共查询到20条相似文献,搜索用时 15 毫秒
1.
We present recent results from BABAR experiment for D0-D0 mixing measurements. Mixing parameters can be measured in different ways using different D0 decay modes, here we discuss the most sensitive analyses such as D0→K+π- where we had the first evidence of charm mixing, the measurement of the ratio of lifetimes of the decays D0→K+K- and D0→π+π- relative to D0→K-π+, the time dependent Dalitz plot analysis of D0→K+π-π0. New limits on CP-violating time-integrated asymmetries in D0→K+K- and D0→π+π- are also discussed. The analyses presented are based on 384 fb-1 data collected with the BABAR detector at the PEP-II asymmetric B Factory. 相似文献
2.
本文利用(0-3/2)电磁束缚系统相对论协变的近似B-S波函数和复合粒子量子场论的微扰展开理论, 分别计算了(π+Ω-)原子的库仑裂解截面与衰变几率. 高能(π+Ω-)原子在原子核屏蔽库仑场中的裂解截面为σ=Z4/3×2.9×10-18cm2, 衰变几率的计算结果为w[(π+Ω-)→π+Λ0K-]/w[Ω-→Λ0K-]=1+O(α). 相似文献
3.
4.
本文应用复合粒子量子场论的微扰展开式和相对论性的(π&;#177;μ?)、(K&;#177;μ?)的B.S.波函数,计算了在原子核屏蔽库仑场中高能(π&;#177;μ?)、(K&;#177;μ?)原子的裂解能谱和截面。在极端相对论近似下,对大多数原子核,它们的裂解截面分别约为10-18cm2和10-17cm2。利用同样的波函数,还计算了(π&;#177;μ?)→π0+vμ(vμ),(K&;#177;μ?)→K0+vμ(vμ),以及(π&;#177;μ?)→μ++μ-+vμ(vμ),(K&;#177;μ?)→μ++μ-+vμ(vμ)的衰变几率。 相似文献
5.
6.
二价Ba2+、Pb2+和四价Ti4+在硼硅酸盐玻璃系统中对Li+/Na+离子交换的影响 总被引:2,自引:1,他引:1
本文讨论了在硼硅酸盐玻璃系统中引入二价Ba2+、Pb2+和四价Ti4+后,由于Pb2+和Ti4+配位结构的变化,引起Pb2+、Ti4+场强及其与O2-离子间距的变化,对Li+/Na+离子交换产生影响,从而改变折射率差值(ΔN)和折射率分布. 相似文献
7.
8.
在以前工作的基础上,计算了飞行 K-奇异交换反应9Be(K-,π-)A9Be 和13C(K-,π-)A13C 的角分布.在平面波冲量近似下,计算了协同产生反应到达超核 A9Be、A13C 的奇异相似态和超对称态的微分截面的相对比,并且估算了这些微分截面绝对值.根据这些计算,讨论了通过奇异交换反应和协同产生反应产生超对称态的可能性. 相似文献
9.
10.
用40Ca区域的有效g因子计算了40Ca±1核的l-禁戒M1跃迁强度。结果解释了39K,41K的异常大的l-禁戒M1跃迁强度。对39K,41K和39Ca,41Ca的跃迁强度的差别作了定性的解释。 相似文献
11.
12.
13.
14.
P. Pakhlov 《中国物理 C》2008,32(6):488-491
We present a search for new charmonium like states in e+e- annihilation using the initial-state radiation and the process e+e-J/ψD(*)D(*). The analyses are based on a huge data sample recorded near the Υ(4s) resonance with the Belle detector at the KEKB e+e- asymmetric-energy collider. 相似文献
15.
The cross sections for e+e-→π+π-J/ψ, π+π-ψ(2S), K+K-J/ψ, DD, D0D-+π++c.c., D*D+c.c., and D*D* are measured using data sample collected on or near the Υ(4S) resonance with the Belle detector at KEKB. A peak near 4.25GeV/c2, corresponding to the so called Y(4260), is observed in π+π-J/ψ final state. In addition, there is another cluster of events at around 4.05GeV/c2. Two resonant structures are observed in the π+π-ψ(2S) invariant mass distribution, one at 4361±9±9MeV/c2 with a width of 74±15±10MeV/c2, and another at 4664±11±5MeV/c2 with a width of 48±15± 3MeV/c2. The rich structures observed in all these final states indicate that our understanding of the vector charmonium states above the open charm threshold is still poor, let alone the other possible dynamics such as charmonium hybrids or final state re-scattering and so on. 相似文献
16.
本工作采用金硅面垒型半导体探测器和固体径迹探测器测量了57.0—73.0MeV 12C+169Tm, 175Lu, 181Ta, W, Re, Pt, 197Au, Pb和209Bi裂变反应碎片角分布和裂变激发函数. 由相当于全动量转移的裂变事件的碎片角分布统计理论直接确定了全熔合反应截面σfu, 从而获得了作为激发能函数的<Γf/Γn>实验值. 与理论计算符合得到裂变位垒高度, 标准偏差为2.5MeV. 实验上确定的裂变位垒与非旋转液滴模型计算值相符合. 用同样方法, 我们还分析了已经发表了的12C+174Yb, 12C+198Pt, 16O+142Nd, 16O+170Er, 16O+181Ta和18O+192Os裂变反应激发函数, 研究了裂变位垒随裂变核质量数A的变化, 并且和液滴模型理论做了比较. 相似文献
17.
用790MeV136Xe轰击56Fe靶,测量了类靶碎片的质量数和原子序数。探测且鉴定了四个丰中子同位素54Ti,56V,57V,58Cr。同时提供了55Ti,58V,59Cr存在的可能性。使用西德重离子研究中心的磁谱仪和磁分析一起进行了飞行时间和ΔE-E测量,同位素鉴定是可靠的。 相似文献
18.
Utilizing the cross sections for 93Nb(n, 2n)93mNb or 27Al(n, a)24Na reactions as monitors, the cross sections for the reactions 115Sn(n, p)115mIn, 116Sn(n, p)116mIn, 117Sn(n, p)117In and 117Sn(n, p)117mIn have been measured at neutron energy ranging from 13.5 to 14.6 MeV through activation technology. Then, the results of present work were compared with the published experimental data. 相似文献
19.
This paper described the nuclear astrophysical studies using the unstable ion beam facility GIRAFFE in CIAE, by indirect measurements. We measured the angular distributions for some single proton or neutron transfer reactions, such as 7Be(d,n)8B, 11C(d,n)12N, 8Li(d,p)9Li and 13N(d,n)14O in inverse kinematics, and derived the astrophysical S-factors or reaction rates of 7Be(p,γ)8B, 11C(p,γ)12N, 8Li(n,γ)9Li, 13N(p,γ)14O by asymptotic normalization coefficient, spectroscopic factor, and R-matrix approach at astrophysically relevant energies. Some most recent progress of nuclear astrophyiscal work in CIAE are also summarized. 相似文献