Displaced Signal Research Articles

Sub-shot-noise-limited fiber-optic quantum receiver

We experimentally demonstrate a quantum receiver based on Kennedy scheme for discrimination between two phase-modulated weak coherent states. The receiver is assembled entirely from the standard fiber-optic elements and operates at the conventional telecom wavelength 1.55 microns. The local oscillator and the signal are transmitted through different optical fibers, and the displaced signal is measured with a high-efficiency superconducting nanowire single-photon detector. We show the discrimination error rate two times below the shot-noise limit.

Sampling the mu nu SSM for displaced decays of the tau left sneutrino LSP at the LHC

Within the framework of the mu nu mathrm{SSM}, a displaced dilepton signal is expected at the LHC from the decay of a tau left sneutrino as the lightest supersymmetric particle (LSP) with a mass in the range 45–100 GeV. We compare the predictions of this scenario with the ATLAS search for long-lived particles using displaced lepton pairs in pp collisions, considering an optimization of the trigger requirements by means of a high level trigger that exploits tracker information. The analysis is carried out in the general case of three families of right-handed neutrino superfields, where all the neutrinos get contributions to their masses at tree level. To analyze the parameter space, we sample the mu nu SSM for a tau left sneutrino LSP with proper decay length ctau > 0.1 , hbox {mm} using a likelihood data-driven method, and paying special attention to reproduce the current experimental data on neutrino and Higgs physics, as well as flavor observables. The sneutrino is special in the mu nu mathrm{SSM} since its couplings have to be chosen so that the neutrino oscillation data are reproduced. We find that important regions of the parameter space can be probed at the LHC run 3.

Looking for the left sneutrino LSP with displaced-vertex searches

We analyze a displaced dilepton signal expected at the LHC for a tau left sneutrino as the lightest supersymmetric particle with a mass in the range $45$-$100$ GeV. The sneutrinos are pair produced via a virtual $W$, $Z$ or $\gamma$ in the $s$ channel and, given the large value of the tau Yukawa coupling, their decays into two dileptons or a dilepton plus missing transverse energy from neutrinos can be significant. The discussion is carried out in the $\mu \nu$SSM, where the presence of $R$-parity violating couplings involving right-handed neutrinos solves the $\mu$ problem and can reproduce the neutrino data. To probe the tau left sneutrinos we compare the predictions of the $\mu \nu$SSM with the ATLAS search for long-lived particles using displaced lepton pairs in $pp$ collisions at $\sqrt s= 8$ TeV, allowing us to constrain the parameter space of the model. We also consider an optimization of the trigger requirements used in existing displaced-vertex searches by means of a High Level Trigger that exploits tracker information. This optimization is generically useful for a light metastable particle decaying into soft charged leptons. The constraints on the sneutrino turn out to be more stringent. We finally discuss the prospects for the $13$ TeV LHC searches as well as further potential optimizations.

Displaced vertex searches for sterile neutrinos at future lepton colliders

We investigate the sensitivity of future lepton colliders to displaced vertices from the decays of long-lived heavy (almost sterile) neutrinos with electroweak scale masses and detectable time of flight. As future lepton colliders we consider the FCC-ee, the CEPC, and the ILC, searching at the Z-pole and at the center-of-mass energies of 240, 350 and 500 GeV. For a realistic discussion of the detector response to the displaced vertex signal and the Standard Model background we consider the ILC's Silicon Detector (SiD) as benchmark for the future lepton collider detectors. We find that displaced vertices constitute a powerful search channel for sterile neutrinos, sensitive to squared active-sterile mixing angles as small as $10^{-11}$.

The dark penguin shines light at colliders

Collider experiments are one of the most promising ways to constrain Dark Matter (DM) interactions. For several types of DM-Standard Model couplings, a meaningful interpretation of the results requires to go beyond effective field theory, considering simplified models with light mediators. This is especially important in the case of loop-mediated interactions. In this paper we perform the first simplified model study of the magnetic dipole interacting DM, by including the one-loop momentum-dependent form factors that mediate the coupling — given by the Dark Penguin — in collider processes. We compute bounds from the monojet, monophoton, and diphoton searches at the 8 and 14 TeV LHC, and compare the results to those of direct and indirect detection experiments. Future searches at the 100 TeV hadron collider and at the ILC are also addressed. We find that the optimal search strategy requires loose cuts on the missing transverse energy, to capture the enhancement of the form factors near the threshold for on-shell production of the mediators. We consider both minimal models and models where an additional state beyond the DM is accessible. In the latter case, under the assumption of anarchic flavor structure in the dark sector, the LHC monophoton and diphoton searches will be able to set much stronger bounds than in the minimal scenario. A determination of the mass of the heavier dark fermion might be feasible using the MT2 variable. In addition, if the Dark Penguin flavor structure is almost aligned with that of the DM mass, a displaced signal from the decay of the heavier dark fermion into the DM and photon can be observed. This allows us to set constraints on the mixings and couplings of the model from an existing search for non-pointing photons.

Homogeneous Cell-Based Fluorescence Polarization Assay for the Direct Detection of cAMP

A fluorescence polarization-based functional assay for cyclic AMP (cAMP) production in cells has been proven effective for the detection of agonist-stimulated cAMP production in a HEK 293 recombinant cell line expressing the corticotropin-releasing factor subtype 2alpha (CRF2alpha) receptor. Assays were completed in a single well of a 384-well microplate with no transfer, separation, or wash steps incurred. The assay performance is excellent for adaptation to the high throughput screening environment in terms of speed of analysis, magnitude of displaced signal, precision, and detection limits for cAMP quantitation. Relative potencies of agonists and antagonists are maintained with respect to radiometric assays. The assay withstands up to 5% DMSO and up to 10 microM concentrations of highly colored compound. These attributes suggest that accurate assessment of drug binding can be measured using this assay.

New Products

A fluorescence polarization-based functional assay for cyclic AMP (cAMP) production in cells has been proven effective for the detection of agonist-stimulated cAMP production in a HEK 293 recombinant cell line expressing the corticotropin-releasing factor subtype 2cr (CRF2a) receptor. Assays were completed in a single well of a 384-well microplate with no transfer, separation, or wash steps incurred. The assay performance is excellent for adaptation to the high throughput screening environment in terms of speed of analysis, magnitude of displaced signal, precision, and detection limits for cAMP quantitation. Relative potencies of agonists and antagonists are maintained with respect to radiometric assays. The assay withstands up to 5% DMSO and up to 10 μM concentrations of highly colored compound. These attributes suggest that accurate assessment of drug binding can be measured using this assay.

Diabetes insipidus.

Diabetes insipidus.

STATE MEASUREMENT BY PHOTON FILTERING IN A RING CAVITY

We suggest a method for measuring the photon number distribution and the density matrix of a single-mode radiation field. The setup consists of a chain of active ring cavities, each fed by a strong coherent probe and coupled to the signal through cross-Kerr phase modulation. Each cavity is set at resonance by a different Fock component of the signal, so that the detection probability at the cavities output is proportional to the signal photon statistics. The off-diagonal elements of the density matrix can be evaluated by measuring the photon statistics of a set of displaced signal states. The suggested setup allows a reliable state measurement even with low quantum efficiency at detectors.

The effect of delaying auditory feedback of selected components of the speech signal.

Can the disturbance that occurs in delayed auditory feedback tasks be explained by problems caused by the amplitude contour of the displaced signal, or is information about the position of the articulators used for feedback control? To test these alternative hypotheses of the effects of delayed auditory feedback, the effects of varying the amplitude contour of the delayed signal were assessed when phonetic information in the delayed signal was degraded. Two experiments are reported in which the speech signal is split into two bands and each band is delayed by different times. The amplitude of one or both of these bands was varied in Experiment 2. Performance was not as disrupted when only one band was delayed as when both were. In Experiment 2, it was found that increasing the amplitude of the band that was not delayed did not disrupt performance, whereas increasing the amplitude of the delayed band did disrupt performance, particularly at a delay of 200 msec. The results are interpreted as showing that the amplitude contour of the displaced signal causes control problems with speech in delayed auditory feedback tasks.