7,325 research outputs found
Further investigation of dilepton-based center-of-mass energy measurements at ee colliders
Methods for measuring the absolute center-of-mass energy using dileptons from
ee collision events are further developed with an emphasis on
accelerator, detector, and physics limitations. We discuss two main estimators,
the lepton momentum-based center-of-mass energy estimator, ,
discussed previously, and new estimators for the electron and positron
colliding beam energies, denoted and . In
this work we focus on the underlying limitations from beam energy spread,
detector resolution, and the modeling of higher-order QED radiative corrections
associated with photon emissions originating from initial-state-radiation
(ISR), final-state-radiation (FSR), and their interference. We study the
consequent implications for the potential of these methods at center-of-mass
energies ranging from 90 GeV to 1 TeV relevant to a number of potential
accelerator realizations in the context of measurements of masses of the Z, W,
H, top quark, and new particles. The statistical importance of the Bhabha
channel for Higgs factories is noted. Additional extensive work on improving
the modeling of the luminosity spectrum including the use of copulas is also
reported.Comment: 22 pages, 10 figures, LCWS 2023 Proceeding
Center-of-mass energy determination using to events at future colliders
Methods for measuring the absolute center-of-mass energy, , and its
distribution, are investigated for future Higgs-factory colliders
using in situ collisions. We emphasize the potential of an estimator
based on the measurement of muon momenta that we denote . It can be
determined with high precision in to () events
while being sensitive to effects from beam energy spread, beamstrahlung,
initial-state radiation (ISR), final-state radiation (FSR), crossing angle, and
detector resolution. The measurement precision is enabled by a high-precision
low-mass tracker; the reported performance estimates are based on full
simulation of the tracker response of the ILD detector concept for the ILC
operating at GeV. The underlying statistical precision is 1.9
ppm for a 2.0 ab dataset at ILC. The ultimate utility will depend
largely on how well one can calibrate and maintain the tracker momentum scale.Comment: 30 pages; Submitted to the Proceedings of the US Community Study on
the Future of Particle Physics (Snowmass 2021). v3 correct scaling formula in
footnote 1 and add corresponding referenc
Radio Astronomy
Contains reports on four research projects.National Aeronautics and Space Administration (Grant NsG-240-62)National Aeronautics and Space Administration (Grant NsG-419)Lincoln Laboratory (Purchase Order DDL BB-107)U. S. Air Force (Contract AF 19(628)-500)Office of Naval Research (Contract Nonr 3963(02
Emergency supply of prescription-only medicines to patients by community pharmacists: a mixed methods evaluation incorporating patient, pharmacist and GP perspectives
Objective To evaluate and inform emergency supply of prescription-only medicines by community pharmacists (CPs), including how the service could form an integral component of established healthcare provision to maximise adherence.
Design Mixed methods. 4 phases: prospective audit of emergency supply requests for prescribed medicines (October–November 2012 and April 2013); interviews with CPs (February–April 2013); follow-up interviews with patients (April–May 2013); interactive feedback sessions with general practice teams (October–November 2013).
Setting 22 community pharmacies and 6 general practices in Northwest England.
Participants 27 CPs with experience of dealing with requests for emergency supplies; 25 patients who received an emergency supply of a prescribed medicine; 58 staff at 6 general practices.
Results Clinical audit in 22 pharmacies over two 4-week periods reported that 526 medicines were requested by 450 patients. Requests peaked over a bank holiday and around weekends. A significant number of supplies were made during practice opening hours. Most requests were for older patients and for medicines used in long-term conditions. Difficulty in renewing repeat medication (forgetting to order, or prescription delays) was the major reason for requests. The majority of medicines were ‘loaned’ in advance of a National Health Service (NHS) prescription. Interviews with CPs and patients indicated that continuous supply had a positive impact on medicines adherence, removing the need to access urgent care. General practice staff were surprised and concerned by the extent of emergency supply episodes.
Conclusions CPs regularly provide emergency supplies to patients who run out of their repeat medication, including during practice opening hours. This may aid adherence. There is currently no feedback loop, however, to general practice. Patient care and interprofessional communication may be better served by the introduction of a formally structured and funded NHS emergency supply service from community pharmacies, with ongoing optimisation of repeat prescribing
Populating the galaxy velocity dispersion - supermassive black hole mass diagram: A catalogue of (M_bh, sigma) values
An updated catalogue of 76 galaxies with direct supermassive black hole mass
measurements (M_bh) plus, when available, their host bulge's central velocity
dispersion (sigma_0) is provided. Fifty of these mass measurements are
considered reliable, while the others remain somewhat uncertain at this time.
An additional eight stellar systems, including one stellar cluster and three
globular clusters, are listed as hosting potential intermediate mass black
holes < 10^6 M_solar.
With this larger data set, the demographics within the M_bh-sigma_0 diagram
are briefly explored. Many barred galaxies are shown to be offset from the
M_bh-sigma_0 relation defined by the non-barred galaxies, in the sense that
their velocity dispersions are too high. Furthermore, including 88 AGN with
black hole mass estimates from reverberation mapping studies, we speculate that
barred AGN may follow this same general trend. We also show that some AGN with
sigma_0 < 100 km/s tend to reside up to 0.6 dex above the "barless"
M_bh-sigma_0 relation. Finally, it is shown that ``core galaxies'' appear not
to define an additional subdivision of the M_bh-sigma_0 diagram, although
improved methods for measuring sigma_0-values will be valuable.Comment: To appear in PASA, accepted on the 4th of July, 200
Seasonal total methane depletion in limestone caves
Methane concentration in caves is commonly much lower than the external atmosphere, yet the cave CH4 depletion causal mechanism is contested and dynamic links to external diurnal and seasonal temperature cycles unknown. Here, we report a continuous 3-year record of cave methane and other trace gases in Jenolan Caves, Australia which shows a seasonal cycle of extreme CH4 depletion, from ambient ∼1,775 ppb to near zero during summer and to ∼800 ppb in winter. Methanotrophic bacteria, some newly-discovered, rapidly consume methane on cave surfaces and in external karst soils with lifetimes in the cave of a few hours. Extreme bacterial selection due to the absence of alternate carbon sources for growth in the cave environment has resulted in an extremely high proportion 2-12% of methanotrophs in the total bacteria present. Unexpected seasonal bias in our cave CH4 depletion record is explained by a three-step process involving methanotrophy in aerobic karst soil above the cave, summer transport of soil-gas into the cave through epikarst, followed by further cave CH4 depletion. Disentangling cause and effect of cave gas variations by tracing sources and sinks has identified seasonal speleothem growth bias, with implied palaeo-climate record bias
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