31 July 2019 to 2 August 2019
Stockholm university
Europe/Stockholm timezone

Contribution List

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  1. Glen Cowan, Louis Lyons (Imperial College (GB))
    31/07/2019, 09:30

    These will review some simple statistical concepts that are relevant to this Workshop. Among other topics, it will include upper limits, p-values and likelihood ratios. It is intended for those who would like to be reminded of their Statistics, before the Workshop begins.

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  2. Jan Conrad
    31/07/2019, 11:30
    Talk

    Intro to workshop

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  3. Dr Jim Dobson
    31/07/2019, 11:40

    In this talk I will give an overview of the current status of recent and future direct detection experiments and outline the practices that have been adopted for statistical inference from data and for making sensitivity projections. I will then discuss why a common approach to the choice of test statistic, the procedure for switching from a discovery mode to signal characterization and the...

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  4. Felix Kahlhoefer (RWTH Aachen)
    31/07/2019, 12:10

    Direct detection experiments place some of the strongest constraints on models of dark matter and are therefore essential to include in global analyses of such models. In this talk I will discuss the specific requirements for and possible applications of likelihood functions from direct detection experiments. I will give a brief introduction into the public code DDCalc, which provides...

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  5. Maria Elena Monzani (Stanford University)
    31/07/2019, 14:30

    Direct detection experiments rely on a variety of bias mitigation strategies, most notably blinding and salting. I will review the main challenges and methods for blinding and salting, in preparation for the next generation of dark matter searches.

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  6. Dr Ben Loer (Pacific Northwest National Laboratory)
    31/07/2019, 15:00

    A variety of data blinding strategies have been adopted by different experiments searching for dark matter. I will present a brief overview of the relative strengths and weaknesses of some of the most common strategies, and describe the reasoning for and implementation of these methods by some leading dark matter experiments.

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  7. Dr Sara Algeri (University of Minnesota)
    31/07/2019, 15:30

    The look-elsewhere effect is a phenomenon which often arises when looking for signals whose location is not known in advance. In this setting, signal searches can be conducted by performing several tests of hypothesis at different positions over the search area considered. However, if the result of each individual test is not adequately adjusted for the fact that many tests are conducted...

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  8. Nicholas Wardle (Imperial College (GB))
    31/07/2019, 16:30

    The ATLAS and CMS collaborations have produced numerous results during the
    first two data-taking runs of the LHC, ranging from precision measurements of SM processes to searches for exotic phenomena and the dicovery of the Higgs boson. All of these results make use of sophisticated statistical techniques, not only to provide statistical inferences from the data, but also during the...

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  9. Matteo Agostini
    31/07/2019, 17:00
    Talk

    The neutrinoless double-beta decay is a hypothetical nuclear transition predicted by most of the theories that explain the origin of neutrino masses or the dominance of matter over antimatter in our Universe. The primary experimental signature for this transition is an excess of monoenergetic events. While the statistical problem can be traced back to the simple search for a peak over some...

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  10. Dr Hagar Landsmann (Weizmann Inst. of Science)
    31/07/2019, 17:30
    Talk

    In this talk, I will review the various methods, tools, tricks, and shortcuts used by various dark matter experiments to set upper limits on dark matter interaction cross-section. Focusing on the progression of the methods as the number of parameter increases and the background decreases I will discuss the big question of evolution vs. intelligent design (in the statistical inference realm J).

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  11. Dr Andrew Fowlie (Nanjing Normal University)
    31/07/2019, 18:05

    I discuss findings from my recent comparison of Bayesian and frequentist approaches to discoveries ([1902.03243][1]). I introduce a counting experiment in which we are searching for a signal in the presence of a background, from which I generate pseudo-data. With that pseudo-data, I contrast the evolution of the $p$-value and posterior as we accumulate data and directly compare global...

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  12. Dr Ianni Aldo (INFN - LNGS)
    31/07/2019, 18:05

    In 2018 DAMA/LIBRA has reported results about 6 more annual cycles, the so-called Phase-II, which follows an upgrade of the detector with respect to Phase-I. A combined frequentist analysis of the results of DAMA Phase I and II is presented. The combined analysis is compared with each individual Phase result with the same assumptions. A discussion of nuisance parameters is reported.

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  13. SHAUN ALSUM (University of Wisconsin-Madison)
    31/07/2019, 18:05

    LUX uses the hypothesis testing based on a profile likelihood ratio to determine the consistency of its data to a background only hypothesis, as well as to set confidence limits on the interaction strength of potential dark matter candidates.
    In this talk I will present on improvements made to the code base used for conduction these tests. The model generation is now streamlined based on...

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  14. Dr Young Ju Ko (Institute for Basic Science (IBS))
    31/07/2019, 18:05

    COSINE-100 is an experiment to detect dark matter induced recoil interactions in NaI(Tl) crystals in order to test the DAMA/LIBRA collaboration’s claim. The COSINE-100 detector has been operating since September of 2016 in the 700-m-deep Yangyang underground laboratory. First shape  and annual modulation analyses have been completed, and the related statistical approaches will be presented. In...

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  15. Dr Andrew Fowlie (Nanjing Normal University)
    31/07/2019, 18:05

    I introduce a new formalism for incorporating uncertainties in the velocity distribution of dark matter in direct detection experiments ([1809.02323][1]). The method constructs a prior over upon possible velocity distributions. The prior penalizes departures from our expectation (e.g., a Maxwellian) according to the relative entropy. The uncertainty is subsequently marginalized using an exact...

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  16. Ms Ashlea Kemp (Royal Holloway, University of London)
    31/07/2019, 18:05

    The DEAP-3600 detector based 2km underground at SNOLAB (Sudbury, Canada) is a dark matter direct detection experiment. The detector consists of a single-phase liquid argon (LAr) target, of 3279 kg mass. Currently, there have been two WIMP dark matter searches performed by the DEAP-3600 collaboration; for both results, a cut-and-count approach was employed. In this talk, the development of a...

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  17. Hau-Bin Li (Academia Sinica, Taipei, Taiwan)
    31/07/2019, 18:05

    we present results on light weakly interacting massive particles (WIMPs) searches with annual modulation (AM) analysis on data from a 1-kg mass p-type point-contact germanium detector of the CDEX-1B experiment at the China Jinping Underground Laboratory. Data set with a total live-time of 3.2 years within a 4.2-year span are analyzed with physics threshold of 250 eVee. Annual modulation limits...

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  18. Alessandra Brazzale
    01/08/2019, 09:00
    Talk

    I will review some classical methods of asymptotic inference and their higher order extensions. The focus will be on modern likelihood based solutions, though Bayesian counterparts will be mentioned in by-passing. The discussion will touch upon topics such as small sample sizes, large number of nuisance parameters, nonregular settings and complex models.

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  19. Igor Volobouev (Texas Tech University (US))
    01/08/2019, 09:30
    Talk

    We present a method for deriving signal significance p-values in the 5 sigma region for finite samples, to order O(n^{-3/2}), for a number of signal detection statistics (Wald, score, and likelihood ratio). Connection with the look elsewhere effect is discussed.

    The talk is based in part on the article by I. Volobouev and A. Trindade 2018 JINST 13 P12011

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  20. Dr Knut Dundas Morå
    01/08/2019, 10:00

    An experiment reporting only upper limits must allow the exclusion of arbitrarily low signals, and even the no-signal case if the confidence intervals are to cover.
    Many collaborations elect to avoid this, for example by using the CLs method to penalise downwards fluctuations, or by imposing a threshold below which signals are not excluded. In my presentation, I will review the two...

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  21. Dr Sara Algeri (University of Minnesota)
    01/08/2019, 11:00

    When searching for new astrophysical phenomena, uncertainty arising from background mismodelling can dramatically compromise the sensitivity of the experiment under study. Specifically, overestimating the background distribution in the signal region increases the chances of missing new physics. Conversely, underestimating the background outside the signal region leads to an artificially...

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  22. Dr Heather Battey (Imperial College London)
    01/08/2019, 11:30
    Talk

    I will speak about two aspects of partially specified models. The first of these arise from modelling explicitly only aspects of direct concern, retaining a degree of agnosticism over other aspects of the data generating process. I will illustrate with examples how this leads to a large number of nuisance parameters, and how these can be evaded in some situations. The second type of partially...

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  23. Robert Calkins (Southern Methodist University)
    01/08/2019, 14:00

    In order for an experiment to be able to claim discovery of a signal, it must first master its backgrounds and understand how a signal will manifest in the detector. The range of energies involved in the interactions tend to be low due to kinematics so much of an experiment's sensitivity is driven by its threshold. In this region, modeling the detector response can be difficult but I will...

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  24. Belina von Krosigk (University of Hamburg)
    01/08/2019, 14:30

    We have entered the era of single electron-hole pair sensitive crystal detectors with a threshold as low as the indirect band gap. These detectors are excellent devices to search for light dark sector particles with masses well below the threshold of to date typical direct Dark Matter search detectors. But with new opportunities come new challenges. New sources of background govern the...

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  25. Tina Pollmann (Technische Universität München)
    01/08/2019, 15:00
    Talk

    In many types of scintillator-based dark matter experiments, pulse shape discrimination (PSD) is used to mitigate backgrounds. The leakage probability of events mitigated through PSD into the region of interest (ROI) is an important parameter used to define the ROI and to inform the ROI background model. Determining the leakage probability requires an understanding of the distribution of...

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  26. Mr Daniel Durnford (University of Alberta)
    01/08/2019, 16:00
    Talk

    The statistical fluctuation of the number of e-/ion pairs produced in an ionizing interaction is known to be sub-Poissonian, the dispersion being reduced by the so-called “Fano Factor”. Due to a lack of appropriate modelling tools, this phenomenon is often folded into the overall energy response of ionization detectors. While this may be adequate down to relatively low-energies, this treatment...

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  27. MARTIN HOFERICHTER (University of Washington)
    02/08/2019, 09:00

    I will give an overview of the nuclear physics input required for the interpretation of direct detection searches for dark matter, concentrating on approaches based on chiral effective field theory.
    In particular, I will discuss the sources of uncertainty in the calculation of the nuclear responses, to trigger the discussion if and how to include these uncertainties in statistical analyses.

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  28. Dr Christopher McCabe (King's College London)
    02/08/2019, 09:35
    Talk

    The Gaia satellite is transforming our understanding of the distribution of dark matter in the Milky Way. I’ll discuss two structures that have recently been detected in the Milky Way, the S1 stellar stream and the Gaia Sausage, and their impact on experiments searching for the direct detection of dark matter.

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  29. Jan Kieseler (CERN)
    02/08/2019, 11:00
    Talk

    Machine Learning techniques have been employed in high energy physics already for decades, and have grown to be an important ingredient to event processing. This talk will focus on examples of recent applications and dedicated developments of advanced deep neural networks for particle reconstruction, identification and regression, as well as global event classification. Moreover, the talk will...

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  30. Luc Hendriks (Nikhef), Luc Hendriks
    02/08/2019, 11:30
    Talk

    Dark Machines is a research collective of about 200 physicists and data scientists, who use state-of-the-art machine learning techniques to solve dark matter related problems. These problems are typically organised as challenges: physicists provide datasets and the machine learning experts try to solve the problem in the best possible way. A few of the current focuses are particle track...

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  31. Robert Cousins Jr (University of California Los Angeles (US)), Robert Cousins Jr (University of California Los Angeles (US)), Robert Dacey Cousins Jr (Univ. of California Los Angeles (UCLA))
    02/08/2019, 13:30

    I will discuss aspects of the frequentist and Bayesian approaches to testing a point null hypothesis (say mu=0) versus a continuous alternative hypothesis (say mu>0). This test arises frequently in particle physics (including dark matter searches), where mu is the signal strength. The frequentist testing approach maps identically onto the frequentist theory of confidence intervals. Thus, as...

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  32. Alessandra Brazzale
    02/08/2019, 15:40
    Talk

    Statisticians summary

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  33. Hugh Lippincott (Fermilab)
    02/08/2019, 16:10
    Talk

    Physicists Summary

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