9,135 research outputs found
Collinear factorization violation and effective field theory
The factorization of amplitudes into hard, soft and collinear parts is known
to be violated in situations where incoming particles are collinear to outgoing
ones. This result was first derived by studying limits where non-collinear
particles become collinear. We show that through an effective field theory
framework with Glauber operators, these factorization-violating effects can be
reproduced from an amplitude that is factorized before the splitting occurs. We
confirm results at one-loop, through single Glauber exchange, and at two-loops,
through double Glauber exchange. To approach the calculation, we begin by
reviewing the importance of Glauber scaling for factorization. We show that for
any situation where initial state and final state particles are not collinear,
the Glauber contribution is entirely contained in the soft contribution. The
contributions coming from Glauber operators are necessarily non-analytic
functions of external momentum, with the non-analyticity arising from the
rapidity regulator. The non-analyticity is critical so that Glauber operators
can both preserve factorization when it holds and produce
factorization-violating effects when they are present.Comment: 55 Pages, 5 figure
Factorization Violation and Scale Invariance
Factorization violating effects in hadron scattering are due mainly to
spectator-spectator interactions. While it is known that these interactions
cancel in inclusive cross sections, like for the Drell-Yan process, not much is
known about for what classes of observables factorization is violated. We show
that for pure Glauber ladder graphs, all amplitude-level factorization
violating effects completely cancel at cross section level for any single-scale
observable (such as hadronic transverse energy or beam thrust). This result
disproves previous claims that these pure Glauber graphs are
factorization-violating. Our proof exploits scale invariance of two-to-two
scattering amplitudes in an essential way. The leading factorization-violating
effects therefore come from graphs with at least one soft gluon, involving the
Lipatov vertex off of the Glauber ladders. This implies that real soft
radiation must be involved in factorization-violation, shedding light on the
connection between factorization-violation and the underlying event.Comment: 36 pages, 15 figure
Autonomous Ground Vehicle
WildCat is an autonomous ground vehicle (AGV). AGVs were first developed for military purposes: Intelligent Transportation Systems (ITS), Manufacturing, Search and Rescue operations, Mining, etc. WildCat will be entered in the Intelligent Ground Vehicle competition (IGVC) held in June 2016 at Oakland University in Rochester, Michigan. Teams from major universities not only in the U.S., but also India, France, the UK, China, and around the world will be competing.
The IGVC offers a design experience that is at the very cutting edge of engineering education. It is multidisciplinary, theory-based, hands-on, team implemented, and outcome assessed competition. It encompasses the very latest technologies impacting industrial development and taps subjects of high interest to students. The objective of the competition is to challenge students to think creatively as a team about the evolving technologies of vehicle electronic controls, sensors, computer science, robotics, and system integration throughout the design, fabrication, and field testing of autonomous intelligent mobile robots.
The vehicle will compete to: 1) autonomously navigate an outdoor obstacle course as quickly as possible, keeping within the speed limit and reaching all GPS waypoints, 2) complete a course with remote (user) control, and 3) have ingenuity and uniqueness in design
Improving Pneumococcal Vaccination Rates in Jefferson Hospital Ambulatory Practice Patients
AIM:
To improve the pneumococcal vaccination initiation rates in patients 65 years and older in Jefferson Hospital Ambulatory Practice (JHAP) to the institutional quality measure goal of 80% over a 4 month period from January to May of 2017.https://jdc.jefferson.edu/patientsafetyposters/1031/thumbnail.jp
Characterizing Location-based Mobile Tracking in Mobile Ad Networks
Mobile apps nowadays are often packaged with third-party ad libraries to
monetize user data
Scattering, Damping, and Acoustic Oscillations: Simulating the Structure of Dark Matter Halos with Relativistic Force Carriers
We demonstrate that self-interacting dark matter models with interactions
mediated by light particles can have significant deviations in the matter
power-spectrum and detailed structure of galactic halos when compared to a
standard cold dark matter scenario. While these deviations can take the form of
suppression of small scale structure that are in some ways similar to that of
warm dark matter, the self-interacting models have a much wider range of
possible phenomenology. A long-range force in the dark matter can introduce
multiple scales to the initial power spectrum, in the form of dark acoustic
oscillations and an exponential cut-off in the power spectrum. Using
simulations we show that the impact of these scales can remain observationally
relevant up to the present day. Furthermore, the self-interaction can continue
to modify the small-scale structure of the dark matter halos, reducing their
central densities and creating a dark matter core. The resulting phenomenology
is unique to this type of models.Comment: 23 pages, 11 figure
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