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排序方式: 共有190条查询结果,搜索用时 15 毫秒
1.
Hyperfine Interactions - Rotational J=1→J=0 transitions in muonic molecule, (3Heμd) J ++, in [(3Heμd)++,2e]–D and [(3Heμd)++,e]+–D collisions are considered. The... 相似文献
2.
The linearized stability of charged thin shell wormholes under spherically symmetric perturbations is analyzed. It is shown that the presence of a large value of charge provides stabilization to the system, in the sense that the constraints onto the equation of state are less severe than for non-charged wormholes. 相似文献
3.
Jai Kumar Singhal 《Pramana》2004,62(5):1029-1040
We examine the effects of mixing induced light heavy charged lepton neutral currents on the partial wave amplitude for the
process l+l− →ZZ (withl = e,μ or τ). By imposing the constraints that the amplitude should not exceed the perturbative unitarity limit at high energy (√s
= Λ), we obtain bounds on light heavy charged lepton mixing parameter sin2(2θ
L
a
) where θ
L
a
is the mixing angle of the ordinary charged lepton with its exotic partner. For Λ = 1 TeV, no bound is obtained on sin2 (2θ
L
a
) form
E < 0.69 TeV. However, sin2 (2θ
L
a
) ≤ 1.52×10−5 form
E = 5 TeV, sin2 (2θ
L
a
) ≤ 2.41 ×10−7 form
E = 10 TeV. Similarity for Λ = ∞ no bound is obtained on sin2 (2θ
L
a
) for mE < 1.97 TeV and sin2 (2θ
L
a
) ≤ 0.15 form
E = 5 TeV and sin2 (2θ
L
a
) ≤ 3.88×10-2 form
E = 10 TeV. 相似文献
4.
S. Bhattacharyya A. N. Sil T. K. Mukherjee P. K. Mukherjee P. Vasu 《International journal of quantum chemistry》2007,107(4):946-951
Electron affinity of plasma embedded muonium (μ+e?) and pionium (π+e?) has been estimated using a general three‐body formalism within variational framework. Electron correlation is taken care of using extended Hylleraas basis sets. The stability of the three‐body systems have been studied under the Debye screening model of the plasma, which changes the Coulombic potential to the screened Coulomb one. The electron affinity of the muonium and pionium is maximum for free systems, and it decreases gradually toward zero with increase of the plasma strength, which tends to push the three‐body system toward gradual instability. The electron correlation contribution to the affinity has been analyzed. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007 相似文献
5.
The L3+C experiment, taking advantage of the L3 muon magnetic spectrometer, measured the spatial tracks of charged cosmic ray particles to obtain rigidity as well as velocity. One possible low velocity exotic particle is observed. The existing uncertainties are discussed, and the flux upper limit of the low velocity exotic particles from this observation is deduced based on the assumption of a null observation. The result is 6.2×10^-10 cm^-2·s^-1·sr^-1 at 90% confidence level in the velocity range from 0.04c to 0.5c. 相似文献
6.
Lü LinHui YE YanLin JIANG DongXing HUA Hui ZHENG Tao LI ZhiHuan GE YuCheng LI XiangQing LOU JianLing CAO ZhongXin SONG YuShou XIAO Jun LI QiTe QIAO Rui YOU HaiBo CHEN RuiJiu XU HuShan WANG JianSong GUO ZhongYan ZHANG XueYing LI Chen HU ZhengGuo CHEN RuoFu WANG Meng XU ZhiGuo YUE Ke TANG Bin ZANG YongDong ZHANG XueHeng YAO XiangWu CHEN JinDa & BAI Zhen School of Physics State Key Laboratory of Nuclear Physics Technology Peking Universit... 《中国科学:物理学 力学 天文学(英文版)》2011,(Z1)
Knockout reaction experiment was carried out by using the 6He beams at 61.2 MeV/u impinging on a CH2 target. The α core fragments at forward angles were detected in coincidence with the recoiled protons at larger angles. From this exclusive meas urement the valence nucleon knockout mechanism and the core knockout mechanism can be distinguished by the relation be tween the polar angles of the core fragments and the recoiled protons, respectively. It is demonstrated that the core knockout mechanism may result... 相似文献
7.
We investigate the quantum numbers of the pentaquark states ${{\rm{P}}}_{{\rm{c}}}^{+}$, which are composed of 4 (three flavors) quarks and an antiquark, by analyzing their inherent nodal structure in this paper. Assuming that the four quarks form a tetrahedron or a square, and the antiquark is at the ground state, we determine the nodeless structure of the states with orbital angular moment L≤3, and in turn, the accessible low-lying states. Since the inherent nodal structure depends only on the inherent geometric symmetry, we propose the quantum numbers JP of the low-lying pentaquark states ${{\rm{P}}}_{c}^{+}$ may be ${\tfrac{3}{2}}^{-}$, ${\tfrac{5}{2}}^{-}$, ${\tfrac{3}{2}}^{+}$and ${\tfrac{5}{2}}^{+}$, independent of dynamical models. 相似文献
8.
陈云华 《中国物理C(英文版)》2020,(2):42-50
We study the contributions of intermediate bottomonium-like Zb states and the bottom meson loops in the heavy quark spin flip transitionsγ(4 S)→hb(1 P,2 P)π+π-.Depending on the constructive or destructive interferences between the Zb-exchange and the bottom meson loops mechanisms,we predict two possible branching ratios for each process:BRγ(4 S)→hb(1 P)π+π-≈(1.20.40.8×10^-6)or(0.5-0.20.5×10^-6),and BRγ(4 S)→(2 P)π+π-≈(7.1-1.1+1.7×10^-10)or(2.4-0.10.2×10^-10)).The contribution of the bottom meson loops is found to be considerably larger than that of the Zbexchange in the T(4 S)→hb(1 P)ππtransitions,while its decay rates are not comparable to those of heavy quark spin conservedγ(4 S)→γ(1 S,2 S)ππprocesses.We also predict the contribution of the charm meson loops in the branch fractions ofΨ(3 S,4 S)→hc(1 P)ππ. 相似文献
9.
The three lowest-lying states, i.e., (1S), (2S), and (3S), composed of bb¯ pairs and below the BB ¯ threshold, provide a good platform for the researches of hadronic physics and physics beyond the Standard Model. They can be produced directly in e+e− colliding experiments, such as CLEO, Babar, and Belle, with low continuum backgrounds. In these experiments, many measurements of the exclusive (1S) and (2S) decays into light hadrons, which shed light on the “80% rule” for the Okubo–Zweig–Iizuka suppressed decays in the bottomonium sector, were carried out. Meanwhile, many studies of the charmonium and bottomonium productions in (1S, 2S, 3S) decays were performed, to distinguish different Quantum Chromodynamics (QCD) models. Besides, exotic states and new physics were also extensively explored in (1S, 2S, 3S) decays at CLEO, BaBar, and Belle. The (1S, 2S, 3S) states can also be produced in pp collisions and in collisions involving heavy ions. The precision measurements of their cross sections and polarizations at the large hadron collider (LHC), especially in the CMS, ATLAS, and LHCb experiments, help to understandΥproduction mechanisms in pp collisions. The observation of the sequentialΥsuppression in heavy ion collisions at CMS, LHCb, and ALICE is of great importance for verifying the quark–gluon plasma predicted by QCD. In this article, we review the experimental results on (1S, 2S, 3S) at e+e− colliders and the LHC, and summarize their prospects at Belle II and the LHC. 相似文献
10.
Malcolm Fairbairn 《Contemporary Physics》2017,58(1):1-24
In 2010, the MoEDAL (MOnopole and Exotics Detector at the LHC) experiment at the Large Hadron Collider (LHC) was unanimously approved by European Centre for Nuclear Research’s Research Board to start data taking in 2015. MoEDAL is a pioneering experiment designed to search for highly ionising manifestations of new physics such as magnetic monopoles or massive (pseudo-)stable charged particles. Its groundbreaking physics programme defines a number of scenarios that yield potentially revolutionary insights into such foundational questions as: are there extra dimensions or new symmetries; does magnetic charge exist; what is the nature of dark matter; and, how did the Big Bang develop. MoEDAL’s purpose is to meet such far-reaching challenges at the frontier of the field. The innovative MoEDAL detector employs unconventional methodologies tuned to the prospect of discovery physics. The largely passive MoEDAL detector, deployed at Point 8 on the LHC ring, has a dual nature. First, it acts like a giant camera, comprised of nuclear track detectors – analysed offline by ultra fast scanning microscopes – sensitive only to new physics. Second, it is uniquely able to trap the particle messengers of physics beyond the Standard Model for further study. MoEDAL’s radiation environment is monitored by a state-of-the-art real-time TimePix pixel detector array. A new MoEDAL sub-detector designed to extend MoEDAL reach to mini-charged, minimally ionising particles is under study. 相似文献