Parton

About: Parton is a research topic. Over the lifetime, 13484 publications have been published within this topic receiving 368877 citations.

Heavy Quarks Above the Top at the Tevatron

Abstract: Recent developments in models with warped extra dimensions have opened new possibilities for vectorlike quark studies at hadron colliders. These new vectorlike quarks can mix sizably with light standard model quarks without violating low energy constraints. We perform a model-independent analysis to determine the Tevatron reach in the search for new quarks. We find that the Tevatron has great potential to observe such quarks via their electroweak single production due to their mixing with valence quarks. With 4(8) fb -1 integrated luminosity, one may reach a 5σ statistical significance for a heavy quark of mass 580(630) GeV if the heavy quark-Standard Model quark mixing parameter is order one.

Revisiting slepton pair production at the Large Hadron Collider

Abstract: Motivated by the shift in experimental attention towards electroweak super-symmetric particle production at the CERN LHC, we update in this paper our precision predictions at next-to-leading order of perturbative QCD matched to resummation at the next-to-leading logarithmic accuracy for direct slepton pair production in proton-proton collisions. Simplified models, now commonly adopted by the experimental collaborations for selectrons and smuons as well as mixing staus, are used as benchmarks for total cross sections at achieved and future center-of-mass energies. They are presented together with the corresponding scale and parton density uncertainties in graphical and tabular form for future reference. Using modern Monte Carlo techniques, we also reanalyze recent ATLAS and CMS slepton searches in light of our precision cross sections and for various assumptions on the decomposition of the sleptons and their neutralino decay products.

Soft gluons at large angles in hadron collisions

Abstract: A general discussion is presented of the single logarithmic soft factor that appears in two scale QCD observables in processes involving four partons. We treat it as the ``fifth form factor'', accompanying the four collinear singular Sudakov form factors attached to colliding and outgoing hard partons. The fifth form factor is expressed in terms of the Casimir operators (squared colour charges) of irreducible representations in the crossing t- and u-channels. As an application we revisit the problem of large angle radiation in gg→gg and give a relatively simple solution and interpretation of the results. We found an unexpected symmetry of the soft anomalous dimension under exchange of internal and external variables of the problem whose existence calls for explanation.