HEPData Search

Showing 6 of 6 results

Measurement of the cross section and longitudinal double-spin asymmetry for di-jet production in polarized $pp$ collisions at $\sqrt{s}$ = 200 GeV

The STAR collaboration Adamczyk, L. ; Adkins, J.K. ; Agakishiev, G. ; et al.

Phys.Rev.D 95 (2017) 071103, 2017.

Inspire Record 1493842 DOI 10.17182/hepdata.77208

We report the first measurement of the longitudinal double-spin asymmetry $A_{LL}$ for mid-rapidity di-jet production in polarized $pp$ collisions at a center-of-mass energy of $\sqrt{s} = 200$ GeV. The di-jet cross section was measured and is shown to be consistent with next-to-leading order (NLO) perturbative QCD predictions. $A_{LL}$ results are presented for two distinct topologies, defined by the jet pseudorapidities, and are compared to predictions from several recent NLO global analyses. The measured asymmetries, the first such correlation measurements, support those analyses that find positive gluon polarization at the level of roughly 0.2 over the region of Bjorken-$x > 0.05$.

10 data tables

Table 1

Data simulation comparison (with arbitrary normalization). Di-jet invariant mass.

Table 2

Data simulation comparison (with arbitrary normalization). Difference between jet pseudorapidities.

Table 3

Data simulation comparison (with arbitrary normalization). Difference between jet azimuthal angles.

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Forward-jet production in deep inelastic ep scattering at HERA

The ZEUS collaboration Chekanov, S. ; Derrick, M. ; Magill, S. ; et al.

Eur.Phys.J.C 52 (2007) 515-530, 2007.

Inspire Record 756364 DOI 10.17182/hepdata.45524

Forward jet cross sections have been measured in neutral current deep inelastic scattering at low Bjorken-x with the ZEUS detector at HERA using an integrated luminosity of ${81.8 \rm pb}^{-1}$. Measurements are presented for inclusive forward jets as well as for forward jets accompanied by a dijet system. The explored phase space, with jet pseudorapidity up to 4.3 is expected to be particularly sensitive to the dynamics of QCD parton evolution at low x. The measurements are compared to fixed-order QCD calculations and to leading-order parton-shower Monte Carlo models.

14 data tables

Table 1

Differential cross section DSIG/DQ**2 in bins of Q**2 .

Table 2

Differential cross section DSIG/DX in bins of X .

Table 3

Differential cross section DSIG/DET(P=4) in bins of ET(P=4) .

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Measurement of (anti)deuteron and (anti)proton production in DIS at HERA

The ZEUS collaboration Chekanov, S. ; Derrick, M. ; Magill, S. ; et al.

Nucl.Phys.B 786 (2007) 181-205, 2007.

Inspire Record 751504 DOI 10.17182/hepdata.45516

The first observation of (anti)deuterons in deep inelastic scattering at HERA has been made with the ZEUS detector at a centre-of-mass energy of 300--318 GeV using an integrated luminosity of 120 pb-1. The measurement was performed in the central rapidity region for transverse momentum per unit of mass in the range 0.3<p_T/M<0.7. The particle rates have been extracted and interpreted in terms of the coalescence model. The (anti)deuteron production yield is smaller than the (anti)proton yield by approximately three orders of magnitude, consistent with the world measurements.

7 data tables

Table 1

Measured invariant cross section for P production.

Table 2

Measured invariant cross section for DEUT production.

Table 3

Measured invariant cross section for PBAR production.

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Scaling violations and determination of alpha(s) from jet production in gamma p interactions at HERA.

The ZEUS collaboration Chekanov, S. ; Krakauer, D. ; Loizides, J.H. ; et al.

Phys.Lett.B 560 (2003) 7-23, 2003.

Inspire Record 605584 DOI 10.17182/hepdata.46502

Differential cross sections for jet photoproduction in the reaction ep --> e jet X have been measured with the ZEUS detector at HERA using 82.2 pb^-1 of integrated luminosity. Inclusive jet cross sections are presented as a function of the jet transverse energy, E_T^jet, for jets with E_T^jet > 17 GeV and pseudorapidity -1 < eta^jet < 2.5, in the gamma-p centre-of-mass-energy range 142 < W_gamma-p < 293 GeV. Scaled jet invariant cross sections are presented as a function of the dimensionless variable x_T = 2 E_T^jet/W_gamma-p for <W_gamma-p> = 180 and 255 GeV. Next-to-leading-order QCD calculations give a good description of the measured differential cross sections in both magnitude and shape. The ratio of scaled jet invariant cross sections at the two <W_gamma-p> values shows clear non-scaling behaviour. A value for the strong coupling constant of alpha_s(M_Z) = 0.1224 +- 0.0001 (stat.) + 0.0022 - 0.0019 (exp.) + 0.0054 - 0.0042 (th.) has been extracted from a QCD analysis of the measured dsigma/dE_T^jet. The variation of alpha_s with E_T^jet is in good agreement with the running of alpha_s as predicted by QCD.

3 data tables

Table 1

Measured inclusive jet cross section.

Table 2

Measured scaled jet invariant cross section in two W intervals.

Table 3

Ratio of the measured scaled jet invariant cross section in the two W intervals.

The Dijet mass spectrum and a search for quark compositeness in anti-p p collisions at S**(1/2) = 1.8-TeV

The D0 collaboration Abbott, B. ; Abolins, M. ; Abramov, V. ; et al.

Phys.Rev.Lett. 82 (1999) 2457-2462, 1999.

Inspire Record 473420 DOI 10.17182/hepdata.42143

Using the DZero detector at the 1.8 TeV pbarp Fermilab Tevatron collider, we have measured the inclusive dijet mass spectrum in the central pseudorapidity region |eta_jet| < 1.0 for dijet masses greater than 200 Gev/c^2. We have also measured the ratio of spectra sigma(|eta_jet| < 0.5)/sigma(0.5 < |eta_jet| < 1.0). The order alpha_s^3 QCD predictions are in good agreement with the data and we rule out models of quark compositeness with a contact interaction scale < 2.4 TeV at the 95% confidence level.

2 data tables

Table 1

Dijet cross section for ABS(ETARAP)<1.0.

Table 2

Ratio of cross sections for ABS(ETARAP) < 0.5 / 0.5 < ABS(ETARAP) < 1.0.