Search for lepton flavor violation in supersymmetric models via meson decays

Considering the constraints from the experimental data on μ→eγ$\mu \to e\gamma$, μ→3e$\mu \to 3e$, μ–e$\mu \text{–}e$ conversion, etc., we analyze the lepton flavor violating decays ?(J/Ψ,?(1S))→e⁺μ⁻(μ⁺τ⁻)$?(J/\Psi ,?(1S))\to e^{+}{\mu }^{-}({\mu }^{+}{\tau }^{-})$ in the scenarios of the minimal supersymmetric extensions of Standard Model with seesaw mechanism. Numerically, there is parameter space that the LFV processes of J/Ψ(?)→μ⁺τ⁻$J/\Psi (?)\to {\mu }^{+}{\tau }^{-}$ can reach the upper experimental bounds, meanwhile the theoretical predictions on μ→eγ$\mu \to e\gamma$, μ→3e$\mu \to 3e$, μ–e$\mu \text{–}e$ conversion satisfy the present experimental bounds. For searching of new physics, lepton flavor violating processes J/Ψ(?)→μ⁺τ⁻$J/\Psi (?)\to {\mu }^{+}{\tau }^{-}$ may be more promising and effective channels.     

Supersymmetric lepton flavor violation in a linear collider: the role of charginos

The occurrence of significant supersymmetric lepton flavor violation at laboratory energies, through – mixing, has become a realistic possibility in the wake of the super-Kamiokande atmospheric neutrino result. This effect can be observed in an linear collider with the distinct final state . We show that the pair production of charginos can make an important contribution to this process and has to be taken into account in addition to that of sneutrinos or charged sleptons. Some case studies are presented with CM energies of 500 and 800GeV and integrated luminosities of 50, 500 and 1000. Received: 14 March 2001 / Published online: 19 July 2001     

Search for lepton flavor violation in the decay tau+/--->e+/-gamma

A search for the nonconservation of lepton flavor in the decay tau+/--->e+/-gamma has been performed with 2.07x10(8) e+e--->tau+tau- events collected by the BABAR detector at the SLAC PEP II storage ring at a center-of-mass energy near 10.58 GeV. We find no evidence for a signal and set an upper limit on the branching ratio of Beta(tau+/--->e+/-gamma)<1.1x10(-7) at 90% confidence level.     

Search for lepton flavor violation in the decay tau+/- --> mu+ gamma

A search for the nonconservation of lepton flavor number in the decay tau(+/-) --> mu(+/-) has been performed using 2.07 x 10(8) e(+ )e(-) tau(+) tau(-) events produced at a center-of-mass energy near 10.58 GeV with the BABAR detector at the PEP-II storage ring. We find no evidence for a signal and set an upper limit on the branching ratio of Beta(tau(+/-) --> mu(+/-) gamma) < 6.8 x 10(-8) at 90% confidence level.     

The see-saw mechanism: Neutrino mixing,leptogenesis and lepton flavour violation

The see-saw mechanism to generate small neutrino masses is reviewed. After summarizing our current knowledge about the low energy neutrino mass matrix, we consider reconstructing the see-saw mechanism. Indirect tests of see-saw are leptogenesis and lepton flavour violation in supersymmetric scenarios, which together with neutrino mass and mixing define the framework of see-saw phenomenology. Several examples are given, both phenomenological and GUT-related.      

Probing CPT violation in neutrino oscillation: A three flavor analysis

We have studied CPT violation in neutrino oscillation considering three flavor framework with matter effect. We have constructed a new way to find the oscillation probability incorporating CPT violating terms without any approximation. Then CPT   violation with atmospheric neutrinos for a magnetized iron calorimeter detector considering the muons (directly measurable with high resolution) of the charge current events has been studied for zero and nonzero θ₁₃${\theta }_{13}$ values. It is found that a potential bound of δb₃₂?6×¹⁰⁻²⁴ GeV$\delta b_{32}?6\times {10}^{-24}\text{GeV}$ at 99% CL can be obtained with 1 Mton.year exposure of this detector; and unlike neutrino beam experiments, there is no possibility to generate ‘fake’ CPT violation due to matter effect with atmospheric neutrinos. The advantages of atmospheric neutrinos to discriminate CPT violation from CP violation and nonstandard interactions are also discussed.     

Contributions to the muon’s anomalous magnetic moment from a hidden sector

The measurement of the anomalous magnetic moment of the muon provides a stringent test of the standard model and of any physics that lies beyond it. There is currently a deviation of 3.1σ between the standard model prediction for the muon’s anomalous magnetic moment and its experimental value. We calculate the contribution to the anomalous magnetic moment in theories where the muon couples to a particle in a hidden sector (that is, uncharged under the standard model) and a connector (which has nontrivial standard model gauge and hidden sector quantum numbers).     

A remark on the role of indeterminism and non-locality in the violation of Bell’s inequalities

Diederik Aerts was the first in the eighties to develop a concrete example of a macroscopic “classical” entity violating Bell’s inequalities (BI). In more recent years, he also developed a macroscopic model in which the amount of non-locality and indeterminism can be continuously varied, and used it to show that by increasing non-locality one increases the degree of violation of BI, whereas by increasing indeterminism one decreases the degree of violation of BI. In this article we introduce and analyze a different macroscopic model in which the amount of non-locality and indeterminism can also be parameterized, and therefore varied, and find that, in accordance with the model of Aerts, an increase of non-locality does produce a stronger violation of BI. However, differently from his model, we also find that, depending on the initial state in which the system is prepared, an increase of indeterminism can either strengthen or weaken the degree of violation of BI.     

An optimization method for fly’s eye integrator

By analyzing how aberrations affect the performance of a fly’s eye integrator, an efficient method to optimize the performance is put forward. A fly’s eye integrator to be used to homogenize the beam of laser diode stack is designed as an example. The optimization method achieves optimized homogeneous illumination by minimizing the aberrations that degrade the homogeneity and transmission efficiency. By this means, it is possible to substitute two spherical lenses for the Fourier lens, which is usually used in a conventional fly’s eye integrator. This helps to reduce the cost without degrading its performance.     

Spin‐Polarized Symmetric Electron‐Hole Quantum Bilayers: Finite width Effect

In this paper, the effect of finite width on ground‐state properties of a spin‐polarized symmetric electron‐hole quantum bilayers (EHBL) system is investigated at zero temperature. The quantum self‐consistent mean‐field approximation of Singwi, Tosi, Land and Sjölander (qSTLS) is adopted to explore intra‐ and interlayer properties such as the pair‐correlation function, the static density susceptibility, the local‐field corrections and the ground‐state energy. Interestingly, we noticed that due to the inclusion of finite width, the critical density for the onset of Wigner crystal (WC) phase is now lowered as compared to the recent spin‐polarized EHBL system without finite width and unpolarized EHBL system with finite width. Further, spin‐polarization effect is seem to introduce a marked change in the ground‐state energy of EHBL system as compared to that of unpolarized system. Results of ground‐state energy are also compared with the recent EHBL system without finite width (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Beyond Causal Explanation: Einstein’s Principle Not Reichenbach’s

Our account provides a local, realist and fully non-causal principle explanation for EPR correlations, contextuality, no-signalling, and the Tsirelson bound. Indeed, the account herein is fully consistent with the causal structure of Minkowski spacetime. We argue that retrocausal accounts of quantum mechanics are problematic precisely because they do not fully transcend the assumption that causal or constructive explanation must always be fundamental. Unlike retrocausal accounts, our principle explanation is a complete rejection of Reichenbach’s Principle. Furthermore, we will argue that the basis for our principle account of quantum mechanics is the physical principle sought by quantum information theorists for their reconstructions of quantum mechanics. Finally, we explain why our account is both fully realist and psi-epistemic.     

Electron impact excitation of the<Emphasis Type="Italic">D</Emphasis> states of Mg,Ca and Sr atoms: Complete experiment results

We have used non-relativistic and relativistic distorted wave approximation methods to study the excitation of then ¹ D states of magnesium (n = 3), calcium (n = 4) and strontium (n = 5) from the ground n¹ S state. Calculations have been performed for the complete set of parameters (σ, ). The results are presented for electron impact energies of 20 and 40 eV. We compare our results obtained from both the non-relativistic and relativistic methods with each other. Good agreement is found on comparison and the importance of relativistic effects is also explored.     

Ferromagnetic spin fluctuations in antiferromagnetic Pr1−xCaxMnO3: An ESR study

Electron spin resonance (ESR) measurements have been performed on polycrystalline samples of Pr_1−xCa_xMnO₃ (x=0.4, 0.5) in the temperature range of 100-300 K. The temperature dependence of ESR intensity, g value and linewidth shows the existence of ferromagnetic spin correlations in the paramagnetic state. With decreasing temperature, the ferromagnetic spin correlations switch to antiferromagnetic spin correlations in the charge ordering state and vanish at the antiferromagnetic ordering temperature T_N.