J/ψ production as a function of charged-particle multiplicity in p-Pb collisions at √sNN = 8.16 TeV
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J/ψ p oduc ion as a unc ion o cha ged-pa icle mul iplici y in p-Pb collisions a √sNN =
8.16 TeV
© 2020 CERN
Published e sion
ALICE collabo a ion
ALICE collabo a ion. (2020). J/ψ p oduc ion as a unc ion o cha ged-pa icle mul iplici y in p-Pb
collisions a √sNN = 8.16 TeV. Jou nal o High Ene gy Physics, 2020(10), A icle 162.
h ps://doi.o g/10.1007/JHEP09(2020)162
2020
JHEP09(2020)162
Published o SISSA by Sp inge
Recei ed:May 5, 2020
Re ised:July 30, 2020
Accep ed:Augus 20, 2020
Published:Sep embe 25, 2020
J/ψ p oduc ion as a unc ion o cha ged-pa icle
mul iplici y in p-Pb collisions a √sNN = 8.16 TeV
The ALICE collabo a ion
E-mail: [email p o ec ed]
Abs ac : Inclusi e J/ψ yields and a e age ans e se momen a in p-Pb collisions a a
cen e -o -mass ene gy pe nucleon pai √sNN = 8.16 TeV a e measu ed as a unc ion o he
cha ged-pa icle pseudo apidi y densi y wi h ALICE. The J/ψ mesons a e econs uc ed
a o wa d (2.03 < ycms <3.53) and backwa d (−4.46 < ycms <−2.96) cen e -o -mass
apidi y in hei dimuon decay channel while he cha ged-pa icle pseudo apidi y densi y
is measu ed a ound mid apidi y. The J/ψ yields a o wa d and backwa d apidi y no -
malized o hei espec i e a e age alues inc ease wi h he no malized cha ged-pa icle
pseudo apidi y densi y, he o me showing a weake inc ease han he la e . The no -
malized a e age ans e se momen a a o wa d and backwa d apidi y mani es a s eady
inc ease om low o high cha ged-pa icle pseudo apidi y densi y wi h a sa u a ion beyond
he a e age alue.
Keywo ds: Had on-Had on sca e ing (expe imen s), Pa icle co ela ions and luc ua-
ions
A Xi eP in : 2004.12673
Open Access, Copy igh CERN,
o he bene i o he ALICE Collabo a ion.
A icle unded by SCOAP3.
h ps://doi.o g/10.1007/JHEP09(2020)162
JHEP09(2020)162
Con en s
1 In oduc ion 1
2 Expe imen al se up and da a samples 2
3 Cha ged-pa icle mul iplici y measu emen 3
4 J/ψ measu emen 4
5 Sys ema ic unce ain ies 7
6 Resul s and discussion 9
7 Conclusions 14
The ALICE collabo a ion 22
1 In oduc ion
Qua konium s a es ha e long been conside ed as p obes o he Qua k-Gluon Plasma (QGP)
p oduced in ul a- ela i is ic hea y-ion collisions [1]. The la ge colo -cha ge densi y in
he plasma p e en s he o ma ion o bound s a es, in an analogous p ocess o he De-
bye sc eening o elec omagne ic p ocesses [2]. The supp ession o J/ψ p oduc ion in
nucleus-nucleus (AA) wi h espec o p o on-p o on (pp) collisions was obse ed by se e al
expe imen s [3–11]. To de e mine whe he he o igin o his supp ession is he in luence o
he QGP o o Cold Nuclea Ma e (CNM), da a on p o on(deu e on)-nucleus collisions
a e also sc u inized.
The measu emen s in p-Pb collisions a he LHC show a supp ession o J/ψ p oduc-
ion [12–14], wi h espec o pp collisions, a low ans e se momen um (pT) and o wa d
cen e -o -mass apidi y (p-going di ec ion, posi i e ycms), consis en wi h a ious combina-
ions o CNM e ec s: modi ica ion o he pa on dis ibu ion unc ions (PDFs) in nuclei,
i.e. shadowing [15,16], he Colo -Glass Condensa e (CGC) [17,18], o cohe en pa on
ene gy loss [19]. The measu emen o ψ(2S) p oduc ion in p-Pb collisions [20] exhibi s a
la ge supp ession, wi h espec o pp collisions, han he one measu ed o J/ψ, bo h a
o wa d and backwa d apidi y, which was no expec ed om CNM p edic ions. This e ec
is ep oduced by models which conside he b eak-up o he bound qua k-an i-qua k pai
ia in e ac ions wi h he inal-s a e como ing pa icles [21,22].
The p-Pb da a a he cen e -o -mass ene gy pe nucleon-nucleon collision o √sNN =
5.02 TeV [23,24] showed ha hese e ec s depend on he cen ali y o he collision, as
– 1 –
JHEP09(2020)162
es ima ed om he ene gy deposi ed in he Ze o Deg ee Calo ime e in he Pb-going di ec-
ion [25], and/o he p oduced cha ged-pa icle mul iplici y [26]. An inc ease o he no -
malized J/ψ and Υ [26–28] yields, o hei espec i e a e age alues, wi h he no malized
cha ged-pa icle mul iplici y is obse ed, simila ly o he esul s om pp collisions [27–29].
The inc ease o he J/ψ (p omp and non-p omp ) no malized yields was obse ed o be
simila o he inc ease o D mesons [30,31], sugges ing ha he o igin o he end is com-
mon o cha m and beau y p oduc ion, and ha had oniza ion does no play a dominan
in luence on his measu emen . The exci ed- o-g ound s a e a ios, Υ(nS)/Υ(1S), we e
ound o dec ease wi h inc easing cha ged-pa icle mul iplici y, which was no expec ed
om CNM p edic ions [27,28].
The measu emen s o wo-pa icle angula co ela ions in small sys ems ha e shown
in e es ing s uc u es in he angula co ela ion unc ion. A nea -side idge, loca ed a
(∆ϕ)≈0, is obse ed in high-mul iplici y pp [32] and p-Pb [33] collisions, accompanied by
an away-side s uc u e, loca ed a ∆ϕ≈πand exceeding he away-side je con ibu ion,
in p-Pb collisions [34,35]. These s uc u es a e eminiscen o hose in Pb-Pb da a [36],
in e p e ed as signa u es o he collec i e mo ion o he pa icles du ing he hyd ody-
namic e olu ion o he ho and dense medium. Co ela ions o J/ψ (a la ge apidi y) and
cha ged pa icles (a mid apidi y) in p-Pb collisions [37,38] e ealed pe sis ing long- ange
co ela ion s uc u es a high pT, simila o hose obse ed wi h cha ged had ons. The co -
esponding ellip ic low coe icien s a e ound o be posi i e and o compa able magni ude
o hose measu ed in Pb-Pb collisions [39–41], indica ing ha he mechanism a i s o igin
could be simila in bo h collision sys ems.
This le e epo s he measu emen o he mul iplici y-di e en ial inclusi e J/ψ yield
and a e age ans e se momen um in p-Pb collisions a √sNN = 8.16 TeV. The J/ψ mesons
a e econs uc ed a o wa d and backwa d cen e -o -mass apidi ies in hei dimuon decay
channel. The cha ged-pa icle pseudo apidi y densi y is measu ed a ound mid apidi y.
I complemen s and ex ends p e ious J/ψ measu emen s pe o med as a unc ion o he
collision cen ali y and he cha ged-pa icle mul iplici y a √sNN = 5.02 TeV [23,26]. The
classi ica ion o e en s as a unc ion o hei cha ged-pa icle pseudo apidi y densi y enables
he sc u iny o a e e en s, co esponding o he 0.01–0.04% highes mul iplici ies in he
collision. This allows p-Pb e en s o be s udied om low mul iplici ies, simila o hose
o pp collisions, up o e y la ge mul iplici ies co esponding o ∼100 p oduced cha ged
pa icles pe apidi y uni , simila o hose o pe iphe al Pb-Pb collisions, which exhibi
collec i e-like e ec s.
2 Expe imen al se up and da a samples
In his sec ion, he de ec o subsys ems ele an o his analysis a e p esen ed. A comple e
desc ip ion o he ALICE de ec o and i s pe o mance can be ound in [42,43].
The muon spec ome e [42,43] co e s he pseudo apidi y window o −4.0< η < −2.5
and consis s o : a 4 m long composi e on abso be , co esponding o abou 10 in e ac ion
leng hs (10 λin ), s a ing a 90 cm om he nominal in e ac ion poin , en laye s o muon
acking chambe s (MCH), coupled o a dipole magne wi h a 3 Tm ield in eg al, and
– 2 –
JHEP09(2020)162
ou laye s o muon igge chambe s (MTR). The MCH and MTR sys ems a e sepa a ed
by an addi ional i on wall o abou 7.2λin ha abso bs he emaining had onic and low-
momen um pa icle con amina ion. A ea abso be posi ioned downs eam o he MTR
il e s ou he backg ound om beam-gas in e ac ions. A conical abso be su ounds he
beam pipe and p o ec s he spec ome e agains seconda y pa icles p oduced mainly by
la ge-ηp ima y pa icles in e ac ing wi h he beam pipe.
The Silicon Pixel De ec o (SPD) [44] is he inne mos pa o he Inne T acking
Sys em (ITS). I consis s o wo cylind ical silicon pixel laye s a adial dis ances o
3.9 and 7.6 cm om he beam line. The espec i e pseudo apidi y co e age o he wo
laye s a e |η|<2 and |η|<1.4. The SPD is used o econs uc he p ima y e ex and o
measu e he cha ged-pa icle pseudo apidi y densi y a mid apidi y.
The V0 scin illa o a ays [45] a e loca ed a each side o he in e ac ion poin , co e ing
he pseudo apidi y anges o −3.7< η < −1.7 and 2.8< η < 5.1. In his analysis, he V0
p o ides an online igge and helps o ejec con amina ion om beam-gas e en s.
The neu on Ze o Deg ee Calo ime e (ZDC) [42] loca ed a abou 112.5 m on ei he
side om he in e ac ion poin a e used o ejec elec omagne ic in e ac ions and beam-
induced backg ound.
The esul s p esen ed in his le e a e ob ained wi h da a eco ded du ing he p-Pb un
a √sNN = 8.16 TeV in 2016. The J/ψ a e econs uc ed in he dimuon channel wi h da a
aken in wo di e en beam con igu a ions. Due o he asymme y o he beam ene gy pe
nucleon in p-Pb collisions a he LHC, he nucleon-nucleon cen e -o -mass apidi y ame is
shi ed by ∆y= 0.465 in he di ec ion o he p o on beam. As a consequence, he J/ψ a e
measu ed in he o wa d apidi y ange o 2.03 < ycms <3.53 (wi h p o ons going in he
di ec ion o he muon spec ome e , p-going di ec ion) and in he backwa d apidi y egion
−4.46 < ycms <−2.96 (Pb-going di ec ion). E en s used in his analysis we e collec ed
wi h a dedica ed dimuon igge which equi es he coincidence o signals in bo h V0 a ays
(minimum bias igge , MB) wi h a leas wo opposi e-sign muons egis e ed in he MTR.
The igge has an adjus able online h eshold, which o his da a sample was se o only
accep muons wi h ans e se momen a pT>0.5 GeV/c(pT o which an e iciency o 50%
is eached). The pTdi e en ial single-muon igge e iciency eaches a pla eau o ∼96% a
pT∼1.5 GeV/c. In his da a- aking pe iod, he maximum pile-up p obabili y was abou
4%. A dedica ed e en -selec ion s a egy — exploi ing he signals in he V0 and he ZDC,
he co ela ion o he numbe o clus e s and ack segmen s econs uc ed in he SPD, as
well as an algo i hm o ag e en s wi h mul iple e ices — allowed us o keep he pile-up
below 0.5% o he analysed e en s, e en a la ge mul iplici ies. The da a sample analyzed
co esponds o an in eg a ed luminosi y o Lin = 7.2±0.2 nb−1(10.6±0.3 nb−1) o he
p-going (Pb-going) con igu a ion [46].
3 Cha ged-pa icle mul iplici y measu emen
The cha ged-pa icle pseudo apidi y densi y (dNch/dη) is measu ed a mid apidi y exploi -
ing he in o ma ion p o ided by he SPD de ec o [47,48]. I is e alua ed by coun ing he
numbe o ackle s (N ackle ), i.e. ack segmen s joining pai s o hi s in he wo laye s
o he SPD poin ing o he p ima y e ex. The p ima y e ex is also compu ed wi h
– 3 –
JHEP09(2020)162
Sou ce |η|<1
Nco
ackle o dNch/dηco ela ion 0.1–6.9(5.8)%
z- e ex dependence 3%
Mon e Ca lo e en gene a o 2%
hdNch/dηi4%
Table 1. Sou ces o sys ema ic unce ain ies on he no malized cha ged-pa icle mul iplici y. Fo
he Nco
ackle o dNch/dηco ela ion an in e al is quo ed, a ying wi h mul iplici y, wi h a di e en
maximum unce ain y o he Pb(p)-going con igu a ion.
he SPD in o ma ion. To minimize non-uni o mi ies in he SPD accep ance, only e en s
wi h a z- e ex posi ion de e mined wi hin |z x|<10 cm a e conside ed, and ackle s a e
coun ed wi hin |η|<1.
The aw N ackle coun s a e co ec ed (Nco
ackle ) o he a ia ion o he de ec o condi-
ions wi h ime ( ac ion o ac i e SPD channels) and i s limi ed accep ance as a unc ion
o z x using a da a-d i en e en -by-e en co ec ion [29,30]. This co ec ion ensu es a
uni o m esponse as a unc ion o z x. In his analysis, he co ec ion is done by eno mal-
ising he N ackle (z x) dis ibu ions o he o e all maximum wi h a Poissonian smea ing
o accoun o he luc ua ions. The e en s a e sliced in Nco
ackle in e als. Mon e Ca lo
(MC) simula ions using he DPMJET [49] e en gene a o and he GEANT3 anspo
code [50] a e used o es ima e dNch/dη om Nco
ackle . A second o de polynomial co ela-
ion is assumed be ween hese wo quan i ies o he ull Nco
ackle in e al. Se e al sou ces
o sys ema ic unce ain y we e aken in o accoun . Possible de ia ions om he second
o de polynomial co ela ion we e es ima ed by using o he unc ions o quan i y he co -
ela ion o MC a e ages in each in e al, wi h alues anging om 0.1% a in e media e
mul iplici ies o 6.9% (5.8%) a he lowes (highes ) mul iplici y in e als. The sys em-
a ic unce ain y on he esidual z x dependence due o di e ences be ween da a and MC
amoun s o 3%. Finally, he e en gene a o in luence was conside ed and e alua ed by
compa ing he DPMJET simula ions wi h e en s gene a ed in EPOS [51], esul ing in a
2% unce ain y.
The a e age cha ged-pa icle pseudo apidi y densi y, hdNch/dηi, in non-single di ac-
i e (NSD) e en s was ob ained om an independen analysis and amoun s o hdNch/dηi=
20.33 ±0.83 (20.32 ±0.83) in p-Pb (Pb-p) collisions o |η|<1 [48], whe e he quo ed un-
ce ain y is sys ema ic.
Table 1summa izes he con ibu ions o he no malized cha ged-pa icle mul iplici y
unce ain y. The o al unce ain y is e alua ed assuming ha he di e en sou ces a e
unco ela ed.
4 J/ψ measu emen
The no malized J/ψ yield, i.e. he yield in each mul iplici y in e al ino malized o he
mul iplici y-in eg a ed alue, is e alua ed as
dNi/dy
hdN/dyi=Ni
J/ψ
NJ/ψ
Neq
MB
Ni,eq
MB
(Aε)J/ψ
(Aε)i
J/ψ
εi
MB
εMB
,(4.1)
– 4 –
JHEP09(2020)162
om he econs uc ed numbe o J/ψ,NJ/ψ, he numbe o minimum bias (MB) e en s
equi alen o he analysed dimuon sample, Neq
MB, he J/ψ accep ance and e iciency co ec-
ion, (Aε)J/ψ, and he NSD e en selec ion e iciency in he minimum bias sample, εMB.
The J/ψ a e econs uc ed o each mul iplici y in e al by combining opposi e-sign
muons and compu ing he in a ian mass o he pai s. The muon iden i ica ion is ensu ed
by equi ing ha he ack candida es econs uc ed in he MCH ha e a ma ching ack
segmen in he MTR. Fu he mo e, he indi idual acks mus ul ill he ollowing c i e ia
o make su e hey a e wi hin he accep ance o he spec ome e : hei adial dis ance om
he beam axis a he end o he on abso be is wi hin 17.6< Rabs <89.5 cm and hei
pseudo apidi y in he de ec o e e ence ame is wi hin −4< η < −2.5.
To ex ac he signal, he in a ian -mass dis ibu ions a e i s co ec ed o he J/ψ
accep ance imes e iciency (Aε), di e en ially in pTand y. The esul ing dis ibu ions
a e hen i ed wi h a supe posi ion o J/ψ and ψ(2S) signals and a backg ound lineshape.
Va ious combina ions o lineshapes a e used in o de o e alua e he signal coun s and
hei unce ain ies. The wo cha monium esonances a e pa ame ized by a sum o ei he
wo C ys al Ball o wo pseudo-Gaussian unc ions wi h powe -law ails [52]. The ail
pa ame iza ions a e ixed o he alues de e mined om ei he i s o he J/ψ signal om
MC simula ions o o alues aken om i s o he mul iplici y-in eg a ed dis ibu ion in
p-Pb da a a √sNN = 8.16 TeV [13] and in pp da a a √s= 13 TeV [53]. The
ails ob ained om i ing he mul iplici y-in eg a ed dis ibu ions using he C ys al Ball
unc ion a e also conside ed, and ixed in he binned i s. The J/ψ peak mean posi ion
and wid h a e le ee in he mul iplici y-in eg a ed i , whils he ψ(2S) ones a e bound
o hose o he J/ψ ollowing he same p ocedu e as in [54]. No e ha he ψ(2S) yields
ob ained a e no physical alues, as he in a ian -mass spec um is co ec ed by he Aε
co ec ion o he J/ψ. In he mul iplici y-di e en ial i s, he mass and wid h o he J/ψ
peak a e ixed o he in eg a ed alues o ensu e he con e gence o he i s in he ew cases
whe e s a is ical signi icance is low. The backg ound is pa ame e ized by ei he a sum o
wo exponen ials o he p oduc o an exponen ial and a ou h-o de polynomial. Two i
mass anges a e aken in o accoun when compu ing he a e age numbe o J/ψ and i s
unce ain y: 1.7< mµµ <4.8 GeV/c2and 2.0< mµµ <5.0 GeV/c2. Examples o i s a
low, in e media e, and high mul iplici y o da a in he apidi y ange 2.03 < ycms <3.53
a e shown in igu e 1. The signal lineshape is ound o be independen o mul iplici y,
while he backg ound does change wi h mul iplici y. The e o e, in o de o minimize he
unce ain y on he signal ex ac ion, he same signal lineshape is used in he i unc ion
o bo h he nume a o and denomina o in eq. 4.1.
The numbe o equi alen MB e en s Neq
MB is compu ed om he numbe o dimuon
igge ed e en s, Nµµ, and he no maliza ion ac o o dimuon igge ed o MB e en s
(calcula ed as explained in nex sec ion) as Neq
MB =Fno m ·Nµµ. The numbe needs o
be co ec ed o by he NSD e en selec ion e iciency, εMB = (97 ±1)% [48], o ake in o
accoun he ac ion o e en s wi hou a econs uc ed SPD e ex ha a e ejec ed. This
ac o εMB is ound o be independen o he cha ged-pa icle mul iplici y in all he in e als
s udied, wi h he excep ion o he lowes mul iplici y in e al, whe e i dec eases by 1%.
The J/ψ accep ance and e iciency co ec ion is ob ained om MC simula ions as a
unc ion o pTand ycms. The J/ψ a e gene a ed using pTand ycms dis ibu ions uned
– 5 –
JHEP09(2020)162
2 2.5 3 3.5 4 4.5
)
2
c (GeV/
µµ
m
2000
4000
6000
8000
10000
2
ccoun s pe 50 MeV/
= 8.16 TeV
NN
sPb, −ALICE, p
< 3.53
cms
y2.03 <
< 10
ackle s
co
N ≤1
423± = 18328
ψJ/
N
2
c 2 MeV/± = 3095
ψJ/
µ
2
c 2 MeV/± = 75
ψJ/
σ
2 2.5 3 3.5 4 4.5
)
2
c (GeV/
µµ
m
2000
4000
6000
8000
10000
2
ccoun s pe 50 MeV/
= 8.16 TeV
NN
sPb, −ALICE, p
< 3.53
cms
y2.03 <
< 52
ackle s
co
N ≤49
762± = 27843
ψJ/
N
2
c 2 MeV/± = 3096
ψJ/
µ
2
c 2 MeV/± = 76
ψJ/
σ
2 2.5 3 3.5 4 4.5
)
2
c (GeV/
µµ
m
2000
4000
6000
8000
10000
2
ccoun s pe 50 MeV/
= 8.16 TeV
NN
sPb, −ALICE, p
< 3.53
cms
y2.03 <
< 155
ackle s
co
N ≤111
520± = 14032
ψJ/
N
2
c 3 MeV/± = 3096
ψJ/
µ
2
c 3 MeV/± = 72
ψJ/
σ
Figu e 1. Opposi e-sign muon pai in a ian mass dis ibu ions o selec ed mul iplici y in e als,
co ec ed o he J/ψ accep ance and e iciency, a o wa d apidi y. The dis ibu ions a e shown
oge he wi h a ypical i unc ion (solid line, see ex o de ails). The J/ψ signal con ibu ion is
also depic ed by a do -dashed ed line, and he backg ound by a do ed line.
o da a [13]. They a e simula ed o decay in o a muon pai using E Gen [55]. The inal
s a e adia ion is desc ibed wi h PHOTOS [56]. The accep ance and e iciency co ec ion
is independen o mul iplici y in he measu emen in e als. The e o e, when es ima ing
he unce ain y on he MC inpu , only he possible a ia ion o he inpu pTand ycms
dis ibu ions is aken in o accoun by using as inpu a subsample o he lowe /highe
mul iplici y e en s.
To ex ac he J/ψ mean ans e se momen um hpJ/ψ
Ti, he Aε-co ec ed ans e se
momen um o he dimuon pai is i ed wi h he ollowing unc ion [26]:
hpµµ
Ti(mµµ) = αJ/ψ(mµµ)hpJ/ψ
Ti
+αψ0(mµµ)hpψ0
Ti
+1−αJ/ψ(mµµ)−αψ0(mµµ)hpbkgd
Ti(mµµ),
(4.2)
whe e he a ios o signal o e he sum o signal and backg ound o he wo cha monium
– 6 –
JHEP09(2020)162
2 2.5 3 3.5 4 4.5 5
)
2
c (GeV/
µµ
m
1.5
2
2.5
3
3.5
4
)c (GeV/〉
µµ
T
p〈
= 8.16 TeV
NN
sPb, −ALICE, p
< 3.53
cms
y2.03 <
c 0.03 GeV/± = 2.45 〉
ψJ/
T
p〈
< 10
ackle s
co
N ≤1
2 2.5 3 3.5 4 4.5 5
)
2
c (GeV/
µµ
m
1.5
2
2.5
3
3.5
4
)c (GeV/〉
µµ
T
p〈
= 8.16 TeV
NN
sPb, −ALICE, p
< 3.53
cms
y2.03 <
c 0.05 GeV/± = 2.79 〉
ψJ/
T
p〈
< 155
ackle s
co
N ≤111
Figu e 2. A e age ans e se momen um o opposi e-sign muon pai s o selec ed mul iplici y
in e als, co ec ed o he J/ψ accep ance and e iciency. The dis ibu ions a e shown oge he
wi h a ypical i unc ion (solid line, see ex o de ails).
s a es αJ/ψ =SJ/ψ/(SJ/ψ +Sψ0+B) and αψ0=Sψ0/(SJ/ψ +Sψ0+B) a e ixed o he
alue ex ac ed om i ing he in a ian -mass spec um co ec ed by he J/ψ Aε. The
backg ound is desc ibed by a unc ion hpbkgd
Ti(mµµ). Two unc ional o ms a e used: ei he
a sum o wo exponen ials o he p oduc o an exponen ial and a ou h-o de polyno-
mial. No e ha he hpψ0
Tidoes no ep esen a physical mean ans e se momen um o he
ψ(2S) as he spec a a e co ec ed by he Aε o J/ψ. Figu e 2illus a es ypical hpµµ
Ti
dis ibu ions o selec ed mul iplici y in e als.
5 Sys ema ic unce ain ies
The ollowing sou ces o sys ema ic unce ain y on he J/ψ yields in mul iplici y classes
a e conside ed:
(i) he signal ex ac ion,
(ii) he no malisa ion,
(iii) he e ec o esolu ion and pile-up,
(i ) he e en -by-e en N ackle o Nco
ackle co ec ion, and
( ) he e en selec ion e iciency o he NSD e en class.
Fo he measu emen o he yields in each mul iplici y in e al no malized o he e en a e -
age, he sys ema ic unce ain ies a e es ima ed di ec ly o his a io. De ails on he signal
ex ac ion unce ain y we e add essed in he p e ious sec ion. The alues a e es ima ed
by a ying he signal and backg ound shapes o he i unc ion, as well as by a ying he
in a ian -mass ange o he i . The sys ema ic unce ain y is compu ed as he oo -mean-
squa e o he unce ain ies on he a io o each o hese i s, anging be ween 0.8–2.3%
(0.5–1.9%) a o wa d (backwa d) apidi y, being la ge a la ge mul iplici ies whe e he
– 7 –
JHEP09(2020)162
0 2 4 6
|<1
η
|
NSD
〉
η
/ d
ch
Nd〈
η
/ d
ch
Nd
0.7
0.8
0.9
1
1.1
1.2
NSD
〉
in
T
p 〈 / 〉
T
p 〈
Pb−ALICE, p
< 3.53 (p-going)
cms
y2.03 <
-
µ
+
µ → ψJ/
= 8.16 TeV
NN
s
= 5.02 TeV
NN
s
0 2 4 6
|<1
η
|
NSD
〉
η
/ d
ch
Nd〈
η
/ d
ch
Nd
0.7
0.8
0.9
1
1.1
1.2
NSD
〉
in
T
p 〈 / 〉
T
p 〈
Pb−ALICE, p
2.96 (Pb-going)− <
cms
y4.46 < −
-
µ
+
µ → ψJ/
= 8.16 TeV
NN
s
= 5.02 TeV
NN
s
Figu e 7. No malized a e age ans e se momen um o inclusi e J/ψ as a unc ion o he no -
malized cha ged-pa icle pseudo apidi y densi y, measu ed a mid apidi y, in p-Pb collisions a
√sNN = 8.16 TeV and √sNN = 5.02 TeV [26]. Top (bo om) panel p esen s he measu emen
a o wa d (backwa d) apidi y. The e ical ba s ep esen he s a is ical unce ain ies, he boxes
he sys ema ic ones.
in e p e he simila i ies o pp, p-Pb, and Pb-Pb no malized J/ψ yields a la ge apidi y
as a unc ion o he no malized cha ged-pa icle pseudo apidi y densi y a mid apidi y.
7 Conclusions
The p oduc ion o inclusi e J/ψ a la ge apidi ies in p-Pb collisions a √sNN = 8.16 TeV is
epo ed as a unc ion o he cha ged-pa icle pseudo apidi y densi y a mid apidi y. The
no malized J/ψ yield shows an inc ease wi h inc easing no malised cha ged-pa icle pseu-
do apidi y densi y. The yield a backwa d apidi y g ows as e han he o wa d apidi y
one, eaching alues abo e hose o he linea (wi h slope uni y) inc ease es ima e a la ge
– 14 –
JHEP09(2020)162
0 2 4 6
|<1
η
|
〉
η
/ d
ch
Nd〈
η
/ d
ch
Nd
0
2
4
6
8
〉y / dNd〈
y / dNd
ALICE
-
µ
+
µ → ψJ/
= 8.16 TeV
NN
s
Pb, −p
< 3.53 (p-going)
cms
y2.03 <
2.96 (Pb-going)− <
cms
y4.46 < −
< 4.0
cms
y2.5 <
= 7 TeVs
pp,
= 5.02 TeV
NN
sPb, −Pb
1.5% co . unc. no shown a 7 TeV± 1% co . unc. no shown a 8.16 TeV±
0 2 4 6
|<1
η
|
〉
η
/ d
ch
Nd〈
η
/ d
ch
Nd
0
0.5
1
1.5
2
〉
η
/ d
ch
Nd〈
η
/ d
ch
Nd
/
〉y / dNd〈
y / dNd
ALICE
-
µ
+
µ → ψJ/
= 8.16 TeV
NN
s
Pb, −p
< 3.53 (p-going)
cms
y2.03 <
2.96 (Pb-going)− <
cms
y4.46 < −
< 4.0
cms
y2.5 <
= 7 TeVs
pp,
= 5.02 TeV
NN
sPb, −Pb 1.5% co . unc. no shown a 7 TeV± 1% co . unc. no shown a 8.16 TeV±
Figu e 8. Top: no malized yield o inclusi e J/ψ as a unc ion o he no malized cha ged-pa icle
pseudo apidi y densi y, measu ed a mid apidi y, in a ious collision sys ems. Bo om: a io o he
no malized yields o he co esponding no malized cha ged-pa icle pseudo apidi y densi y. The pp
esul s a e no malized o INEL collisions [29], whe eas p-Pb ones e e o he NSD e en class; all
o pT>0. The Pb-Pb da a poin s include J/ψ wi h 0.3< pT<12 GeV/c o educe he low-pT
con ibu ion om pho op oduc ion, which is signi ican only in mo e pe iphe al collisions [62,64,
65]. The e ical ba s ep esen he s a is ical unce ain ies, he boxes he sys ema ic ones. The
dashed line indica es he one- o-one co ela ion, o guide he eye.
no malised mul iplici y, whe eas he alues a o wa d apidi y show a slowe - han-linea
inc ease. The ends o he no malised yield a e ep oduced by he EPOS 3 [60,61] e en
gene a o . The hpTiis smalle a backwa d han a o wa d apidi y, consis en wi h he
expec ed so ening o he spec a wi h inc easing |ycms|. The hpTiinc eases s eadily o
mul iplici ies below he a e age, and sa u a es abo e he a e age mul iplici y. The simul a-
neous inc ease o he yield oge he wi h he sa u a ion o hpTimay poin o J/ψ p oduc ion
om an incohe en supe posi ion o pa on-pa on collisions. These measu emen s show
– 15 –
JHEP09(2020)162
ends compa ible wi h hose obse ed a √sNN = 5.02 TeV [26] in p-Pb collisions, bu
in his wo k an imp o ed p ecision and ex ended mul iplici y co e age we e eached. The
simila i ies sugges a common o igin, wi h a mechanism whose e ec a ies wi h apidi y,
bu wi h only a small dependence (i any) on he collision ene gy.
Acknowledgmen s
The ALICE Collabo a ion would like o hank all i s enginee s and echnicians o hei
in aluable con ibu ions o he cons uc ion o he expe imen and he CERN accele a o
eams o he ou s anding pe o mance o he LHC complex. The ALICE Collabo a ion
g a e ully acknowledges he esou ces and suppo p o ided by all G id cen es and he
Wo ldwide LHC Compu ing G id (WLCG) collabo a ion. The ALICE Collabo a ion ac-
knowledges he ollowing unding agencies o hei suppo in building and unning he
ALICE de ec o : A. I. Alikhanyan Na ional Science Labo a o y (Ye e an Physics Ins i-
u e) Founda ion (ANSL), S a e Commi ee o Science and Wo ld Fede a ion o Scien is s
(WFS), A menia; Aus ian Academy o Sciences, Aus ian Science Fund (FWF): [M 2467-
N36] and Na ionals i ung ¨u Fo schung, Technologie und En wicklung, Aus ia; Minis y
o Communica ions and High Technologies, Na ional Nuclea Resea ch Cen e , Aze baijan;
Conselho Nacional de Desen ol imen o Cien ´ı ico e Tecnol´ogico (CNPq), Financiado a de
Es udos e P oje os (Finep), Funda¸c˜ao de Ampa o `a Pesquisa do Es ado de S˜ao Paulo
(FAPESP) and Uni e sidade Fede al do Rio G ande do Sul (UFRGS), B azil; Minis y o
Educa ion o China (MOEC) , Minis y o Science & Technology o China (MSTC) and
Na ional Na u al Science Founda ion o China (NSFC), China; Minis y o Science and
Educa ion and C oa ian Science Founda ion, C oa ia; Cen o de Aplicaciones Tecnol´ogicas
y Desa ollo Nuclea (CEADEN), Cubaene g´ıa, Cuba; Minis y o Educa ion, You h and
Spo s o he Czech Republic, Czech Republic; The Danish Council o Independen Re-
sea ch — Na u al Sciences, he VILLUM FONDEN and Danish Na ional Resea ch Foun-
da ion (DNRF), Denma k; Helsinki Ins i u e o Physics (HIP), Finland; Commissa ia `a
l’Ene gie A omique (CEA) and Ins i u Na ional de Physique Nucl´eai e e de Physique
des Pa icules (IN2P3) and Cen e Na ional de la Reche che Scien i ique (CNRS), F ance;
Bundesminis e ium ¨u Bildung und Fo schung (BMBF) and GSI Helmhol zzen um ¨u
Schwe ionen o schung GmbH, Ge many; Gene al Sec e a ia o Resea ch and Technol-
ogy, Minis y o Educa ion, Resea ch and Religions, G eece; Na ional Resea ch, De elop-
men and Inno a ion O ice, Hunga y; Depa men o A omic Ene gy Go e nmen o India
(DAE), Depa men o Science and Technology, Go e nmen o India (DST), Uni e si y
G an s Commission, Go e nmen o India (UGC) and Council o Scien i ic and Indus ial
Resea ch (CSIR), India; Indonesian Ins i u e o Science, Indonesia; Cen o Fe mi - Museo
S o ico della Fisica e Cen o S udi e Rice che En ico Fe mi and Is i u o Nazionale di Fisica
Nuclea e (INFN), I aly; Ins i u e o Inno a i e Science and Technology , Nagasaki Ins i-
u e o Applied Science (IIST), Japanese Minis y o Educa ion, Cul u e, Spo s, Science
and Technology (MEXT) and Japan Socie y o he P omo ion o Science (JSPS) KAK-
ENHI, Japan; Consejo Nacional de Ciencia (CONACYT) y Tecnolog´ıa, h ough Fondo
de Coope aci´on In e nacional en Ciencia y Tecnolog´ıa (FONCICYT) and Di ecci´on Gen-
– 16 –
JHEP09(2020)162
e al de Asun os del Pe sonal Academico (DGAPA), Mexico; Nede landse O ganisa ie oo
We enschappelijk Onde zoek (NWO), Ne he lands; The Resea ch Council o No way, No -
way; Commission on Science and Technology o Sus ainable De elopmen in he Sou h
(COMSATS), Pakis an; Pon i icia Uni e sidad Ca ´olica del Pe ´u, Pe u; Minis y o Sci-
ence and Highe Educa ion, Na ional Science Cen e and WUT ID-UB, Poland; Ko ea
Ins i u e o Science and Technology In o ma ion and Na ional Resea ch Founda ion o Ko-
ea (NRF), Republic o Ko ea; Minis y o Educa ion and Scien i ic Resea ch, Ins i u e o
A omic Physics and Minis y o Resea ch and Inno a ion and Ins i u e o A omic Physics,
Romania; Join Ins i u e o Nuclea Resea ch (JINR), Minis y o Educa ion and Science
o he Russian Fede a ion, Na ional Resea ch Cen e Ku cha o Ins i u e, Russian Science
Founda ion and Russian Founda ion o Basic Resea ch, Russia; Minis y o Educa ion,
Science, Resea ch and Spo o he Slo ak Republic, Slo akia; Na ional Resea ch Foun-
da ion o Sou h A ica, Sou h A ica; Swedish Resea ch Council (VR) and Knu & Alice
Wallenbe g Founda ion (KAW), Sweden; Eu opean O ganiza ion o Nuclea Resea ch,
Swi ze land; Su ana ee Uni e si y o Technology (SUT), Na ional Science and Technol-
ogy De elopmen Agency (NSDTA) and O ice o he Highe Educa ion Commission unde
NRU p ojec o Thailand, Thailand; Tu kish A omic Ene gy Agency (TAEK), Tu key; Na-
ional Academy o Sciences o Uk aine, Uk aine; Science and Technology Facili ies Council
(STFC), Uni ed Kingdom; Na ional Science Founda ion o he Uni ed S a es o Ame ica
(NSF) and Uni ed S a es Depa men o Ene gy, O ice o Nuclea Physics (DOE NP),
Uni ed S a es o Ame ica.
Open Access. This a icle is dis ibu ed unde he e ms o he C ea i e Commons
A ibu ion License (CC-BY 4.0), which pe mi s any use, dis ibu ion and ep oduc ion in
any medium, p o ided he o iginal au ho (s) and sou ce a e c edi ed.
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JHEP09(2020)162
The ALICE collabo a ion
S. Acha ya141, D. Adamo ´a95, A. Adle 74, J. Adol sson81, M.M. Agga wal100, G. Aglie i Rinella34,
M. Agnello30, N. Ag awal10,54, Z. Ahammed141, S. Ahmad16, S.U. Ahn76, Z. Akba 51,
A. Akindino 92, M. Al-Tu any107, S.N. Alam141, D.S.D. Albuque que122, D. Aleksand o 88,
B. Alessand o59, H.M. Al anda6, R. Al a o Molina71, B. Ali16, Y. Ali14, A. Alici10,26,54,
A. Alkin2,34, J. Alme21, T. Al 68, L. Al enkampe 21, I. Al sybee 113, M.N. Anaam6, C. And ei48,
D. And eou34, H.A. And ews111, A. And onic144, M. Angele i34, V. Anguelo 104, C. Anson15,
T. An iˇci´c108, F. An ino i57, P. An onioli54, N. Apadula80, L. Aphece che115, H. Appelsh¨ause 68,
S. A celli26, R. A naldi59, M. A a ia80, I.C. A sene20, M. A slandok104, A. Augus inus34,
R. A e beck107, S. Aziz78, M.D. Azmi16, A. Badal`a56, Y.W. Baek41, S. Bagnasco59, X. Bai107,
R. Bailhache68, R. Bala101, A. Balbino30, A. Baldisse i137, M. Ball43, S. Balouza105, D. Bane jee3,
R. Ba be a27, L. Ba ioglio25, G.G. Ba na ¨oldi145, L.S. Ba nby94, V. Ba e 134, P. Ba alini6,
K. Ba h34, E. Ba sch68, F. Ba u aldi28, N. Bas id134, S. Basu143, G. Ba igne115, B. Ba yunya75,
D. Bau i49, J.L. Bazo Alba112, I.G. Bea den89, C. Bea ie146, C. Bedda63, N.K. Behe a61,
I. Beliko 136, A.D.C. Bell Hecha a ia144, F. Bellini34, R. Bellwied125, V. Belyae 93,
G. Bencedi145, S. Beole25, A. Be cuci48, Y. Be dniko 98, A. Be dniko a104, D. Be enyi145,
R.A. Be ens130, D. Be zano59, M.G. Besoiu67, L. Be e 34, A. Bhasin101, I.R. Bha 101,
M.A. Bha 3, H. Bha 49, B. Bha acha jee42, A. Bianchi25, L. Bianchi25, N. Bianchi52,
J. Bielˇc´ık37, J. Bielˇc´ıko ´a95, A. Bilandzic105, G. Bi o145, R. Biswas3, S. Biswas3, J.T. Blai 119,
D. Blau88, C. Blume68, G. Boca139, F. Bock96, A. Bogdano 93, S. Boi23, J. Bok61, L. Boldizs´a 145,
A. Bolozdynya93, M. Bomba a38, G. Bonomi140, H. Bo el137, A. Bo isso 93, H. Bossi146,
E. Bo a25, L. B a ud68, P. B aun-Munzinge 107, M. B egan 121, M. B oz37, E. B una59,
G.E. B uno106, M.D. Buckland127, D. Budniko 109, H. Buesching68, S. Bu alino30, O. Bugnon115,
P. Buhle 114, P. Buncic34, Z. Bu helezi72,131, J.B. Bu 14, S.A. Bysiak118, D. Ca a i90,
A. Cali a107, E. Cal o Villa 112, R.S. Camacho45, P. Came ini24, A.A. Capon114, F. Ca nesecchi26,
R. Ca on137, J. Cas illo Cas ellanos137, A.J. Cas o130, E.A.R. Casula55, F. Ca alano30,
C. Ceballos Sanchez53, P. Chak abo y49, S. Chand a141, W. Chang6, S. Chapeland34,
M. Cha ie 127, S. Cha opadhyay141, S. Cha opadhyay110, A. Chau in23, C. Cheshko 135,
B. Cheynis135, V. Chiban e Ba oso34, D.D. Chinella o122, S. Cho61, P. Chochula34,
T. Chowdhu y134, P. Ch is akoglou90, C.H. Ch is ensen89, P. Ch is iansen81, T. Chujo133,
C. Cicalo55, L. Ci a elli10,26, F. Cindolo54, G. Clai54,ii, J. Cleymans124, F. Colama ia53,
D. Colella53, A. Collu80, M. Colocci26, M. Concas59,iii, G. Conesa Balbas e79, Z. Conesa del
Valle78, G. Con in24,60, J.G. Con e as37, T.M. Co mie 96, Y. Co ales Mo ales25, P. Co ese31,
M.R. Cosen ino123, F. Cos a34, S. Cos anza139, J. C ko ska78, P. C oche 134, E. Cuau le69,
P. Cui6, L. Cunquei o96, D. Dab owski142, T. Dahms105, A. Dainese57, F.P.A. Damas115,137,
M.C. Danisch104, A. Danu67, D. Das110, I. Das110, P. Das86, P. Das3, S. Das3, A. Dash86,
S. Dash49, S. De86, A. De Ca o29, G. de Ca aldo53, J. de Cu eland39, A. De Falco23, D. De
G u ola10, N. De Ma co59, S. De Pasquale29, S. Deb50, H.F. Degenha d 121, K.R. Deja142,
A. Delo 85, S. Delsan o25,131, W. Deng6, D. De e ak107, P. Dhankhe 49, D. Di Ba i33, A. Di
Mau o34, R.A. Diaz8, T. Die el124, P. Dillensege 68, Y. Ding6, R. Di i`a34, D.U. Dixi 19,
Ø. Dju sland21, U. Dmi ie a62, A. Dob in67, B. D¨onigus68, O. Do dic20, A.K. Dubey141,
A. Dubla90,107, S. Dudi100, M. Dukhishyam86, P. Dupieux134, R.J. Ehle s96,146, V.N. Eikeland21,
D. Elia53, E. Epple146, B. E azmus115, F. E ha d 99, A. E okhin113, M.R. E sdal21,
B. Espagnon78, G. Eulisse34, D. E ans111, S. E dokimo 91, L. Fabbie i105, M. Faggin28,
J. Fai e79, F. Fan6, A. Fan oni52, M. Fasel96, P. Fecchio30, A. Feliciello59, G. Feo ilo 113,
A. Fe n´andez T´ellez45, A. Fe e o137, A. Fe e i25, A. Fes an i34, V.J.G. Feuilla d104, J. Figiel118,
S. Filchagin109, D. Finogee 62, F.M. Fionda21, G. Fio enza53, F. Flo 125, A.N. Flo es119,
– 22 –
JHEP09(2020)162
S. Foe sch72, P. Foka107, S. Fokin88, E. F agiacomo60, U. F anken eld107, U. Fuchs34, C. Fu ge 79,
A. Fu s62, M. Fusco Gi a d29, J.J. Gaa dhøje89, M. Gaglia di25, A.M. Gago112, A. Gal136,
C.D. Gal an120, P. Gano i84, C. Ga aba os107, E. Ga cia-Solis11, K. Ga g115, C. Ga giulo34,
A. Ga ibli87, K. Ga ne 144, P. Gasik105,107, E.F. Gauge 119, M.B. Gay Duca i70, M. Ge main115,
J. Ghosh110, P. Ghosh141, S.K. Ghosh3, M. Giacalone26, P. Giano i52, P. Giubellino59,107,
P. Giubila o28, P. Gl¨assel104, A. Gomez Rami ez74, V. Gonzalez107,143, L.H. Gonz´alez-T ueba71,
S. Go buno 39, L. G¨o lich118, A. Goswami49, S. Go o ac35, V. G abski71, L.K. G aczykowski142,
K.L. G aham111, L. G eine 80, A. G elli63, C. G igo as34, V. G igo ie 93, A. G igo yan1,
S. G igo yan75, O.S. G oe ik21, F. G osa30, J.F. G osse-Oe inghaus34, R. G osso107,
R. Gue nane79, M. Gui ie e115, K. Gulb andsen89, T. Gunji132, A. Gup a101, R. Gup a101,
I.B. Guzman45, R. Haake146, M.K. Habib107, C. Hadjidakis78, H. Hamagaki82, G. Hama 145,
M. Hamid6, R. Hannigan119, M.R. Haque63,86, A. Ha lende o a107, J.W. Ha is146, A. Ha on11,
J.A. Hasenbichle 34, H. Hassan96, D. Ha zi o iadou10,54, P. Haue 43, L.B. Ha ene 146,
S. Hayashi132, S.T. Heckel105, E. Hellb¨a 68, H. Hels up36, A. He ghelegiu48, T. He man37,
E.G. He nandez45, G. He e a Co al9, F. He mann144, K.F. He land36, H. Hillemanns34,
C. Hills127, B. Hippoly e136, B. Hohlwege 105, J. Hone mann144, D. Ho ak37, A. Ho nung68,
S. Ho nung107, R. Hosokawa15, P. H is o 34, C. Huang78, C. Hughes130, P. Huhn68,
T.J. Humanic97, H. Hushnud110, L.A. Huso a144, N. Hussain42, S.A. Hussain14, D. Hu e 39,
J.P. Iddon34,127, R. Ilkae 109, H. Ilyas14, M. Inaba133, G.M. Innocen i34, M. Ippoli o 88,
A. Isako 95, M.S. Islam110, M. I ano 107, V. I ano 98, V. Izuchee 91, B. Jacak80, N. Jacazio34,
P.M. Jacobs80, S. Jadlo ska117, J. Jadlo sky117, S. Jaelani63, C. Jahnke121, M.J. Jakubowska142,
M.A. Janik142, T. Janson74, M. Je cic99, O. Je ons111, M. Jin125, F. Jonas96,144, P.G. Jones111,
J. Jung68, M. Jung68, A. Jusko111, P. Kalinak64, A. Kalwei 34, V. Kaplin93, S. Ka 6, A. Ka asu
Uysal77, O. Ka a iche 62, T. Ka a iche a62, P. Ka czma czyk34, E. Ka peche 62, U. Kebschull74,
R. Keidel47, M. Keil34, B. Ke ze 43, Z. Khabano a90, A.M. Khan6, S. Khan16, S.A. Khan141,
A. Khanzadee 98, Y. Kha lo 91, A. Kha un16, A. Khun ia118, B. Kileng36, B. Kim61, B. Kim133,
D. Kim147, D.J. Kim126, E.J. Kim73, H. Kim17, J. Kim147, J.S. Kim41, J. Kim104, J. Kim147,
J. Kim73, M. Kim104, S. Kim18, T. Kim147, T. Kim147, S. Ki sch68, I. Kisel39, S. Kisele 92,
A. Kisiel142, J.L. Klay5, C. Klein68, J. Klein34,59, S. Klein80, C. Klein-B¨osing144, M. Kleine 68,
A. Kluge34, M.L. Knichel34, A.G. Knospe125, C. Kobdaj116, M.K. K¨ohle 104, T. Kollegge 107,
A. Kond a ye 75, N. Kond a ye a93, E. Kond a yuk91, J. Konig68, S.A. Konigs o e 105,
P.J. Konopka34, G. Ko nako 142, L. Koska117, O. Ko alenko85, V. Ko alenko113, M. Kowalski118,
I. K ´alik64, A. K a ˇc´ako ´a38, L. K eis107, M. K i da64,111, F. K izek95, K. K izko a Gajdoso a37,
M. K ¨uge 68, E. K yshen98, M. K zewicki39, A.M. Kube a97, V. Kuˇce a34,61, C. Kuhn136,
P.G. Kuije 90, L. Kuma 100, S. Kundu86, P. Ku ash ili85, A. Ku epin62, A.B. Ku epin62,
A. Ku yakin109, S. Kushpil95, J. K apil111, M.J. Kweon61, J.Y. Kwon61, Y. Kwon147, S.L. La
Poin e39, P. La Rocca27, Y.S. Lai80, R. Langoy129, K. Lapidus34, A. La deux20, P. La iono 52,
E. Laudi34, R. La icka37, T. Laza e a113, R. Lea24, L. Lea dini104, J. Lee133, S. Lee147,
F. Lehas90, S. Lehne 114, J. Leh bach39, R.C. Lemmon94, I. Le´on Monz´on120, E.D. Lesse 19,
M. Le ich34, P. L´e ai145, X. Li12, X.L. Li6, J. Lien129, R. Lie a a111, B. Lim17,
V. Lindens u h39, A. Lindne 48, S.W. Lindsay127, C. Lippmann107, M.A. Lisa97, A. Liu19,
J. Liu127, S. Liu97, W.J. Llope143, I.M. Lo nes21, V. Logino 93, C. Loizides96, P. Lonca 35,
J.A. Lopez104, X. Lopez134, E. L´opez To es8, J.R. Luhde 144, M. Luna don28, G. Lupa ello60,
Y.G. Ma40, A. Mae skaya62, M. Mage 34, S.M. Mahmood20, T. Mahmoud43, A. Mai e136,
R.D. Majka146,i, M. Malae 98, Q.W. Malik20, L. Malinina75,i , D. Mal’Ke ich92,
P. Malzache 107, G. Mandaglio32,56, V. Manko88, F. Manso134, V. Manza i53, Y. Mao6,
M. Ma chisone135, J. Ma eˇs66, G.V. Ma gaglio i24, A. Ma go i54, J. Ma gu i63, A. Ma ´ın107,
C. Ma ke 119, M. Ma qua d68, C.D. Ma in24, N.A. Ma in104, P. Ma inengo34,
– 23 –