Constraints on color-octet fermions from a global parton distribution analysis

Abstract

We report a parton distribution function (PDF) analysis of a complete set of hadron scattering data, in which a color-octet fermion (such as a gluino of supersymmetry) is incorporated as an extra parton constituent along with the usual standard model constituents. The data set includes the most up-to-date results from deep-inelastic scattering and from jet production in hadron collisions. Another feature is the inclusion in the fit of data from determinations of the strong coupling alpha_s(Q) at large and small values of the hard scale Q. Our motivation is to determine the extent to which the global PDF analysis may provide constraints on the new fermion, as a function of its mass and alpha_s(M_Z), independent of assumptions such as the mechanism of gluino decays. Based on this analysis, we find that gluino masses as low as 30 to 50 GeV may be compatible with the current hadronic data. Gluino masses below 15 GeV (25 GeV) are excluded if alpha_s(M_Z) varies freely (is equal to 0.118). At the outset, stronger constraints had been anticipated from jet production cross sections, but experimental systematic uncertainties, particularly in normalization, reduce the discriminating power of these data.

36 pages, 14 figures. Accepted for a publication on Phys. Rev. D (2010)

References in corpus (43)

• A Large Mass Hierarchy from a Small Extra Dimension
• New Generation of Parton Distributions with Uncertainties from Global QCD Analysis
• Big-Bang nucleosynthesis (Particle Data Group mini-review)
• The Cosmological Parameters 2006
• New parton distributions for collider physics
• Implications of CTEQ global analysis for collider observables
• MadGraph/MadEvent v4: The New Web Generation
• Bounds on Universal Extra Dimensions
• Electroweak symmetry breaking from dimensional deconstruction
• Supersymmetric Unification Without Low Energy Supersymmetry And Signatures for Fine-Tuning at the LHC
• Combined Measurement and QCD Analysis of the Inclusive ep Scattering Cross Sections at HERA
• Hadronic Z- and tau-Decays in Order alpha_s^4
• Techniques for improved heavy particle searches with jet substructure
• Hard-scattering factorization with heavy quarks: A general treatment
• Measurement of the inclusive jet cross section in $p\bar{p}$ collisions at $\sqrt{s}=1.96\mathrm{TeV}$
• A precise determination of alpha_s from LEP thrust data using effective field theory
• Strategies to Identify Boosted Tops
• Supersymmetry Without Prejudice
• Substructure of high-p_T Jets at the LHC
• Treatment of Heavy Quarks in Deeply Inelastic Scattering
• Measurement of the Inclusive Jet Cross Section at the Fermilab Tevatron p-pbar Collider Using a Cone-Based Jet Algorithm
• Uncertainty induced by QCD coupling in the CTEQ global analysis of parton distributions
• Searching for Directly Decaying Gluinos at the Tevatron
• Measurement of the Inclusive Jet Cross Section using the k_T algorithm in pp-bar Collisions at sqrt(s) = 1.96 TeV with the CDF II Detector
• Top Jets at the LHC
• Search for squarks and gluinos in events with jets and missing transverse energy using 2.1 fb-1 of ppbar collision data at sqrt(s)=1.96 TeV
• Determination of the strong coupling constant using matched NNLO+NLLA predictions for hadronic event shapes in e+e- annihilations
• Low-Energy Supersymmetry and the Tevatron Bottom-Quark Cross Section
• Measurement of the Inclusive Jet Cross Section in $\bar{p}p$ collisions at $\sqrt{s}=1.8$ TeV
• Determination of the strong coupling constant from the inclusive jet cross section in ppbar collisions at sqrt(s)=1.96 TeV
• Inclusive Search for Squark and Gluino Production in ppbar Collisions at sqrt{s} = 1.96 TeV
• High-p_T Jets in pbarp Collisions at sqrt{s} = 630 and 1800 GeV
• Non-Perturbative Contribution to the Thrust Distribution in $e^{+}{e}^{-}$ Annihilation
• Search for Large Extra Dimensions in the Production of Jets and Missing Transverse Energy in $p\bar{p}$ Collisions at $\sqrt{s}$ = 1.96 TeV
• Search for stopped gluinos from p-pbar collisions at sqrt(s)=1.96 TeV
• Search for squarks and gluinos in events with jets and missing transverse energy in ppbar collisions at sqrt(s)=1.96 TeV
• Constraining Light Colored Particles with Event Shapes
• Collider Inclusive Jet Data and the Gluon Distribution
• Search for stable hadronizing squarks and gluinos in e+e- collisions up to sqrt(s) = 209 GeV
• Search for Gluino-Mediated Sbottom Production in p-pbar Collisions at sqrt(s)=1.96 TeV
• Light Gluino Constituents of Hadrons and a Global Analysis of Hadron Scattering Data
• A Search for Scalar Bottom Quarks from Gluino Decays in $\bar{p}p$ Collisions at $\sqrt{s}=1.96$ TeV
• Search for squark production in events with jets, hadronically decaying tau leptons and missing transverse energy at sqrt(s)=1.96 TeV

Cited by in corpus (7)

• The Structure of the Proton in the LHC Precision Era
• Snowmass 2021 whitepaper: Proton structure at the precision frontier
• Constraining new coloured matter from the ratio of 3- to 2-jets cross sections at the LHC
• Flavor unification, dark matter, proton decay and other observable predictions with low-scale $S_4$ symmetry
• A Hybrid Scheme for Heavy Flavors: Merging the FFNS and VFNS
• The dark side of the proton
• Constraints on parton distributions and the strong coupling from LHC jet data