We report on the results from a search for dark matter axions with the HAYSTAC experiment using a microwave cavity detector at frequencies between 5.6 and 5.8 GHz. We exclude axion models with two ...photon coupling gaγγ≳2×10−14 GeV−1, a factor of 2.7 above the benchmark KSVZ model over the mass range 23.15<ma<24.0 μeV. This doubles the range reported in our previous paper. We achieve a near-quantum-limited sensitivity by operating at a temperature T<hν/2kB and incorporating a Josephson parametric amplifier (JPA), with improvements in the cooling of the cavity further reducing the experiment’s system noise temperature to only twice the standard quantum limit at its operational frequency, an order of magnitude better than any other dark matter microwave cavity experiment to date. This result concludes the first phase of the HAYSTAC program utilizing a conventional copper cavity and a single JPA.
We present new constraints on the dark matter-induced annual modulation signal using 1.7 years of COSINE-100 data with a total exposure of 97.7 kg yr. The COSINE-100 experiment, consisting of 106 kg ...of NaI(Tl) target material, is designed to carry out a model-independent test of DAMA/LIBRA's claim of WIMP discovery by searching for the same annual modulation signal using the same NaI(Tl) target. The crystal data show a 2.7 cpd/kg/keV background rate on average in the 2-6 keV energy region of interest. Using a χ-squared minimization method we observe best fit values for modulation amplitude and phase of 0.0092±0.0067 cpd/kg/keV and 127.2±45.9 d, respectively.
In experiments searching for axionic dark matter, the use of the standard threshold-based data analysis discards valuable information. We present a Bayesian analysis framework that builds on an ...existing processing protocol B. M. Brubaker, L. Zhong, S. K. Lamoreaux, K. W. Lehnert, and K. A. van Bibber, Phys. Rev. D 96, 123008 (2017) to extract more information from the data of coherent axion detectors such as operating haloscopes. The analysis avoids logical subtleties that accompany the standard analysis framework and enables greater experimental flexibility on future data runs. Performing this analysis on the existing data from the HAYSTAC experiment, we find improved constraints on the axion-photon coupling gγ while also identifying the most promising regions of parameter space within the 23.15 – 24.0 μ eV mass range. A comparison with the standard threshold analysis suggests a 36% improvement in scan rate from our analysis, demonstrating the utility of this framework for future axion haloscope analyses.
Initial performance of the COSINE-100 experiment Adhikari, G.; Adhikari, P.; de Souza, E. Barbosa ...
The European physical journal. C, Particles and fields,
02/2018, Letnik:
78, Številka:
2
Journal Article
Recenzirano
Odprti dostop
COSINE is a dark matter search experiment based on an array of low background NaI(Tl) crystals located at the Yangyang underground laboratory. The assembly of COSINE-100 was completed in the summer ...of 2016 and the detector is currently collecting physics quality data aimed at reproducing the DAMA/LIBRA experiment that reported an annual modulation signal. Stable operation has been achieved and will continue for at least 2 years. Here, we describe the design of COSINE-100, including the shielding arrangement, the configuration of the NaI(Tl) crystal detection elements, the veto systems, and the associated operational systems, and we show the current performance of the experiment.
The manipulation of quantum states of light
holds the potential to enhance searches for fundamental physics. Only recently has the maturation of quantum squeezing technology coincided with the ...emergence of fundamental physics searches that are limited by quantum uncertainty
. In particular, the quantum chromodynamics axion provides a possible solution to two of the greatest outstanding problems in fundamental physics: the strong-CP (charge-parity) problem of quantum chromodynamics
and the unknown nature of dark matter
. In dark matter axion searches, quantum uncertainty manifests as a fundamental noise source, limiting the measurement of the quadrature observables used for detection. Few dark matter searches have approached this limit
, and until now none has exceeded it. Here we use vacuum squeezing to circumvent the quantum limit in a search for dark matter. By preparing a microwave-frequency electromagnetic field in a squeezed state and near-noiselessly reading out only the squeezed quadrature
, we double the search rate for axions over a mass range favoured by some recent theoretical projections
. We find no evidence of dark matter within the axion rest energy windows of 16.96-17.12 and 17.14-17.28 microelectronvolts. Breaking through the quantum limit invites an era of fundamental physics searches in which noise reduction techniques yield unbounded benefit compared with the diminishing returns of approaching the quantum limit.
We present a background model for dark matter searches using an array of NaI(Tl) crystals in the COSINE-100 experiment that is located in the Yangyang underground laboratory. The model includes ...background contributions from both internal and external sources, including cosmogenic radionuclides and surface
210
Pb contamination. To build the model in the low energy region, with a threshold of 1 keV, we used a depth profile of
210
Pb contamination in the surface of the NaI(Tl) crystals determined in a comparison between measured and simulated spectra. We also considered the effect of the energy scale errors propagated from the statistical uncertainties and the nonlinear detector response at low energies. The 1.7 years COSINE-100 data taken between October 21, 2016 and July 18, 2018 were used for this analysis. Our Monte Carlo simulation provides a non-Gaussian peak around 50 keV originating from beta decays of bulk
210
Pb in a good agreement with the measured background. This model estimates that the activities of bulk
210
Pb and
3
H are dominating the background rate that amounts to an average level of
2.85
±
0.15
counts/day/keV/kg in the energy region of (1–6) keV, using COSINE-100 data with a total exposure of 97.7 kg
·
years.
Purpose: To evaluate the effectiveness and safety of lurasidone 80 mg/day (versus the 40 mg/day dose) during a 12-week, open-label extension study in patients with an acute exacerbation of ...schizophrenia who had completed a 6-week double-blind study of lurasidone. Patients and Methods: A total of 289 adult patients with schizophrenia completed the double-blind study and enrolled in the 12-week extension study. Lurasidone was flexibly dosed at 40 or 80 mg/day. Effectiveness measures included the Positive and Negative Syndrome Scale (PANSS) subscale scores, Clinical Global Impression-Severity Scale (CGI-S), and Calgary Depression Scale for Schizophrenia (CDSS), analyzed based on last observation carried forward (LOCF-endpoint). Safety/tolerability assessments included adverse events, body weight, laboratory tests, and discontinuation due to adverse events. Results: Mean endpoint change was greater for lurasidone in modal doses of 80 mg/d (N=136) vs 40 mg/d (N=153) on the PANSS positive subscale (-3.0 vs -2.3), PANSS negative subscale (-1.9 vs -1.7), PANSS General Psychopathology subscale (-5.1 vs -3.8), the CGI-S score (-0.5 vs -0.4), and the CDSS score (-0.7 vs -0.1). Discontinuation rates due to adverse events on lurasidone modal 80 mg/d vs 40 mg/d were 4.4% vs 7.2%; and the most common adverse events in the modal 80 mg/d group were nasopharyngitis, 7.4% (vs 4.6% on modal 40 mg/d), constipation, 5.9% (vs 2.0%), and headache, 5.9% (vs 2.0%). Conclusion: In patients with acute schizophrenia treated with lurasidone 40 mg/d, increasing the dose to 80 mg/d was well tolerated, and was associated with greater improvement in PANSS subscale scores compared to continued treatment with a dose of 40 mg/d. Keywords: lurasidone, schizophrenia, extension treatment, dose escalation, effectiveness, safety
We present a comprehensive study of the nonproportionality of NaI(Tl) scintillation detectors within the context of dark matter search experiments. Our investigation, which integrates COSINE-100 data ...with supplementary
γ
spectroscopy, measures light yields across diverse energy levels from full-energy
γ
peaks produced by the decays of various isotopes. These
γ
peaks of interest were produced by decays supported by both long and short-lived isotopes. Analyzing peaks from decays supported only by short-lived isotopes presented a unique challenge due to their limited statistics and overlapping energies, which was overcome by long-term data collection and a time-dependent analysis. A key achievement is the direct measurement of the 0.87 keV light yield, resulting from the cascade following electron capture decay of
22
Na
from internal contamination. This measurement, previously accessible only indirectly, deepens our understanding of NaI(Tl) scintillator behavior in the region of interest for dark matter searches. This study holds substantial implications for background modeling and the interpretation of dark matter signals in NaI(Tl) experiments.
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