Measuring the Lifetime of Trapped Sleptons Using the General Purpose LHC Detectors

In supergravity where the gravitino is the lightest supersymmetric particle (LSP), the next-to-lightest supersymmetric particle (NLSP) decays to the gravitino with a naturally long lifetime (10^4 - 10^8). However, cosmological constraints favour charged sleptons with lifetimes below a year as the natural NLSP candidate. For this scenario we report a method to accurately determine the slepton lifetime and SUSY cross-section from observation of the decays of sleptons trapped in the material comprising the main detector (ATLAS, CMS). A measurement of the lifetime to 5% is possible after 3 years at nominal luminosity and running conditions. This method is sensitive to the cosmologically preferred stau lifetime of ~37 days and does not require the use of ancillary trapping volumes

Knowledge and attitudes to prescription charges in New Zealand and England

Prescription charge regimes vary between countries but there is little research on how much people know about these or support values underlying them. To explore, in New Zealand (NZ) and England, the public's knowledge of, and attitudes to, charges and whether knowledge and attitudes varied by demographic characteristics or by values about entitlement to public goods. A questionnaire was developed and administered to people over 18 recruited in public places in NZ and England. 451 people in NZ and 300 people in England participated. Less than half in each country knew the current prescription charge. In each country 62% of people were unaware of arrangements to protect people from excessive annual charges. Support for free or lower cost medicines for children, people over 65, people on low incomes, people on benefits, and people with chronic health problems was higher in England than in NZ. Support varied by participants' demographic characteristics and, in the case of people on low incomes and people on benefits, by values about universal entitlements. Gaps in knowledge, particularly about mechanisms to protect people from high costs, are concerning and may lead to people paying excessive charges. There was consensus about the elderly, children and the chronically ill being "deserving" of lower prescription charges, but people who did not believe in universal access to public goods appeared to see people on low incomes or benefits as less "deserving". In general, public views resembled those underlying the prescription charge regime in their country. [Abstract copyright: Copyright © 2017 Elsevier Inc. All rights reserved.

An exploration of stroke survivors’ perspectives on cycling and the use of electric bikes

Background New and innovative approaches are needed to overcome the barriers to engaging people in physical and leisure activity after stroke. Outdoor cycling, including the use of adapted or electric bicycles, may be one approach. However, perceptions of stroke survivors on this topic have not yet been explored. Purpose To explore a sample of stroke survivors’ perspectives, who expressed an interest in cycling, about cycling and the use of electric bicycles. Methods A convenience sample of stroke survivors were identified through focus groups at a ‘Cycling after Stroke’ event, local stroke support groups, and structured interviews at a national conference for stroke survivors. Quantitative data were analysed descriptively and qualitative data analysed thematically. Results Data were collected from 21 stroke survivors, seven of whom were current cyclists. All participants were independently mobile with, or without, the use of a walking aid. Themes oriented around the value of cycling (e.g. getting out of the house, doing something for yourself, and feeling part of a community); concerns and challenges (safety and negotiating adaptations); and how they could be overcome (starting slowly and identifying sources of assistance). Conclusion Outdoor cycling may be a worthwhile approach to increasing physical and leisure activity after stroke. However, barriers still exist and need to be addressed to provide inclusive opportunities for adapted and electric cycling for stroke survivors. Due to the small sample size and bias population, further research is needed to explore stroke survivors’ perspectives on cycling to provide solutions to overcome the barriers identified. 18

Detector Description and Performance for the First Coincidence Observations between LIGO and GEO

For 17 days in August and September 2002, the LIGO and GEO interferometer gravitational wave detectors were operated in coincidence to produce their first data for scientific analysis. Although the detectors were still far from their design sensitivity levels, the data can be used to place better upper limits on the flux of gravitational waves incident on the earth than previous direct measurements. This paper describes the instruments and the data in some detail, as a companion to analysis papers based on the first data.Comment: 41 pages, 9 figures 17 Sept 03: author list amended, minor editorial change

Upper limits on the strength of periodic gravitational waves from PSR J1939+2134

The first science run of the LIGO and GEO gravitational wave detectors presented the opportunity to test methods of searching for gravitational waves from known pulsars. Here we present new direct upper limits on the strength of waves from the pulsar PSR J1939+2134 using two independent analysis methods, one in the frequency domain using frequentist statistics and one in the time domain using Bayesian inference. Both methods show that the strain amplitude at Earth from this pulsar is less than a few times $10^{-22}$.Comment: 7 pages, 1 figure, to appear in the Proceedings of the 5th Edoardo Amaldi Conference on Gravitational Waves, Tirrenia, Pisa, Italy, 6-11 July 200

Search for Gravitational Waves from Primordial Black Hole Binary Coalescences in the Galactic Halo

We use data from the second science run of the LIGO gravitational-wave detectors to search for the gravitational waves from primordial black hole (PBH) binary coalescence with component masses in the range 0.2--$1.0 M_\odot$. The analysis requires a signal to be found in the data from both LIGO observatories, according to a set of coincidence criteria. No inspiral signals were found. Assuming a spherical halo with core radius 5 kpc extending to 50 kpc containing non-spinning black holes with masses in the range 0.2--$1.0 M_\odot$, we place an observational upper limit on the rate of PBH coalescence of 63 per year per Milky Way halo (MWH) with 90% confidence.Comment: 7 pages, 4 figures, to be submitted to Phys. Rev.

Improving the sensitivity to gravitational-wave sources by modifying the input-output optics of advanced interferometers

We study frequency dependent (FD) input-output schemes for signal-recycling interferometers, the baseline design of Advanced LIGO and the current configuration of GEO 600. Complementary to a recent proposal by Harms et al. to use FD input squeezing and ordinary homodyne detection, we explore a scheme which uses ordinary squeezed vacuum, but FD readout. Both schemes, which are sub-optimal among all possible input-output schemes, provide a global noise suppression by the power squeeze factor, while being realizable by using detuned Fabry-Perot cavities as input/output filters. At high frequencies, the two schemes are shown to be equivalent, while at low frequencies our scheme gives better performance than that of Harms et al., and is nearly fully optimal. We then study the sensitivity improvement achievable by these schemes in Advanced LIGO era (with 30-m filter cavities and current estimates of filter-mirror losses and thermal noise), for neutron star binary inspirals, and for narrowband GW sources such as low-mass X-ray binaries and known radio pulsars. Optical losses are shown to be a major obstacle for the actual implementation of these techniques in Advanced LIGO. On time scales of third-generation interferometers, like EURO/LIGO-III (~2012), with kilometer-scale filter cavities, a signal-recycling interferometer with the FD readout scheme explored in this paper can have performances comparable to existing proposals. [abridged]Comment: Figs. 9 and 12 corrected; Appendix added for narrowband data analysi

Searching for gravitational waves from known pulsars

We present upper limits on the amplitude of gravitational waves from 28 isolated pulsars using data from the second science run of LIGO. The results are also expressed as a constraint on the pulsars' equatorial ellipticities. We discuss a new way of presenting such ellipticity upper limits that takes account of the uncertainties of the pulsar moment of inertia. We also extend our previous method to search for known pulsars in binary systems, of which there are about 80 in the sensitive frequency range of LIGO and GEO 600.Comment: Accepted by CQG for the proceeding of GWDAW9, 7 pages, 2 figure

Setting upper limits on the strength of periodic gravitational waves from PSR J1939+2134 using the first science data from the GEO 600 and LIGO detectors

Data collected by the GEO 600 and LIGO interferometric gravitational wave detectors during their first observational science run were searched for continuous gravitational waves from the pulsar J1939+2134 at twice its rotation frequency. Two independent analysis methods were used and are demonstrated in this paper: a frequency domain method and a time domain method. Both achieve consistent null results, placing new upper limits on the strength of the pulsar's gravitational wave emission. A model emission mechanism is used to interpret the limits as a constraint on the pulsar's equatorial ellipticity

First upper limits from LIGO on gravitational wave bursts

We report on a search for gravitational wave bursts using data from the first science run of the LIGO detectors. Our search focuses on bursts with durations ranging from 4 ms to 100 ms, and with significant power in the LIGO sensitivity band of 150 to 3000 Hz. We bound the rate for such detected bursts at less than 1.6 events per day at 90% confidence level. This result is interpreted in terms of the detection efficiency for ad hoc waveforms (Gaussians and sine-Gaussians) as a function of their root-sum-square strain h_{rss}; typical sensitivities lie in the range h_{rss} ~ 10^{-19} - 10^{-17} strain/rtHz, depending on waveform. We discuss improvements in the search method that will be applied to future science data from LIGO and other gravitational wave detectors.Comment: 21 pages, 15 figures, accepted by Phys Rev D. Fixed a few small typos and updated a few reference