A Measurement of the Cosmic Ray Spectrum and Composition at the Knee

The energy spectrum and primary composition of cosmic rays with energy between $3\times 10^{14}$ and 3\times10^{16}\unit{eV} have been studied using the CASA-BLANCA detector. CASA measured the charged particle distribution of air showers, while BLANCA measured the lateral distribution of Cherenkov light. The data are interpreted using the predictions of the CORSIKA air shower simulation coupled with four different hadronic interaction codes. The differential flux of cosmic rays measured by BLANCA exhibits a knee in the range of 2--3 PeV with a width of approximately 0.5 decades in primary energy. The power law indices of the differential flux below and above the knee are $-2.72\pm0.02$ and $-2.95\pm0.02$. We present our data both as a mean depth of shower maximum and as a mean nuclear mass. A multi-component fit using four elemental species shows the same composition trends given by the mean quantities, and also indicates that QGSJET and VENUS are the preferred hadronic interaction models. We find that an initially mixed composition turns lighter between 1 and 3 PeV, and then becomes heavier with increasing energy above 3 PeV.Comment: 25 pages, 10 figures. Submitted to Astroparticle Physic

Calcium-loaded hydrophilic hypercrosslinked polymers for extremely high defluoridation capacity via multiple uptake mechanisms

Hydrophilic hypercrosslinked porous polymer networks were synthesised from 2,2-biphenol (HHCP1) and bisphenol A (HHCP2) monomers, which were assessed for remediation of highly fluoridated water. The networks were hydrophilic and the hypercrosslinking radically altered the acidity of protonation sites within the polymeric scaffolds. The polymers were metallated to produce novel, hybrid Ca-loaded adsorbents. The metal-loading affected the electron distribution of the quinonoid structures formed during polymerisation. HHCP1 had a greater exchange capacity (6.34 ± 0.17 mmol g−1) and adsorbed more Ca2+, yet retained much of its original surface area, whereas HHCP2 was rendered non-porous upon metallation. Ca-loading included covalent interactions and formation of crystalline CaCO3 (vaterite), from preferential CO2 binding under ambient conditions. Both networks were effective defluoridating media, with Ca-loaded HHCP1 exhibiting a capacity among the highest yet reported for any extractant (267 ± 34 mg g−1). HHCP2-Ca had a lower capacity of 96.2 ± 10 mg g−1, but faster uptake kinetics and was more effective at lower concentrations, attributed to stronger binding interactions. Crystalline CaF2 (fluorite) was the dominant fluoride species formed, from both vaterite and covalently bound Ca. The networks could be used in a dynamic column system, extracted fluoride in the presence of multiple coexisting anions and were regenerable, with a potential pathway demonstrated for recovery of the adsorbed fluoride

Examining the Higgs boson potential at lepton and hadron colliders: a comparative analysis

We investigate inclusive Standard Model Higgs boson pair production at lepton and hadron colliders for Higgs boson masses in the range 120 GeV < m_H < 200 GeV. For m_H < 140 GeV we find that hadron colliders have a very limited capability to determine the Higgs boson self-coupling, \lambda, due to an overwhelming background. We also find that, in this mass range, supersymmetric Higgs boson pairs may be observable at the LHC, but a measurement of the self coupling will not be possible. For m_H > 140 GeV we examine ZHH and HH nu bar-nu production at a future e+e- linear collider with center of mass energy in the range of sqrt{s}=0.5 - 1 TeV, and find that this is likely to be equally difficult. Combining our results with those of previous literature, which has demonstrated the capability of hadron and lepton machines to determine \lambda in either the high or the low mass regions, we establish a very strong complementarity of these machines.Comment: Revtex, 25 pages, 2 tables, 10 figure

Determining the Higgs Boson Self Coupling at Hadron Colliders

Inclusive Standard Model Higgs boson pair production at hadron colliders has the capability to determine the Higgs boson self-coupling, lambda. We present a detailed analysis of the gg\to HH\to (W^+W^-)(W^+W^-)\to (jjl^\pm\nu)(jj{l'}^\pm\nu) and gg\to HH\to (W^+W^-)(W^+W^-)\to (jjl^\pm\nu)({l'}^\pm\nu {l''}^\mp\nu) (l, {l'}, {l''}=e, \mu) signal channels, and the relevant background processes, for the CERN Large Hadron Collider, and a future Very Large Hadron Collider operating at a center-of-mass energy of 200 TeV. We also derive quantitative sensitivity limits for lambda. We find that it should be possible at the LHC with design luminosity to establish that the Standard Model Higgs boson has a non-zero self-coupling and that lambda / lambda_{SM} can be restricted to a range of 0-3.8 at 95% confidence level (CL) if its mass is between 150 and 200 GeV. At a 200 TeV collider with an integrated luminosity of 300 fb^{-1}, lambda can be determined with an accuracy of 8 - 25% at 95% CL in the same mass range.Comment: 28 pages, Revtex3, 9 figures, 3 table

Quenched Lattice QCD with Domain Wall Fermions and the Chiral Limit

Quenched QCD simulations on three volumes, $8^3 \times$, $12^3 \times$ and $16^3 \times 32$ and three couplings, $\beta=5.7$, 5.85 and 6.0 using domain wall fermions provide a consistent picture of quenched QCD. We demonstrate that the small induced effects of chiral symmetry breaking inherent in this formulation can be described by a residual mass (\mres) whose size decreases as the separation between the domain walls ($L_s$) is increased. However, at stronger couplings much larger values of $L_s$ are required to achieve a given physical value of \mres. For $\beta=6.0$ and $L_s=16$, we find \mres/m_s=0.033(3), while for $\beta=5.7$, and $L_s=48$, \mres/m_s=0.074(5), where $m_s$ is the strange quark mass. These values are significantly smaller than those obtained from a more naive determination in our earlier studies. Important effects of topological near zero modes which should afflict an accurate quenched calculation are easily visible in both the chiral condensate and the pion propagator. These effects can be controlled by working at an appropriately large volume. A non-linear behavior of $m_\pi^2$ in the limit of small quark mass suggests the presence of additional infrared subtlety in the quenched approximation. Good scaling is seen both in masses and in $f_\pi$ over our entire range, with inverse lattice spacing varying between 1 and 2 GeV.Comment: 91 pages, 34 figure

Changing practices: The specialised domestic violence court process

Specialised domestic violence courts, initially developed in the United States of America, have been recognised by other jurisdictions including Canada, Australia and the United Kingdom. This article presents a case study of K Court in Toronto, drawing upon documentary evidence, direct observations and interviews with key informants. It is argued that the specialised domestic violence court process includes changing practices of some of the key stakeholders. Learning lessons from abroad can offer jurisdictions insights that can steer implementation of appropriate practices in the field

Phenomenology of flavor-mediated supersymmetry breaking

The phenomenology of a new economical SUSY model that utilizes dynamical SUSY breaking and gauge-mediation (GM) for the generation of the sparticle spectrum and the hierarchy of fermion masses is discussed. Similarities between the communication of SUSY breaking through a messenger sector, and the generation of flavor using the Froggatt-Nielsen (FN) mechanism are exploited, leading to the identification of vector-like messenger fields with FN fields, and the messenger U(1) as a flavor symmetry. An immediate consequence is that the first and second generation scalars acquire flavor-dependent masses, but do not violate FCNC bounds since their mass scale, consistent with effective SUSY, is of order 10 TeV. We define and advocate a minimal flavor-mediated model (MFMM), recently introduced in the literature, that successfully accommodates the small flavor-breaking parameters of the standard model using order one couplings and ratios of flavon field vevs. The mediation of SUSY breaking occurs via two-loop log-enhanced GM contributions, as well as several one-loop and two-loop Yukawa-mediated contributions for which we provide analytical expressions. The MFMM is parameterized by a small set of masses and couplings, with values restricted by several model constraints and experimental data. The next-to-lightest sparticle (NLSP) always has a decay length that is larger than the scale of a detector, and is either the lightest stau or the lightest neutralino. Similar to ordinary GM models, the best collider search strategies are, respectively, inclusive production of at least one highly ionizing track, or events with many taus plus missing energy. In addition, D^0 - \bar{D}^0 mixing is also a generic low energy signal. Finally, the dynamical generation of the neutrino masses is briefly discussed.Comment: 54 pages, LaTeX, 8 figure

Psychological stress and other potential triggers for recurrences of herpes simplex virus eye infections

Objective To assess psychological stress and other factors as possible triggers of ocular herpes simplex virus (HSV) recurrences. Design A prospective cohort study nested in a randomized, placebo-controlled, clinical trial. Setting Fifty-eight community-based or university sites. Participants Immunocompetent adults (N = 308), aged 18 years or older, with a documented history of ocular HSV disease in the prior year and observed for up to 15 months. Exposure Variables Psychological stress, systemic infection, sunlight exposure, menstrual period, contact lens wear, and eye injury recorded on a weekly log. The exposure period was considered to be the week before symptomatic onset of a recurrence. Main Outcome Measure The first documented recurrence of ocular HSV disease, with exclusion of cases in which the exposure week log was completed late after the onset of symptoms. Results Thirty-three participants experienced a study outcome meeting these criteria. Higher levels of psychological stress were not associated with an increased risk of recurrence (rate ratio, 0.58; 95% confidence interval, 0.32-1.05; P = .07). No association was found between any of the other exposure variables and recurrence. When an analysis was performed including only the recurrences (n = 26) for which the exposure week log was completed late and after symptom onset, there was a clear indication of retrospective overreporting of high stress (P = .03) and systemic infection (P = .01). Not excluding these cases could have produced incorrect conclusions due to recall bias. Conclusions Psychological stress does not appear to be a trigger of recurrences of ocular HSV disease. If not accounted for, recall bias can substantially overestimate the importance of factors that do not have a causal association with HSV infection

The Fluorescence Detector of the Pierre Auger Observatory

The Pierre Auger Observatory is a hybrid detector for ultra-high energy cosmic rays. It combines a surface array to measure secondary particles at ground level together with a fluorescence detector to measure the development of air showers in the atmosphere above the array. The fluorescence detector comprises 24 large telescopes specialized for measuring the nitrogen fluorescence caused by charged particles of cosmic ray air showers. In this paper we describe the components of the fluorescence detector including its optical system, the design of the camera, the electronics, and the systems for relative and absolute calibration. We also discuss the operation and the monitoring of the detector. Finally, we evaluate the detector performance and precision of shower reconstructions.Comment: 53 pages. Submitted to Nuclear Instruments and Methods in Physics Research Section