排序方式: 共有72条查询结果,搜索用时 15 毫秒
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The KIMS collaboration Y. S. Yoon H. K. Park H. Bhang J. H. Choi S. Choi I. S. Hahn E. J. Jeon H. W. Joo W. G. Kang B. H. Kim G. B. Kim H. J. Kim K. W. Kim S. C. Kim S. K. Kim Y. D. Kim Y. H. Kim H. S. Lee J. H. Lee J. K. Lee D. S. Leonard J. Li S. S. Myung S. L. Olsen J. H. So 《Journal of High Energy Physics》2016,2016(6):11
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Detailed comparisons of antihydrogen with hydrogen promise to be a fruitful test bed of fundamental symmetries such as the CPT theorem for quantum field theory or studies of gravitational influence on antimatter. With a string of recent successes, starting with the first trapped antihydrogen and recently resulting in the first measurement of a quantum transition in anti-hydrogen, the ALPHA collaboration is well on its way to perform such precision comparisons. We will discuss the key innovative steps that have made these results possible and in particular focus on the detailed work on positron and antiproton preparation to achieve antihydrogen cold enough to trap as well as the unique features of the ALPHA apparatus that has allowed the first quantum transitions in anti-hydrogen to be measured with only a single trapped antihydrogen atom per experiment. We will also look at how ALPHA plans to step from here towards more precise comparisons of matter and antimatter. 相似文献
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Zhang C Kohl M Akdogan T Alarcon R Bertozzi W Booth E Botto T Calarco JR Clasie B Crawford C DeGrush A Dow K Farkhondeh M Fatemi R Filoti O Franklin W Gao H Geis E Gilad S Hasell D Karpius P Kolster H Lee T Maschinot A Matthews J McIlhany K Meitanis N Milner R Rapaport J Redwine R Seely J Shinozaki A Sindile A Širca S Six E Smith T Tonguc B Tschalär C Tsentalovich E Turchinetz W Xiao Y Xu W Zhou ZL Ziskin V Zwart T;BLAST collaboration 《Physical review letters》2011,107(25):252501
We report a precision measurement of the deuteron tensor analyzing powers T(20) and T(21) at the MIT-Bates Linear Accelerator Center. Data were collected simultaneously over a momentum transfer range Q=2.15-4.50 fm(-1) with the Bates Large Acceptance Spectrometer Toroid using a highly polarized deuterium internal gas target. The data are in excellent agreement with calculations in a framework of effective field theory. The deuteron charge monopole and quadrupole form factors G(C) and G(Q) were separated with improved precision, and the location of the first node of G(C) was confirmed at Q=4.19±0.05 fm(-1). The new data provide a strong constraint on theoretical models in a momentum transfer range covering the minimum of T(20) and the first node of G(C). 相似文献
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L. Nozka M. Hrabovsky M. Bohacova M. Palatka D. Mandat for AIRFLY collaboration 《Optik》2009,120(12):619-622
This paper refers to the construction and utilization of the chamber that has been used for measurement of fluorescence yield within the frame of the project AIRFLY. The chamber was designed to simulate some physical conditions in high levels of the atmosphere, particularly pressure, temperature and humidity. The aim of the AIRFLY (AIR FLuorescence Yield) project is to simulate and to measure the process of the fluorescence and Cherenkov emission produced by impact of high-energy cosmic rays (UHECR) on molecules of nitrogen in high levels of the atmosphere. This is required for calibration of fluorescence detectors (FDs) dedicated for monitoring particles of these energies by means of fluorescence measurements. 相似文献
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The inclusive production of electron-positron pairs in proton-proton and deuteron-proton collisions at a beam kinetic energy
of 1.25 GeV per nucleon was studied with the HADES (High Acceptance Dielectron Spectrometer) detector. The main objective
of the deuteron-proton experiment was to investigate pair production in quasifree neutron-proton collisions. In the invariant-mass
region M > 140 MeV/c
2, the invariant-mass spectrum determined in this channel shows a significant enhancement of the pair yield in relation to
that in the case of proton-proton collisions. 相似文献
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王友宝 苏俊 韩治宇 唐兵 崔保群 葛涛 吕银龙 陈志强 郭冰 李鑫悦 李云居 李志宏 连钢 马田丽 马鹰俊 谌阳平 苏毅 王春光 吴弘毅 颜胜权 曾晟 郑云 周超 党永乐 付光永 何阳帆 刘伏龙 吴笛 张天爵 柳卫平 BRIF合作组 《原子核物理评论》2018,35(4):445-449
北京放射性离子束装置(Beijing Radioactive Ion-beam Facility,BRIF)是基于在线同位素分离器技术的国家大科学平台。在BRIF装置上利用100 MeV的质子束轰击较厚的反应靶产生放射性核素;反应产物经离子源电离和在线分离,在线同位素分离段可引出100~300 keV的放射性核束,质量分辨率达20 000。在基金委科学仪器基础研究专项的支持下,建成了多用途的衰变实验终端,包括束流传输管道、通用靶室、带电粒子和γ探测器、集成电子学和数据获取系统等。利用100 MeV的质子束轰击MgO厚靶产生了流强高达1×105 pps的20Na放射性核束。通过高效率地同时测量β,γ和α,第一次直接观测到20Na非常稀有的β-γ-α衰变模式。Beijing Radioactive Ion-beam Facility(BRIF) has been commissioned as the national Radioactive Ion Beam(RIB) facility based on the Isotope Separator On Line(ISOL) technique since 2016. At BRIF, the radioactive nuclides are produced by the proton beam of 100 MeV bombarding a thick-target, the reaction products diffusing out of the target are ionized by an ion source and delivered to the online mass separator. In addition to the post-accelerated radioactive ion beams, BRIF can provide low-energy ISOL beams of 100 to 300 keV with a mass resolution of 20 000. A general-purpose decay station has been built including the ISOL beam transport line, a conventional reaction chamber, charge-particle and γ detectors with integrated electronics and data acquisition system. An intense 20Na ISOL beam up to 1×105 pps was produced by using the 100 MeV proton beam bombarding a MgO thick target. With high-efficiency measurements of β, γ and α simultaneously, very rare β-γ-α decay mode in 20Na has been directly observed for the first time in the present work. 相似文献
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We present the survey of the main tasks in upgrading the hadron endcap (HE) calorimeters of the CMS experiment at LHC. The results of the HE upgrade during the LHC Long Shutdown (2013–2014) and plans for upgrade during LHC Extended Year End Technical Stop (December 2016–May 2017) are discussed. 相似文献