Date

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First Measurement of the Underlying Event Activity at the LHC with $\sqrt{s} = 0.9$ TeV

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M. ; Tumasyan, Armen ; et al.
Eur.Phys.J. C70 (2010) 555-572, 2010.
Inspire Record 857644 DOI 10.17182/hepdata.55126

A measurement of the underlying activity in scattering processes with transverse momentum scale in the GeV region is performed in proton-proton collisions at sqrt(s) = 0.9 TeV, using data collected by the CMS experiment at the LHC. Charged hadron production is studied with reference to the direction of a leading object, either a charged particle or a set of charged particles forming a jet. Predictions of several QCD-inspired models as implemented in PYTHIA are compared, after full detector simulation, to the data. The models generally predict too little production of charged hadrons with pseudorapidity eta < 2, p_T > 0.5 GeV/c, and azimuthal direction transverse to that of the leading object.

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Measurement of the Cross Section for Prompt Isolated Diphoton Production in $p\bar{p}$ Collisions at $\sqrt{s} = 1.96$ TeV

The CDF collaboration Aaltonen, T. ; Alvarez Gonzalez, B. ; Amerio, S. ; et al.
Phys.Rev. D84 (2011) 052006, 2011.
Inspire Record 915978 DOI 10.17182/hepdata.60557

This article reports a measurement of the production cross section of prompt isolated photon pairs in proton-antiproton collisions at \sqrt{s} = 1.96 TeV using the CDF II detector at the Fermilab Tevatron collider. The data correspond to an integrated luminosity of 5.36/fb. The cross section is presented as a function of kinematic variables sensitive to the reaction mechanisms. The results are compared with three perturbative QCD calculations: (1) a leading order parton shower Monte Carlo, (2) a fixed next-to-leading order calculation and (3) a next-to-leading order/next-to-next-to-leading-log resummed calculation. The comparisons show that, within their known limitations, all calculations predict the main features of the data, but no calculation adequately describes all aspects of the data.

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Azimuthal decorrelations and multiple parton interactions in $\gamma$+2 jet and $\gamma$+3 jet events in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV

The D0 collaboration Abazov, Victor Mukhamedovich ; Abbott, Braden Keim ; Acharya, Bannanje Sripath ; et al.
Phys.Rev. D83 (2011) 052008, 2011.
Inspire Record 883664 DOI 10.17182/hepdata.63845
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Measurement of differential cross sections for the production of a pair of isolated photons in pp collisions at $\sqrt{s}=7\,\text {TeV} $

The CMS collaboration Chatrchyan, Serguei ; Khachatryan, Vardan ; Sirunyan, Albert M ; et al.
Eur.Phys.J. C74 (2014) 3129, 2014.
Inspire Record 1298393 DOI 10.17182/hepdata.64241
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Study of the energy dependence of the underlying event in proton-antiproton collisions

The CDF collaboration Aaltonen, Timo Antero ; Amerio, Silvia ; Amidei, Dante E ; et al.
Phys.Rev. D92 (2015) 092009, 2015.
Inspire Record 1388868 DOI 10.17182/hepdata.70787

We study charged particle production (pT>0.5  GeV/c, |η|<0.8) in proton-antiproton collisions at total center-of-mass energies s=300  GeV, 900 GeV, and 1.96 TeV. We use the direction of the charged particle with the largest transverse momentum in each event to define three regions of η-ϕ space: “toward”, “away”, and “transverse.” The average number and the average scalar pT sum of charged particles in the transverse region are sensitive to the modeling of the “underlying event.” The transverse region is divided into a MAX and MIN transverse region, which helps separate the “hard component” (initial and final-state radiation) from the “beam-beam remnant” and multiple parton interaction components of the scattering. The center-of-mass energy dependence of the various components of the event is studied in detail. The data presented here can be used to constrain and improve QCD Monte Carlo models, resulting in more precise predictions at the LHC energies of 13 and 14 TeV.

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Measurement of dijet azimuthal decorrelation in pp collisions at $\sqrt{s}=8\,\mathrm{TeV} $

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Eur.Phys.J. C76 (2016) 536, 2016.
Inspire Record 1421646 DOI 10.17182/hepdata.74207
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Polarization of Muoproduced J/psi (3100)

Clark, A.R. ; Johnson, K.J. ; Kerth, L.T. ; et al.
Phys.Rev.Lett. 45 (1980) 2092, 1980.
Inspire Record 155741 DOI 10.17182/hepdata.20697
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$\psi$ production and $\bar{p} N$ and $\pi^- N$ interactions at 125-GeV/c and a determination of the gluon structure functions of the $\bar{p}$ and the $\pi^-$

Tzamarias, S. ; Katsanevas, S. ; Kourkoumelis, C. ; et al.
Phys.Rev. D48 (1993) 5067-5080, 1993.
Inspire Record 297586 DOI 10.17182/hepdata.22578
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Charm production studies at CDF

The CDF collaboration Reisert, B. ; Lewis, J. ; Liu, T. ; et al.
Nucl.Phys.Proc.Suppl. 170 (2007) 243-247, 2007.
Inspire Record 766572 DOI 10.17182/hepdata.65519

The upgraded Collider Detector at Fermilab (CDF II) has a high bandwidth available for track based triggers. This capability in conjunction with the unprecedented integrated luminosity in excess of 1 fb −1 enables detailed studies of charm hadron production. CDF is now releasing first measurements of the prompt charm meson pair cross sections, which give access to QCD mechanisms by which charm quarks are produced in proton anti-proton collisions. Recent results on the spin alignment of J/ψ and ψ(2S) as well as on the relative production of the χc1(P1) and χc2(1P) challenge our understanding of the fragmentation of charm quarks into charmonium states.

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Measurement of the differential cross sections for isolated direct photon pair production in $p \bar p$ collisions at $\sqrt{s} = 1.96$ TeV

The D0 collaboration Abazov, V.M. ; Abbott, Braden Keim ; Acharya, Bannanje Sripath ; et al.
Phys.Lett. B725 (2013) 6-14, 2013.
Inspire Record 1215307 DOI 10.17182/hepdata.60556

We present measurements of direct photon pair production cross sections using 8.5 fb$^{-1}$ of data collected with the D0 detector at the Fermilab Tevatron $p \bar p$ collider. The results are presented as differential distributions of the photon pair invariant mass $d\sigma/dM_{\gamma \gamma}$, pair transverse momentum $d \sigma /dp^{\gamma \gamma}_T$, azimuthal angle between the photons $d\sigma/d\Delta \phi_{\gamma \gamma}$, and polar scattering angle in the Collins-Soper frame $d\sigma /d|\cos \theta^*|$. Measurements are performed for isolated photons with transverse momenta $p^{\gamma}_T>18 ~(17)$ GeV for the leading (next-to-leading) photon in $p_T$, pseudorapidities $|\eta^{\gamma}|<0.9$, and a separation in $\eta-\phi$ space $\Delta\mathcal R_{\gamma\gamma} > 0.4$. We present comparisons with the predictions from Monte Carlo event generators {\sc diphox} and {\sc resbos} implementing QCD calculations at next-to-leading order, $2\gamma${\sc nnlo} at next-to-next-to-leading order, and {\sc sherpa} using matrix elements with higher-order real emissions matched to parton shower.

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Angular coefficients of Z bosons produced in pp collisions at $\sqrt{s}$ = 8 TeV and decaying to $\mu^+ \mu^-$ as a function of transverse momentum and rapidity

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Phys.Lett. B750 (2015) 154-175, 2015.
Inspire Record 1359451 DOI 10.17182/hepdata.69285

Measurements of the five most significant angular coefficients, A[0] through A[4], for Z bosons produced in pp collisions at $\sqrt{s}$ = 8 TeV and decaying to $\mu^+ \mu^-$ are presented as a function of the transverse momentum and rapidity of Z boson. The integrated luminosity of the dataset collected with the CMS detector at the LHC corresponds to 19.7 inverse femtobarns. These measurements provide comprehensive information about Z boson production mechanisms, and are compared to QCD predictions at leading order, next-to-leading order, and next-to-next-to-leading order in perturbation theory.

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Measurement of the Production Cross Section for Pairs of Isolated Photons in $pp$ collisions at $\sqrt{s}=7$ TeV

The CMS collaboration Chatrchyan, Serguei ; Khachatryan, Vardan ; Sirunyan, Albert M ; et al.
JHEP 1201 (2012) 133, 2012.
Inspire Record 943720 DOI 10.17182/hepdata.58959

The integrated and differential cross sections for the production of pairs of isolated photons is measured in proton-proton collisions at a centre-of-mass energy of 7 TeV with the CMS detector at the LHC. A data sample corresponding to an integrated luminosity of 36 inverse picobarns is analysed. A next-to-leading-order perturbative QCD calculation is compared to the measurements. A discrepancy is observed for regions of the phase space where the two photons have an azimuthal angle difference, $\Delta(\phi)$, less than approximately 2.8.

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