scholarly journals Search for Neutrino-Induced Neutral Current Delta Radiative Decay in MicroBooNE and a First Test of the MiniBooNE Low Energy Excess Under a Single Photon Hypothesis (submitted to PRL)

2021 ◽  
Author(s):  
Sowjanya Gollapinni ◽  
Robert Fine ◽  
MicroBooNE et al.
Keyword(s):  
Radiative Decay ◽  
Single Photon ◽  
Neutral Current ◽  
Low Energy ◽  
Energy Excess

scholarly journals The MicroBooNE Single-Photon Low-Energy Excess Search

2020 ◽  
Author(s):  
Sowjanya Gollapinni ◽  
Georgia Karagiorgi ◽  
Mark Lonegran ◽  
William Louis ◽  
Richard Van De Water ◽  
...  
Keyword(s):  
Single Photon ◽  
Low Energy ◽  
Energy Excess

scholarly journals Erratum to: A new analysis of the MiniBooNE low-energy excess

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
C. Giunti ◽  
A. Ioannisian ◽  
G. Ranucci
Keyword(s):  
Low Energy ◽  
Correct Version ◽  
Energy Excess

After publication we discovered that some entries in table 2 and the corresponding contours in figures 3 and 4 have been misprinted. We provide here the correct version of table 2 and figures 3 and 4. The discussion and conclusions in the text of the paper remain unchanged.

scholarly journals Spurious poles in the scattering of electric and magnetic charges

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
John Terning ◽  
Christopher B. Verhaaren
Keyword(s):  
Perturbation Theory ◽  
Scattering Amplitudes ◽  
Pair Production ◽  
Magnetic Particles ◽  
Single Photon ◽  
Low Energy ◽  
Magnetic Interactions ◽  
Parity Conservation ◽  
Non Local ◽  
The Way

Abstract Theories with both electric and magnetic charges (“mutually non-local” theories) have several major obstacles to calculating scattering amplitudes. Even when the interaction arises through the kinetic mixing of two, otherwise independent, U(1)’s, so that all low-energy interactions are perturbative, difficulties remain: using a self-dual, local formalism leads to spurious poles at any finite order in perturbation theory. Correct calculations must show how the spurious poles cancel in observable scattering amplitudes. Consistency requires that one type of charge is confined as a result of one of the U(1)’s being broken. Here we show how the constraints of confinement and parity conservation on observable processes manages to cancel the spurious poles in scattering and pair production amplitudes, paving the way for systematic studies of the experimental signatures of “dark” electric-magnetic processes. Along the way we demonstrate some novel effects in electric-magnetic interactions, including that the amplitude for single photon production of magnetic particles by electric particles vanishes.

scholarly journals Studying the low-energy excess in cosmic-ray iron: a possible evidence of a massive supernova activity in the solar neighborhood via primary 60Fe

2021 ◽  
Author(s):  
Nicolo Masi ◽  
M. J. Boschini ◽  
S. Della Torre ◽  
M. Gervasi ◽  
D. Grandi ◽  
...  
Keyword(s):  
Cosmic Ray ◽  
Solar Neighborhood ◽  
Low Energy ◽  
Energy Excess

Single Particle Spectroscopy of Radiative Processes in Colloid-to-Film-Coupled Nanoantennas

2018 ◽  
Vol 232 (9-11) ◽  
pp. 1593-1606 ◽  
Author(s):  
Max J. Schnepf ◽  
Yannic Brasse ◽  
Fabian R. Goßler ◽  
Anja Maria Steiner ◽  
Julian Obermeier ◽  
...  
Keyword(s):  
Single Particle ◽  
Radiative Decay ◽  
Single Photon ◽  
Photon Counting ◽  
Life Time ◽  
Fluorescence Decay ◽  
Decay Rates ◽  
Single Photon Counting ◽  
Radiative Processes ◽  
Particle Level

Abstract We present a fluorescent emitter (rhodamine B) coupled to a dielectric or metallic interface as well as a metallic cavity to study their radiative decay processes. Supported by finite-difference time-domain (FDTD) simulations, we correlate the non-radiative and radiative decay rates with the absorption and scattering cross section efficiencies, respectively. On a single particle level, we use atomic force microscopy (AFM), scanning electron microscopy (SEM), scattering spectroscopy, fluorescence life time imaging (FLIM) and time-correlated single photon counting (TCSPC) to evaluate the enhanced fluorescence decay at the same location. With this study, we show a colloidal gain material, which can be integrated into lattices using existing directed self-assembled methods to study their coherent energy transfer.

scholarly journals Photophysical Properties of Spirobifluorene-Based o-Carboranyl Compounds Altered by Structurally Rotating the Carborane Cages

Molecules ◽  
2019 ◽  
Vol 24 (22) ◽  
pp. 4135
Author(s):  
Seonah Kim ◽  
Hyunhee So ◽  
Ji Hye Lee ◽  
Hyonseok Hwang ◽  
Hyoshik Kwon ◽  
...  
Keyword(s):  
Radiative Decay ◽  
Photophysical Properties ◽  
High Energy ◽  
Low Energy ◽  
Radiative Decays ◽  
Absorption Bands ◽  
Molecular Features ◽  
Td Dft ◽  
Structural Fluctuations ◽  
Energy Emissions

9,9′-Spirobifluorene-based o-carboranyl compounds C1 and C2 were prepared and fully characterized by multinuclear nuclear magnetic resonance (NMR) spectroscopy and elemental analysis. The solid-state structure of C1 was also determined by single-crystal X-ray diffractometry. The two carboranyl compounds display major absorption bands that are assigned to π−π* transitions involving their spirobifluorene groups, as well as weak intramolecular charge-transfer (ICT) transitions between the o-carboranes and their spirobifluorene groups. While C1 only exhibited high-energy emissions (λem = ca. 350 nm) in THF at 298 K due to locally excited (LE) states assignable to π−π* transitions involving the spirobifluorene group alone, a remarkable emission in the low-energy region was observed in the rigid state, such as in THF at 77 K or the film state. Furthermore, C2 displays intense dual emissive patterns in both high- and low-energy regions in all states. Electronic transitions that were calculated by time-dependent-DFT (TD-DFT) for each compound based on ground (S0) and first-excited (S1) state optimized structures clearly verify that the low-energy emissions are due to ICT-based radiative decays. Calculated energy barriers that are based on the relative energies associated with changes in the dihedral angle around the o-carborane cages in C1 and C2 clearly reveal that the o-carborane cage in C1 rotates more freely than that in C2. All of the molecular features indicate that ICT-based radiative decay is only available to the rigid state in the absence of structural fluctuations, in particular the free-rotation of the o-carborane cage.

scholarly journals Constraints on the charged currents in general neutrino interactions with sterile neutrinos

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Tong Li ◽  
Xiao-Dong Ma ◽  
Michael A. Schmidt
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Neutral Current ◽  
New Physics ◽  
Effective Field ◽  
Lepton Number ◽  
Low Energy ◽  
Electroweak Scale ◽  
Sterile Neutrinos ◽  
Neutrino Interactions

Abstract In this work we investigate the implication of low-energy precision measurements on the quark-lepton charged currents in general neutrino interactions with sterile neutrinos in effective field theories. The physics in low-energy measurements is described by the low-energy effective field theory extended with sterile neutrinos (LNEFT) defined below the electroweak scale. We also take into account renormalization group running and match the LNEFT onto the Standard Model (SM) effective field theory with sterile neutrinos (SMNEFT) to constrain new physics (NP) above the electroweak scale. The most sensitive low-energy probes are from leptonic decays of pseudoscalar mesons and hadronic tau lepton decays in terms of precise decay branching fractions, the lepton flavor universality and the Cabibbo-Kobayashi-Maskawa (CKM) unitarity. We also consider other constraints including nuclear beta decay. The constraints on charged current operators are generally stronger than the ones for quark-neutrino neutral current operators. We find that the most stringent bounds on the NP scale of lepton-number-conserving and lepton- number-violating operators in SMNEFT are 74 (110) TeV and 9.8 (13) TeV, respectively, for the operators with down (strange) quark.

scholarly journals The EIGER detector for low-energy electron microscopy and photoemission electron microscopy

2017 ◽  
Vol 24 (5) ◽  
pp. 963-974 ◽  
Author(s):  
G. Tinti ◽  
H. Marchetto ◽  
C. A. F. Vaz ◽  
A. Kleibert ◽  
M. Andrä ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Dynamic Range ◽  
Single Photon ◽  
Low Energy ◽  
Energy Electron ◽  
Frame Rate ◽  
Pixel Detector ◽  
Photoemission Electron Microscopy ◽  
Low Energy Electron ◽  
Photoemission Electron

EIGER is a single-photon-counting hybrid pixel detector developed at the Paul Scherrer Institut, Switzerland. It is designed for applications at synchrotron light sources with photon energies above 5 keV. Features of EIGER include a small pixel size (75 µm × 75 µm), a high frame rate (up to 23 kHz), a small dead-time between frames (down to 3 µs) and a dynamic range up to 32-bit. In this article, the use of EIGER as a detector for electrons in low-energy electron microscopy (LEEM) and photoemission electron microscopy (PEEM) is reported. It is demonstrated that, with only a minimal modification to the sensitive part of the detector, EIGER is able to detect electrons emitted or reflected by the sample and accelerated to 8–20 keV. The imaging capabilities are shown to be superior to the standard microchannel plate detector for these types of applications. This is due to the much higher signal-to-noise ratio, better homogeneity and improved dynamic range. In addition, the operation of the EIGER detector is not affected by radiation damage from electrons in the present energy range and guarantees more stable performance over time. To benchmark the detector capabilities, LEEM experiments are performed on selected surfaces and the magnetic and electronic properties of individual iron nanoparticles with sizes ranging from 8 to 22 nm are detected using the PEEM endstation at the Surface/Interface Microscopy (SIM) beamline of the Swiss Light Source.

scholarly journals Rb, Rc and New Physics: An Updated Model Independent Analysis

1997 ◽  
Vol 12 (04) ◽  
pp. 723-742 ◽  
Author(s):  
P. Bamert
Keyword(s):  
Standard Model ◽  
Neutral Current ◽  
New Physics ◽  
Low Energy ◽  
Coupling Constant ◽  
A Value ◽  
Independent Analysis ◽  
The Standard Model ◽  
Necessary And Sufficient ◽  
Do So

We analyze LEP and SLC data from the 1995 Summer Conferences as well as from low energy neutral current experiments for signals of new physics. The reasons for doing this are twofold: first to explain the deviations from the Standard Model observed in Rb and Rc and second to constrain nonstandard contributions to couplings of the Z0 boson to all fermions and to the oblique parameters. We do so by comparing the data with the Standard Model as well as with a number of test hypotheses concerning the nature of the new physics. These include nonstandard [Formula: see text]-, [Formula: see text]- and [Formula: see text]-couplings as well as the couplings of the Z0 to fermions of the entire first, second and third generations and universal corrections to all up- and down-type quark couplings (as can arise see for example in Z' mixing models). We find that nonstandard [Formula: see text] couplings are both necessary and sufficient to explain the data and in particular the Rb anomaly. It is not possible to explain Rb, Rc and a value of the strong coupling constant consistent with low energy determinations invoking only nonstandard [Formula: see text]- and [Formula: see text]-couplings. To do so one has to have also new physics contributions to the [Formula: see text] or universal corrections to all [Formula: see text] couplings.

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