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P oduc ion o pions, kaons, (an i-)p o ons and ϕ mesons in Xe–Xe collisions a
√sNN = 5.44 TeV
© CERN o he bene i o he ALICE collabo a ion 2021
Published e sion
ALICE Collabo a ion
ALICE Collabo a ion. (2021). P oduc ion o pions, kaons, (an i-)p o ons and ϕ mesons in Xe–Xe
collisions a √sNN = 5.44 TeV. Eu opean Physical Jou nal C, 81(7), A icle 584.
h ps://doi.o g/10.1140/epjc/s10052-021-09304-4
2021
Eu . Phys. J. C (2021) 81:584
h ps://doi.o g/10.1140/epjc/s10052-021-09304-4
Regula A icle - Expe imen al Physics
P oduc ion o pions, kaons, (an i-)p o ons and φmesons in Xe–Xe
collisions a √sNN =5.44TeV
ALICE Collabo a ion
CERN, 1211 Gene a 23, Swi ze land
Recei ed: 27 Janua y 2021 / Accep ed: 31 May 2021
© CERN o he bene i o he ALICE collabo a ion 2021
Abs ac The i s measu emen o he p oduc ion o
pions, kaons, (an i-)p o ons and φmesons a mid apidi y in
Xe–Xe collisions a √sNN =5.44 TeV is p esen ed. T ans-
e se momen um (pT) spec a and pT-in eg a ed yields a e
ex ac ed in se e al cen ali y in e als b idging om p–Pb
o mid-cen al Pb–Pb collisions in e ms o inal-s a e mul-
iplici y. The s udy o Xe–Xe and Pb–Pb collisions allows
sys ems a simila cha ged-pa icle mul iplici ies bu wi h
di e en ini ial geome ical eccen ici ies o be in es iga ed.
A de ailed compa ison o he spec al shapes in he wo sys-
ems e ealsanopposi ebeha iou o adialandellip ic low.
In pa icula , his s udy shows ha he adial low does no
depend on he colliding sys em when compa ed a simila
cha ged-pa icle mul iplici y. In e ms o had on chemis y,
he p e iously obse ed smoo h e olu ion o pa icle a ios
wi h mul iplici y om small o la ge collision sys ems is also
ound o hold in Xe–Xe. In addi ion, ou esul s con i m ha
wo ema kable ea u es o pa icle p oduc ion a LHC ene -
gies a e also alid in he collision o medium-sized nuclei:
he lowe p o on- o-pion a io wi h espec o he he mal
model expec a ions and he inc ease o he φ- o-pion a io
wi h inc easing inal-s a e mul iplici y.
1 In oduc ion
In ecen yea s, he p oduc ion o had ons consis ing o ligh
la ou qua ks(u,d,ands)hasbeenex ensi elys udiedinpp,
p–Pb and Pb–Pb collisions a LHC ene gies [1–11] wi h he
aim o explo e he s ongly in e ac ing Qua k-Gluon Plasma
(QGP)p oducedinhea y-ion collisions. A e he o ma ion,
he QGP expands hyd odynamically eaching i s a chemi-
cal eeze-ou , whe e had on abundances a e ixed [12,13],
and hen a kine ic eeze-ou , whe e he had on momen a a e
ixed.
Rema kably, a smoo h e olu ion o he had on chemis y,
i.e. o he ela i e abundance o had on species, was obse ed
ac oss di e en collision sys ems as a unc ion o he inal-
e-mail: [email p o ec ed]
s a e mul iplici y [9]. This beha iou was also ound o be
independen o collision ene gy [10]. In pa icula , he ela-
i e abundance o s ange pa icles wi h espec o he non-
s ange ones inc eases con inuously om small o la ge mul-
iplici ies un il a sa u a ion is obse ed o sys ems in which
abou 100 cha ged pa icles a e p oduced pe uni o pseu-
do apidi y [8]. This obse a ion sugges s a g adual app oach
o a chemical equilib ium ha is assumed o o igina e om
he same unde lying physical mechanisms ac oss di e en
collision sys ems [14–16]. The s udy o he pion, kaon, (an i-
)p o on, and φp oduc ion in he collisions o medium-sized
nuclei such as Xe p o ides he ul ima e es o alida ing
his pic u e by b idging he gap be ween p–Pb and Pb–Pb
mul iplici ies.
In his con ex , wo ema kable ea u es o pa icle p o-
duc ion a e o pa icula in e es o be e i ied in Xe–Xe
collisions: (i) he low alue o he p/π a io wi h espec
o s a is ical- he mal model es ima es [17] and (ii) he ising
end o he φ/π a io om low o high mul iplici ies [9].
The i s obse a ion has led o se e al specula ions ang-
ing om he incomple e ea men o esonance eed-down
o a po en ial di e ence in chemical eeze-ou empe a u es
among di e en qua k la ou s [18–20] bu ound i s mos
likely explana ion in he inclusion o pion-nucleon phase
shi s wi hin he s a is ical- he mal model amewo k [21].
The second e ec p o ides s ic cons ain s o bo h he
canonical s a is ical- he mal app oach in which no ise is
p edic ed [9,22,23] as well as o models wi h only pa ial
s angeness equilib a ion in which a s eepe ise is expec ed
simila ly o he ba yon [22].
Mo eo e , he de ailed compa ison o spec al shapes in
Xe–Xe and Pb–Pb collisions a simila mul iplici ies p o-
ides heunique oppo uni y o in es iga e he hyd odynamic
expansion in sys ems o simila inal s a e cha ged pa icle
mul iplici y and di e en geome ical eccen ici y. Al eady
exis ing da a on he ellip ic low coe icien 2[24]showa
la ge di e ence in cen al collisions be ween he wo sys-
ems, as expec ed om he Glaube and hyd odynamical
models. In con as , he adial low and consequen ly he
0123456789().: V,- ol 123
584 Page 2 o 19 Eu . Phys. J. C (2021) 81:584
mean ans e se momen a a e expec ed o be compa able
be ween Xe–Xe and Pb–Pb a simila mul iplici ies [25]. The
es o hishypo hesisisoneo hesubjec so hismanusc ip .
In addi ion, he da a used in his a icle we e collec ed wi h a
lowe magne ic ield, hus allowing us o ex end he measu e-
men o pions o lowe ans e se momen a wi h espec o
p e ious s udies [26]. Fo his eason, hese da a may also be
o g ea ele ance o u u e s udies o po en ial condensa ion
phenomena a low ans e se momen a [27].
This a icle is o ganised as ollows. Sec ion 2desc ibes
he expe imen al se up and da a analysis as well as he sys-
ema ic unce ain ies. Resul s and compa isons wi h model
calcula ions a e discussed in Sec . 3. The summa y and con-
clusions a e gi en in Sec . 4.
2 Expe imen al appa a us, da a sample and analysis
The measu emen s epo ed in his a icle a e ob ained wi h
he ALICE cen al ba el which has ull azimu hal co e age
a ound mid apidi y in |η|<0.8 [28]. A de ailed desc ip-
ion o he ull ALICE appa a us can be ound in [29]. In
Oc obe 2017, o he i s ime a he LHC, Xe–Xe colli-
sions a √sNN =5.44 TeV we e eco ded by he ALICE
expe imen a an a e age ins an aneous luminosi y o abou
2×10−25 cm−2s−1and a had onic in e ac ion a e o 80–
150 Hz. In o al, he Xe–Xe da a sample consis s o abou
1.1×106minimum bias (MB) e en s passing he e en
selec ion desc ibed below. The MB in e ac ion igge is
p o ided by wo a ays o o wa d scin illa o s, named V0
de ec o s, wi h a pseudo apidi y co e age o 2.8<η<5.1
(V0A) and −3.7<η<−1.7(V0C)[30]. The V0 sig-
nal is p opo ional o he cha ged-pa icle mul iplici y and
is used o di ide he Xe–Xe sample in cen ali y classes
de ined in pe cen iles o he had onic c oss sec ion [31–33].
The analysis is ca ied ou in he cen ali y classes 0−5%,
5−10%, 10−20%, 20−30%, 30−40%, 40−50%, 50−60%,
60−70%, 70−90%. In o de o educe he s a is ical unce -
ain y, he φmeasu emen s a e ob ained in wide cen al-
i y classes 0−10%, 10−20%, 20−30%, 30−40%, 40−50%,
50−70%, 70−90%. The mos cen al (pe iphe al) collisions
a e conside ed in he 0−5% (70−90%) class. The 90−100%
cen ali ybin is no includedin he analysis sincei is a ec ed
by he con amina ion o elec omagne ic p ocesses (≈20%).
In addi ion, as desc ibed in [26,34], an o line selec ion o
he e en s is applied o emo e he beam-backg ound e en s.
I combines he V0 iming in o ma ion and he co ela ion
be ween he sum and he di e ence o imes measu ed in
each o he Ze o Deg ee Calo ime e s (ZDCs) posi ioned a
±112.5 m om he in e ac ion poin [29]. Due o he low
ins an aneous luminosi y (wi h an a e age collision p oba-
bili y pe bunch c ossing o μ≈0.0005), he p obabili y
o ha ing mo e han wo e en s pe collision igge was
su icien ly low ha he so-called e en pileup is conside ed
negligible.
The cen al ba el de ec o s a e loca ed inside a solenoidal
magne p o iding a maximum magne ic ield (B) o 0.5 T. A
magne ic ield o 0.2 T can be se when ope a ing he magne
in i s low B ield con igu a ion. The cen al ba el de ec o s
a e used o econs uc acks and measu e hei momen a,
as well as o pe o m pa icle iden i ica ion (PID). Those
exploi ed in his analysis a e ( om he in e ac ion poin ou -
wa ds) he Inne T acking Sys em (ITS) [28], he Time P o-
jec ion Chambe (TPC) [35] and he Time O Fligh (TOF)
de ec o [36]. Wi h espec o p e ious analyses [26], he low
amoun o collec ed da a makes i imp ac icable o pe o m
PID wi h he High Momen um Pa icle IDen i ica ion de ec-
o (HMPID) [37].
The ITS is equipped wi h six laye s o silicon de ec o s
made o h ee di e en echnologies: Silicon Pixel De ec-
o s (SPD, i s wo laye s om he in e ac ion poin ), Sil-
icon D i De ec o s (SDD, wo middle laye s) and Silicon
S ip De ec o s (SSD, wo ou e mos laye s). I allows he
econs uc ion o he collision e ex, he econs uc ion o
acks and he iden i ica ion o pa icles a low momen um
(p<1GeV/c) ia he measu emen o hei speci ic ene gy
loss (dE/dx). An ITS-only analysis can be pe o med by
using a dedica ed algo i hm o ea he ITS as a s andalone
acke , enabling he econs uc ion and iden i ica ion o low-
momen um pa icles ha do no each he TPC. The TPC,
a cylind ical gas de ec o equipped wi h Mul i-Wi e P o-
po ional Chambe s (MWPC), cons i u es he main cen al-
ba el acking de ec o and is also used o PID h ough he
dE/dxmeasu emen s in he gas. The dE/dxmeasu emen s
ob ained wi h he ITS and TPC de ec o s a e shown in Fig. 1.
The ime-o - ligh measu ed wi h he TOF, a la ge a ea cylin-
d ical de ec o based on Mul igap Resis i e Pla e Chambe
(MRPC) echnology, combined wi h he momen um in o -
ma ion measu ed in he TPC, is employed o iden i y pa i-
cles a low and in e media e momen a (5GeV/c).
The e en s analysed in his a icle a e chosen acco ding
o he selec ion c i e ia desc ibed in [26]. The p ima y e -
ex is de e mined om acks, including he ack segmen s
econs uc ed in he SPD. The posi ion along he beam axis
(z) o he e ex econs uc ed wi h he SPD segmen s and
o he one econs uc ed om acks a e equi ed o be com-
pa ible wi hin 0.5 cm wi h a esolu ion o he SPD one be e
han 0.25 cm. The posi ion o he p ima y e ex along z
is equi ed o be wi hin 10 cm om he nominal in e ac-
ion poin . These c i e ia ensu e a uni o m accep ance in he
pseudo apidi y egion |η|<0.8.
The esul s p esen ed in his wo k e e o p ima y pa -
icles, de ined as pa icles wi h a mean p ope li e ime o
τ>1cm/c ha a e ei he p oduced di ec ly in he in e ac-
ion o om decays o pa icles wi h τ<1cm/c, es ic ed
o decay chains leading o he in e ac ion poin [38]. To
123
Eu . Phys. J. C (2021) 81:584 Page 3 o 19 584
1−
10 1
)c (GeV/p
100
200
300
400
500
600
700
800
900
1000
m)
μ (keV/300x/dEITS d
e
μ
π
Kpd
ALICE
= 5.44 TeV
NN
s
Xe,−Xe
1−
10 1 10
)c (GeV/p
20
40
60
80
100
120
140
160
180
200
(a.u.)x/dETPC d
e
μ
πKp
d
ALICE
= 5.44 TeV
NN
sXe,−Xe
Fig. 1 Dis ibu ion o he dE/dxmeasu ed in he ITS (le ) and TPC
( igh ) de ec o s as a unc ion o he econs uc ed ack momen um in
Xe–Xe collisions a √sNN =5.44 TeV. The bands co esponding o he
signals o π±,K±,pandp a e well sepa a ed in he ele an momen um
anges. The good sepa a ion powe ob ained a low momen um is one
o he key ea u es o he measu emen s epo ed in his a icle
educe he con amina ion om seconda y pa icles om
weak decays and in e ac ions in he de ec o ma e ial, as well
as acks wi h w ongly associa ed hi s, simila selec ion c i-
e ia as desc ibed in [26,34] a e used and a e summa ised
below. T acks econs uc ed wi h bo h he TPC and he ITS
a e equi ed o c oss a leas 70 TPC eadou ows ou o a
maximum o 159 wi h a χ2no malised o he numbe o TPC
space poin s (“clus e s”), χ2/clus e , lowe han 4. The a io
be ween he numbe o clus e s and he numbe o c ossed
ows in he TPC has o be la ge han 0.8. An addi ional
cu on he ack geome ical leng h in he TPC iducial ol-
umeisusedasin[34]. T acks a e also equi ed o ha e a
leas wo hi s in he ITS de ec o ou o which a leas one
has o be in he SPD. In addi ion, o he ITS-only analysis,
he acks mus ha e a leas h ee hi s in he SDD + SSD
laye s. The χ2/clus e is also ecalcula ed cons aining he
ack o pass by he p ima y e ex and i is equi ed o be
lowe han 36. The same selec ion is also applied on he ITS
poin s o he ack: χ2
ITS/Nhi s
ITS <36. Fo he ITS-only anal-
ysis, his selec ion is es ic ed o χ2
ITS/Nhi s
ITS <2.5. Finally,
he acks a e equi ed o ha e a dis ance o closes app oach
(DCA) o he p ima y e ex along he beam axis lowe han
2cm.ApT-dependen selec ion is hen applied o he DCA
in he ans e se plane (DCAxy): |DCAxy|<7σDCAxy whe e
σDCAxy is he esolu ion on he DCAxy in each pTin e al.
Fu he mo e, he acks associa ed wi h decay p oduc s o
weakly decaying kaons (“kinks”) a e ejec ed. This selec ion
is no applied o kaons s udied ia hei kink decay opology.
The ack selec ion c i e ia o kaons and pions om kinks
will be desc ibed in he nex pa ag aph.
The Xe–Xe da a we e collec ed by ope a ing he de ec-
o in i s low B ield con igu a ion (B =0.2T).Thelowe
magne ic ield inc eases he p obabili y o low momen um
pa icles o c oss he ull de ec o hus ex ending he o e -
all accep ance and each o he analyses o lowe pT.This
allowed o he measu emen o pions down o 50 MeV/c
o he i s ime a he LHC wi h espec o pas publica ions
[2,26] whe e he lowes pT each was o 100 MeV/c. While
inc easing he pa icle de ec ion e iciencies a low momen a
wi h espec o he s anda d ield o 0.5 T, his con igu a ion
leads o a pT esolu ion o ITS-only acks ha is wo se by
almos a ac o 2 o π±,K
±, p and p in hei lowes pT
bin. As a consequence, o achie e a eliable PID, an un old-
ing echnique is used o ITS-only acks o accoun o he
esolu ion e ec s as i will be desc ibed in he nex sec ion.
On he con a y, he ime-o - ligh esolu ion and hence he
pe o mance o he TOF de ec o in e ms o PID sepa a ion
powe is una ec ed by he lowe magne ic ield. O e all, he
ime-o - ligh esolu ion is abou 60 ps in cen al collisions.
2.1 Pion, kaon and (an i-)p o on analysis
The pa icle iden i ica ion o π±,K
±, p and p elieson he
signals measu ed in he ITS, TPC and TOF de ec o s. This
p o ides a sepa a ion be ween di e en pa icle hypo he-
ses using ack-by- ack o s a is ical echniques. In addi-
ion, πand K a e measu ed by econs uc ing hei weak
decay (kink) opology [29]. Each o hese iden i ica ion ech-
niques is bes pe o ming in a gi en pT egion, as epo ed
in Table 1, and all oge he co e a wide pTin e al o up
123
584 Page 4 o 19 Eu . Phys. J. C (2021) 81:584
o5GeV/c. The inal spec a o each pa icle species a e
ob ained by combining he single analyses. The iden i ica-
ion o π±,K
±, p and p wi h ITS, TPC and TOF p oceeds by
e alua ing he di e ence be ween he measu ed and expec ed
signal (e.g. dE/dx, ime-o - ligh ) o a gi en species iin
e ms o numbe -o -sigmas (Nσ):
Nσ(i)=SignalMEAS −SignalEXP(i)
σ(i)(1)
whe e SignalEXP(i)is he expec ed signal and σ(i)i s
expec ed s anda d de ia ion ob ained unde each pa icle
mass hypo hesis, as desc ibed in [29,36]. A de ailed desc ip-
ion o such echniques and he measu ed sepa a ion powe
be ween he di e en pa icle species is shown o Pb–Pb
collisions in [26] and i is unchanged o his da a se .
ITS analysis TheITScanbeusedasas andalonelow-pTPID
de ec o hanks o he pa icle ene gy loss (dE/dx) measu ed
in i s ou ou e mos laye s [39]. To co ec o he de ec-
o esolu ion e ec s on he pa icle iden i ica ion o p1
GeV/c, a Bayesian un olding echnique is employed wi h he
RooUn old package [40]. The un olding o he momen um
dis ibu ion in dE/dxslices (1.1 keV/300 μm each) is pe -
o med wi h a ou -i e a ion p ocedu e whe e he ini ial p io
p obabili y is aken om he gene a ed momen um dis ibu-
ion in he Mon e Ca lo (MC) simula ed e en s wi h HIJING
[41]. A p ope co ec ion o de ec o ine iciencies and pa -
icle con amina ion is applied ollowing he p esc ip ion in
[40]. The un olded momen um (pTRUE) co esponding o he
maximum o he condi ional p obabili y P(pTRUE |pMEAS)
o a gi en measu ed momen um pMEAS is conside ed o
he e alua ion o he expec ed signal in he Nσapp oach (see
Eq. (1)).Basedon his, heplane(pTRUE;dE/dx) is di ided
in o iden i ica ion egions whe e each poin is assigned a
unique pa icle iden i y. The iden i y o a ack is assigned
basedon hedi e ence be ween he measu ed dE/dxand he
one compu ed unde each mass hypo hesis. The hypo hesis
which gi es he smalles dis ance is used, he eby emo ing
he sensi i i y o he pa ame e isa ion o he dE/dx esolu-
ion. A u he selec ion |Nπ
σ|<2 ejec s elec ons in he
pion iden i ica ion.
To calcula e he un olded pTdis ibu ions ( s pTRUE
T), he
Bayesianun oldingis also applied o he aw pMEAS
Tdis ibu-
ions o each species. In his case, he ini ial p io p obabili y
o he un olding is aken om he gene a ed pTdis ibu ions
o each species in he MC and he numbe o i e a ions is kep
o ou so as o minimize he s a is ical luc ua ions (di e -
en numbe s a e conside ed o he sys ema ic unce ain y
e alua ion).
Wi h his me hod i is possible o iden i y π±,K
±, p and
p in he ollowing pT anges, espec i ely: 0.05−0.6GeV/c,
0.2−0.5GeV/cand 0.3−0.6GeV/c. This also allows o he
educ ion o he con amina ion due o o he pa icle species.
Fo he i s ime a he LHC, hanks o he low magne ic ield
con igu a ion he pT each o he pion spec a is ex ended
down o 50 MeV/cwi h a con amina ion om elec ons
o abou 30%. To his pu pose, a de ailed s udy in he low
momen um egion was ca ied ou in di e en apidi y in e -
als o e i y he s abili y o he measu emen (as i will be
explained in Sec . 2.3).
TPC and TOF analyses The iden i ica ion wi h he TPC
and TOF de ec o s mos ly ollows he p ocedu e de eloped
in [26] wi h some adap a ions. In bo h cases, he esponse
o he PID signal was uned o he lowe magne ic ield
con igu a ion. The aw yield o pa icles is ex ac ed in each
pTin e al ia a s a is ical un olding. In pa icula , o he
TOF analysis empla es ob ained wi h a da a-d i enapp oach
a e used. An addi ional empla e is used o ake in o accoun
he signal componen due o he TPC-TOF ack misma ch.
The excellen PID pe o mance achie ed wi h bo h de ec o s
allowed a con inuous sepa a ion o pions om kaons and
kaons om (an i-)p o ons in a wide in e al o pTas epo ed
in Table 1.
Kink analysis Cha ged kaons and pions can also be iden i-
ied by econs uc ing hei weak decay opology (kink opol-
ogy) de ined as seconda y e ices wi h wo acks (mo he
and daugh e ) ha ing he same cha ge. The kink opology is
analysed inside he TPC olume wi hin a adius o 110–220
cm. De ails abou he kaon iden i ica ion algo i hm based on
he kink opology can be ound in [5,26,29,42]. In his a i-
cle, he iden i ica ion o pions ia hei kink decay opology
is epo ed o he i s ime a he LHC.
The iden i ica ion o kaons om kink opology and hei
sepa a ion om pion decays is based on he wo-body decay
kinema ics. The me hod allows o he ex ac ion o kaon
and pion spec a on a ack-by- ack basis. Bo h pa icles
decay in o μ+νμwi h b anching a ios (B.R.) o 63.55% (K)
and 99.99% (π)[43]. Fo his decay channel, he ans e se
momen um o he cha ged daugh e pa icle wi h espec o
he di ec ion o he mo he ack (qT), has an uppe limi
o 236 MeV/c o kaons and 30 MeV/c o pions. Taking
in o accoun ha he uppe limi o qT o he decay K±→
π±+π0(wi h B.R.=20.66% [43]) is 205 MeV/c,an
e ec i e sepa a ion o kaons om pions can be achie ed by
selec ing kinks wi h qT>40 MeV/c. Fu he selec ions
a e applied o each a pu i y o kaons highe han 95%: (i)
qT>120 MeV/cin o de o disca d pion and 3-body kaon
decays, (ii) a kink adius in he ans e se plane be ween
110 and 205 cm, (iii) a leas 20 TPC clus e s o he mo he
ack, (i ) a decay angle g ea e han 2oin o de o emo e
ake kinks om pa icles ha a e w ongly econs uc ed as
wo sepa a e acks, and ( ) a kink decay angle, a a gi en
mo he momen um, be ween he maximum decay angle o
pion o muon (μ+νμdecay) and he maximum decay angle
o kaon o muon (μ+νμdecay). Finally, iden i ied kaons
123

Eu . Phys. J. C (2021) 81:584 Page 5 o 19 584
Table 1 T ans e se momen um
in e als and he co esponding
PID me hods o pions, kaons
and (an i-)p o ons
Technique π±(GeV/c)K
±(GeV/c)pandp (GeV/c)
ITS 0.05–0.6 0.2–0.5 0.3–0.6
TPC 0.35–0.6 0.25–0.35 0.55–0.75
TOF 0.45–5.0 0.45–4.0 0.65–5.0
Kinks 0.3–0.95 0.3–5.0 –
om kinks a e accep ed i he mo he ack is ound o ha e a
dE/dxwi hin 3.5σa ound he expec ed Be he–Bloch alue
o kaons.
The cha ged pions ha a e iden i ied ia hei kink decay
opology show a pu i y highe han 97%. Simila selec-
ion c i e ia as o kaons a e used excep o 10 <qT<
40 MeV/c( he mos e ec i e cu ) and wi h he equi emen
o a decay angle smalle han he maximum decay angle o
π→μ+νμ. The di e ence in he qTselec ion o kaon
and pion iden i ica ion is due o hei di e en decay angles
o a muon a equal mo he momen um. The maximum decay
angleo a kinkmo he ack wi h momen um p=1.5GeV/c
is 2o o he pion o muon decay while 50o o he kaon o
muon decay, because o he mass di e ence o he mo he
pa icles. This ea u e es ic s he pion iden i ica ion below
p=1.5GeV/c.
2.1.1 Co ec ions o e iciency and eed-down
The pTdis ibu ions o π±,K
±, p and p a e ob ained by
co ec ing he aw spec a o PID e iciency, misiden i ica-
ion p obabili y, accep ance and acking e iciencies as pe -
o med in [26] o he ITS, TPC, TOF and kink analyses.
The e iciencies a e ob ained om Mon e Ca lo simula ed
e en s gene a ed wi h HIJING. The p opaga ion o pa icles
h ough he de ec o is simula ed wi h he GEANT3 ans-
po code [44] whe e he de ec o cha ac e is ics and da a-
aking condi ions a e p ecisely ep oduced. Thanks o he
lowe magne ic ield o he Xe–Xe da a sample, a acking
e iciency o abou 2% (2.4%) is eached a he lowes pT
poin (pT=50MeV/c) o pions in he mos cen al (pe iph-
e al) bin compa ed o an e iciency lowe han 1‰ a ull
ield. I is known [2,26,45] ha he ene gy loss o low-pT
p in he de ec o ma e ial and he c oss sec ion o low-pT
K−a e no well ep oduced in GEANT3. Fo his eason, a
co ec ion o he e iciency is es ima ed using GEANT4 [46]
and FLUKA [47], espec i ely, in which hese p ocesses a e
ep oducedmo eaccu a ely.Theco ec ionsamoun oabou
10% and 4% o p and K−, espec i ely, in he lowes pTbin
(see Table 1). The PID e iciency and he misiden i ica ion
p obabili y a e es ima ed in he simula ion by equi ing he
simula ed da a o ep oduce he eal PID esponse o each
de ec o included in his analysis.
The aw dis ibu ions a e u he co ec ed o he con-
ibu ion o seconda y pa icles ( eed-down) mainly due o
weak decays o K0
S(a ec ing π±), and +(a ec ing p
and p). Seconda y p o ons coming om he de ec o ma e-
ial a e also sub ac ed om he aw spec um. The es ima-
ion o his co ec ion ac o is da a-d i en since he e en
gene a o s unde es ima e he s angeness p oduc ion and,
as al eady men ioned, he anspo codes do no p o ide
a p ecise desc ip ion o he in e ac ion o low-pTpa icles
wi h he de ec o ma e ial. Fo each analysis, he econ-
s uc ed DCAxy dis ibu ions o each pa icle species a e
i ed in each pTin e al wi h h ee con ibu ions (as em-
pla es) ex ac ed om he Mon e Ca lo simula ion: p ima y
pa icles, seconda y pa icles om weak decays o s ange
had ons and seconda y pa icles p oduced in he in e ac ion
wi h he de ec o ma e ial, simila ly o wha is epo ed in
[2,26]. Finally, he spec a a e no malized o he o al num-
be o e en s analysed in each cen ali y class. The spec a
in he ex ended pT ange a e ob ained by combining hose
ob ained wi h he single iden i ica ion echniques. In he pT
in e als whe e mo e analyses o e lap, he combina ion is
ca ied ou by pe o ming an a e aged mean using he single
sys ema ic unce ain ies as weigh s.
2.2 φmeson analysis
The φmeson signal is econs uc ed ia in a ian mass anal-
ysis by exploi ing he decay channel in o cha ged kaons,
φ→K+K−(B.R. = 0.492 ±0.005 [43]). The analysis
ollows a consolida ed echnique desc ibed ex ensi ely in
[6,7,11]. Candida e kaons a e iden i ied based on he a i-
able de ined by Eq. (1) o hedE/dxsampled in he TPC
(NTPC
σ) o he ime-o - ligh measu ed by he TOF (NTOF
σ).
Mo ep ecisely, a ack associa ed wi h ahi in heTOF de ec-
o is iden i ied as a K i |NTOF
σ|<3 and |NTPC
σ|<5. I a
ack does no each he TOF de ec o and no ime-o - ligh
measu emen is a ailable, only he in o ma ion o he TPC
is used by equi ing ha |NTPC
σ|<2 o pT>0.4GeV/c,
|NTPC
σ|<3 o 0.3<pT<0.4GeV/c, and |NTPC
σ|<5
o pT<0.3GeV/c. Wi hin each e en , iden i ied kaons
a e combined in opposi ely-cha ged pai s (“unlike-sign”) o
ex ac he in a ian mass (MKK) dis ibu ion o he signal.
To es ima e he backg ound om unco ela ed pai s, an e en
mixing echnique is used, which consis s in building he
in a ian mass dis ibu ion o K+K−pai s om i e di e en
e en swi h simila cen ali y(wi hin 5%)anda simila e ex
123
584 Page 6 o 19 Eu . Phys. J. C (2021) 81:584
posi ion along he beam axis (wi hin 1 cm). Only same-e en
and mixed-e en pai s wi h apidi y |y|<0.5 a e selec ed.
The mixed-e en backg ound is no malised o he in eg al
o he unlike-sign dis ibu ion in he in a ian mass in e al
1.07 ≤MKK ≤1.1GeV/c2and hen sub ac ed. The esul -
ing dis ibu ion exhibi s a clea peak cen e ed a he nominal
mass o φ[43], on op o a low esidual backg ound. The
φsignal peak is i ed wi h a Voig ian unc ion (as in [48]),
which is he con olu ion o a B ei –Wigne , desc ibing he
cha ac e is ic shape o he esonance s a e, and a Gaussian,
aking in o accoun he de ec o esolu ion. The esonance
wid his ixed o henominal alueo φ=4.26MeV/c2[43],
whe eas he mass and he mass esolu ion σφa e le as ee
i pa ame e s. The mass esul ing om he i is consis en
wi h he nominal alue o he φmass epo ed in [43]. The σφ
pa ame e anges om≈1.5MeV/c2a pT=0.5−1GeV/c
o ≈2.5 MeV/c2a pT=10GeV/c, and i is consis en wi h
he mass esolu ion ex ac ed om Mon e Ca lo simula ions
o he ull de ec o se up and econs uc ion chain. The esid-
ual backg ound is pa ame e ised wi h a linea unc ion. The
i is pe o med in he ange 0.994 <MKK <1.07 GeV/c2.
Thisp ocedu e is epea ed o each pTand cen ali y in e al.
The pT-di e en ial yields ob ained wi h he desc ibed
p ocedu e a e co ec ed o e iciency and accep ance, as
desc ibed in [11]. The co ec ions a e ob ained om a Mon e
Ca lo simula ion whe e e en s a e gene a ed wi h HIJING
[41] and pa icles a e anspo ed h ough a de ailed simula-
ion o he ALICE de ec o wi h he GEANT3 anspo code
[44]. The selec ion c i e ia o φcandida es a e he same in
Mon e Ca lo and da a.
2.3 Sys ema ic unce ain ies
The calcula ion o he sys ema ic unce ain ies ollows he
p ocedu e pe o med al eady o p e ious analyses [2,7,26,
42,48].The main sou ces o sys ema ic unce ain ies o each
pa icle species a e summa ised in Table 2(π±,K
±, p and
p) and in Table 3(φ).
The main sou ces o sys ema ic unce ain y a ec ing
his analysis a e: PID, eed-down co ec ion, he impe ec
desc ip ion o he ma e ial budge in he Mon e Ca lo simula-
ion, he knowledge o he had onic in e ac ion c oss sec ion
in he de ec o ma e ial [26], he ITS-TPC [34] (accoun ed
wice o he decay daugh e s o he φ) and TPC-TOF ma ch-
ing e iciencies, he ack selec ion, he un olding i e a ions
and he apidi y selec ion o he ITS. The unce ain ies o
ack selec ion e e o he quali y equi emen s based on he
numbe o c ossed ows in he TPC, he numbe o clus e s
in he ITS, he DCAxy and DCAz, and he χ2/NDF o he
econs uc ed acks. To es ima e hese unce ain ies, a a i-
a ion o he s anda d selec ion c i e ia is pe o med and he
a io be ween he co ec ed spec a wi h modi ied selec ion
c i e ia and he ones wi h s anda d equi emen s is calcu-
la ed, as pe o med in [26]. Fo he unce ain y ela ed o he
numbe o i e a ions in he Bayesian un olding o he ITS
analysis, a simila app oach is ollowed whe e he numbe
o i e a ions is changed om 4 (de aul ) o 3, 5, 7 and 9. The
unce ain ies ela ed o PID a e e alua ed by compa ing di -
e en echniques (e.g. s a is ical un olding e sus ack-by-
ack Nσselec ion). In addi ion, o he φ, a de ailed s udy o
he yield ex ac ion p ocedu e was ca ied ou by in es iga -
ing he e ec o a ia ions in he signal shape pa ame e s, he
backg ound shape and he i ange, as pe o med in [48]. The
unce ain ies o he de ec o ma e ial budge a e es ima ed
by changing he ma e ial budge in he simula ion wi h he
GEANT3 anspo code by ±7% as in [26,49]. The unce -
ain y o he had onic in e ac ion c oss sec ion is calcula ed
by compa ing he e iciencies in di e en anspo codes
(GEANT3, GEANT4, FLUKA) ollowing he p esc ip ion
gi en in [50]. Finally, he unce ain ies on he eed-down a e
de e mined by a ying he ange o he empla e i o he
DCAxy dis ibu ions.
Fo he ITS analysis, a sys ema ic unce ain y is in o-
duced o ake in o accoun he shi o he clus e posi ions
caused by he Lo en z o ce (E×Be ec ), as desc ibed
in [26]. Fo he kink analysis, he sys ema ic unce ain ies
a e es ima ed by compa ing he s anda d spec a wi h he
ones ob ained by a ying he selec ion c i e ia on he decay
p oduc ans e se momen um, he minimum numbe o TPC
clus e s and he kink adius.
Finally, he sys ema ic unce ain ies on he e y low pT
egion o he spec a a e highe compa ed o p e ious analy-
ses [2,26] because o he lowe momen um esolu ion in he
educed magne ic ield. None heless, he unce ain y on he
pion measu emen below 100 MeV/cis below 12%. In addi-
ion, he limi ed s a is ics o he Xe–Xe da a sample es ic s
he de ec o s and echniques ha can con ibu e o he PID
a highe momen a, excluding he HMPID de ec o and he
TPC ene gy loss measu emen in he ela i is ic ise egion.
This yields o e all la ge unce ain ies wi h espec o p e-
ious ALICE measu emen s in o he collision sys ems. A
3GeV/c he unce ain ies a e app oxima ely wice as la ge
wi h espec o [26] o π±,K
±, p and p.
3 Resul s and discussion
3.1 T ans e se momen um spec a
The π±,K
±,p,p and φpTspec a ob ained a e all co -
ec ions a e shown o cen al and pe iphe al collisions in
Fig. 2. Each spec um is indi idually i ed wi h a Blas -
wa e unc ion [51], shown wi h dashed lines. The in eg a ed
yield dN/dyand he mean ans e se momen a pTa e
calcula ed om he measu ed spec a and he ex apola-
ion o he Blas -wa e unc ions in he unmeasu ed egions.
123
Eu . Phys. J. C (2021) 81:584 Page 7 o 19 584
Table 2 Main sou ces and alues o he ela i e sys ema ic unce ain-
ies (exp essed in %) o he pT-di e en ial yields o π±,K
±,pandp
ob ained in he analysis o Xe–Xe collisions. The i s sec ion is com-
mon o all he analyses, he analysis speci ic unce ain ies a e lis ed sep-
a a ely. When wo alues a e epo ed, hey co espond o he lowes
and highes pTbin espec i ely, conside ing he maximum con ibu-
ion among he a ious cen ali y classes. I only one alue is epo ed,
he sys ema ic unce ain y is no pT-dependen . Fo ce ain sou ces,
he cen ali y is speci ied when a la ge dependence on cen ali y is
obse ed. The maximum o al sys ema ic unce ain ies (among all cen-
ali y classes) a e shown. The o al unce ain y e e s o he unce ain y
o he combined esul s (see ex )
E ec π±(%) K±(%) p and p(%)
ITS−TPC ma ching e iciency (0−5%) 2.2−0.4 2.2−0.4 2.2−0.4
ITS−TPC ma ching e iciency (40−50%) 3.0−1.2 3.0−1.2 3.0−1.2
ITS−TPC ma ching e iciency (70−90%) 2.8−0.6 2.8−0.6 2.8−0.6
Ma e ial budge 1.6−0.2 1.3−0.4 2.9−0.1
Had onic in e ac ion c oss sec ion 2.5−2.4 2.7−1.8 4.6
ITS analysis
PID 1.4−3.1 1.4−7.7 1.2−0.7
T ack selec ion 4.7−4.4 6.0−6.7 9.8−7.9
E×B3.0 3.0 3.0
Un olding i e a ions 5.5−2.2 6.1−5.2 13.7−2.3
Rapidi y selec ion 7.0−3.0 3.0 10.0
Feed-down co ec ion 3.2−3.2 3.0−3.0 3.0−3.0
Ma ching e iciency (0−5%) 1.2 1.2 1.2
Ma ching e iciency (40−50%) 0.5 0.5 0.5
Ma ching e iciency (70−90%) 2.0 2.0 2.0
Had onic in e ac ion c oss sec ion (ITS acks) 3.0−0.3 2.7−1.5 13.3−5.6
TPC analysis
PID (0−5%) 14.−14.4 3.3−15.0 4.3−19.5
PID (40−50%) 5.4−5.3 2.0−7.4 0.8−9.5
PID (70−90%) 3.9−4.6 2.1−6.6 1.0−4.8
T ack selec ion 0.4−1.5 5.0−6.0 3.8−3.0
Feed-down co ec ion 0.5 −0.8−9.7
TOF analysis
PID 3.0−12.0 3.0−18.0 2.0−20.0
T ack selec ion 1.5 1.5 1.8
Ma ching e iciency 1.2−54.5−5.0 5.3−5.0
Feed-down co ec ion 0.5 −9.7−0.4
Kink analysis
PID + econs uc ion e iciency (0−5%) 2.6 1.7−6.0 −
PID + econs uc ion e iciency (40−50%) 2.6 1.0−4.4 −
PID + econs uc ion e iciency (70−90%) 1.6 2.7−4.7 −
Con amina ion (0−5%) 1.0−4.0 0.5−5.3 −
Con amina ion (40−50%) 1.0−2.0 0.5−3.2 −
Con amina ion (80−90%) 1.0−2.0 0.5−3.0 −
To al 11.1−21.9 9.0−10.0 22.4−10.5
As pe o med in p e ious analyses [2,26], he sys ema ic
unce ain ies o bo h dN/dyand pTa e e alua ed by
shi ing he da a poin s up and down wi hin hei sys em-
a ic unce ain y o ob ain he so es and ha des spec a.
An addi ional con ibu ion is gi en by he ex apola ion o
pT=0GeV/cwhe e di e en unc ions (mT-exponen ial,
Fe mi-Di ac, Bose-Eins ein, Bol zmann) we e used o he
calcula ion. The unce ain y on he ex apola ion o he mos
cen al collisions is ound o be ∼1% o pions and kaons,
∼5% o p o ons and ∼2% o φ.
As al eady obse ed in Pb–Pb and also in small collision
sys ems [1,9,26], he pT ises wi h inc easing cen ali y
and mul iplici y (dNch/dη). This ha dening is signi ican ly
mo ep onounced o hea ie pa icles.Fo ins ance, hemax-
123
584 Page 8 o 19 Eu . Phys. J. C (2021) 81:584
Fig. 2 pTdis ibu ions o π±,
K±,p,p, φas measu ed in
cen al (le ) and pe iphe al
( igh ) Xe–Xe collisions a
√sNN =5.44 TeV. The
s a is ical and sys ema ic
unce ain ies a e shown as e o
ba s and boxes a ound he da a
poin s
01234567
)c (GeV/
T
p
6−
10
5−
10
4−
10
3−
10
2−
10
1−
10
1
10
2
10
3
10
-1
)c) (GeV/yd
T
p/(dN d
e
N 1 /
= 5.44 TeV
NN
sXe−Xe
ALICE
5%−0
)
0
10× (
-
π +
+
π
)
-1
10× (
-
+ K
+
K
)
-2
10× (pp +
10%−0
)
-3
10× (φ
01234567
)c (GeV/
T
p
90%−70
)
1
10× (
-
π +
+
π
)
0
10× (
-
+ K
+
K
)
-1
10× (pp +
)
-2
10× (φ
Indi idual blas -wa e i
Table 3 Main sou ces and alues o he ela i e sys ema ic unce ain-
ies (exp essed in %) o he pT-di e en ial yields o φob ained in he
analysis o Xe–Xe collisions. When wo alues a e epo ed, hey co -
espond o he lowes and highes pTbin espec i ely, conside ing he
maximum con ibu ion among he a ious cen ali y classes. I only one
alue is epo ed, he sys ema ic unce ain y is no pT-dependen . The
maximum o al sys ema ic unce ain ies (among all cen ali y classes)
a e shown
E ec φ(%)
B.R. 1
ITS−TPC ma ching e iciency 6.4−11
T ack cu s 2.2−4
PID 2−12
Had onic in e ac ion 2.2−0
Ma e ial budge 1.0−0
Yield ex ac ion 5−15
To al 10−20
imum o he p spec um shi s om pT≈0.8GeV/cin
pe iphe al o pT≈1.4GeV/cin cen al collisions, while
o pions he shi is much smalle . This ea u e is gene ally
conside ed as a consequence o he adial expansion o he
sys em. The compa ison o pTas a unc ion o cha ged-
pa icle mul iplici y o Pb–Pb and Xe–Xe collisions, shown
in Fig. 3, clea ly demons a es ha his e ec is en i ely
d i en by he mul iplici y and no by he collision geome-
y. Mos no ably, he pT alues o p o ons and φdi e in
pe iphe al (low dNch/dη) Xe–Xe and Pb–Pb collisions, bu
each simila alues in semi-cen al and cen al collisions.
This beha iou is expec ed due o he small mass di e ence
2
10 3
10
| < 0.5
η
|
〉
η
/d
ch
Nd〈
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
)c (GeV/〉
T
p〈
-
π+
+
π-
+K
+
K pp+ φ
ALICE
= 5.02 TeV (open symbols)
NN
sPb−Pb
= 5.44 TeV (solid symbols)
NN
sXe−Xe
Fig. 3 Mean pTo pions, kaons, (an i-)p o ons and φas a unc ion o
hecha ged-pa iclemul iplici ydensi yinXe–Xecollisionsa √sNN =
5.44 TeV and Pb–Pb collisions a √sNN =5.02 TeV [11,26]. The
s a is icalandsys ema icunce ain ies a e shown as e o ba sand boxes
a ound he da a poin s
o hese wo pa icles i he spec al shape is mo e and mo e
domina ed by adial low wi h inc easing cen ali y.
The mass-dependen adial low na u ally explains in cen-
al collisions he so-called ba yon- o-meson enhancemen a
low o in e media e pT(5GeV/c) obse ed in he ligh -
la ou sec o [26]. This e ec is seen in Fig. 4whe e he p/π
123
Eu . Phys. J. C (2021) 81:584 Page 15 o 19 584
H. Hillemanns35, C. Hills130 , B. Hippoly e139 , B. Hohlwege 107 , J. Hone mann146 , G. H. Hong149, D. Ho ak38,
S. Ho nung110 , R. Hosokawa15,P.H is o
35, C. Huang79, C. Hughes133, P. Huhn69, T. J. Humanic99 , H. Hushnud113,
L. A. Huso a146, N. Hussain43, D. Hu e 40 , J. P. Iddon35,130, R. Ilkae 112, H. Ilyas14, M. Inaba136, G. M. Innocen i35,
M. Ippoli o 90,A.Isako
38,97, M. S. Islam113, M. I ano 110, V. I ano 100, V. Izuchee 93, B. Jacak81, N. Jacazio35,55 ,
P. M. Jacobs81 , S. Jadlo ska120, J. Jadlo sky120, S. Jaelani63 , C. Jahnke124, M. J. Jakubowska144 , M. A. Janik144 ,
T. Janson75, M. Je cic101, O. Je ons114,M.Jin
128, F. Jonas98,146, P. G. Jones114, J. Jung69, M. Jung69, A. Junique35,
A. Jusko114,P. Kalinak65 ,A.Kalwei 35 ,V. Kaplin95 ,S.Ka 7,A. Ka asu Uysal78 ,D. Ka a o ic101,O. Ka a iche 64,
T. Ka a iche a64 , P. Ka czma czyk144 , E. Ka peche 64, A. Kazan se 90, U. Kebschull75, R. Keidel48,M.Keil
35,
B. Ke ze 44, Z. Khabano a92, A. M. Khan7, S. Khan16, A. Khanzadee 100, Y. Kha lo 93 , A. Kha un16 , A. Khun ia121 ,
B. Kileng37,B.Kim
62,D.Kim
149,D.J.Kim
129 , E.J.Kim
74 ,H.Kim
17 ,J.Kim
149,J.S.Kim
42,J.Kim
106 ,
J. Kim149,J.Kim
74,M.Kim
106 ,S.Kim
18,T.Kim
149,T.Kim
149, S. Ki sch69,I.Kisel
40 ,S.Kisele
94 ,
A. Kisiel144,J.L.Klay
6, J. Klein35,60 , S. Klein81 , C. Klein-Bösing146 , M. Kleine 69, T. Klemenz107,
A. Kluge35, A. G. Knospe128, C. Kobdaj119 , M. K. Köhle 106, T. Kollegge 110, A. Kond a ye 76 , N. Kond a ye a95,
E. Kond a yuk93, J. Konig69, S. A. Konigs o e 107, P. J. Konopka2,35 , G. Ko nako 144 , S. D. Ko yciak2, L. Koska120,
O. Ko alenko87, V. Ko alenko116 ,M.Kowalski
121, I. K álik65 ,A.K a ˇcáko á39,L.K eis
110, M. K i da114,65,
F. K izek97 , K. K izko a Gajdoso a38, M. K oesen106, M. K üge 69, E. K yshen100, M. K zewicki40,V.Kuˇce a35,
C. Kuhn139,P.G.Kuije
92 , T. Kumaoka136, L. Kuma 102 , S. Kundu88, P. Ku ash ili87, A. Ku epin64, A. B. Ku epin64 ,
A. Ku yakin112, S. Kushpil97 , J. K apil114, M.J.Kweon
62,J.Y.Kwon
62 ,Y.Kwon
149, S. L. La Poin e40 ,
P. La Rocca27 ,Y.S.Lai
81, A. Lak a hok119, M. Lamanna35, R. Langoy132, K. Lapidus35, P. La iono 53, E. Laudi35,
L. Lau ne 35, R. La icka38 , T. Laza e a116,R.Lea
24 ,J.Lee
136,S.Lee
149, J. Leh bach40, R. C. Lemmon96 ,
I. León Monzón123 ,E.D.Lesse
19 , M. Le ich35, P. Lé ai147,X.Li
11,X.L.Li
7,J.Lien
132, R. Lie a a114,B.Lim
17,
S. H. Lim17 , V. Lindens u h40, A. Lindne 49, C. Lippmann110,A.Liu
19,J.Liu
130, I. M. Lo nes21, V. Logino 95,
C. Loizides98 , P. Lonca 36, J. A. Lopez106 , X. Lopez137 , E. López To es8, J. R. Luhde 146, M. Luna don28 ,
G. Lupa ello61 ,Y.G.Ma
41, A. Mae skaya64, M. Mage 35, S. M. Mahmood20, T. Mahmoud44,A.Mai e
139 ,
R. D. Majka148,e, M. Malae 100, Q. W. Malik20, L. Malinina76,c,D.Mal’Ke ich
94, N. Mallick51, P. Malzache 110,
G. Mandaglio33,57, V. Manko90 , F. Manso137, V. Manza i54 ,Y.Mao
7, J. Ma eš67, G. V. Ma gaglio i24 ,
A. Ma go i55 ,A.Ma ín
110 ,S.Ma ium
108,C.Ma ke
122 , M. Ma qua d69, N. A. Ma in106, P. Ma inengo35,
J. L. Ma inez128, M. I. Ma ínez46, G. Ma ínez Ga cía118, S. Masciocchi110 , M. Mase a25 , A. Masoni56 ,
L. Massac ie 79 , A. Mas ose io54,141 , A.M.Ma his
107 , O. Ma onoha82, P. F. T. Ma uoka124, A. Ma yja121 ,
C. Maye 121 , A. L. Mazuecos35, F. Mazzaschi25, M. Mazzilli35,54, M. A. Mazzoni59 , A. F. Mechle 69, F. Meddi22 ,
Y. Melikyan64 , A. Menchaca-Rocha72, C. Mengke28,7, E. Meninno30,117 , A. S. Menon128,M.Me es
13, S. Mhlanga127,
Y. Miake136, L. Michele i25, L. C. Miglio in138, D. L. Mihaylo 107, K. Mikhaylo 76,94 , A.N.Mish a
147,70,
D. Mi´skowiec110,A. Modak4,N. Mohammadi35,A. P. Mohan y63,B. Mohan y88 ,M. Mohisin Khan16,Z. Mo a co a91 ,
C. Mo dasini107, D. A. Mo ei a De Godoy146, L. A. P. Mo eno46, I. Mo ozo 64,A.Mo sch
35,T.M nja ac
35,
V. Mucci o a53 , E. Mudnic36, D. Mühlheim146, S. Muhu i143, J. D. Mulligan81 , A. Mulli i23, M. G. Munhoz124,
R. H. Munze 69 , H. Mu akami135,S.Mu ay
127 ,L.Musa
35,J.Musinsky
65, C.J.Mye s
128, J. W. My cha144,
B. Naik50,R.Nai
87 , B. K. Nandi50, R. Nania55 , E. Nappi54 ,M.U.Na u
14 , A. F. Nassi pou 82, C. Na ass133 ,
S. Naza enko112, A. Neagu20, L. Nellen70 , S. V. Nesbo37, G. Nesko ic40 ,D.Nes e o
116, B. S. Nielsen91 ,
S. Nikolae 90, S. Nikulin90, V. Nikulin100, F. No e ini55 ,S.Noh
12 , P. Nomokono 76,J.No man
130, N. No i zky136,
P. Nowakowski144, A. Nyanin90, J. Nys and21, M. Ogino84,A.Ohlson
82, J. Oleniacz144 , A. C. Oli ei a Da Sil a133 ,
M. H. Oli e 148, A. Onne s ad129, C. Oppedisano60 , A. O iz Velasquez70 ,T.Osako
47, A. Oska sson82,
J. O winowski121, K. Oyama84, Y. Pachmaye 106 , S. Padhan50, D. Pagano142 ,G.Pai´c70, A. Palasciano54,J.Pan
145 ,
S. Panebianco140 , P. Pa eek143 ,J.Pa k
62, J. E. Pa kkila129 ,S.Pa ma
102, S. P. Pa hak128, B. Paul23 , J. Pazzini142,
H. Pei7, T. Pei zmann63 , X. Peng7, L. G. Pe ei a71 , H. Pe ei a Da Cos a140, D. Pe esunko90, G. M. Pe ez8,
S. Pe in140, Y. Pes o 5, V. Pe áˇcek38, M. Pe o ici49, R. P. Pezzi71, S. Piano61 , M. Pikna13, P. Pillo 118 ,
O. Pinazza35,55 ,L.Pinsky
128, C. Pin o27, S. Pisano53,M.Płosko´n81, M. Planinic101, F. Plique 69, M. G. Poghosyan98,
B. Polich chouk93, N. Poljak101 , A. Pop49 , S. Po eboeu -Houssais137 , J. Po e 81 , V. Pozdniako 76,S.K.P asad
4,
R. P eghenella55 ,F.P ino
60 , C. A. P uneau145, I. Pshenichno 64 , M. Puccio35 ,S.Qiu
92 , L. Quaglia25,
R. E. Quishpe128, S. Ragoni114, A. Rako oza ind abe140, L. Ramello32 ,F.Rami139,S.A.R.Rami ez
46,A.G.T.Ramos
34,
R. Raniwala104 , S. Raniwala104, S. S. Räsänen45 ,R.Ra h
51, I. Ra asenga92 , K. F. Read98,133 , A. R. Redelbach40,
K. Redlich87,d, A. Rehman21, P. Reichel 69, F. Reid 35 , R. Ren o d 69, Z. Rescako a39, K. Reyge s106 , A. Riabo 100,
V. Riabo 100, T. Riche 82,91, M. Rich e 20, P. Riedle 35, W. Riegle 35, F. Riggi27 , C. Ris ea68, S. P. Rode51,
M. Rod íguez Cahuan zi46, K. Røed20, R. Rogale 93, E. Rogochaya76 , T. S. Rogoschinski69, D. Roh 35 , D. Röh ich21,
123

584 Page 16 o 19 Eu . Phys. J. C (2021) 81:584
P. F. Rojas46, P.S.Roki a
144, F. Ronche i53 , A. Rosano33,57, E. D. Rosas70, A. Rossi58 , A. Ro ondi29 ,
A. Roy51,P.Roy
113, N. Rubini26, O. V. Rueda82,R.Rui
24 , B. Rumyan se 76,A.Rus amo
89, E. Ryabinkin90,
Y. Ryabo 100, A. Rybicki121, H. Ry konen129, W. Rzesa144, O. A. M. Saa imaki45, R. Sadek118, S. Sado sky93,
J. Sae e21, K. Ša aˇ ík38 , S. K. Saha143, S. Saha88, B. Sahoo50 , P. Sahoo50, R. Sahoo51 , S. Sahoo66, D. Sahu51,
P. K. Sahu66, J. Saini143, S. Sakai136, S. Sambyal103 , V. Samsono 95,100,e, D. Sa ka 145, N. Sa ka 143, P. Sa ma43,
V. M. Sa i107, M.H.P.Sas
63,148 , J. Schambach98,122, H. S. Scheid69 , C. Schiaua49, R. Schicke 106, A. Schmah106,
C. Schmid 110, H. R. Schmid 105, M. O. Schmid 106 , M. Schmid 105, N. V. Schmid 69,98 , A. R. Schmie 133,
R. Scho e 139, J. Schuk a 35 , Y. Schu z139, K. Schwa z110, K. Schweda110, G. Scioli26 , E. Scompa in60 ,
J. E. Sege 15 , Y. Sekiguchi135, D. Sekiha a135, I. Selyuzhenko 95,110, S. Senyuko 139 , J. J. Seo62, D. Se eb yako 64,
L. Še kšny ˙e107, A. Se cenco68 , A. Shabano 64, A. Shabe ai118 , R. Shahoyan35, W. Shaikh113, A. Shanga ae 93,
A. Sha ma102, H. Sha ma121, M. Sha ma103, N. Sha ma102, S. Sha ma103, O. Sheibani128, A. I. Sheikh143, K. Shigaki47,
M. Shimomu a85, S. Shi inkin94, Q. Shou41, Y. Sibi iak90, S. Siddhan a56 , T. Siemia czuk87, T.F.D.Sil a
124,
D. Sil e my 82 , G. Sima o ic92, G. Simone i35, B. Singh107, R. Singh88, R. Singh103, R. Singh51, V. K. Singh143 ,
V. Singhal143, T. Sinha113, B. Si a 13, M. Si a32 , T. B. Skaali20, G. Sko odumo s106, M. Slupecki45 ,N.Smi no
148,
R. J. M. Snellings63 , C. Soncco115, J. Song128 , A. Songmoolnak119, F. So amel28 , S. So ensen133 , I. Spu owska121,
M. Spy opoulou-S assinaki86, J. S achel106 ,I.S an
68, P. J. S e anic133, S. F. S ie elmaie 106, D. S occo118 ,
M. M. S o e ed 37, C. P. S ylianidis92, A. A. P. Suaide124, T. Sugi a e47 , C. Sui e79 , M. Suljic35 , R. Sul ano 94,
M. Šumbe a97, V. Sumbe ia103, S. Sumowidagdo52 ,S.Swain
66, A. Szabo13, I. Sza ka13, U. Tabassam14, S. F. Tagha i107,
G. Taillepied137, J. Takahashi125 , G. J. Tamba e21 , S. Tang7,137, Z. Tang131 , M. Ta hini118, M. G. Ta zila49,
A. Tau o35, G. Tejeda Muñoz46 , A. Telesca35 , L. Te lizzi25, C. Te e oli128 , G. Te simono 3, S. Thaku 143,
D. Thomas122 , R. Tieulen 138 , A. Tikhono 64,A.R.Timmins
128, M. Tkacik120,A.Toia
69, N. Topilskaya64, M. Toppi53,
F. To ales-Acos a19,S.R.To es
38,A.T i i ó
33,57, S. T ipa hy70, T. T ipa hy50, S. T ogolo28 , G. T ombe a34, L. T opp39,
V. T ubniko 3, W. H. T zaska129, T. P. T zcinski144, B. A. T zeciak38 , A. Tumkin112, R. Tu isi58 , T.S.T e e
20,
K. Ullaland21 , E. N. Umaka128,A.U as
138 , M. U ioni142, G.L.Usai
23 ,M.Vala
39, N. Valle29, S. Valle o60 ,
N. an de Kolk63 ,L.V.R. anDo emalen
63, M. an Leeuwen92 , P. Vande Vy e35 ,D.Va ga
147 ,Z.Va ga
147 ,
M. Va ga-Ko a ago147 ,A.Va gas
46, M. Vasileiou86 , A. Vasilie 90, O. Vázquez Doce107, V. Veche nin116 ,
E. Ve cellin25 ,S.Ve ga aLimón
46, L. Ve mun 63,R.Vé esi
147 ,M.Ve weij
63,L.Vicko ic
36, Z. Vilakazi134,
O. Villalobos Baillie114,G.Vino
54, A. Vinog ado 90, T. Vi gili30 , V. Visla icius91, A. Vodopyano 76,B.Volkel
35,
M. A. Völkl105, K. Voloshin94, S. A. Voloshin145, G. Volpe34 , B. on Halle 35 , I. Vo obye 107 , D. Voscek120,
J. V láko á39, B. Wagne 21, M. Webe 117 , A. Weg zynek35 , S. C. Wenzel35, J. P. Wessels146 , J. Wiechula69,
J. Wikne20,G. Wilk87,J. Wilkinson110 ,G. A. Willems146,E. Willshe 114,B. Windelband106,M.Winn140 ,W. E. Wi 133,
J. R. W igh 122,Y.Wu
131,R.Xu
7, S. Yalcin78, Y. Yamaguchi47, K. Yamakawa47, S. Yang21, S. Yano47,140,Z.Yasin
108,
Z. Yin7, H. Yokoyama63,I.-K.Yoo
17,J.H.Yoon
62, S. Yuan21, A. Yuncu106, V. Yu chenko3, V. Zaccolo24 , A. Zaman14,
C. Zampolli35 , H. J. C. Zanoli63, N. Za dosh i35, A. Za ochen se 116 , P. Zá ada67, N. Za iyalo 112, H. Zb oszczyk144,
M. Zhalo 100, S. Zhang41, X. Zhang7, Y. Zhang131, V. Zhe ebche skii116,Y.Zhi
11, D. Zhou7, Y. Zhou91 ,J.Zhu
7,110,
Y. Zhu7, A. Zichichi26, G. Zino je 3,N.Zu lo
142
1A.I. Alikhanyan Na ional Science Labo a o y (Ye e an Physics Ins i u e) Founda ion, Ye e an, A menia
2AGH Uni e si y o Science and Technology, K aków, Poland
3Bogolyubo Ins i u e o Theo e ical Physics, Na ional Academy o Sciences o Uk aine, Kie , Uk aine
4Depa men o Physics and Cen e o As opa icle Physics and Space Science (CAPSS), Bose Ins i u e, Kolka a, India
5Budke Ins i u e o Nuclea Physics, No osibi sk, Russia
6Cali o nia Poly echnic S a e Uni e si y, San Luis Obispo, CA, USA
7Cen al China No mal Uni e si y, Wuhan, China
8Cen o de Aplicaciones Tecnológicas y Desa ollo Nuclea (CEADEN), Ha ana, Cuba
9Cen o de In es igación y de Es udios A anzados (CINVESTAV), Mexico Ci y and Mé ida, Mexico
10 Chicago S a e Uni e si y, Chicago, IL, USA
11 China Ins i u e o A omic Ene gy, Beijing, China
12 Chungbuk Na ional Uni e si y, Cheongju, Republic o Ko ea
13 Comenius Uni e si y B a isla a, Facul y o Ma hema ics, Physics and In o ma ics, B a isla a, Slo akia
14 COMSATS Uni e si y Islamabad, Islamabad, Pakis an
15 C eigh on Uni e si y, Omaha, NE, USA
16 Depa men o Physics, Aliga h Muslim Uni e si y, Aliga h, India
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17 Depa men o Physics, Pusan Na ional Uni e si y, Pusan, Republic o Ko ea
18 Depa men o Physics, Sejong Uni e si y, Seoul, Republic o Ko ea
19 Depa men o Physics, Uni e si y o Cali o nia, Be keley, CA, USA
20 Depa men o Physics, Uni e si y o Oslo, Oslo, No way
21 Depa men o Physics and Technology, Uni e si y o Be gen, Be gen, No way
22 Dipa imen o di Fisica dell’Uni e si à ’La Sapienza’ and Sezione INFN, Rome, I aly
23 Dipa imen o di Fisica dell’Uni e si à and Sezione INFN, Caglia i, I aly
24 Dipa imen o di Fisica dell’Uni e si à and Sezione INFN, T ies e, I aly
25 Dipa imen o di Fisica dell’Uni e si à and Sezione INFN, Tu in, I aly
26 Dipa imen o di Fisica e As onomia dell’Uni e si à and Sezione INFN, Bologna, I aly
27 Dipa imen o di Fisica e As onomia dell’Uni e si à and Sezione INFN, Ca ania, I aly
28 Dipa imen o di Fisica e As onomia dell’Uni e si à and Sezione INFN, Padua, I aly
29 Dipa imen o di Fisica e Nuclea e e Teo ica, Uni e si à di Pa ia and Sezione INFN, Pa ia, I aly
30 Dipa imen o di Fisica ‘E.R. Caianiello’ dell’Uni e si à and G uppo Collega o INFN, Sale no, I aly
31 Dipa imen o DISAT del Poli ecnico and Sezione INFN, Tu in, I aly
32 Dipa imen o di Scienze e Inno azione Tecnologica dell’Uni e si à del Piemon e O ien ale and INFN Sezione di To ino,
Alessand ia, I aly
33 Dipa imen o di Scienze MIFT, Uni e si à di Messina, Messina, I aly
34 Dipa imen o In e a eneo di Fisica ‘M. Me lin’ and Sezione INFN, Ba i, I aly
35 Eu opean O ganiza ion o Nuclea Resea ch (CERN), Gene a, Swi ze land
36 Facul y o Elec ical Enginee ing, Mechanical Enginee ing and Na al A chi ec u e, Uni e si y o Spli , Spli , C oa ia
37 Facul y o Enginee ing and Science, Wes e n No way Uni e si y o Applied Sciences, Be gen, No way
38 Facul y o Nuclea Sciences and Physical Enginee ing, Czech Technical Uni e si y in P ague, P ague, Czech Republic
39 Facul y o Science, P.J. Ša á ik Uni e si y, Košice, Slo akia
40 F ank u Ins i u e o Ad anced S udies, Johann Wol gang Goe he-Uni e si ä F ank u , F ank u , Ge many
41 Fudan Uni e si y, Shanghai, China
42 Gangneung-Wonju Na ional Uni e si y, Gangneung, Republic o Ko ea
43 Depa men o Physics, Gauha i Uni e si y, Guwaha i, India
44 Helmhol z-Ins i u ü S ahlen- und Ke nphysik, Rheinische F ied ich-Wilhelms-Uni e si ä Bonn, Bonn, Ge many
45 Helsinki Ins i u e o Physics (HIP), Helsinki, Finland
46 High Ene gy Physics G oup, Uni e sidad Au ónoma de Puebla, Puebla, Mexico
47 Hi oshima Uni e si y, Hi oshima, Japan
48 Hochschule Wo ms, Zen um ü Technologie ans e und Telekommunika ion (ZTT), Wo ms, Ge many
49 Ho ia Hulubei Na ional Ins i u e o Physics and Nuclea Enginee ing, Bucha es , Romania
50 Indian Ins i u e o Technology Bombay (IIT), Mumbai, India
51 Indian Ins i u e o Technology Indo e, Indo e, India
52 Indonesian Ins i u e o Sciences, Jaka a, Indonesia
53 INFN, Labo a o i Nazionali di F asca i, F asca i, I aly
54 INFN, Sezione di Ba i, Ba i, I aly
55 INFN, Sezione di Bologna, Bologna, I aly
56 INFN, Sezione di Caglia i, Caglia i, I aly
57 INFN, Sezione di Ca ania, Ca ania, I aly
58 INFN, Sezione di Pado a, Padua, I aly
59 INFN, Sezione di Roma, Rome, I aly
60 INFN, Sezione di To ino, Tu in, I aly
61 INFN, Sezione di T ies e, T ies e, I aly
62 Inha Uni e si y, Incheon, Republic o Ko ea
63 Ins i u e o G a i a ional and Suba omic Physics (GRASP), U ech Uni e si y/Nikhe , U ech , The Ne he lands
64 Ins i u e o Nuclea Resea ch, Academy o Sciences, Moscow, Russia
65 Ins i u e o Expe imen al Physics, Slo ak Academy o Sciences, Košice, Slo akia
66 Ins i u e o Physics, Homi Bhabha Na ional Ins i u e, Bhubaneswa , India
67 Ins i u e o Physics o he Czech Academy o Sciences, P ague, Czech Republic
68 Ins i u e o Space Science (ISS), Bucha es , Romania
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69 Ins i u ü Ke nphysik, Johann Wol gang Goe he-Uni e si ä F ank u , F ank u , Ge many
70 Ins i u o de Ciencias Nuclea es, Uni e sidad Nacional Au ónoma de México, Mexico Ci y, Mexico
71 Ins i u o de Física, Uni e sidade Fede al do Rio G ande do Sul (UFRGS), Po o Aleg e, B azil
72 Ins i u o de Física, Uni e sidad Nacional Au ónoma de México, Mexico Ci y, Mexico
73 iThemba LABS, Na ional Resea ch Founda ion, Some se Wes , Sou h A ica
74 Jeonbuk Na ional Uni e si y, Jeonju, Republic o Ko ea
75 Johann-Wol gang-Goe he Uni e si ä F ank u Ins i u ü In o ma ik, Fachbe eich In o ma ik und Ma hema ik,
F ank u , Ge many
76 Join Ins i u e o Nuclea Resea ch (JINR), Dubna, Russia
77 Ko ea Ins i u e o Science and Technology In o ma ion, Daejeon, Republic o Ko ea
78 KTO Ka a ay Uni e si y, Konya, Tu key
79 Labo a oi e de Physique des 2 In inis, I ène Jolio -Cu ie, O say, F ance
80 Labo a oi e de Physique Suba omique e de Cosmologie, Uni e si é G enoble-Alpes, CNRS-IN2P3, G enoble, F ance
81 Law ence Be keley Na ional Labo a o y, Be keley, CA, USA
82 Di ision o Pa icle Physics, Depa men o Physics, Lund Uni e si y, Lund, Sweden
83 Moscow Ins i u e o Physics and Technology, Moscow, Russia
84 Nagasaki Ins i u e o Applied Science, Nagasaki, Japan
85 Na a Women’s Uni e si y (NWU), Na a, Japan
86 Depa men o Physics, Na ional and Kapodis ian Uni e si y o A hens, School o Science, A hens, G eece
87 Na ional Cen e o Nuclea Resea ch, Wa saw, Poland
88 Na ional Ins i u e o Science Educa ion and Resea ch, Homi Bhabha Na ional Ins i u e, Ja ni, India
89 Na ional Nuclea Resea ch Cen e , Baku, Aze baijan
90 Na ional Resea ch Cen e Ku cha o Ins i u e, Moscow, Russia
91 Niels Boh Ins i u e, Uni e si y o Copenhagen, Copenhagen, Denma k
92 Nikhe , Na ional ins i u e o suba omic physics, Ams e dam, The Ne he lands
93 NRC Ku cha o Ins i u e IHEP, P o ino, Russia
94 NRC «Ku cha o »Ins i u e-ITEP, Moscow, Russia
95 NRNU Moscow Enginee ing Physics Ins i u e, Moscow, Russia
96 Nuclea Physics G oup, STFC Da esbu y Labo a o y, Da esbu y, UK
97 Nuclea Physics Ins i u e o he Czech Academy o Sciences, ˇ
Rež u P ahy, Czech Republic
98 Oak Ridge Na ional Labo a o y, Oak Ridge, TN, USA
99 Ohio S a e Uni e si y, Columbus, OH, USA
100 Pe e sbu g Nuclea Physics Ins i u e, Ga china, Russia
101 Physics Depa men , Facul y o science, Uni e si y o Zag eb, Zag eb, C oa ia
102 Physics Depa men , Panjab Uni e si y, Chandiga h, India
103 Physics Depa men , Uni e si y o Jammu, Jammu, India
104 Physics Depa men , Uni e si y o Rajas han, Jaipu , India
105 Physikalisches Ins i u , Ebe ha d-Ka ls-Uni e si ä Tübingen, Tübingen, Ge many
106 Physikalisches Ins i u , Rup ech -Ka ls-Uni e si ä Heidelbe g, Heidelbe g, Ge many
107 Physik Depa men , Technische Uni e si ä München, Munich, Ge many
108 PINSTECH, Islamabad, Pakis an
109 Poli ecnico di Ba i and Sezione INFN, Ba i, I aly
110 Resea ch Di ision and Ex eMe Ma e Ins i u e EMMI, GSI Helmhol zzen um ü Schwe ionen o schung GmbH,
Da ms ad , Ge many
111 Rudje Boško i´c Ins i u e, Zag eb, C oa ia
112 Russian Fede al Nuclea Cen e (VNIIEF), Sa o , Russia
113 Saha Ins i u e o Nuclea Physics, Homi Bhabha Na ional Ins i u e, Kolka a, India
114 School o Physics and As onomy, Uni e si y o Bi mingham, Bi mingham, UK
115 Sección Física, Depa amen o de Ciencias, Pon i icia Uni e sidad Ca ólica del Pe ú, Lima, Pe u
116 S . Pe e sbu g S a e Uni e si y, S . Pe e sbu g, Russia
117 S e an Meye Ins i u ü Suba oma e Physik (SMI), Vienna, Aus ia
118 SUBATECH, IMT A lan ique, Uni e si é de Nan es, CNRS-IN2P3, Nan es, F ance
119 Su ana ee Uni e si y o Technology, Nakhon Ra chasima, Thailand
123
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120 Technical Uni e si y o Košice, Košice, Slo akia
121 The Hen yk Niewodniczanski Ins i u e o Nuclea Physics, Polish Academy o Sciences, K aków, Poland
122 The Uni e si y o Texas a Aus in, Aus in, TX, USA
123 Uni e sidad Au ónoma de Sinaloa, Culiacán, Mexico
124 Uni e sidade de São Paulo (USP), São Paulo, B azil
125 Uni e sidade Es adual de Campinas (UNICAMP), Campinas, B azil
126 Uni e sidade Fede al do ABC, San o And e, B azil
127 Uni e si y o Cape Town, Cape Town, Sou h A ica
128 Uni e si y o Hous on, Hous on, TX, USA
129 Uni e si y o Jy äskylä, Jy äskylä, Finland
130 Uni e si y o Li e pool, Li e pool, UK
131 Uni e si y o Science and Technology o China, He ei, China
132 Uni e si y o Sou h-Eas e n No way, Tonsbe g, No way
133 Uni e si y o Tennessee, Knox ille, TN, USA
134 Uni e si y o he Wi wa e s and, Johannesbu g, Sou h A ica
135 Uni e si y o Tokyo, Tokyo, Japan
136 Uni e si y o Tsukuba, Tsukuba, Japan
137 Uni e si é Cle mon Au e gne, CNRS/IN2P3, LPC, Cle mon -Fe and, F ance
138 Ins i u de Physique des 2 In inis de Lyon, Uni e si é de Lyon, CNRS/IN2P3, Lyon, F ance
139 Uni e si é de S asbou g, CNRS, IPHC UMR 7178, 67000 S asbou g, F ance
140 Dépa men de Physique Nucléai e (DPhN), Uni e si é Pa is-Saclay Cen e d’E udes de Saclay (CEA), IRFU, Saclay,
F ance
141 Uni e si à degli S udi di Foggia, Foggia, I aly
142 Uni e si à di B escia and Sezione INFN, B escia, I aly
143 Va iable Ene gy Cyclo on Cen e, Homi Bhabha Na ional Ins i u e, Kolka a, India
144 Wa saw Uni e si y o Technology, Wa saw, Poland
145 Wayne S a e Uni e si y, De oi , MI, USA
146 Ins i u ü Ke nphysik, Wes älische Wilhelms-Uni e si ä Müns e , Müns e , Ge many
147 Wigne Resea ch Cen e o Physics, Budapes , Hunga y
148 Yale Uni e si y, New Ha en, CT, USA
149 Yonsei Uni e si y, Seoul, Republic o Ko ea
aAlso a : I alian Na ional Agency o New Technologies, Ene gy and Sus ainable Economic De elopmen (ENEA),
Bologna, I aly
bAlso a : Dipa imen o DET del Poli ecnico di To ino, Tu in, I aly
cAlso a : M.V. Lomonoso Moscow S a e Uni e si y, D.V. Skobel syn Ins i u e o Nuclea Physics, Moscow, Russia
dAlso a : Ins i u e o Theo e ical Physics, Uni e si y o W oclaw, W oclaw, Poland
eDeceased
123