11,860 research outputs found
Probing neutrino transition magnetic moments with coherent elastic neutrino-nucleus scattering
We explore the potential of current and next generation of coherent elastic
neutrino-nucleus scattering (CENS) experiments in probing neutrino
electromagnetic interactions. On the basis of a thorough statistical analysis,
we determine the sensitivities on each component of the Majorana neutrino
transition magnetic moment (TMM), , that
follow from low-energy neutrino-nucleus experiments. We derive the sensitivity
to neutrino TMM from the first CENS measurement by the COHERENT
experiment, at the Spallation Neutron Source. We also present results for the
next phases of COHERENT using HPGe, LAr and NaI[Tl] detectors and for reactor
neutrino experiments such as CONUS, CONNIE, MINER, TEXONO and RED100. The role
of the CP violating phases in each case is also briefly discussed. We conclude
that future CENS experiments with low-threshold capabilities can improve
current TMM limits obtained from Borexino data.Comment: 25 pages, 8 figures, 2 tables, analysis updated; conclusions
unchanged; references added; matches published versio
Conductor-backed coplanar waveguide resonators of Y-Ba-Cu-O and Tl-Ba-Ca-Cu-O on LaAlO3
Conductor-backed coplanar waveguide (CBCPW) resonators operating at 10.8 GHz have been fabricated from Tl-Ba-Ca-O (TBCCO) and Y-Ba-Cu-O (YBCO) thin films on LaAlO3. The resonators consist of a coplanar waveguide (CPW) patterned on the superconducting film side of the LaAlO3 substrate with a gold ground plane coated on the opposite side. These resonators were tested in the temperature range from 14 to 106 K. At 77 K, the best of our TBCCO and YBCO resonators have an unloaded quality factor (Qo) 7 and 4 times, respectively, larger than that of a similar all-gold resonator. In this study, the Qo's of the TBCCO resonators were larger than those of their YBCO counterparts throughout the aforementioned temperature range
Implications of the first detection of coherent elastic neutrino-nucleus scattering (CEvNS) with Liquid Argon
The CENNS-10 experiment of the COHERENT collaboration has recently reported
the first detection of coherent-elastic neutrino-nucleus scattering (CEvNS) in
liquid Argon with more than significance. In this work, we exploit
the new data in order to probe various interesting parameters which are of key
importance to CEvNS within and beyond the Standard Model. A dedicated
statistical analysis of these data shows that the current constraints are
significantly improved in most cases. We derive a first measurement of the
neutron rms charge radius of Argon, and also an improved determination of the
weak mixing angle in the low energy regime. We also update the constraints on
neutrino non-standard interactions, electromagnetic properties and light
mediators with respect to those derived from the first COHERENT-CsI data.Comment: discussion expanded including light mediators and nuclear
uncertainties, figures added, references added. V3: Fig. 7 corrected,
conclusions unchange
Millimeter wave surface resistance of RBa2Cu3O(7-delta) (R=Y,Eu,Dy,Sm,Er) superconductors
The measurements are reported of the millimeter wave surface resistance R(sub s) at 58.6 GHz of bulk samples of RBa2Cu3O(7-delta) (R = Y,Eu,Dy,Sm,Er) and of YBa2Cu3O(7-delta) superconducting films, in the temperature range from 20 to 300 K. The bulk samples were prepared by cold pressing the powders of RBa2Cu3O(7-delta) into one in. disks. The powders were prepared by several sinterings in one atmosphere of oxygen at 925 C, with grindings between sinterings, to obtain the superconducting phase. The thin films were deposited on SrTiO3 and LaGaO3 substrates by pulsed laser ablation. Each sample was measured by replacing the end wall of a gold-plated Te sub 013 circular mode copper cavity with the sample and determining the cavity quality factor . From the difference in the Q-factor of the cavity, with and without the sample, the R(sub s) of the sample was determined
Determination of surface resistance and magnetic penetration depth of superconducting YBa2Cu3O(7-delta) thin films by microwave power transmission measurements
A novel waveguide power transmission measurement technique was developed to extract the complex conductivity of superconducting thin films at microwave frequencies. The microwave conductivity was taken of two laser ablated YBa2Cu3O(7-delta) thin films on LaAlO3 with transition temperatures of approx. 86.3 and 82 K, respectively, in the temperature range 25 to 300 K. From the conductivity values, the penetration depth was found to be approx. 0.54 and 0.43 micron, and the surface resistance (R sub s) to be approx. 24 and 36 micro-Ohms at 36 GHz and 76 K for the two films under consideration. The R sub s values were compared with those obtained from the change in the Q-factor of a 36 GHz Te sub 011-mode (OFHC) copper cavity by replacing one of its end walls with the superconducting sample. This technique allows noninvasive characterization of high transition temperature superconducting thin films at microwave frequencies
Arrival directions of large air showers, low-mu showers and old-age low-mu air showers observed at St. Chacaltaya
Arrival directions of air showers with primary energies in the range 10 to the 16.5 power eV to 10 to the 18th power eV show the first harmonic in right ascension (RA) with amplitude of 2.7 + or - 1.0% and phase of 13-16h. However, the second harmonic in RA slightly seen for showers in the range 10 to the 18th power eV to 10 to the 19th power eV disappeared by accumulation of observed showers. The distribution of arrival directions of low-mu air showers with primary energies around 10 to the 15th power eV observed at Chacaltaya from 1962 to 1967 is referred to, relating to the above-mentioned first harmonic. Also presented in this paper are arrival directions of old-age low-mu air showers observed at Chacaltaya from 1962 to 1967, for recent interest in gamma-ray air showers
Energetic delayed hadrons in large air showers observed at 5200m above sea level
Energetic delayed hadrons in air showers with electron sizes in the range 10 to the 6th power to 10 to the 9th power were studied by observing the delayed bursts produced in the shield of nine square meter scintillation detectors in the Chacaltaya air-shower array. The frequency of such delayed burst is presented as a function of electron size, core distance and sec theta
Effects of initial flow conditions on primary breakup of nonturbulent and turbulent liquid jets
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77013/1/AIAA-1994-561-646.pd
Experimental Study on the Detection of Frozen Diffused Ammonia Blockage in the Inactive Section of a Variable Conductance Heat Pipe
Variable Conductance Heat Pipes (VCHP) are mainly employed to cool down
electronic systems in spacecraft applications, as they can handle high
temperature fluctuations in their cold source, preventing thus the systems from
damaging. These fluctuations, as well as ultra-low temperatures, are always
present in outer space, and one of the key steps in a VCHP design is therefore
to make sure that they endure these conditions. However, not much has been
written about their resilience during and after a long exposition to
subfreezing conditions, i.e. temperatures lower than the freezing point of the
working fluid. In this paper we implement and validate a computational routine
based on a modified Flat-Front Approach to predict the VCHP temperature profile
and to determine the location of the gas-vapor front. Then we continuously
expose an ammonia/stainless-steel VCHP to temperatures below the ammonia
freezing point for 211 hours, to later examine the formation and subsequent
dynamics of a thin block of frozen ammonia which is diffused into the inactive
part of the heat pipe condenser. We describe as well how a strong correlation
between the adiabatic section and the reservoir temperatures is maintained (or
broken) upon the occurrence (or absence) of the blockage of frozen ammonia.Comment: Under review for possible publication in Applied Thermal Engineerin
Millimeter wave transmission studies of YBa2Cu3O7-delta thin films in the 26.5 to 40.0 GHz frequency range
Millimeter wave transmission measurements through YBa2Cu3O(7-delta) thin films on MgO, ZrO2 and LaAlO3 substrates, are reported. The films (approx. 1 micron) were deposited by sequential evaporation and laser ablation techniques. Transition temperatures T sub c, ranging from 89.7 K for the Laser Ablated film on LaAlO3 to approximately 72 K for the sequentially evaporated film on MgO, were obtained. The values of the real and imaginary parts of the complex conductivity, sigma 1 and sigma 2, are obtained from the transmission data, assuming a two fluid model. The BCS approach is used to calculate values for an effective energy gap from the obtained values of sigma sub 1. A range of gap values from 2 DELTA o/K sub B T sub c = 4.19 to 4.35 was obtained. The magnetic penetration depth is evaluated from the deduced values of sigma 2. These results are discussed together with the frequency dependence of the normalized transmission amplitude, P/P sub c, below and above T sub c
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