2,101 research outputs found

    Governance, Deterrence, and National Homicide Rate

    Get PDF
    By extending the deterrence theory to national level the current study tested the hypothesis that ineffective government is largely responsible for higher homicide rate in a nation The homicide data required for the test were collected from the World Health Organization and the information on governance from the World Bank s World Governance Indicators for 122 nations The results from the regression models supported the deterrence theory An ineffective and dysfunctional government was one of the primary sources for a nation s high homicide rate Also other control variables such as relative poverty and ethnic heterogeneity were positively related to the homicide rate in a natio

    The stransverse mass, MT2, in special cases

    Full text link
    This document describes some special cases in which the stransverse mass, MT2, may be calculated by non-iterative algorithms. The most notable special case is that in which the visible particles and the hypothesised invisible particles are massless -- a situation relevant to its current usage in the Large Hadron Collider as a discovery variable, and a situation for which no analytic answer was previously known. We also derive an expression for MT2 in another set of new (though arguably less interesting) special cases in which the missing transverse momentum must point parallel or anti parallel to the visible momentum sum. In addition, we find new derivations for already known MT2 solutions in a manner that maintains manifest contralinear boost invariance throughout, providing new insights into old results. Along the way, we stumble across some unexpected results and make conjectures relating to geometric forms of M_eff and H_T and their relationship to MT2.Comment: 11 pages, no figures. v2 corrects minor typos. v3 corrects an incorrect statement in footnote 8 and inserts a missing term in eq (3.9). v4 and v5 correct minor typos spotted by reader

    Supersymmetric particle mass measurement with the boost-corrected contransverse mass

    Get PDF
    A modification to the contransverse mass (MCT) technique for measuring the masses of pair-produced semi-invisibly decaying heavy particles is proposed in which MCT is corrected for non-zero boosts of the centre-of-momentum (CoM) frame of the heavy states in the laboratory transverse plane. Lack of knowledge of the mass of the CoM frame prevents exact correction for this boost, however it is shown that a conservative correction can nevertheless be derived which always generates an MCT value which is less than or equal to the true value of MCT in the CoM frame. The new technique is demonstrated with case studies of mass measurement with fully leptonic ttbar events and with SUSY events possessing a similar final state.Comment: 33 pages, 33 .eps figures, JHEP3 styl

    ATTITUDES AND THE PRACTICE OF DOCUMENTATION OF INDIGENOUS KNOWLEDGE BY THE TRADITIONAL HEALTH PRACTITIONERS IN KWARA STATE, NIGERIA.

    Get PDF
    This paper examines the attitudes and the practice of documentation of indigenous knowledge by the traditional health practitioners (THP) in Kwara State, Nigeria. Indigenous knowledge has been playing significant roles most especially in the primary health of the people in rural areas. This important knowledge is prone to attrition due to non-documentation and the World Bank has warned that if the knowledge is not documented, it will be lost. The study adopted descriptive survey research design and utilized questionnaire to collect data for the study. 30 traditional health practitioners were purposively selected based on their experience for the study. Simple percentage and frequency count were used to analyse the biographic variables while the research questions were answered using means and standard deviation while the hypotheses were tested using Pearson Correlation. The result of the study shows that there were more male traditional health practitioners than female, the higher percentage of them were elderly and highly experienced in the practice. The practitioners had positive attitudes to documentation of their IK and there is significant relationship between attitudes and documentation of IK. Writing and storytelling are the most prominent practice of documentation and that lock of formal education, fear of loss of ownership of the knowledge, misuse of the documented knowledge among others are challenges facing documentation of Ik in Kwara State, Nigeria. The study concludes that THP should be helped to overcome these challenges so that they will be encouraged to document their IK to prevent it from going into extinction

    Reducing combinatorial uncertainties: A new technique based on MT2 variables

    Get PDF
    We propose a new method to resolve combinatorial ambiguities in hadron collider events involving two invisible particles in the final state. This method is based on the kinematic variable MT2 and on the MT2-assisted-on-shell reconstruction of invisible momenta, that are reformulated as `test' variables Ti of the correct combination against the incorrect ones. We show how the efficiency of the single Ti in providing the correct answer can be systematically improved by combining the different Ti and/or by introducing cuts on suitable, combination-insensitive kinematic variables. We illustrate our whole approach in the specific example of top anti-top production, followed by a leptonic decay of the W on both sides. However, by construction, our method is also directly applicable to many topologies of interest for new physics, in particular events producing a pair of undetected particles, that are potential dark-matter candidates. We finally emphasize that our method is apt to several generalizations, that we outline in the last sections of the paper.Comment: 1+23 pages, 8 figures. Main changes in v3: (1) discussion at the end of sec. 2 improved; (2) added sec. 4.2 about the method's dependence on mass information. Matches journal versio

    Sqrt{shat}_{min} resurrected

    Full text link
    We discuss the use of the variable sqrt{shat}_{min}, which has been proposed in order to measure the hard scale of a multi parton final state event using inclusive quantities only, on a SUSY data sample for a 14 TeV LHC. In its original version, where this variable was proposed on calorimeter level, the direct correlation to the hard scattering scale does not survive when effects from soft physics are taken into account. We here show that when using reconstructed objects instead of calorimeter energy and momenta as input, we manage to actually recover this correlation for the parameter point considered here. We furthermore discuss the effect of including W + jets and t tbar+jets background in our analysis and the use of sqrt{shat}_{min} for the suppression of SM induced background in new physics searches.Comment: 23 pages, 9 figures; v2: 1 figure, several subsections and references as well as new author affiliation added. Corresponds to published versio

    General analysis of signals with two leptons and missing energy at the Large Hadron Collider

    Full text link
    A signal of two leptons and missing energy is challenging to analyze at the Large Hadron Collider (LHC) since it offers only few kinematical handles. This signature generally arises from pair production of heavy charged particles which each decay into a lepton and a weakly interacting stable particle. Here this class of processes is analyzed with minimal model assumptions by considering all possible combinations of spin 0, 1/2 or 1, and of weak iso-singlets, -doublets or -triplets for the new particles. Adding to existing work on mass and spin measurements, two new variables for spin determination and an asymmetry for the determination of the couplings of the new particles are introduced. It is shown that these observables allow one to independently determine the spin and the couplings of the new particles, except for a few cases that turn out to be indistinguishable at the LHC. These findings are corroborated by results of an alternative analysis strategy based on an automated likelihood test.Comment: 18 pages, 3 figures, LaTe
    corecore