122821031
Spectral index of high-energy cosmic rays by the Compton-Getting effect at solar time frame with the Tibet air shower array
We report on the spectral index of cosmic rays around 10 TeV energy region obtained by observation of the Compton-Getting anisotropy due to the terrestrial orbital motion around the Sun with the Tibet III air shower array during the period from 1999 to 2005. The spectral index has turned out to be 2.99 ± 0.54 , which is consistent with 2.74 by the direct energy spectrum measurement. This method is a new approach to measure the spectral index and is complementary to the conventional energy spectrum measurement.
110395885
Analysis of Emulsion Chambers in Tibet Hybrid Experi- ment Using the Image Scanner
A hybrid experiment consisting of emulsion chambers and an air shower array was carried out by the Tibet ASγ collaboration to investigate primary proton spectrum in the knee region. A new method of automatic analysis of emulsion chamber using the image scanner was developed and applied to this experiment. In this paper, the result of analysis on emulsion chamber part in hybrid experiment is presented. It is shown sufficiently high efficiency of the γfamily detection is realized by automatic analysis both in energy and geometrical resolutions. 1. Introduction Emulsion chamber is a powerful detector for γ-rays in TeV region with high spacial and energy resolution. The Tibet ASγ collaboration [2],[3] used it with combination of burst detectors and an air shower array for the purpose of measuring the energy flow characteristics of the air shower core in investigating the proton spectrum in the knee region. The total number of X-ray films of size 40 cm × 50 cm used for 3 years experiment with area of 80 m 2 amounts to 7200 sheets. It is a huge work to analyze them by traditional method where each
124994910
Expected Event Rate of Subhundred-GeV Gamma Ray Bursts using the Tibet-III Air Shower Array with Single Particle Counting Technique
We calculate the expected event rate of subhundred-GeV gamma-ray bursts using the Tibet-III air shower array with single particle counting technique. The calculation is done under reasonable assumptions that the attenuation effect of gamma rays in the intergalactic space as well as the distributions of redshift, luminosity and emission time of GRBs.
129939642
Primary proton spectrum in the knee region observed by the Tibet hybrid experiment
Proton spectrum in the knee region is obtained from the Tibet hybrid experiment consisting of the emulsion chambers and the Tibet II air shower array. The proton spectrum in the energy range > 10 15 eV shows the steepening of spectrum with power index -3.14±0.10 being 3.9σ deviation from that of direct observations below a few hundred TeV. Another estimate using a proton dominant chemical composition model also results in power index of -3.06±0.09 being 3.6σ
162177595
Observation of Multi-TeV Gamma Rays from Mrk 421 and Search for Other BL Lac Objects with the Tibet-III Air Shower Array The Tibet
122942175
An upper limit on cosmic-ray anti-p/p flux ratio estimated by the moon's shadow with the TIBET III air shower array
The Tibet ASγ Collaboration M. Amenomori, S. Ayabe, S.W. Cui, Danzengluobu, L.K. Ding, X.H. Ding, C.F. Feng, Z.Y. Feng, X.Y. Gao, Q.X. Geng, H.W. Guo, H.H. He, M. He, K. Hibino, N. Hotta, Haibing Hu, H.B. Hu, J. Huang, Q. Huang, H.Y. Jia, F. Kajino, K. Kasahara, Y. Katayose, K. Kawata, T. Kido, Labaciren, G.M. Le, J.Y. Li, H. Lu, S.L. Lu, X.R. Meng, K. Mizutani, J. Mu, H. Nanjo, M. Nishizawa, M. Ohnishi, I. Ohta, T. Ouchi, S. Ozawa, J.R. Ren, T. Saito, M. Sakata, T. Sasaki, M. Shibata, A. Shiomi, T. Shirai, H. Sugimoto, K. Taira, M. Takita, Y.H. Tan, N. Tateyama, S. Torii, H. Tsuchiya, S. Udo, T. Utsugi, B.S. Wang, H. Wang, X. Wang, Y.G. Wang, L. Xue, Y. Yamamoto, X.C. Yang, Z.H. Ye, G.C. Yu, A.F. Yuan, T. Yuda, H.M. Zhang, J.L. Zhang, N.J. Zhang, X.Y. Zhang, Y. Zhang, Zhaxisangzhu, and X.X. Zhou (1) Dept. of Phys., Hirosaki Univ., Hirosaki, Japan (2) Dept. of Phys., Saitama Univ., Saitama, Japan (3) IHEP, CAS, Beijing, China (4) Dept. of Math. and Phys., Tibet Univ., Lhasa, China (5) Dept. of Phys., Shandong Univ., Jinan, China (6) Inst. of Modern Phys., SW Jiaotong Univ., Chengdu, China (7) Dept. of Phys., Yunnan Univ., Kunming, China (8) Faculty of Eng., Kanagawa Univ., Yokohama, Japan (9) Faculty of Ed., Utsunomiya Univ., Utsunomiya, Japan (10) Dept. of Phys., Konan Univ., Kobe, Japan (11) Faculty of Systems Eng., Shibaura Inst. of Technology, Saitama, Japan (12) Dept. of Phys., Yokohama Natl. Univ., Yokohama, Japan (13) ICRR, Univ. of Tokyo, Kashiwa, Japan (14) CSSAR, CAS, Beijing, China (15) NII, Tokyo, Japan (16) Tokyo Metropolitan Coll. of Aeronautical Eng., Tokyo, Japan (17) Shonan Inst. of Technology, Fujisawa, Japan
211256085
Effects of Tune Modulation on Particles Trapped in 1D Resonance Islands
The response of particles trapped in 1D resonance islands to betatron tune modulation resembles, yet is not equivalent to, that of a parametric resonant system. Experimental data obtained at Indiana University Cyclotron Facility for the 4th order resonance islands has confirmed this characteristic feature. The beam, driven by betatron tune modulation, was observed for the first time to travel from near the center of resonance islands toward the separatrix. The experimental data are characterized by the onset of large response at a critical modulation amplitude and frequency, which are compared with theoretical models. Possible future experiments are suggested. 41.85.-p,05.45+b,29.2O.Dh *Work supported in part by grants from the National Science Foundation NSF PHY-9221402 and from the U.S.DoE DE-FGO2-93ER40801; a IUCF, Indiana University, Bloomington, IN 47405; b The SSC laboratory, 2550 Beckleymeade Avenue, Dallas, TX 75X37-3946; ’ Fermilab, P.0. Box 500, Batavia, IL 60510.
42340868
New limits on the ultrahigh energy cosmic neutrino flux from the ANITA experiment.
We report initial results of the first flight of the Antarctic Impulsive Transient Antenna (ANITA-1) 2006-2007 Long Duration Balloon flight, which searched for evidence of a diffuse flux of cosmic neutrinos above energies of E(nu) approximately 3 x 10(18) eV. ANITA-1 flew for 35 days looking for radio impulses due to the Askaryan effect in neutrino-induced electromagnetic showers within the Antarctic ice sheets. We report here on our initial analysis, which was performed as a blind search of the data. No neutrino candidates are seen, with no detected physics background. We set model-independent limits based on this result. Upper limits derived from our analysis rule out the highest cosmogenic neutrino models. In a background horizontal-polarization channel, we also detect six events consistent with radio impulses from ultrahigh energy extensive air showers.
120571188
Large Synoptic Survey Telescope: Dark Energy Science Collaboration
This white paper describes the LSST Dark Energy Science Collaboration (DESC), whose goal is the study of dark energy and related topics in fundamental physics with data from the Large Synoptic Survey Telescope (LSST). It provides an overview of dark energy science and describes the current and anticipated state of the field. It makes the case for the DESC by laying out a robust analytical framework for dark energy science that has been defined by its members and the comprehensive three-year work plan they have developed for implementing that framework. The analysis working groups cover five key probes of dark energy: weak lensing, large scale structure, galaxy clusters, Type Ia supernovae, and strong lensing. The computing working groups span cosmological simulations, galaxy catalogs, photon simulations and a systematic software and computational framework for LSST dark energy data analysis. The technical working groups make the connection between dark energy science and the LSST system. The working groups have close linkages, especially through the use of the photon simulations to study the impact of instrument design and survey strategy on analysis methodology and cosmological parameter estimation. The white paper describes several high priority tasks identified by each of the 16 working groups. Over the next three years these tasks will help prepare for LSST analysis, make synergistic connections with ongoing cosmological surveys and provide the dark energy community with state of the art analysis tools. Members of the community are invited to join the LSST DESC, according to the membership policies described in the white paper. Applications to sign up for associate membership may be made by submitting the Web form at http://www.slac.stanford.edu/exp/lsst/desc/signup.html with a short statement of the work they wish to pursue that is relevant to the LSST DESC.
56436935
Current observational constraints on cosmic doomsday
In a broad class of dark energy models, the universe may collapse within a finite time tc. Here we study a representative model of dark energy with a linear potential, V () = V0(1+α). This model is the simplest doomsday model, in which the universe collapses rather quickly after it stops expanding. Observational data from type Ia supernovae (SNe Ia), cosmic microwave background anisotropy (CMB), and large scale structure (LSS) are complementary in constraining dark energy models. Using the new SN Ia data (the Riess sample), the CMB data from WMAP, and the LSS data from 2dF, we find that the collapse time of the universe is (24) Gyr from today at 68% (95%) confidence.
119871313
The BESIII muon identification system
The muon identification system of BESIII experiment at the IHEP is described. The muon counter (MUC) is composed of resistive plate chambers (RPCs) working in self-quenching streamer mode with the gas mixture Ar/C(2)F(4)H(2)/C(4)H(10)=50/42/8. The design, the construction, the mass production and the quality control result of the detectors are described in detail. The paper also presents the performance of the bare RPCs and the superlayer modules with cosmic rays. Finally, the subsystems of MUC, including the RPC superlayer modules, the gas systems, the HV and LV system and the readout electronic system, are also presented. (C) 2009 Elsevier B.V. All rights reserved.