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showing 10 items of 925 documents

Identifying clouds over the Pierre Auger Observatory using infrared satellite data

2013

We describe a new method of identifying night-time clouds over the Pierre Auger Observatory using infrared data from the Imager instruments on the GOES-12 and GOES-13 satellites. We compare cloud. identifications resulting from our method to those obtained by the Central Laser Facility of the Auger Observatory. Using our new method we can now develop cloud probability maps for the 3000 km(2) of the Pierre Auger Observatory twice per hour with a spatial resolution of similar to 2.4 km by similar to 5.5 km. Our method could also be applied to monitor cloud cover for other ground-based observatories and for space-based observatories. (C) 2013 Elsevier B.V. All rights reserved.

[PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE][PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM]Atmospheric MonitoringSatellitesInfraredAstronomyCloud coverFOS: Physical sciencesAtmospheric monitoring01 natural sciencesCiencias de la Tierra y relacionadas con el Medio AmbienteAuger//purl.org/becyt/ford/1 [https]//purl.org/becyt/ford/1.5 [https]ObservatoryClouds0103 physical sciencesExtensive air showers010306 general physicsDETECTORInstrumentation and Methods for Astrophysics (astro-ph.IM)Image resolutionCiencias ExactasPhysicsPierre Auger ObservatoryUHE Cosmic Rays atmosphere010308 nuclear & particles physicsPhysics[SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE]FísicaAstronomyPierre Auger ObservatoryAstronomy and AstrophysicsUltra-high energy cosmic rays[SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM]INFRAVERMELHOExperimental High Energy PhysicsComputingMethodologies_DOCUMENTANDTEXTPROCESSINGPierre Auger observatoryultra-high energy cosmic rays; Pierre Auger Observatory; extensive air showers; atmospheric monitoring; clouds; satellitesFísica nuclearSatelliteCentral Laser FacilityExtensive Air ShowersAstrophysics - Instrumentation and Methods for AstrophysicsMeteorología y Ciencias AtmosféricasSYSTEMCIENCIAS NATURALES Y EXACTASAstroparticle Physics

researchProduct

The two-photon decay of X(6900) from light-by-light scattering at the LHC

2022

The LHCb Collaboration has recently discovered a structure around 6.9 GeV in the double-$J/\psi$ mass distribution, possibly a first fully-charmed tetraquark state $X(6900)$. Based on vector-meson dominance (VMD) such a state should have a significant branching ratio for decaying into two photons. We show that the recorded LHC data for the light-by-light scattering may indeed accommodate for such a state, with a $\gamma \gamma$ branching ratio of order of $10^{-4}$, which is larger even than the value inferred by the VMD. The spin-parity assignment $0^{-+}$ is in better agreement with the VMD prediction than $0^{++}$, albeit not significantly at the current precision. Further light-by-light…