远距离双心γ族事例

最近在甘巴拉山乳胶室中观测到一个独特的双心事例:K5618,它的能量ΣE_γ=547TeV,天顶角27°,每个核心的能量是E₁=428TeV,E₂=119TeV,相互间距离R₁₂=25.56cm.这样的事例予示着在超高能区有特大横动量的强子相互作用的讯息.     

用大规模铁乳胶室研究超高能γ族事例

用大规模铁乳胶室观测到ΣE_γ=7631TeV的大γ族事例,介绍了铁乳胶室观测大族的优点和族的各项特征,并与模拟计算结果作了比较.     

大气宇宙线中的高能γ线与强子

用中、日合作设置在甘巴拉山(海拔5500米,大气深度520g/cm²上的部分K6和K7厚铅乳胶室,研究了观测能量为10—50TeV的大气宇宙线中的高能γ线与强子.给出了它们的垂向流强、积分能谱、天顶角分布及其在大气中的衰减长度.将所得结果与过去的同类结果进行了比较.     

高山5500米超高能宇宙线强子特性的研究

利用乳胶室对高山(5500米)宇宙线强子特性进行了研究. 实验给出E_h=2~20TeV能区中强子簇射的微分能量谱指数β=(2.98±0.49), 簇射的垂直流强J(E_h≥3TeV)=(400±50)m)²﹒year﹒sr, 强子在大气中的衰减长度Λ=(104±16)g/cm², 强子和铅的平均核作用长度λ_h=(15.3±3.0)cm, 介子和铅的平均核作用长度λ_m(18.6±4.7)cm, 以及5500米高度的介子流强、核子流强的比例ε=(1.0±0.4).     

高山5500米超高能宇宙线强子的能谱

高能强子在大气中的传播对于研究初级宇宙线的能谱,超高能宇宙线与核的相互作用都是很有意义的。近几年来,我们在西藏甘巴拉山（5500米高度,大气深度是520克/厘米²）设置了乳胶室,对于宇宙线电磁成份的研究已有报道。本文对E_h^γ=3—50TeV的强子性质进行了初步的研究。测量了这个能区的垂直流强、积分能借、在Pb中的核作用平均长度及其在大气中的衰减长度。现将结果报道如下:     

西藏羊八井广延空气簇射阵列性能的Monte Carlo研究

本文用Monte Carlo方法研究西藏羊八井空气簇射阵列性能.确定好事例判选标准.簇射中心定位精度达3.4m.原初粒子到达方向角分辨率好于1.1°.原初粒子能量按lgE₀=lg(0.45ΣN_i)±0.226确定,其中E₀(TeV)为初级入射粒子能量,ΣN_i为FT探测器上探测到的粒子总数.     

在甘巴拉山上观测ΣEγ≥1000TeV的γ线族事例

介绍了甘巴拉山乳胶室实验中, 观测大族的初步结果. 讨论了ΣE_γ≥1000TeV γ线族的特性, 并与Monte Carlo模拟结果进行了比较.     

宇宙线超高能多核心族事例

本文报道了甘巴拉山乳胶室在核乳胶片上记录的宇宙线超高能多核心族事例KOE19(ΣE_γ≈1530TeV). 分析了事例的族现象特征, 并同其它大族事例进行比较. 把事例中的几个主要核心的特性同加速器和C喷注的实验结果以及TeV能区唯象QCD理论计算结果作了比较, 讨论了TeV能区超高能粒子强相互作用的一些特征.     

产生多个大横动量成份的超高能核作用事例

对甘巴拉山乳胶室得到的一个ΣE_γ=1300TeV的γ线族进行了分析, 这个事例是发生在乳胶室上方的核作用, 产生高度低于150m. 事例的中心部分由5个集团组成. 对此事例的特性进行了讨论.     

族事例多心结构现象分析

对传统的集团化方法进行了改进,采用扫描集团化方法对族事例进行处理,重新定义了多心结构事例的选择标准,通过多心结构事例实验数据与模拟计算结果的比较,研究超高能区核相互作用的规律.本文同时提出了用主集团的能量份额来辨认由初级质子所产生的大族事例(∑E_γ≥500TeV)的方法.     

Production of Charged Heavy Quarkonium-Like States at the LHC and Tevatron

We study prompt hadroproduction of the charged bottomonium-like states Zb± （10610） and Zb±（10650）, and the charged eharmonium-like states Zc± （3900） and Zc± （4020）, at the Tevatron and the LHC, provided that these states are S-wave hadronic molecules. Using two Monte Carlo event generators, Herwig and Pythia, to simulate the production of heavy meson pairs, we derive an order-of-magnitude estimate of the production rates for these four particles. Our estimates yield a cross section at the nb level for the Zb（10610） and Zb（10650）. The results for the Zc（3900） and Zc （4020） are larger by a factor of 2~30. These cross sections are large enough to be observed, and measurements at hadron colliders in the future will supplement the study using electron-positron collisions, and therefore allow to explore the mysterious nature of these exotic states.     

Rumsfeld hadrons

A missing link in the Standard Model is understanding hadrons, particles that respond to the strong interactions. In this article I summarise our knowledge in three classes, which are reminiscent of Donald Rumsfeld's (in)famous: ‘things that we know we know; things that we know we don't know; and things that we don't know that we don't know'. Recent discoveries in particle physics concerning strongly interacting hadrons fall into those categories. It is of course the third category that is the most tantalising, but lessons from the first two may help resolve the third.     

Fields and States of Hadrons Extended in the Microscopic Finslerian Space-Time

From a consideration of extended hadron structure in the microlocal anisotropic space-time, the mesonic and baryonic states with their internal quantum numbers such as strangeness, hypercharge, baryon number are constructed. The SU ₃ baryonic multiplets of baryons with spin (j + ) are generated from the SU ₃ mesonic multiplets of mesons with spin j. The meson–baryon mass differences are also derived here. The composite particle field of hadrons for the macroscopic space-time are obtained. In particular, the meson field and one particle meson state are considered here. These one particle hadron states of the macroscopic space-time also possess the quantum numbers (strangeness, hypercharge, etc.) which are regarded as the manifestations of the anisotropic nature of the microlocal space-time. The composite fields constructed here are usable in the reduction formulae of the S-matrix approach for strong interaction.     

Heavy-ion collisions

This is a short summary of the systematics observed in various heavy-ion experiments at CERN SPS energies.     

Semi-inclusive lepto-production of hidden-charm exotic hadrons

We investigate the semi-inclusive production of hidden-charm exotic states, including the \begin{document}$X(3872)$\end{document}, \begin{document}$Z_c$\end{document}, \begin{document}$Z_{cs}$\end{document} and pentaquark \begin{document}$P_c$\end{document} states, in lepton-proton scattering processes. These hadrons are close to the thresholds of a pair of charm and anticharm hadrons and are assumed to possess a hadronic molecular structure as their main feature. To provide order-of-magnitude estimates of the cross sections, we use Pythia to simulate the short-distance productions of the constituent hadrons, which then rescatter to form exotic hadrons. The estimates for the \begin{document}$X(3872)$\end{document} and \begin{document}$Z_c(3900)^\pm$\end{document} states are not in conflict with the upper limits measured in the COMPASS experiment for the exclusive photoproduction process. The results indicate that the considered hidden-charm states can be copiously produced at the proposed electron-ion colliders EicC and US-EIC.     

Identified hadron production in √s = 130 GeV Au-Au collisions at relativistic heavy-ion collider

Identified π^±,K ^±, p and -p transverse momentum spectra at mid-rapidity in √^sNN = 130 GeV Au-Au collisions were measured by the PHENIX experiment at RHIC as a function of collision centrality. Average transverse momenta increase with the number of participating nucleonsN _part similarly for all particle species. The multiplicity densities scale faster thanN _part. TheK ^± andp ^±yields per participant increase faster than the π^± yields. We combine the PHENIX neutral and charged pion measurement and find that in central collisions forp _T >-2 GeV/c,-p andp yields are comparable to or even exceed the pion yields.     

Method of estimation of hadron attenuation in leptoproduction from nuclei

Results of estimation of hadron attenuation in the process of leptoproduction from nuclei are presented, obtained on the basis of the improved numerical method proposed in [1] with allowance for predictions of the string model. Definition of the concepts of production time and formation time are given. The developed methodology of calculations is described. Plots of hadron attenuations versus the energy of the virtual photon and the fraction of energy retained by the hadron are presented.     

Electromagnetic cascade showers with the LPM effect in standard rock initiated by extremely high-energy (1015 eV to 1021 eV) gamma-rays

Summary High-energy neutrinos produce finally high-energy electromagnetic cascade showers. For the detectio of high-energy neutrinos, it is necessary to examine the behaviour of the electromagnetic cascade showers in the higher-energy region. It is well known that the LPM effect plays a decisive role in the electromagnetic cascade shower development at higher energies. In the present paper, the behaviour of electromagnetic cascade showers including the LPM effect (LPM showers) in standard rock is examined using the calculational technique developed by Fujimaki and Misaki. In order to clarify the characteristics of LPM showers, similar calculations are also carried out for cascade showers in the absence of the LPM effect (BH showers). Comparisons between the two different kinds of cascade showers are made over electron transition curves, track lengths and fractional dissipated energies. Finally, the strong deviation of LPM showers from the normal BH showers is emphasized.