26 research outputs found
Gauge invariant definition of the jet quenching parameter
In the framework of Soft-Collinear Effective Theory, the jet quenching
parameter, , has been evaluated by adding the effect of Glauber gluon
interactions to the propagation of a highly-energetic collinear parton in a
medium. The result, which holds in covariant gauges, has been expressed in
terms of the expectation value of two Wilson lines stretching along the
direction of the four-momentum of the parton. In this paper, we show how that
expression can be generalized to an arbitrary gauge by the addition of
transverse Wilson lines. The transverse Wilson lines are explicitly computed by
resumming interactions of the parton with Glauber gluons that appear only in
non-covariant gauges. As an application of our result, we discuss the
contribution to coming from transverse momenta of order in a
medium that is a weakly-coupled quark-gluon plasma.Comment: 31 pages, 7 figures; journal versio
Three-Body Halo States in Effective Field Theory: Renormalization and Three-Body Interactions in the Helium-6 System
In this paper we study the renormalization of Halo effective field theory applied to the Helium-6 halo nucleus seen as an alpha-neutron-neutron three-body state. We include the 0(+) dineutron channel together with both the 3/2(-) and 1/2(-) neutron-alpha channels into the field theory and study all of the six lowest-order three-body interactions that are present. Furthermore, we discuss three different prescriptions to handle the unphysical poles in the P-wave two-body sector. In the simpler field theory without the 1/2(-) channel present we find that the bound-state spectrum of the field theory is renormalized by the inclusion of a single three-body interaction. However, in the field theory with both the 3/2(-) and 1/2(-) included, the system can not be renormalized by only one three-body operator
QCD and strongly coupled gauge theories : challenges and perspectives
We highlight the progress, current status, and open challenges of QCD-driven physics, in theory and in experiment. We discuss how the strong interaction is intimately connected to a broad sweep of physical problems, in settings ranging from astrophysics and cosmology to strongly coupled, complex systems in particle and condensed-matter physics, as well as to searches for physics beyond the Standard Model. We also discuss how success in describing the strong interaction impacts other fields, and, in turn, how such subjects can impact studies of the strong interaction. In the course of the work we offer a perspective on the many research streams which flow into and out of QCD, as well as a vision for future developments.Peer reviewe
Forward production of mesons in collisions at and 8TeV
The production of mesons in collisions at and
is studied with the LHCb detector using data samples
corresponding to an integrated luminosity of and
respectively. The production cross-sections and ratios of
cross-sections are measured as functions of the meson transverse momentum
and rapidity , for } and .Comment: 36 pages, 7 figures, 16 tables. All figures and tables, along with
any supplementary material and additional information, are available at
https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-045.htm
A synthesis of the ecological processes influencing variation in life history and movement patterns of American eel: towards a global assessment
A method for sensitivity analysis to assess the effects of measurement error in multiple exposure variables using external validation data
Cognitive tactics of Bengalese finch (Lonchura striata var. domestica) for song discrimination in a go/no-go operant task
The Role of Metalanguage in an Explicit Literacy Instruction on Scientific Explanation
This paper illustrates the role of metalanguage in an explicit literacy instruction to talk about the forms and functions of scientific genres, particularly the genre of explanation. In the context of science, metalanguage refers to the technical terms for talking about scientific language using words like law, hypothesis, and evidence. Despite many efforts to use literacy strategies to address the challenges of learning scientific language, the conventional genres commonly found in science remain implicit in most science classroom teaching. In order to explicitly discuss the nature of scientific genres and how they are linked to scientific practices, scientific metalanguage provides a potential literacy tool. To illustrate this argument, we draw on a case study where four teachers and their grade 9 students learned how to use a specific type of metalanguage to describe scientific explanation. Analysis of their classroom discourse showed that the use of the metalanguage facilitated explicit communication about the logical sequence, epistemic structure, and validity of scientific explanation. Based on the findings, we discuss the usefulness of metalanguage for teachers and students to describe and analyze scientific genres as well as how these genres are used to construct and communicate scientific knowledge