University of Mons

About: University of Mons is a education organization based out in Mons, Belgium. It is known for research contribution in the topics: Large Hadron Collider & Standard Model. The organization has 3073 authors who have published 9465 publications receiving 294776 citations.

On The Uniqueness of Minimal Coupling in Higher-Spin Gauge Theory

Abstract: We address the uniqueness of the minimal couplings between higher-spin fields and gravity. These couplings are cubic vertices built from gauge non-invariant connections that induce non-abelian deformations of the gauge algebra. We show that Fradkin-Vasiliev's cubic 2?s?s vertex, which contains up to 2s?2 derivatives dressed by a cosmological constant ?, has a limit where: (i) ????0; (ii) the spin-2 Weyl tensor scales non-uniformly with s; and (iii) all lower-derivative couplings are scaled away. For s = 3 the limit yields the unique non-abelian spin 2?3?3 vertex found recently by two of the authors, thereby proving the uniqueness of the corresponding FV vertex. We extend the analysis to s = 4 and a class of spin 1?s?s vertices. The non-universality of the flat limit high-lightens not only the problematic aspects of higher-spin interactions with ? = 0 but also the strongly coupled nature of the derivative expansion of the fully nonlinear higher-spin field equations with ??0, wherein the standard minimal couplings mediated via the Lorentz connection are subleading at energy scales (|?|)1/2??E??Mp. Finally, combining our results with those obtained by Metsaev, we give the complete list of all the manifestly covariant cubic couplings of the form 1?s?s? and 2?s?s?, in Minkowski background.

Excimer laser processing of indium‐tin‐oxide films: An optical investigation

Abstract: dc sputtered indium‐tin‐oxide films have been excimer laser irradiated at subablation threshold fluences (<510 mJ/cm2). Optical characterization of irradiated products has been performed aiming at resolving the finer structure appearing in the IR–visible absorption spectra, as a function of laser fluence, and assigning such features to specific electronic defects which are produced upon irradiation. Four individual Gaussian‐like contributions to absorption spectra are identified at 0.7, 1.0, 1.6, and 2.6 eV, the intensity of which is observed to vary with fluence. Being absent in the original films and emerging in optical spectra at fluences exceeding 300 mJ/cm2, the 2.6 eV contribution is most characteristic to excimer laser processing and is responsible for the darkening of the film. Thermal model calculations reveal that such defects are produced only upon melting and fast resolidification of the film. The evolution of the chemistry actually taking place in the film upon irradiation is followed by x‐ra...

Indications of suppression of excited? States in Pb-Pb collisions at sNN2.76 TeV

Abstract: A comparison of the relative yields of Upsilon resonances in the mu(+) mu(-) decay channel in PbPb and pp collisions at a centre-of-mass energy per nucleon pair of 2.76 TeV, is performed with data collected with the CMS detector at the LHC. Using muons of transverse momentum above 4 GeV/c and pseudorapidity below 2.4, the double ratio of the Upsilon(2S) and Upsilon(3S) excited states to the Upsilon(1S) ground state in PbPb and pp collisions,(Upsilon(2S+3S)/Upsilon(1S)[PbPb])/(Upsilon(2S+3S)/Upsilon(1S)[pp]), is found to be 0.31 - 0.15 + 0.19 (stat.) +/- 0.03 (syst.). The probability to obtain the measured value, or lower, if the true double ratio is unity, has been calculated to be less than 1%.

Measurement of the atmospheric neutrino energy spectrum from 100 GeV to 400 TeV with IceCube

Abstract: A measurement of the atmospheric muon neutrino energy spectrum from 100 GeV to 400 TeV was performed using a data sample of about 18 000 up-going atmospheric muon neutrino events in IceCube. Boosted decision trees were used for event selection to reject misreconstructed atmospheric muons and obtain a sample of up-going muon neutrino events. Background contamination in the final event sample is less than 1%. This is the first measurement of atmospheric neutrinos up to 400 TeV, and is fundamental to understanding the impact of this neutrino background on astrophysical neutrino observations with IceCube. The measured spectrum is consistent with predictions for the atmospheric nu(mu) + (nu) over bar (mu) flux.