EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH (CERN)
CERN-PH-EP/2011-016
2011/03/08
CMS-SUS-10-007
Sea ch o Physics Beyond he S anda d Model in
Opposi e-sign Dilep on E en s in pp Collisions a
√s=7 TeV
The CMS Collabo a ion∗
Abs ac
A sea ch is p esen ed o physics beyond he s anda d model (SM) in inal s a es wi h
opposi e-sign isola ed lep on pai s accompanied by had onic je s and missing ans-
e se ene gy. The sea ch is pe o med using LHC da a eco ded wi h he CMS de ec-
o , co esponding o an in eg a ed luminosi y o 34 pb−1. No e idence o an e en
yield beyond SM expec a ions is ound. An uppe limi on he non-SM con ibu ion o
he signal egion is deduced om he esul s. This limi is in e p e ed in he con ex o
he cons ained minimal supe symme ic model. Addi ional in o ma ion is p o ided
o allow es ing he exclusion o speci ic models o physics beyond he SM.
Submi ed o he Jou nal o High Ene gy Physics
∗See Appendix A o he lis o collabo a ion membe s
a Xi :1103.1348 1 [hep-ex] 7 Ma 2011
1
1 In oduc ion
In his pape we desc ibe a sea ch o physics beyond he s anda d model (BSM) in a sample
o p o on-p o on collisions a a cen e-o -mass ene gy o 7 TeV. The da a sample was collec ed
wi h he Compac Muon Solenoid (CMS) de ec o [1] a he La ge Had on Collide (LHC) be-
ween Ma ch and No embe o 2010 and co esponds o an in eg a ed luminosi y o 34 pb−1.
The BSM signa u e in his sea ch is mo i a ed by h ee gene al conside a ions. Fi s , new pa i-
cles p edic ed by BSM physics scena ios a e expec ed o be hea y, since hey ha e so a eluded
de ec ion. Second, BSM physics signals wi h high enough c oss sec ions o be obse ed in ou
cu en da ase a e expec ed o be p oduced s ongly, esul ing in signi ican had onic ac i i y.
Thi d, as ophysical e idence o da k ma e sugges s [2, 3] ha he mass o weakly-in e ac ing
massi e pa icles is o he o de o he elec oweak symme y b eaking scale. Such pa icles, i
p oduced in pp collisions, could escape de ec ion and gi e ise o an appa en imbalance in he
e en ans e se ene gy. We he e o e ocus on he egion o high missing ans e se ene gy
(Emiss
T). An example o a speci ic BSM scena io is p o ided by R-pa i y conse ing supe sym-
me ic (SUSY) models in which new, hea y pa icles a e pai -p oduced and subsequen ly un-
de go cascade decays, p oducing had onic je s and lep ons [4–10]. These cascade decays may
e mina e in he p oduc ion o weakly-in e ac ing massi e pa icles, esul ing in la ge Emiss
T.
The esul s epo ed in his pape a e pa o a b oad p og am o BSM sea ches in e en s wi h
je s and Emiss
T, cha ac e ized by he numbe and ype o lep ons in he inal s a e. He e we
desc ibe a sea ch o e en s con aining opposi e-sign isola ed lep on pai s (e+e−, e±µ∓,µ+µ−)
in addi ion o he je s and Emiss
T. Resul s om a complemen a y sea ch wi h no elec ons o
muons in he inal s a e ha e al eady been epo ed in Re . [11].
Ou analysis s a egy is as ollows. In o de o selec dilep on e en s, we use high-pTlep on
igge s and a p eselec ion based on ha o he c oss sec ion measu emen in he dilep on
channel [12]. Good ag eemen is ound be ween his da a sample and p edic ions om SM
Mon e Ca lo (MC) simula ions in e ms o he e en yields and shapes o a ious kinema ic
dis ibu ions. Because BSM physics is expec ed o ha e la ge had onic ac i i y and Emiss
Tas dis-
cussed abo e, we de ine a signal egion wi h equi emen s on hese quan i ies o selec abou
1% o dilep on e en s, as p edic ed by MC. The obse ed e en yield in he signal egion is
compa ed wi h he p edic ions om wo independen backg ound es ima ion echniques based
on da a con ol samples, as well as wi h SM and BSM MC expec a ions. Finally, he obus ness
o he esul is con i med by an independen analysis based on had onic ac i i y igge s, di -
e en “physics objec ” econs uc ion, and a complemen a y backg ound es ima ion me hod.
No speci ic BSM physics scena io, e.g. a pa icula SUSY model, has been used o op imize
he sea ch. In o de o illus a e he sensi i i y o he sea ch, a simpli ied and p ac ical model
o SUSY b eaking, he cons ained minimal supe symme ic ex ension o he s anda d model
(CMSSM) [13, 14], is used. The CMSSM is desc ibed by i e pa ame e s: he uni e sal scala
and gaugino mass pa ame e s (m0and m1/2, espec i ely), he uni e sal ilinea so SUSY
b eaking pa ame e A0, he a io o he acuum expec a ion alues o he wo Higgs double s
( an β), and he sign o he Higgs mixing pa ame e µ. Th oughou he pape , wo CMSSM
pa ame e se s, e e ed o as LM0 and LM1 [15], a e used o illus a e possible CMSSM yields.
The pa ame e alues de ining LM0 (LM1) a e m0=200 (60)GeV/c2,m1/2 =160 (250)GeV/c2,
A0=−400 (0)GeV; bo h LM0 and LM1 ha e an β=10 and µ>0. These wo scena ios a e
beyond he exclusion each o p e ious sea ches pe o med a he Te a on and LEP. They we e
ecen ly excluded by a sea ch pe o med a CMS in e en s wi h je s and Emiss
T[11] based on he
same da a sample used o his sea ch. In his analysis, he LM0 and LM1 scena ios se e as
benchma ks which may be used o allow compa ison o he sensi i i y wi h o he analyses.
23 E en Selec ion
2 CMS De ec o
The cen al ea u e o he CMS appa a us is a supe conduc ing solenoid, 13 m in leng h and
6 m in diame e , which p o ides an axial magne ic ield o 3.8 T. Wi hin he ield olume a e
se e al pa icle de ec ion sys ems. Cha ged pa icle ajec o ies a e measu ed by silicon pixel
and silicon s ip acke s, co e ing 0 ≤φ≤2πin azimu h and |η|<2.5 in pseudo apid-
i y, de ined as η=−log[ an θ/2], whe e θis he pola angle o he ajec o y o he pa icle
wi h espec o he coun e clockwise p o on beam di ec ion. A c ys al elec omagne ic calo i-
me e and a b ass/scin illa o had onic calo ime e su ound he acking olume, p o iding
ene gy measu emen s o elec ons and had onic je s. Muons a e iden i ied and measu ed in
gas-ioniza ion de ec o s embedded in he s eel e u n yoke ou side he solenoid. The de ec o
is nea ly he me ic, allowing ene gy balance measu emen s in he plane ans e se o he beam
di ec ion. A wo- ie igge sys em selec s he mos in e es ing pp collision e en s o use in
physics analysis. A mo e de ailed desc ip ion o he CMS de ec o can be ound elsewhe e [1].
3 E en Selec ion
Samples o MC e en s a e used o guide he design o he analysis. These e en s a e gene a ed
using ei he he PYTHIA 6.4.22 [16] o MADGRAPH 4.4.12 [17] e en gene a o s. They a e hen
simula ed using a GEANT4-based model [18] o he CMS de ec o , and inally econs uc ed
and analyzed using he same so wa e as is used o p ocess collision da a.
We apply a p eselec ion based on ha o he c oss sec ion measu emen in he dilep on chan-
nel [12]. E en s wi h wo opposi e-sign, isola ed lep ons (e+e−, e±µ∓, o µ+µ−) a e selec ed.
A leas one o he lep ons mus ha e pT>20 GeV/cand bo h mus ha e pT>10 GeV/c, and
he elec ons (muons) mus ha e |η|<2.5 (|η|<2.4). In e en s wi h mo e han wo such lep-
ons, he wo lep ons wi h he highes pTa e selec ed. E en s wi h an e+e−o µ+µ−pai wi h
in a ian mass be ween 76 GeV/c2and 106 GeV/c2o below 10 GeV/c2a e emo ed, in o de o
supp ess D ell–Yan (DY) Z/γ∗→`` e en s, as well as low mass dilep on esonances.
E en s a e equi ed o pass a leas one o a se o single-lep on o double-lep on igge s. The
e iciency o e en s con aining wo lep ons passing he analysis selec ion o pass a leas one
o hese igge s is e y high, in excess o 99% o dilep on ¯
e en s.
Because lep ons p oduced in he decays o low-mass pa icles, such as had ons con aining b
and c qua ks, a e nea ly always inside je s, hey can be supp essed by equi ing he lep ons o
be isola ed in space om o he pa icles ha ca y a subs an ial amoun o ans e se momen-
um. The de ails o he lep on isola ion measu emen a e gi en in Re . [12]. In b ie , a cone is
cons uc ed o size ∆R≡p(∆η)2+ (∆φ)2=0.3 a ound he lep on momen um di ec ion. The
lep on ela i e isola ion is hen quan i ied by summing he ans e se ene gy (as measu ed in
he calo ime e s) and he ans e se momen um (as measu ed in he silicon acke ) o all ob-
jec s wi hin his cone, excluding he lep on, and di iding by he lep on ans e se momen um.
The esul ing quan i y is equi ed o be less han 0.15, ejec ing he la ge backg ound a ising
om QCD p oduc ion o je s.
We equi e he p esence o a leas wo je s wi h pT>30 GeV/cand |η|<2.5, sepa a ed by
∆R>0.4 om lep ons passing he analysis selec ion wi h pT>10 GeV/c. The an i-kTclus e -
ing algo i hm [19] wi h ∆R=0.5 is used o je clus e ing. Je s a e econs uc ed using calo -
ime e in o ma ion and hei ene gies a e co ec ed using econs uc ed acks [20]. The e en
is equi ed o sa is y HT>100 GeV, whe e HTis de ined as he scala sum o he ans e se
ene gies o he selec ed je s. In addi ion, he Emiss
Tin he e en is equi ed o exceed 50 GeV.
3
Se e al echniques a e used in CMS o calcula ing Emiss
T[21]. He e, he aw Emiss
T, calcula ed
om calo ime e signals in he ange |η|<5.0, is co ec ed by aking in o accoun he con ibu-
ions om minimally in e ac ing muons. The Emiss
Tis u he co ec ed on a ack-by- ack basis
o he expec ed esponse o he calo ime e de i ed om simula ion, esul ing in an imp o ed
Emiss
T esolu ion.
The da a yields and co esponding MC p edic ions a e his e en p eselec ion a e gi en in
Table 1. The MC yields a e no malized o 34 pb−1using nex - o-leading o de (NLO) c oss
sec ions. As expec ed, he MC p edic s ha he sample passing he p eselec ion is domina ed
by dilep on . The da a yield is in good ag eemen wi h he p edic ion. We also quo e he
yields o he LM0 and LM1 benchma k scena ios.
Table 1: Da a yields and MC p edic ions a e p eselec ion, using he quo ed NLO p oduc ion
c oss sec ions σ. The →`+`−co esponds o dilep on , including →W→τ→`;
→o he includes all o he decay modes. The samples o MC , W±+ je s, and single-
op e en s we e gene a ed wi h MADGRAPH. The D ell–Yan sample (which includes e en s
wi h in a ian masses as low as 10 GeV/c2) was gene a ed using a mix u e o MADGRAPH
and PYTHIA. All o he samples we e gene a ed wi h PYTHIA. The LM0 and LM1 benchma k
scena ios a e de ined in he ex . Unce ain ies a e s a is ical only.
Sample σ(pb) ee µµ eµTo al
→`+`−16.9 14.50 ±0.24 17.52 ±0.26 41.34 ±0.40 73.36 ±0.53
→o he 140.6 0.49 ±0.04 0.21 ±0.03 1.02 ±0.06 1.72 ±0.08
D ell–Yan 18417 1.02 ±0.21 1.16 ±0.22 1.20 ±0.22 3.38 ±0.37
W±+ je s 28049 0.19 ±0.13 0.00 ±0.00 0.09 ±0.09 0.28 ±0.16
W+W−2.9 0.15 ±0.01 0.16 ±0.01 0.37 ±0.02 0.68 ±0.03
W±Z 0.3 0.02 ±0.00 0.02 ±0.00 0.04 ±0.00 0.09 ±0.00
ZZ 4.3 0.01 ±0.00 0.02 ±0.00 0.02 ±0.00 0.05 ±0.00
Single op 33.0 0.46 ±0.02 0.55 ±0.02 1.24 ±0.03 2.25 ±0.04
To al SM MC 16.85 ±0.34 19.63 ±0.34 45.33 ±0.47 81.81 ±0.67
Da a 15 22 45 82
LM0 52.9 10.67 ±0.31 12.63 ±0.34 17.81 ±0.41 41.11 ±0.62
LM1 6.7 2.35 ±0.05 2.83 ±0.06 1.51 ±0.04 6.69 ±0.09
Figu e 1 compa es se e al kinema ic dis ibu ions in da a and SM MC o e en s passing he
p eselec ion. As an illus a ion, we also show he MC dis ibu ions o he LM1 benchma k
poin . We ind ha he SM MC ep oduces he p ope ies o he bulk o dilep on e en s. We
he e o e u n ou a en ion o he ails o he Emiss
Tand HTdis ibu ions o he sample.
To look o possible BSM con ibu ions, we de ine a signal egion ha p ese es abou 1% o
he dilep on e en s, by adding he ollowing wo equi emen s o he p eselec ion desc ibed
abo e:
HT>300 GeV and y>8.5 GeV1/2, (1)
whe e y≡Emiss
T/√HT. The equi emen is on y a he han Emiss
Tbecause he a iables HT
and ya e ound o be almos unco ela ed in dilep on MC, wi h a co ela ion coe icien o
∼5%. This acili a es he use o a backg ound es ima ion me hod based on da a, as discussed
in Sec ion 4.

44 Backg ound Es ima es om Da a
(GeV)
T
H
0 50 100 150 200 250 300 350 400 450 500
E en s
0
5
10
15
20
25
30 CMS
= 7 TeVs a
-1
34 pb
µ/eµµE en s wi h ee/
)
1/2
y (GeV
0 2 4 6 8 10 12 14 16 18 20
E en s
0
5
10
15
20
25
30
35 CMS
= 7 TeVs a
-1
34 pb
µ/eµµE en s wi h ee/
) (GeV)llM(
0 50 100 150 200 250 300
E en s
0
5
10
15
20
25 CMS
= 7 TeVs a
-1
34 pb
µ/eµµE en s wi h ee/
) (GeV/c)ll(
T
p
0 50 100 150 200 250 300
E en s
0
5
10
15
20
25
30 CMS
= 7 TeVs a
-1
34 pb
µ/eµµE en s wi h ee/
da a
-
l
+
l →
o he →
DY
single op
VV
+ je sW
LM1
Figu e 1: Dis ibu ions o ( op le ) scala sum o je ans e se ene gies (HT), ( op igh )
y≡Emiss
T/√HT, (bo om le ) dilep on in a ian mass M(``), and (bo om igh ) dilep on
ans e se momen um pT(``) o SM MC and da a a e p eselec ion. The las bin con ains he
o e low. He e →`+`−co esponds o dilep on , including →W→τ→`; →o he
includes all o he decay modes, and VV indica es he sum o WW, WZ, and ZZ. The MC
dis ibu ions o he LM1 benchma k poin s a e also shown.
The MC p edic s 1.3 SM e en s, domina ed by dilep on , in he signal egion. The expec a ions
o he LM0 and LM1 poin s a e 8.6 and 3.6 e en s, espec i ely.
4 Backg ound Es ima es om Da a
We ha e de eloped wo independen me hods o es ima e om da a he backg ound in he
signal egion. The i s me hod exploi s he ac ha HTand ya e nea ly unco ela ed o he
backg ound. Fou egions (A, B, C, and D) a e de ined in he y s. HTplane, as indica ed in
Figu e 2, whe e egion D is he signal egion de ined in Eq. 1. In he absence o a signal, he
yields in he egions A, B, and C can be used o es ima e he yield in he signal egion D as
ND=NA×NC/NB; his me hod is e e ed o as he “ABCD me hod”.
The expec ed e en yields in he ou egions o he SM MC, as well as he backg ound p edic-
ion NA×NC/NB, a e gi en in Table 2. We obse e good ag eemen be ween he o al SM MC
p edic ed and obse ed yields. A 20% sys ema ic unce ain y is assigned o he p edic ed yield
o he ABCD me hod o ake in o accoun unce ain ies om con ibu ions o backg ounds
o he han dilep on (16%), ini e MC s a is ics in he closu e es (8%), and a ia ion o he
bounda ies be ween he ABCD egions based on he unce ain y in he had onic ene gy scale
(8%).
The second backg ound es ima e, hence o h e e ed o as he dilep on ans e se momen um
(pT(``)) me hod, is based on he idea [22] ha in dilep on e en s he pTdis ibu ions o
he cha ged lep ons and neu inos om W decays a e ela ed, because o he common boos s
5
om he op and W decays. This ela ion is go e ned by he pola iza ion o he W’s, which
is well unde s ood in op decays in he SM [23, 24] and can he e o e be eliably accoun ed
o . We hen use he obse ed pT(``)dis ibu ion o model he pT(νν)dis ibu ion, which
is iden i ied wi h Emiss
T. Thus, we use he numbe o obse ed e en s wi h HT>300 GeV and
pT(``)/√HT>8.5 GeV1/2 o p edic he numbe o backg ound e en s wi h HT>300 GeV and
y=Emiss
T/√HT>8.5 GeV1/2. In p ac ice, wo co ec ions mus be applied o his p edic ion,
as desc ibed below.
The i s co ec ion accoun s o he Emiss
T>50 GeV equi emen in he p eselec ion, which is
needed o educe he DY backg ound. We escale he p edic ion by a ac o equal o he in e se
o he ac ion o e en s passing he p eselec ion which also sa is y he equi emen pT(``)>
50 GeV/c. This co ec ion ac o is de e mined om MC and is K50 =1.5. The second co ec ion
(KC) is associa ed wi h he known pola iza ion o he W, which in oduces a di e ence be ween
he pT(``)and pT(νν)dis ibu ions. The co ec ion KCalso akes in o accoun de ec o e ec s
such as he had onic ene gy scale and esolu ion which a ec he Emiss
Tbu no pT(``). The
o al co ec ion ac o is K50 ×KC=2.1 ±0.6, whe e he unce ain y is domina ed by he 5%
unce ain y in he had onic ene gy scale [25].
All backg ound es ima ion me hods based on da a a e in p inciple subjec o signal con amina-
ion in he con ol egions, which ends o dec ease he signi icance o a signal which may be
p esen in he da a by inc easing he backg ound p edic ion. In gene al, i is di icul o quan-
i y hese e ec s because we do no know wha signal may be p esen in he da a. Ha ing wo
independen me hods (in addi ion o expec a ions om MC) adds edundancy because signal
con amina ion can ha e di e en e ec s in he di e en con ol egions o he wo me hods.
Fo example, in he ex eme case o a BSM signal wi h iden ical dis ibu ions o pT(``)and
Emiss
T, an excess o e en s migh be seen in he ABCD me hod bu no in he pT(``)me hod.
Backg ounds in which one o bo h lep ons do no o igina e om elec oweak decays (non-W/Z
lep ons) a e assessed using he me hod o Re . [12]. A non-W/Z lep on is a lep on candida e
o igina ing om wi hin a je , such as a lep on om semilep onic b o c decays, a muon decay-
in- ligh , a pion misiden i ied as an elec on, o an uniden i ied pho on con e sion. Es ima es
o he con ibu ions o he signal egion om pu e mul ije QCD, wi h wo non-W/Z lep ons,
and in W +je s, wi h one non-W/Z lep on in addi ion o he lep on om he decay o he W, a e
de i ed sepa a ely. We ind 0.00+0.04
−0.00 and 0.0+0.4
−0.0 o he mul ije QCD and W+je s con ibu ions
espec i ely, and hus conside hese backg ounds o be negligible.
Backg ounds om DY and om p ocesses wi h wo ec o bosons and single op a e negligible
compa ed o dilep on .
5 Resul s
We ind one e en in he signal egion D. The e en is in he eµchannel and con ains 3 je s. The
SM MC expec a ion is 1.3 e en s.
Table 2 summa izes he e en yields ob ained o each o he ou ABCD egions in he da a
and in he MC samples. The p edic ion o he ABCD me hod is gi en by NA×NC/NB=
1.3 ±0.8 (s a .)±0.3 (sys .)e en s. The da a, oge he wi h SM expec a ions, a e p esen ed in
Figu e 2.
The ABCD p edic ion is hen compa ed wi h ha o he pT(``)me hod. We ind 1 e en passing
he equi emen s HT>300 GeV and pT(``)/√HT>8.5 GeV1/2. This leads o a p edic ed
backg ound o 2.1 ±2.1 (s a .)±0.6 (sys .)a e applying he co ec ion ac o K50 ×KC=
66 Accep ance and E iciency Sys ema ic Unce ain ies
(GeV)
T
H
0 200 400 600 800 1000 1200 1400
)
1/2
y (GeV
0
5
10
15
20
25
30
SM MC
Da a
B
A
C
D
CMS
= 7 TeVs a
-1
34.0 pb
µ/eµµE en s wi h ee/
Figu e 2: Dis ibu ions o y s. HT o SM MC (2-dimensional his og am) and da a (sca e plo ).
He e ou choice o he ABCD egions is also shown.
2.1 ±0.6, as shown in Figu e 3 (le ).
As a alida ion o he pT(``)me hod in a egion wi h highe s a is ics, we also apply he pT(``)
me hod in con ol egion A by es ic ing HT o be in he ange 125–300 GeV. He e he p e-
dic ion is 9.0 ±6.0 (s a .)backg ound e en s, in good ag eemen wi h he obse ed yield o 12
e en s, as shown in Figu e 3 ( igh ).
In summa y, o he signal egion de ined as HT>300 GeV and y>8.5 GeV1/2: we obse e
one e en in he da a, SM MC p edic s 1.3 e en s, he ABCD me hod p edic s 1.3 ±0.8 (s a .)±
0.3 (sys .)e en s, and he pT(``)me hod p edic s 2.1 ±2.1 (s a .)±0.6 (sys .)e en s.
All h ee backg ound p edic ions a e consis en wi hin hei unce ain ies. We hus ake as
ou bes es ima e o he SM yield in he signal egion he e o -weigh ed a e age o he wo
backg ound es ima es based on da a and ind a numbe o p edic ed backg ound e en s NBG =
1.4 ±0.8, in good ag eemen wi h he obse ed signal yield. We he e o e conclude ha no
e idence o a non-SM con ibu ion o he signal egion is obse ed.
6 Accep ance and E iciency Sys ema ic Unce ain ies
The accep ance and e iciency, as well as he sys ema ic unce ain ies in hese quan i ies, de-
pend on he signal model. Fo some o he indi idual unce ain ies, i is easonable o quo e
alues based on SM con ol samples wi h kinema ic p ope ies simila o he SUSY benchma k
models. Fo o he s ha depend s ongly on he kinema ic p ope ies o he e en , he sys em-
a ic unce ain ies mus be quo ed model by model.
The sys ema ic unce ain y in he lep on accep ance consis s o wo pa s: he igge e iciency
unce ain y and he iden i ica ion and isola ion unce ain y. The igge e iciency o wo lep-
ons o pT>10 GeV/c, wi h one lep on o pT>20 GeV/cis close o 100%. We es ima e he e i-
ciency unce ain y o be a ew pe cen , mos ly in he low pT egion, using samples o Z →``.
7
Table 2: Da a yields in he ou egions o Figu e 2, as well as he p edic ed yield in egion
D gi en by NA×NC/NB. The SM and BSM MC expec a ions a e also shown. The quo ed
unce ain ies a e s a is ical only.
Sample NANBNCNDNA×NC/NB
→`+`−8.44 ±0.18 32.83 ±0.35 4.78 ±0.14 1.07 ±0.06 1.23 ±0.05
→o he 0.12 ±0.02 0.78 ±0.05 0.16 ±0.02 0.02 ±0.01 0.02 ±0.01
D ell–Yan 0.17 ±0.08 1.18 ±0.22 0.04 ±0.04 0.12 ±0.07 0.01 ±0.01
W±+ je s 0.00 ±0.00 0.09 ±0.09 0.00 ±0.00 0.00 ±0.00 0.00 ±0.00
W+W−0.11 ±0.01 0.29 ±0.02 0.02 ±0.01 0.03 ±0.01 0.01 ±0.00
W±Z0.01 ±0.00 0.04 ±0.00 0.00 ±0.00 0.00 ±0.00 0.00 ±0.00
ZZ 0.01 ±0.00 0.02 ±0.00 0.00 ±0.00 0.00 ±0.00 0.00 ±0.00
Single op 0.29 ±0.01 1.04 ±0.03 0.04 ±0.01 0.01 ±0.00 0.01 ±0.00
To al SM MC 9.14 ±0.20 36.26 ±0.43 5.05 ±0.14 1.27 ±0.10 1.27 ±0.05
Da a 12 37 4 1 1.30 ±0.78
LM0 4.04 ±0.19 4.45 ±0.20 13.92 ±0.36 8.63 ±0.27 12.63 ±0.88
LM1 0.52 ±0.02 0.26 ±0.02 1.64 ±0.04 3.56 ±0.06 3.33 ±0.27
)
1/2
y (GeV
0 2 4 6 8 10 12 14 16 18 20
E en s
-3
10
-2
10
-1
10
1
10
2
10
3
10 MC p edic ed
MC obse ed
da a p edic ed
da a obse ed
µ/eµµE en s wi h ee/
> 300 GeV
T
H
CMS = 7 TeVs,
-1
= 34 pb
in
L
)
1/2
y (GeV
0 2 4 6 8 10 12 14 16 18 20
E en s
-3
10
-2
10
-1
10
1
10
2
10
3
10 MC p edic ed
MC obse ed
da a p edic ed
da a obse ed
µ/eµµE en s wi h ee/
< 300 GeV
T
125 < H
CMS = 7 TeVs,
-1
= 34 pb
in
L
Figu e 3: Dis ibu ions o y(obse ed) and pT(``)/√HTscaled by he co ec ion ac o K50
(p edic ed) o (le ) he signal egion and ( igh ) he con ol egion A, o bo h MC and da a.
The e ical dashed line indica es he sea ch egion de ined by y>8.5 GeV1/2. The de ici a
low yis due o he Emiss
T>50 GeV p eselec ion equi emen .
Fo dilep on , LM0, and LM1, he igge e iciency unce ain ies a e ound o be less han 1%.
We e i y ha he MC ep oduces he lep on iden i ica ion and isola ion e iciencies in da a
using samples o Z →``; he da a and MC e iciencies a e ound o be consis en wi hin 2%.
Ano he signi ican sou ce o sys ema ic unce ain y is associa ed wi h he je and Emiss
Tene gy
scale. The impac o his unce ain y is inal-s a e dependen . Final s a es cha ac e ized by
e y la ge had onic ac i i y and Emiss
Ta e less sensi i e han inal s a es whe e he Emiss
Tand
HTa e ypically close o he minimum equi emen s applied o hese quan i ies. To be mo e
quan i a i e, we ha e used he me hod o Re . [12] o e alua e he sys ema ic unce ain ies in
he accep ance o and o he wo benchma k SUSY poin s using a 5% unce ain y in he
had onic ene gy scale [25]. Fo he unce ain y is 27%; o LM0 and LM1 he unce ain ies
a e 14% and 6%, espec i ely.
The unce ain y in he in eg a ed luminosi y is 11% [26].
14 10 Summa y
[24] A. Cza necki, J. G. Ko ne , and J. H. Piclum, “Helici y ac ions o W bosons om op
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collide obse ables”, Phys. Re . D78 (2008) 013004.
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15
A The CMS Collabo a ion
Ye e an Physics Ins i u e, Ye e an, A menia
S. Cha chyan, V. Khacha yan, A.M. Si unyan, A. Tumasyan
Ins i u ¨u Hochene giephysik de OeAW, Wien, Aus ia
W. Adam, T. Be gaue , M. D agice ic, J. E ¨
o, C. Fabjan, M. F iedl, R. F ¨
uhwi h, V.M. Ghe e,
J. Hamme 1, S. H¨
ansel, M. Hoch, N. H¨
o mann, J. H ubec, M. Jei le , G. Kasieczka,
W. Kiesenho e , M. K amme , D. Liko, I. Mikulec, M. Pe nicka, H. Roh inge , R. Sch¨
o beck,
J. S auss, F. Teischinge , P. Wagne , W. Wal enbe ge , G. Walzel, E. Widl, C.-E. Wulz
Na ional Cen e o Pa icle and High Ene gy Physics, Minsk, Bela us
V. Mossolo , N. Shumeiko, J. Sua ez Gonzalez
Uni e si ei An we pen, An we pen, Belgium
L. Benucci, E.A. De Wol , X. Janssen, T. Maes, L. Mucibello, S. Ochesanu, B. Roland, R. Rougny,
M. Sel aggi, H. Van Hae e mae , P. Van Mechelen, N. Van Remo el
V ije Uni e si ei B ussel, B ussel, Belgium
F. Blekman, S. Blywee , J. D’Hond , O. De oede, R. Gonzalez Sua ez, A. Kaloge opoulos,
J. Maes, M. Maes, W. Van Doninck, P. Van Mulde s, G.P. Van Onsem, I. Villella
Uni e si ´e Lib e de B uxelles, B uxelles, Belgium
O. Cha a , B. Cle baux, G. De Len decke , V. De o, A.P.R. Gay, G.H. Hammad, T. H eus,
P.E. Ma age, L. Thomas, C. Vande Velde, P. Vanlae
Ghen Uni e si y, Ghen , Belgium
V. Adle , S. Cos an ini, M. G unewald, B. Klein, A. Ma ino , J. Mcca in, D. Ryckbosch,
F. Thyssen, M. Ty ga , L. Vanelde en, P. Ve willigen, S. Walsh, N. Zaganidis
Uni e si ´e Ca holique de Lou ain, Lou ain-la-Neu e, Belgium
S. Basegmez, G. B uno, J. Caud on, L. Cea d, E. Co ina Gil, J. De Fa e eau De Jene e ,
C. Delae e, D. Fa a , A. Giammanco, G. G ´
egoi e, J. Holla , V. Lemai e, J. Liao, O. Mili a u,
S. O yn, D. Pagano, A. Pin, K. Pio zkowski, N. Schul
Uni e si ´e de Mons, Mons, Belgium
N. Beliy, T. Caebe gs, E. Daubie
Cen o B asilei o de Pesquisas Fisicas, Rio de Janei o, B azil
G.A. Al es, D. De Jesus Damiao, M.E. Pol, M.H.G. Souza
Uni e sidade do Es ado do Rio de Janei o, Rio de Janei o, B azil
W. Ca alho, E.M. Da Cos a, C. De Oli ei a Ma ins, S. Fonseca De Souza, L. Mundim,
H. Nogima, V. Ogu i, W.L. P ado Da Sil a, A. San o o, S.M. Sil a Do Ama al, A. Sznajde ,
F. To es Da Sil a De A aujo
Ins i u o de Fisica Teo ica, Uni e sidade Es adual Paulis a, Sao Paulo, B azil
F.A. Dias, T.R. Fe nandez Pe ez Tomei, E. M. G ego es2, C. Lagana, F. Ma inho,
P.G. Me cadan e2, S.F. No aes, Sand a S. Padula
Ins i u e o Nuclea Resea ch and Nuclea Ene gy, So ia, Bulga ia
N. Da meno 1, L. Dimi o , V. Genche 1, P. Iaydjie 1, S. Pipe o , M. Rodozo , S. S oyko a,
G. Sul ano , V. Tcholako , R. T ayano , I. Vanko
16 A The CMS Collabo a ion
Uni e si y o So ia, So ia, Bulga ia
A. Dimi o , M. Dyulenda o a, R. Hadjiiska, A. Ka adzhino a, V. Kozhuha o , L. Li o ,
E. Ma ino a, M. Ma ee , B. Pa lo , P. Pe ko
Ins i u e o High Ene gy Physics, Beijing, China
J.G. Bian, G.M. Chen, H.S. Chen, C.H. Jiang, D. Liang, S. Liang, X. Meng, J. Tao, J. Wang,
J. Wang, X. Wang, Z. Wang, H. Xiao, M. Xu, J. Zang, Z. Zhang
S a e Key Lab. o Nucl. Phys. and Tech., Peking Uni e si y, Beijing, China
Y. Ban, S. Guo, Y. Guo, W. Li, Y. Mao, S.J. Qian, H. Teng, L. Zhang, B. Zhu, W. Zou
Uni e sidad de Los Andes, Bogo a, Colombia
A. Cab e a, B. Gomez Mo eno, A.A. Ocampo Rios, A.F. Oso io Oli e os, J.C. Sanab ia
Technical Uni e si y o Spli , Spli , C oa ia
N. Godino ic, D. Lelas, K. Lelas, R. Ples ina3, D. Polic, I. Puljak
Uni e si y o Spli , Spli , C oa ia
Z. An uno ic, M. Dzelalija
Ins i u e Rudje Bosko ic, Zag eb, C oa ia
V. B iglje ic, S. Du ic, K. Kadija, S. Mo o ic
Uni e si y o Cyp us, Nicosia, Cyp us
A. A ikis, M. Galan i, J. Mousa, C. Nicolaou, F. P ochos, P.A. Razis
Cha les Uni e si y, P ague, Czech Republic
M. Finge , M. Finge J .
Academy o Scien i ic Resea ch and Technology o he A ab Republic o Egyp , Egyp ian
Ne wo k o High Ene gy Physics, Cai o, Egyp
A. Awad, S. Khalil4, M.A. Mahmoud5
Na ional Ins i u e o Chemical Physics and Biophysics, Tallinn, Es onia
A. Hek o , M. Kadas ik, M. M¨
un el, M. Raidal, L. Rebane
Depa men o Physics, Uni e si y o Helsinki, Helsinki, Finland
V. Azzolini, P. Ee ola
Helsinki Ins i u e o Physics, Helsinki, Finland
S. Czella , J. H¨
a k¨
onen, V. Ka im¨
aki, R. Kinnunen, M.J. Ko elainen, T. Lamp´
en, K. Lassila-
Pe ini, S. Leh i, T. Lind´
en, P. Luukka, T. M¨
aenp¨
a¨
a, E. Tuominen, J. Tuominiemi, E. Tuo inen,
D. Unga o, L. Wendland
Lappeen an a Uni e si y o Technology, Lappeen an a, Finland
K. Banzuzi, A. Ko pela, T. Tuu a
Labo a oi e d’Annecy-le-Vieux de Physique des Pa icules, IN2P3-CNRS, Annecy-le-Vieux,
F ance
D. Sillou
DSM/IRFU, CEA/Saclay, Gi -su -Y e e, F ance
M. Besancon, S. Choudhu y, M. Deja din, D. Deneg i, B. Fabb o, J.L. Fau e, F. Fe i, S. Ganjou ,
F.X. Gen i , A. Gi e naud, P. G as, G. Hamel de Monchenaul , P. Ja y, E. Locci, J. Malcles,
M. Ma ionneau, L. Millische , J. Rande , A. Rosowsky, I. Sh eybe , M. Ti o , P. Ve ecchia
17
Labo a oi e Lep ince-Ringue , Ecole Poly echnique, IN2P3-CNRS, Palaiseau, F ance
S. Ba ioni, F. Beaude e, L. Benhabib, L. Bianchini, M. Bluj6, C. B ou in, P. Busson, C. Cha lo ,
T. Dahms, L. Dob zynski, S. Elgammal, R. G anie de Cassagnac, M. Haguenaue , P. Min´
e,
C. Mi ono , C. Ochando, P. Paganini, D. Sabes, R. Sale no, Y. Si ois, C. Thiebaux, B. Wyslouch7,
A. Zabi
Ins i u Plu idisciplinai e Hube Cu ien, Uni e si ´e de S asbou g, Uni e si ´e de Hau e
Alsace Mulhouse, CNRS/IN2P3, S asbou g, F ance
J.-L. Ag am8, J. And ea, D. Bloch, D. Bodin, J.-M. B om, M. Ca daci, E.C. Chabe , C. Colla d,
E. Con e8, F. D ouhin8, C. Fe o, J.-C. Fon aine8, D. Gel´
e, U. Goe lach, S. G ede , P. Juillo ,
M. Ka im8, A.-C. Le Bihan, Y. Mikami, P. Van Ho e
Cen e de Calcul de l’Ins i u Na ional de Physique Nucleai e e de Physique des
Pa icules (IN2P3), Villeu banne, F ance
F. Fassi, D. Me cie
Uni e si ´e de Lyon, Uni e si ´e Claude Be na d Lyon 1, CNRS-IN2P3, Ins i u de Physique
Nucl´eai e de Lyon, Villeu banne, F ance
C. Ba y, S. Beauce on, N. Beaupe e, M. Bedjidian, O. Bondu, G. Boudoul, D. Boumediene,
H. B un, N. Chanon, R. Chie ici, D. Con a do, P. Depasse, H. El Mamouni, A. Falkiewicz, J. Fay,
S. Gascon, B. Ille, T. Ku ca, T. Le G and, M. Le huillie , L. Mi abi o, S. Pe ies, V. So dini, S. Tosi,
Y. Tschudi, P. Ve die
E. And onikash ili Ins i u e o Physics, Academy o Science, Tbilisi, Geo gia
L. Meg elidze
Ins i u e o High Ene gy Physics and In o ma iza ion, Tbilisi S a e Uni e si y, Tbilisi,
Geo gia
D. Lomidze
RWTH Aachen Uni e si y, I. Physikalisches Ins i u , Aachen, Ge many
G. Anagnos ou, M. Edelho , L. Feld, N. He acleous, O. Hind ichs, R. Jussen, K. Klein, J. Me z,
N. Moh , A. Os apchuk, A. Pe ieanu, F. Raupach, J. Samme , S. Schael, D. Sp enge , H. Webe ,
M. Webe , B. Wi me
RWTH Aachen Uni e si y, III. Physikalisches Ins i u A, Aachen, Ge many
M. A a, W. Bende , M. E dmann, J. F angenheim, T. Hebbeke , A. Hinzmann, K. Hoep ne ,
C. Ho , T. Klimko ich, D. Klingebiel, P. K euze , D. Lanske†, C. Magass, M. Me schmeye ,
A. Meye , P. Papacz, H. Pie a, H. Rei hle , S.A. Schmi z, L. Sonnenschein, J. S eggemann,
D. Teyssie , M. Tonu i
RWTH Aachen Uni e si y, III. Physikalisches Ins i u B, Aachen, Ge many
M. Bon enackels, M. Da ids, M. Duda, G. Fl¨
ugge, H. Geenen, M. Gi els, W. Haj Ahmad,
D. Heydhausen, T. K ess, Y. Kuessel, A. Linn, A. Nowack, L. Pe challa, O. Poo h, J. Renne eld,
P. Saue land, A. S ahl, M. Thomas, D. To nie , M.H. Zoelle
Deu sches Elek onen-Synch o on, Hambu g, Ge many
M. Aldaya Ma in, W. Beh enho , U. Beh ens, M. Be gholz9, K. Bo as, A. Caki , A. Campbell,
E. Cas o, D. Dammann, G. Ecke lin, D. Ecks ein, A. Flossdo , G. Flucke, A. Geise , J. Hauk,
H. Jung1, M. Kasemann, I. Ka ko 10, P. Ka sas, C. Kleinwo , H. Kluge, A. Knu sson, M. K ¨
ame ,
D. K ¨
ucke , E. Kuzne so a, W. Lange, W. Lohmann9, R. Mankel, M. Ma ien eld, I.-A. Melze -
Pellmann, A.B. Meye , J. Mnich, A. Mussgille , J. Olzem, D. Pi zl, A. Raspe eza, A. Ra al,
M. Rosin, R. Schmid 9, T. Schoe ne -Sadenius, N. Sen, A. Spi idono , M. S ein, J. Tomaszewska,
R. Walsh, C. Wissing
18 A The CMS Collabo a ion
Uni e si y o Hambu g, Hambu g, Ge many
C. Au e mann, V. Blobel, S. Bob o skyi, J. D aege , H. Ende le, U. Gebbe , K. Kaschube,
G. Kaussen, R. Klanne , J. Lange, B. Mu a, S. Naumann-Emme, F. Nowak, N. Pie sch, C. Sande ,
H. Sche le , P. Schlepe , M. Sch ¨
ode , T. Schum, J. Schwand , H. S adie, G. S einb ¨
uck,
J. Thomsen
Ins i u ¨u Expe imen elle Ke nphysik, Ka ls uhe, Ge many
C. Ba h, J. Baue , V. Buege, T. Chwalek, W. De Boe , A. Die lamm, G. Di kes, M. Feind ,
J. G uschke, C. Hacks ein, F. Ha mann, S.M. Heindl, M. Hein ich, H. Held, K.H. Ho mann,
S. Honc, J.R. Koma agi i, T. Kuh , D. Ma schei, S. Muelle , Th. M¨
ulle , M. Niegel, O. Obe s ,
A. Oehle , J. O , T. Pei e , D. Pipa o, G. Quas , K. Rabbe z, F. Ra niko , N. Ra niko a, M. Renz,
C. Saou , A. Scheu e , P. Schie e decke , F.-P. Schilling, M. Schmanau, G. Scho , H.J. Simonis,
F.M. S obe , D. T oendle, J. Wagne -Kuh , T. Weile , M. Zeise, V. Zhuko 10, E.B. Zieba h
Ins i u e o Nuclea Physics ”Demok i os”, Aghia Pa aske i, G eece
G. Daskalakis, T. Ge alis, K. Ka a asoulis, S. Kesisoglou, A. Ky iakis, D. Loukas, I. Manolakos,
A. Ma kou, C. Ma kou, C. Ma omma is, E. N oma i, E. Pe akou
Uni e si y o A hens, A hens, G eece
L. Gouskos, T.J. Me zimekis, A. Panagio ou, E. S ilia is
Uni e si y o Io´annina, Io´annina, G eece
I. E angelou, C. Foudas, P. Kokkas, N. Man hos, I. Papadopoulos, V. Pa as, F.A. T ian is
KFKI Resea ch Ins i u e o Pa icle and Nuclea Physics, Budapes , Hunga y
A. A anyi, G. Bencze, L. Boldizsa , C. Hajdu1, P. Hidas, D. Ho a h11, A. Kapusi, K. K ajcza 12,
B. Radics, F. Sikle , G.I. Ve es12, G. Vesz e gombi12
Ins i u e o Nuclea Resea ch ATOMKI, Deb ecen, Hunga y
N. Beni, J. Molna , J. Palinkas, Z. Szillasi, V. Veszp emi
Uni e si y o Deb ecen, Deb ecen, Hunga y
P. Raics, Z.L. T ocsanyi, B. Uj a i
Panjab Uni e si y, Chandiga h, India
S. Bansal, S.B. Be i, V. Bha naga , N. Dhing a, R. Gup a, M. Jindal, M. Kau , J.M. Kohli,
M.Z. Meh a, N. Nishu, L.K. Saini, A. Sha ma, A.P. Singh, J.B. Singh, S.P. Singh
Uni e si y o Delhi, Delhi, India
S. Ahuja, S. Bha acha ya, B.C. Choudha y, P. Gup a, S. Jain, S. Jain, A. Kuma , K. Ranjan,
R.K. Shi pu i
Bhabha A omic Resea ch Cen e, Mumbai, India
R.K. Choudhu y, D. Du a, S. Kailas, V. Kuma , A.K. Mohan y1, L.M. Pan , P. Shukla
Ta a Ins i u e o Fundamen al Resea ch - EHEP, Mumbai, India
T. Aziz, M. Guchai 13, A. Gu u, M. Mai y14, D. Majumde , G. Majumde , K. Mazumda ,
G.B. Mohan y, A. Saha, K. Sudhaka , N. Wick amage
Ta a Ins i u e o Fundamen al Resea ch - HECR, Mumbai, India
S. Bane jee, S. Dugad, N.K. Mondal
Ins i u e o Resea ch and Fundamen al Sciences (IPM), Teh an, I an
H. A aei, H. Bakhshiansohi, S.M. E esami, A. Fahim, M. Hashemi, A. Ja a i, M. Khakzad,
A. Mohammadi, M. Mohammadi Naja abadi, S. Pak ina Mehdiabadi, B. Sa a zadeh,
M. Zeinali
19
INFN Sezione di Ba i a, Uni e si `a di Ba i b, Poli ecnico di Ba i c, Ba i, I aly
M. Abb esciaa,b, L. Ba bonea,b, C. Calab iaa,b, A. Colaleoa, D. C eanzaa,c, N. De Filippisa,c,1,
M. De Palmaa,b, L. Fio ea, G. Iasellia,c, L. Lusi oa,b, G. Maggia,c, M. Maggia, N. Mannaa,b,
B. Ma angellia,b, S. Mya,c, S. Nuzzoa,b, N. Paci icoa,b, G.A. Pie oa, A. Pompilia,b, G. Pugliesea,c,
F. Romanoa,c, G. Rosellia,b, G. Sel aggia,b, L. Sil es isa, R. T en aduea, S. Tuppu ia,b, G. Zi oa
INFN Sezione di Bologna a, Uni e si `a di Bologna b, Bologna, I aly
G. Abbiendia, A.C. Ben enu ia, D. Bonaco sia, S. B aiban -Giacomellia,b, L. B igliado ia,
P. Capiluppia,b, A. Cas oa,b, F.R. Ca alloa, M. Cu iania,b, G.M. Dalla allea, F. Fabb ia,
A. Fan ania,b, D. Fasanellaa, P. Giacomellia, M. Giun aa, C. G andia, S. Ma cellinia, G. Mase i,
M. Meneghellia,b, A. Mon ana ia, F.L. Na a iaa,b, F. Odo icia, A. Pe o aa, A.M. Rossia,b,
T. Ro ellia,b, G. Si olia,b, R. T a aglinia,b
INFN Sezione di Ca ania a, Uni e si `a di Ca ania b, Ca ania, I aly
S. Albe goa,b, G. Cappelloa,b, M. Chio bolia,b,1, S. Cos aa,b, A. T icomia,b, C. Tu ea
INFN Sezione di Fi enze a, Uni e si `a di Fi enze b, Fi enze, I aly
G. Ba baglia, V. Ciullia,b, C. Ci ininia, R. D’Alessand oa,b, E. Foca dia,b, S. F osalia,b, E. Galloa,
S. Gonzia,b, P. Lenzia,b, M. Meschinia, S. Paole ia, G. Sguazzonia, A. T opianoa,1
INFN Labo a o i Nazionali di F asca i, F asca i, I aly
L. Benussi, S. Bianco, S. Cola anceschi15, F. Fabb i, D. Piccolo
INFN Sezione di Geno a, Geno a, I aly
P. Fabb ica o e, R. Musenich
INFN Sezione di Milano-Biccoca a, Uni e si `a di Milano-Bicocca b, Milano, I aly
A. Benagliaa,b, F. De Guioa,b,1, L. Di Ma eoa,b, A. Ghezzia,b, M. Malbe ia,b, S. Mal ezzia,
A. Ma ellia,b, A. Massi onia,b, D. Menascea, L. Mo onia, M. Paganonia,b, D. Ped inia,
S. Ragazzia,b, N. Redaellia, S. Salaa, T. Taba elli de Fa isa,b, V. Tancinia,b
INFN Sezione di Napoli a, Uni e si `a di Napoli ”Fede ico II” b, Napoli, I aly
S. Buon empoa, C.A. Ca illo Mon oyaa,1, N. Ca alloa,16, A. Cimminoa,b, A. De Cosaa,b,
F. Fabozzia,16, A.O.M. Io ioa, L. Lis aa, M. Me olaa,b, P. Nolia,b, P. Paoluccia
INFN Sezione di Pado a a, Uni e si `a di Pado a b, Uni e si `a di T en o (T en o) c, Pado a,
I aly
P. Azzia, N. Bacche aa, P. Bellana,b, D. Biselloa,b, A. B ancaa, R. Ca lina,b, P. Checchiaa,
M. De Ma iaa,b, T. Do igoa, U. Dossellia, F. Fanzagoa, F. Gaspa inia,b, U. Gaspa inia,b,
S. Lacap a aa,17, I. Lazzizze aa,c, M. Ma gonia,b, M. Mazzuca oa, A.T. Meneguzzoa,b,
M. Nespoloa,1, L. Pe ozzia,1, N. Pozzobona,b, P. Ronchesea,b, F. Simone oa,b, E. To assaa,
M. Tosia,b, S. Vaninia,b, P. Zo oa,b, G. Zume lea,b
INFN Sezione di Pa ia a, Uni e si `a di Pa ia b, Pa ia, I aly
U. Be zanoa, S.P. Ra ia,b, C. Ricca dia,b, P. To ea,b, P. Vi uloa,b
INFN Sezione di Pe ugia a, Uni e si `a di Pe ugia b, Pe ugia, I aly
M. Biasinia,b, G.M. Bileia, B. Capone ia,b, L. Fan`
oa,b, P. La icciaa,b, A. Luca onia,b,1,
G. Man o ania,b, M. Menichellia, A. Nappia,b, F. Romeoa,b, A. San occhiaa,b, S. Ta onia,b,1,
M. Valda aa,b, R. Volpea,b
INFN Sezione di Pisa a, Uni e si `a di Pisa b, Scuola No male Supe io e di Pisa c, Pisa, I aly
P. Azzu ia,c, G. Bagliesia, J. Be na dinia,b, T. Boccalia,1, G. B occoloa,c, R. Cas aldia,
R.T. D’Agnoloa,c, R. Dell’O soa, F. Fio ia,b, L. Fo`
aa,c, A. Giassia, A. K aana, F. Ligabuea,c,

20 A The CMS Collabo a ion
T. Lom adzea, L. Ma inia,18, A. Messineoa,b, F. Pallaa, F. Palmona ia, G. Segne ia, A.T. Se bana,
P. Spagnoloa, R. Tenchinia, G. Tonellia,b,1, A. Ven u ia,1, P.G. Ve dinia
INFN Sezione di Roma a, Uni e si `a di Roma ”La Sapienza” b, Roma, I aly
L. Ba onea,b, F. Ca alla ia, D. Del Rea,b, E. Di Ma coa,b, M. Diemoza, D. F ancia,b, M. G assia,1,
E. Longoa,b, S. Nou bakhsha, G. O gan inia,b, A. Palmaa,b, F. Pandol ia,b,1, R. Pa ama ia,
S. Raha loua,b
INFN Sezione di To ino a, Uni e si `a di To ino b, Uni e si `a del Piemon e O ien ale (No-
a a) c, To ino, I aly
N. Amapanea,b, R. A cidiaconoa,c, S. A gi oa,b, M. A neodoa,c, C. Biinoa, C. Bo aa,b,1,
N. Ca igliaa, R. Cas elloa,b, M. Cos aa,b, N. Dema iaa, A. G azianoa,b,1, C. Ma io ia,
M. Ma onea,b, S. Masellia, E. Miglio ea,b, G. Milaa,b, V. Monacoa,b, M. Musicha,b,
M.M. Obe inoa,c, N. Pas onea, M. Pelliccionia,b, A. Rome oa,b, M. Ruspaa,c, R. Sacchia,b,
V. Solaa,b, A. Solanoa,b, A. S aianoa, D. T ocinoa,b, A. Vilela Pe ei aa,b
INFN Sezione di T ies e a, Uni e si `a di T ies e b, T ies e, I aly
S. Bel o ea, F. Cossu ia, G. Della Riccaa,b, B. Gobboa, D. Mon aninoa,b, A. Penzoa
Kangwon Na ional Uni e si y, Chunchon, Ko ea
S.G. Heo, S.K. Nam
Kyungpook Na ional Uni e si y, Daegu, Ko ea
S. Chang, J. Chung, D.H. Kim, G.N. Kim, J.E. Kim, D.J. Kong, H. Pa k, S.R. Ro, D. Son, D.C. Son
Chonnam Na ional Uni e si y, Ins i u e o Uni e se and Elemen a y Pa icles, Kwangju,
Ko ea
Ze o Kim, J.Y. Kim, S. Song
Ko ea Uni e si y, Seoul, Ko ea
S. Choi, B. Hong, M.S. Jeong, M. Jo, H. Kim, J.H. Kim, T.J. Kim, K.S. Lee, D.H. Moon, S.K. Pa k,
H.B. Rhee, E. Seo, S. Shin, K.S. Sim
Uni e si y o Seoul, Seoul, Ko ea
M. Choi, S. Kang, H. Kim, C. Pa k, I.C. Pa k, S. Pa k, G. Ryu
Sungkyunkwan Uni e si y, Suwon, Ko ea
Y. Choi, Y.K. Choi, J. Goh, M.S. Kim, E. Kwon, J. Lee, S. Lee, H. Seo, I. Yu
Vilnius Uni e si y, Vilnius, Li huania
M.J. Bilinskas, I. G igelionis, M. Janulis, D. Ma isiu e, P. Pe o , T. Sabonis
Cen o de In es igacion y de Es udios A anzados del IPN, Mexico Ci y, Mexico
H. Cas illa-Valdez, E. De La C uz-Bu elo, R. Lopez-Fe nandez, A. S´
anchez-He n´
andez,
L.M. Villaseno -Cendejas
Uni e sidad Ibe oame icana, Mexico Ci y, Mexico
S. Ca illo Mo eno, F. Vazquez Valencia
Beneme i a Uni e sidad Au onoma de Puebla, Puebla, Mexico
H.A. Salaza Iba guen
Uni e sidad Au ´onoma de San Luis Po os´ı, San Luis Po os´ı, Mexico
E. Casimi o Lina es, A. Mo elos Pineda, M.A. Reyes-San os
Uni e si y o Auckland, Auckland, New Zealand
D. K o check, J. Tam
21
Uni e si y o Can e bu y, Ch is chu ch, New Zealand
P.H. Bu le , R. Doesbu g, H. Sil e wood
Na ional Cen e o Physics, Quaid-I-Azam Uni e si y, Islamabad, Pakis an
M. Ahmad, I. Ahmed, M.I. Asgha , H.R. Hoo ani, W.A. Khan, T. Khu shid, S. Qazi
Ins i u e o Expe imen al Physics, Facul y o Physics, Uni e si y o Wa saw, Wa saw, Poland
M. Cwiok, W. Dominik, K. Do oba, A. Kalinowski, M. Konecki, J. K olikowski
Sol an Ins i u e o Nuclea S udies, Wa saw, Poland
T. F ueboes, R. Gokieli, M. G´
o ski, M. Kazana, K. Naw ocki, K. Romanowska-Rybinska,
M. Szlepe , G. W ochna, P. Zalewski
Labo a ´o io de Ins umen a¸c˜ao e F´ısica Expe imen al de Pa ´ıculas, Lisboa, Po ugal
N. Almeida, P. Ba gassa, A. Da id, P. Faccioli, P.G. Fe ei a Pa acho, M. Gallina o, P. Musella,
A. Nayak, J. Seixas, J. Va ela
Join Ins i u e o Nuclea Resea ch, Dubna, Russia
S. A anasie , I. Belo elo , P. Bunin, I. Golu in, A. Kamene , V. Ka ja in, G. Kozlo , A. Lane ,
P. Moisenz, V. Palichik, V. Pe elygin, S. Shma o , V. Smi no , A. Volodko, A. Za ubin
Pe e sbu g Nuclea Physics Ins i u e, Ga china (S Pe e sbu g), Russia
V. Golo so , Y. I ano , V. Kim, P. Le chenko, V. Mu zin, V. O eshkin, I. Smi no , V. Sulimo ,
L. U a o , S. Va ilo , A. Vo obye , A. Vo obye
Ins i u e o Nuclea Resea ch, Moscow, Russia
Yu. And ee , A. De mene , S. Gninenko, N. Golube , M. Ki sano , N. K asniko , V. Ma ee ,
A. Pashenko , A. To opin, S. T oi sky
Ins i u e o Theo e ical and Expe imen al Physics, Moscow, Russia
V. Epsh eyn, V. Ga ilo , V. Ka ano †, M. Kosso 1, A. K okho in, N. Lychko skaya, V. Popo ,
G. Sa ono , S. Semeno , V. S olin, E. Vlaso , A. Zhokin
Moscow S a e Uni e si y, Moscow, Russia
E. Boos, M. Dubinin19, L. Dudko, A. G ibushin, V. Klyukhin, O. Kodolo a, A. Ma kina,
S. Ob az so , M. Pe ilo , S. Pe ushanko, L. Sa yche a, V. Sa in
P.N. Lebede Physical Ins i u e, Moscow, Russia
V. And ee , M. Aza kin, I. D emin, M. Ki akosyan, A. Leonido , S.V. Rusako , A. Vinog ado
S a e Resea ch Cen e o Russian Fede a ion, Ins i u e o High Ene gy Physics, P o ino,
Russia
I. Azhgi ey, S. Bi iouko , V. G ishin1, V. Kachano , D. Kons an ino , A. Ko able , V. K ychkine,
V. Pe o , R. Ryu in, S. Slabospi sky, A. Sobol, L. Tou chano i ch, S. T oshin, N. Tyu in,
A. Uzunian, A. Volko
Uni e si y o Belg ade, Facul y o Physics and Vinca Ins i u e o Nuclea Sciences, Belg ade,
Se bia
P. Adzic20, M. Djo dje ic, D. K pic20, J. Milose ic
Cen o de In es igaciones Ene g´e icas Medioambien ales y Tecnol´ogicas (CIEMAT),
Mad id, Spain
M. Aguila -Beni ez, J. Alca az Maes e, P. A ce, C. Ba ilana, E. Cal o, M. Cepeda, M. Ce ada,
M. Chamizo Lla as, N. Colino, B. De La C uz, A. Delgado Pe is, C. Diez Pa dos, D. Dom´
ınguez
V´
azquez, C. Fe nandez Bedoya, J.P. Fe n´
andez Ramos, A. Fe ando, J. Flix, M.C. Fouz,
22 A The CMS Collabo a ion
P. Ga cia-Abia, O. Gonzalez Lopez, S. Goy Lopez, J.M. He nandez, M.I. Josa, G. Me ino,
J. Pue a Pelayo, I. Redondo, L. Rome o, J. San aolalla, M.S. Soa es, C. Willmo
Uni e sidad Au ´onoma de Mad id, Mad id, Spain
C. Albaja , G. Codispo i, J.F. de T oc´
oniz
Uni e sidad de O iedo, O iedo, Spain
J. Cue as, J. Fe nandez Menendez, S. Folgue as, I. Gonzalez Caballe o, L. Llo e Iglesias,
J.M. Vizan Ga cia
Ins i u o de F´ısica de Can ab ia (IFCA), CSIC-Uni e sidad de Can ab ia, San ande , Spain
J.A. B oche o Ci uen es, I.J. Cab illo, A. Calde on, S.H. Chuang, J. Dua e Campde os,
M. Felcini21, M. Fe nandez, G. Gomez, J. Gonzalez Sanchez, C. Jo da, P. Lobelle Pa do, A. Lopez
Vi o, J. Ma co, R. Ma co, C. Ma inez Ri e o, F. Ma o as, F.J. Munoz Sanchez, J. Pied a
Gomez22, T. Rod igo, A.Y. Rod ´
ıguez-Ma e o, A. Ruiz-Jimeno, L. Scodella o, M. Sob on
Sanudo, I. Vila, R. Vila Co abi a e
CERN, Eu opean O ganiza ion o Nuclea Resea ch, Gene a, Swi ze land
D. Abbaneo, E. Au ay, G. Auzinge , P. Baillon, A.H. Ball, D. Ba ney, A.J. Bell23, D. Benede i,
C. Be ne 3, W. Bialas, P. Bloch, A. Bocci, S. Bolognesi, M. Bona, H. B euke , G. B ona,
K. Bunkowski, T. Campo esi, G. Ce mina a, J.A. Coa asa Pe ez, B. Cu ´
e, D. D’En e ia,
A. De Roeck, S. Di Guida, A. Ellio -Peise , B. F isch, W. Funk, A. Gaddi, S. Gennai,
G. Geo giou, H. Ge wig, D. Gigi, K. Gill, D. Gio dano, F. Glege, R. Gomez-Reino Ga ido,
M. Gouze i ch, P. Go oni, S. Gowdy, L. Guiducci, M. Hansen, C. Ha l, J. Ha ey, J. Hegeman,
B. Hegne , H.F. Ho mann, A. Honma, V. Innocen e, P. Jano , K. Kaadze, E. Ka a akis,
P. Lecoq, C. Lou enc¸o, T. M¨
aki, L. Malge i, M. Mannelli, L. Mase i, F. Meije s, S. Me si,
E. Meschi, R. Mose , M.U. Moze , M. Mulde s, E. Nes old1, M. Nguyen, T. O imo o, L. O sini,
E. Pe ez, A. Pe illi, A. P ei e , M. Pie ini, M. Pimi¨
a, G. Polese, A. Racz, J. Rod igues An unes,
G. Rolandi24, T. Romme ski chen, C. Ro elli25, M. Ro e e, H. Sakulin, C. Sch¨
a e , C. Schwick,
I. Segoni, A. Sha ma, P. Sieg is , M. Simon, P. Sphicas26, M. Spi opulu19, F. S ¨
ockli, M. S oye,
P. T opea, A. Tsi ou, P. Vichoudis, M. Vou ilainen, W.D. Zeune
Paul Sche e Ins i u , Villigen, Swi ze land
W. Be l, K. Dei e s, W. E dmann, K. Gaba hule , R. Ho isbe ge , Q. Ing am, H.C. Kaes li,
S. K¨
onig, D. Ko linski, U. Langenegge , F. Meie , D. Renke , T. Rohe, J. Sibille27,
A. S a odumo 28
Ins i u e o Pa icle Physics, ETH Zu ich, Zu ich, Swi ze land
P. Bo ignon, L. Caminada29, Z. Chen, S. Ci olin, G. Disse o i, M. Di ma , J. Eugs e ,
K. F euden eich, C. G ab, A. He ´
e, W. Hin z, P. Lecom e, W. Lus e mann, C. Ma chica29,
P. Ma inez Ruiz del A bol, P. Me idiani, P. Mileno ic30, F. Moo ga , P. Ne , F. Nessi-Tedaldi,
L. Pape, F. Pauss, T. Punz, A. Rizzi, F.J. Ronga, M. Rossini, L. Sala, A.K. Sanchez, M.-C. Sawley,
B. S iege , L. Tausche †, A. Thea, K. Theo ila os, D. T eille, C. U schele , R. Wallny, M. Webe ,
L. Weh li, J. Weng
Uni e si ¨a Z¨u ich, Zu ich, Swi ze land
E. Aguil´
o, C. Amsle , V. Chiochia, S. De Vissche , C. Fa a o, M. I o a Riko a, B. Millan Mejias,
P. O iougo a, C. Regen us, P. Robmann, A. Schmid , H. Snoek
Na ional Cen al Uni e si y, Chung-Li, Taiwan
Y.H. Chang, E.A. Chen, K.H. Chen, W.T. Chen, S. Du a, C.M. Kuo, S.W. Li, W. Lin, M.H. Liu,
Z.K. Liu, Y.J. Lu, D. Mek e o ic, J.H. Wu, S.S. Yu
23
Na ional Taiwan Uni e si y (NTU), Taipei, Taiwan
P. Ba alini, P. Chang, Y.H. Chang, Y.W. Chang, Y. Chao, K.F. Chen, W.-S. Hou, Y. Hsiung,
K.Y. Kao, Y.J. Lei, R.-S. Lu, J.G. Shiu, Y.M. Tzeng, M. Wang
Cuku o a Uni e si y, Adana, Tu key
A. Adiguzel, M.N. Baki ci31, S. Ce ci32, C. Dozen, I. Dumanoglu, E. Esku , S. Gi gis,
G. Gokbulu , Y. Gule , E. Gu pina , I. Hos, E.E. Kangal, T. Ka aman, A. Kayis Topaksu,
A. Na , G. Onengu , K. Ozdemi , S. Oz u k, A. Pola oz, K. Sogu 33, D. Suna Ce ci32, B. Tali,
H. Topakli31, D. Uzun, L.N. Ve gili, M. Ve gili, C. Zo bilmez
Middle Eas Technical Uni e si y, Physics Depa men , Anka a, Tu key
I.V. Akin, T. Alie , S. Bilmis, M. Deniz, H. Gamsizkan, A.M. Gule , K. Ocalan, A. Ozpineci,
M. Se in, R. Se e , U.E. Su a , E. Yildi im, M. Zey ek
Bogazici Uni e si y, Is anbul, Tu key
M. Deliome oglu, D. Demi 34, E. G¨
ulmez, B. Isildak, M. Kaya35, O. Kaya35, S. Ozko ucuklu36,
N. Sonmez37
Na ional Scien i ic Cen e , Kha ko Ins i u e o Physics and Technology, Kha ko , Uk aine
L. Le chuk
Uni e si y o B is ol, B is ol, Uni ed Kingdom
P. Bell, F. Bos ock, J.J. B ooke, T.L. Cheng, E. Clemen , D. Cussans, R. F azie , J. Golds ein,
M. G imes, M. Hansen, D. Ha ley, G.P. Hea h, H.F. Hea h, B. Huck ale, J. Jackson, L. K eczko,
S. Me son, D.M. Newbold38, K. Ni unpong, A. Poll, S. Senkin, V.J. Smi h, S. Wa d
Ru he o d Apple on Labo a o y, Didco , Uni ed Kingdom
L. Basso39, K.W. Bell, A. Belyae 39, C. B ew, R.M. B own, B. Camanzi, D.J.A. Cocke ill,
J.A. Coughlan, K. Ha de , S. Ha pe , B.W. Kennedy, E. Olaiya, D. Pe y , B.C. Radbu n-Smi h,
C.H. Shephe d-Themis ocleous, I.R. Tomalin, W.J. Wome sley, S.D. Wo m
Impe ial College, London, Uni ed Kingdom
R. Bainb idge, G. Ball, J. Ballin, R. Beuselinck, O. Buchmulle , D. Colling, N. C ipps, M. Cu aja ,
G. Da ies, M. Della Neg a, J. Fulche , D. Fu yan, A. Gilbe , A. Gune a ne B ye , G. Hall,
Z. Ha he ell, J. Hays, G. Iles, G. Ka apos oli, L. Lyons, B.C. MacE oy, A.-M. Magnan,
J. Ma ouche, R. Nandi, J. Nash, A. Niki enko28, A. Papageo giou, M. Pesa esi, K. Pe idis,
M. Pioppi40, D.M. Raymond, N. Rompo is, A. Rose, M.J. Ryan, C. Seez, P. Sha p, A. Spa ow,
A. Tappe , S. Tou neu , M. Vazquez Acos a, T. Vi dee, S. Wake ield, D. Wa d ope, T. Whyn ie
B unel Uni e si y, Uxb idge, Uni ed Kingdom
M. Ba e , M. Chadwick, J.E. Cole, P.R. Hobson, A. Khan, P. Kybe d, D. Leslie, W. Ma in,
I.D. Reid, L. Teodo escu
Baylo Uni e si y, Waco, USA
K. Ha akeyama
Bos on Uni e si y, Bos on, USA
T. Bose, E. Ca e a Ja in, C. Fan asia, A. Heis e , J. S . John, P. Lawson, D. Lazic, J. Rohl ,
D. Spe ka, L. Sulak
B own Uni e si y, P o idence, USA
A. A e isyan, S. Bha acha ya, J.P. Chou, D. Cu s, A. Fe apon o , U. Hein z, S. Jabeen,
G. Kuka se , G. Landsbe g, M. Na ain, D. Nguyen, M. Segala, T. Spee , K.V. Tsang