المؤلفون: Iain W. Stewart, Andrew J. Larkoski, Duff Neill

المساهمون: Massachusetts Institute of Technology. Center for Theoretical Physics, Massachusetts Institute of Technology. Department of Physics, Massachusetts Institute of Technology. Laboratory for Nuclear Science, Larkoski, Andrew, Neill, Duff Austin, Stewart, Iain

المصدر: Springer-Verlag
Journal of High Energy Physics

مصطلحات موضوعية: Quantum chromodynamics, Physics, High Energy Physics - Theory, Particle physics, Gauge boson, Nuclear and High Energy Physics, Nuclear Theory, FOS: Physical sciences, Nuclear Theory (nucl-th), Theoretical physics, High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), Soft-collinear effective theory, High Energy Physics - Theory (hep-th), Effective field theory, Gauge theory, Angular momentum operator, Quantum field theory, S-matrix

الوصف: The singular limits of massless gauge theory amplitudes are described by an effective theory, called soft-collinear effective theory (SCET), which has been applied most successfully to make all-orders predictions for observables in collider physics and weak decays. At tree-level, the emission of a soft gauge boson at subleading order in its energy is given by the Low-Burnett-Kroll theorem, with the angular momentum operator acting on a lower-point amplitude. For well separated particles at tree-level, we prove the Low-Burnett-Kroll theorem using matrix elements of subleading SCET Lagrangian and operator insertions which are individually gauge invariant. These contributions are uniquely determined by gauge invariance and the reparametrization invariance (RPI) symmetry of SCET. RPI in SCET is connected to the infinite-dimensional asymptotic symmetries of the S-matrix. The Low-Burnett-Kroll theorem is generically spoiled by on-shell corrections, including collinear loops and collinear emissions. We demonstrate this explicitly both at tree-level and at one-loop. The effective theory correctly describes these configurations, and we generalize the Low-Burnett-Kroll theorem into a new one-loop subleading soft theorem for amplitudes. Our analysis is presented in a manner that illustrates the wider utility of using effective theory techniques to understand the perturbative S-matrix.
United States. Dept. of Energy. Office of Nuclear Physics (DE-SC0011090)
United States. Dept. of Energy. Office of High Energy Physics (DE-SC00012567)
Simons Foundation (Investigator Grant 327942)
MIT Department of Physics Pappalardo Program (Fellowship)

وصف الملف: application/pdf

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::5e304d02bff8081d2a9c4bf368bcd472
https://orcid.org/0000-0002-5290-8315

المؤلفون: Hongfang Liu, Krishna Rajagopal, Mindaugas Lekaveckas, Francesco D'Eramo

المساهمون: Massachusetts Institute of Technology. Center for Theoretical Physics, Massachusetts Institute of Technology. Department of Physics, D'Eramo, Francesco, Lekaveckas, Mindaugas, Liu, Hong, Rajagopal, Krishna

المصدر: Springer

مصطلحات موضوعية: Quark, Physics, Particle physics, Nuclear and High Energy Physics, Nuclear Theory, High Energy Physics::Phenomenology, FOS: Physical sciences, Parton, Heavy Ion Phenomenology, Jets, Jet (particle physics), Gluon, Nuclear physics, Nuclear Theory (nucl-th), High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), Quark–gluon plasma, Physics::Space Physics, Quasiparticle, High Energy Physics::Experiment, Jet quenching, Nucleon, Particle Physics - Phenomenology

الوصف: We calculate P (k [subscript ⊥]), the probability distribution for an energetic parton that propagates for a distance L through a medium without radiating to pick up transverse momentum k [subscript ⊥], for a medium consisting of weakly coupled quark-gluon plasma. We use full or HTL self-energies in appropriate regimes, resumming each in order to find the leading large-L behavior. The jet quenching parameter [ˆ over q] is the second moment of P (k [subscript ⊥]), and we compare our results to other determinations of this quantity in the literature, although we emphasize the importance of looking at P (k [subscript ⊥]) in its entirety. We compare our results for P (k [subscript ⊥]) in weakly coupled quark-gluon plasma to expectations from holographic calculations that assume a plasma that is strongly coupled at all length scales. We find that the shape of P (k [subscript ⊥]) at modest k [subscript ⊥] may not be very different in weakly coupled and strongly coupled plasmas, but we find that P (k [subscript ⊥]) must be parametrically larger in a weakly coupled plasma than in a strongly coupled plasma — at large enough k [subscript ⊥]. This means that by looking for rare (but not exponentially rare) large-angle deflections of the jet resulting from a parton produced initially back-to-back with a hard photon, experimentalists can find the weakly coupled short-distance quark and gluon quasiparticles within the strongly coupled liquid quark-gluon plasma produced in heavy ion collisions, much as Rutherford found nuclei within atoms or Friedman, Kendall and Taylor found quarks within nucleons.
United States. Dept. of Energy (Cooperative Research Agreement DE-FG0205ER41360)
Miller Institute for Basic Research in Science

وصف الملف: application/pdf

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::a71c3ccacbf6c6227f01fecaa5b4d777
http://hdl.handle.net/1721.1/88518

المؤلفون: Frank J. Tackmann, Claudio Marcantonini, Iain W. Stewart, Carola F. Berger, Wouter J. Waalewijn

المساهمون: Massachusetts Institute of Technology. Center for Theoretical Physics, Massachusetts Institute of Technology. Department of Physics, Stewart, Iain, Berger, Carola, Marcantonini, Claudio, Tackmann, Frank, Waalewijn, Wouter J.

المصدر: Prof. Stewart via Mat Willmott

مصطلحات موضوعية: Physics, Nuclear and High Energy Physics, Particle physics, Large Hadron Collider, Logarithm, Nuclear Theory, Astrophysics::High Energy Astrophysical Phenomena, Veto, High Energy Physics::Phenomenology, Tevatron, FOS: Physical sciences, Scale (descriptive set theory), Jet (particle physics), Gluon, High Energy Physics - Experiment, Nuclear Theory (nucl-th), High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), Higgs boson, High Energy Physics::Experiment

الوصف: A major ingredient in Higgs searches at the Tevatron and LHC is the elimination of backgrounds with jets. In current H → WW → lνlν searches, jet algorithms are used to veto central jets to obtain a 0-jet sample, which is then analyzed to discover the Higgs signal. Imposing this tight jet veto induces large double logarithms which significantly modify the Higgs production cross section. These jet-veto logarithms are presently only accounted for at fixed order or with the leading-logarithmic summation from parton-shower Monte Carlos. Here we consider Higgs production with an inclusive event-shape variable for the jet veto, namely beam thrust Tcm, which has a close correspondence with a traditional pT jet veto. Tcm allows us to systematically sum the large jet-veto logarithms to higher orders and to provide better estimates for theoretical uncertainties. We present results for the 0-jet Higgs production cross section from gluon fusion at next-to-next-to-leading-logarithmic order (NNLL), fully incorporating fixed-order results at next-to-next-to-leading order (NNLO). At this order the scale uncertainty is 15 − 20%, depending on the cut, implying that a larger scale uncertainty should be used in current Tevatron bounds on the Higgs.
United States. Dept. of Energy. Office of High Energy and Nuclear Physics (contract DE-FG02-94ER40818)
United States. Dept. of Energy (grant DE-SC003916)
Alexander von Humboldt-Stiftung

وصف الملف: application/pdf

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::2eebc20d9fa4f2e9c3a3c9e8f3a91049
http://hdl.handle.net/1721.1/71985

المؤلفون: Nicolas Borghini

مصطلحات موضوعية: Physics, Nuclear Theory (nucl-th), High Energy Physics - Phenomenology, Formalism (philosophy of mathematics), Particle physics, High Energy Physics - Phenomenology (hep-ph), Nuclear Theory, Physics and Astronomy (miscellaneous), Momentum conservation, FOS: Physical sciences, Nuclear Experiment, Engineering (miscellaneous), Mathematical physics

الوصف: Using a generating-function formalism, we compute the contribution of momentum conservation to multiparticle correlations between the emitted particles in high-energy collisions. In particular, we derive a compact expression of the genuine M-particle correlation, for arbitrary M.
Comment: 5 pages, RevTeX. v2: typos corrected, to match journal version

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::08347e67efcedc3a06b5a1101d049a89
https://pub.uni-bielefeld.de/record/2322421

المؤلفون: M. Weber, A. Brandenburg, P.M. Zerwas, Markos Maniatis

المصدر: The European physical journal / C 58, 291 (2008). doi:10.1140/epjc/s10052-008-0770-8

مصطلحات موضوعية: Particle physics, Physics and Astronomy (miscellaneous), High Energy Physics::Lattice, Nuclear Theory, FOS: Physical sciences, 01 natural sciences, law.invention, Identity (mathematics), High Energy Physics - Phenomenology (hep-ph), law, 0103 physical sciences, ddc:530, 010306 general physics, Collider, Engineering (miscellaneous), Coupling, Quantum chromodynamics, Physics, Large Hadron Collider, 010308 nuclear & particles physics, High Energy Physics::Phenomenology, Yukawa potential, Supersymmetry, Gauge (firearms), High Energy Physics - Phenomenology, High Energy Physics::Experiment

الوصف: Supersymmetry predicts the identity of Yukawa and gauge couplings in the QCD sector: quark-squark-gluino = squark-squark-gluon = quark-quark-gluon. We examine whether the quark-squark-gluino Yukawa coupling can be determined, by methods complementary to LHC, by analyzing squark-gluino final states at a TeV e+e- collider.
Comment: 14 pages, 13 figures

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::c41a0d6f538e5be0ee093f1916ea1b33
https://pub.uni-bielefeld.de/record/2375797