Search for dark photons using a multilayer dielectric haloscope equipped with a single-photon avalanche diode

We report on the results of the search for dark photons with mass around 1.5$\,\rm eV/c^2$ using a multilayer dielectric haloscope equipped with an affordable and commercially available photosensor. The multilayer stack, which enables the conversion of dark photons (DP) to Standard Model photons, is made of 23 bilayers of alternating SiO$_2$ and Si$_3$N$_4$ thin films with linearly increasing thicknesses through the stack (a configuration known as a "chirped stack"). The thicknesses have been chosen according to an optimisation algorithm in order to maximise the DP-photon conversion in the energy region where the photosensor sensitivity peaks. This prototype experiment, baptised MuDHI (Multilayer Dielectric Haloscope Investigation) by the authors of this paper, has been designed, developed and run at the Astroparticle Laboratory of New York University Abu Dhabi, which marks the first time a dark matter experiment has been operated in the Middle East. No significant signal excess is observed, and the method of maximum log-likelihood is used to set exclusion limits at $90\%$ confidence level on the kinetic mixing coupling constant between dark photons and ordinary photons

Study of dark counts in optical superconducting transition-edge sensors

Superconducting transition-edge sensors (TESs), known for their high single-photon detection efficiency and low background, are increasingly being used in rare event searches. We present the first comprehensive characterization of optical TES backgrounds, identifying three event types: high-energy, electrical noise, and photon-like events. We experimentally verify and simulate the source of the high-energy events. We develop an algorithm to isolate photon-like events, the expected signal in dark matter searches, achieving record-low photon-like dark count rates in the 0.8-3.2 eV energy range

Statistical Modelling and Inference for XENON1T

A great number of astrophysical observations suggests that of the matter in our universe, only a sixth is made up of known matter. The rest, named dark matter, has not been successfully identified. This thesis presents the analysis and statistical inference that was used by the XENON1T collaboration to conduct a search for a particular dark matter candidate; weakly interacting massive particles (WIMPs).   XENON1T is a dual-phase time projection chamber that can detect particles scattering in a 2 tonne target of liquid xenon with deposited recoil energies above ~3 keV. This is low enough to observe the elastic recoil between a WIMP and a xenon nucleus for WIMP masses &gt;5 GeV c-2. The results presented in this thesis use 278.8 days of data, with an analysis mass of 1.3 tonne.   XENON1T uses models for backgrounds and signals within this volume to construct a combined likelihood for two science data-taking periods as well as calibration data-sets. Fits to simulated data-sets were used to calibrate and validate the confidence interval construction. In addition, analysis choices were evaluated both to optimize the discovery power and expected sensitivity of the search, and to improve the robustness of the analysis.   No significant excess was observed in the search for a spin-independent WIMP-nucleon interaction for any WIMP masses between 6  GeV c-2 and 104 GeV c-2 for the 1 ton-year exposure. This analysis produced the strongest constraint on the spin-independent WIMP-nucleon cross-section so far, with a minimum of 4.1 10-47 cm2  for a 30 GeV c-2 WIMP.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript. Paper 5: Manuscript.</p

Dark Matter Searches with ATLAS and Fermi

This thesis presents Dark matter inspired searches for supersymmetry with a one-tau analysis at ATLAS, which excludes a region close to that of allowed dark matter densities at m_0 ~ 400 GeV, m_1/2 ~ 600 GeV, tan \beta = 30, A_0 = -1200 GeV in a "Higgs aware grid". The one tau analysis was among the first groups to constrain regions of this grid at ATLAS. In addition, this thesis presents a computation of variables and limits in the mSUGRAparameter space, both by astrophysical experiments and other observables. The new Higgs mass and the LHCb measurement of BR(B_s \rightarrow \mu^+ \mu^- ) impose constraints on large areas of the parameter space. However, some regions of interest are still there; the Higgs-aware grid was a good example. Also, in the region tan \beta = 30, A_0 = - 2300 GeV some promise may be found for both astro- and high-energy physics. Last; This thesis presents an exploration of the Fermi-LAT photon data in support of an ongoing effort to investigate the planned CTAs potential. Last spring, a paper present- ing a line feature at 130 GeV [70] in the Fermi-LAT spectrum was published, which has engendered an appropriately cautious response; both in view of the lack, for now, of a second experiment, as well as the importance a discovery would have

JelleAalbers/blueice: v1.2.0

&lt;ul&gt; &lt;li&gt;Prevent negative rates being passed to Barlow-Beeston equation, and allow per-event weights (#32)&lt;/li&gt; &lt;li&gt;Add likelihood that takes coupling as shape parameters (#34)&lt;/li&gt; &lt;li&gt;Patch for tests (#37)&lt;/li&gt; &lt;li&gt;Use scipy stats for PoissonLL (#40)&lt;/li&gt; &lt;li&gt;Do not scale mus when livetime_days is 0 (#41)&lt;/li&gt; &lt;/ul&gt

Publishing statistical models: Getting the most out of particle physics experiments

International audienceThe statistical models used to derive the results of experimental analyses are of incredible scientific value and are essential information for analysis preservation and reuse. In this paper, we make the scientific case for systematically publishing the full statistical models and discuss the technical developments that make this practical. By means of a variety of physics cases -- including parton distribution functions, Higgs boson measurements, effective field theory interpretations, direct searches for new physics, heavy flavor physics, direct dark matter detection, world averages, and beyond the Standard Model global fits -- we illustrate how detailed information on the statistical modelling can enhance the short- and long-term impact of experimental results