2,718 research outputs found

    Fine-tuning implications for complementary dark matter and LHC SUSY searches

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    The requirement that SUSY should solve the hierarchy problem without undue fine-tuning imposes severe constraints on the new supersymmetric states. With the MSSM spectrum and soft SUSY breaking originating from universal scalar and gaugino masses at the Grand Unification scale, we show that the low-fine-tuned regions fall into two classes that will require complementary collider and dark matter searches to explore in the near future. The first class has relatively light gluinos or squarks which should be found by the LHC in its first run. We identify the multijet plus E_T^miss signal as the optimal channel and determine the discovery potential in the first run. The second class has heavier gluinos and squarks but the LSP has a significant Higgsino component and should be seen by the next generation of direct dark matter detection experiments. The combined information from the 7 TeV LHC run and the next generation of direct detection experiments can test almost all of the CMSSM parameter space consistent with dark matter and EW constraints, corresponding to a fine-tuning not worse than 1:100. To cover the complete low-fine-tuned region by SUSY searches at the LHC will require running at the full 14 TeV CM energy; in addition it may be tested indirectly by Higgs searches covering the mass range below 120 GeV.Comment: References added. Version accepted for publication in JHE

    Tuning supersymmetric models at the LHC: A comparative analysis at two-loop level

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    We provide a comparative study of the fine tuning amount (Delta) at the two-loop leading log level in supersymmetric models commonly used in SUSY searches at the LHC. These are the constrained MSSM (CMSSM), non-universal Higgs masses models (NUHM1, NUHM2), non-universal gaugino masses model (NUGM) and GUT related gaugino masses models (NUGMd). Two definitions of the fine tuning are used, the first (Delta_{max}) measures maximal fine-tuning wrt individual parameters while the second (Delta_q) adds their contribution in "quadrature". As a direct result of two theoretical constraints (the EW minimum conditions), fine tuning (Delta_q) emerges as a suppressing factor (effective prior) of the averaged likelihood (under the priors), under the integral of the global probability of measuring the data (Bayesian evidence p(D)). For each model, there is little difference between Delta_q, Delta_{max} in the region allowed by the data, with similar behaviour as functions of the Higgs, gluino, stop mass or SUSY scale (m_{susy}=(m_{\tilde t_1} m_{\tilde t_2})^{1/2}) or dark matter and g-2 constraints. The analysis has the advantage that by replacing any of these mass scales or constraints by their latest bounds one easily infers for each model the value of Delta_q, Delta_{max} or vice versa. For all models, minimal fine tuning is achieved for M_{higgs} near 115 GeV with a Delta_q\approx Delta_{max}\approx 10 to 100 depending on the model, and in the CMSSM this is actually a global minimum. Due to a strong (\approx exponential) dependence of Delta on M_{higgs}, for a Higgs mass near 125 GeV, the above values of Delta_q\approx Delta_{max} increase to between 500 and 1000. Possible corrections to these values are briefly discussed.Comment: 23 pages, 46 figures; references added; some clarifications (section 2

    Palliative care in the USA and England: a critical analysis of meaning and implementation towards a public health approach

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    Delivering optimal and equitable palliative care is an international challenge. There are few cross-national comparisons examining challenges in expanding palliative care along public health lines. This paper presents a critical review of palliative care in the USA and England, which share similar challenges but have different contexts of healthcare. Beyond some obvious differences in the organisation of palliative care, a set of underlying common issues can be identified. A key tension in both is balancing attention ‘downstream’ in the dying phase, as well as ‘upstream’ earlier in the course of serious illness. In both, the dominant models of palliative care provision have resulted in excellent care towards the end of life for some patients, but there remain major deficiencies in care for the majority. England has a National Strategy for End-of-life care; the US has no equivalent, although a number of influential agencies have published statements. Achieving a public health approach in palliative care requires international consensus on the meaning and target population of palliative care, replacement of prognosis based understandings of entitlement to palliative care with a needs-based approach and development of an evidence base for cost-effective partnerships between providers across the specialist–generalist divide

    Conservative upper limits on WIMP annihilation cross section from Fermi-LAT γ\gamma-rays

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    The spectrum of an isotropic extragalactic γ\gamma-ray background (EGB) has been measured by the Fermi-LAT telescope at high latitudes. Two new models for the EGB are derived from the subtraction of unresolved point sources and extragalactic diffuse processes, which could explain from 30% to 70% of the Fermi-LAT EGB. Within the hypothesis that the two residual EGBs are entirely due to the annihilation of dark matter (DM) particles in the Galactic halo, we obtain conservativeconservative upper limits on their annihilation cross section \sigmav. Severe bounds on a possible Sommerfeld enhancement of the annihilation cross section are set as well. Finally, would {\sigmav} be inversely proportional to the WIMP velocity, very severe limits are derived for the velocity-independent part of the annihilation cross section.Comment: Proceedings of XII Taup Conference, Munich, September 201

    Comparing antibody responses to Onchocerca volvulus and non-parasite antigens in placebo-controlled and ivermectin-treated onchocerciasis patients

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    Serum antibodies to parasite-specific and non-parasite antigens were evaluated  using enzyme-linked immunosorbent assay (ELISA). Out of the 470 sera collected, 409 were from residents of an onchocerciasis hyper-endemic area, 55 non-endemic and 6 European normal sera served as control. The patients’ age, sex, skin  microfilaria densities, dermal and ocular clinical manifestations (colour of optic disc) have been well characterised. The study population had participated in a  placebocontrolled (n=191) trial of ivermectin (Mectizan®) treatment (n=218). The parasite antigens are phosphate buffered saline crude extract of adult worms of Onchocerca volvulus, a recombinant antigen (Ov1.9) and a monoclonal antibody purified antigen (Cam 1). The non-parasite antigens are deoxycholate citrate extract of optic nerve (nerve-DOC) and commercially available IgA, IgM and IgG were used to assay for rheumatoid factor (Rh-F) auto-antibodies. Generally, antibodies to parasite antigens in onchocerciasis patients were remarkably higher than control group (p<0.05) using exact F-test. There was no significant difference (p>0.05) in antibodies to nerve-DOC and Rh-F in patients compared to control. Antibodies increased with increasing skin snip microfilaria load from 0.69±0.28 with 0mf/mg (n=54) as against 0.80±0.26 for those with 4-20mf/mg. Observed slight negative correlation in IgG antibody levels and severity of disc colour with mean OD values of 0.26±0.22 in those graded as having no optic nerve disease (OND) (disc 1, n=86) and 0.17±0.19 for those with severe changes (disc 3, n=49) was not statistically significant (P>0.05). An age dependent significant decrease (P<0.05) in antibodies were observed with 0.64±0.34 for 15-30yr old (n=48) compared to 0.48±0.35 for those 50yr (n=50) for PBS with a similar trend for IgG to Ov1.9 and Cam1. In conclusion, serum parasite-specific and non-parasite antibodies may not be responsible for the pathology of optic nerve disease. Onchocerciasis patients were apparently not at higher risk of developing rheumatoid arthritis than the control.Keywords: Onchocerciasis; Antibodies; Antigens; Immune responses; Ivermectin

    Naturalness and Fine Tuning in the NMSSM: Implications of Early LHC Results

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    We study the fine tuning in the parameter space of the semi-constrained NMSSM, where most soft Susy breaking parameters are universal at the GUT scale. We discuss the dependence of the fine tuning on the soft Susy breaking parameters M_1/2 and m0, and on the Higgs masses in NMSSM specific scenarios involving large singlet-doublet Higgs mixing or dominant Higgs-to-Higgs decays. Whereas these latter scenarios allow a priori for considerably less fine tuning than the constrained MSSM, the early LHC results rule out a large part of the parameter space of the semi-constrained NMSSM corresponding to low values of the fine tuning.Comment: 19 pages, 10 figures, bounds from Susy searches with ~1/fb include

    Epidemiology of Sexually Transmitted Infections in Visitors for the London 2012 Olympic Games: A Review of Attendees at Sexual Health Services

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    BACKGROUND: Mass gatherings and large sporting events, such as the Olympics, may potentially pose a risk of increased sexually transmitted infection (STI) transmission and increase burden on local STI services. The objectives of this analysis were to assess whether the STI profile of Olympic visitors differed from that of the local STI clinic population and to investigate what impact these visitors had on local STI services. METHODS: Self-administered questionnaires (completed by 29,292 patients) were used to determine the visitor status of patients attending 20 STI clinics, between July 20, 2012, and September 16, 2012, in the host cities, London and Weymouth. Using routine surveillance data from the Genitourinary Medicine Clinic Activity Dataset version 2, Olympic visitors were compared with usual attendees (local residents and non-Olympic visitors) in terms of their demographic characteristics, services utilized, and STIs diagnosed using univariate and multivariate methods. RESULTS: Compared with usual attendees, Olympic visitors were more likely to be heterosexual males (56.0% vs. 34.9%, P = 0.001), aged between 15 and 24 years of age (47.1% vs. 34.0%, P = 0.001), of white ethnicity (81.9% vs. 66.4%, P = 0.001), and born in Australasia, Asia, North America, or South America (18.8% vs. 12.0%, P = 0.006). Olympic visitors constituted 1% of new clinic attendances and were less likely to be diagnosed as having a new STI (adjusted odds ratio, 0.69; 95% confidence interval, 0.48–0.98; P = 0.040). CONCLUSIONS: In this first multisite study to examine the effect of Olympic visitors on local sexual health services, the 2012 Olympic Games was found to have minimal impact. This suggests that a “business as usual” approach would have been sufficient

    Double Exponential Instability of Triangular Arbitrage Systems

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    If financial markets displayed the informational efficiency postulated in the efficient markets hypothesis (EMH), arbitrage operations would be self-extinguishing. The present paper considers arbitrage sequences in foreign exchange (FX) markets, in which trading platforms and information are fragmented. In Kozyakin et al. (2010) and Cross et al. (2012) it was shown that sequences of triangular arbitrage operations in FX markets containing 4 currencies and trader-arbitrageurs tend to display periodicity or grow exponentially rather than being self-extinguishing. This paper extends the analysis to 5 or higher-order currency worlds. The key findings are that in a 5-currency world arbitrage sequences may also follow an exponential law as well as display periodicity, but that in higher-order currency worlds a double exponential law may additionally apply. There is an "inheritance of instability" in the higher-order currency worlds. Profitable arbitrage operations are thus endemic rather that displaying the self-extinguishing properties implied by the EMH.Comment: 22 pages, 22 bibliography references, expanded Introduction and Conclusion, added bibliohraphy reference

    Z' Boson Mixings with Z-\gamma and Charge Assignments

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    Based on the general description for Z'-Z-\gamma mixing as derived from the electroweak chiral Lagrangian, we characterize and classify the various new physics models involving the Z' boson that have appeared in the literature into five classes: 1. Models with minimal Z'-Z mass mixing; 2. Models with minimal Z'-Z kinetic mixing; 3. Models with general Z'-Z mixing; 4. Models with Z'-\gamma kinetic and Z'-Z mixing; and 5. Models with Stueckelberg-type mixing. The corresponding mixing matrices are explicitly evaluated for each of these classes. We constrain and classify the Z' boson charges with respect to quark-leptons by anomaly cancellation conditions.Comment: 17 page
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