55209539
Characteristic Plane Method with Conical Correction
In ground-based cosmic ray experiments, the equalization of the transit time of signals coming from different parts of the apparatus is of crucial importance for the improvement of the angular resolution and accuracy. In the ARGO-YBJ experiment, this is achieved using the Characteristic Plane Method with conical correction, studied by both Monte Carlo simulation and real data and also checked with manual absolute calibration on a portion of the detector. By introducing conical correction in primary direction reconstruction, the systematics error existing in the off-line calibration with planar fit is successfully removed. Two subsequent construction phases of the detector have been considered: ARGO-42 and ARGO-104. During the calibration of ARGO-104, events with more than 1000 hits and with the core reconstructed inside the carpet were used in order to achieve a good reconstruction of the shower, that is the arrival direction and the core position. The results of the calibration concerning the two configurations, ARGO-42 and ARGO-104, are compared and discussed.
14464884
Detector time offset and off-line calibration in EAS experiments
In extensive air shower (EAS) experiments, the primary direction is reconstructed by the space–time pattern of secondary particles. Thus the equalization of the transit time of signals coming from different parts of the detector is crucial in order to get the best angular resolution and pointing accuracy allowed by the detector. In this paper an off-line calibration method is proposed and studied by means of proper simulations. It allows to calibrate the array repeatedly just using the collected data without disturbing the standard acquisition. The calibration method is based on the definition of a Characteristic Plane introduced to analyze the effects of the time systematic offsets, such as the quasi-sinusoidal modulation on azimuth angle distribution. This calibration procedure works also when a pre-modulation on the primary azimuthal distribution is present.
118376307
Search for GeV Gamma‐Ray Bursts with the ARGO‐YBJ Detector in Scaler Mode
The ARGO‐YBJ experiment is a full coverage array made of Resistive Plate Chambers (RPCs) operated in streamer mode to detect the extensive array showers (EASs). With large field of view (>2sr) and high duty cycle (>90%), the ARGO‐YBJ detector is the right ground‐based apparatus to detect VHE GRBs, while the high altitude (4300 m a.s.l) and scaler working mode enable it to detect GRBs in the GeV region as high energy follow‐up observation of satellites such as SWIFT. If a GRB signal is detected, the four scaler channels, which correspond to different energy thresholds, can provide further information on the energy spectrum and its cut‐off. More than 40 SWIFT GRBs were in ARGO‐YBJ field of view, no significant excess was detected till now.
118403311
Geometry and optics calibration of WFCTA prototype telescopes using star light
The Large High Altitude Air Shower Observatory project is proposed to study high energy gamma ray astronomy ( 40 GeV-1 PeV ) and cosmic ray physics ( 20 TeV-1 EeV ). The wide field of view Cherenkov telescope array, as a component of the LHAASO project, will be used to study energy spectrum and compositions of cosmic ray by measuring the total Cherenkov light generated by air showers and shower maximum depth. Two prototype telescopes have been in operation since 2008. The pointing accuracy of each telescope is crucial to the direction reconstruction of the primary particles. On the other hand the primary energy reconstruction relies on the shape of the Cherenkov image on the camera and the unrecorded photons due to the imperfect connections between photomultiplier tubes. UV bright stars are used as point-like objects to calibrate the pointing and to study the optical properties of the camera, the spot size and the fractions of unrecorded photons in the insensitive areas of the camera.
119179510
Properties and performance of two wide field of view Cherenkov/fluorescence telescope array prototypes
A wide field of view Cherenkov/fluorescence telescope array is one of the main components of the Large High Altitude Air Shower Observatory project. To serve as Cherenkov and fluorescence detectors, a flexible and mobile design is adopted for easy reconfiguring of the telescope array. Two prototype telescopes have been constructed and successfully run at the site of the ARGO-YBJ experiment in Tibet. The features and performance of the telescopes are presented. (C) 2010 Elsevier B.V. All rights reserved.
115310371
Preliminary results of the Moon shadow with ARGO-YBJ
137374294
Preliminary Lattice Design of the SSRF Storage Ring
117444261
The effect of high-order multipole imperfections on the LEP dynamic aperture
119282988
Dynamics of an interacting dark energy model in Einstein and loop quantum cosmology
We investigate the background dynamics when dark energy is coupled to dark matter in the Universe described by Einstein cosmology and loop quantum cosmology. We introduce a new general form of dark sector coupling, which presents a more complicated dynamical phase space. Differences in the phase space in obtaining the accelerated scaling attractor in Einstein cosmology and loop quantum cosmology are disclosed.
53550768
Asymptotic quasinormal modes of a coupled scalar field in the Garfinkle-Horowitz-Strominger dilaton spacetime
The analytic forms of the asymptotic quasinormal frequencies of a coupled scalar field in the Garfinkle-Horowitz-Strominger dilaton spacetime are investigated by using the monodromy technique proposed by Motl and Neitzke. It is found that the asymptotic quasinormal frequencies depend not only on the structure parameters of the background spacetime, but also on the coupling between the scalar fields and gravitational field. Moreover, our results show that only in the minimally coupled case, i.e., ξ tends to zero, the real parts of the asymptotic quasinormal frequencies agree with Hod's conjecture, T H In 3.
119252617
Holographic superconductor models with $RF^{2}$ corrections
We investigate the effect of the RF 2 correction on the holographic superconductor model in the background of AdS black hole. We find that, similar to the effect caused by the Weyl correction, the higher RF 2 correction term can make it easier for the scalar operator to condense and result in the larger deviations from the expected relation in the gap frequency. However, if a non-trivial hair for the black hole has been triggered, we observe that the RF 2 correction and the Weyl correction do play different roles in the behavior of the condensation, which can be used to support the existing findings. PACS numbers: 11.25.Tq, 04.70.Bw, 74.20.-z ∗ panqiyuan@126.com † csb3752@hunnu.edu.cn ‡ jljing@hunnu.edu.cn