Nonequilibrium fluctuations in μ space

The properties of fluctuations in space in or outside thermal equilibrium are obtained by solving hierarchies of equations derived either from the Liouville or the Master equation. In particular we study the one-, two-, etc., time correlation functions that describe the spatial and temporal behavior of the fluctuations in space. Explicit solutions are obtained for a dilute gas. The Langevin approach is briefly discussed. Our results are compared with those obtained in the extensive literature, which is reviewed in some detail.     

The “Golden” cLFV channels μ → eγ and μ → eee — the high-intensity frontier

The muon as a laboratory for studying charged lepton-flavour violation (cLFV) has proven to be one of the most sensitive areas to probe for “New Physics”, due to the muon’s copious production rate and relatively long lifetime. The search at the intensity frontier with precision-type experiments is complementary to the search for new particles at the high-energy frontier of TeV colliders. Of the three “golden” muon channels: μ → eγ, μ → 3e and μ → e conversion, an overview of the status of the coincidence experiments MEG, together with the latest results, which constitute the most stringent limit to date on this decay and the recently initiated Mu3e experiment, will be given.     

A simple geometric representative for μ of a point

ForSU(2) (orSO(3)) Donaldson theory on a 4-manifoldX, we construct a simple geometric representative for of a point. Letp be a generic point inX. Then the set {[A]F _A ^– (p) is reducible}, with coefficient –1/4 and appropriate orientation, is our desired geometric representative. The construction is an exercise in real algebraic geometry in the style of Ehresmann and Pontryagin.This work is partially supported by an NSF Mathematical Sciences Postdoctoral Fellowship and Texas Advanced Research Project grant ARP-037.     

Application of μ SR to radiation damage in metals

Proton-irradiated Al, Cu and Ni foils have been investigated by the SR technique. No trapping of ⁺ has been observed in the temperature range investigated (<300 K). In Ni a temperature-independent increase of the depolarisation rate by a factor of three is found for the irradiated target. This change is attributed to field inhomogeneities produced by defects.     

Cutoff effects in lattice actions at μ ≠ 0

We look at the cutoff dependence of several lattice actions, including two improved actions viz. Naik and p4, and and chirally-invariant ones, namely fixed-point, overlap and domain-wall, with the aim of understanding its behavior at μ ≠ 0. Apart from numerical results, we also derive a series expansion in N _r ⁻¹ for the free-gas pressure. We find that actions with O(a ⁿ )-improved rotational invariance produce O(a ⁿ )-improvement in the pressure. The series for unimproved overlap and domain-wall fermions are identical to the naive series, and hence using Naik or p 4 kernels should produce improvement in these formulations as well. Lastly, we find that actions that are improved at μ = 0 remain so as the chemical potential is turned on. The series coefficients become μ-dependent now, however their functional form at any given order is the same for all actions.     

X-ray intensities following the fusions of dμd,dμt and pμd

Muonic X-ray spectra of μ³He and μ⁴He from dμd, pμd, and dμt fusion are analyzed for various target densities. Theoretical values of the intensity ratio μ³He(3→1)/μ³He(2→1) for dμd and pμd fusion at liquid hydrogen density are, respectively, 0.132 and 0.0553. These are in good agreement with the experimental results.     

New polymorphs of alumina: Part II μ and λ alumina

Abstract

We had reported observation of polymorphs of alumina having rare earth sesquioxide type structures in xerogel γ alumina (XGA) at high pressures and temperatures (High Pressure Research, 1998). In this paper we report observation of two additional phases at somewhat different pressures and temperatures. The XGA quenched from 5.2 GPa and 1450°C showed, besides α Al₂O₃, a new hexagonal metastable polymorph μAl₂O₃. Over a period of 10 to 12 weeks μ A1₂O₃ transforms to a stable hexagonal phase λ Al₂O₃. The cell parameters of λ Al₂O₃ are comparable with those of k Al₂O₃ found by Saalfield on dehydration of gibbsite A1₂O₃3H₂O in air at 800°C. The XGA containing 1 wt% of Cr₂O₃ yielded similar results at 4.56GPa and 1100°C. Further the XGA containing Cr showed complete transformation to n Al₂O₃ at 5.2 GPa and 1520°C.     

Measurement of the μ decay spectrum with the ICARUS liquid Argon TPC

Examples are given which prove the ICARUS detector quality through relevant physics measurements. We study the decay energy spectrum from a sample of stopping events acquired during the test run of the ICARUS T600 detector. This detector allows the spatial reconstruction of the events with fine granularity, hence, the precise measurement of the range and dE/dx of the with high sampling rate. This information is used to compute the calibration factors needed for the full calorimetric reconstruction of the events. The Michel parameter is then measured by comparison of the experimental and Monte Carlo simulated decay spectra, obtaining . The energy resolution for electrons below MeV is finally extracted from the simulated sample, obtaining .Received: 20 November 2003, Published online: 4 February 2004     

Level shift of μ mesoatoms and anomalous interaction of muons with nuclei

The effect of the possible anomalous interaction of a muon with nuclei, due to exchange of the muon and the nucleon, with vector V=⁰, , , J/, , and ⁰ mesons, on the level of the mesoatoms is considered. An estimate is carried out of the energy shift of the 2P-1S transition. A comparison of the estimates obtained for the 2P-1S transition energy shift in the mesoatom²⁰⁶Pb with the experimental data does not contradict the presence in the muon of an anomalous interaction with the nucleon, defined by the effective coupling constant /4 4·10^–4.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 75–80, June, 1978.     

Robust μ -stability for uncertain stochastic neural networks with unbounded time-varying delays

In this paper, we investigate the global robust stability for uncertain stochastic neural networks with unbounded time-varying delays and norm-bounded parameter uncertainties. A new concept of global robust μ-stability in the mean square for neural networks is given first, then by means of the linear matrix inequality (LMI) approach, stability criteria are presented. Several corollaries are also derived. A simple example is presented to demonstrate the effectiveness of the main result.     

Be~9(d,p),(d,t),(d,a)反应研究

本文在E_d=0.1—2.5MeV能量范围内,研究了Be~9(d,p_0)Be~(10)(0),Be~9(d,p_1)Be~(10)(3.368MeV),Be~9(d,t_0)Be~8(0),Be~9(d,α_0)Li~7(0)及Be~9(d,α_1)Li~7(0.478MeV)诸反应。在E_d=0.150,0.220,0.401,0.706,1.005,1.301,1.484,1.750,2.000,2.250和2.500MeV共十一个能量上分别测量了这五群出射粒子在θ_L=10—155°区间的角分布。在θ_L=135°,E_d=0.1—2.5MeV,在θ_L=95°,E_d=0.1—2.2MeV,和在θ_L=112.5°,E_d=0.5—2.5MeV测量了Be~9(d,p_0)Be~(10)的激发函数。在θ_L=135°和112.5°,E_d=1.2MeV,用较厚靶(100—300μg/cm~2)测量了Be~9(d,p_0)Be~(10)(0)反应的截面绝对值,结果为σ_p_0(θ_L=135°)=1.60mb/sr,σ_p_0(θ_L=112.5°)=1.55mb/sr。这样就得到了在此能区内,这五群出射粒子的截面情况。对所得结果进行了一些讨论。     

Microscopic description of the reactions d + d → p + 3H and d + d → n + 3He at low energies

A collective adiabatic approach is used to explore the total and differential cross sections for the reactions d + d → p + ³H and d + d → n + ³He at incident-deuteron energies of up to 6 MeV. All substantially contributing partial waves of order not higher than that of G waves are taken into account. The experimental value of the difference of the cross sections for the above mirror reactions is reproduced theoretically under the assumption that nuclear forces obey the condition of isotopic invariance. The positions and amplitudes of the maxima in the calculated total cross sections virtually coincide with those of the corresponding experimental values. It is shown that, around the maxima of the cross sections under study, dominant contributions to them come from the P wave. The sensitivity of observables to the parameters of nucleon-nucleon interaction is analyzed.     

The nuclear structure of 126Te studied with (d,p), (d,3He) and (d,d′) reactions

At the Munich Tandem Accelerator the reactions ¹²⁵Te(d, p)¹²⁶Te, ¹²⁶Te(d, d′)¹²⁶Te and ¹²⁷I(d, ³He)¹²⁶Te were measured with deuteron energies between 24 and 28 MeV up to excitation energies of about 3.2 MeV. Using γ-lines from previous (n,γ), (n,n′γ) and (γ,γ′) experiments, a level scheme of ¹²⁶Te up to above 3 MeV was established. The results are compared with quasiparticle-phonon model calculations.     

新型4d/5d基超导体的结构和物性

在强关联电子体系中,轨道、自旋和晶格等自由度之间的相互作用一直是研究的热点.这些自由度之间的竞争和共存产生了复杂新奇的物理现象,如超导现象、量子相变、自旋有序、拓扑相变、金属绝缘转变等,这些丰富的物理现象来源于不同的有序态或量子涨落之间的竞争和耦合.自旋轨道耦合作用是指粒子的自旋角动量和轨道角动量之间的相互作用,在4d/5d基化合物中,由于电子的运动速度较快,自旋轨道耦合的效应不可忽视,可能表现出与3d基化合物不同的物性.例如,在含4d/5d过渡族金属元素的超导体中,其电子配对的机制可能不同于常规的s波Bardeen-Cooper-Schrieffer超导体.本文以几种典型的4d/5d基超导体为例,对其晶体结构和超导物性及其内在联系进行了详细论述,重点探讨了阴离子共价键强弱对晶体结构、相变和超导物性的影响,希望引起相关研究者对该类超导体的重视.     

Density effect in d - d catalyzed fusion with ortho-and para-enriched deuterium

The ortho-para dependence of d-d fusion neutrons time spectra has been investigated using different target densities at similar temperatures. Even at the similar temperatures, the ortho-para effect on the fusion neutron yields in the liquid phase showed the opposite tendency from that in the gas phase. The result evidenced significant density dependence on resonant ddμ formation.     

Be9(d,p),(d,t),(d,a)反应研究

本文在E_d=0.1—2.5MeV能量范围内,研究了Be⁹(d,p₀)Be¹⁰(0),Be⁹(d,p₁)Be¹⁰(3.368MeV),Be⁹(d,t₀)Be⁸(0),Be⁹(d,α₀)Li⁷(0)及Be⁹(d,α₁)Li⁷(0.478MeV)诸反应。在E_d=0.150,0.220,0.401,0.706,1.005,1.301,1.484,1.750,2.000,2.250和2.500MeV共十一个能量上分别测量了这五群出射粒子在θ_L=10—155°区间的角分布。在θ_L=135°,E_d=0.1—2.5MeV,在θ_L=95°,E_d=0.1—2.2MeV,和在θ_L=112.5°,E_d=0.5—2.5MeV测量了Be⁹(d,p₀)Be¹⁰的激发函数。在θ_L=135°和112.5°,E_d=1.2MeV,用较厚靶(100—300μg/cm²)测量了Be⁹(d,p₀)Be¹⁰(0)反应的截面绝对值,结果为σ_(p0)(θ_L=135°)=1.60mb/sr,σ_(p0)(θ_L=112.5°)=1.55mb/sr。这样就得到了在此能区内,这五群出射粒子的截面情况。对所得结果进行了一些讨论。     

A trial wave function to study of the structure of the molecular dd μ ion

This paper provides a new effort to study of the ddμ structure. The present work is numerically performed using a new trial wave function to the ddμ system in configuration of coupled channels. The present results of energies are more accurate than those of our previous work. The obtained results of formation rates are close to results published by Yu.V. Petrov et al. and giving strong indications that the trial wave function is good enough in determining the resonance states of the mentioned ionic molecule.     

40≤Z≤44类镍离子3d94s,3d94p,3d94d组态s-p,p-d跃迁的计算

用多组态自洽场方法,结合我们提出的半经验拟合公式,对40≤Z≤44类镍离子3d94s,3d94p,3d94d态的能级进行计算,根据能级拟合值算出s-p,p-d跃迁的谱线波长,并给出各谱线的HFR振子强度.     

Angular correlations in the inelastic-scattering process 24Mg(d, dγ)24Mg at E d = 15.3 MeV

The double-differential cross sections for the reaction ²⁴Mg(d, dγ _1.369)²⁴Mg at the projectiledeuteron energy of E _d = 15.3 MeV weremeasured for deuteron emission angles in the forward hemisphere. All even spin-tensor components of the density matrix for the 2⁺ state of the ²⁴Mg nucleus at 1.369 MeV were reconstructed, and its orientation properties were determined. These experimental results were compared with the results of calculations based on various versions of the coupled-channel method.