Recent experiments on muon transfer in gas mixtures

The experimental muon transfer rates from muonic protium and deuterium to heavier elements show a complexZ dependence. Instead of the expected monotonicZ dependence considerable variations between neighboring elements are observed. Transfer to neon has a specially small rate. Furthermore, the time distribution of the muonic X-rays shows in a number of molecules a complex structure, and depends in the case of a H₂ + CH₄ gas mixture also on the total pressure.     

Physical applications of muon catalysis: Muon capture in hydrogen

Results of theoretical and experimental research on capture of negative muons in hydrogen are reported with an emphasis on the accompanying phenomenon of muon catalysis in hydrogen and subtleties of the experimental method. A conclusion is drawn that precise determination of the capture rate is important for refining the standard model.     

Isotopic catalysis and isotopic analysis

Isotopes with magnetic nuclei accelerate the biochemical reactions of adenosine triphosphate synthesis by a factor of two to three. An isotope effect in which isotopes are preserved in the reaction system is known as isotopic catalysis. It has been revealed in enzymatic reactions catalyzed by magnesium, zinc, and calcium ions. Isotopic catalysis is sensitive to paramagnetic impurities, which inhibit it. It is shown that the presence of paramagnetic iron ions eliminates isotope effect and suppresses the isotopic catalysis of adenosine triphosphate synthesis.     

Experimental observation of excited state muon transfer in mixtures of hydrogen isotopes

Molecular dynamic (MD) computer simulations are used to investigate the stopping of heavy ions in strongly coupled electron plasmas. Our results show, that in this regime collisions between the electrons as well as non-linear screening effects yield at low ion velocities a dependence of the stopping power on the ion chargeZ which scales like Z^1.43 instead of the usual Z² ln(const/Z)-scaling for weak coupling. This is connected with an enhanced local density of electrons around a highly charged, slow ion.Supported by the Bundesministerium für Bildung und Forschung (BMBF), the Gesellschaft für Schwerionenforschung Darmstadt (GSI) and the European Community.     

Present status of the investigation on muon transfer in gaseous mixtures of hydrogen and oxygen

To investigate the energy dependence of muon transfer to oxygen, we performed measurements in gaseous mixtures of hydrogen and oxygen. The time distributions of the muonic oxygen X-rays showed the same structure as the one observed earlier in H₂+SO₂ mixtures. In the delayed part of these distributions, one can distinguish a short-time and a long-time component. From the latter, we deduced the transfer rates from thermalized muonic protium, respectively deuterium, to oxygen. The short-time component can be interpreted as being due to muon transfer from epithermal muonic hydrogen atoms. The time parameters are characteristic for the deceleration process as well as for energy-dependent transfer rates. With results of recent research on the formation and the thermalization of muonic hydrogen, we performed Monte Carlo simulations in order to test the hypothesis of an energy-dependent transfer rate.     

Calculation of deexcitation and muon transfer rates in collisions of excited muonic atoms in hydrogen mixtures

The competition of the processes responsible for muonic hydrogen deexcitation and charge exchange is considered for various isotopic mixtures. The energy dependence as well as then-dependence of the process rates are analyzed in the framework of the WKB method. Electron screening is taken into account.     

Extracting muon momentum scale corrections for hadron collider experiments

The quark condensate is calculated within the world-line effective-action formalism, by using for the Wilson loop an ansatz provided by the stochastic vacuum model. Starting with the relation between the quark and the gluon condensates in the heavy-quark limit, we diminish the current quark mass down to the value of the inverse vacuum correlation length, finding in this way a 64?% decrease in the absolute value of the quark condensate. In particular, we find that the conventional formula for the heavy-quark condensate cannot be applied to the c-quark, and that the corrections to this formula can reach 23?% even in the case of the b-quark. We also demonstrate that, for an exponential parametrization of the two-point correlation function of gluonic field strengths, the quark condensate does not depend on the non-confining non-perturbative interactions of the stochastic background Yang?CMills fields.     

Quantitative analysis of solid-phase mixtures by Raman spectroscopy

We propose a method for using Raman spectroscopy to determine the phase compositions and concentrations in solid-phase equilibrium mixtures. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 3, pp. 416–418, May–June, 2008.     

Sum rules including first order quantum corrections for neutron scattering experiments on isotopic mixtures of monatomic fluids

The sum rules for neutron scattering experiments on monatomic isotopic mixtures are studied. The scattering is separated into a self part and a distinct part rather than into an incoherent part and a coherent part. Exact expressions for the moments are derived in terms of polynomials in ? ². The coefficients in these polynomials are sums of averages of hermitean operators that have a classical analogue. For the interpretation, the coefficients are approximated including first order quantum corrections.

It is argued that the separation into coherent and incoherent scattering is not justified in the presence of ‘isotopic incoherence’. Approximate expressions for the sum rules are proposed, in which combined averages (over the isotopic composition) appear of the scattering amplitudes and masses of the scattering atoms. These expressions, including first order quantum corrections to the sum rules, are not available in the literature.

The importance of correct averaging over the isotopic composition of expressions that involve scattering amplitudes and masses is discussed for the case of a maximum incoherent mixture of ³⁶Ar and ⁴⁰Ar.     

Rapid and quantitative detection of ethanol proportion in ethanol-gasoline mixtures by Raman spectroscopy

The paper reports a Raman spectral in-situ detection technique to measure the ethanol proportion in an ethanol-gasoline mixture rapidly and quantitatively. The transformed information of Raman spectra for different mixtures of gasoline and ethanol have been observed and recorded. The relative intensity ratio of two typical Raman peaks for ethanol and gasoline satisfies a linear relation with a variation in volume ratio which could be used as a quantitative measure. This method, compared with the direct intensity measurement of a Raman peak, may not only eliminate the random measurement error due to dark current, but also confirm the accurate the proportion of ethanol and gasoline.     

Facility for preparation of gas mixture in muon catalyzed fusion experiments

A facility is described that allows safe handling of high tritium gas activity as dozens kilocuries in a regular laboratory environment. It is used to make and deliver into the target a mixture of specific isotopic composition with the contamination requirement of 10^-7 v.f. for Z>1 elements, and recover it upon completion of operation. With this facility, efforts have been accomplished to investigate into the muon catalyzed fusion on two targets – liquid tritium and high-pressure tritium types. Also, the operation range was 0.1–120 MPa for pressure and 20–800 K for temperature and the amount of tritium used was about 100 kCi. The facility showed reliability in operation without indications of radiation beyond the safety level. This revised version was published online in August 2006 with corrections to the Cover Date.     

缪子物理实验现状及发展前景

寻找超出标准模型的新物理是当前粒子物理学最重要的任务之一。 缪子物理实验,包括带电轻子味道破坏,缪子反常磁矩和电偶极矩,缪子素到反缪子素转换等是高强度前沿新物理研究的热点领域。文章介绍了国际上在这一领域开展实验的现状和展望,特别的,介绍了未来在中国开展相关实验的前景。     

Transition processes in the novel method of the muon catalysis investigation

The problem of modifying the interpretation of the results to be obtained with the novel method of muon catalysis investigation to take the fast transition processes into account is first considered. The results of exploring the process kinetics are compared with the ones found from the analysis of the appropriate Monte Carlo distributions. The calculation programs simulate both the kinetics and the registration system of the experiment which is now performed in the frame of the large international project TRITON. The main conclusion is that the multiplicity distribution of the fusion neutrons is “invariant” under any assumptions of the fast transition stage. This revised version was published online in July 2006 with corrections to the Cover Date.     

Tritium gas handling system for muon catalyzed fusion research at RIKEN-RAL muon facility

For muon catalyzed fusion (μCF) experiments at RIKEN-RAL muon facility, a tritium gas handling system for a high purity D–T target, free from ³ component, has been constructed to perform precise measurements of α-sticking probability in the μCF cycle. The system has been constructed to enable us to purify the target D–T gas by removing ³He component, to adjust the D/T mixing ratio, and to measure the hydrogen isotope components at the experiment site. The whole performance has been confirmed and a tritium gas with the inventory of 56 TBq (1500 Ci) has been operated in the system. This revised version was published online in August 2006 with corrections to the Cover Date.     

激光拉曼光谱分析氢同位素的应用

拉曼光谱作为一种物质结构和成分分析的测试手段而被广泛应用.介绍分析了激光拉曼光谱法用于氢同位素分析的可行性,并综述介绍了国内外研究人员利用激光拉曼光谱在氚参与的放射反应监测分析、氢同位素定性检测、定量分析方法研究等方面开展的工作.     

Emission of muonic tritium into vacuum: An atomic beam for muon experiments

The emission of muonic tritium atoms from a thin film of hydrogen isotopes into vacuum was observed. The time and position of the muon decays were measured by tracking the decay electron trajectory. The observations are useful both for testing the theoretical cross sections for muonic atomic interactions, and producing an atomic beam of slow μ^-t with a controllable energy. This revised version was published online in August 2006 with corrections to the Cover Date.     

Raman spectral analysis of the intermolecular hydrogen bond in bromoform

The maximum of the perpendicular polarized component of the Raman spectrum of the C−H mode in liquid bromoform shifts by 1.5 cm⁻¹ toward higher frequencies from the maximum of the parallel polarized component. A high-frequency shift of this band is noted in solution with nitromethane and nitrobenzene, and the shape of the band becomes more complex. The result is attributed to superposition of the associate lines in the mixture (the high-frequency component) and the monomer line. There are indications that the 537 cm⁻¹ band of bromoform in a mixture with the same solvents and with pyridine has a doublet character. When CHBr₃ is dissolved in a neutral solvent such as heptane, both bands exhibit normal behavior, the widths of the lines decreasing presumably because of an increase in the vibrational relaxation time. A. Navoi State University, Samarkand. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 90–94, December, 1998.