299,888 research outputs found
Mapping The Neutrino Floor For Dark Matter-Electron Direct Detection Experiments
We study the discovery reach of future Dark Matter (DM) Direct Detection
experiments using DM-electron scattering in the presence of the solar neutrino
background. At these low energies traditional methods for nuclear and
electronic recoil discrimination fail, implying that the neutrino-{\it nucleus}
scattering background can be sizable. We calculate discovery limits based on
ionization values of signal and background, and quantify the dependence on the
ionization model. Moreover, we explore how the dependence of the DM cross
section discovery limits vary with exposure, electronic/nuclear recoil
discrimination, DM form factors, and DM astrophysical uncertainties.Comment: 10 pages, 9 figure
Prospects for discovery and spin discrimination of dark matter in Higgs portal DM models and their extensions at 100 TeV collider
We study the discovery and discriminating prospects of the Higgs portal dark
matter (DM) models for scalar, fermion and vector DM and their extensions in
proton-proton () collisions. The DM associated production in
dileptonic final states is considered, in which the stransverse mass of two
leptons is found to be effective in suppressing the Standard Model backgrounds
along with the missing transverse energy and the angle between two leptons. The
distributions of missing transverse energy and polar angle between two leptons
are used for a discrimination of the spin nature of DM. For the proposed
benchmark points, the discovery/exclusion can be made with an integrated
luminosity less than 1 ab given a 1\% systematic uncertainty, while the
spin discrimination require integrated luminosity of a few O(10) ab
given a 0.5\% systematic uncertainty. The DM phenomenology is also discussed. A
consistent DM candidate can be obtained either by extending our model where the
Higgs portal couples to excited dark states that decay into DM, or modifying
the coupling form into pseudoscalar.Comment: 25 pages, 13 figures; discussions of systematic uncertainty added;
matches the published versio
Search for Heavy Sterile Neutrinos in Trileptons at the LHC
We present a search strategy for both Dirac and Majorana sterile neutrinos
from the purely leptonic decays of and
at the 14 TeV LHC. The discovery and exclusion
limits for sterile neutrinos are shown using both the Cut-and-Count (CC) and
Multi-Variate Analysis (MVA) methods. We also discriminate between Dirac and
Majorana sterile neutrinos by exploiting a set of kinematic observables which
differ between the Dirac and Majorana cases. We find that the MVA method,
compared to the more common CC method, can greatly enhance the discovery and
discrimination limits. Two benchmark points with sterile neutrino mass GeV and 50 GeV are tested. For an integrated luminosity of 3000 , sterile neutrinos can be found with significance if
heavy-to-light neutrino mixings ,
while Majorana vs. Dirac discrimination can be reached if at least one of the
mixings is of order .Comment: 4 pages, 6 figures. arXiv admin note: substantial text overlap with
arXiv:1703.0193
Ligand-based virtual screening using binary kernel discrimination
This paper discusses the use of a machine-learning technique called binary kernel discrimination (BKD) for virtual screening in drug- and pesticide-discovery programmes. BKD is compared with several other ligand-based tools for virtual screening in databases of 2D structures represented by fragment bit-strings, and is shown to provide an effective, and reasonably efficient, way of prioritising compounds for biological screening
Higgs look-alikes at the LHC
The discovery of a Higgs particle is possible in a variety of search channels
at the LHC. However the true identity of any putative Higgs boson will at first
remain ambiguous, until one has experimentally excluded other possible
assignments of quantum numbers and couplings. We quantify to what degree one
can discriminate a Standard Model Higgs boson from "look-alikes" at, or close
to, the moment of discovery at the LHC. We focus on the fully-reconstructible
"golden" decay mode to a pair of Z bosons and a four-lepton final state,
simulating sPlot-weighted samples of signal and background events. Considering
both on-shell and off-shell Z's, we show how to utilize the full decay
information from the events, including the distributions and correlations of
the five relevant angular variables. We demonstrate how the finite phase space
acceptance of any LHC detector sculpts the decay distributions, a feature
neglected in previous studies. We use likelihood ratios to discriminate a
Standard Model Higgs from look-alikes with other spins or nonstandard parity,
CP, or form factors. For a benchmark resonance mass of 200 GeV/c^2, we achieve
a median expected discrimination significance of 3 sigma with as few as 19
events, and even better discrimination for the off-shell decays of a 145
GeV/c^2 resonance.Comment: 39 pages, 55 figures, typos fixed, figures added, and minor
clarification
Mapping the Neutrino Floor for Direct Detection Experiments Based on Dark Matter-Electron Scattering
We study the discovery reach of future Dark Matter (DM) Direct Detection experiments using DM-electron scattering in the presence of the solar neutrino background. At these low energies traditional methods for nuclear and electronic recoil discrimination fail, implying that the neutrino- nucleusscattering background can be sizable. We calculate discovery limits based on ionization values of signal and background, and quantify the dependence on the ionization model. Moreover, we explore how the dependence of the DM cross section discovery limits varies with exposure, electronic/nuclear recoil discrimination, DM form factors, and DM astrophysical uncertainties
Probing TeV scale Top-Philic Resonances with Boosted Top-Tagging at the High Luminosity LHC
We investigate the discovery potential of singly produced top-philic
resonances at the high luminosity (HL) LHC in the four-top final state. Our
analysis spans over the fully-hadronic, semi-leptonic, and same-sign dilepton
channels where we present concrete search strategies adequate to a boosted
kinematic regime and high jet-multiplicity environments. We utilize the
Template Overlap Method (TOM) with newly developed template observables for
tagging boosted top quarks, a large-radius jet variable and customized
b-tagging tactics for background discrimination. Our results show that the
same-sign dilepton channel gives the best sensitivity among the considered
channels, with an improvement of significance up to 10%-20% when combined with
boosted-top tagging. Both the fully-hadronic and semi-leptonic channels yield
comparable discovery potential and contribute to further enhancements in the
sensitivity by combining all channels. Finally, we show the sensitivity of a
top-philic resonance at the LHC and HL-LHC by showing the exclusion
limit and discovery reach, including a combination of all three
channels.Comment: 19 pages, 14 figure
Discovering Racial Discrimination by the Police
For decades, it was virtually impossible for a criminal defendant to challenge racial discrimination by the police or prosecutors. This was because in United States v. Armstrong, 517 U.S. 456 (1996), the Supreme Court set an insurmountable standard for obtaining discovery in support of a selective prosecution claim. Equating the roles of prosecutors and law enforcement officers, lower courts applied this same standard to claims alleging racial discrimination by the police. This high standard led courts to deny discovery and stifle potentially meritorious claims. Recently, criminal defendants have initiated a wave of challenges to âfake stash houseâ operations, in which federal law enforcement agencies like the ATF and the DEA approach peopleâoverwhelmingly people of colorâand induce them to rob a nonexistent drug stash house. Defense attorneys have argued that these practices constitute racially selective law enforcement and that Armstrongâs strict standard should not apply to the police. Three federal courts of appeals responded by recognizing that the differences between prosecutors and law enforcement officers merit lowering the discovery standard for defendants alleging racial discrimination by the police. This Article is the first to describe and defend this important development in equal protection jurisprudence. We argue that other courts should similarly craft a lower discovery standard.
Recognizing that federal courts hear only a fraction of race discrimination claims, this Article embraces the spirit of federalism and proposes an innovative state-level solution: a state court rule lowering the insuperable discovery standard to which most states still cling. This Article draws on a recent Washington state court rule aimed at preventing racial discrimination in jury selection to propose that state courts adopt a similar rule setting a new discovery standard for racially selective law enforcement claims. Such a rule would ensure that state-level equal protection claims are not blocked at the discovery stage, thus enabling courts to adjudicate those claims on the merits
The brattleboro rat displays a natural deficit in social discrimination that is restored by clozapine and a neurotensin analog.
Cognitive deficits in schizophrenia are a major source of dysfunction for which more effective treatments are needed. The vasopressin-deficient Brattleboro (BRAT) rat has been shown to have several natural schizophrenia-like deficits, including impairments in prepulse inhibition and memory. We investigated BRAT rats and their parental strain, Long-Evans (LE) rats, in a social discrimination paradigm, which is an ethologically relevant animal test of cognitive deficits of schizophrenia based upon the natural preference of animals to investigate conspecifics. We also investigated the effects of the atypical antipsychotic, clozapine, and the putative antipsychotic, PD149163, a brain-penetrating neurotensin-1 agonist, on social discrimination in these rats. Adult rats were administered saline or one of the three doses of clozapine (0.1, 1.0, or 10 mg/kg) or PD149163 (0.1, 0.3, or 1.0 mg/kg), subcutaneously. Following drug administration, adult rats were exposed to a juvenile rat for a 4-min learning period. Animals were then housed individually for 30 min and then simultaneously exposed to the juvenile presented previously and a new juvenile for 4 min. Saline-treated LE rats, but not BRAT rats, exhibited intact social discrimination as evidenced by greater time spent exploring the new juvenile. The highest dose of clozapine and the two highest doses of PD149163 restored social discrimination in BRAT rats. These results provide further support for the utility of the BRAT rat as a genetic animal model relevant to schizophrenia and drug discovery. The potential of neurotensin agonists as putative treatments for cognitive deficits of schizophrenia was also supported
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