Diffractive Dijet Photoproduction in ep Collisions at HERA

The H1 collaboration Aaron, F.D. ; Alexa, C. ; Andreev, V. ; et al.
Eur.Phys.J.C 70 (2010) 15-37, 2010.
Inspire Record 857109 DOI 10.17182/hepdata.61487

Measurements are presented of single and double-differential dijet cross sections in diffractive photoproduction based on a data sample with an integrated luminosity of 47 pb^-1. The events are of the type ep -> eXY, where the hadronic system X contains at least two jets and is separated by a large rapidity gap from the system Y, which consists of a leading proton or low-mass proton excitation. The dijet cross sections are compared with QCD calculations at next-to-leading order and with a Monte Carlo model based on leading order matrix elements with parton showers. The measured cross sections are smaller than those obtained from the next-to-leading order calculations by a factor of about 0.6. This suppression factor has no significant dependence on the fraction x_gamma of the photon four-momentum entering the hard subprocess. Ratios of the diffractive to the inclusive dijet cross sections are measured for the first time and are compared with Monte Carlo models.

18 data tables

Total diffractive dijet positron-proton cross section integrated over the full measured kinematic range.

Bin averaged hadron level differential cross section for diffractive dijet production as a function of X(C=GAMMA). The first systematic error is the uncorrelated and the second the correlated uncertainty.

Bin averaged hadron level differential cross section for diffractive dijet production as a function of the ET of jet 1. The first systematic error is the uncorrelated and the second the correlated uncertainty.

More…

Diffractive Dijet Production with a Leading Proton in $ep$ Collisions at HERA

The H1 collaboration Andreev, V. ; Baghdasaryan, A. ; Begzsuren, K. ; et al.
JHEP 05 (2015) 056, 2015.
Inspire Record 1343110 DOI 10.17182/hepdata.73234

The cross section of the diffractive process e^+p -> e^+Xp is measured at a centre-of-mass energy of 318 GeV, where the system X contains at least two jets and the leading final state proton p is detected in the H1 Very Forward Proton Spectrometer. The measurement is performed in photoproduction with photon virtualities Q^2 <2 GeV^2 and in deep-inelastic scattering with 4 GeV^2<Q^2<80 GeV^2. The results are compared to next-to-leading order QCD calculations based on diffractive parton distribution functions as extracted from measurements of inclusive cross sections in diffractive deep-inelastic scattering.

23 data tables

Integrated $e^{+}p$ diffractive dijet cross sections in $\gamma p$. The hadronisation correction factor ($1+\delta_{\text{hadr}}$) applied to the NLO calculation is also listed. The overall normalisation uncertainty of $6\%$ is not included in the table.

Integrated $e^{+}p$ diffractive dijet cross sections in DIS. The hadronisation correction factor ($1+\delta_{\text{hadr}}$) applied to the NLO calculation and the radiative correction ($1+\delta_{\text{rad}}$) are also listed. The overall normalisation uncertainty of $6\%$ is not included in the table.

Ratio of integrated $e^{+}p$ diffractive dijet cross sections for $Q^2<2\,\text{GeV}^2$ (photoproduction) to $Q^2>4\,\text{GeV}^2$ (DIS).

More…

Dijet production in charged and neutral current e+ p interactions at high Q**2.

The H1 collaboration Adloff, C. ; Andreev, V. ; Andrieu, B. ; et al.
Eur.Phys.J.C 19 (2001) 429-440, 2001.
Inspire Record 534736 DOI 10.17182/hepdata.46947

Jet production in charged and neutral current events in the kinematic range of Q^2 from 640 to 35000 GeV^2 is studied in deep-inelastic positron-proton scattering at HERA. The measured rate of multi-jet events and distributions of jet polar angle, transverse energy, dijet mass, and other dijet variables are presented. Using parton densities derived from inclusive DIS cross sections, perturbative QCD calculations in NLO are found to give a consistent description of both the neutral and charged current dijet production. A direct, model independent comparison of the jet distributions in charged and neutral current events confirms that the QCD dynamics of the hadronic final state is independent of the underlying electroweak scattering process.

9 data tables

Rates of charged current events as a function of Q**2.

Rates of neutral current events as a function of Q**2.

Normalised distribution in Y2 for NC and CC dijet events. Y2 is the smallest scaled value of KT (KTJET**2/W**2) given by the combination of (2+1) jets. The +1 refers to the proton remnant jet.

More…

Energy flow and rapidity gaps between jets in photoproduction at HERA

The H1 collaboration Adloff, C. ; Andreev, V. ; Andrieu, B. ; et al.
Eur.Phys.J.C 24 (2002) 517-527, 2002.
Inspire Record 583863 DOI 10.17182/hepdata.46686

Dijet events in photon-proton collisions in which there is a large pseudorapidity separation Delta eta > 2.5 between the two highest E_T jets are studied with the H1 detector at HERA. The inclusive dijet cross sections are measured as functions of the longitudinal momentum fractions of the proton and photon which participate in the production of the jets, x_pjet and x_gjet respectively, Delta eta, the pseudorapidity separation between the two highest E_T jets, and E_T^gap, the total summed transverse energy between the jets. Rapidity gap events are defined as events in which E_T^gap is less than E_T^cut, for E_T^cut varied between 0.5 and 2.0 GeV. The fraction of dijet events with a rapidity gap is measured differentially in Delta eta, x_pjet and x_gjet. An excess of events with rapidity gaps at low values of E_T^cut is observed above the expectation from standard photoproduction processes. This excess can be explained by the exchange of a strongly interacting colour singlet object between the jets.

16 data tables

The inclusive dijet cross section as a function of X(C=GAMMA).

The inclusive dijet cross section as a function of XP.

The inclusive dijet cross section as a function of the rapidity gap.

More…

Inclusive dijet production at low Bjorken-x in deep inelastic scattering.

The H1 collaboration Aktas, A. ; Andreev, V. ; Anthonis, T. ; et al.
Eur.Phys.J.C 33 (2004) 477-493, 2004.
Inspire Record 630329 DOI 10.17182/hepdata.46329

Dijet production in deep inelastic ep scattering is investigated in the region of low values of the Bjorken-variable x (10^-4 &lt; x &lt; 10^-2) and low photon virtualities Q^2 (5 &lt; Q^2 &lt; 100 GeV^2). The measured dijet cross sections are compared with perturbative QCD calculations in next-to-leading order. For most dijet variables studied, these calculations can provide a reasonable description of the data over the full phase space region covered, including the region of very low x. However, large discrepancies are observed for events with small separation in azimuth between the two highest transverse momentum jets. This region of phase space is described better by predictions based on the CCFM evolution equation, which incorporates k_t factorized unintegrated parton distributions. A reasonable description is also obtained using the Color Dipole Model or models incorporating virtual photon structure.

15 data tables

Inclusive dijet cross section for a lower ET cut off of (5+0) GeV for the highest ET jet.

Inclusive dijet cross section for a lower ET cut off of (5+1) GeV for the highest ET jet.

Inclusive dijet cross section for a lower ET cut off of (5+2) GeV for the highest ET jet.

More…

Jets and energy flow in photon - proton collisions at HERA

The H1 collaboration Aid, S. ; Andreev, V. ; Andrieu, B. ; et al.
Z.Phys.C 70 (1996) 17-30, 1996.
Inspire Record 402890 DOI 10.17182/hepdata.44935

Properties of the hadronic final state in photoproduction events with large transverse energy are studied at the electron-proton collider HERA. Distributions of the transverse energy, jets and underlying event energy are compared to $\overline{p}p$ data and QCD calculations. The comparisons show that the $\gamma p$ events can be consistently described by QCD models including -- in addition to the primary hard scattering process -- interactions between the two beam remnants. The differential jet cross sections $d\sigma/dE_T~{jet}$ and $d\sigma/d\eta~{jet}$ are measured.

3 data tables

No description provided.

Additional overall systematic error of 26 pct.

Additional overall systematic error of 26 pct.


Low Q**2 jet production at HERA and virtual photon structure.

The H1 collaboration Adloff, C. ; Aid, S. ; Anderson, M. ; et al.
Phys.Lett.B 415 (1997) 418-434, 1997.
Inspire Record 448449 DOI 10.17182/hepdata.44498

The transition between photoproduction and deep-inelastic scattering is investigated in jet production at the HERA ep collider, using data collected by the H1 experiment. Measurements of the differential inclusive jet cross-sections dsigep/dEt* and dsigmep/deta*, where Et* and eta* are the transverse energy and the pseudorapidity of the jets in the virtual photon-proton centre of mass frame, are presented for 0 < Q2 < 49 GeV2 and 0.3 < y < 0.6. The interpretation of the results in terms of the structure of the virtual photon is discussed. The data are best described by QCD calculations which include a partonic structure of the virtual photon that evolves with Q2.

22 data tables

The ET differential jet cross section in the virtual-photon CM frame.

The ET differential jet cross section in the virtual-photon CM frame.

The ET differential jet cross section in the virtual-photon CM frame.

More…

Measurement of dijet cross-sections in photoproduction at HERA

The H1 collaboration Adloff, C. ; Andreev, V. ; Andrieu, B. ; et al.
Eur.Phys.J.C 25 (2002) 13-23, 2002.
Inspire Record 581409 DOI 10.17182/hepdata.46764

Dijet cross sections as functions of several jet observables are measured in photoproduction using the H1 detector at HERA. The data sample comprises e^+p data with an integrated luminosity of 34.9 pb^(-1). Jets are selected using the inclusive k_T algorithm with a minimum transverse energy of 25 GeV for the leading jet. The phase space covers longitudinal proton momentum fraction x_p and photon longitudinal momentum fraction x_gamma in the ranges 0.05<x_p<0.6 and 0.1<x_gamma<1. The predictions of next-to-leading order perturbative QCD, including recent photon and proton parton densities, are found to be compatible with the data in a wide kinematical range.

10 data tables

Differential ep cross section for dijet production as a function of the invariant mass of the two jets.

Differential ep cross section for dijet production as a function of the average transverse energy the two jets.

Differential ep cross section for dijet production as a function of the maximum transverse energy the leading jet.

More…

Measurement of inclusive jet cross-sections in deep-inelastic e p scattering at HERA.

The H1 collaboration Adloff, C. ; Andreev, V. ; Andrieu, B. ; et al.
Phys.Lett.B 542 (2002) 193-206, 2002.
Inspire Record 588263 DOI 10.17182/hepdata.46544

A measurement of inclusive jet cross-sections in deep-inelastic ep scattering at HERA is presented based on data with an integrated luminosity of 21.1 pb^-1. The measurement is performed for photon virtualities Q^2 between 5 and 100 GeV^2, differentially in Q^2, in the jet transverse energy E_T, in E_T^2/Q^2 and in the pseudorapidity eta_lab. With the renormalization scale mu_R = E_T, perturbative QCD calculations in next-to-leading order (NLO) give a good description of the data in most of the phase space. Significant discrepancies are observed only for jets in the proton beam direction with E_T below 20 GeV and Q^2 below 20 GeV^2. This corresponds to the region in which NLO corrections are largest and further improvement of the calculations is thus of particular interest.

5 data tables

Inclusive jet cross sections DSIG/DET(JET) as a function of ET(JET) in three pseudorapidity ranges.

Inclusive jet cross sections DSIG/DET(JET) as a function of ET(JET) in five Q**2 ranges for the forward pseudorapidity range 1.5 to 2.8.

Inclusive jet cross section DSIG/D(ET**2/Q**2) in the pseudorapidity range -1.0 to 0.5.

More…

Measurement of inclusive jet cross-sections in photoproduction at HERA

The H1 collaboration Abt, I. ; Ahmed, T. ; Andreev, V. ; et al.
Phys.Lett.B 314 (1993) 436-444, 1993.
Inspire Record 356741 DOI 10.17182/hepdata.28821

The inclusive jet cross section in photoproduction has been measured as a function of transverse energy and pseudorapidity using the H 1 detector at the HERA electron-proton collider. The results are compared with leading order QCD calculations.

2 data tables

No description provided.

No description provided.