Methods for fast and accurate material properties estimate with terahertz time-domain spectroscopy in transmission and reflection with optically thick materials

With the development of terahertz time-domain spectroscopy, methods have been proposed to precisely estimate the thickness, refractive index, and attenuation coefficient of a sample. In this article, we propose a new method to compute these parameters. In this method, the attenuation is expressed in function of the refractive index. The theoretical unwrapped angle, which therefore only depends on the refractive index, is then matched to the experimental value. By applying already existing methods for estimating the thickness of an optically thick sample, the dielectric properties of the sample can be deduced. The method is applied both to the transmission and reflection spectroscopy. A demonstration of the method and a comparison with the previous methods are finally shown

THz Spectroscopy Analysis of Crystallinity Optimization for Enhanced Piezoelectricity in Biodegradable Poly-L-Lactide Acid

Our research delves into both the fabrication and analysis of biodegradable Poly-L-Lactic Acid (PLLA) films. Specifically, we investigate how stretching impacts the piezoelectric properties of PLLA films. By employing advanced techniques such as Terahertz Time-Domain Spectroscopy (THz-TDS), we aim to unveil previously undiscovered aspects of PLLA\u27s behavior under strain. This includes quantifying changes in crystallinity and observing alterations in piezoelectric responses and absorption spectra. Our study not only emphasizes the fabrication of PLLA as a biodegradable material but also explores its piezoelectric performance, involving methods such as inducing strain and measuring the piezoelectric output. Through this multifaceted approach, we strive to contribute to the progression of sustainable biomaterials and the design of innovative biomedical devices

Constraining off-shell production of axionlike particles with Zγ and WW differential cross-section measurements

This article describes a search for low-mass axionlike particles (ALPs) at the Large Hadron Collider (LHC). If ALPs were produced at the LHC via gluon-gluon fusion and decayed to bosons, the energy dependence of the measured diboson cross-sections would differ from the Standard Model expectation. Measurements of WW and Zγ differential cross sections by the ATLAS collaboration are interpreted to constrain ALP couplings to W-, Z-bosons and photons assuming gluon-gluon-fusion production

Constraining off-shell production of axion-like particles with ZγZ\gamma and WWWW differential cross-section measurements

This article describes a search for low-mass axionlike particles (ALPs) at the Large Hadron Collider (LHC). If ALPs were produced at the LHC via gluon-gluon fusion and decayed to bosons, the energy dependence of the measured diboson cross-sections would differ from the Standard Model expectation. Measurements of $WW$ and Z$γ$ differential cross sections by the ATLAS collaboration are interpreted to constrain ALP couplings to $W$-, $Z$-bosons and photons assuming gluon-gluon-fusion production

Observation of WWW Production in pp Collisions at √s = 13 TeV with the ATLAS Detector

This Letter reports the observation of W W W production and a measurement of its cross section using 139     fb − 1 of proton-proton collision data recorded at a center-of-mass energy of 13 TeV by the ATLAS detector at the Large Hadron Collider. Events with two same-sign leptons (electrons or muons) and at least two jets, as well as events with three charged leptons, are selected. A multivariate technique is then used to discriminate between signal and background events. Events from W W W production are observed with a significance of 8.0 standard deviations, where the expectation is 5.4 standard deviations. The inclusive W W W production cross section is measured to be 820 ± 100   ( stat ) ± 80   ( syst )     fb , approximately 2.6 standard deviations from the predicted cross section of 511 ± 18     fb calculated at next-to-leading-order QCD and leading-order electroweak accuracy