84 research outputs found
Forward Physics Facility Theory Workshop
No full textThe currently operating FASER experiment and the planned Forward Physics Facility (FPF) will detect a large number of neutrinos produced in proton-proton collisions at the LHC. In addition to neutrinos from pion and kaon decays, a significant contribution is expected from the decay of charmed hadrons, particularly for electron and tau neutrino flavors. In this talk, we shall discuss two QCD formulations for the production of charm quarks in collisions: the next-to-leading order collinear factorization and the -factorization approach. We use state of the art fragmentation schemes to obtain hadron cross-sections and validate them against current LHCb data. These calculations are then used to predict the forward neutrino flux from charm hadron decays. We further scrutinize the impact of varying QCD parameters, such as scales, the selection of parton distribution functions, and the modeling of fragmentation, on these predictions. Among these factors, the modeling of fragmentation has a particularly significant impact on the neutrino flux at FASER
Forward charm-production models and prompt neutrinos at IceCube
No full textpeer reviewedWe investigate the prompt neutrino background at IceCube, as determined from forward charm. We consider the role of intrinsic charm and of a recombination model and show that the contribution of these mechanisms is at most a factor two
Prompt atmospheric neutrino fluxes: perturbative QCD models and nuclear effects
No full textWe evaluate the prompt atmospheric neutrino flux at high energies using three different frameworks for calculating the heavy quark production cross section in QCD: NLO perturbative QCD, k_T factorization including low-x resummation, and the dipole model including parton saturation
Low thrust orbit transfer trajectory optimization
No full textPresented to the 11th Annual Symposium on Graduate Research and Scholarly Projects (GRASP) held at the Heskett Center, Wichita State University, April 24, 2015.Research completed at Department of Aerospace Engineering, College of EngineeringIn recent years, all electric satellites have had a growing presence in the space industry. The 702-
SP family developed by Boeing is to be used for telecommunication satellites. This spawns the
need for analyzing mission scenarios in order to achieve the most efficient way of deploying
such satellites.
The purpose of this poster is to analyze the different approaches to Low Thrust Spacecraft
Trajectory optimization. One of the methods, developed by the author uses a feedback control
law which allows the user to minimize an arbitrary objective set by mission designers. It also
allows for a combination of objectives like minimum fuel and minimum time transfers.
Minimizing radiation damage is another objective that is of importance in these kind of scenarios
due to the long transfer times. The second method is a direct optimization routine. While this
method has been around longer, convergence to a solution is not guaranteed and depends on
initial guesses provided by the user. The third method is a combination of the first two methods
and allows for multi-objective optimization. Extensive research of existing literature has shown
that such a trajectory optimization method does not exist. The advantage of this method is that it
will be able to overcome the shortcomings of the individual components and provide a
comprehensive framework for mission designers to work with. The author will go over the
merits and drawbacks of the different methods as well as compare the performance of all the
methods for multiple scenarios. Some of these metrics will include rate of change of inclination,
radius and fuel mass.
In addition to this, the author will also introduce new performance objectives that could be of
interest to mission designers and will discuss the method of implementing them into all of the
mentioned methods.Graduate School, Academic Affairs, University Librarie
Boosted Dark Matter and its implications for the features in IceCube HESE data
No full textpeer reviewedWe study the implications of the premise that any new, relativistic, highly energetic neutral particle that interacts with quarks and gluons would create cascade-like events in the IceCube (IC) detector which would be observationally indistinguishable from neutral current deep-inelastic (DIS) scattering events due to neutrinos. Consequently, one reason for deviations, breaks or excesses in the expected astrophysical power-law neutrino spectrum could be the flux of such a particle. Motivated by features in the recent 1347-day IceCube high energy starting event (HESE) data, we focus on particular boosted dark matter () related realizations of this premise, where is assumed to be much lighter than, and the result of, the slow decay of a massive scalar () which constitutes a major fraction of the Universe's dark matter (DM). We show that this hypothesis, coupled with a standard power-law astrophysical neutrino flux is capable of providing very good fits to the present data, along with a possible explanation of other features in the HESE sample: i.e., a) the paucity of events beyond PeV b) a spectral feature resembling a dip in the 400 TeV--1 PeV region and c) an excess in the TeV region. We consider two different boosted DM scenarios, and determine the allowed mass ranges and couplings for four different types of mediators (scalar, pseudoscalar, vector and axial-vector) which could connect the standard and dark sectors, imposing constraints from gamma-ray observations and collider searches. We find that the gamma-ray observations provide the most restrictive constraints, disfavouring the allowed parameter space from IC fits, while still being consistent with the allowed region. We also test our proposal and its implications against the sample of six year through-going muon track data recently released by IceCube
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