Physical Coordinates as Dynamic Variables in Relativistic Theories

We show that relativistic theories of strings and of gravity that are invariant with respect to general covariance transformations can be formulated in terms of physical coordinates with nonzero evolution Hamiltonians by identifying these coordinates with some dynamic variables.     

Exact solution in a string cosmological model

We construct an exact solution of the Friedmann equations with a phantom scalar matter field originating in string field theory and show the absence of the big-rip singularity. The notable features of the model are a ghost sign of the kinetic term and a special polynomial form of the effective tachyon potential. The constructed solution is stable under small fluctuations of the initial conditions and special variations of the form of the potential. __________ Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 148, No. 1, pp. 23–41, July, 2006. An erratum to this article is available at .     

Recent observations of anomalous cosmic rays made with solid track detectors

A few exposures of CN-85 detectors on Earth-orbiting satellites in the period 1993–1994 show evidence for the reappearance of the radiation belt from geomagnetically trapped anomalous cosmic ray ions.     

焦利斯秤在实验中的应用

对利期称稍加改装后可作七个题目的实验，充分发挥该仪器的效能，并且能提高实验精度．文章中介绍了单摆测重力加速度的实验，测声速的实验和弦振动的实验的作法．     

Double Structures and Multiple Symmetry Groups for the Reduced 4-Dimensional String Background Equations

By using the extended double complex method proposed previously, the 1-loop string background equations with axion and dilaton fields in 4 dimensions with two commuting Killing symmetries and c = 0 are reduced essentially to two double Ernst -models. Then the string Geroch group acting on the solution space is extended to a multi-fold version of a semidirect product of the string Geroch group and the Virasoro group. The usual string Geroch group is just one component of a subgroup in the multi-fold semidirect product group. It is also found that a dobule Z₂ symmetry exists for every case of the 4-dimensional reduced string equations and for most of the cases here, this Z₂ symmetry is new and cannot be obtained in the usual (non-double) scheme. These results show that the reduced string background equations considered possess more and richer symmetry structures than previously expected. Moreover, a double form of string soliton method is briefly described and, as an application, a multiple family of soliton solutions of the considered reduced string equations is given, which shows that the double method is more effective.     

Null Limits of the C-Metric

The C-metric is usually understood as describing two black holes which accelerate in opposite directions under the action of some conical singularity. Here, we examine all the solutions of this type which represent accelerating sources and investigate the null limit in which the accelerations become unbounded. We show that the resulting space-times represent spherical impulsive gravitational waves generated by snapping or expanding cosmic strings.     

Significance of the second dip in the ultra-high energy cosmic ray spectrum

A new feature in the spectrum of ultra high energy cosmic rays (UHECR) has been announced in the paper by Berezinsky, Gazizov and Kachelrieβ. The ratio of the solution of the exact transport equation to its solution in the continuous energy loss limit shows intriguing features which, according to the Authors, are related to the very nature of the energy loss processes of UHECR: the very sharp second dip predicted at 6.3 × 10¹⁹ eV can be used as an energy calibration point and also as the UHECR mass indicator for big future cosmic ray experiments. In the present paper we would like to advocate that this statement is an overinterpretation. The second dip is a result of an inappropriate approximation used, and thus it cannot help to understand the nature of UHECR in any way.      

Plane Symmetric String Cosmological Model in Modified Theory of General Relativity

It is shown that homogeneous plane symmetric string cosmological model for Takabayasi string i.e. ρ=(1+ω)λ does not exist in Barber’s second self creation theory. Further it is found that the string cosmological model in this theory exist only when ω=0. Therefore model for ρ=λ (geometric string) is constructed. Some physical and geometrical properties of the model are discussed.     

New evidence for lack of CMB power on large scales

A digitalized temperature map is recovered from the first light sky survey image published by the Planck team, from which an angular power spectrum of the cosmic microwave background (CMB) is derived. The amplitudes of the low multipoles (low-l) measured from the preliminary Planck power spectrum are significantly lower than those reported by the WMAP team. Possible systematical effects are far from enough to explain the observed low-l differences.     

Characteristics of the sampling paddle modules of neutron wall from the cosmic ray test

In the construction of a large area neutron detector （neutron wall） that is used to detect neutrons at GeV energies, the performances of all the sampling paddle modules prepared for the neutron wall are investigated with a specially designed test bench. Tested by cosmic rays, an average intrinsic time resolution of 222.5 ps is achieved at the center of the modules. The light attenuation length and the effective speed of the light in the module are also investigated.