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High-$E_{\rm T}$ isolated-photon plus jets production in $pp$ collisions at $\sqrt s=$ 8 TeV with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
Nucl.Phys. B918 (2017) 257-316, 2017.
Inspire Record 1499475 DOI 10.17182/hepdata.79948

The dynamics of isolated-photon plus one-, two- and three-jet production in pp collisions at a centre-of-mass energy of 8 TeV are studied with the ATLAS detector at the LHC using a data set with an integrated luminosity of 20.2 fb−1 . Measurements of isolated-photon plus jets cross sections are presented as functions of the photon and jet transverse momenta. The cross sections as functions of the azimuthal angle between the photon and the jets, the azimuthal angle between the jets, the photon–jet invariant mass and the scattering angle in the photon–jet centre-of-mass system are presented. The pattern of QCD radiation around the photon and the leading jet is investigated by measuring jet production in an annular region centred on each object; enhancements are observed around the leading jet with respect to the photon in the directions towards the beams. The experimental measurements are compared to several different theoretical calculations, and overall a good description of the data is found.

35 data tables

Measured cross sections for isolated-photon plus 1jet production as a function of $E_{\rm T}^{\gamma}$.

Measured cross sections for isolated-photon plus 1jet production as a function of $p_{\rm T}^{\rm jet1}$.

Measured cross sections for isolated-photon plus 1jet production as a function of $m^{\gamma-\rm jet1}$.

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Measurement of the $b\overline{b}$ dijet cross section in $pp$ collisions at $\sqrt{s} = 7$ TeV with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
No Journal Information, 2016.
Inspire Record 1478355 DOI 10.17182/hepdata.75316

The dijet production cross section for jets containing a $b$-hadron ($b$-jets) has been measured in proton-proton collisions with a centre-of-mass energy of $\sqrt{s} = 7$ TeV, using the ATLAS detector at the LHC. The data used correspond to an integrated luminosity of 4.2 fb$^{-1}$. The cross section is measured for events with two identified $b$-jets with a transverse momentum $p_T > 20$ GeV and a minimum separation in the $\eta$-$\phi$ plane of $\Delta R = 0.4$. At least one of the jets in the event is required to have $p_T > 270$ GeV. The cross section is measured differentially as a function of dijet invariant mass, dijet transverse momentum, boost of the dijet system, and the rapidity difference, azimuthal angle and angular distance between the $b$-jets. The results are compared to different predictions of leading order and next-to-leading order perturbative quantum chromodynamics matrix elements supplemented with models for parton-showers and hadronization.

6 data tables

Results for the m_bb distribution. Statistical and systematic uncertainties are quoted.

Results for the DeltaPhi distribution. Statistical and systematic uncertainties are quoted.

Results for the y* distribution. Statistical and systematic uncertainties are quoted.

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Production of exclusive dijets in diffractive deep inelastic scattering at HERA

The ZEUS collaboration Abramowicz, H. ; Abt, I. ; Adamczyk, L. ; et al.
Eur.Phys.J. C76 (2016) 16, 2016.
Inspire Record 1372086 DOI 10.17182/hepdata.73738

Production of exclusive dijets in diffractive deep inelastic $e^\pm p$ scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 372 pb$^{-1}$. The measurement was performed for $\gamma^*-p$ centre-of-mass energies in the range $90 < W < 250$ GeV and for photon virtualities $Q^2 > 25$ GeV$^2$. Energy and transverse-energy flows around the jet axis are presented. The cross section is presented as a function of $\beta$ and $\phi$, where $\beta=x/x_{\rm I\!P}$, $x$ is the Bjorken variable and $x_{\rm I\!P}$ is the proton fractional longitudinal momentum loss. The angle $\phi$ is defined by the $\gamma^*-$dijet plane and the $\gamma^*-e^\pm$ plane in the rest frame of the diffractive final state. The $\phi$ cross section is measured in bins of $\beta$. The results are compared to predictions from models based on different assumptions about the nature of the diffractive exchange.

3 data tables

Differential cross-section $d\sigma/d\beta$ in the kinematic range: $Q^2 > 25 GeV^2$, $90 < W < 250 GeV^2$, $x_{\rm I\!P} < 0.01$, $M_X > 5 GeV$ and $p_{T,jet} > 2 GeV$. The contribution from proton dissociation was subtracted. The uncertainty of the subtraction determines the uncertainty of the normalisation also given in the table.

Differential cross-section $d\sigma/d\phi$ in the kinematic range: $Q^2 > 25 GeV^2$, $90 < W < 250 GeV$, $x_{\rm I\!P} < 0.01$, $M_X > 5 GeV$ and $p_{T,jet} > 2 GeV$. The contribution from proton dissociation was subtracted. The uncertainty of the subtraction determines the uncertainty of the normalisation given in the table.

Results of the fit to the cross-section $d\sigma/d\phi$ in bins of $\beta$. The fitted function is proportional to $(1+A \rm{cos}2\phi)$. The uncertainty includes both statistical and systematical contributions (see text of paper).


Measurement of forward $\rm Z\rightarrow e^+e^-$ production at $\sqrt{s}=8$ TeV

The LHCb collaboration Aaij, Roel ; Adeva, Bernardo ; Adinolfi, Marco ; et al.
JHEP 1505 (2015) 109, 2015.
Inspire Record 1347133 DOI 10.17182/hepdata.73305

A measurement of the cross-section for Z-boson production in the forward region of pp collisions at 8 TeV centre-of-mass energy is presented. The measurement is based on a sample of Z → e$^{+}$e$^{−}$ decays reconstructed using the LHCb detector, corresponding to an integrated luminosity of 2.0 fb$^{−1}$. The acceptance is defined by the requirements 2.0 < η < 4.5 and p$_{T}$ > 20 GeV for the pseudorapidities and transverse momenta of the leptons. Their invariant mass is required to lie in the range 60-120 GeV. The cross-section is determined to be $ \sigma \left(\mathrm{pp}\to \mathrm{Z}\to {\mathrm{e}}^{+}{\mathrm{e}}^{-}\right)=93.81\pm 0.41\left(\mathrm{stat}\right)\pm 1.48\left(\mathrm{syst}\right)\pm 1.14\left(\mathrm{lumi}\right)\mathrm{p}\mathrm{b}, $ where the first uncertainty is statistical and the second reflects all systematic effects apart from that arising from the luminosity, which is given as the third uncertainty. Differential cross-sections are presented as functions of the Z-boson rapidity and of the angular variable ϕ$^{∗}$, which is related to the Z-boson transverse momentum.

3 data tables

Integrated cross-section for Z$\to$ e$^+$e$^-$ within the LHCb acceptance.

Differential cross-section for Z$\to$ e$^+$e$^-$ as a function of Z-boson rapidity. The first error is statistical, the second the uncorrelated experimental systematic, the third the correlated experimental systematic and the last error is the uncertainty in luminosity. The cross-sections are at the Born level, i.e. before FSR. The rightmost column gives values of the additional factor, $f_{\rm FSR}$, by which the results should be multiplied in order to give the cross-sections after FSR.

Differential cross-section for Z$\to$ e$^+$e$^-$ as a function of $\phi^*$. The first error is statistical, the second the uncorrelated experimental systematic, the third the correlated experimental systematic and the last error is the uncertainty in luminosity. The cross-sections are at the Born level, i.e. before FSR. The rightmost column gives values of the additional factor, $f_{\rm FSR}$, by which the results should be multiplied in order to give the cross-sections after FSR.


Measurement of forward W and Z boson production in $pp$ collisions at $ \sqrt{s}=8 $ TeV

The LHCb collaboration Aaij, Roel ; Abellán Beteta, Carlos ; Adeva, Bernardo ; et al.
JHEP 1601 (2016) 155, 2016.
Inspire Record 1406555 DOI 10.17182/hepdata.71419

Measurements are presented of electroweak boson production using data from pp collisions at a centre-of-mass energy of $ \sqrt{s}=8 $ TeV. The analysis is based on an integrated luminosity of 2.0 fb$^{−1}$ recorded with the LHCb detector. The bosons are identified in the W → μν and Z → μ$^{+}$ μ$^{−}$ decay channels. The cross-sections are measured for muons in the pseudorapidity range 2.0 < η < 4.5, with transverse momenta p$_{T}$ > 20 GeV/c and, in the case of the Z boson, a dimuon mass within $ 60 < {M}_{\mu }{{{}_{{}^{+}}}_{\mu}}_{{}^{-}}<120 $ GeV/c$^{2}$. The results are $ {\sigma}_W{{}_{{}^{+}}}_{\to \mu }{{}_{{}^{+}}}_{\nu }=1093.6\pm 2.1\pm 7.2\pm 10.9\pm 12.7\ \mathrm{p}\mathrm{b}, $ $ {\sigma}_W{{}_{{}^{-}}}_{\to \mu }{{}_{{}^{-}}}_{\overline{\nu}}=818.4\pm 1.9\pm 5.0\pm 7.0\pm 9.5\ \mathrm{p}\mathrm{b}, $ $ {\sigma}_{\mathrm{Z}\to \mu }{{{}_{{}^{+}}}_{\mu}}_{{}^{-}}=95.0\pm 0.3\pm 0.7\pm 1.1\pm 1.1\ \mathrm{p}\mathrm{b}, $ $ {\sigma}_{Z\to \mu }{{{}_{{}^{+}}}_{\mu}}_{{}^{-}}=95.0\pm 0.3\pm 0.7\pm 1.1\pm 1.1\ \mathrm{p}\mathrm{b}, $ where the first uncertainties are statistical, the second are systematic, the third are due to the knowledge of the LHC beam energy and the fourth are due to the luminosity determination. The evolution of the W and Z boson cross-sections with centre-of-mass energy is studied using previously reported measurements with 1.0 fb$^{−1}$ of data at 7 TeV. Differential distributions are also presented. Results are in good agreement with theoretical predictions at next-to-next-to-leading order in perturbative quantum chromodynamics.

23 data tables

Inclusive cross-section for $W^+$ and $W^-$ boson production in bins of muon pseudorapidity. The uncertainties are statistical, systematic, beam and luminosity.

Inclusive cross-section for $Z$ boson production in bins of rapidity. The uncertainties are statistical, systematic, beam and luminosity.

Inclusive cross-section for $Z$ boson production in bins of transverse momentum. The uncertainties are statistical, systematic, beam and luminosity.

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Measurement of the forward $Z$ boson production cross-section in $pp$ collisions at $\sqrt{s}=7$ TeV

The LHCb collaboration Aaij, Roel ; Adeva, Bernardo ; Adinolfi, Marco ; et al.
JHEP 1508 (2015) 039, 2015.
Inspire Record 1373300 DOI 10.17182/hepdata.2114

A measurement of the production cross-section for Z bosons that decay to muons is presented. The data were recorded by the LHCb detector during pp collisions at a centre-of-mass energy of 7 TeV, and correspond to an integrated luminosity of 1.0 fb$^{−1}$. The cross-section is measured for muons in the pseudorapidity range 2.0 < η < 4.5 with transverse momenta p$_{T}$ > 20 GeV/c. The dimuon mass is restricted to 60 < M$_{μ}$ +$_{μ}$ − < 120 GeV/c$^{2}$. The measured cross-section is $ {\sigma}_{Z\to \mu }{+}_{\mu }-=\left(76.0\pm 0.3\pm 0.5\pm 1.0\pm 1.3\right)\mathrm{p}\mathrm{b} $

11 data tables

Inclusive cross-section for $Z$ boson production in bins of rapidity. The uncertainties are statistical, systematic, beam and luminosity.

Inclusive cross-section for $Z$ boson production in bins of transverse momentum. The uncertainties are statistical, systematic, beam and luminosity.

Inclusive cross-section for $Z$ boson production in bins of PHI*. The uncertainties are statistical, systematic, beam and luminosity.

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Further studies of the photoproduction of isolated photons with a jet at HERA

The ZEUS collaboration Abramowicz, H. ; Abt, I. ; Adamczyk, L. ; et al.
JHEP 1408 (2014) 023, 2014.
Inspire Record 1298390 DOI 10.17182/hepdata.64205

In this extended analysis using the ZEUS detector at HERA, the photoproduction of isolated photons together with a jet is measured for different ranges of the fractional photon energy, $x_\gamma^{\mathrm{meas}}$, contributing to the photon-jet final state. Cross sections are evaluated in the photon transverse-energy and pseudorapidity ranges $6 < E_T^{\gamma} < 15$ GeV and $-0.7 < \eta^{\gamma} < 0.9$, and for jet transverse-energy and pseudorapidity ranges $4 < E_T^{\rm jet} < 35$ GeV and $-1.5 < \eta^{\rm jet} < 1.8$, for an integrated luminosity of 374 $\mathrm{pb}^{-1}$. The kinematic observables studied comprise the transverse energy and pseudorapidity of the photon and the jet, the azimuthal difference between them, the fraction of proton energy taking part in the interaction, and the difference between the pseudorapidities of the photon and the jet. Higher-order theoretical calculations are compared to the results.

7 data tables

Differential cross-section D(SIG)/DET(GAMMA) for photons in the given X(GAMMA) range accompanied by a jet. The corresponding hadronisation corrections are also given.

Differential cross-section D(SIG)/DETARAP(GAMMA) for photons in the given X(GAMMA) range accompanied by a jet. The corresponding hadronisation corrections are also given.

Differential cross-section D(SIG)/DET(JET) for photons in the given X(GAMMA) range accompanied by a jet. The corresponding hadronisation corrections are also given.

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Observation of double charm production involving open charm in pp collisions at $\sqrt{s}$ = 7 TeV

The LHCb collaboration Aaij, R ; Abellan Beteta, C ; Adeva, B ; et al.
JHEP 1206 (2012) 141, 2012.
Inspire Record 1113596 DOI 10.17182/hepdata.66915

The production of $J/\psi$ mesons accompanied by open charm, and of pairs of open charm hadrons are observed in pp collisions at a centre-of-mass energy of 7 TeV using an integrated luminosity of $355pb^{-1}$ collected with the LHCb detector. Model independent measurements of absolute cross-sections are given together with ratios to the measured $J/\psi$ and open charm cross-sections. The properties of these events are studied and compared to theoretical predictions.

52 data tables

Normalized differential cross-section $d\ln\sigma(pp\rightarrow J/\psi D^0 X)/dp_T(J/\psi)$ for $2<y(J/\psi)<4$, $p_T(J/\psi)<12$ GeV/$c$, $2<y(D^0)<4$, $3<p_T(D^0)<12$ GeV/$c$ region.

Normalized differential cross-section $d\ln\sigma(pp\rightarrow J/\psi D^+ X)/dp_T(J/\psi)$ for $2<y(J/\psi)<4$, $p_T(J/\psi)<12$ GeV/$c$, $2<y(D^+)<4$, $3<p_T(D^+)<12$ GeV/$c$ region.

Normalized differential cross-section $d\ln\sigma(pp\rightarrow J/\psi D_s^+ X)/dp_T(J/\psi)$ for $2<y(J/\psi)<4$, $p_T(J/\psi)<12$ GeV/$c$, $2<y(D_s^+)<4$, $3<p_T(D_s^+)<12$ GeV/$c$ region.

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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.

4 data tables

The D0 D*- pair cross section as a function of DELTA(PHI) in bins of trigger side D0 pT.

The D+ D*- pair cross section as a function of DELTA(PHI) in bins of trigger side D+ pT.

The D0 D*- pair cross section as a function of DELTA(PHI).

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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
4 data tables

Values of D(SIG)/DM(GAMMA GAMMA) for the data. The error given on each value is the total uncertainty.

Values of D(SIG)/DPT(GAMMA GAMMA) for the data. The error given on each value is the total uncertainty.

Values of D(SIG)/DDELTA(PHI(GAMMA GAMMA)) (pb/rad) for the data. The error given on each value is the total uncertainty.

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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.

10 data tables

The measured differential distribution in the two-photon mass;.

The measured differential distribution in the two-photon transverse momentum;.

The measured differential distribution in the azimuthal angular separation of the two photons;.

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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.

6 data tables

Diphoton production cross section as a function of the diphoton invariant mass.

Diphoton production cross section as a function of the diphoton transverse momentum.

Diphoton production cross section as a function of the azimuthal angle difference in the two photons.

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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.

5 data tables

Integrated diphoton cross sections.

Measured diphoton differential cross sections as a function of the diphoton mass for the two pseusdorapidity ranges.

Measured diphoton differential cross sections as a function of the diphoton transverse momentum for the two pseusdorapidity ranges.

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Photoproduction of pi0 eta on protons and the Delta(1700)D(33) resonance

The Crystal Ball at MAMI TAPS A2 collaborations Kashevarov, V.L. ; Fix, A. ; Aguar-Bartolome, P. ; et al.
Eur.Phys.J. A42 (2009) 141-149, 2009.
Inspire Record 811783 DOI 10.17182/hepdata.52974
5 data tables

Total cross section for the GAMMA P --> PI0 ETA P reaction.. Statistical erros only.

The differential cross section as a function of cos(theta(pi0) in the canonical(K) reference frame.. Statistical erros only.

The differential cross section as a function of phi(pi0) in the canonical(K) reference frame.. Statistical erros only.

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Deep inelastic scattering with leading protons or large rapidity gaps at HERA

The ZEUS collaboration Chekanov, S. ; Derrick, M. ; Magill, S. ; et al.
Nucl.Phys. B816 (2009) 1-61, 2009.
Inspire Record 804915 DOI 10.17182/hepdata.52860

The dissociation of virtual photons, $\gamma^{\star} p \to X p$, in events with a large rapidity gap between $X$ and the outgoing proton, as well as in events in which the leading proton was directly measured, has been studied with the ZEUS detector at HERA. The data cover photon virtualities $Q^2>2$ GeV$^2$ and $\gamma^{\star} p$ centre-of-mass energies $40&lt;W&lt;240$ GeV, with $M_X>2$ GeV, where $M_X$ is the mass of the hadronic final state, $X$. Leading protons were detected in the ZEUS leading proton spectrometer. The cross section is presented as a function of $t$, the squared four-momentum transfer at the proton vertex and $\Phi$, the azimuthal angle between the positron scattering plane and the proton scattering plane. It is also shown as a function of $Q^2$ and $\xpom$, the fraction of the proton's momentum carried by the diffractive exchange, as well as $\beta$, the Bjorken variable defined with respect to the diffractive exchange.

48 data tables

The differential cross section DSIG/DT for the LRG and the LPS data samples.

The fitted exponential slope of the T distribution as a function of X(NAME=POMERON).

The fitted exponential slope of the T distribution as a function of X(NAME=POMERON).

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Three- and Four-jet Production at Low x at HERA

The H1 collaboration Aaron, F.D. ; Aktas, A. ; Alexa, C. ; et al.
Eur.Phys.J. C54 (2008) 389-409, 2008.
Inspire Record 767896 DOI 10.17182/hepdata.45429

Three- and four-jet production is measured in deep-inelastic $ep$ scattering at low $x$ and $Q^2$ with the H1 detector using an integrated luminosity of $44{.}2 {\rm pb}^{-1}$. Several phase space regions are selected for the three-jet analysis in order to study the underlying parton dynamics from global topologies to the more restrictive regions of forward jets close to the proton direction. The measurements of cross sections for events with at least three jets are compared to fixed order QCD predictions of ${\mathcal{O}}(\alpha_{\rm s}^2)$ and ${\mathcal{O}}(\alpha_{\rm s}^3) $ and with Monte Carlo simulation programs where higher order effects are approximated by parton showers. A good overall description is provided by the ${\mathcal{O}}(\alpha_{\rm s}^3) $ calculation. Too few events are predicted at the lowest $x \sim 10^{-4}$, especially for topologies with two forward jets. This hints to large contributions at low $x$ from initial state radiation of gluons close to the proton direction and unordered in transverse momentum. The Monte Carlo program in which gluon radiation is generated by the colour dipole model gives a good description of both the three- and the four-jet data in absolute normalisation and shape.

23 data tables

Differential cross section as a function of the minimum number of jet for events with at least 3-jets.

Differential cross section as a function of X for events with at least 3-jets.

Differential cross section for events with at least 3-jets as a function of the pseudorapidity of each jet.

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Single-Pion Production in pp Collisions at 0.95-GeV/c. II.

The COSY-TOF collaboration Abd El-Samad, S. ; Bilger, R. ; Brinkmann, K.-Th. ; et al.
Eur.Phys.J. A39 (2009) 281-289, 2009.
Inspire Record 790164 DOI 10.17182/hepdata.50496

The single-pion production reactions $pp\to d\pi^+$, $pp\to np\pi^+$ and $pp\to pp\pi^0$ were measured at a beam momentum of 0.95 GeV/c ($T_p \approx$ 400 MeV) using the short version of the COSY-TOF spectrometer. The central calorimeter provided particle identification, energy determination and neutron detection in addition to time-of-flight and angle measurements from other detector parts. Thus all pion production channels were recorded with 1-4 overconstraints. Main emphasis is put on the presentation and discussion of the $np\pi^+$ channel, since the results on the other channels have already been published previously. The total and differential cross sections obtained are compared to theoretical calculations. In contrast to the $pp\pi^0$ channel we find in the $np\pi^+$ channel a strong influence of the $\Delta$ excitation already at this energy close to threshold. In particular we find a $(3 cos^2\Theta + 1)$ dependence in the pion angular distribution, typical for a pure s-channel $\Delta$ excitation and identical to that observed in the $d\pi^+$ channel. Since the latter is understood by a s-channel resonance in the $^1D_2$ $pn$ partial wave, we discuss an analogous scenario for the $pn\pi^+$ channel.

6 data tables

Differential cross section for the process P P --> P N PI+ as a function ofthe P PI+ mass.

Differential cross section for the process P P --> P N PI+ as a function ofthe N PI+ mass.

Differential cross section for the process P P --> P N PI+ as a function ofthe P N mass.

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High-E(T) dijet photoproduction at HERA

The ZEUS collaboration Chekanov, S. ; Derrick, M. ; Magill, S. ; et al.
Phys.Rev. D76 (2007) 072011, 2007.
Inspire Record 753991 DOI 10.17182/hepdata.45426

The cross section for high-E_T dijet production in photoproduction has been measured with the ZEUS detector at HERA using an integrated luminosity of 81.8 pb-1. The events were required to have a virtuality of the incoming photon, Q^2, of less than 1 GeV^2 and a photon-proton centre-of-mass energy in the range 142 < W < 293 GeV. Events were selected if at least two jets satisfied the transverse-energy requirements of E_T(jet1) > 20 GeV and E_T(jet2) > 15 GeV and pseudorapidity requirements of -1 < eta(jet1,2) < 3, with at least one of the jets satisfying -1 < eta(jet) < 2.5. The measurements show sensitivity to the parton distributions in the photon and proton and effects beyond next-to-leading order in QCD. Hence these data can be used to constrain further the parton densities in the proton and photon.

19 data tables

Cross section D(SIG)/(ET(P=4)+ET(P=5))/2 as a function of (ET(P=4)+ET(P=5))/2 for X(C=GAMMA,OBS) > 0.75 .

Cross section D(SIG)/(ET(P=4)+ET(P=5))/2 as a function of (ET(P=4)+ET(P=5))/2 for X(C=GAMMA,OBS) <= 0.75 .

Cross section D(SIG)/ET(P=4) as a function of ET(P=4) for X(C=GAMMA,OBS) > 0.75 .

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Diffractive photoproduction of rho mesons with large momentum transfer at HERA

The H1 collaboration Aktas, A. ; Andreev, V. ; Anthonis, T. ; et al.
Phys.Lett. B638 (2006) 422-431, 2006.
Inspire Record 712738 DOI 10.17182/hepdata.45698

The diffractive photoproduction of rho mesons, e p \to e rho Y, with large momentum transfer squared at the proton vertex, |t|, is studied with the H1 detector at HERA using an integrated luminosity of 20.1 pb^{-1}. The photon-proton centre of mass energy spans the range 75 &lt; W &lt; 95 GeV, the photon virtuality is restricted to Q^2 &lt; 0.01 GeV^2 and the mass M_Y of the proton remnant is below 5 GeV. The t dependence of the cross section is measured for the range 1.5 &lt; |t| &lt; 10.0 GeV^2 and is well described by a power law, dsigma/ d|t| \propto |t|^{-n}. The spin density matrix elements, which provide information on the helicity structure of the interaction, are extracted using measurements of angular distributions of the rho decay products. The data indicate a violation of s-channel helicity conservation, with contributions from both single and double helicity-flip being observed. The results are compared to the predictions of perturbative QCD models.

5 data tables

The normalized differential cross section as a function of T.

Normalised decay angular distribution w.r.t. the polar angle THETA.

Normalised decay angular distribution w.r.t. the polar angle THETA.

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Inclusive jet cross sections and dijet correlations in D*+- photoproduction at HERA

The ZEUS collaboration Chekanov, S. ; Derrick, M. ; Magill, S. ; et al.
Nucl.Phys. B729 (2005) 492-525, 2005.
Inspire Record 687943 DOI 10.17182/hepdata.46048

Inclusive jet cross sections in photoproduction for events containing a $D^*$ meson have been measured with the ZEUS detector at HERA using an integrated luminosity of $78.6 {\rm pb}^{-1}$. The events were required to have a virtuality of the incoming photon, $Q^2$, of less than 1 GeV$^2$, and a photon-proton centre-of-mass energy in the range $130&lt;W_{\gamma p}&lt;280 {\rm GeV}$. The measurements are compared with next-to-leading-order (NLO) QCD calculations. Good agreement is found with the NLO calculations over most of the measured kinematic region. Requiring a second jet in the event allowed a more detailed comparison with QCD calculations. The measured dijet cross sections are also compared to Monte Carlo (MC) models which incorporate leading-order matrix elements followed by parton showers and hadronisation. The NLO QCD predictions are in general agreement with the data although differences have been isolated to regions where contributions from higher orders are expected to be significant. The MC models give a better description than the NLO predictions of the shape of the measured cross sections.

29 data tables

Cross section as a function of the jet transverse energy for INCLUSIVE events containing at least one D* meson in different jet pseudorapidity regions.

Cross section as a function of the jet transverse energy for INCLUSIVE events containing at least one D* meson in different jet pseudorapidity regions.

Cross section as a function of the jet transverse energy for INCLUSIVE events containing at least one D* meson in different jet pseudorapidity regions.

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Study of hadronic final states from double tagged gamma gamma events at LEP

The ALEPH collaboration Heister, A. ; Schael, S. ; Barate, R. ; et al.
No Journal Information, 2003.
Inspire Record 619958 DOI 10.17182/hepdata.49702

The interaction of virtual photons is investigated using double tagged gammagamma events with hadronic final states recorded by the ALEPH experiment at e^+e^- centre-of-mass energies between 188 and 209 GeV. The measured cross section is compared to Monte Carlo models, and to next-to-leading-order QCD and BFKL calculations.

10 data tables

Differential cross section as a function of the relative energy of the scattered electrons.

Differential cross section as a function of the polar angle THETA of the scattered electrons.

Differential cross section as a function of the virtuality Q**2 of the photons.

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Study of the azimuthal asymmetry of jets in neutral current deep inelastic scattering at HERA

The ZEUS collaboration Chekanov, S. ; Krakauer, D. ; Magill, S. ; et al.
Phys.Lett. B551 (2003) 226-240, 2003.
Inspire Record 600814 DOI 10.17182/hepdata.46545

The azimuthal distribution of jets produced in the Breit frame in high-Q**2 deep inelastic e+p scattering has been studied with the ZEUS detector at HERA using an integrated luminosity of 38.6 pb-1. The measured azimuthal distribution shows a structure that is well described by next-to-leading-order QCD predictions over the Q**2 range considered, Q**2>125 GeV**2.

4 data tables

The normalised differential cross section as a function of azimuthal angle for inclusive jet production in the Breit frame.

The folded normalised differential cross section as a function of azimuthalangle for inclusive jet production in the Breit frame.

The folded normalised differential cross section as a function of azimuthalangle for inclusive jet production in the Breit frame.

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Measurement of the hadronic cross-section for the scattering of two virtual photons at LEP

The OPAL collaboration
Eur.Phys.J. C24 (2002) 17-31, 2002.
Inspire Record 563730 DOI 10.17182/hepdata.48895

The interaction of virtual photons is investigated using the reaction e+e- -> e+e- hadrons based on data taken by the OPAL experiment at e+e- centre-of-mass energies sqrt(s_ee)=189-209 GeV, for W>5 GeV and at an average Q^2 of 17.9 GeV^2. The measured cross-sections are compared to predictions of the Quark Parton Model (QPM), to the Leading Order QCD Monte Carlo model PHOJET to the NLO prediction for the reaction e+e- -> e+e-qqbar, and to BFKL calculations. PHOJET, NLO e+e- -> e+e-qqbar, and QPM describe the data reasonably well, whereas the cross-section predicted by a Leading Order BFKL calculation is too large.

11 data tables

Total cross section in the given phase space and assuming ALPHA = 1/137.

Differential cross section as a function of X where X is the maximum value of X1 or X2, the upper and lower vertex values.

Differential cross section as a function of Q**2 where Q**2 is the maximum value of Q1**2 or Q2**2, the upper and lower vertex values.

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Exclusive photoproduction of J / psi mesons at HERA

The ZEUS collaboration Chekanov, S. ; Krakauer, D. ; Magill, S. ; et al.
Eur.Phys.J. C24 (2002) 345-360, 2002.
Inspire Record 582237 DOI 10.17182/hepdata.46713

The exclusive photoproduction of J/psi mesons, gamma p->J/psi p, has been studied in ep collisions with the ZEUS detector at HERA, in the kinematic range 20<W<290 GeV, where W is the photon-proton centre-of-mass energy. The J/psi mesons were reconstructed in the muon and the electron decay channels using integrated luminosities of 38 pb^-1 and 55 pb^-1, respectively. The helicity structure of J/psi production shows that the hypothesis of s-channel helicity conservation is satisfied at the two standard-deviation level. The total cross section and the differential cross-section dsigma/dt, where t is the squared four-momentum transfer at the proton vertex, are presented as a function of W, for |t|<1.8 GeV^2. The t distribution exhibits an exponential shape with a slope parameter increasing logarithmically with W with a value b=4.15 \pm 0.05 (stat.)^{+0.30}_{-0.18} (syst.) GeV^-2 at W=90 GeV. The effective parameters of the Pomeron trajectory are alphapom(0) = 1.200 \pm 0.009(stat.)^{+0.004}_{-0.010}(syst.) and alphappom= 0.115 \pm 0.018(stat.)^{+0.008}_{-0.015}(syst.) GeV^-2.

12 data tables

The total exclusive J/PSI photoproduction cross section, the differential cross section extrapolated to t=0 and the slope parameter of the exponential t dependence as afunction of W, the photon-proton c.m. energy, for data from J/PSI muon decay.

The total exclusive J/PSI photoproduction cross section as a function of W,the photon-proton c.m. energy, for data from J/PSI electron decays.

The differential cross section extrapolated to t=0 and the slope parameter of the exponential t dependence for exclusive J/PSI photoproduction as a function of W, the photon-proton c.m. energy for data from J/PSI electron decays.

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pi+ --> pi+ pi+- on deuterium at T(pi+) = 283-MeV

The CHAOS collaboration Bonutti, F. ; Camerini, P. ; Fragiacomo, E. ; et al.
Nucl.Phys. A638 (1998) 729-746, 1998.
Inspire Record 480316 DOI 10.17182/hepdata.36186
2 data tables

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