargedparticlesproducedinthe collisions.Forthemostcentral(0–5%)collisionswefind21400±1300,whileforthemostperipheral (80–90%)we find230±38.Thiscorresponds toan increaseof(27±4)% over theresults at√sNN= 2.76 TeV previouslyreportedbyALICE.Theenergydependenceofthetotalnumberofchargedparticles produced inheavy-ioncollisions is foundtoobey amodifiedpower-lawlikebehaviour. The charged-particlepseudorapiditydensityofthemostcentralcollisionsiscomparedtomodelcalculations—none ofwhichfullydescribes themeasureddistribution.Wealsopresentanestimateoftherapiditydensity ofchargedparticles.Thewidth ofthatdistributionisfoundtoexhibitaremarkableproportionalityto thebeamrapidity,independentofthecollisionenergyfromthetopSPStoLHCenergies.
©2017TheAuthor(s).PublishedbyElsevierB.V.ThisisanopenaccessarticleundertheCCBYlicense (http://creativecommons.org/licenses/by/4.0/).FundedbySCOAP3.
1. Introduction
Inultra-relativisticheavy-ioncollisions a denseandhot phase of nuclear matter is created [1–4]. This phase of QCD matter is consideredtobe aplasmaofstronglyinteractingquarksand glu-ons and is therefore labelled the sQGP [5]. The multiplicity of primary, charged particles produced in heavy-ion collisions is a keyobservabletocharacterisethepropertiesofthemattercreated inthese collisions [6]. The studyof theprimary charged-particle pseudorapiditydensity(dNch
/
dη
) overa wide pseudorapidity(η
)rangeanditsdependenceoncollidingsystem,centre-of-mass en-ergy,andcollision geometryisimportantto understandthe rela-tivecontributionstoparticleproductionfromhardscatteringsand softprocesses,andmayprovideinsightintothepartonicstructure oftheinteractingnuclei.
Wehave previouslyreportedmeasurements on primary charged-particlepseudorapiditydensitiesoverawidepseudorapidityrange inPb–Pbcollisions atthecentre-of-mass energypernucleonpair
√
sNN
=
2.
76 TeV[7].InthisLetter,westudythesedistributionsinthepseudorapidityintervalfrom
−
3.
5 to5 atacollisionenergyof√
sNN
=
5.
02 TeV asa functionofthe centrality.Pseudorapidityisdefinedas
η
≡ −
log(
tan(ϑ/
2))
,whereϑ
istheanglebetweenthe charged-particle trajectory andthebeam axis(z-axis).Nuclei are extendedobjects,andtheircollisionscanbecharacterisedby cen-trality— the experimental proxy forthe un-measurable distanceE-mailaddress:alice-publications@cern.ch.
between the centres of the colliding nuclei (impact parameter). A primary particle is a particle with a mean proper lifetime
τ
larger than 1 cm
/
c, which is either a) produced directly in the interaction, or b) from decays of particles withτ
smaller than 1 cm/
c,restrictedtodecaychainsleadingtotheinteraction[8].In this Letter, all quantities reported are forprimary charged parti-cles,thoughwewillomit“primary”forbrevity.Withthe largepseudorapidity coverage available inALICE, we can reliably estimate, for all centrality classes, the total number ofchargedparticles produced inthecollisions. We thereforealso presentthefirstmeasurement ofthetotalcharged-particle multi-plicityinPb–Pbcollisions at
√
sNN=
5.
02 TeV asafunctionofthenumberofnucleonsparticipatinginthecollisions(Npart).
Finally, we transform the measured dNch
/
dη
distribution forthe5%mostcentralcollisionsintocharged-particlerapiditydensity (dNch
/
d y),andweexaminethecentre-of-massenergydependenceof the width of that distribution. The rapidity ( y) of a particle withenergyE andmomentumcomponentpzalongthebeamaxis
isdefinedas y
≡
12log(
[
E+
pz]/[
E−
pz])
.Thecomparisonofthewidth of the dNch
/
d y at different collision energies provides aninsight intotheconstraints onthe overall productionmechanism ofchargedparticles.
2. Experimentalsetup
A detailed description of ALICE and its performance can be found elsewhere [9,10]. In the following, we briefly describe the detectorsrelevanttothisanalysis.
http://dx.doi.org/10.1016/j.physletb.2017.07.017
0370-2693/©2017 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP3.
TheSiliconPixelDetector(SPD),theinnermostpartoftheInner TrackingSystem(ITS), consistsoftwo cylindricallayers ofhybrid siliconpixelassembliescovering
|
η
|
<
2 and|
η
|
<
1.
4 fortheinner andouterlayers,respectively.Combinationsofhitsoneachofthe twolayers consistent withtracksoriginatingfromtheinteraction pointformtracklets.TheForwardMultiplicityDetector(FMD)isasiliconstrip detec-torwhich,recordstheenergydepositedbyparticlestraversingthe it.Thedetectorcoversthepseudorapidityregions
−
3.
5<
η
<
−
1.
8 and1.
8<
η
<
5,andhasalmostfullcoverageinazimuth(ϕ
),and highgranularityintheradial(η
)direction.The third detector system used in this analysis is the V0. It consistsoftwosub-detectors:V0-AandV0-C coveringthe pseudo-rapidity regions 2
.
8<
η
<
5.
1 and−
3.
7<
η
<
−
1.
7,respectively, eachmadeup ofscintillatortileswithatiming resolution<
1 ns. The fast signals from eitherof V0-A or V0-C are combined in a programmable logic to form a trigger signal and to reject back-groundevents.Furthermore,the combined pulseheight signal of bothsub-detectors formsthebasis fortheclassificationofevents intodifferentcentralityclasses[11].The Zero-Degree Calorimeter (ZDC) measures the energy of spectator (non-interacting) nucleons with two components: one measures protons and the other measures neutrons. The ZDC is locatedatabout112.5 mfromtheinteractionpointonbothsides ofthe experiment [9]. The ZDCalsoprovides timing information usedtoselectcollisionsintheoff-linedataprocessing.
3. Datasampleandanalysismethod
Theresults presentedherearebasedon datacollected by AL-ICEin2015during thePb–Pbcollision runofthe LHCat
√
sNN=
5
.
02 TeV. About 100000 eventswitha minimumbias trigger re-quirement[12] were analysed inthe centralityrange from0% to 90%.TheminimumbiastriggerforPb–PbcollisionsinALICE,which definesthe so-called visiblecross-section, is definedas a coinci-dencebetweentheA(z>
0)andC(z<
0)sidesoftheV0detector. Thestandard ALICEeventselection[13] andcentrality estima-torbasedontheV0–amplitude[11]areusedinthisanalysis.The eventselection consistsof: exclusionof backgroundevents using the timing information fromthe ZDC andV0 detectors; verifica-tionofthetriggerconditions;andareconstructed positionofthe collision.Asdiscussedelsewhere[11],the90–100%centralityclass hassubstantialcontributionsfromQEDprocessesandistherefore notincludedintheresultspresentedhere.The measurement ofthe charged-particle pseudorapidity den-sityat mid-rapidity (
|
η
|
<
2) is obtainedfroma tracklet analysis usingthetwolayersoftheSPD.Theanalysismethodusedis iden-ticaltowhat haspreviously beenpresented [12,14,15]. Notethat noattemptismadetocorrectforknowndeficiencies,suchas devi-ationsinthenumberofstrangeparticlesortransversemomentum (pT)distributionscomparedtoexperimentalmeasurements[11,16, 17], in the eventgenerators used to obtain the corrections from simulations (e.g.,HIJING). It isfound, through simulationstudies, thattrackletreconstructionfirstandforemostdependsonthelocal hit density andonly weakly on particle mix andtransverse mo-mentum.Forexample,thedeficitofstrangeparticlesintheevent generatoreffectstheresultbylessthan2%.Sincetheevent genera-torsgenerally,afterdetectorsimulation,producealocalhitdensity thatisconsistentwithwhatisobservedindata,weobservea cor-respondencebetweenthetrackletsamplesofbothsimulationsand data.Ontheother hand,changingthenumberoftracklets corre-spondingtostrangeparticlesapostioritomatchthemeasured rel-ativeyieldsdramaticallybiasesthesimulatedtrackletsampleaway fromthemeasured,thusentailingsystematicuncertaintiesthatare beyondtheeffect oftheknown eventgeneratordeficiencies, andFig. 1. [Colour
online.]
Charged-particle pseudorapidity density for ten centrality classes over a broad ηrange in Pb–Pb collisions at √sNN=5.02 TeV. Boxes aroundthe points reflect the total uncorrelated systematic uncertainties, while the filled squares on the right reflect the correlated systematic uncertainty (evaluated at
η=0). Statistical errors are generally insignificant and smaller than the markers. Also shown is the reflection of the 3.5 <η<5 values around η=0 (open circles). The line corresponds to fits of the difference between two Gaussians centred at
η=0 ( fGG) [7]to the data.
assuchdonotimprovetheaccuracyofthemeasurements.Instead, variationsontheeventgeneratorsareusedtoestimatethe system-aticuncertaintiesasdetailedelsewhere
[12,14,15]
.Intheforwardregions (
−
3.
5<
η
<
−
1.
8 and 1.
8<
η
<
5),the measurement isprovidedby theanalysisofthedepositedenergy signal intheFMD.The analysismethodusedisidenticaltowhat haspreviouslybeenpresented[7,14]:a statisticalapproachto cal-culatetheinclusivenumberofchargedparticles;andadata-driven correction — derived from previous satellite-main collisions — to removethelargebackgroundfromsecondaryparticles.4. Systematicuncertainties
For the measurements at mid-rapidity the sources and de-pendencies ofthesystematicuncertaintiesare detailedelsewhere
[7,12,15]. The magnitude of the systematic uncertainties is un-changed withrespecttoprevious results,andamounts to2
.
6% atη
=
0 and 2.
9% atη
=
2,mostofwhichiscorrelatedover|
η
|
<
2, andlargelyindependentofcentrality.Thesystematicuncertaintyontheforwardanalysisisevaluated usingthesametechnique asforpreviousresults
[7]
.Wefindthat theuncertaintyisuncorrelatedacrossη
anthatitamountsto6.
9% forη
>
3.
5 and6.
4% elsewherewithintheforwardregions.The systematic uncertainty on dNch
/
dη
due to the centralityclassdefinitionisestimatedas0
.
6% forthemostcentraland9.
5% for the most peripheral class [15]. The uncertainty is estimated by usingalternative centrality definitions basedon SPD hit mul-tiplicitiesandbyvaryingthefractionofthevisiblehadronic cross-section. The 80–90% centrality class has some residual contam-ination from electromagnetic processes detailed elsewhere [11], which givesrisetoa 4% additionalsystematicuncertainty onthe measurements.In summary,thetotal systematicuncertaintyvariesfrom2
.
6% atmid-rapidityinthemostcentralcollisionsto12.
4% atthevery forwardrapiditiesforthemostperipheralcollisions.5. Results
Fig. 1 presents the charged-particle pseudorapidity densityas a function of pseudorapidity for ten centralityclasses. The mea-surements from the SPD and FMD are combined in regions of overlap (1
.
8<
|
η
|
<
2) between the two detectors by taking the weighted average using the non-shared uncertainties as weights. Finally,basedonthe symmetryofthecollisionsystem, theresult issymmetrisedaroundη
=
0,andextendedintothenon-measuredFig. 2. [Colour
online.] Total number of charged particles as a function of the mean
number of participating nucleons [11]. The total charged-particle multiplicity is given as the integral over dNch/dηover the measured region (−3.5 <η<5) and extrapolations from fitted functions in the unmeasured regions. The contribution from unmeasured ηregions amounts to ≈30% of the total number of charged particles. The uncertainty on the extrapolation to the unmeasured pseudorapidity region is smaller than the size of the markers. The contribution to the systematic uncertainties from the centrality determination and electromagnetic processes are vanishing compared to the contribution from the largest differences between the fitted functions. A function inspired by factorisation[18]is fitted to the data, and the best fit yields a=51.5 ±7.3, b=0.16 ±0.05.region
−
5<
η
<
−
3.
5 byreflectingthe3.
5<
η
<
5 valuesaroundη
=
0. Complementing resultpreviously reported atmid-rapidity[15],wefind dNch
/
dη
|
|η|<0.5=
17.
52±
0.
05(
stat)
±
1.
84(
sys)
andNpart
=
7.
3±
0.
1 inthe80–90%centralityclass.Themeasured distributions arefittedwithfourfunctions fGG,
fP, fT,and fB [7],whichare the differenceof twoGaussian
dis-tributions centredat
η
=
0; aparametrisation proposed by PHO-BOS[18];atrapezoidalform;andaplateauconnectedtoGaussian tails, respectively. To extract the total number of charged parti-cles,wecalculatetheintegralanduncertaintyfromthedatainthe measured region and use the integrals of the fitted functionsin theunmeasuredregions uptothe beamrapidity±
ybeam= ±
8.
6.Asforthepreviousmeasurementsat
√
sNN=
5.
02 TeV,thecentralvalue inthe unmeasuredregions (
−
8.
6<
η
<
−
3.
5 and 5<
η
<
8
.
6)istakenfromthefitofthefunction fT,whiletheuncertaintyisevaluatedasthelargestdifferencebetweenthe fittedfunctions scaled by 1
/
√
3 [7,14]. The total charged-particle multiplicity is shownin Fig. 2versus the meannumber of participating nucle-ons (Npart) estimated from a Glauber calculation [11,15]. Afterremoving correlated systematic uncertainties, we observe an in-creaseinthe totalnumberofchargedparticles of
(
27±
4)
% with respectto the measurements at√
sNN=
2.
76 TeV[7] forallcen-trality classes. The line shown in Fig. 2 corresponds to a fit of a function inspired by factorisation [18]. The function illustrates scalingby numberofparticipantpairs,witha smallperturbation proportional to the cubic rootof the number of participants. As the number of nucleon–nucleon collisions (Ncoll) scales roughly
likethesquareofthenumberofparticipantsNcoll
≈
N2part[19],weseenoindication of scalingby numberofnucleon–nucleon colli-sions.The observed total Nch dependenceon
Npartprovides noevidenceofanysignificantincreaseinthenumberofhard scatter-ingsbetweentheparticipatingnucleonsandpartons.
In
Fig. 3
,wecomparethecharged-particle pseudorapidity den-sity for the 0–5% most central collisions to three models: HI-JING [20]; EPOS–LHC [21]; and KLN [22,23], also for the 0–5% mostcentral,exceptforKLNwhichisshownforthe0–6% central-ityclass.TwoversionsofHIJINGareused:version 1.383,withjet quenchingdisabled,shadowing enabled, anda hard pT cut-offof2.3 GeV;andthenewerversion 2.1[24].Botharetwo-component models witha softand hard sector definedby a pT cut-off
sep-arating the two. In the 2.1 implementation, HIJING uses an up-graded parametrisation of the nuclear parton distribution
func-Fig. 3. [Colour
online.] Comparison of dN
ch/dη in the 0–5% (0–6% for KLN) most central collisions of two versions of HIJING, KLN, and EPOS–LHC model calculations to the measured distribution.Fig. 4. [Colour
online.] Total number of charged particles as a function of
√sNNforthe most central collisions at AGS (0–5% Au–Au)[25,26], SPS (0–5% Pb–Pb)[27,28], RHIC (0–5% and 0–6% Au–Au)[18,29,30], and LHC (0–5% Pb–Pb) [14]. The dotted, dashed, and full lines are extrapolations from fits to lower energy results [14], while the dash-dotted line is a fit over all energies, including √sNN=5.02 TeV.
tions.Thisresultsinalargercrosssectionforsoftprocessesanda smallercrosssectionforjetproduction.TheKLN modelisbasedon Colour-Glass-Condensate initial conditions, while EPOS-LHC uses so-called parton-ladders which hadronise in a medium. While noneofthethreemodels describethemeasured charged-particle pseudorapiditydensityoverthefull pseudorapidityrange,we ob-serve some differences: HIJING 1.383 over-predicts the charged-particle production especially away from
η
≈
0; EPOS–LHC and HIJING 2.1 consistently under-predict the charge-particle produc-tion; whereas KLN, EPOS–LHC, and HIJING 2.1 give a shape rea-sonably close to the observed distribution. Not shown in Fig. 3, forbothHIJING 1.383andEPOS–LHC,theseobservationsholdover allcentralityclassesi.e.,HIJING 1.383consistentlyproducesfartoo manyparticlesawayfrommid-rapidityandEPOS–LHCconsistently under-predicts the charged-particle yield over the fullη
range. Thesetrends becomeincreasingly morepronouncedformore pe-ripheralcollisions.Fig. 4 showsthe total number of charged particles produced in themostcentral heavy-ion collisions asa functionof the col-lisionenergy,ranging from
√
sNN=
2.
6 GeV to 5.
02 TeV [14].Thedotted,dashed,andfull-drawnlinesinthefigurerepresent extrap-olationsfromlowerenergyresultstothecurrenttopLHCenergyof
√
sNN
=
5.
02 TeV.Noneofthesepredictionsfullydescribethedata.A refitofthesimplemodelofalogarithmic-dampenedpower-law inthesquarecollisionenergy(s)includingfromthelowesttothe highestenergyresults,shownasthedash-dottedline, does accu-ratelydescribethetotalnumberofchargedparticlesatallavailable energies.
Fig. 5. [Colour online.] Estimate of dNch/d y in the most central (0–5%) Pb–Pb collisions at √sNN=5.02 TeV. Also shown are the Landau–Wong [31], Landau–
Carruthers [32], Gaussian, and double-Gaussian distributions.
Fig. 6. [Colour
online.] Scaling behaviour as a function
√sNN of the width of thecharged-particle or -pion rapidity-density distribution with respect to the Landau– Carruthers width (top) and rapidity range (bottom). Charged-pion points from AGS and SPS are adapted from the literature [33], while the PHOBOS (filled crosses) [34] and BRAHMS (open crosses) [30]charged-hadron points are translated from the cor-responding dNch/dηresults.
We can calculate the Jacobian transform from
η
to rapidity y by assuming the same transverse momentum distribution of (anti-)protons, and charged kaons andpions, andthe same par-ticleratios inPb–Pb collisions at√
sNN=
5.
02 TeV as in√
sNN=
2
.
76 TeV.TheresultispresentedinFig. 5
forthe0–5%most cen-tral collisions. The effect on the Jacobian fromthe changeof pTspectraandparticleratioswhenincreasingthecollisionenergyby almosta factortwoisevaluated usingtheEPOS–LHC model[21]. Itisfound,thattheeffectisatmost3‰onbothdNch
/
d y and y —muchsmallerthanthesystematicuncertaintyand
η
resolutionof theanalysis.Fig. 5
alsoshowstheexpectedcharged-particle rapid-itydensities from the Landau–Carruthers [32] andLandau–Wong[31] models,both assuming Landauhydrodynamics i.e., basedon areactionscenariowithfullstoppingofthereactionpartnersand asubsequentthermodynamic evolution.Themeasurements, how-ever,areseentobeconsistentwithaGaussiandistributionwitha widthof4
.
12±
0.
10,much widerthan thewidth expectedfrom thetwomodels.Abestparameterfitofthesumoftwo Gaussian distributionswithmeanssymmetricaroundy=
0,is indistinguish-ablefromthesingleGaussiancase.In the top part of Fig. 6 we compare the widths of the charged-particle or -pion rapidity density distribution extracted frommeasurements tothe expectedwidth
σ
2L-C
=
log(
√
sNN
/
2mp)
from Landau–Carruthers, where mp is the proton mass, at
colli-sion energies ranging from2
.
6 GeV up to 5.
02 TeV. An increase of≈
7% ofσdN
X/d y/
σ
L-C is seen from the√
sNN
=
2.
76 TeVAL-ICE measurements [14]. The full evolution is consistent with an almost linearriseasa function oflog
√
sNN fromthe topSPSen-ergyat
√
sNN=
17.
3 GeV. Itcanbe shown[35] thatthe widthofthe rapidity-density distribution in Landau hydrodynamics scales as
σdN
X/d y∝
1/(
1−
c2
s
)
,wherecsisthespeedofsoundinthemat-ter.The lifetimeofthe systemscales inverselywithcs,andgiven
that the measured widthis larger than the predicted by Landau hydrodynamics, it is an indication that, given the considerations above,thelifetimeisshorterthansuggested.
In the bottom part of Fig. 6 we compare the width of the dNch
/
d y distributiontotheavailable rapidityrange(2 ybeam). Weobserve no dependence ofthis ratio from
√
sNN=
17.
3 GeV andupward, indicating that the available phase–space constrains the width of that distribution. The charged-hadron measurements at RHIC (crosses) from the BRAHMS [30] and PHOBOS [34] mea-surements ofdNch
/
dη
areconverted to dNch/
d y usingthe samemethod as applied to the ALICE data. Previously, charged-pion measurements fromBRAHMShavebeenreported[33].Thesedata arenotincludedbecauseare-evaluationusingRHICRun-4Au–Au datahasnotbeenfinalised
[36]
.Fromtheobservedsp scalingofthecharged-particle pseudora-pidity densityatmid-rapidity
[15]
weexpect a20% increaseover√
sNN
=
2.
76 TeV in thelevelof dNch/
dη
|
|η|<0.5 andfromtheex-tractedwidthofdNch
/
d y weobserveanadditional7%,consistentwiththeincreaseof27% over
√
sNN=
2.
76 TeV inthetotalnumberofchargedparticlesproducedin
√
sNN=
5.
02 TeV collisions. 6. ConclusionsThecharged-particlepseudorapiditydensityismeasuredinPb– Pb collisions at
√
sNN=
5.
02 TeV over the psuedorapidity range−
3.
5<
η
<
5. The totalnumber ofchargedparticles produced is determined owing to the large pseudorapidity acceptance of AL-ICE.Thelatterincreasesbytwoordersofmagnitudefromthemost peripheralto themostcentralcollisions andscales approximately with the number of participating nucleons. The increase in the totalnumberofchargedparticlesrelativeto√
sNN=
2.
76 TeV ises-timated tobe
(
27±
4)
%. Thecharged-particle rapidity densityfor themostcentralcollisions isextracted, andthewidthofthat dis-tribution is compared to predictionsfrom theLandau–Carruthers andLandau–Wonghydrodynamicmodels.Itisfoundthatthe mea-suredcharged-particlerapiditydensitybecomesincreasinglywider as a function of collision energy than predicted by Landau hy-drodynamics. The width of the charged-particle rapidity density is seen to scale with the beam rapidity, which implies that the available phase space determines the longitudinal extend of the charged-particle production.Thephase spacedominancestarts at thetopSPSenergyandpersistfortwo ordersofmagnitudeupto thetopLHCenergy.Acknowledgements
The ALICECollaboration would like to thank all its engineers andtechniciansfortheirinvaluablecontributionstothe construc-tion of the experiment and the CERN accelerator teams for the outstanding performance of the LHC complex. The ALICE Collab-oration gratefully acknowledges the resources and support pro-videdbyallGridcentresandtheWorldwideLHCComputingGrid (WLCG) collaboration. The ALICE Collaboration acknowledges the following fundingagenciesfortheir supportin buildingand run-ningthe ALICEdetector:A.I. AlikhanyanNationalScience Labora-tory(YerevanPhysicsInstitute)Foundation (ANSL),State Commit-teeofScienceandWorldFederationofScientists(WFS),Armenia; Austrian Academyof SciencesandNationalstiftung fürForschung, Technologie und Entwicklung, Austria; Conselho Nacionalde De-senvolvimento Científico e Tecnológico (CNPq), Universidade Fed-eral do Rio Grande do Sul (UFRGS), Financiadora de Estudos e Projetos (Finep) and Fundação de Amparo à Pesquisa do Estado
deSãoPaulo(FAPESP),Brazil;MinistryofScience&Technologyof China(MSTC),NationalNaturalScienceFoundationofChina(NSFC) andMinistryofEducationofChina(MOEC),China;Ministryof Sci-ence,EducationandSportandCroatianScienceFoundation, Croa-tia;MinistryofEducation,YouthandSportsoftheCzechRepublic, Czech Republic; The Danish Council for Independent Research– NaturalSciences,theCarlsbergFoundationandDanishNational Re-search Foundation (DNRF), Denmark;Helsinki Institute ofPhysics (HIP),Finland;Commissariatàl’EnergieAtomique(CEA)and Insti-tut Nationalde Physique Nucléaire etde Physique des Particules (IN2P3)andCentre National de laRecherche Scientifique (CNRS), France; Bundesministerium für Bildung, Wissenschaft, Forschung undTechnologie(BMBF)and GSI Helmholtzzentrumfür Schweri-onenforschung GmbH, Germany; Ministry of Education, Research andReligiousAffairs,Greece;NationalResearch,Developmentand Innovation Office, Hungary; Department of Atomic Energy, Gov-ernment of India (DAE) and Council of Scientific and Industrial Research (CSIR), New Delhi, India; Indonesian Institute of Sci-ence,Indonesia;CentroFermi- Museo StoricodellaFisica e Cen-troStudi e Ricerche EnricoFermi andIstitutoNazionale di Fisica Nucleare(INFN), Italy; Institute forInnovative Science and Tech-nology, Nagasaki Institute of Applied Science (IIST), Japan Soci-ety for the Promotion of Science (JSPS) KAKENHI and Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan;Consejo Nacional de Ciencia y Tecnología (CONA-CYT), through Fondo de Cooperación Internacional en Ciencia y Tecnología(FONCICYT)andDirecciónGeneralde Asuntosdel Per-sonal Academico (DGAPA), Mexico; Nationaal instituut voor sub-atomaire fysica (Nikhef), Netherlands; The Research Council of Norway,Norway;CommissiononScienceandTechnologyfor Sus-tainableDevelopmentintheSouth(COMSATS),Pakistan;Pontificia UniversidadCatólicadelPerú,Peru;MinistryofScienceandHigher EducationandNationalScience Centre,Poland;Korea Institute of ScienceandTechnology Information andNationalResearch Foun-dation of Korea (NRF), Republic of Korea; Ministry of Education andScientific Research,InstituteofAtomic PhysicsandRomanian National Agency for Science, Technology and Innovation, Roma-nia;JointInstituteforNuclearResearch(JINR),Ministryof Educa-tionandScienceoftheRussian FederationandNationalResearch CentreKurchatovInstitute, Russia;MinistryofEducation,Science, ResearchandSportoftheSlovak Republic, Slovakia; National Re-search Foundation of South Africa, South Africa; Centrode Apli-cacionesTecnológicasyDesarrolloNuclear(CEADEN),Cubaenergía, Cuba, Ministerio de Ciencia e Innovacion and Centro de Investi-gacionesEnergéticas, Medioambientales y Tecnológicas (CIEMAT), Spain;SwedishResearchCouncil(VR)andKnut&AliceWallenberg Foundation(KAW),Sweden;EuropeanOrganizationforNuclear Re-search,Switzerland;NationalScienceandTechnologyDevelopment Agency(NSDTA),SuranareeUniversityofTechnology(SUT)and Of-fice of the Higher Education Commission under NRU project of Thailand,Thailand;TurkishAtomicEnergyAgency(TAEK), Turkey; National Academy of Sciences of Ukraine, Ukraine; Science and TechnologyFacilitiesCouncil(STFC),UnitedKingdom;National Sci-enceFoundationoftheUnitedStatesofAmerica(NSF)andUnited StatesDepartmentofEnergy, Office ofNuclear Physics(DOE NP), UnitedStatesofAmerica.
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