共查询到20条相似文献,搜索用时 70 毫秒
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利用夸克统计模型和强子产额的实验数据,研究了 反应中的夸克对产生率、奇异抑制因子和重子介子比,得到了这些量随能量的变化规律. 相似文献
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基于相对论重离子碰撞所产生膨胀的热夸克-胶子等离子体火球模型,在考虑了火球内部的粒子数分布后,运用相对论流体力学方程,研究了s夸克和K-介子的产生率,结果表明对总的s夸克和K-介子产生率有很大地增强. 相似文献
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利用夸克统计模型和强子产额的实验数据,研究了pp反应中的夸克对产生率、奇异抑制因子和重子介子比,得到了这些量随能量s的变化规律. 相似文献
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从单胶子交换正反夸克对产生模型出发,计算了N-N相互作用中方盒图的等效两介子交换势,它随r的变化关系与唯象σ介子交换势随r的变化关系的趋势是一致的. 相似文献
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本文对瞬时近似的夸克-反夸克体系的Bethe-Salpeter方程中的γ-矩阵给出正确的Gordon约化的结果,并恰当地考虑了方程中投影算子及B-S振幅的小分量的贡献.在此基础上推导出准至p2/m2级近似的B-S方程的正确形式.进而利用B-S振幅的归一化条件,找到了B-S振幅与Pauli-Schrodinger波函数之间的关系.据此求得了包含相对论修正的Pauli-Schrodinger方程.利用变分法求解此方程,得到了与实验符合较好的介子谱. 相似文献
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建立了一个夸克交换模型和提出了一个夸克-反夸克湮灭模型来研究介子-介子散射。从量子色动力学我们得到一个依赖于温度的夸克作用势。从微扰量子色动力学推导对应于夸克-反夸克湮灭和产生的跃迁势。模型给出基态介子质量的实验值,并且在玻恩近似下能说明真空中阈能附近的π-π弹性散射相移的实验值。从S矩阵元出发,推导散射的跃迁振幅和截面公式。计算出涉及π,ρ,K,K*的反应的非极化截面。发现这些截面具有强烈的温度依赖性。We have established a quark-interchange model and have proposed a quark-antiquark annihilation model to study meson-meson scattering. From QCD we obtain a temperature-dependent quark potential. The transition potential corresponding to quark-antiquark annihilation and creation is derived in perturbative QCD. The experimental ground-state meson masses are reproduced and the experimental data of elastic phase shifts for ππ scattering near the threshold energy in vacuum can be accounted for in the Born approximation. Starting from S-matrix element, we derive the transition amplitude and the cross section for the scattering. Unpolarised cross sections for reactions involving π, ρ, K and K* are calculated. Remarkable temperature dependence of the cross sections is found. 相似文献
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The dominant decay modes of charged top-pions (π±t ) are tb or ~b. We consider the single production ofcharged top-pions in association with a top quark via e+ e- annihilation and calculate the production cross section of theprocesses e+ e- → t-bπ+ (tb-π-) at the leading order. We find that it can reach 1.2 fb with reasonable parameter values.The charged top-pions may be detected via the channel tbπ± in the future high energy e+ e- colliders. 相似文献
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The single charged top-pion production processes
e+e-→t\bar{b}Πt- and
e+e-→
W+Πt- are studied in the framework of top-color-assisted
technicolor (TC2) model. Our studies show that the cross section
σ(e+e-→t\bar{b}Πt-) reaches the level of tens of fb and
σ(e+e-→W+Πt-) reaches the
level of a few fb. With the yearly integrated luminosity of
L~500 fb-1 expected at the planned colliders, one
could collect thousands of charged top-pion of events via the process
e+e-→t\bar{b}Πt- and hundreds of events via the process
e+e-→W+Πt-. The flavor changing decay
mode Πt-→b\bar{c} is the best channel to detect
charged top-pion due to the clean SM background. With a large
number of events and the clean background, the charged top-pion
should be observable at the planned colliders. Therefore, our
studies in this paper can help us to search for charged top-pion,
and furthermore, to test the TC2 model. 相似文献
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We studied the charged top-pion in the topcolor assisted technicolor model (TC2). If the charged top-pions are heavy, mπt 〉 mt +mb, they will decay mainly via the channel πt^+ → tb. We also calculated the production of charged top-pion at the Tevatron and LHC. The cross section can reach to 100 fb at the Tevatron and dozens of pb at the LHC depending on the mass of the top-pion. 相似文献
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HOU Hong-Sheng 《理论物理通讯》2009,52(6):1036-1040
We studied the charged top-pion in the topcolor assisted technicolor model (TC2). If the charged top-pions are heavy, mπt >mt+mb, they will decay mainly via the channel π+t → t \bar{b}. We also calculated the production ofcharged top-pion at the Tevatron and LHC. The cross section can reach to 100 fb at the Tevatron and dozens of pb at the LHC depending on the mass of the top-pion. 相似文献
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WANG Xue-Lei LI Ji-Tao LIU Su-Zhen 《理论物理通讯》2007,48(5):891-894
In the minimal supersymmetric standard model with R-parity violation, the lepton number violating top quark interactions can contribute to the top pair production at a linear collider via tree-level u-channel squark exchange diagrams. We calculate such contributions and find that in the allowed range of these R-violating couplings, the top pair production rate as well as the top quark polarization and the forward-backward asymmetry can be significantly altered. By comparing the unpolarized beams with the polarized beams, we find that the polarized beams are more powerful in probing such new physics. 相似文献
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XU Wen-Na WANG Xue-Lei XIAO Zhen-Jun 《理论物理通讯》2008,49(1):193-198
In the framework of topcolor-assisted technicolor (TC2) model, there exist tree-level flavor-changing (FC) couplings, which can result in the loop-level FC coupling tcg. Such tcg coupling can contribute significant clues at the forthcoming Large Hadron Collider (LHC) experiments. In this paper, based on the TC2 model, we study some single t-quark production processes involving tcg coupling at the Tevatron and LHC: pp(pp) → tq (q = u, d, s), tg. We calculate the cross sections of these processes. The results show that the cross sections at the Tevatron are too small to observe the signal, but at the LHC it can reach a few pb. With the high luminosity, the LHC has considerable capability to find the single t-quark signal produced via some FC processes involving coupling tcg. On the other hand, these processes can also provide some valuable information of the coupling tcg with detailed study of the processes and furthermore provide the reliable evidence to test the TC2 model 相似文献
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In this paper, charged Higgs pair production through l^+l^- → H^+ H^-, where l = e or μ, is studied within the framework of a general Two Higgs Doublet Model (2HDM). The analysis is relevant to a future e^+e^- or μ^+ μ^- collider operating at center of mass energy of √s = 500 GeV. Two different scenarios of small and large a values are studied. Here a is the parameter, which diagonMizes the neutral CP-even Higgs boson mass matrix. Within the Minimal Supersymmetric Standard Model (MSSM), cross section of this process is almost the same at e+ e- and #+#- colliders. It is shown that at e^+e^- eolliders within a general 2HDM, cross section is not sensitive to the mass of neutral Higgs bosons, however, it can acquire large values up to several picobarn at μ^+μ^- colliders with the presence of heavy neutral Higgs bosons. A scan over Higgs boson mass parameter space is performed to analyze the effect of large masses of neutral Higgs bosons involved in the s-channel propagator and thus in the total cross section of this process. 相似文献
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Based on calculating the contributions of the littlest Higgs model with T-parity (called LHT model) to the anomalous top coupling tqγ (q=u or c), we consider single top production via the t-channel partonic process eq → et in ep collisions. Our numerical results show that the production cross section in the LHT model can be significantly enhanced relative to that in the standard model (SM). 相似文献
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M. Klein 《Progress in Particle and Nuclear Physics》2008,61(2):343-393
From 1992 to 2007, HERA, the first electron-proton collider, operated at cms energies of about 320 GeV and allowed the investigation of deep-inelastic and photoproduction processes at the highest energy scales accessed thus far. This review is an introduction to, and a summary of, the main results obtained at HERA during its operation. 相似文献
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The top triangle moose (TTM) model, which can be seen as the deconstructed version of the topcolor-assisted technicolor (TC2) model, predicts the existence of the charged top-pions πt± in low energy spectrum. In the context of this model, we consider photoproduction of πt± via the subprocesses γb → tπt- and γb → tπt+ at the large hadron-electron collider (LHeC), in which high energy photon beams are generated by using the Compton backscatting method. We find that, as long as the charged top-pions are not too heavy, they can be abundantly produced via γb collision. 相似文献