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
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
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
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
18953757
Eternal chaotic inflation is prohibited by the weak gravity conjecture
We investigate whether eternal chaotic inflation can be achieved when the weak gravity conjecture is taken into account. We show that even assisted chaotic inflation with potential λ4 or m22 cannot be eternal. The effective field theory description for the inflaton field breaks down before inflation reaches the eternal regime. We also find that the total number of e-folds is still bounded by the inflationary entropy for the assisted inflation.
118660680
Canny Algorithm: A New Estimator for Primordial Non-Gaussianities
We utilize the Canny edge detection algorithm as an estimator for primordial non-Gaussianities. In preliminary tests on simulated sky patches with a window size of 57 degrees and multipole moments $l$ up to 1024, we find a $3\sigma$ distinction between maps with local non-Gaussianity $f_{NL}=350$ (or $f_{NL}=-700$) and Gaussian maps. We present evidence that high resolution CMB studies will strongly enhance the sensitivity of the Canny algorithm to non-Gaussianity, making it a promising technique to estimate primordial non-Gaussianity.
95672151
Studies of neutron emission from relativistic nuclear interactions
Abstract Studies were carried out on the yields and spatial distributions of secondary neutrons produced in the relativistic nuclear interactions of 1.5 GeV to 14.4 GeV projectiles p, d and α-particles with targets Pb and U/Pb. CR-39 track detectors were used to measure the neutrons. It shows that: (1) Secondary neutrons are produced in the whole length of Pb or U targets having a thickness of 20 cm. The neutron intensities produced by proton bombardments are reduced along the proton beam direction in the targets. The higher the energy of protons, the lower the reduction rate of the neutrons. The reduction rate of neutrons in U target is higher than in Pb target for the same energy of protons. (2) The radial intensities of neutrons decrease as the distance increases from the target central line. (3) The neutron yield in U target by proton bombardments is ∼55% higher than in Pb target. (4) The ratio of neutron yield by 14.4 GeV α to 7.3 GeV d bombardment in Pb target is 1.74 ± 0.20.
108903001
Test results of heavily irradiated Si detectors
Abstract A large use of silicon microstrip detectors is foreseen for the intermediate part of the CMS tracker. A specific research and development program has been carried out with the aim of finding design layouts and technological solutions for allowing silicon microstrip detectors to be reliably used on a high radiation level environment. As a result of this work single sided, AC-coupled, polysilicon biased, 300 μ m thick, p + on n substrate detectors were chosen. Irradiation tests have been performed on prototypes up to fluence 2×10 14  n/cm 2 . The detector performances do not significantly change if the detectors are biased well above the depletion voltage. S / N is reduced by less than 20%, still enough to insure a good efficiency and space resolution. Multiguard structures has been developed in order to reach high voltage operation (above 500 V).
120991936
SIMULATION STUDIES OF TRIGGER DECISION CRITERION FOR THE ALICE/PHOS
This paper gives some results about trigger decision criterion of the ALICE PHOton Spectrometer (PHOS) by Monte Carlo simulations, including four parts: (1) an overview of trigger decision criterion of PHOS; (2) the energy reconstruction performance of PHOS; (3) the selection of trigger threshold and the event trigger efficiency distribution; (4) the photon event trigger rate of PHOS in p–p interactions and Pb–Pb collisions.