Measurement of charm and beauty production at central rapidity versus charged-particle multiplicity in proton-proton collisions at √s = 7 TeV
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Measu emen o cha m and beau y p oduc ion a cen al apidi y e sus cha ged-
pa icle mul iplici y in p o on-p o on collisions a √s = 7 TeV
ALICE Collabo a ion
ALICE Collabo a ion. (2015). Measu emen o cha m and beau y p oduc ion a
cen al apidi y e sus cha ged-pa icle mul iplici y in p o on-p o on collisions a √s =
7 TeV. Jou nal o High Ene gy Physics, 2015(9), A icle 148.
h ps://doi.o g/10.1007/JHEP09(2015)148
2015
JHEP09(2015)148
Published o SISSA by Sp inge
Recei ed:May 11, 2015
Re ised:June 5, 2015
Accep ed:Augus 10, 2015
Published:Sep embe 22, 2015
Measu emen o cha m and beau y p oduc ion a
cen al apidi y e sus cha ged-pa icle mul iplici y in
p o on-p o on collisions a √s=7 TeV
The ALICE collabo a ion
E-mail: [email p o ec ed]
Abs ac : P omp D meson and non-p omp J/ψ yields a e s udied as a unc ion o he
mul iplici y o cha ged pa icles p oduced in inelas ic p o on-p o on collisions a a cen e-
o -mass ene gy o √s= 7 TeV. The esul s a e epo ed as a a io be ween yields in a
gi en mul iplici y in e al no malised o he mul iplici y-in eg a ed ones ( ela i e yields).
They a e shown as a unc ion o he mul iplici y o cha ged pa icles no malised o he
a e age alue o inelas ic collisions ( ela i e cha ged-pa icle mul iplici y). D0, D+and
D∗+mesons a e measu ed in i e pTin e als om 1 GeV/c o 20 GeV/c and o |y|<0.5
ia hei had onic decays. The D-meson ela i e yield is ound o inc ease wi h inc easing
cha ged-pa icle mul iplici y. Fo e en s wi h mul iplici y six imes highe han he a e age
mul iplici y o inelas ic collisions, a yield enhancemen o a ac o abou 15 ela i e o he
mul iplici y-in eg a ed yield in inelas ic collisions is obse ed. The yield enhancemen is
independen o ans e se momen um wi hin he unce ain ies o he measu emen . The
D0-meson ela i e yield is also measu ed as a unc ion o he ela i e mul iplici y a o wa d
pseudo- apidi y. The non-p omp J/ψ, i.e. he B had on, con ibu ion o he inclusi e J/ψ
p oduc ion is measu ed in he di-elec on decay channel a cen al apidi y. I is e alua ed
o pT>1.3 GeV/c and |y|<0.9, and ex apola ed o pT>0. The ac ion o non-p omp
J/ψ in he inclusi e J/ψ yields shows no dependence on he cha ged-pa icle mul iplici y a
cen al apidi y. Cha m and beau y had on ela i e yields exhibi a simila inc ease wi h
inc easing cha ged-pa icle mul iplici y. The measu emen s a e compa ed o PYTHIA 8,
EPOS 3 and pe cola ion calcula ions.
Keywo ds: Had on-Had on Sca e ing
A Xi eP in : 1505.00664
Open Access, Copy igh CERN,
o he bene i o he ALICE Collabo a ion.
A icle unded by SCOAP3.
doi:10.1007/JHEP09(2015)148
JHEP09(2015)148
Con en s
1 In oduc ion 1
2 Expe imen al appa a us and da a sample 4
3 Mul iplici y de ini ion and co ec ions 6
4 D-meson analysis 7
4.1 D-meson econs uc ion 7
4.2 Co ec ions 9
4.3 Sys ema ic unce ain ies 11
4.4 Resul s 12
4.4.1 S udies wi h he cha ged-pa icle mul iplici y a o wa d apidi y 13
5 Non-p omp J/ψ analysis 16
5.1 Non-p omp J/ψ econs uc ion 16
5.2 Co ec ions 18
5.3 Sys ema ic unce ain ies 19
5.4 Resul s 21
6 Compa ison o cha m and beau y p oduc ion 21
7 Compa ison o heo e ical calcula ions 24
7.1 PYTHIA 8 simula ions 24
7.2 Compa ison o da a wi h models 26
8 Summa y 29
A Tables o he esul s 31
The ALICE collabo a ion 39
1 In oduc ion
The s udy o he p oduc ion o had ons con aining hea y qua ks, i.e. cha m and beau y,
in p o on-p o on (pp) collisions a he La ge Had on Collide (LHC) p o ides a way o
es calcula ions based on pe u ba i e Quan um Ch omodynamics (pQCD) a he high-
es a ailable collision ene gies. The inclusi e p oduc ion c oss sec ions o cha m mesons
measu ed in pp collisions a he LHC a bo h cen al [1,2] and o wa d [3] apidi y a e
desc ibed by heo e ical p edic ions based on pQCD calcula ions wi h he collinea ac o i-
sa ion app oach a nex - o-leading o de (e.g. in he gene al-mass a iable- la ou -numbe
– 1 –
JHEP09(2015)148
scheme, GM-VFNS [4]) o a ixed o de wi h nex - o-leading-log esumma ion (FONLL [5–
8]) wi hin heo e ical unce ain ies. The compa isons sugges ha cha m p oduc ion is
unde (o e ) es ima ed by he cen al alues o he FONLL (GM-VFNS) calcula ions.
The measu ed D-meson p oduc ion c oss sec ions in pp collisions a he LHC can also
be desc ibed by pQCD calcula ions pe o med in he amewo k o kT- ac o isa ion in he
leading o de (LO) app oxima ion [9]. Beau y p oduc ion c oss sec ion measu emen s in
pp collisions a √s= 7 TeV [10–14] a e well desc ibed by implemen a ions o FONLL and
GM-VFNS [7,15]. In he case o B mesons, he measu ed c oss sec ions a e close o he
cen al alue o he FONLL and GM-VFNS p edic ions. A simila si ua ion was obse ed
in pp collisions a √s= 1.96 TeV a he FNAL Te a on collide [16–18].
The measu emen o hea y- la ou p oduc ion in pp collisions as a unc ion o he
cha ged-pa icle mul iplici y p oduced in he collision could p o ide insigh in o he p o-
cesses occu ing in he collision a he pa onic le el and he in e play be ween he ha d
and so mechanisms in pa icle p oduc ion. These aspec s a e expec ed o depend on
he ene gy and on he impac pa ame e ( he dis ance be ween he colliding p o ons in
he plane pe pendicula o he beam di ec ion) o he pp collision [19–21]. In he im-
pac pa ame e ep esen a ion o p o on-p o on collisions, he o e lap o he nucleon wa e
unc ions in p o on-p o on collisions can be desc ibed by a geome ical pic u e wi h wo
sepa a e ans e se dis ance scales: he impac pa ame e o he collision and he ans e se
spa ial pa onic dis ibu ion [20,22–24]. In pa icula , pp collisions wi h a ha d pa on-
pa on sca e ing a e p edic ed o be mo e cen al (i.e. ha e smalle impac pa ame e )
han minimum-bias e en s [20,25].
The NA27 Collabo a ion obse ed in 1988 ha he a e age cha ged-pa icle mul iplic-
i y in e en s wi h open cha m p oduc ion was highe by abou 20% han in e en s wi hou
cha m p oduc ion [26]. A so ening o he momen um spec a o had ons p oduced in as-
socia ion wi h cha m was also obse ed. This esul was in e p e ed as a consequence o
he mo e cen al na u e o collisions leading o cha m p oduc ion.
A LHC ene gies, wo addi ional con ibu ions o cha m p oduc ion and i s ela ion
o mul iplici y ha e o be conside ed. The i s e ec is he likely la ge amoun o gluon
adia ion associa ed o he sho dis ance p oduc ion p ocesses a la ge ene gies and pa -
icle ans e se momen a. The second is he con ibu ion o Mul iple-Pa on In e ac ions
(MPI) [27–29], i.e. se e al ha d pa onic in e ac ions occu ing in a single pp collision. In
his con ex , pQCD-inspi ed models desc ibe he inal-s a e pa icles p oduced in had onic
collisions wi h a wo-componen app oach, namely an ini ial ha d pa onic sca e ing p o-
cess, ha gi es ise o collima ed clus e s o had ons (je s), and an unde lying e en ,
consis ing o he inal-s a e pa icles ha a e no associa ed wi h he ini ial ha d sca -
e ing. While he ha d sca e ing p ocess can be compu ed wi h a pQCD app oach, he
desc ip ion o he unde lying e en , which is hough o be domina ed by pa icles p oduced
in so p ocesses and by pe u ba i e (mini)je s wi h ela i ely small ans e se momen a
(so MPIs), is based on a phenomenological model. In pa icula , pQCD-based models o
MPIs p o ide a consis en way o desc ibe high mul iplici y pp collisions, and ha e been
implemen ed in ecen Mon e Ca lo gene a o s like PYTHIA 6 [30], PYTHIA 8 [31], and
HERWIG [32]. Measu emen s by he CMS Collabo a ion o je and unde lying e en p op-
– 2 –
JHEP09(2015)148
e ies as a unc ion o mul iplici y in pp collisions a √s= 7 TeV can be be e desc ibed
by e en gene a o s including MPI [33,34]. The analysis o minije p oduc ion pe o med
by he ALICE Collabo a ion [35] indica es ha high mul iplici ies in pp collisions a e
eached h ough a high numbe o MPIs and a highe han a e age numbe o agmen s
pe pa on. Upwa d luc ua ions o he gluon densi y in he colliding p o ons a e also ad-
oca ed o desc ibe he esul s om high mul iplici y pp collisions a he LHC [21,36,37].
Indeed, he ans e se s uc u e o he p o on, as p obed in ha d pa onic sca e ing p o-
cesses, is p edic ed o play a c ucial ole in de ining he unde lying e en s uc u e and he
p obabili y o MPIs [25]. In he hea y- la ou sec o , he LHCb Collabo a ion epo ed
measu emen s o double cha m p oduc ion in pp collisions a he LHC (D0+X, J/ψ +X
and J/ψ + J/ψ whe e X= D0,D+,D+
s,Λ+
c), which sugges ha MPIs also play a ole a
he ha d momen um scale ele an o cc p oduc ion [38,39].
The ALICE Collabo a ion published he i s measu emen o inclusi e J/ψ p oduc ion
as a unc ion o cha ged-pa icle mul iplici y, exp essed as he pseudo- apidi y densi y
o cha ged pa icles dNch/dηa mid- apidi y, in pp collisions a √s= 7 TeV [40]. An
app oxima ely linea inc ease o he yield o J/ψ wi h he cha ged-pa icle mul iplici y was
obse ed in a mul iplici y ange eaching ou imes he a e age mul iplici y hdNch/dηi.
The measu emen s a |y|<0.9 and 2.5< y < 4.0 we e compa ible wi hin he unce ain ies.
Bo h he la ge amoun o gluon adia ion and he con ibu ion o MPI in collisions whe e
hea y qua ks a e p oduced can induce a co ela ion be ween he yield o qua konia and
he cha ged-pa icle mul iplici y p oduced in he collision. The measu ed ise o J/ψ yield
wi h inc easing mul iplici y can also be desc ibed in he amewo k o s ing in e ac ion o
pa on sa u a ion models. In pa icula , in e . [41] a s onge - han-linea end in he high
densi y domain is an icipa ed as a consequence o he in e ac ion (o e lap) o s ings, which
educes he e ec i e numbe o sou ces o so -pa icle p oduc ion. The inc easing end
o J/ψ yield wi h mul iplici y is also desc ibed in a amewo k in which high mul iplici ies
a e a ained in pp collisions due o he con ibu ion o highe Fock s a es in he p o on,
leading o a la ge numbe o gluons pa icipa ing in he collision [37].
I is also wo h poin ing ou ha he cha ged-pa icle densi ies a ained in high-
mul iplici y pp collisions a he LHC a e o he same o de o magni ude as hose measu ed
in semi-pe iphe al hea y-ion collisions a lowe cen e-o -mass ene gies [42]. In hose hea y-
ion collisions, he measu ed momen um dis ibu ions o ligh had ons indica e ha he sys-
em unde goes a collec i e expansion, which can be desc ibed in e ms o hyd odynamics.
Recen measu emen s in high-mul iplici y p–Pb collisions a √sNN = 5.02 TeV [43–48] and
in high-mul iplici y pp collisions a he LHC [49] indica e ha such a collec i e beha iou
could also be a play in hese sys ems. I cha m qua ks we e o ollow a collec i e mo ion in
high-mul iplici y e en s, hei momen um spec a would be al e ed, and he hea y- la ou
had on ela i e yields a high mul iplici y would a y as a unc ion o pT[50].
The measu emen s o he pT-di e en ial p omp D meson and non-p omp J/ψ c oss
sec ions in pp collisions a √s= 7 TeV wi h he ALICE expe imen a he LHC we e
published in e e ences [1,10]. In his pape , we epo he measu emen o he ela i e
open hea y- la ou p oduc ion yields as a unc ion o he cha ged-pa icle mul iplici y in
pp collisions a √s= 7 TeV. Open cha m and beau y p oduc ion is measu ed by econ-
– 3 –
JHEP09(2015)148
s uc ing p omp D mesons and non-p omp J/ψ, i.e. J/ψ mesons coming om he decay
o beau y had ons. The expe imen al se up and he mul iplici y es ima ion a e desc ibed
in sec ions 2and 3, espec i ely. P omp D0, D+, D∗+mesons we e measu ed a cen al
apidi y, |y|<0.5, in six mul iplici y in e als and i e pTin e als om 1 GeV/c o 20
GeV/c (sec ion 4). The non-p omp ac ion o J/ψ p oduc ion was measu ed in he apid-
i y in e al |y|<0.9 in i e mul iplici y in e als and o pT>1.3 GeV/c and ex apola ed
o pT>0 (sec ion 5). The ela i e yields as a unc ion o cha ged-pa icle mul iplici y a e
compa ed in sec ion 6. Finally, model calcula ions a e discussed and compa ed wi h da a
in sec ion 7.
2 Expe imen al appa a us and da a sample
The ALICE appa a us [51] consis s o a cen al ba el de ec o co e ing he pseudo- apidi y
in e al |η|<0.9, a o wa d muon spec ome e co e ing he pseudo- apidi y in e al
−4.0< η < −2.5, and a se o de ec o s a o wa d and backwa d apidi ies used o
igge ing and e en cha ac e iza ion. In he ollowing, he subsys ems ha a e ele an
o he D meson and non-p omp J/ψ analyses a e desc ibed.
The cen al ba el de ec o s a e loca ed inside a la ge solenoidal magne , which p o ides
a magne ic ield o 0.5 T along he beam di ec ion (zaxis in he ALICE e e ence ame).
T acking and pa icle iden i ica ion a e pe o med using he in o ma ion p o ided by he
Inne T acking Sys em (ITS), he Time P ojec ion Chambe (TPC) and he Time O
Fligh (TOF) de ec o s, ha ha e ull azimu hal co e age in he pseudo- apidi y in e al
|η|<0.9. The de ec o closes o he beam axis is he ITS, which is composed o six
cylind ical laye s o silicon de ec o s, wi h adial dis ances om he beam axis anging
om 3.9 cm o 43.0 cm. The wo inne mos laye s, wi h a e age adii o 3.9 cm and
7.6 cm, a e equipped wi h Silicon Pixel De ec o s (SPD). The wo SPD laye s, co e ing
he pseudo- apidi y anges o |η|<2.0 and |η|<1.4 espec i ely, ha e 1200 SPD eadou
chips. The wo in e media e laye s a e made o Silicon D i De ec o s (SDD), while Silicon
S ip De ec o s (SSD) equip he wo ou e mos laye s. The high spa ial esolu ion o he
silicon senso s, oge he wi h he low ma e ial budge (on a e age 7.7% o a adia ion
leng h o acks c ossing he ITS pe pendicula ly o he de ec o su aces, i.e. η= 0)
and he small dis ance o he inne mos laye om he beam acuum ube, allow o he
measu emen o he ack impac pa ame e in he ans e se plane (d0), i.e. he dis ance
o closes app oach o he ack o he p ima y e ex in he plane ans e se o he beam
di ec ion, wi h a esolu ion be e han 75 µm o ans e se momen a pT>1 GeV/c [52].
The SPD p o ides also a measu emen o he mul iplici y o cha ged pa icles p oduced in
he collision based on ack segmen s ( ackle s) buil by associa ing pai s o hi s in he
wo SPD laye s.
A la ge adii (85 < < 247 cm), a 510 cm long cylind ical TPC [53] p o ides
ack econs uc ion wi h up o 159 h ee-dimensional space poin s pe ack, as well as
pa icle iden i ica ion ia he measu emen o he speci ic ene gy deposi dE/dxin he
gas. The cha ged pa icle iden i ica ion capabili y o he TPC is supplemen ed by he
TOF [54], which is equipped wi h Mul i-gap Resis i e Pla e Chambe s (MRPCs) loca ed
– 4 –
JHEP09(2015)148
a adial dis ances be ween 377 and 399 cm om he beam axis. The o e all TOF esolu ion
including he unce ain y on he ime a which he collision ook place, and he acking
and momen um esolu ion was abou 160 ps o he da a- aking pe iod conside ed in hese
analyses.
The V0 de ec o [55], used o igge ing and o es ima ing he mul iplici y o cha ged
pa icles in he o wa d apidi y egion, consis s o wo a ays o 32 scin illa o s each, placed
a ound he beam acuum ube on ei he side o he in e ac ion egion a z=−90 cm and
z= +340 cm. The wo a ays co e he pseudo- apidi y in e als −3.7< η < −1.7 and
2.8< η < 5.1, espec i ely.
The da a om p o on-p o on (pp) collisions a a cen e-o -mass ene gy o √s= 7 TeV
used o he analyses we e eco ded in 2010. The da a sample consis s o abou 314 million
minimum-bias (MB) e en s, co esponding o an in eg a ed luminosi y o Lin ≃5 nb−1.
Minimum-bias collisions we e igge ed by equi ing a leas one hi in ei he o he V0
coun e s o in he SPD (|η|<2), in coincidence wi h he a i al ime o p o on bunches
om bo h di ec ions. This igge was es ima ed o be sensi i e o abou 85% o he
inelas ic c oss sec ion [56].
To en ich he da a sample wi h high mul iplici y e en s, a High Mul iplici y (HM)
igge based on he mul iplici y in o ma ion p o ided by he ou e SPD laye was also
used. Each eadou chip o he SPD p omp ly asse s a digi al pulse, called Fas OR bi , on
he p esence o a leas one i ing pixel. A sample o abou 6 million e en s was collec ed
applying a selec ion on he minimum numbe o eadou chips ha ing asse ed his digi al
pulse. The h eshold was con igu ed o selec he ≈0.7% o he e en s wi h highes
numbe o hi s in he ou e SPD laye . This HM- igge sample (Lin ≃14 nb−1) p o ides
an inc ease o s a is ics by a ac o o abou 2.8 ela i e o he MB igge o e en s wi h
mo e han 50 ackle s, co esponding o abou six imes he a e age mul iplici y.
Only e en s wi h in e ac ion e ex econs uc ed om acks wi h a coo dina e |z|<
10 cm along he beam line we e used o he analysis. In he conside ed da a samples,
he ins an aneous luminosi y was limi ed o 0.6–1.2×1029 cm−2s−1by displacing he
beams in he ans e se plane by 3.8 imes he RMS o hei ans e se p o ile. In his
way, he in e ac ion p obabili y pe bunch c ossing was kep in he ange 0.04–0.08, wi h
a p obabili y o collision pile-up below 4% pe igge ed e en . An algo i hm o de ec
mul iple in e ac ion e ices based on SPD ack segmen s, o ackle s, was used o u he
educe he pile-up con ibu ion. An e en is ejec ed om he analysed da a sample i a
second in e ac ion e ex is ound, which has a leas h ee associa ed ackle s, and is
sepa a ed om he i s one by mo e han 0.8 cm along z. This emo es abou 48% o he
pile-up e en s. The emaining pile-up con amina ion has wo con ibu ions: e en s wi h
pile-up o collisions wi h ∆z < 0.8 cm and e en s in which he piled-up collisions ha e
low-mul iplici y (less han h ee cha ged pa icles econs uc ed in he SPD). In he case
o pile-up o collisions wi h small sepa a ion along z, he mul iplici y es ima ion may be
biased because some o he ackle s o cha ged pa icles om di e en in e ac ions may
be added oge he . Acco ding o simula ions, he numbe o ackle s esul s o be biased
when he piled-up e ices a e sepa a ed along zby less han 0.6 cm. Combining his
esul wi h he shape o he luminous egion along he beam di ec ion and he maximum
– 5 –
JHEP09(2015)148
pile-up a e o 4%, he o e all p obabili y ha wo piled-up e en s induce a bias in he
de e mina ion o mul iplici y was ound o be lowe han 0.3%. The ac ion o e en s wi h
biased numbe o ackle s inc eases wi h inc easing mul iplici y and i was es ima ed o
be below 2% a he highes mul iplici ies conside ed in his analysis, while he esul ing
bias on he measu ed numbe o ackle s was ound o be negligible in all he mul iplici y
classes.
3 Mul iplici y de ini ion and co ec ions
In he p esen analysis, he expe imen al es ima o o he cha ged-pa icle mul iplici y is he
numbe o ackle s in he in e al |η|<1.0 (N ackle s). T ackle s a e ack segmen s de ined
by combining he clus e s in he SPD de ec o wi h he econs uc ed p ima y e ex
posi ion. T ackle s a e equi ed o poin o he p ima y in e ac ion e ex wi hin ±1 cm in
he ans e se plane and ±3 cm in he zdi ec ion [51,52]. This mul iplici y es ima o is he
same as was used in p e ious s udies pe o med o inclusi e J/ψ p oduc ion [40]. Mon e
Ca lo simula ions o he de ec o esponse ha e shown ha N ackle s is p opo ional o he
pseudo- apidi y densi y o he gene a ed cha ged p ima y pa icles, dNch/dη, wi hin 2%.
P ima y pa icles a e de ined as p omp pa icles p oduced in he collision and all decay
p oduc s, excep p oduc s om weak decays o s ange pa icles. The pseudo- apidi y
co e age o he SPD de ec o changes wi h he posi ion o he in e ac ion e ex along he
beam line, z x, and wi h ime due o he a ia ion o he numbe o inac i e channels. The
de ec o esponse o e he analysed da a aking pe iod is equalised by means o a da a-
based co ec ion, which is applied on an e en -by-e en basis depending on z x and ime.
The measu emen s in he N ackle s ∈[1,49] in e al a e pe o med using minimum-
bias igge ed da a, while hose in he [50,80] ange exploi he SPD-based HM igge
desc ibed abo e. The HM igge is ully e icien o e en s wi h N ackle s >65. The
numbe o e en s and he D-meson candida e in a ian mass dis ibu ions we e co ec ed
o he HM igge ine iciency in he N ackle s ∈[50,65] ange by means o a da a-d i en
e-weigh ing p ocedu e. The N ackle s-dependen e en weigh s we e de ined om he a io
o he measu ed dis ibu ions o he numbe o ackle s in he HM and minimum-bias
igge samples. The e ec o his co ec ion on he pe -e en aw yield was o abou 2.5%.
The a e age dNch/dηo e en s in he highes N ackle s in e al was de e mined om he
minimum-bias sample.
The analysis esul s a e p esen ed as a unc ion o he ela i e cha ged-pa icle mul i-
plici y a cen al apidi y, (dNch/dη)jhdNch/dηi, whe e hdNch/dηi=6.01±0.01(s a .)+0.20
−0.12
(sys .) is measu ed in inelas ic pp collisions a √s= 7 TeV wi h a leas one cha ged pa -
icle in |η|<1.0 [57]. The ela i e quan i ies a e used o minimise he expe imen al
unce ain ies and o acili a e he compa ison wi h o he measu emen s and models. The
conside ed N ackle s in e als and he co esponding ela i e cha ged-pa icle mul iplici y
anges a e summa ised in able 1. The highes N ackle s in e al conside ed in he analysis
ex ends o a mul iplici y o abou 9 imes he hdNch/dηio inelas ic pp collisions and he
a e age mul iplici y o e en s in his N ackle s in e al is abou six imes he hdNch/dηi.
The unce ain y on (dNch/dη)jhdNch/dηiis 6%; i includes he in luence o (i) he de e -
– 6 –
JHEP09(2015)148
N ackle s (dNch/dη)j(dNch/dη)jhdNch/dηiND0
e en s/106NJ/ψ
e en s/106
[1,8] 2.7 0.45+0.03
−0.03 155.1 —
[4,8] 3.8 0.63+0.04
−0.04 — 89.0
[9,13] 7.1 1.18+0.07
−0.07 46.2 50.5
[14,19] 10.7 1.78+0.10
−0.11 32.0 35.5
[20,30] 15.8 2.63+0.15
−0.17 24.7 28.0
[31,49] 24.1 4.01+0.23
−0.25 7.9 9.5
[50,80] 36.7 6.11+0.35
−0.39 1.7 —
Table 1. Summa y o he mul iplici y in e als used o he analyses. The numbe o econs uc ed
ackle s N ackle s, he a e age cha ged-pa icle mul iplici y (dNch/dη)j, and he ela i e cha ged-
pa icle mul iplici y (dNch/dη)jhdNch/dηia e de ailed. The numbe o e en s analysed in he
a ious mul iplici y anges o bo h he D-meson and J/ψ analyses a e epo ed. The numbe o
e en s o he N ackle s in e al [50,80] a e co ec ed o he high mul iplici y igge e iciency, as
explained in sec ion 3.
mina ion o he N ackle s o dNch/dηp opo ionali y ac o , 2%, (ii) i s possible de ia ion
om linea i y, 5%, (iii) and he unce ain y on he measu ed hdNch/dηi.
The analysis o D0p oduc ion is also ca ied ou as a unc ion o he cha ged-pa icle
mul iplici y in he egions −3.7< η < −1.7 and 2.8< η < 5.1, as measu ed wi h he cha ge
collec ed by he V0 scin illa o coun e s, NV0, epo ed in uni s o he minimum-ionizing-
pa icle cha ge. The mo i a ion o s udying he mul iplici y dependence o cha med-meson
p oduc ion also wi h his es ima o is ha he e en mul iplici y and he D-meson yields
a e e alua ed in di e en pseudo apidi y anges, educing he e ec s o au o-co ela ions.
In con as , wi h he N ackle s es ima o also he D-meson decay p oduc s and he cha ged
pa icles p oduced in he agmen a ion o he same cha m qua k a e included in he
mul iplici y e alua ion. Mon e Ca lo simula ions demons a e ha NV0 is p opo ional o
he cha ged-pa icle mul iplici y in ha pseudo- apidi y in e al. In his pape we epo
D0 ela i e yields as a unc ion o he ela i e unco ec ed mul iplici y in he V0 de ec o ,
NV0hNV0i(see sec ion 4.4.1).
4 D-meson analysis
4.1 D-meson econs uc ion
Cha m p oduc ion was s udied by econs uc ing D0, D+and D∗+mesons, and hei an-
ipa icles, ia hei had onic decay channels D0→K−π+(wi h b anching a io, BR, o
3.88±0.05%), D+→K−π+π+(BR o 9.13±0.19%), and D∗+→D0π+(BR o 67.7±0.05%)
wi h D0→K−π+[58]. D-meson candida es we e selec ed wi h he same s a egy as de-
sc ibed in [1]. The selec ion o D0and D+decays (weak decays wi h mean p ope decay
– 7 –
JHEP09(2015)148
〉
T
pdy/dN
2
d〈) /
T
pdy/dN
2
(d
5
10
15
20
25
c<8 GeV/
T
p meson, 4<
0
D
c<8 GeV/
T
p meson, 4<
+
D
c<8 GeV/
T
p meson, 4<
+
D*
ALICE
|<0.5y = 7 TeV, |s
pp
no shown〉η/dNd〈) / η/dN 6% unc. on (d±
+6%/-3% no maliza ion unc. no shown
〉η/d
ch
Nd〈) / η/d
ch
N (d
0 1 2 3 4 5 6 7 8 9
B eed-down unc.
0.4−
0.2−
0
0.2
0.4 1/2 (2) a low (high) mul iplici y×B ac ion hypo hesis:
(a) D meson wi h 4 < pT<8 GeV/c.
〉
T
pdy/dN
2
d〈) /
T
pdy/dN
2
(d
5
10
15
20
25
c<12 GeV/
T
p meson, 8<
0
D
c<12 GeV/
T
p meson, 8<
+
D
c<12 GeV/
T
p meson, 8<
+
D*
ALICE
|<0.5y = 7 TeV, |s
pp
no shown〉η/dNd〈) / η/dN 6% unc. on (d±
+6%/-3% no maliza ion unc. no shown
〉η/d
ch
Nd〈) / η/d
ch
N (d
0 1 2 3 4 5 6 7 8 9
B eed-down unc.
0.4−
0.2−
0
0.2
0.4 1/2 (2) a low (high) mul iplici y×B ac ion hypo hesis:
(b) D meson wi h 8 < pT<12 GeV/c.
〉
T
pdy/dN
2
d〈) /
T
pdy/dN
2
(d
5
10
15
20
25
c<20 GeV/
T
p meson, 12<
+
D*
ALICE
|<0.5y = 7 TeV, |s
pp
no shown〉η/dNd〈) / η/dN 6% unc. on (d±
+6%/-3% no maliza ion unc. no shown
〉η/d
ch
Nd〈) / η/d
ch
N (d
0 1 2 3 4 5 6 7 8 9
B eed-down unc.
0.4−
0.2−
0
0.2
0.4 1/2 (2) a low (high) mul iplici y×B ac ion hypo hesis:
(c) D meson wi h 12 < pT<20 GeV/c.
Figu e 3. D0, D+and D∗+meson ela i e yields o each pTin e al as a unc ion o cha ged-
pa icle mul iplici y a cen al apidi y. The ela i e yields a e p esen ed on he op panels wi h hei
s a is ical ( e ical ba s) and sys ema ic (boxes) unce ain ies, excep o he eed-down ac ion
unce ain y ha is d awn sepa a ely in he bo om panels. D0mesons a e ep esen ed by ed ci cles,
D+by g een squa es, and D∗+by blue iangles. The posi ion o he poin s on he abscissa is he
a e age alue o (dNch/dη)hdNch/dηi. Fo D+and D∗+mesons he poin s a e shi ed ho izon ally
by 1.5% o imp o e he isibili y. The diagonal (dashed) line is also shown o guide he eye.
– 14 –
JHEP09(2015)148
〉
T
pdy/dN
2
d〈) /
T
pdy/dN
2
(d
5
10
15
20
25
c < 2 GeV/
T
p 1 <
c < 4 GeV/
T
p 2 <
c < 8 GeV/
T
p 4 <
c < 12 GeV/
T
p 8 <
c < 20 GeV/
T
p 12 <
= 7 TeVsALICE, pp
|<0.5y meson, |
+
, D*
+
,D
0
A e age D
no shown〉η/dNd〈) / η/dN 6% unc. on (d±
+6%/-3% no maliza ion unc. no shown
〉η/d
ch
Nd〈) / η/d
ch
N (d
0 1 2 3 4 5 6 7 8 9
B eed-down unc.
0.4−
0.2−
0
0.2
0.4 1/2 (2) a low (high) mul iplici y×B ac ion hypo hesis:
(a) pTdependence.
)c<4 GeV/
T
p) in 2<
T
pdy/dN
2
Ra io o (d
0.5
1
1.5
2
2.5
3
3.5
4
c < 2 GeV/
T
p 1 <
c < 8 GeV/
T
p 4 <
c < 12 GeV/
T
p 8 <
c < 20 GeV/
T
p 12 <
= 7 TeVsALICE, pp
|<0.5y meson, |
+
, D*
+
,D
0
A e age D
no shown〉η/dNd〈) / η/dN 6% unc. on (d±
〉η/d
ch
Nd〈) / η/d
ch
N (d
0 1 2 3 4 5 6 7 8 9
B eed-down unc.
0.4−
0.2−
0
0.2
0.4 1/2 (2) a low (high) mul iplici y×B ac ion hypo hesis:
(b) Ra ios o pTin e als s he 2 < pT<4 GeV/c.
Figu e 4. A e age o D0, D+and D∗+ ela i e yields as a unc ion o he ela i e cha ged-
pa icle mul iplici y a cen al apidi y. (a) A e age o D-meson ela i e yields in pTin e als.
(b) Ra io o he a e age ela i e yields in all pTin e als wi h espec o ha o he 2 < pT<
4 GeV/c in e al. The esul s a e p esen ed in he op panels wi h hei s a is ical ( e ical ba s)
and sys ema ic (boxes) unce ain ies, excep o he eed-down ac ion unce ain y ha is d awn
sepa a ely in he bo om panels. The posi ion o he poin s on he abscissa is he a e age alue o
(dNch/dη)hdNch/dηi. Fo some pTin e als he poin s a e shi ed ho izon ally by 1.5% o imp o e
he isibili y. The dashed lines a e also shown o guide he eye, a diagonal on (a) and a cons an
on (b).
down ac ion e olu ion wi h he cha ged-pa icle mul iplici y is d awn sepa a ely in he
bo om panels. The poin s a e loca ed on he x-axis a he a e age alue o he ela i e
mean mul iplici y, NV0hNV0i. The unce ain y on he mean mul iplici y alues, NV0,
was de e mined by compa ing he mean and median alues o he dis ibu ions. I was
ound o be below 3% o each mul iplici y in e al, and abou 24% o he mul iplici y
in eg a ed alue. The unce ain y on NV0hNV0iis no displayed on his igu e. These
esul s a e also summa ised in ables 5and 6. The D0 ela i e yields inc ease wi h he el-
a i e unco ec ed mul iplici y a o wa d apidi y, as measu ed wi h he V0 de ec o . The
esul s in he 2 < pT<4 GeV/c and 4 < pT<8 GeV/c in e als a e compa ible wi hin
unce ain ies. The esul s wi h he V0 mul iplici y es ima o indica e ha he inc ease o
he D-meson yield wi h he e en mul iplici y obse ed wi h he mid- apidi y es ima o is
no ela ed o he ac ha cha med mesons, o igina ing om he agmen a ion o cha m
qua ks p oduced in ha d pa onic sca e ing p ocesses, and he cha ged pa icle mul iplici y
a e measu ed in he same pseudo- apidi y ange. A quali a i ely simila inc easing end
o D-meson yield wi h mul iplici y is indeed obse ed also when an ηgap is in oduced
be ween he egions whe e he D-mesons and he mul iplici y a e measu ed.
– 15 –
JHEP09(2015)148
〉
T
pdy/dN
2
d〈) /
T
pdy/dN
2
(d
1
2
3
4
5
6
7
c < 4 GeV/
T
p 2 <
c < 8 GeV/
T
p 4 <
= 7 TeVsALICE, pp
|<0.5y meson, |
0
D
no shown〉
V0
N〈 /
V0
N 3% unc. on ±
+6%/-3% no maliza ion unc. no shown
〉
V0
N〈 /
V0
N
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5
B eed-down unc.
0.4−
0.2−
0
0.2
0.4 1/2 (2) a low (high) mul iplici y×B ac ion hypo hesis:
Figu e 5. D0meson ela i e yields a |y|<0.5 o wo pTin e als as a unc ion o he ela i e
cha ged-pa icle mul iplici y, NV0, measu ed a −3.7< η < −1.7 and 2.8< η < 5.1. The ela i e
yields a e p esen ed on he op panels wi h hei s a is ical ( e ical ba s) and sys ema ic (boxes)
unce ain ies, excep he unce ain y on he eed-down ac ion which is d awn sepa a ely in he
bo om panels. The posi ion o he poin s on he abscissa is a he a e age alue o NV0hNV0i,
shi ed by 1.5% o imp o e he isibili y. The diagonal (dashed) line is also shown o guide he eye.
5 Non-p omp J/ψ analysis
5.1 Non-p omp J/ψ econs uc ion
The ac ion o non-p omp J/ψ in he inclusi e J/ψ yields, B, was measu ed as a unc ion
o he cha ged-pa icle mul iplici y by s udying displaced J/ψ mesons ha decay in o
elec on pai s in he apidi y ange |y|<0.9. This measu emen , combined wi h he
inclusi e J/ψ ela i e yield [40], p o ides he mul iplici y dependence o he p oduc ion o
beau y had ons. J/ψ candida es we e o med by combining pai s o opposi e-sign elec on
acks. The acks we e equi ed o ha e pT>1 GeV/c, a leas 70 (ou o a maximum o
159) associa ed space poin s in he TPC wi h a χ2/nd o he momen um i lowe han 2,
and o poin back o he p ima y in e ac ion e ex wi hin 1 cm in he ans e se plane.
The acks we e also equi ed o ha e a leas one associa ed hi in he SPD de ec o ,
wi h he cons ain ha one o he wo acks should ha e a hi in he i s SPD laye .
Elec on iden i ica ion was based only on he TPC in o ma ion. A selec ion o ±3σa ound
he expec ed mean alues o he speci ic ene gy deposi dE/dx o elec ons was used.
To u he educe he backg ound, a ±3.5σ(±3σ) exclusion band a ound he expec ed
mean speci ic ene gy deposi o pions (p o ons) was also applied. In o de o educe
he combina o ial backg ound, elec on candida es compa ible, oge he wi h a posi on
candida e, wi h being p oduc s o γ-con e sions (in a ian mass below 100 MeV/c2) we e
emo ed.
– 16 –
JHEP09(2015)148
The measu emen o Bis based on a s a is ical disc imina ion o J/ψ mesons p oduced
a a seconda y e ex displaced om he p ima y pp collision e ex. The signed p ojec ion
o he J/ψ ligh dis ance on o i s ans e se momen um ec o , ~pT, was cons uc ed as
Lxy =~
L·~pT/pT, whe e ~
Lis he ec o om he p ima y e ex o he J/ψ decay e ex.
The pseudo-p ope decay leng h x= (c·Lxy ·m)pTwas calcula ed om he obse ed
decay leng h using he wo ld-a e age J/ψ mass m(J/ψ) = 3096.916 ±0.011 MeV/c2[58].
The ac ion o non-p omp J/ψ can be de e mined om a 2-dimensional un-binned log-
likelihood i o xand he unlike-sign di-elec on in a ian mass dis ibu ions. The i
p ocedu e and he unc ions used o desc ibe he in a ian mass and he pseudo-p ope
decay leng h dis ibu ions we e in oduced in [10].
The ac ion o non-p omp J/ψ as a unc ion o he ela i e cha ged-pa icle mul i-
plici y was de e mined o pT>1.3 GeV/c in i e mul iplici y in e als in he N ackle s
ange [4,49]. The N ackle s ∈[1,3] ange was excluded om his analysis due o he poo
pseudo-p ope decay leng h esolu ion, R(x), and he p esence o a bias in he de e mi-
na ion o xin he case o non-p omp candida es. The esolu ion o he pseudo-p ope
decay leng h is de e mined wi h Mon e Ca lo simula ions e alua ing he RMS o he x
dis ibu ions o econs uc ed p omp ly p oduced J/ψ mesons. The e en p ima y e ex
can be compu ed wi h o wi hou emo ing he decay acks o he J/ψ candida es. The
emo al o he decay acks causes a deg ada ion o he esolu ion on x, especially in he
low-mul iplici y in e als, as a consequence o he lowe p ecision in he de e mina ion o
he p ima y e ex wi h a educed numbe o acks. Fo simula ed e en s wi h non-p omp
J/ψ, he emo al o he decay acks also esul s in a shi o he p ima y e ex posi ion
away om he seconda y decay e ex o he beau y had ons, which is e lec ed in a sys-
ema ic shi o he mean o he xdis ibu ion. Howe e , one should conside ha beau y
qua ks a e always p oduced in pai s: he wo decay acks om he non-p omp -J/ψ, when
included, pull he p ima y e ex owa ds he beau y had on decay e ex, bu he cha ged
acks om he decay o he second beau y qua k, which en e in he ba el accep ance,
pull he p ima y e ex in he opposi e di ec ion. The shi is la ge in he lowes mul i-
plici y bin whe e i eaches abou 35 µm. This bias is educed when he J/ψ decay acks
a e kep in he e alua ion o he p ima y e ex. The e ec o he bias, es ima ed wi h
Mon e Ca lo simula ions, is a educ ion1o he measu ed Bby abou 20% o e en s wi h
N ackle s = 4, and i becomes negligible o N ackle s >10. The e o e, he p ima y e ex
was compu ed conside ing all econs uc ed acks. To co ec o he emaining bias, a
modi ica ion in he esolu ion unc ion, R(x), used o desc ibe he non-p omp J/ψ in he
likelihood i unc ion was in oduced, which depends on N ackle s. In pa icula , he shape
o he esolu ion unc ion was adjus ed o ob ain a good ma ching be ween he unc ion
used o desc ibe he non-p omp J/ψ in he likelihood i (a con olu ion o a empla e o
he xdis ibu ion o J/ψ om beau y had on decays wi h he esolu ion unc ion [10]) and
he pseudo-p ope decay leng h dis ibu ion o econs uc ed seconda y J/ψ om Mon e
Ca lo simula ions.
1This shi would be g ea e han 50 µm in he N ackle s in e al [1,3], leading o a la ge bias on he
ex ac ed B alue (up o 35%). The co ec ion o his bias would in oduce a la ge sys ema ic unce ain y.
– 17 –
JHEP09(2015)148
2.4 2.6 2.8 3 3.2 3.4 3.6 3.8 4
)
2
cEn ies/(40 MeV/
2
4
6
8
10
12
14
16 = 7 TeVsALICE, pp
-1
= 5.6 nb
in
L
c)>1.3 GeV/ψ(J/
T
p|<0.9, y|
[4,8] ackle s
Da a
Fi , all
Fi , signal
Fi , backg ound
2.4 2.6 2.8 3 3.2 3.4 3.6 3.8 4
5
10
15
20
25
[9,13] ackle s
2.4 2.6 2.8 3 3.2 3.4 3.6 3.8 4
5
10
15
20
25
30
[14,19] ackle s
2.4 2.6 2.8 3 3.2 3.4 3.6 3.8 4
5
10
15
20
25
30
35
40
[20,30] ackle s
)
2
c) (GeV/
-
e
+
M(e
2.4 2.6 2.8 3 3.2 3.4 3.6 3.8 4
5
10
15
20
25
30
35
[31,49] ackle s
-2000 -1500 -1000 -500 0 500 1000 1500 2000
m)µEn ies/(40
-1
10
1
10
2
c) < 4.0 GeV/
-
e
+
(eM2.4 <
Da a
Fi , all
ψFi , p omp J/
ψFi , non-p omp J/
Fi , backg ound
-2000 -1500 -1000 -500 0 500 1000 1500 2000
-1
10
1
10
-2000 -1500 -1000 -500 0 500 1000 1500 2000
-1
10
1
10
-2000 -1500 -1000 -500 0 500 1000 1500 2000
-1
10
1
10
m)µPseudo-p ope decay leng h (
-2000 -1500 -1000 -500 0 500 1000 1500 2000
1
10
Figu e 6. J/ψ in a ian mass and pseudo-p ope decay leng h dis ibu ions in se e al mul iplici y
in e als wi h supe imposed he likelihood i esul s. The con ibu ions o he signal, he back-
g ound and hei sum a e ep esen ed wi h dashed, do -dashed and ull lines, espec i ely. In
addi ion, he pseudo-p ope decay leng h igu es include he p omp and non-p omp con ibu ions
o he inclusi e yields wi h do ed and long-dashed lines.
Figu e 6p esen s he in a ian mass and pseudo-p ope decay leng h dis ibu ions o
pT>1.3 GeV/c o each mul iplici y in e al oge he wi h a p ojec ion o he esul o
he log-likelihood i .
5.2 Co ec ions
Fo all mul iplici y in e als, he measu ed ac ion o non-p omp J/ψ, 0
B, was co ec ed
using he accep ance and econs uc ion e iciency o p omp , hAcc ×εip omp , and non-
p omp J/ψ,hAcc ×εiB, as
B=1 + 1− 0
B
0
B·hAcc ×εiB
hAcc ×εip omp −1
.(5.1)
– 18 –
JHEP09(2015)148
He e all e ms e e o non-p omp J/ψ wi h pT>1.3 GeV/c. The co ec ions o ac-
cep ance and e iciency we e compu ed using Mon e Ca lo simula ions using he GEANT3
anspo code [60]. P omp J/ψ we e gene a ed wi h a pTdis ibu ion ex apola ed om
CDF measu emen s [16] and a ydis ibu ion pa ame e ised wi h he Colou E apo a ion
Model (CEM) [62,63]. Beau y had ons we e gene a ed using he PYTHIA 6.4.21 e en
gene a o [30] wi h Pe ugia-0 une [64]. The accep ance imes e iciency alues o p omp
and non-p omp J/ψ ha e a minimum o 8% a pT= 2 GeV/c and a b oad maximum
o 12% a pT= 7 GeV/c [65]. The ela i e di e ence in e iciency be ween p omp and
non-p omp J/ψ is only abou 3%. The a io hAcc ×εiB/hAcc ×εip omp is assumed o be
independen o mul iplici y. The unce ain y ela ed o his assump ion is discussed in he
nex sec ion.
The measu ed non-p omp J/ψ ac ions we e ex apola ed om pT>1.3 GeV/c down
o pT= 0 using
ex
B(pT>0) = αex · B(pT>1.3 GeV/c); αex = model
B(pT>0)
model
B(pT>1.3 GeV/c),(5.2)
whe e model
B ep esen s a unc ional o m modelled on exis ing da a. I was calcula ed
as he a io o he di e en ial c oss sec ion o non-p omp J/ψ, as ob ained wi h FONLL
calcula ions [7], o ha o inclusi e J/ψ, pa ame e ised by he phenomenological unc ion
de ined in [66]:
model
B(pT) = d2σFONLL
J/ψ←hB
dydpT,d2σphenom
J/ψ
dydpT
.(5.3)
A combined i o he exis ing esul s o Bin pp collisions a 7 TeV [10,13,67,68] in he
apidi y bin closes o cen al apidi y was pe o med o de e mine he pa ame e s o he
phenomenological pa ame e isa ion. The ex apola ion ac o ob ained is αex = 0.99+0.01
−0.03.
I s unce ain ies we e de e mined by epea ing he i by (i) excluding he LHCb da a poin s
a o wa d apidi ies, and (ii) using o he non-p omp J/ψ c oss sec ion he uppe and
lowe unce ain y bands o he FONLL p edic ions, ob ained by a ying he ac o isa ion
and eno malisa ion scales, ins ead o he cen al alues. The unce ain ies we e de e mined
by he maximum and minimum αex alues ob ained om hese i a ia ions. The B
ac ions in all mul iplici y in e als we e ex apola ed using he same αex alue, e alua ed
om he i o he mul iplici y in eg a ed measu emen s.
5.3 Sys ema ic unce ain ies
The sys ema ic unce ain y in oduced by he expe imen al esolu ion on he p ima y e -
ex posi ion was e alua ed by epea ing he i ing p ocedu e in wo al e na i e ways: (i)
he p ima y e ex was e alua ed wi hou emo ing he decay acks o he J/ψ candi-
da es. The i was pe o med using he s anda d esolu ion unc ion o non-p omp J/ψ,
ha does no depend on mul iplici y, bu he xdis ibu ion o he non-p omp J/ψ was
shi ed by a mul iplici y-dependen alue, which was de e mined by he Mon e Ca lo sim-
ula ion. (ii) The e en p ima y e ex was compu ed a e emo ing he decay acks o
he J/ψ candida es and he i was pe o med using he co esponding deg aded esolu ion
– 19 –
JHEP09(2015)148
unc ion R(x) and wi hou any shi . The esul ing unce ain ies dec ease wi h inc eas-
ing mul iplici y, anging om 19% in he lowes mul iplici y in e al o 3% a he highes
mul iplici ies.
The unce ain y ela ed o he ex apola ion o B om pT>1.3 GeV/c o pT>0
was es ima ed wi h he me hod discussed abo e and i is abou 3%. This unce ain y was
assumed o be unco ela ed among he mul iplici y in e als.
The esolu ion unc ion used in he i s is based on Mon e Ca lo simula ions, which
migh in oduce sys ema ic e ec s. These we e es ima ed by epea ing he log-likelihood
i s modi ying he esolu ion unc ion, R(x), acco ding o (1/(1 + δ))·R(x/(1 + δ)), whe e
δis he ela i e a ia ion o he RMS o he esolu ion unc ion, and i was a ied om
−0.1 o +0.1 o ake in o accoun he unce ain ies in he Mon e Ca lo desc ip ion. The
sys ema ic unce ain y due o he esolu ion unc ion inc eases wi h mul iplici y om 8%
o 20%.
The pTdis ibu ion o he signal candida es (p omp and non-p omp J/ψ) could
depend on he e en mul iplici y which could a ec he shape o he esolu ion unc ion
which depends on he J/ψ pT. The a e age pTo he signal candida es was es ima ed om
da a in each mul iplici y in e al and ound o be cons an as a unc ion o e en mul iplici y
wi hin s a is ical unce ain ies abou ±10%. The in luence o a hpTi a ia ion on he
esolu ion unc ion was de e mined using Mon e Ca lo simula ions: he pTdis ibu ion
was changed, conside ing so e o ha de pTdis ibu ions, in o de o ob ain a ±10%
a ia ion o he hpTi. The co esponding a ia ions ob ained o he RMS o he esolu ion
unc ion a e +7% and −8.5% o he so e and ha de pTdis ibu ion, espec i ely. The
la e a ia ions a e wi hin hose quo ed o he esolu ion unc ion (±10%), he e o e no
addi ional unce ain y was included.
The accep ance imes e iciency alues o p omp and non-p omp J/ψ econs uc ed
o pT>1.3 GeV/c a e o he o de o 10% and di e by 3%. The in luence o he pT
shape assumed in he simula ion on he a io hAcc ×εiB/hAcc ×εip omp was e alua ed by
a ying he a e age pTo he simula ed J/ψ dis ibu ions wi hin ±50%. A 1% a ia ion
in he accep ance was ob ained bo h o p omp and non-p omp J/ψ. The co esponding
a ia ion ob ained on B h ough he eq. (5.1) is abou 1%.
The pseudo-p ope decay leng h shape o he combina o ial backg ound was de e -
mined by a i o he xdis ibu ion o he candida es in he sidebands o he in a ian
mass [10]. By a ying he i pa ame e s wi hin hei e o s an en elope o dis ibu ions
was ob ained, whose ex emes we e used in he likelihood i o es ima e he sys ema ic
unce ain y. I inc eases sligh ly wi h mul iplici y, anging om 1% o 5%.
The unce ain y on he backg ound in a ian mass shape, which was de e mined by
i s o he in a ian mass dis ibu ions o opposi e-sign candida es in each mul iplici y bin,
was e alua ed by using like-sign dis ibu ions ins ead, adop ing he same p ocedu e as
desc ibed in [10]. The sys ema ic unce ain y is abou 7%, independen o he cha ged-
pa icle mul iplici y.
The shape o he xdis ibu ion o J/ψ om b-had ons was e alua ed using PYTHIA
6.4.21 [30]. The sys ema ic unce ain y on i s shape was compu ed by (i) changing he
b-had on decay kinema ic, using E Gen [61] ins ead o PYTHA 6.4.21 o (ii) by assuming
– 20 –
JHEP09(2015)148
a ha de and a so e b-had on pTdis ibu ion, esul ing in a hpTi a ia ion o abou ±15%.
The esul ing sys ema ic unce ain y is abou 3%, cons an wi h mul iplici y.
The signal in a ian mass shape was ixed om he Mon e Ca lo simula ion which
includes he de ec o esolu ion e ec s and he adia i e decays using he E Gen [61]
package. The e ec on he in a ian mass signal shape due o he unce ain y on he
de ec o ma e ial was s udied wi h dedica ed Mon e Ca lo simula ions, whe e he de ec o
ma e ial budge was a ied by ±6% wi h espec o he nominal alues [69,70]. The
esul ing sys ema ic unce ain y on Bis 3% in he lowes e en mul iplici y in e al and
5% in he highes one.
The sys ema ic unce ain ies on he pseudo-p ope decay leng h o he combina o ial
backg ound, on he pT-ex apola ion unce ain y αex and on he in a ian mass shape o
backg ound a e ound o , in he case o αex , assumed o be unco ela ed among mul i-
plici y in e als. The emaining sys ema ic unce ain ies a e ( ully o pa ially) co ela ed
in di e en mul iplici y in e als.
5.4 Resul s
The ela i e yield o J/ψ om beau y had on decays as a unc ion o he cha ged-pa icle
mul iplici y was e alua ed om he inclusi e J/ψ yield and he ac ion o non-p omp J/ψ
pe mul iplici y in e al:
dNnon−p omp
J/ψ /dy
DdNnon−p omp
J/ψ /dyE=dNJ/ψ/dy
dNJ/ψ/dy· B
h Bi.(5.4)
Bis he ac ion o non-p omp J/ψ in each mul iplici y in e al, h Biis he ac ion in
he mul iplici y in eg a ed sample [10], and (dNJ/ψ/dy)hdNJ/ψ/dyiis he inclusi e J/ψ
ela i e yield measu ed o pT>0 in each mul iplici y in e al no malized o i s alue in
inelas ic pp collisions [40]. All hese quan i ies we e measu ed using he same da a sam-
ple and he s a is ical co ela ions we e aken in o accoun . In he i s cha ged-pa icle
mul iplici y class N ackle s ∈[4,8], which is used o he non-p omp J/ψ analysis p e-
sen ed he e, he ela i e yield o inclusi e J/ψ no malized o he inelas ic c oss sec ion is
(dNJ/ψ/dy)hdNJ/ψ/dyi= 0.41±0.07 (s a )±0.01 (sys ). The alues o Bex apola ed o
pT>0 we e used in eq. (5.4), p o iding he non-p omp J/ψ ela i e yields o pT>0. The
ela i e yields o inclusi e J/ψ we e also ecompu ed o pT>1.3 GeV/c and no di e ence
was obse ed wi h espec o hose o pT>0 wi hin he unce ain ies.
The esul s o he ac ion o non-p omp J/ψ o bo h pT>0 and pT>1.3 GeV/c,
he ela i e yields o p omp and non-p omp J/ψ in each mul iplici y bin o pT>0 a e
summa ized in ables 7and 8and shown in igu e 7.
6 Compa ison o cha m and beau y p oduc ion
Figu e 8(a) p esen s p omp D meson and inclusi e J/ψ esul s o compa e open and
hidden cha m p oduc ion. The a e age p omp D-meson esul s a e shown in he 2 <
– 21 –
JHEP09(2015)148
〉
η
/d
ch
Nd〈) /
η
/d
ch
N(d
0 1 2 3 4 5
om b had ons (%)ψF ac ion o J/
0
10
20
30
40
50
= 7 TeVsALICE, pp
c) > 1.3 GeV/ψ(J/
T
p| < 0.9, y|
Figu e 7. Non-p omp J/ψ ac ion as a unc ion o he ela i e cha ged-pa icle mul iplici y a cen-
al apidi y o pT>1.3 GeV/c. The e ical ba s ep esen he s a is ical unce ain ies, while he
emp y boxes s and o he sys ema ic unce ain ies. The wid h and he heigh o hese emp y boxes
indica e he measu emen unce ain y on he ho izon al and e ical axis espec i ely. The dashed
line shows he alue o Bmeasu ed in he same pT ange and in eg a ed o e mul iplici y [10]. The
shaded a ea ep esen s he s a is ical and sys ema ic unce ain ies on he mul iplici y-in eg a ed
esul added in quad a u e.
pT<4 GeV/c in e al wi h he pT-in eg a ed inclusi e J/ψ measu emen 2a cen al and
o wa d- apidi y by he ALICE expe imen [40]. The esul s o p omp J/ψ a cen al
apidi y om his pape (pT>0) and o p omp D mesons (2 < pT<4 GeV/c) a e
compa ed in igu e 8(b). A simila inc ease o he ela i e yield wi h he cha ged-pa icle
mul iplici y is obse ed o open and hidden cha m p oduc ion bo h a cen al and o wa d
apidi ies.
Figu e 8(c) supe imposes he open cha m and beau y p oduc ion measu emen s e-
po ed in his pape showing he a e age p omp D-meson esul s in he 2 < pT<4 GeV/c
in e al and he pT-in eg a ed non-p omp J/ψ measu emen a cen al apidi y. The e-
sul s a e compa ible wi hin he measu emen unce ain ies.
Open cha m, open beau y and hidden cha m had on ela i e yields p esen a simila in-
c ease wi h cha ged-pa icle mul iplici y. The compa ison o open and hidden hea y la ou
p oduc ion sugges s ha his beha iou is mos likely ela ed o he c¯c and b¯
b p oduc ion
p ocesses, and is no signi ican ly in luenced by had onisa ion. The enhancemen o he
hea y- la ou ela i e yields wi h he cha ged-pa icle mul iplici y is quali a i ely consis-
en wi h he calcula ions o he con ibu ion om MPIs o pa icle p oduc ion a LHC
2A e he inclusi e J/ψ measu emen was published in e e ence [40], he e was an imp o emen o he
ALICE measu emen o he inelas ic c oss sec ion in pp collisions a √s= 7 TeV. The imp o ed e alua ion
o he inelas ic c oss sec ion does no ely on Mon e Ca lo, hence he sys ema ic unce ain y is la ge [56].
To allow a p ope compa ison wi h he esul s epo ed he e, we upda ed he published inclusi e J/ψ
measu emen by he co esponding change o he igge e iciency o inelas ic collisions 0.864/0.85. The
no malisa ion unce ain ies we e also changed om 1.5% o +6
−3%.
– 22 –
JHEP09(2015)148
〉
T
pdy/dN
2
d〈) /
T
pdy/dN
2
(d
5
10
15
20
25
c<4 GeV/
T
p|<0.5, 2<y meson |
+
, D*
+
, D
0
A e age D
>0
T
p|<0.9, y, |
-
e
+
e→ ψJ/
>0
T
p<4.0, y, 2.5<
-
µ
+
µ → ψJ/
= 7 TeVsALICE, pp
no shown〉η/dNd〈) / η/dN 6% unc. on (d±
+6%/-3% no maliza ion unc. no shown
〉η/d
ch
Nd〈) / η/d
ch
N (d
0 1 2 3 4 5 6 7 8 9
B eed-down unc.
0.4−
0.2−
0
0.2
0.4 1/2 (2) a low (high) mul iplici y×B ac ion hypo hesis:
(a) D meson wi h 2 < pT<4 GeV/c and
inclusi e J/ψ.
〉
T
pdy/dN
2
d〈) /
T
pdy/dN
2
(d
5
10
15
20
25
c<4 GeV/
T
p|<0.5, 2<y meson |
+
, D*
+
, D
0
A e age D
>0
T
p|<0.9, y, |
-
e
+
e→ ψP omp J/
= 7 TeVsALICE, pp
no shown〉η/dNd〈) / η/dN 6% unc. on (d±
+6%/-3% no maliza ion unc. no shown
〉η/d
ch
Nd〈) / η/d
ch
N (d
0 1 2 3 4 5 6 7 8 9
B eed-down unc.
0.4−
0.2−
0
0.2
0.4 1/2 (2) a low (high) mul iplici y×B ac ion hypo hesis:
(b) D meson wi h 2 < pT<4 GeV/c and
p omp J/ψ.
〉
T
pdy/dN
2
d〈) /
T
pdy/dN
2
(d
5
10
15
20
25
c<4 GeV/
T
p|<0.5, 2<y meson |
+
, D*
+
, D
0
A e age D
>0
T
p|<0.9, y, |
-
e
+
e→ ψNon-p omp J/
= 7 TeVsALICE, pp
no shown〉η/dNd〈) / η/dN 6% unc. on (d±
+6%/-3% no maliza ion unc. no shown
〉η/d
ch
Nd〈) / η/d
ch
N (d
0 1 2 3 4 5 6 7 8 9
B eed-down unc.
0.4−
0.2−
0
0.2
0.4 1/2 (2) a low (high) mul iplici y×B ac ion hypo hesis:
(c) D meson wi h 2 < pT<4 GeV/c and
non-p omp J/ψ.
Figu e 8. A e age D meson and J/ψ ela i e yields as a unc ion o he ela i e cha ged-pa icle
mul iplici y a cen al apidi y. D-meson yields a e shown o 2 < pT<4 GeV/c, while J/ψ yields
a e o pT>0. (a) Inclusi e J/ψ esul s o |y|<0.9 a e ep esen ed by emp y black ci cles [40],
inclusi e J/ψ esul s o 2.5< y < 4.0 by black illed symbols [40], and p omp D mesons by ed
illed ci cles. (b) P omp J/ψ esul s o |y|<0.9 a e ep esen ed by g een illed c osses, and
p omp D mesons by ed illed ci cles. (c) Non-p omp J/ψ esul s o |y|<0.9 a e ep esen ed
by blue illed squa es, and p omp D mesons by ed illed ci cles. The ela i e yields a e p esen ed
on he op panels wi h hei s a is ical ( e ical ba s) and sys ema ic (boxes) unce ain ies excep
he unce ain y on he eed-down ac ion o D mesons, which is d awn sepa a ely on he bo om
panels. The poin s a e loca ed on he x-axis a he a e age alue o (dNch/dη)hdNch/dηi. The
diagonal (dashed) line is d awn o guide he eye.
– 23 –
JHEP09(2015)148
e e , he PYTHIA 8.157 [31] e en gene a o seems o unde -es ima e he inc ease o hea y
la ou yields wi h he cha ged-pa icle mul iplici y a high mul iplici ies.
Acknowledgmen s
We would like o hank P. Skands, co-au ho o PYTHIA 8, and K. We ne and B. Guio , co-
au ho s o EPOS 3, o ui ul discussions and o p o iding hei heo e ical calcula ions.
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 : S a e Commi ee o Science, Wo ld Fede a ion o Scien is s (WFS) and
Swiss Fonds Kidagan, A menia, Conselho Nacional de Desen ol imen o Cien ´ı ico e Tec-
nol´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); Na ional Na u al Science Founda ion o China
(NSFC), he Chinese Minis y o Educa ion (CMOE) and he Minis y o Science and Tech-
nology o China (MSTC); Minis y o Educa ion and You h o he Czech Republic; Danish
Na u al Science Resea ch Council, he Ca lsbe g Founda ion and he Danish Na ional Re-
sea ch Founda ion; The Eu opean Resea ch Council unde he Eu opean Communi y’s
Se en h F amewo k P og amme; Helsinki Ins i u e o Physics and he Academy o Fin-
land; F ench CNRS-IN2P3, he ‘Region Pays de Loi e’, ‘Region Alsace’, ‘Region Au e gne’
and CEA, F ance; Ge man Bundesminis e ium u Bildung, Wissenscha , Fo schung und
Technologie (BMBF) and he Helmhol z Associa ion; Gene al Sec e a ia o Resea ch and
Technology, Minis y o De elopmen , G eece; Hunga ian O szagos Tudomanyos Ku a asi
Alappg ammok (OTKA) and Na ional O ice o Resea ch and Technology (NKTH); De-
pa men o A omic Ene gy and Depa men o Science and Technology o he Go e nmen
o India; Is i u o Nazionale di Fisica Nuclea e (INFN) and Cen o Fe mi — Museo S o ico
della Fisica e Cen o S udi e Rice che “En ico Fe mi”, I aly; MEXT G an -in-Aid o
Specially P omo ed Resea ch, Japan; Join Ins i u e o Nuclea Resea ch, Dubna; Na-
ional Resea ch Founda ion o Ko ea (NRF); Consejo Nacional de Cienca y Tecnologia
(CONACYT), Di eccion Gene al de Asun os del Pe sonal Academico(DGAPA), M´exico,
Ame ique La ine Fo ma ion academique — Eu opean Commission (ALFA-EC) and he
EPLANET P og am (Eu opean Pa icle Physics La in Ame ican Ne wo k); S ich ing oo
Fundamen eel Onde zoek de Ma e ie (FOM) and he Nede landse O ganisa ie oo We en-
schappelijk Onde zoek (NWO), Ne he lands; Resea ch Council o No way (NFR); Na ional
Science Cen e, Poland; Minis y o Na ional Educa ion/Ins i u e o A omic Physics and
Na ional Council o Scien i ic Resea ch in Highe Educa ion (CNCSI-UEFISCDI), Ro-
mania; Minis y o Educa ion and Science o Russian Fede a ion, Russian Academy o
Sciences, Russian Fede al Agency o A omic Ene gy, Russian Fede al Agency o Science
and Inno a ions and The Russian Founda ion o Basic Resea ch; Minis y o Educa ion
o Slo akia; Depa men o Science and Technology, Sou h A ica; Cen o de In es iga-
– 30 –
JHEP09(2015)148
ciones Ene ge icas, Medioambien ales y Tecnologicas (CIEMAT), E-In as uc u e sha ed
be ween Eu ope and La in Ame ica (EELA), Minis e io de Econom´ıa y Compe i i idad
(MINECO) o Spain, Xun a de Galicia (Conselle ´ıa de Educaci´on), Cen o de Aplicaciones
Tecnol´ogicas y Desa ollo Nuclea (CEADEN), Cubaene g´ıa, Cuba, and IAEA (In e na-
ional A omic Ene gy Agency); Swedish Resea ch Council (VR) and Knu & Alice Wal-
lenbe g Founda ion (KAW); Uk aine Minis y o Educa ion and Science; Uni ed Kingdom
Science and Technology Facili ies Council (STFC); The Uni ed S a es Depa men o En-
e gy, he Uni ed S a es Na ional Science Founda ion, he S a e o Texas, and he S a e o
Ohio; Minis y o Science, Educa ion and Spo s o C oa ia and Uni y h ough Knowledge
Fund, C oa ia. Council o Scien i ic and Indus ial Resea ch (CSIR), New Delhi, India.
A Tables o he esul s
Table 4 epo s he esul s o he ela i e a e age D-meson yields pe inelas ic collision as
a unc ion o he ela i e cha ged-pa icle mul iplici y a mid- apidi y in se e al D-meson
ans e se momen um in e als, see igu e 4. The co esponding ela i e a e age D-meson
yields no malised o he isible c oss sec ion ins ead o he inelas ic one a e p esen ed in
able 3.
Table 6summa ises he ela i e D0yields pe inelas ic collision as a unc ion o he
ela i e aw mul iplici y measu ed wi h he V0 de ec o a o wa d apidi y, see igu e 5.
These ela i e D0yields a e also p esen ed in able 5no malised o he isible c oss sec ion.
Table 7 epo s he ac ion o non-p omp J/ψ o he inclusi e J/ψ yields as a unc ion
o he ela i e cha ged-pa icle mul iplici y a mid- apidi y, see igu e 7. The ela i e
p omp and non-p omp J/ψ yields pe inelas ic collision a e epo ed in able 8, while
able 7p esen s hese yields no malised o he isible c oss sec ion.
– 31 –
JHEP09(2015)148
N ackle s in e al
[1,8] [9,13] [14,19] [20,30] [31,49] [50,80]
pT(GeV/c) (d2N/dydpT)hd2N/dydpTi× igge
1–2 0.39 ±0.09 ±0.05+0.07
−00.94 ±0.21 ±0.11+0.14
−0.07 1.45 ±0.36 ±0.15+0.16
−0.22 3.60 ±0.66 ±0.40+0.27
−0.82 5.33 ±1.59 ±0.62+0
−2.01 —
2–4 0.18 ±0.01 ±0.01+0.02
−00.91 ±0.05 ±0.06+0.07
−0.03 1.94 ±0.10 ±0.11+0.10
−0.14 3.64 ±0.16 ±0.15+0.13
−0.40 7.67 ±0.48 ±0.40+0
−1.42 14.04 ±2.21 ±1.79+0
−3.28
4–8 0.15 ±0.01 ±0.01+0.01
−01.01 ±0.04 ±0.06+0.06
−0.03 1.95 ±0.08 ±0.10+0.09
−0.12 4.13 ±0.12 ±0.22+0.12
−0.35 9.36 ±0.39 ±0.45+0
−1.49 16.94 ±1.60 ±1.45+0
−3.15
8–12 0.14 ±0.02 ±0.01+0.01
−00.69 ±0.07 ±0.05+0.04
−0.02 2.41 ±0.15 ±0.15+0.11
−0.15 4.27 ±0.25 ±0.26+0.14
−0.42 8.74 ±0.72 ±0.57+0
−1.48 —
12–20 — — 2.14 ±0.30 ±0.26+0.07
−0.10 4.15 ±0.51 ±0.43+0.09
−0.28 11.60 ±1.59 ±1.18+0
−1.31 —
Table 3. A e age o D0, D+and D∗+mesons ela i e yields o he sum o pa icle and an ipa icle in se e al mul iplici y and pTin e als o
pp collisions a √s= 7 TeV as a unc ion o he ela i e cha ged-pa icle mul iplici y a cen al apidi y. The alues a e epo ed oge he wi h
hei unce ain ies, which a e quo ed in he he o de : s a is ical, sys ema ic and eed-down con ibu ion unce ain ies. The yields epo ed he e
a e no co ec ed by he igge selec ion e iciency, hey a e no malised o he isible c oss sec ion.
(dNch/dη)hdNch/dηi
0.45+0.03
−0.03 1.18+0.07
−0.07 1.78+0.10
−0.11 2.63+0.15
−0.17 4.01+0.23
−0.25 6.11+0.35
−0.39
pT(GeV/c) (d2N/dydpT)hd2N/dydpTi
1–2 0.45 ±0.11 ±0.05+0.09
−01.11 ±0.25 ±0.13+0.17
−0.08 1.70 ±0.43 ±0.18+0.19
−0.26 4.24 ±0.78 ±0.47+0.32
−0.96 6.27 ±1.87 ±0.73+0
−2.37 —
2–4 0.21 ±0.02 ±0.01+0.02
−01.08 ±0.06 ±0.06+0.08
−0.04 2.28 ±0.12 ±0.13+0.12
−0.16 4.28 ±0.19 ±0.17+0.16
−0.48 9.02 ±0.57 ±0.47+0
−1.67 16.51 ±2.60 ±2.11+0
−3.86
4–8 0.18 ±0.01 ±0.01+0.01
−01.18 ±0.05 ±0.07+0.07
−0.04 2.30 ±0.09 ±0.12+0.11
−0.14 4.85 ±0.15 ±0.26+0.14
−0.42 11.02 ±0.46 ±0.53+0
−1.75 19.92 ±1.89 ±1.71+0
−3.71
8–12 0.16 ±0.02 ±0.01+0.01
−0.00 0.81 ±0.08 ±0.06+0.05
−0.03 2.84 ±0.17 ±0.18+0.13
−0.17 5.02 ±0.29 ±0.31+0.17
−0.50 10.28 ±0.85 ±0.67+0
−1.74 —
12–20 — — 2.52 ±0.35 ±0.30+0.09
−0.11 4.88 ±0.61 ±0.51+0.11
−0.33 13.65 ±1.87 ±1.38+0
−1.54 —
Table 4. A e age o D0, D+and D∗+mesons ela i e yields o he sum o pa icle and an ipa icle in se e al mul iplici y and pTin e als o
pp collisions a √s= 7 TeV as a unc ion o he ela i e cha ged-pa icle mul iplici y a cen al apidi y. The alues a e epo ed oge he wi h
hei unce ain ies, which a e quo ed in he he o de : s a is ical, sys ema ic and eed-down con ibu ion unce ain ies. The yields epo ed he e
a e pe inelas ic e en .
– 32 –
JHEP09(2015)148
NV0hNV0i
0.43 1.0 1.5 2.2 3.3
pT(GeV/c) (d2N/dydpT)hd2N/dydpTi× igge
2–4 0.15 ±0.02 ±0.01+0.02
−00.65 ±0.07 ±0.03+0.06
−0.03 1.28 ±0.11 ±0.07+0.09
−0.12 2.81 ±0.15 ±0.11+0.13
−0.39 4.22 ±0.33 ±0.24+0
−0.99
4–8 0.17 ±0.02 ±0.01+0.02
−00.80 ±0.07 ±0.04+0.07
−0.04 1.50 ±0.12 ±0.08+0.10
−0.13 2.57 ±0.15 ±0.14+0.11
−0.34 4.53 ±0.34 ±0.24+0
−1.00
Table 5. D0meson ela i e yields o he sum o pa icle and an ipa icle in se e al mul iplici y and pTin e als o pp collisions a √s= 7 TeV
as a unc ion o he ela i e a e age mul iplici y in he V0 de ec o , NV0hNV0i. The yields epo ed he e a e no co ec ed by he igge selec ion
e iciency, hey a e no malised o he isible c oss sec ion.
NV0hNV0i
0.43 1.0 1.5 2.2 3.3
pT(GeV/c) (d2N/dydpT)hd2N/dydpTi
2–4 0.18 ±0.02 ±0.01+0.02
−00.76 ±0.08 ±0.04+0.07
−0.04 1.50 ±0.13 ±0.08+0.11
−0.14 3.31 ±0.18 ±0.13+0.15
−0.46 4.96 ±0.38 ±0.28+0
−1.16
4–8 0.20 ±0.02 ±0.01+0.02
−00.94 ±0.09 ±0.05+0.08
−0.04 1.76 ±0.14 ±0.09+0.12
−0.16 3.02 ±0.18 ±0.16+0.13
−0.40 5.33 ±0.40 ±0.29+0
−1.18
Table 6. D0meson ela i e yields o he sum o pa icle and an ipa icle in se e al mul iplici y and pTin e als o pp collisions a √s= 7 TeV
as a unc ion o he ela i e a e age mul iplici y in he V0 de ec o , NV0hNV0i. The yields epo ed he e a e no malised o he inelas ic c oss
sec ion.
– 33 –
JHEP09(2015)148
N ackle s B(%) ex
B(%) (dNp omp
J/ψ /dy)hdNp omp
J/ψ /dyi× igge (dNnon−p omp
J/ψ /dy)hdNnon−p omp
J/ψ /dyi× igge
[4,8] 10.1±7.8±2.5 10.2±7.9±2.5 0.37 ±0.07 ±0.01 0.24 ±0.20+0.05
−0.04
[9,13] 20.8±6.9±2.7 20.9±6.9±2.7 0.80 ±0.14 ±0.04 1.20 ±0.39+0.19
−0.14
[14,19] 15.6±6.3±2.0 15.7±6.3±2.0 1.95 ±0.31 ±0.24 2.06 ±0.84+0.37
−0.35
[20,30] 16.7±6.7±3.3 16.8±6.7±3.3 2.61 ±0.46 ±0.27 2.99 ±1.23+0.51
−0.47
[31,49] 19.0±11.9±4.2 19.0±12.0±4.2 6.50 ±1.50 ±0.31 8.70 ±5.75+1.41
−1.24
Table 7. F ac ion o non-p omp J/ψ measu ed o pT>1.3 GeV/c, B(%), and ex apola ed
down o pT>0, ex
B(%) in he a ious N ackle s in e als. P omp and non-p omp J/ψ ela i e
yields o pT>0 a e also epo ed in he di e en mul iplici y in e als. The i s and second
unce ain ies co espond o he s a is ical and sys ema ic unce ain ies, espec i ely. The yields
epo ed he e a e no co ec ed by he igge selec ion e iciency, hey a e no malised o he isible
c oss sec ion.
(dNch/dη)hdNch/dηi(dNp omp
J/ψ /dy)hdNp omp
J/ψ /dyi(dNnon−p omp
J/ψ /dy)hdNnon−p omp
J/ψ /dyi
0.63+0.4
−0.40.44 ±0.08 ±0.01 0.28 ±0.23+0.06
−0.05
1.18+0.07
−0.07 0.94 ±0.17 ±0.05 1.41 ±0.46+0.22
−0.17
1.78+0.10
−0.11 2.29 ±0.36 ±0.28 2.42 ±0.99+0.44
−0.41
2.63+0.15
−0.17 3.07 ±0.54 ±0.32 3.52 ±1.45+0.60
−0.55
4.01+0.23
−0.25 7.65 ±1.76 ±0.36 10.24 ±6.76+1.66
−1.46
Table 8. P omp and non-p omp J/ψ ela i e yields o pT>0 in di e en mul iplici y bins. The
i s and second unce ain ies co espond o he s a is ical and sys ema ic unce ain ies espec i ely.
The yields epo ed he e a e no malised o he inelas ic c oss sec ion.
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(2015)148
The ALICE collabo a ion
J. Adam40 , D. Adamo ´a83 , M.M. Agga wal87 , G. Aglie i Rinella36 , M. Agnello111 ,
N. Ag awal48 , Z. Ahammed131 , I. Ahmed16 , S.U. Ahn68 , I. Aimo94 ,111 , S. Aiola136 ,
M. Ajaz16 , A. Akindino 58 , S.N. Alam131 , D. Aleksand o 100 , B. Alessand o111 ,
D. Alexand e102 , R. Al a o Molina64 , A. Alici105 ,12 , A. Alkin3, J. Alme38 , T. Al 43 ,
S. Al inpina 18 , I. Al sybee 130 , C. Al es Ga cia P ado119 , C. And ei78 , A. And onic97 ,
V. Anguelo 93 , J. Anielski54 , T. An iˇci´c98 , F. An ino i108 , P. An onioli105 , L. Aphece che113 ,
H. Appelsh¨ause 53 , S. A celli28 , N. A mes o17 , R. A naldi111 , T. A onsson136 , I.C. A sene22 ,
M. A slandok53 , A. Augus inus36 , R. A e beck97 , M.D. Azmi19 , M. Bach43 , A. Badal`a107 ,
Y.W. Baek44 , S. Bagnasco111 , R. Bailhache53 , R. Bala90 , A. Baldisse i15 , M. Ball92 ,
F. Bal asa Dos San os Ped osa36 , R.C. Ba al61 , A.M. Ba bano111 , R. Ba be a29 , F. Ba ile33 ,
G.G. Ba na ¨oldi135 , L.S. Ba nby102 , V. Ba e 70 , P. Ba alini7, J. Ba ke116 , E. Ba sch53 ,
M. Basile28 , N. Bas id70 , S. Basu131 , B. Ba hen54 , G. Ba igne113 , A. Ba is a Camejo70 ,
B. Ba yunya66 , P.C. Ba zing22 , I.G. Bea den80 , H. Beck53 , C. Bedda111 , N.K. Behe a48 ,
I. Beliko 55 , F. Bellini28 , H. Bello Ma inez2, R. Bellwied121 , R. Belmon 134 ,
E. Belmon -Mo eno64 , V. Belyae 76 , G. Bencedi135 , S. Beole27 , I. Be ceanu78 , A. Be cuci78 ,
Y. Be dniko 85 , D. Be enyi135 , R.A. Be ens57 , D. Be zano36 ,27 , L. Be e 36 , A. Bhasin90 ,
I.R. Bha 90 , A.K. Bha i87 , B. Bha acha jee45 , J. Bhom127 , L. Bianchi27 ,121 , N. Bianchi72 ,
C. Bianchin134 ,57 , J. Bielˇc´ık40 , J. Bielˇc´ıko ´a83 , A. Bilandzic80 , S. Biswas79 , S. Bjelog lic57 ,
F. Blanco10 , D. Blau100 , C. Blume53 , F. Bock74 ,93 , A. Bogdano 76 , H. Bøggild80 ,
L. Boldizs´a 135 , M. Bomba a41 , J. Book53 , H. Bo el15 , A. Bo isso 96 , M. Bo i82 , F. Boss´u65 ,
M. Bo je81 , E. Bo a27 , S. B¨o ge 52 , P. B aun-Munzinge 97 , M. B egan 119 , T. B ei ne 52 ,
T.A. B oke 53 , T.A. B owning95 , M. B oz40 , E.J. B ucken46 , E. B una111 , G.E. B uno33 ,
D. Budniko 99 , H. Buesching53 , S. Bu alino36 ,111 , P. Buncic36 , O. Busch93 , Z. Bu helezi65 ,
J.T. Bux on20 , D. Ca a i36 ,30 , X. Cai7, H. Caines136 , L. Cale o Diaz72 , A. Cali a57 ,
E. Cal o Villa 103 , P. Came ini26 , F. Ca ena36 , W. Ca ena36 , J. Cas illo Cas ellanos15 ,
A.J. Cas o124 , E.A.R. Casula25 , C. Ca icchioli36 , C. Ceballos Sanchez9, J. Cepila40 ,
P. Ce ello111 , B. Chang122 , S. Chapeland36 , M. Cha ie 123 , J.L. Cha e 15 ,
S. Cha opadhyay131 , S. Cha opadhyay101 , V. Chelnoko 3, M. Che ney86 , C. Cheshko 129 ,
B. Cheynis129 , V. Chiban e Ba oso36 , D.D. Chinella o120 , P. Chochula36 , K. Choi96 ,
M. Chojnacki80 , S. Choudhu y131 , P. Ch is akoglou81 , C.H. Ch is ensen80 , P. Ch is iansen34 ,
T. Chujo127 , S.U. Chung96 , C. Cicalo106 , L. Ci a elli12 ,28 , F. Cindolo105 , J. Cleymans89 ,
F. Colama ia33 , D. Colella33 , A. Collu25 , M. Colocci28 , G. Conesa Balbas e71 , Z. Conesa del
Valle51 , M.E. Conno s136 , J.G. Con e as11 ,40 , T.M. Co mie 84 , Y. Co ales Mo ales27 ,
I. Co ´es Maldonado2, P. Co ese32 , M.R. Cosen ino119 , F. Cos a36 , P. C oche 70 , R. C uz
Albino11 , E. Cuau le63 , L. Cunquei o36 , T. Dahms92 ,37 , A. Dainese108 , A. Danu62 ,
D. Das101 , I. Das51 ,101 , S. Das4, A. Dash120 , S. Dash48 , S. De131 ,119 , A. De Ca o31 ,12 , G. de
Ca aldo104 , J. de Cu eland43 , A. De Falco25 , D. De G u ola12 ,31 , N. De Ma co111 , S. De
Pasquale31 , A. Delo 77 , E. D´enes135 , G. D’E asmo33 , D. Di Ba i33 , A. Di Mau o36 , P. Di
Nezza72 , M.A. Diaz Co che o10 , T. Die el89 , P. Dillensege 53 , R. Di i`a36 , Ø. Dju sland18 ,
A. Dob in57 ,81 , T. Dob owolski77 ,i, D. Domenicis Gimenez119 , B. D¨onigus53 , O. Do dic22 ,
A.K. Dubey131 , A. Dubla57 , L. Duc oux129 , P. Dupieux70 , R.J. Ehle s136 , D. Elia104 ,
H. Engel52 , B. E azmus113 ,36 , D. Eschweile 43 , B. Espagnon51 , M. Es ienne113 , S. Esumi127 ,
D. E ans102 , S. E dokimo 112 , G. Eyyubo a40 , L. Fabbie i37 ,92 , D. Fab is108 , J. Fai e71 ,
A. Fan oni72 , M. Fasel74 , L. Feldkamp54 , D. Felea62 , A. Feliciello111 , G. Feo ilo 130 ,
J. Fe encei83 , A. Fe n´andez T´ellez2, E.G. Fe ei o17 , A. Fe e i27 , A. Fes an i30 , J. Figiel116 ,
M.A.S. Figue edo123 , S. Filchagin99 , D. Finogee 56 , F.M. Fionda104 , E.M. Fio e33 ,
M.G. Fleck93 , M. Flo is36 , S. Foe sch65 , P. Foka97 , S. Fokin100 , E. F agiacomo110 ,
– 39 –