Measurement of the Single Jet Invariant Cross-section at {Fermilab}

The E609 collaboration Cormell, L.R. ; Arenton, M.W. ; Chen, H.F. ; et al.
Phys.Lett.B 150 (1985) 322-326, 1985.
Inspire Record 206286 DOI 10.17182/hepdata.30447

In an experiment performed at Fermilab we have studied the production of high p t hadron jets from 400 GeV/ c pp interactions. A large solid-angle, towered calorimeter was used to trigger and reconstruct the jet events. We report results for inclusive single-jet production and compare those results with QCD predictions and results obtained at the ISR and the SPS Collider.

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Improved measurement of the anti-d/anti-u asymmetry in the nucleon sea.

The NuSea collaboration Towell, R.S. ; McGaughey, P.L. ; Awes, T.C. ; et al.
Phys.Rev.D 64 (2001) 052002, 2001.
Inspire Record 554316 DOI 10.17182/hepdata.22184

Measurements of the ratio of Drell-Yan yields from an 800 \rm{GeV/c} proton beam incident on liquid hydrogen and deuterium targets are reported. Approximately 360,000 Drell-Yan muon pairs remained after all cuts on the data. From these data, the ratio of anti-down ($\bar{d}$) to anti-up ($\bar{u}$) quark distributions in the proton sea is determined over a wide range in Bjorken-$x$. These results confirm previous measurements by E866 and extend them to lower $x$. From these data, $(\bar{d}-\bar{u})$ and $\int(\bar{d}-\bar{u})dx$ are evaluated for $0.015<x<0.35$. These results are compared with parameterizations of various parton distribution functions, models and experimental results from NA51, NMC, and HERMES.

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NEUTRAL PARTICLE PRODUCTION IN PI P INTERACTIONS AT 147-GeV/c AND COMPARISON TO CHARGED PARTICLE PRODUCTION

Brick, D. ; Fong, D. ; Heller, M. ; et al.
Phys.Rev.D 20 (1979) 2123-2134, 1979.
Inspire Record 147455 DOI 10.17182/hepdata.4386

The production of KS, Λ, Λ¯, and γ in π−p collisions at 147 GeV/c is analyzed. Cross sections, rapidity, Feynman-x, and pT2 distributions are presented and compared to charged-particle production. The energy dependence of multiplicities in π−p and pp collisions is shown. A new scaling form for the correlation of neutral- and charged-particle multiplicities is presented for compilations of πp and pp data.

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Average Charged Particle Multiplicities in $\pi^- P$ Inclusive Reactions at 147-{GeV}/$c$

Brick, D. ; Fong, D. ; Heller, M. ; et al.
Phys.Rev.D 19 (1979) 743, 1979.
Inspire Record 140350 DOI 10.17182/hepdata.4430

The experimentally determined average charged-particle multiplicities, 〈nX〉, of the systems, X, produced in the following reactions for 147 GeV/c incident pion momentum are presented as functions of the square of the invariant mass of X, MX2, and of |t|:π−p→πfast−X, π−p→pX, π−p→Δ++X, π−p→(π−π+)ρ0X, and π−p→Λ0X. Details of the analysis are discussed. These data can be fit by the expression 〈nX〉=A+B ln MX2+C|t| and the coefficients obtained for B are equal within their uncertainties. C is significantly different from zero only for π−p→πfast−X. These results and 〈nX〉 data from other inclusive and total-inelastic-reaction studies are discussed in terms of a simple model which assumes contributions to 〈nX〉 from the target-fragmentation, the central, and the beam-fragmentation regions in the case of total-inelastic reactions. For inclusive reactions, either the beam or target fragmentation is replaced by an exchange-particle-fragmentation contribution. The s, t, and MX2 dependence of the parameters of the model are deduced from triple-Regge considerations. The data are found to be consistent with the model and values are presented for the parameters.

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Measurement of the light antiquark flavor asymmetry in the nucleon sea.

The NuSea collaboration Hawker, E.A. ; Awes, T.C. ; Beddo, M.E. ; et al.
Phys.Rev.Lett. 80 (1998) 3715-3718, 1998.
Inspire Record 468098 DOI 10.17182/hepdata.42153

A precise measurement of the ratio of Drell-Yan yields from an 800 GeV/c proton beam incident on hydrogen and deuterium targets is reported. Over 140,000 Drell-Yan muon pairs with dimuon mass M_{mu+ mu-} >= 4.5 GeV/c^2 were recorded. From these data, the ratio of anti-down (dbar) to anti-up (ubar) quark distributions in the proton sea is determined over a wide range in Bjorken-x. A strong x dependence is observed in the ratio dbar/ubar, showing substantial enhancement of dbar with respect to ubar for x<0.2. This result is in fair agreement with recent parton distribution parameterizations of the sea. For x>0.2, the observed dbar/ubar ratio is much nearer unity than given by the parameterizations.

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Comparison of Spin Asymmetries and Cross Sections in $\pi^0$ Production by 200 GeV Polarized Antiprotons and Protons

The E581 & E704 collaborations Adams, D.L. ; Akchurin, N. ; Belikov, N.I. ; et al.
Phys.Lett.B 261 (1991) 201-206, 1991.
Inspire Record 314232 DOI 10.17182/hepdata.29396

None

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Measurement of the Dijet Cross-Section in 400-GeV p p Collisions

The E-609 collaboration Arenton, M.W. ; Ditzler, W.R. ; Fields, T.H. ; et al.
Phys.Rev.Lett. 53 (1984) 1988, 1984.
Inspire Record 15116 DOI 10.17182/hepdata.23566

The invariant cross section for production of jet pairs in 400-GeV/c pp interactions has been measured as a function of pT in the pT range 4 to 9 GeV/c. The results are in good agreement with predictions of perturbative QCD models.

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First Results for the Two Spin Parameter $A_{LL}$ in $\pi^0$ Production by 200-GeV Polarized Protons and Antiprotons

The E581 & E704 collaborations Adams, D.L. ; Akchurin, N. ; Belikov, N.I. ; et al.
Phys.Lett.B 261 (1991) 197-200, 1991.
Inspire Record 314233 DOI 10.17182/hepdata.29385

The two-spin parameter A LL in inclusive π 0 productionby longitudinally-polarized protons and antiprotons on a longitudinally-polarized proton target has been measured at the 200 GeV Fermilab spin physics facility, for π 0 's at x F =0 with 1⩽ p t ⩽3 GeV/ c . The results exclude, at the 95% confidence level, values of A LL (pp) > 0.1 and < − 0.1 for π 0 's produced by protons, and values of A LL ( p p) > 0.1 and < −0.2 for incident antiprotons. The relevance of A LL (pp) for the gluon spin density is discussed. The data are in good agreement with “conventional”, small or zero, gluon polarization.

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Spin transfer in inclusive Lambda0 production by transversely polarized protons at 200-GeV/c.

The E704 collaboration Bravar, A. ; Adams, D.L. ; Akchurin, N. ; et al.
Phys.Rev.Lett. 78 (1997) 4003-4006, 1997.
Inspire Record 449327 DOI 10.17182/hepdata.19560

Surprisingly large polarizations in hyperon production by unpolarized protons have been known for a long time. The spin dynamics of the production process can be further investigated with polarized beams. Recently, a negative asymmetry AN was found in inclusive Λ0 production with a 200GeV/c transversely polarized proton beam. The depolarization DNN in p↑+p→Λ0+X has been measured with the same beam over a wide xF range and at moderate pT. DNN reaches positive values of about 30% at high xF and pT∼1.0GeV/c. This result shows a sizable spin transfer from the incident polarized proton to the outgoing Λ0.

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Analyzing power measurement in inclusive Lambda0 production with a 200-GeV/c polarized proton beam

The E704 collaboration Bravar, A. ; Adams, D.L. ; Akchurin, N. ; et al.
Phys.Rev.Lett. 75 (1995) 3073-3077, 1995.
Inspire Record 406598 DOI 10.17182/hepdata.19610

The considerable polarization of hyperons produced at high xF has been known for a long time and has been interpreted with various theoretical models in terms of the constituents' spin. Recently, the analyzing power in inclusive Λ0 hyperon production has also been measured using the 200GeV/c Fermilab polarized proton beam. The covered kinematic range is 0.2≤xF≤1.0 and 0.1≤pT≤1.5GeV/c. The data indicate a negative asymmetry at large xF and moderate pT. These results can further test the current ideas on the underlying mechanisms for hyperon polarization.

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