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.
The QCD axion is a leading dark matter candidate that emerges as part of the solution to the strong-CP problem in the Standard Model. The coupling of the axion to photons is the most common ...experimental probe, but much parameter space remains unexplored. The coupling of the QCD axion to the Standard Model scales linearly with the axion mass; therefore, the highly motivated region 0.4–120 neV, corresponding to a GUT-scale axion, is particularly difficult to reach. This paper presents the design requirements for a definitive search for GUT-scale axions and reviews the technological advances needed to enable this program.
CUPID-Mo is a bolometric experiment to search for neutrinoless double-beta decay (
0
ν
β
β
) of
100
Mo
. In this article, we detail the CUPID-Mo detector concept, assembly and installation in the ...Modane underground laboratory, providing results from the first datasets. The CUPID-Mo detector consists of an array of 20
100
Mo
-enriched 0.2 kg
Li
2
MoO
4
crystals operated as scintillating bolometers at
∼
20
mK
. The
Li
2
MoO
4
crystals are complemented by 20 thin Ge optical bolometers to reject
α
events by the simultaneous detection of heat and scintillation light. We observe a good detector uniformity and an excellent energy resolution of 5.3 keV (6.5 keV) FWHM at 2615 keV, in calibration (physics) data. Light collection ensures the rejection of
α
particles at a level much higher than 99.9% – with equally high acceptance for
γ
/
β
events – in the region of interest for
100
Mo
0
ν
β
β
. We present limits on the crystals’ radiopurity:
≤
3
μ
Bq/kg
of
226
Ra
and
≤
2
μ
Bq/kg
of
232
Th
. We discuss the science reach of CUPID-Mo, which can set the most stringent half-life limit on the
100
Mo
0
ν
β
β
decay in half-a-year’s livetime. The achieved results show that CUPID-Mo is a successful demonstrator of the technology developed by the LUMINEU project and subsequently selected for the CUPID experiment, a proposed follow-up of CUORE, the currently running first tonne-scale bolometric
0
ν
β
β
experiment.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The CDMS low ionization threshold experiment (CDMSlite) uses cryogenic germanium detectors operated at a relatively high bias voltage to amplify the phonon signal in the search for weakly interacting ...massive particles (WIMPs). Results are presented from the second CDMSlite run with an exposure of 70 kg day, which reached an energy threshold for electron recoils as low as 56 eV. A fiducialization cut reduces backgrounds below those previously reported by CDMSlite. New parameter space for the WIMP-nucleon spin-independent cross section is excluded for WIMP masses between 1.6 and 5.5 GeV/c^{2}.
We present the potential sensitivity of a future recoil detector for a first detection of the process of coherent elastic neutrino nucleus scattering (CE NS). We use the Chooz reactor complex in ...France as our luminous source of reactor neutrinos. Leveraging the ability to cleanly separate the rate correlated with the reactor thermal power against (uncorrelated) backgrounds, we show that a 10 kg cryogenic bolometric array with 100 eV threshold should be able to extract a CE NS signal within one year of running.
Dry Dilution Refrigerators (DDR) based on pulse tube cryo-coolers have started to replace Wet Dilution Refrigerators (WDR) due to the ease and low cost of operation. However these advantages come at ...the cost of increased vibrations, induced by the pulse tube. In this work, we present the vibration measurements performed on three different commercial DDRs. We describe in detail the vibration measurement system we assembled, based on commercial accelerometers, conditioner and DAQ, and examined the effects of the various damping solutions utilized on three different DDRs, both in the low and high frequency regions. Finally, we ran low temperature, pseudo-massive (30 and 250g) germanium bolometers in the best vibration-performing system under study and report on the results.
To compare the relative effectiveness and side effect profiles of antimetabolite drugs in the treatment of noninfectious ocular inflammation.
Retrospective cohort study.
A total of 257 patients with ...inflammatory eye disease seen in a single-center, academic practice and treated with an antimetabolite as a first-line immunosuppressive agent from 1984 to 2006.
Data recorded included demographics, antimetabolite and prednisone doses, use of other immunosuppressive drugs, response to therapy, and side effects associated with drug use.
Ability to control ocular inflammation and to taper prednisone to <or=10 mg daily ("treatment success"); incidence of treatment-related side effects.
Ninety patients with inflammatory eye disease were treated with methotrexate, 38 patients were treated with azathioprine, and 129 patients were treated with mycophenolate. Uveitis accounted for the majority of the diagnoses (67%, 66%, and 68% for methotrexate, azathioprine, and mycophenolate, respectively), followed by scleritis (23%, 18%, 17% for methotrexate, azathioprine, and mycophenolate, respectively). The median time to treatment success was 4.0, 4.8, and 6.5 months for the mycophenolate, azathioprine, and methotrexate treatment groups, respectively (P = 0.02, log-rank test). The incidence of side effects was higher in the azathioprine group (0.29/person-year PY) compared with patients treated with methotrexate (0.14/PY) and mycophenolate (0.18/PY). More patients discontinued the drug because of side effects in the azathioprine group (0.24/PY vs 0.09/PY for the methotrexate group and 0.09/PY for the mycophenolate mofetil group).
These data suggest that the time to control of ocular inflammation is faster with mycophenolate than with methotrexate. Azathioprine therapy has a higher rate of treatment-related side effects compared with the other 2 agents.
Neutrinoless double beta decay (0νββ) processes sample a wide range of intermediate forbidden nuclear transitions, which may be impacted by quenching of the axial vector coupling constant (gA/gV), ...the uncertainty of which plays a pivotal role in determining the sensitivity reach of 0νββ experiments. Here we present measurements performed on a high-resolution LiInSe2 bolometer in a “source = detector” configuration to measure the spectral shape of the fourfold forbidden β decay of 115In . The value of gA/gV is determined by comparing the spectral shape of theoretical predictions to the experimental β spectrum taking into account various simulated background components as well as a variety of detector effects. We find evidence of quenching of gA/gV at >5 σ with a model-dependent quenching factor of 0.655 ± 0.002 as compared to the free-nucleon value for the interacting shell model. We also measured the 115In half-life to be 5.18 ± 0.06(stat) $^{+0.005}_{- 0.015}$(sys) x 1014 yr within the interacting shell model framework. This Letter demonstrates the power of the bolometeric technique to perform precision nuclear physics single-β decay measurements, which along with improved nuclear modeling can help reduce the uncertainties in the calculation of several decay nuclear matrix elements including those used in 0νββ sensitivity calculations.
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