The differential production cross section of the $\phi $ (1020) meson in $\sqrt{s}$ = 7 TeV $pp$ collisions measured with the ATLAS detector

EUROPEAN ORGANISATION FOR NUCLEAR RESEARCH (CERN)

CERN-PH-EP-2012-269

Submitted to: EPJC

The differential production cross section of the φ(1020) meson

in

√

s = 7 TeV

pp collisions measured with the ATLAS detector

The ATLAS Collaboration

Abstract

A measurement is presented of the φ → K

K

production cross section at

√

s

= 7 TeV using

pp

collision data corresponding to an integrated luminosity of 383 µb

, collected with the ATLAS

experiment at the LHC. Selection of φ(1020) mesons is based on the identification of charged kaons

by their energy loss in the pixel detector. The differential cross section is measured as a function of the

transverse momentum, p

, and rapidity, y

, of the φ(1020) meson in the fiducial region 500 < p

<

1200 MeV, |yφ| < 0.8, kaon pT,K

>

230 MeV and kaon momentum pK

<

800 MeV. The integrated

φ(1020)-meson production cross section in this fiducial range is measured to be σ

= 570 ± 8

(stat) ± 66 (syst) ± 20 (lumi) µb.

c

2014 CERN for the benefit of the ATLAS Collaboration.

Eur. Phys. J. C manuscript No. (will be inserted by the editor)

The differential production cross section of the φ(1020)

meson in

√

s = 7 TeV pp collisions measured with the

ATLAS Detector

The ATLAS Collaboration

1_CERN

Received: March 31 2014

Abstract A measurement is presented of the φ → K+_K− _{production cross section at} √_{s = 7 TeV}

using pp collision data corresponding to an inte-grated luminosity of 383 µb−1, collected with the ATLAS experiment at the LHC. Selection of φ(1020) mesons is based on the identification of charged kaons by their energy loss in the pixel detector. The differential cross section is measured as a func-tion of the transverse momentum, pT,φ, and

rapid-ity, yφ, of the φ(1020) meson in the fiducial region

500 < pT,φ < 1200 MeV, |yφ| < 0.8, kaon pT,K >

230 MeV and kaon momentum pK < 800 MeV. The

integrated φ(1020)-meson production cross section in this fiducial range is measured to be σφ→K+_K−

= 570 ± 8 (stat) ± 66 (syst) ± 20 (lumi) µb. PACS 13.85.Ni · 14.40.Df · 14.40.Aq · 14.40.Be

1 Introduction

Perturbative quantum chromodynamics (QCD) suc-cessfully describes physics at high momentum trans-fer, while phenomenological models are needed for soft interactions at lower momentum transfers. An accurate description of these soft interactions is re-quired to model so-called underlying events present in hard scattering events. Measurements of the φ (1020)-meson probe strangeness production at a soft scale Q ∼ 1 GeV, which is sensitive to s-quark and low-x gluon densities. Production of φ(1020) mesons is also sensitive to fragmentation details and thus φ(1020) measurements can constrain phe-nomenological soft hadroproduction models.

This paper presents a measurement with the ATLAS detector [1] of the φ(1020)-meson produc-tion cross secproduc-tion in pp interacproduc-tions at√s = 7 TeV,

using the φ → K+_K− _{decay mode. The cross}

section is measured in bins of transverse momen-tum, pT,φ, or of rapidity |yφ|.1 The selection of

φ(1020)-meson candidates requires the identifica-tion of kaons in order to reduce the large combi-natorial background from other charged particles. Charged particles are reconstructed with the inner detector, which consists of a silicon pixel detector, a microstrip semiconductor tracker (SCT), and a straw-tube transition radiation tracker (TRT). The inner detector barrel (end-cap) parts consist of 3 (2 × 3) pixel layers, 4 (2 × 9) layers of double-sided silicon strip modules, and 73 (2 × 160) lay-ers of TRT straws. A track travlay-ersing the barrel typically has 11 silicon hits (3 pixel clusters, and 8 strip clusters), and more than 30 straw-tube hits. The whole inner detector is immersed in a 2 T axial magnetic field. The specific energy loss of charged particles in the pixel detector is used to identify low-momentum pions, kaons and protons [2].

To avoid model-dependent extrapolations out-side the detector acceptance, the cross section is measured in the fiducial region, defined as 500 < pT,φ< 1200 MeV, |yφ| < 0.8, kaon transverse

mo-mentum pT,K > 230 MeV and kaon momentum

pK < 800 MeV. In the region 0.8 < |yφ| < 1.0,

φ(1020) decays would only be accepted up to pT,φ∼

700 MeV, because the requirement of pK< 800 MeV

1_{ATLAS uses a right-handed coordinate system with}

its origin at the nominal interaction point (IP) in the centre of the detector and the z-axis along the beam pipe. The x-axis points from the IP to the centre of the LHC ring, and the y-axis points upward. Cylindrical coordinates (r, φ) are used in the transverse plane, φ being the azimuthal angle around the beam pipe. The pseudorapidity is defined in terms of the polar angle θ with respect to the beamline as η = −ln[tan(θ/2)].

has a lower efficiency at higher rapidity. The fidu-cial range is limited to the region where the dif-ferential cross section can be measured and where correcting for the losses due to the requirements on kaon momentum is reliable. The measurement is corrected for detector effects and can be com-pared directly with Monte Carlo (MC) generators at particle level.

Many measurements of the φ(1020) production cross section have been performed at different centre-of-mass energies, using different decay modes and in different rapidity ranges. Among these are a study at √s = 7 TeV by ALICE [3] in a similar rapidity region and another by LHCb [4] in the forward rapidity region. The φ(1020) production cross section presented in this paper is compared to the measurement by ALICE and to MC predic-tions.

2 Data set and event selection

A data sample with an integrated luminosity of 383 µb−1from pp collision data taken in April 2010 at√s = 7 TeV is used. The contribution of pile-up, i.e. multiple collisions per bunch crossing, is negli-gible for this data sample, with a peak luminosity of 1.8 · 1028cm−2s−1. The luminosity is measured in dedicated van der Meer scans with an estimated uncertainty of 3.5% [5]. The data sample was se-lected with the minimum bias trigger scintillators (MBTS) [6] to minimize any possible bias in the measured cross section. The MBTS are mounted at each end of the tracking detector in front of the liquid-argon endcap-calorimeter cryostats at z = ± 3.56 m and were configured to require one hit above threshold from either side of the detector. This trigger is shown to be highly efficient in se-lecting inelastic pp collisions [6]. Tracks are fitted with a kaon-mass assumption to account for energy losses in the detector material. Events are required to contain at least two tracks with pT> 150 MeV

and to have a primary vertex (PV, defined as the vertex in the event with the largest ΣpT over all

reconstructed tracks associated to the vertex) [7] reconstructed using the beam spot information [6]. MC simulations are used to correct the data for detector effects and to compare with the fully cor-rected data. The MC generators used are PYTHIA 6 [8], PYTHIA 8 [9], Herwig++ [10] and EPOS [11, 12]. Different versions of the same MC generator, that differ in sets of tunable parameters used in mod-eling the soft component of proton-proton interac-tions, are called tunes. Both PYTHIA 6 and PYTHIA 8

are general purpose generators which implement the Lund string hadronisation model [13] and de-scribe non-diffractive interactions (including Mul-tiple Parton Interactions, MPI) via lowest-order perturbative QCD, with phenomenological regu-larisation of the divergence of the cross section as pT → 0. Diffractive processes are included which

involve the exchange of a colour singlet. Both in-elastic non-diffractive and diffractive processes are mixed in accordance with the generator cross sec-tions. The PYTHIA tunes considered are MC09 [14] with PYTHIA 6 version 6.421, DW [15] and Peru-gia0 [16] with PYTHIA 6 version 6.423, and two A2 tunes with PYTHIA 8 version 8.153, i.e. with the MSTW2008LO [17, 18] and CTEQ6L1 [19] PDF sets. The MC09 and Perugia0 tunes use a pT

-order-ed parton shower model with MPI and the initial-state shower interleaved in a common sequence of decreasing pT. For the PYTHIA 8 A2 tunes, the

final-state showers are also interleaved in this way. The DW tune utilises the older virtuality-ordered parton shower which is not interleaved with MPI. Herwig++ version 2.5.1 is used with the UE7-2 [UE7-20] tune. Herwig++ is also a general purpose generator but differs from PYTHIA in that it uses a cluster hadronisation model [21] and an angular-ordered parton shower. Herwig++ contains a tun-able eikonalised MPI model which assumes inde-pendence between separate scatters in the event. In order to simulate inelastic minimum bias events the following mechanism is used. For a fixed im-pact parameter, Poisson distributions are sampled to provide the number of soft and perturbatively-treated semi-hard scatters to simulate per event.

EPOS 1.99 v2965 is used with the EPOS-LHC [22] tune. EPOS contains a parametrised approximation of the hydrodynamic evolution of initial states us-ing a parton based Gribov-Regge [23] theory which has been tuned to LHC data.

The ATLAS detector is simulated [24] using GEANT4 [25]. The reconstruction of K±tracks from φ → K+_K− _{decays generated by PYTHIA 6 MC09}

is used for the calculation of the tracking efficiency. A consistency test of the full φ(1020)-meson recon-struction is performed with PYTHIA 6 MC09 and Herwig++ UE7-2.

As the φ(1020) meson has no measurable de-cay length, only tracks originating from the PV are used. Each track must pass the following require-ments: more than one pixel cluster and more than one SCT hit; pT > 230 MeV; p < 800 MeV and

|η| < 2.0. The condition pT> 230 MeV is adopted

Fig. 1: The truncated mean (see text for detailed explanation) for the energy loss per track as a func-tion of signed momentum for tracks accepted in the analysis. The bands corresponding to the en-ergy lost by pions, kaons and protons are labelled.

pT,K < 230 MeV and central |η| is close to zero.

Kaons produced with such low momenta effectively deposit all their energy in the detector and sup-port materials before reaching the SCT. The cut on track momentum of p < 800 MeV is dictated by particle identification requirements and is ex-plained in the next section.

3 Particle identification

Every pair of oppositely charged tracks passing the tracking cuts is examined. The identification of a pair of tracks candidate for a φ → K+_K−

de-cay requires a particle identification (PID) step to remove the large combinatorial background from pairs containing one or two charged particles that are not kaons. Discrimination between background (consisting mostly of pions) and kaons is achieved using energy loss in the pixel detector. The mean energy deposited by a charged particle is described by the Bethe–Bloch formula as a function of the particle’s velocity [26]. For momenta larger than 1 GeV, the energy lost by the particles starts to be dominated by relativistic effects and can no longer be used for particle identification. The mean en-ergy loss per unit length is estimated as the enen-ergy deposited by a particle in the traversed layers of the pixel detector divided by the local thickness

traversed in the detector material. The energy de-posited is calculated after removing the pixel clus-ter with the largest charge for particles with three or four associated pixel clusters or after removing the two clusters with the largest charge for parti-cles with more than four pixel clusters. The track dE/dx is calculated using a truncated mean of the dE/dx values of the individual pixel clusters as this gives a better resolution than the simple mean. The expected energy loss for a kaon with pK =

500 MeV is 2.4 MeV g−1 cm2_{. For a pion with the}

same momentum, an energy loss of 1.2 MeV g−1 cm2is expected. The average energy loss per track as a function of signed momentum, qp, where q is the particle charge, is shown in Fig. 1; bands indi-cating pions, kaons and protons are clearly visible. A comparison between data and MC prediction of track η, of the number of hits in the pixel and SCT detectors associated with tracks (with a re-quirement of at least two pixel clusters and two SCT hits) and of average energy loss per track is presented in Fig. 2. The distributions agree well, demonstrating a good understanding of track sim-ulation and reconstruction in the inner detector. The slight disagreement in Fig. 2(a), where the lo-cation of the peak of the average energy loss is overestimated by ∼0.05 MeV g−1 cm2 _{in the MC}

simulation, is due to the relative abundances of different particle species being slightly different for data and simulation.

The most probable value of the specific energy loss for a pion, kaon or proton hypothesis is para-meterized as a function of the charged particle’s Lorentz factor βγ. The measured energy loss is used to calculate the probability Pparticle of

com-patibility with a given hypothesis [2]. Kaon can-didates are required to satisfy Ppion < 0.1 and

Pkaon > 0.84 conditions. The candidate φ(1020)

decays are searched for by selecting the oppositely charged track pairs for which both tracks pass the tracking and PID requirements defined above and combine to an invariant mass in the range 1000 < m(K+_K−_{) < 1060 MeV.}

4 Determination of the cross section

The fiducial region is divided into eight bins in |yφ|

and ten bins in pT,φ with bin widths of 0.1 and

70 MeV, respectively. Unless specifically stated, the cross section is not corrected for the branching fraction of φ(1020)-meson decays to kaons.

Each φ(1020) candidate is assigned a weight to correct for experimental losses. Firstly, a weight is

η Track -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 Normalized Entries / 0.1 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 7 TeV data PYTHIA 6 ATLAS (a)

Number of pixel clusters per track 0 1 2 3 4 5 6 7 8 9 Normalized Entries 0 0.1 0.2 0.3 0.4 0.5 0.6 7 TeV data PYTHIA 6 ATLAS (b)

Number of SCT clusters per track 0 2 4 6 8 10 12 14 Normalized Entries 0 0.1 0.2 0.3 0.4 0.5 0.6 7 TeV data PYTHIA 6 ATLAS (c) ] 2 cm -1 Track dE/dx [MeV g 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 Normalized Entries / 0.05 -4 10 -3 10 -2 10 -1 10 ATLAS 7 TeV data PYTHIA 6 (d)

Fig. 2: Comparison between data (black dots) and MC simulation (histogram) for (a) track η, (b) number of pixel clusters assigned to the track, (c) number of SCT clusters assigned to the track and (d) the average track energy loss (see text). Statistical uncertainties are smaller than the marker size.

given for trigger and vertex reconstruction efficien-cies [6], which have both been measured in data to rapidly increase to 100% for events with four or more tracks. The trigger and vertex reconstruction efficiencies were found to have a negligible effect on this analysis and were applied on an event-by-event basis. Secondly, a weight is given for track re-construction and kaon identification efficiencies on a track-by-track basis. These efficiencies are calcu-lated separately for tracks from positively and neg-atively charged particles, because fewer pixel clus-ters are expected on the tracks of low-momentum negatively charged particles, which may pass in be-tween two pixel modules due to the tiling and tilt of the modules. The average number of pixel clus-ters on tracks which pass the selection detailed in Sect. 2 is 2.96±0.01 per positively charged particle and 2.79 ± 0.01 per negatively charged particle. Fi-nally, a weight is given on a track-by-track basis to correct for the fraction of selected tracks passing the kinematic selection for which the correspond-ing truth kaon is outside the kinematic range.

Fol-lowing the determination of the weight of each of the candidate φ(1020), the efficiency-corrected number of reconstructed candidates is determined with a fit to the invariant mass distribution.

The calculation of track reconstruction efficiency, kaon identification efficiency and the subsequent signal yield extraction are explained in the next sections.

4.1 Track reconstruction efficiency

The track reconstruction efficiency, rec, is based

on MC ‘truth-matching’, where generated particles are matched to reconstructed tracks. The method is based on a matching probability evaluated using the number of common hits between particles at generator level and the reconstructed tracks, and is described in Ref. [6]. The average tracking effi-ciency for the two tracks of a φ → K+_K− _decay

is about 40% for the lower pT,φbins and increases

to 65% in the highest pT,φ bin. It is ∼ 50% for all

To estimate the quality of the MC description of recin data, the number of tracks passing all cuts

in bins of pseudorapidity is divided by the number of tracks passing the cuts with one cut loosened. This efficiency is referred to as the relative effi-ciency rel. The behavior of relwith one fewer pixel

cluster or one fewer SCT hit required per track and a lower momentum cut is compared between simu-lation and data and found to be consistent within 0.5%. The systematic uncertainty inferred is 0.7% per track pair.

The dominant source of uncertainty is due to uncertainty in the MC material description, de-noted as rec(material). It is described in Ref. [6]

and is given in bins of track η and pT. The

mate-rial uncertainty, expressed as a fraction of the cor-responding tracking efficiency, is 2–3% for most tracks accepted in this analysis. To evaluate the impact of this uncertainty, the yield is extracted with the nominal tracking efficiency, and with the nominal tracking efficiency varied up and down by this uncertainty. The systematic uncertainty aris-ing from rec(material) is accounted for per bin in

pT,φ or |yφ| and is 5% per track pair.

The number of reconstructed decays is corrected for the fraction of selected tracks passing the kine-matic selection for which the corresponding pri-mary particle is outside the kinematic range. The distributions are subsequently corrected using a MC derived factor to account for the migration of reconstructed φ(1020)-meson candidates into the fiducial volume. The systematic uncertainty aris-ing from this migration correction is evaluated by re-calculating the migration correction after re-wei-ghting the kaon momentum spectrum at particle-level to get a good description of the data at detec-tor level. The variation of the extracted yield using the default and re-weighted migration correction is assigned as a systematic uncertainty and is below 1%.

The statistical uncertainty on the tracking effi-ciency, rec(stat), is in the range 1–5% and is

prop-agated as a systematic uncertainty on the cross section. The total systematic uncertainty in the tracking efficiency determination is obtained by adding the previously mentioned components in quadrature and is summarized in Tables 1 and 2 as a function of pT,φ and |yφ|, respectively.

4.2 Particle identification efficiency

The particle identification efficiency, pid, is

ex-tracted from simulation as a function of both pK

and η. The data sample is not large enough to determine the PID efficiency with a purely data driven technique in bins of pK and η. Therefore a

data-driven tag-and-probe technique is used to de-termine the PID in bins of pK and this is used to

rescale the Monte Carlo estimates of the PID effi-ciency. The data sample is split up into five bins of pK and the efficiency is measured as the fraction

Nprobe/Ntag, where Nprobe is the number of

can-didates for which both kaons pass the PID requi-rement of Ppion< 0.1 and Pkaon> 0.84, and Ntag

is the number of candidates for which at least the K+or the K−passes. To measure the signal yields Ntagand Nprobe, the invariant mass distribution in

each bin of pK is fitted with a probability density

function (p.d.f.) that describes the signal and back-ground contributions separately and which is de-tailed in Sect. 4.3. A final efficiency correction fac-tor is defined by multiplying the two-dimensional efficiency from MC simulation by the ratio of data to MC tag-and-probe efficiencies, which is close to unity for pK< 500 MeV, but decreases to a factor

of slightly more than 0.3 for 700 < pK< 800 MeV.

The tag-and-probe method is validated using MC simulation by ascertaining that the pidvalues

obtained using MC truth-matching and the tag-and-probe method in bins of pT,φ and |yφ| agree

within MC statistical uncertainties. The particle identification efficiency decreases with increasing average kaon momentum from ∼90% for 230 < pK≤ 400 MeV to ∼10% for 700 < pK < 800 MeV.

The systematic uncertainty due to pid is

eval-uated by fixing the background shape parameters in the tag sample to the values given by the fit to the same-sign background distribution (a maxi-mum uncertainty of 10%) and by adding the same-sign background samples to the fitted data sets for the tag-and-probe validation in PYTHIA 6 to vary the signal to background ratio (a maximum un-certainty of 6%). Possible dependence of the cross section on the choice of Pkaonrequirement is tested

by varying the requirement by 10% and is found to be well within the uncertainty due to fixing the background shape parameters. The statistical uncertainty on pid is calculated using a binomial

probability distribution, which leads to a relative uncertainty on pid of at most 5%, denoted by

pid(stat). These uncertainties (evaluated per bin

in pT,φ or |yφ|) are added in quadrature and are

included as systematic uncertainties on the cross section as summarized in Tables 1 and 2.

4.3 Signal extraction

To extract the signal yields, a binned χ2_{fit to the}

invariant mass spectrum is performed in each re-gion of phase space after applying corrections for the selection efficiencies to the tracks. The signal shape is described by a relativistic Breit–Wigner, fRBW(m; m0, Γ0) =

m2

(m2_{− m}2

0)2+ m20Γ2(m)

, (1) where the mass-dependent width is given by

Γ (m) = Γ0  m2_{− 4m}2 K m2 0− 4m2K 3/2 . (2)

In Eq. (1), m0is fixed to the φ(1020)-meson mass

of 1019.45 MeV [27], Γ0 to the natural width of

4.26 MeV [27], and mK in Eq. (2) is the charged

kaon mass [27].

The signal shape is convolved with a Gaus-sian resolution function, with the mean and stan-dard deviation left free in the fit. The mean of the Gaussian is interpreted as the actual value of the φ(1020) mass, while its standard deviation corre-sponds to the experimental resolution. The values obtained from the fits are in the range σexp =1.0–

2.5 MeV.

This signal description is added to an empirical background description, fBKG(m) =  1 − e(2mK−m)/C_·  _m 2mK A +B  m 2mK − 1  , (3) where A, B and C determine the background shape. Initial values for A, B and C are found by fit-ting the background p.d.f. to a sample of events with two kaons of the same charge. This same-sign sample contains the same sources of combinato-rial background as the nominal selection but no true φ(1020) mesons, and so it provides a good initial description of the background shape. It was checked that the background model provides sta-ble fitting results in all bins in pT,φ and |yφ| for

the same-sign sample.

Fits of the invariant mass of K+_K− _{pairs are}

shown in Fig. 3 for four regions. It was found that the maximum of the signal peak, mpeak, is shifted

upwards by almost 1 MeV for the lowest pT,φ bin.

This is covered by the uncertainty on the momen-tum scale for the low-momenmomen-tum tracks.

Three tests are conducted to estimate the sys-tematic uncertainty on the extracted signal yield due to uncertainty on the signal, background shape

and detector resolution. Firstly, the signal is ex-tracted using a non-relativistic Breit–Wigner line-shape convolved with a Gaussian to describe the signal shape. This leads to a conservative estimate of the uncertainties in the extracted signal of 5–6%, which are evaluated bin-by-bin in pT,φ and |yφ|.

Secondly, the extracted yield changes by at most 2% if the signal shape is convolved with a Crystal Ball [28] resolution function, rather than a Gaus-sian. Thirdly, the extracted yields vary by at most 3% if the background p.d.f. is fitted to the sample of same-sign pairs of tracks in each bin and the shape is fixed to the result of this fit. Adding the relative changes in the yield in quadrature, a con-servative estimate of 6–7% is assigned to the sys-tematic uncertainty and summarized in Tables 1 and 2.

The cross section σ_bini in bin i is determined by

σi_bin= Ni

L , (4)

where L is the integrated luminosity and Ni is the

number of efficiency-corrected reconstructed φ → K+_K− _{candidates in bin i.}

5 Results

The differential φ → K+_K− _{cross section in the}

fiducial region 500 < pT,φ< 1200 MeV, |yφ| < 0.8,

kaon transverse momentum pT,K > 230 MeV and

kaon momentum pK < 800 MeV is shown in Fig. 4

as functions of pT,φand |yφ| and compared to

sim-ulation. Tables 1 and 2 give the differential cross sections and the relevant systematic uncertainties. The total statistical uncertainty ranges from 3% to 8% and the total systematic uncertainty is 8–12%. The uncertainty on the luminosity is 3.5% [5] for all bins. The integrated cross section is calculated as the sum of the differential cross sections as a function of pT,φ. This determination is less

sensi-tive to mismodelling of the pT,φ distribution and

is measured to be σφ→K+_K− = 570 ± 8 (stat) ±

68 (syst) ± 20 (lumi) µb.

The fiducial cross section increases as a func-tion of pT,φ in the range 500–700 MeV, reaches a

maximum at pT,φ ∼ 750 MeV and decreases for

pT,φ ≥ 850 MeV. The increase in the number of

measured decays as pT,φ rises to 700 MeV is due

to the cut on kaon transverse momentum pT,K >

230 MeV. Being within the rapidity plateau at the LHC given that |yφ| < 0.8, the total φ(1020) cross

section differential in |yφ| is expected to be

) [MeV] -K + m(K 1000 1010 1020 1030 1040 1050 1060 W e ig h te d E n tr ie s / M e V 0 1000 2000 3000 4000 s = 7 TeV, L=383 µb-1 4 10 ⋅ 0.07) ± signal yield = (1.22 0.1 MeV ± = 2.3 exp σ 0.9 MeV ± = 1020.6 peak m /ndof = 0.9 2 χ < 570 MeV φ T, 500 < p ATLAS (a) ) [MeV] -K + m(K 1000 1010 1020 1030 1040 1050 1060 W e ig h te d E n tr ie s / M e V 0 1000 2000 3000 4000 5000 6000 7000 -1 b µ = 7 TeV, L=383 s 4 10 ⋅ 0.10) ± signal yield = (2.85 0.2 MeV ± = 2.8 exp σ 0.3 MeV ± = 1019.9 peak m /ndof = 1.2 2 χ < 920 MeV φ T, 850 <p ATLAS (b) ) [MeV] -K + m(K 1000 1010 1020 1030 1040 1050 1060 W e ig h te d E n tr ie s / M e V 0 1000 2000 3000 4000 5000 6000 s = 7 TeV, L=383 µb-1 ₄ 10 ⋅ 0.10) ± signal yield = (3.44 0.2 MeV ± = 2.2 exp σ 0.9 MeV ± = 1020.4 peak m /ndof = 1.1 2 χ | < 0.1 φ |y ATLAS (c) ) [MeV] -K + m(K 1000 1010 1020 1030 1040 1050 1060 W e ig h te d E n tr ie s / M e V 0 1000 2000 3000 4000 5000 -1 b µ = 7 TeV, L=383 s 4 10 ⋅ 0.07) ± signal yield = (1.18 0.2 MeV ± = 1.4 exp σ 0.9 MeV ± = 1020.4 peak m /ndof = 1.1 2 χ | < 0.8 φ 0.7 < |y ATLAS (d)

Fig. 3: Examples of invariant K+_K− _{mass distributions in the data (dots) compared to results of the}

fits (solid lines), as described in the text, for (a) the lowest pT,φ bin, (b) one of the middle pT,φ bins,

(c) the most central |yφ| bin and (d) most forward |yφ| bin. The dashed curves show the background

contribution and the dotted red curves demonstrates the signal contributions, with paremeters listed in the legend. b/MeV] µ [_T )/dp -K + K → φ ( σ d 0 0.5 1 1.5 2 2.5 Data PYTHIA 6 MC09 PYTHIA 6 DW PYTHIA 6 Perugia0 PYTHIA 8 A2:MSTW2008LO PYTHIA 8 A2:CTEQ6L1 HERWIG++ EPOS-LHC ATLAS -1 b µ = 7 TeV, L = 383 s < 800 MeV K > 230 MeV, p T,K | < 0.8, p φ |y Data PYTHIA 6 MC09 PYTHIA 6 DW PYTHIA 6 Perugia0 PYTHIA 8 A2:MSTW2008LO PYTHIA 8 A2:CTEQ6L1 HERWIG++ EPOS-LHC [MeV] φ T, p 500 600 700 800 900 1000 1100 1200 Data/MC 1 1.5 2 2.5 b] µ )/d|y| [ -K + K → φ ( σ d 0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 Data PYTHIA 6 MC09 PYTHIA 6 DW PYTHIA 6 Perugia0 PYTHIA 8 A2:MSTW2008LO PYTHIA 8 A2:CTEQ6L1 HERWIG++ EPOS-LHC ATLAS -1 b µ = 7 TeV, L = 383 s < 1200 MeV φ T, 500 < p < 800 MeV K > 230 MeV, p T,K p Data PYTHIA 6 MC09 PYTHIA 6 DW PYTHIA 6 Perugia0 PYTHIA 8 A2:MSTW2008LO PYTHIA 8 A2:CTEQ6L1 HERWIG++ EPOS-LHC | φ |y 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 Data/MC 1 1.5 2 2.5

Fig. 4: The φ(1020) → K+_K− _{cross section in the fiducial region, with 500 < p}

T,φ< 1200 MeV, |yφ| <

0.8, pT,K > 230 MeV and kaon momentum pK< 800 MeV, as a function of pT,φ (left) and |yφ| (right).

The error bars represent the statistical uncertainty and the green boxes represent the quadratic sum of the statistical and systematic uncertainties. The 3.5% uncertainty on the luminosity is not included. The data are compared to various MC expectations as described in the legends.

Table 1: The fitted number of φ(1020) candidates (Signal), the differential production cross sec-tion dσ/dpT [µb/MeV] of φ → K+K− and its statistical uncertainty in bins of pT,φ with 500 <

pT,φ < 1200 MeV, |yφ| < 0.8, pT,K > 230 MeV and pK < 800 MeV and the systematic

uncertain-ties due to track reconstruction efficiency (rec), kaon identification (pid) and fitting procedure. The

uncertainty on the luminosity is 3.5%.

Systematic uncertainty [µb/MeV]

Bin [MeV] Signal [in units of 104_{] dσ/dp}

T[µb/MeV] rec pid Fitting

500 < pT,φ≤ 570 1.22 ± 0.07 0.44 ± 0.03 ± 0.03 ± 0.03 ± 0.07 570 < pT,φ≤ 640 2.34 ± 0.09 0.87 ± 0.04 ± 0.06 ± 0.05 ± 0.14 640 < pT,φ≤ 710 2.71 ± 0.10 1.01 ± 0.04 ± 0.06 ± 0.06 ± 0.16 710 < pT,φ≤ 780 3.19 ± 0.11 1.19 ± 0.04 ± 0.07 ± 0.09 ± 0.19 780 < pT,φ≤ 850 3.16 ± 0.11 1.18 ± 0.04 ± 0.06 ± 0.10 ± 0.19 850 < pT,φ≤ 920 2.85 ± 0.10 1.05 ± 0.04 ± 0.05 ± 0.09 ± 0.17 920 < pT,φ≤ 990 2.15 ± 0.09 0.79 ± 0.04 ± 0.03 ± 0.08 ± 0.15 990 < pT,φ≤ 1060 1.81 ± 0.07 0.67 ± 0.04 ± 0.03 ± 0.07 ± 0.13 1060 < pT,φ≤ 1130 1.30 ± 0.06 0.48 ± 0.04 ± 0.02 ± 0.05 ± 0.09 1130 < pT,φ≤ 1200 1.23 ± 0.08 0.46 ± 0.04 ± 0.02 ± 0.06 ± 0.09

Table 2: The fitted number of φ(1020) candidates (Signal), the differential production cross section dσ/d|y| [mb] of φ → K+_K− _{and its statistical uncertainty in bins of |y}

φ| with 500 < pT,φ< 1200 MeV,

|yφ| < 0.8, pT,K > 230 MeV and pK< 800 MeV and the systematic uncertainties due to track

reconstruc-tion efficiency (rec), kaon identification (pid) and fitting procedure. The uncertainty on the luminosity

is 3.5%.

Systematic uncertainty [mb]

Bin Signal [in units of 104_{] dσ/d|y| [mb] }

rec pid Fitting

0.0 < |yφ| ≤ 0.1 3.44 ± 0.10 0.90 ± 0.03 ± 0.04 ± 0.06 ± 0.21 0.1 < |yφ| ≤ 0.2 3.39 ± 0.10 0.88 ± 0.03 ± 0.04 ± 0.07 ± 0.20 0.2 < |yφ| ≤ 0.3 3.22 ± 0.09 0.84 ± 0.03 ± 0.04 ± 0.06 ± 0.19 0.3 < |yφ| ≤ 0.4 3.18 ± 0.09 0.82 ± 0.03 ± 0.04 ± 0.06 ± 0.19 0.4 < |yφ| ≤ 0.5 3.36 ± 0.11 0.88 ± 0.03 ± 0.05 ± 0.08 ± 0.20 0.5 < |yφ| ≤ 0.6 2.53 ± 0.12 0.66 ± 0.03 ± 0.04 ± 0.06 ± 0.18 0.6 < |yφ| ≤ 0.7 2.01 ± 0.11 0.51 ± 0.02 ± 0.03 ± 0.05 ± 0.14 0.7 < |yφ| ≤ 0.8 1.18 ± 0.07 0.30 ± 0.02 ± 0.02 ± 0.04 ± 0.08

decrease from |yφ| ≥ 0.5. This is due to the pK <

800 MeV requirement for efficient PID which ex-cludes an increasing fraction of kaons as the rapid-ity increases.

The cross section is best described by the PY-THIA 6 tune DW and by the EPOS-LHC tune. These provide a good description for the pT,φ and |yφ|

dependencies as well as for the total yield. The PYTHIA 6 MC09 tune slightly overestimates the data in the fiducial region. The PYTHIA 6 Perugia0 tune underestimates the cross section by around a fac-tor of two compared to the data in the whole fidu-cial volume. The two PYTHIA 8 A2 tunes, based on different PDFs, show similar predictions for the cross section, which are also about a factor of two too small. Herwig++ provides a good description for the cross section for pT,φ < 700 MeV and for

|yφ| > 0.6, but exhibits an overly steeply falling

pT,φdependence, such that the cross section is

un-derestimated for pT,φ> 700 MeV and in the

mid-rapidity range |yφ| < 0.6.

6 Extrapolated cross section

The kaon momenta requirements arising from track-ing and PID cuts (pT,K > 230 MeV and pK <

800 MeV) reject a significant number of φ → K+K− candidates. In order to allow comparison with other measurements, the cross section in the fiducial re-gion is extrapolated to a cross section in the kine-matic region 500 < pT,φ < 1200 MeV and

cen-tral rapidity |yφ| < 0.5, using MC particle level

information. The variation of the expected correc-tion between the different generators considered

[MeV] φ T, p 500 600 700 800 900 1000 1100 1200 b/MeV] µ [_T /dpφ σ d 0 0.5 1 1.5 2 2.5 3 3.5 ATLAS -1 b µ = 7 TeV, L = 383 s ATLAS ALICE

Fig. 5: The φ(1020)-meson cross section as a func-tion of pT,φ, extrapolated using PYTHIA 6 to the

kinematic region with 500 < pT,φ < 1200 MeV

and |yφ| < 0.5, is compared to the measurement

by the ALICE Collaboration [3]. The error bars represent the statistical uncertainty and the boxes represent the quadratic sum of the statistical and systematic uncertainties. The 3.5% uncertainty on the luminosity is not included.

is 10% and is included as an additional system-atic uncertainty on the extrapolated result. A cor-rection for the branching fraction is also applied. The systematic uncertainty on the branching frac-tion is 1% [27]. The extrapolafrac-tion is done with PYTHIA 6, because the cross section’s dependence on pT,φwithin the fiducial region is well described

by this generator, as shown in Fig. 4. The extrap-olation is restricted to |yφ| < 0.5, where the

fidu-cial acceptance is large, over 70%. The extrapo-lation factor is 2.78 for the lowest pT,φ bin, then

decreases to 1.08 at pT,φ∼ 900 MeV and becomes

1.21 in highest pT,φ bin.

The extrapolated cross section is compared to the measurement by the ALICE Collaboration of the φ(1020) production cross section as described in Ref. [3]. A comparison between the cross sec-tion measurements is shown in Fig. 5. The mea-surements as a function of pT,φ are in agreement

to within 10% in the first two bins and to within 3% in the other bins, which is well within the sys-tematic uncertainties.

7 Summary

This paper presents a measurement of the differ-ential production cross section of the φ(1020) me-son using the K+K−decay mode and 383 µb−1 of 7 TeV pp collision data collected with the ATLAS experiment at the LHC. To avoid model-dependent extrapolations outside the detector acceptance, the cross section is measured in a fiducial region, with

500 < pT,φ < 1200 MeV, |yφ| < 0.8, kaon pT,K >

230 MeV and kaon momentum pK < 800 MeV

re-quirements, which are determined by particle iden-tification and track reconstruction constraints.

The φ(1020) production cross section is in agree-ment with the predictions of the MC generator tunes EPOS-LHC and PYTHIA 6 DW. PYTHIA 6 pre-dictions using different tunes are observed to differ significantly. The cross section is also underesti-mated by PYTHIA 8 and by Herwig++. This mea-surement can provide useful input for tuning and development of phenomenological models in order to improve MC generators.

8 Acknowledgements

We thank CERN for the very successful operation of the LHC, as well as the support staff from our institutions without whom ATLAS could not be operated efficiently.

We acknowledge the support of ANPCyT, Ar-gentina; YerPhI, Armenia; ARC, Australia; BMWF and FWF, Austria; ANAS, Azerbaijan; SSTC, Be-larus; CNPq and FAPESP, Brazil; NSERC, NRC and CFI, Canada; CERN; CONICYT, Chile; CAS, MOST and NSFC, China; COLCIENCIAS, Colom-bia; MSMT CR, MPO CR and VSC CR, Czech Republic; DNRF, DNSRC and Lundbeck Founda-tion, Denmark; EPLANET, ERC and NSRF, Eu-ropean Union; IN2P3-CNRS, CEA-DSM/IRFU, France; GNSF, Georgia; BMBF, DFG, HGF, MPG and AvH Foundation, Germany; GSRT and NSRF, Greece; ISF, MINERVA, GIF, DIP and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; FOM and NWO, Netherlands; BRF and RCN, Norway; MNiSW, Poland; GRICES and FCT, Portugal; MNE/IFA, Romania; MES of Russia and ROSATOM, Russian Federation; JINR; MSTD, Serbia; MSSR, Slovakia; ARRS and MIZˇS, Slovenia; DST/NRF, South Africa; MICINN, Spain; SRC and Wallenberg Foundation, Sweden; SER, SNSF and Cantons of Bern and Geneva, Switzer-land; NSC, Taiwan; TAEK, Turkey; STFC, the Royal Society and Leverhulme Trust, United King-dom; DOE and NSF, United States of America.

The crucial computing support from all WLCG partners is acknowledged gratefully, in particular from CERN and the ATLAS Tier-1 facilities at TRIUMF (Canada), NDGF (Denmark, Norway, Sweden), CC-IN2P3 (France), KIT/GridKA (Ger-many), INFN-CNAF (Italy), NL-T1 (Netherlands), PIC

(Spain), ASGC (Taiwan), RAL (UK) and BNL (USA) and in the Tier-2 facilities worldwide.

References

1. ATLAS Collaboration, JINST 3 (2008) S08003, [arXiv:0901.0512[hep-ex]].

2. ATLAS Collaboration, ATLAS-CONF-2011-016, http://cds.cern.ch/record/1336519.

3. ALICE Collaboration, Eur. Phys. J. C 72 (2012) 2183, [arXiv:1208.5717[hep-ex]].

4. LHCb Collaboration, Phys. Lett. B 703 (2011) 267, [arXiv:1107.3935[hep-ex]].

5. ATLAS Collaboration, Eur. Phys. J. C 73 (2013) 2518, [arXiv:1302.4393[hep-ex]].

6. ATLAS Collaboration, New J. Phys. 13 (2011) 053033, [arXiv:1012.5104[hep-ex]].

7. ATLAS Collaboration, ATLAS-CONF-2010-069, http://cds.cern.ch/record/1281344.

8. T. Sj¨ostrand, S. Mrenna and P.Z. Skands, J. High Energy Phys. 0605 (2006) 026,

[arXiv:0603175[hep-ph]].

9. T. Sj¨ostrand, S. Mrenna and P.Z. Skands, Comput. Phys. Commun. 178 (2008) 852. 10. M. B¨ahr et al., Eur. Phys. J. C 58 (2008) 639,

[arXiv:0803.0883[hep-ph]].

11. K. Werner, F.-M.K Liu and T. Pierog, Phys. Rev. C 74 (2006) 044902, [arXiv:0506232[hep-ph]]. 12. K. Werner et al., Phys. Rev. C 82 (2010) 044904,

[arXiv:1004.0805[nucl-th]].

13. B. Andersson, G. Gustafson, G. Ingelman and T. Sj¨ostrand, Phys. Rept. 97 (1983) 31.

14. ATLAS Collaboration, ATL-PHYS-PUB-2010-002, http://cds.cern.ch/record/1247375.

15. M. Albrow et al. (TeV4 QCD Working Group), [arXiv:0610012[hep-ph]]. Femilab-Conf-06-359. 16. P.Z. Skands, Phys. Rev. D 82 (2010) 074018,

[arXiv:1005.3457[hep-ph]].

17. A.D. Martin, W.J. Stirling, R.S. Thorne and G. Watt, Eur. Phys. J. C 63 (2009) 189,

[arXiv:0901.0002[hep-ph]].

18. R. Corke and T. Sj¨ostrand, J. High Energy Phys. 1103 (2011) 032, [arXiv:1011.1759[hep-ph]]. 19. J. Pumplin et al., JHEP 0207 (2002) 012,

[arXiv:0201195[hep-ph]].

20. S. Gieseke, C.A. Rohr and A. Siodmok, [arXiv:1110.2675[hep-ph]]. MPI@LHC 2010 proceedings.

21. B.R. Webber, Nucl. Phys. B 238 (1984) 492. 22. T. Pierog et al., [arXiv:1306.0121[hep-ph]]. 23. H.J. Drescher et al., Phys. Rept. 350 (2001) 93,

[arXiv:0007198[hep-ph]].

24. ATLAS Collaboration, Eur. Phys. J. C. 70 (2010) 823, [arXiv:1005.4568[hep-ex]].

25. S. Agostinelli et al. (GEANT4 Collaboration), Nucl. Instrum. Meth. A 506 (2003) 250. 26. H. Bethe and J. Ashkin,. Ed. E. Segr´e, J. Wiley,

New York, 1953.

27. J. Beringer et al. (Particle Data Group), Phys. Rev. D 86 (2012) 010001.

The ATLAS Collaboration

G. Aad48, T. Abajyan21, B. Abbott111, J. Abdallah12, S. Abdel Khalek115, A.A. Abdelalim49, O. Abdinov11_{, R. Aben}105_{, B. Abi}112_{, M. Abolins}88_{, O.S. AbouZeid}158_{, H. Abramowicz}153_,

H. Abreu136_{, B.S. Acharya}164a,164b_{, L. Adamczyk}38_{, D.L. Adams}25_{, T.N. Addy}56_{, J. Adelman}176_,

S. Adomeit98, P. Adragna75, T. Adye129, S. Aefsky23, J.A. Aguilar-Saavedra124b,a, M. Agustoni17, M. Aharrouche81_{, S.P. Ahlen}22_{, F. Ahles}48_{, A. Ahmad}148_{, M. Ahsan}41_{, G. Aielli}133a,133b_,

T.P.A. ˚Akesson79_{, G. Akimoto}155_{, A.V. Akimov}94_{, M.S. Alam}2_{, M.A. Alam}76_{, J. Albert}169_,

S. Albrand55_{, M. Aleksa}30_{, I.N. Aleksandrov}64_{, F. Alessandria}89a_{, C. Alexa}26a_{, G. Alexander}153_,

G. Alexandre49, T. Alexopoulos10, M. Alhroob164a,164c, M. Aliev16, G. Alimonti89a, J. Alison120, B.M.M. Allbrooke18_{, P.P. Allport}73_{, S.E. Allwood-Spiers}53_{, J. Almond}82_{, A. Aloisio}102a,102b_,

R. Alon172_{, A. Alonso}79_{, F. Alonso}70_{, A. Altheimer}35_{, B. Alvarez Gonzalez}88_{, M.G. Alviggi}102a,102b_,

K. Amako65, C. Amelung23, V.V. Ammosov128,∗, S.P. Amor Dos Santos124a, A. Amorim124a,b, N. Amram153_{, C. Anastopoulos}30_{, L.S. Ancu}17_{, N. Andari}115_{, T. Andeen}35_{, C.F. Anders}58b_,

G. Anders58a_{, K.J. Anderson}31_{, A. Andreazza}89a,89b_{, V. Andrei}58a_{, M-L. Andrieux}55_{, X.S. Anduaga}70_,

S. Angelidakis9, P. Anger44, A. Angerami35, F. Anghinolfi30, A. Anisenkov107, N. Anjos124a, A. Annovi47_{, A. Antonaki}9_{, M. Antonelli}47_{, A. Antonov}96_{, J. Antos}144b_{, F. Anulli}132a_{, M. Aoki}101_,

S. Aoun83_{, L. Aperio Bella}5_{, R. Apolle}118,c_{, G. Arabidze}88_{, I. Aracena}143_{, Y. Arai}65_{, A.T.H. Arce}45_,

S. Arfaoui148, J-F. Arguin93, S. Argyropoulos42, E. Arik19a,∗, M. Arik19a, A.J. Armbruster87,

O. Arnaez81_{, V. Arnal}80_{, C. Arnault}115_{, A. Artamonov}95_{, G. Artoni}132a,132b_{, D. Arutinov}21_{, S. Asai}155_,

S. Ask28_{, B. ˚Asman}146a,146b_{, L. Asquith}6_{, K. Assamagan}25_{, A. Astbury}169_{, M. Atkinson}165_,

B. Aubert5, E. Auge115, K. Augsten127, M. Aurousseau145a, G. Avolio30, R. Avramidou10, D. Axen168, G. Azuelos93,d_{, Y. Azuma}155_{, M.A. Baak}30_{, G. Baccaglioni}89a_{, C. Bacci}134a,134b_{, A.M. Bach}15_,

H. Bachacou136_{, K. Bachas}30_{, M. Backes}49_{, M. Backhaus}21_{, J. Backus Mayes}143_{, E. Badescu}26a_,

P. Bagnaia132a,132b, S. Bahinipati3, Y. Bai33a, D.C. Bailey158, T. Bain158, J.T. Baines129,

O.K. Baker176_{, M.D. Baker}25_{, S. Baker}77_{, P. Balek}126_{, E. Banas}39_{, P. Banerjee}93_{, Sw. Banerjee}173_,

D. Banfi30_{, A. Bangert}150_{, V. Bansal}169_{, H.S. Bansil}18_{, L. Barak}172_{, S.P. Baranov}94_,

A. Barbaro Galtieri15, T. Barber48, E.L. Barberio86, D. Barberis50a,50b, M. Barbero21, D.Y. Bardin64, T. Barillari99_{, M. Barisonzi}175_{, T. Barklow}143_{, N. Barlow}28_{, B.M. Barnett}129_{, R.M. Barnett}15_,

A. Baroncelli134a_{, G. Barone}49_{, A.J. Barr}118_{, F. Barreiro}80_{, J. Barreiro Guimar˜aes da Costa}57_,

P. Barrillon115, R. Bartoldus143, A.E. Barton71, V. Bartsch149, A. Basye165, R.L. Bates53,

L. Batkova144a_{, J.R. Batley}28_{, A. Battaglia}17_{, M. Battistin}30_{, F. Bauer}136_{, H.S. Bawa}143,e_{, S. Beale}98_,

T. Beau78_{, P.H. Beauchemin}161_{, R. Beccherle}50a_{, P. Bechtle}21_{, H.P. Beck}17_{, A.K. Becker}175_,

S. Becker98_{, M. Beckingham}138_{, K.H. Becks}175_{, A.J. Beddall}19c_{, A. Beddall}19c_{, S. Bedikian}176_,

V.A. Bednyakov64, C.P. Bee83, L.J. Beemster105, M. Begel25, S. Behar Harpaz152, P.K. Behera62, M. Beimforde99_{, C. Belanger-Champagne}85_{, P.J. Bell}49_{, W.H. Bell}49_{, G. Bella}153_{, L. Bellagamba}20a_,

M. Bellomo30_{, A. Belloni}57_{, O. Beloborodova}107,f_{, K. Belotskiy}96_{, O. Beltramello}30_{, O. Benary}153_,

D. Benchekroun135a, K. Bendtz146a,146b, N. Benekos165, Y. Benhammou153, E. Benhar Noccioli49, J.A. Benitez Garcia159b_{, D.P. Benjamin}45_{, M. Benoit}115_{, J.R. Bensinger}23_{, K. Benslama}130_,

S. Bentvelsen105_{, D. Berge}30_{, E. Bergeaas Kuutmann}42_{, N. Berger}5_{, F. Berghaus}169_{, E. Berglund}105_,

J. Beringer15, P. Bernat77, R. Bernhard48, C. Bernius25, T. Berry76, C. Bertella83, A. Bertin20a,20b, F. Bertolucci122a,122b_{, M.I. Besana}89a,89b_{, G.J. Besjes}104_{, N. Besson}136_{, S. Bethke}99_{, W. Bhimji}46_,

R.M. Bianchi30_{, L. Bianchini}23_{, M. Bianco}72a,72b_{, O. Biebel}98_{, S.P. Bieniek}77_{, K. Bierwagen}54_,

J. Biesiada15, M. Biglietti134a, H. Bilokon47, M. Bindi20a,20b, S. Binet115, A. Bingul19c, C. Bini132a,132b, C. Biscarat178_{, B. Bittner}99_{, C.W. Black}150_{, K.M. Black}22_{, R.E. Blair}6_{, J.-B. Blanchard}136_,

G. Blanchot30_{, T. Blazek}144a_{, I. Bloch}42_{, C. Blocker}23_{, J. Blocki}39_{, A. Blondel}49_{, W. Blum}81_,

U. Blumenschein54, G.J. Bobbink105, V.B. Bobrovnikov107, S.S. Bocchetta79, A. Bocci45, C.R. Boddy118_{, M. Boehler}48_{, J. Boek}175_{, N. Boelaert}36_{, J.A. Bogaerts}30_{, A. Bogdanchikov}107_,

A. Bogouch90,∗_{, C. Bohm}146a_{, J. Bohm}125_{, V. Boisvert}76_{, T. Bold}38_{, V. Boldea}26a_{, N.M. Bolnet}136_,

M. Bomben78, M. Bona75, M. Boonekamp136, S. Bordoni78, C. Borer17, A. Borisov128, G. Borissov71, I. Borjanovic13a_{, M. Borri}82_{, S. Borroni}87_{, J. Bortfeldt}98_{, V. Bortolotto}134a,134b_{, K. Bos}105_,

D. Boscherini20a_{, M. Bosman}12_{, H. Boterenbrood}105_{, J. Bouchami}93_{, J. Boudreau}123_,

E.V. Bouhova-Thacker71, D. Boumediene34, C. Bourdarios115, N. Bousson83, A. Boveia31, J. Boyd30, I.R. Boyko64_{, I. Bozovic-Jelisavcic}13b_{, J. Bracinik}18_{, P. Branchini}134a_{, A. Brandt}8_{, G. Brandt}118_,

O. Brandt54_{, U. Bratzler}156_{, B. Brau}84_{, J.E. Brau}114_{, H.M. Braun}175,∗_{, S.F. Brazzale}164a,164c_,

B. Brelier158_{, J. Bremer}30_{, K. Brendlinger}120_{, R. Brenner}166_{, S. Bressler}172_{, D. Britton}53_,

F.M. Brochu28, I. Brock21, R. Brock88, F. Broggi89a, C. Bromberg88, J. Bronner99, G. Brooijmans35, T. Brooks76_{, W.K. Brooks}32b_{, G. Brown}82_{, H. Brown}8_{, P.A. Bruckman de Renstrom}39_{, D. Bruncko}144b_,

R. Bruneliere48_{, S. Brunet}60_{, A. Bruni}20a_{, G. Bruni}20a_{, M. Bruschi}20a_{, T. Buanes}14_{, Q. Buat}55_,

F. Bucci49, J. Buchanan118, P. Buchholz141, R.M. Buckingham118, A.G. Buckley46, S.I. Buda26a, I.A. Budagov64_{, B. Budick}108_{, V. B¨uscher}81_{, L. Bugge}117_{, O. Bulekov}96_{, A.C. Bundock}73_{, M. Bunse}43_,

T. Buran117_{, H. Burckhart}30_{, S. Burdin}73_{, T. Burgess}14_{, S. Burke}129_{, E. Busato}34_{, P. Bussey}53_,

C.P. Buszello166_{, B. Butler}143_{, J.M. Butler}22_{, C.M. Buttar}53_{, J.M. Butterworth}77_{, W. Buttinger}28_,

M. Byszewski30_{, S. Cabrera Urb´an}167_{, D. Caforio}20a,20b_{, O. Cakir}4a_{, P. Calafiura}15_{, G. Calderini}78_,

P. Calfayan98_{, R. Calkins}106_{, L.P. Caloba}24a_{, R. Caloi}132a,132b_{, D. Calvet}34_{, S. Calvet}34_,

R. Camacho Toro34_{, P. Camarri}133a,133b_{, D. Cameron}117_{, L.M. Caminada}15_{, R. Caminal Armadans}12_,

S. Campana30, M. Campanelli77, V. Canale102a,102b, F. Canelli31, A. Canepa159a, J. Cantero80, R. Cantrill76_{, L. Capasso}102a,102b_{, M.D.M. Capeans Garrido}30_{, I. Caprini}26a_{, M. Caprini}26a_,

D. Capriotti99_{, M. Capua}37a,37b_{, R. Caputo}81_{, R. Cardarelli}133a_{, T. Carli}30_{, G. Carlino}102a_,

L. Carminati89a,89b, B. Caron85, S. Caron104, E. Carquin32b, G.D. Carrillo-Montoya145b, A.A. Carter75, J.R. Carter28_{, J. Carvalho}124a,g_{, D. Casadei}108_{, M.P. Casado}12_{, M. Cascella}122a,122b_{, C. Caso}50a,50b,∗_,

A.M. Castaneda Hernandez173,h_{, E. Castaneda-Miranda}173_{, V. Castillo Gimenez}167_{, N.F. Castro}124a_,

G. Cataldi72a, P. Catastini57, A. Catinaccio30, J.R. Catmore30, A. Cattai30, G. Cattani133a,133b, S. Caughron88_{, V. Cavaliere}165_{, P. Cavalleri}78_{, D. Cavalli}89a_{, M. Cavalli-Sforza}12_{, V. Cavasinni}122a,122b_,

F. Ceradini134a,134b_{, A.S. Cerqueira}24b_{, A. Cerri}30_{, L. Cerrito}75_{, F. Cerutti}47_{, S.A. Cetin}19b_,

A. Chafaq135a, D. Chakraborty106, I. Chalupkova126, K. Chan3, P. Chang165, B. Chapleau85, J.D. Chapman28_{, J.W. Chapman}87_{, E. Chareyre}78_{, D.G. Charlton}18_{, V. Chavda}82_,

C.A. Chavez Barajas30_{, S. Cheatham}85_{, S. Chekanov}6_{, S.V. Chekulaev}159a_{, G.A. Chelkov}64_,

M.A. Chelstowska104, C. Chen63, H. Chen25, S. Chen33c, X. Chen173, Y. Chen35, Y. Cheng31, A. Cheplakov64_{, R. Cherkaoui El Moursli}135e_{, V. Chernyatin}25_{, E. Cheu}7_{, S.L. Cheung}158_,

L. Chevalier136_{, G. Chiefari}102a,102b_{, L. Chikovani}51a,∗_{, J.T. Childers}30_{, A. Chilingarov}71_,

G. Chiodini72a, A.S. Chisholm18, R.T. Chislett77, A. Chitan26a, M.V. Chizhov64, G. Choudalakis31, S. Chouridou137_{, I.A. Christidi}77_{, A. Christov}48_{, D. Chromek-Burckhart}30_{, M.L. Chu}151_{, J. Chudoba}125_,

G. Ciapetti132a,132b_{, A.K. Ciftci}4a_{, R. Ciftci}4a_{, D. Cinca}34_{, V. Cindro}74_{, C. Ciocca}20a,20b_{, A. Ciocio}15_,

M. Cirilli87, P. Cirkovic13b, Z.H. Citron172, M. Citterio89a, M. Ciubancan26a, A. Clark49, P.J. Clark46, R.N. Clarke15_{, W. Cleland}123_{, J.C. Clemens}83_{, B. Clement}55_{, C. Clement}146a,146b_{, Y. Coadou}83_,

M. Cobal164a,164c_{, A. Coccaro}138_{, J. Cochran}63_{, L. Coffey}23_{, J.G. Cogan}143_{, J. Coggeshall}165_,

E. Cogneras178_{, J. Colas}5_{, S. Cole}106_{, A.P. Colijn}105_{, N.J. Collins}18_{, C. Collins-Tooth}53_{, J. Collot}55_,

T. Colombo119a,119b_{, G. Colon}84_{, G. Compostella}99_{, P. Conde Mui˜no}124a_{, E. Coniavitis}166_,

M.C. Conidi12_{, S.M. Consonni}89a,89b_{, V. Consorti}48_{, S. Constantinescu}26a_{, C. Conta}119a,119b_,

G. Conti57_{, F. Conventi}102a,i_{, M. Cooke}15_{, B.D. Cooper}77_{, A.M. Cooper-Sarkar}118_{, K. Copic}15_,

T. Cornelissen175, M. Corradi20a, F. Corriveau85,j, A. Cortes-Gonzalez165, G. Cortiana99, G. Costa89a, M.J. Costa167_{, D. Costanzo}139_{, D. Cˆot´e}30_{, L. Courneyea}169_{, G. Cowan}76_{, C. Cowden}28_{, B.E. Cox}82_,

K. Cranmer108_{, F. Crescioli}122a,122b_{, M. Cristinziani}21_{, G. Crosetti}37a,37b_{, S. Cr´ep´e-Renaudin}55_,

C.-M. Cuciuc26a, C. Cuenca Almenar176, T. Cuhadar Donszelmann139, J. Cummings176, M. Curatolo47, C.J. Curtis18_{, C. Cuthbert}150_{, P. Cwetanski}60_{, H. Czirr}141_{, P. Czodrowski}44_{, Z. Czyczula}176_,

S. D’Auria53_{, M. D’Onofrio}73_{, A. D’Orazio}132a,132b_{, M.J. Da Cunha Sargedas De Sousa}124a_,

C. Da Via82, W. Dabrowski38, A. Dafinca118, T. Dai87, C. Dallapiccola84, M. Dam36, M. Dameri50a,50b, D.S. Damiani137_{, H.O. Danielsson}30_{, V. Dao}49_{, G. Darbo}50a_{, G.L. Darlea}26b_{, J.A. Dassoulas}42_,

W. Davey21_{, T. Davidek}126_{, N. Davidson}86_{, R. Davidson}71_{, E. Davies}118,c_{, M. Davies}93_{, O. Davignon}78_,

A.R. Davison77, Y. Davygora58a, E. Dawe142, I. Dawson139, R.K. Daya-Ishmukhametova23, K. De8, R. de Asmundis102a_{, S. De Castro}20a,20b_{, S. De Cecco}78_{, J. de Graat}98_{, N. De Groot}104_{, P. de Jong}105_,

C. De La Taille115_{, H. De la Torre}80_{, F. De Lorenzi}63_{, L. de Mora}71_{, L. De Nooij}105_{, D. De Pedis}132a_,

A. De Salvo132a, U. De Sanctis164a,164c, A. De Santo149, J.B. De Vivie De Regie115, G. De Zorzi132a,132b_{, W.J. Dearnaley}71_{, R. Debbe}25_{, C. Debenedetti}46_{, B. Dechenaux}55_,

D.V. Dedovich64_{, J. Degenhardt}120_{, J. Del Peso}80_{, T. Del Prete}122a,122b_{, T. Delemontex}55_,

M. Delmastro5_{, P.A. Delsart}55_{, C. Deluca}105_{, S. Demers}176_{, M. Demichev}64_{, B. Demirkoz}12,k_,

S.P. Denisov128_{, D. Derendarz}39_{, J.E. Derkaoui}135d_{, F. Derue}78_{, P. Dervan}73_{, K. Desch}21_,

E. Devetak148, P.O. Deviveiros105, A. Dewhurst129, B. DeWilde148, S. Dhaliwal158, R. Dhullipudi25,l, A. Di Ciaccio133a,133b_{, L. Di Ciaccio}5_{, C. Di Donato}102a,102b_{, A. Di Girolamo}30_{, B. Di Girolamo}30_,

S. Di Luise134a,134b_{, A. Di Mattia}173_{, B. Di Micco}30_{, R. Di Nardo}47_{, A. Di Simone}133a,133b_,

R. Di Sipio20a,20b, M.A. Diaz32a, E.B. Diehl87, J. Dietrich42, T.A. Dietzsch58a, S. Diglio86,

K. Dindar Yagci40_{, J. Dingfelder}21_{, F. Dinut}26a_{, C. Dionisi}132a,132b_{, P. Dita}26a_{, S. Dita}26a_{, F. Dittus}30_,

F. Djama83_{, T. Djobava}51b_{, M.A.B. do Vale}24c_{, A. Do Valle Wemans}124a,m_{, T.K.O. Doan}5_,

M. Dobbs85_{, D. Dobos}30_{, E. Dobson}30,n_{, J. Dodd}35_{, C. Doglioni}49_{, T. Doherty}53_{, Y. Doi}65,∗_,

J. Dolejsi126_{, I. Dolenc}74_{, Z. Dolezal}126_{, B.A. Dolgoshein}96,∗_{, T. Dohmae}155_{, M. Donadelli}24d_,

J. Donini34_{, J. Dopke}30_{, A. Doria}102a_{, A. Dos Anjos}173_{, A. Dotti}122a,122b_{, M.T. Dova}70_,

A.D. Doxiadis105_{, A.T. Doyle}53_{, N. Dressnandt}120_{, M. Dris}10_{, J. Dubbert}99_{, S. Dube}15_{, E. Duchovni}172_,

G. Duckeck98, D. Duda175, A. Dudarev30, F. Dudziak63, M. D¨uhrssen30, I.P. Duerdoth82, L. Duflot115, M-A. Dufour85_{, L. Duguid}76_{, M. Dunford}58a_{, H. Duran Yildiz}4a_{, R. Duxfield}139_{, M. Dwuznik}38_,

M. D¨uren52_{, W.L. Ebenstein}45_{, J. Ebke}98_{, S. Eckweiler}81_{, K. Edmonds}81_{, W. Edson}2_{, C.A. Edwards}76_,

N.C. Edwards53, W. Ehrenfeld42, T. Eifert143, G. Eigen14, K. Einsweiler15, E. Eisenhandler75, T. Ekelof166_{, M. El Kacimi}135c_{, M. Ellert}166_{, S. Elles}5_{, F. Ellinghaus}81_{, K. Ellis}75_{, N. Ellis}30_,

J. Elmsheuser98_{, M. Elsing}30_{, D. Emeliyanov}129_{, R. Engelmann}148_{, A. Engl}98_{, B. Epp}61_{, J. Erdmann}54_,

A. Ereditato17, D. Eriksson146a, J. Ernst2, M. Ernst25, J. Ernwein136, D. Errede165, S. Errede165, E. Ertel81_{, M. Escalier}115_{, H. Esch}43_{, C. Escobar}123_{, X. Espinal Curull}12_{, B. Esposito}47_{, F. Etienne}83_,

A.I. Etienvre136_{, E. Etzion}153_{, D. Evangelakou}54_{, H. Evans}60_{, L. Fabbri}20a,20b_{, C. Fabre}30_,

R.M. Fakhrutdinov128, S. Falciano132a, Y. Fang173, M. Fanti89a,89b, A. Farbin8, A. Farilla134a, J. Farley148_{, T. Farooque}158_{, S. Farrell}163_{, S.M. Farrington}170_{, P. Farthouat}30_{, F. Fassi}167_,

P. Fassnacht30_{, D. Fassouliotis}9_{, B. Fatholahzadeh}158_{, A. Favareto}89a,89b_{, L. Fayard}115_{, S. Fazio}37a,37b_,

R. Febbraro34, P. Federic144a, O.L. Fedin121, W. Fedorko88, M. Fehling-Kaschek48, L. Feligioni83, C. Feng33d_{, E.J. Feng}6_{, A.B. Fenyuk}128_{, J. Ferencei}144b_{, W. Fernando}6_{, S. Ferrag}53_{, J. Ferrando}53_,

V. Ferrara42_{, A. Ferrari}166_{, P. Ferrari}105_{, R. Ferrari}119a_{, D.E. Ferreira de Lima}53_{, A. Ferrer}167_,

D. Ferrere49, C. Ferretti87, A. Ferretto Parodi50a,50b, M. Fiascaris31, F. Fiedler81, A. Filipˇciˇc74, F. Filthaut104_{, M. Fincke-Keeler}169_{, M.C.N. Fiolhais}124a,g_{, L. Fiorini}167_{, A. Firan}40_{, G. Fischer}42_,

M.J. Fisher109_{, M. Flechl}48_{, I. Fleck}141_{, J. Fleckner}81_{, P. Fleischmann}174_{, S. Fleischmann}175_,

T. Flick175, A. Floderus79, L.R. Flores Castillo173, M.J. Flowerdew99, T. Fonseca Martin17, A. Formica136_{, A. Forti}82_{, D. Fortin}159a_{, D. Fournier}115_{, A.J. Fowler}45_{, H. Fox}71_{, P. Francavilla}12_,

M. Franchini20a,20b_{, S. Franchino}119a,119b_{, D. Francis}30_{, T. Frank}172_{, M. Franklin}57_{, S. Franz}30_,

M. Fraternali119a,119b_{, S. Fratina}120_{, S.T. French}28_{, C. Friedrich}42_{, F. Friedrich}44_{, R. Froeschl}30_,

D. Froidevaux30_{, J.A. Frost}28_{, C. Fukunaga}156_{, E. Fullana Torregrosa}30_{, B.G. Fulsom}143_{, J. Fuster}167_,

C. Gabaldon30_{, O. Gabizon}172_{, T. Gadfort}25_{, S. Gadomski}49_{, G. Gagliardi}50a,50b_{, P. Gagnon}60_,

C. Galea98_{, B. Galhardo}124a_{, E.J. Gallas}118_{, V. Gallo}17_{, B.J. Gallop}129_{, P. Gallus}125_{, K.K. Gan}109_,

Y.S. Gao143,e, A. Gaponenko15, F. Garberson176, M. Garcia-Sciveres15, C. Garc´ıa167,

J.E. Garc´ıa Navarro167_{, R.W. Gardner}31_{, N. Garelli}30_{, H. Garitaonandia}105_{, V. Garonne}30_{, C. Gatti}47_,

G. Gaudio119a_{, B. Gaur}141_{, L. Gauthier}136_{, P. Gauzzi}132a,132b_{, I.L. Gavrilenko}94_{, C. Gay}168_,

G. Gaycken21, E.N. Gazis10, P. Ge33d, Z. Gecse168, C.N.P. Gee129, D.A.A. Geerts105, Ch. Geich-Gimbel21_{, K. Gellerstedt}146a,146b_{, C. Gemme}50a_{, A. Gemmell}53_{, M.H. Genest}55_,

S. Gentile132a,132b_{, M. George}54_{, S. George}76_{, P. Gerlach}175_{, A. Gershon}153_{, C. Geweniger}58a_,

H. Ghazlane135b, N. Ghodbane34, B. Giacobbe20a, S. Giagu132a,132b, V. Giakoumopoulou9, V. Giangiobbe12_{, F. Gianotti}30_{, B. Gibbard}25_{, A. Gibson}158_{, S.M. Gibson}30_{, M. Gilchriese}15_,

D. Gillberg29_{, A.R. Gillman}129_{, D.M. Gingrich}3,d_{, J. Ginzburg}153_{, N. Giokaris}9_{, M.P. Giordani}164c_,

R. Giordano102a,102b, F.M. Giorgi16, P. Giovannini99, P.F. Giraud136, D. Giugni89a, M. Giunta93, B.K. Gjelsten117_{, L.K. Gladilin}97_{, C. Glasman}80_{, J. Glatzer}21_{, A. Glazov}42_{, K.W. Glitza}175_,

G.L. Glonti64_{, J.R. Goddard}75_{, J. Godfrey}142_{, J. Godlewski}30_{, M. Goebel}42_{, T. G¨opfert}44_,

C. Goeringer81, C. G¨ossling43, S. Goldfarb87, T. Golling176, A. Gomes124a,b, L.S. Gomez Fajardo42, R. Gon¸calo76_{, J. Goncalves Pinto Firmino Da Costa}42_{, L. Gonella}21_{, S. Gonz´alez de la Hoz}167_,

G. Gonzalez Parra12_{, M.L. Gonzalez Silva}27_{, S. Gonzalez-Sevilla}49_{, J.J. Goodson}148_{, L. Goossens}30_,

A. Goriˇsek74_{, E. Gornicki}39_{, A.T. Goshaw}6_{, M. Gosselink}105_{, M.I. Gostkin}64_{, I. Gough Eschrich}163_,

M. Gouighri135a_{, D. Goujdami}135c_{, M.P. Goulette}49_{, A.G. Goussiou}138_{, C. Goy}5_{, S. Gozpinar}23_,

I. Grabowska-Bold38, P. Grafstr¨om20a,20b, K-J. Grahn42, E. Gramstad117, F. Grancagnolo72a, S. Grancagnolo16_{, V. Grassi}148_{, V. Gratchev}121_{, N. Grau}35_{, H.M. Gray}30_{, J.A. Gray}148_,

E. Graziani134a_{, O.G. Grebenyuk}121_{, T. Greenshaw}73_{, Z.D. Greenwood}25,l_{, K. Gregersen}36_,

I.M. Gregor42, P. Grenier143, J. Griffiths8, N. Grigalashvili64, A.A. Grillo137, S. Grinstein12, Ph. Gris34, Y.V. Grishkevich97_{, J.-F. Grivaz}115_{, E. Gross}172_{, J. Grosse-Knetter}54_{, J. Groth-Jensen}172_,

K. Grybel141_{, D. Guest}176_{, C. Guicheney}34_{, E. Guido}50a,50b_{, S. Guindon}54_{, U. Gul}53_{, J. Gunther}125_,

B. Guo158_{, J. Guo}35_{, P. Gutierrez}111_{, N. Guttman}153_{, O. Gutzwiller}173_{, C. Guyot}136_{, C. Gwenlan}118_,

C.B. Gwilliam73_{, A. Haas}108_{, S. Haas}30_{, C. Haber}15_{, H.K. Hadavand}8_{, D.R. Hadley}18_{, P. Haefner}21_,

F. Hahn30_{, Z. Hajduk}39_{, H. Hakobyan}177_{, D. Hall}118_{, K. Hamacher}175_{, P. Hamal}113_{, K. Hamano}86_,

M. Hamer54_{, A. Hamilton}145b,o_{, S. Hamilton}161_{, L. Han}33b_{, K. Hanagaki}116_{, K. Hanawa}160_,

M. Hance15, C. Handel81, P. Hanke58a, J.R. Hansen36, J.B. Hansen36, J.D. Hansen36, P.H. Hansen36, P. Hansson143_{, K. Hara}160_{, T. Harenberg}175_{, S. Harkusha}90_{, D. Harper}87_{, R.D. Harrington}46_,

O.M. Harris138_{, J. Hartert}48_{, F. Hartjes}105_{, T. Haruyama}65_{, A. Harvey}56_{, S. Hasegawa}101_,

Y. Hasegawa140, S. Hassani136, S. Haug17, M. Hauschild30, R. Hauser88, M. Havranek21,

C.M. Hawkes18_{, R.J. Hawkings}30_{, A.D. Hawkins}79_{, T. Hayakawa}66_{, T. Hayashi}160_{, D. Hayden}76_,

C.P. Hays118_{, H.S. Hayward}73_{, S.J. Haywood}129_{, S.J. Head}18_{, V. Hedberg}79_{, L. Heelan}8_{, S. Heim}120_,

B. Heinemann15, S. Heisterkamp36, L. Helary22, C. Heller98, M. Heller30, S. Hellman146a,146b, D. Hellmich21_{, C. Helsens}12_{, R.C.W. Henderson}71_{, M. Henke}58a_{, A. Henrichs}176_,

A.M. Henriques Correia30_{, S. Henrot-Versille}115_{, C. Hensel}54_{, T. Henß}175_{, C.M. Hernandez}8_,

Y. Hern´andez Jim´enez167, R. Herrberg16, G. Herten48, R. Hertenberger98, L. Hervas30, G.G. Hesketh77, N.P. Hessey105_{, E. Hig´on-Rodriguez}167_{, J.C. Hill}28_{, K.H. Hiller}42_{, S. Hillert}21_{, S.J. Hillier}18_,

I. Hinchliffe15_{, E. Hines}120_{, M. Hirose}116_{, F. Hirsch}43_{, D. Hirschbuehl}175_{, J. Hobbs}148_{, N. Hod}153_,

M.C. Hodgkinson139, P. Hodgson139, A. Hoecker30, M.R. Hoeferkamp103, J. Hoffman40, D. Hoffmann83, M. Hohlfeld81_{, M. Holder}141_{, S.O. Holmgren}146a_{, T. Holy}127_{, J.L. Holzbauer}88_{, T.M. Hong}120_,

L. Hooft van Huysduynen108_{, S. Horner}48_{, J-Y. Hostachy}55_{, S. Hou}151_{, A. Hoummada}135a_,

J. Howard118, J. Howarth82, I. Hristova16, J. Hrivnac115, T. Hryn’ova5, P.J. Hsu81, S.-C. Hsu15, D. Hu35_{, Z. Hubacek}127_{, F. Hubaut}83_{, F. Huegging}21_{, A. Huettmann}42_{, T.B. Huffman}118_,

E.W. Hughes35_{, G. Hughes}71_{, M. Huhtinen}30_{, M. Hurwitz}15_{, N. Huseynov}64,p_{, J. Huston}88_{, J. Huth}57_,

G. Iacobucci49, G. Iakovidis10, M. Ibbotson82, I. Ibragimov141, L. Iconomidou-Fayard115, J. Idarraga115, P. Iengo102a_{, O. Igonkina}105_{, Y. Ikegami}65_{, M. Ikeno}65_{, D. Iliadis}154_{, N. Ilic}158_{, T. Ince}99_{, P. Ioannou}9_,

M. Iodice134a_{, K. Iordanidou}9_{, V. Ippolito}132a,132b_{, A. Irles Quiles}167_{, C. Isaksson}166_{, M. Ishino}67_,

M. Ishitsuka157_{, R. Ishmukhametov}109_{, C. Issever}118_{, S. Istin}19a_{, A.V. Ivashin}128_{, W. Iwanski}39_,

H. Iwasaki65_{, J.M. Izen}41_{, V. Izzo}102a_{, B. Jackson}120_{, J.N. Jackson}73_{, P. Jackson}1_{, M.R. Jaekel}30_,

V. Jain60_{, K. Jakobs}48_{, S. Jakobsen}36_{, T. Jakoubek}125_{, J. Jakubek}127_{, D.O. Jamin}151_{, D.K. Jana}111_,

E. Jansen77_{, H. Jansen}30_{, J. Janssen}21_{, A. Jantsch}99_{, M. Janus}48_{, R.C. Jared}173_{, G. Jarlskog}79_,

L. Jeanty57, I. Jen-La Plante31, D. Jennens86, P. Jenni30, A.E. Loevschall-Jensen36, P. Jeˇz36,

S. J´ez´equel5_{, M.K. Jha}20a_{, H. Ji}173_{, W. Ji}81_{, J. Jia}148_{, Y. Jiang}33b_{, M. Jimenez Belenguer}42_{, S. Jin}33a_,

O. Jinnouchi157_{, M.D. Joergensen}36_{, D. Joffe}40_{, M. Johansen}146a,146b_{, K.E. Johansson}146a_,

P. Johansson139, S. Johnert42, K.A. Johns7, K. Jon-And146a,146b, G. Jones170, R.W.L. Jones71, T.J. Jones73_{, C. Joram}30_{, P.M. Jorge}124a_{, K.D. Joshi}82_{, J. Jovicevic}147_{, T. Jovin}13b_{, X. Ju}173_,

C.A. Jung43_{, R.M. Jungst}30_{, V. Juranek}125_{, P. Jussel}61_{, A. Juste Rozas}12_{, S. Kabana}17_{, M. Kaci}167_,

A. Kaczmarska39, P. Kadlecik36, M. Kado115, H. Kagan109, M. Kagan57, E. Kajomovitz152,

S. Kalinin175_{, L.V. Kalinovskaya}64_{, S. Kama}40_{, N. Kanaya}155_{, M. Kaneda}30_{, S. Kaneti}28_{, T. Kanno}157_,

V.A. Kantserov96_{, J. Kanzaki}65_{, B. Kaplan}108_{, A. Kapliy}31_{, J. Kaplon}30_{, D. Kar}53_{, M. Karagounis}21_,

K. Karakostas10, M. Karnevskiy42, V. Kartvelishvili71, A.N. Karyukhin128, L. Kashif173,

G. Kasieczka58b_{, R.D. Kass}109_{, A. Kastanas}14_{, M. Kataoka}5_{, Y. Kataoka}155_{, E. Katsoufis}10_{, J. Katzy}42_,

V. Kaushik7_{, K. Kawagoe}69_{, T. Kawamoto}155_{, G. Kawamura}81_{, M.S. Kayl}105_{, S. Kazama}155_,

V.A. Kazanin107, M.Y. Kazarinov64, R. Keeler169, P.T. Keener120, R. Kehoe40, M. Keil54, G.D. Kekelidze64_{, J.S. Keller}138_{, M. Kenyon}53_{, O. Kepka}125_{, N. Kerschen}30_{, B.P. Kerˇsevan}74_,

S. Kersten175_{, K. Kessoku}155_{, J. Keung}158_{, F. Khalil-zada}11_{, H. Khandanyan}146a,146b_{, A. Khanov}112_,